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                                  SECTION 3

                                 CONCLUSIONS


     The first three conclusions below are directly related to the specific
objectives listed in Section 1.  The ten platforms in the survey were selected
to represent a wide range with respect to production methods, production
equipment, and brine treatabilities.

     1.  The present program was successful in developing an oil content data
         base.  The results form an internally-consistent set of data on oil
         content and related properties on effluent and influent samples
         taken on a regular schedule from ten separate, offshore platforms
         for ten consecutive days.

     The oil content variability is demonstrated by the ranges of effluent oil
contents, of soluble fractions, and of dispersed oils.

     2.  One restriction limited the realization of the second objective to
determine the factors affecting brine oil content variability.  The platforms
were to be studied as they were usually operated.  Nevertheless, this objec-
tive was satisfied in part.  For example, simple statistical analysis identi-
fied soluble oil as a significant variable platform-to-platform, and brine
surface tension as a significant variable on any platform.  Variations in
operating conditions (such as influent oil content, excursions in influent
oil content, interruption of flotation chemical, and hydraulic loading)  pro-
duced notable changes in effluent brine oil content.  But no simple statisti-
cal correlations were developed.

     3.  A comparison of gravity separator effluent oil content with the 5-
to 120-minute values of the susceptibility to separation test indicated  that
the equipment was generally operating near those values.  Equipment design
and operation within the design limits must also be considered in assessing
separator performance.   A comparison of flotation influent and effluent  oil
content showed that the flotation units reduced the oil content further, and
reduced it below the limit for gravity separators indicated by the suscepti-
bility to separation test.  Most flotation units were effective in removing
dispersed oil, but their removal efficiencies differed.

     4.  Special adaptations of six test methods contributed to the success-
ful accomplishment of the project objectives:

         a.  The infrared method for measuring oil  concentrations in brine
             proved to  be acceptable for on-site determinations.  Although it
             gives different results from the gravimetric method, the two are

                                     11

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             correctable  on  a  platform-by-platform  basis.

         b.   The silica  gel/Infrared  method  for  oil  and  grease  analysis  pro-
             vided a measure  of the soluble  oil  content.   The soluble  oil
             content at  the discharge conditions is  a  lower  limit  of treat-
             ability by  gas flotation.

         c.   The equilibration  method measured brine-soluble components  of
             the crude oils.   Results using  this method  are  of  the same  order
             of magnitude  as  those obtained  by the silica  gel/infrared method.

         d.   The test for  susceptibility  to  separation proved to be a  useful
             semi-quantitative  tool in estimating the  ease and  ultimate  limit
             of gravity  separation.

         e.   The filtered  brine method was intended  to provide  a measure of
             soluble oil plus finely  dispersed (under  10 um) oil in the
             effluent.  As such, it could provide an alternative to the
             silica gel/infrared method in establishing  a  lower limit  of
             treatability  for flotation processes.   Differences in experi-
             mental procedure caused  this method to  be inconsistent with the
             infrared method  for determining oil  and grease  in  some cases.

         f.   Using unique  new equipment,  oil  drop-size distributions were
             obtained from photomicrographs  for  both flotation  unit influents
             and effluents.  These measurements  determined the  size range-of
             dispersed oil droplets removed  by gas flotation.   Dispersed oil
             concentrations calculated from  these distributions compared
             poorly with measured infrared oil concentrations.

     Based on the experience  of this  project, the first  four methods can be
used to characterize produced brine.   Also,  the  filtered brine  method, after
suitable modification, appears  promising. The photomicrograph!c method  has
application  in verifying mathematical models and in  improving equipment  design,

     5.  Flow rate data  adequate for  the  minimum needs of  this  project were
obtained through a combination  of ingenuity  and  considerable effort on most
platforms.  However, the research value of this  data set would  have been en-
hanced by a  reliable, portable flowmeter.
                                     12

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                                  SECTION 4

                               RECOMMENDATIONS
SCOPE

     The recommendations given here are restricted to those which advance the
three specific objectives of this study with the potential of incrementally
improving the technology used today.

BACKGROUND

     The present project has provided an extensive collection of high quality
data which potentially could be used to answer many questions concerning the
nature of oil in water and water treating processes.  This data base is so
large and comprehensive that a major effort will be required to realize its
full potential.   Produced water treating systems are so complex that a more
comprehensive analysis of these data is needed in order to avoid duplication
and waste in future work.

     One subject that has already been clearly demonstrated to be important
in the present work is the type of compounds making up oil in water.

     Bulk oil in the stock tank is composed largely of paraffinic, naphthenic
and aromatic hydrocarbons with trace amounts of other organic compounds in-
cluding polar compounds.

     The present study found that the flotation influent and effluent contain
large quantities of polar organic compounds which adsorb on silica gel.

     The study further indicates that the flotation influent and effluent
contain organic compounds dissolved in the water phase and dispersed as
droplets.

     Simultaneous increases in oil content and decreases in brine surface
tension suggest that some polar compounds are surface-active agents.  These
may be concentrated at the oil/water interface between the water phase and
oil droplets.

     The equilibration test indicates that water in contact with oil in the
formation over geologic time contains dissolved compounds, most of which are
polar.  Flotation effluents probably contain substantial organic compounds
which originally were in the dissolved state in the formation.
                                      13

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     Reducing the total  oil  content in discharges involves all  three types of
organic compounds, bulk dispersed oil, surface-active species at the interface
and dissolved compounds.

SPECIFIC RECOMMENDATIONS

     1.  A comprehensive analysis of the data base provided by  the present
project must be undertaken.   This analysis should include a multivariant
analysis of the treatment processes (gravity separation and flotation).   The
results of the analysis should identify the significant variables affecting
the stabilization of oil-in-water and of process unit performance.  These
variables should be ranked in importance.  Possible shortcomings of the
various variables should be  pointed out (such as limited range  of hydraulic
loadings in the present work, limited data on variation of chemical treating
concentrations, ...).  Missing variables of potential importance should  be
identified (gas to water ratio in the flotation process, ...).   No other
field studies of treatment processes should be undertaken until  this work
is complete and its recommendations are known.

     2.  Methods for characterizing oil in water beyond simply  measuring its
concentration should be investigated.  Some obvious candidates  are (1)  GLC-
boiling point distribution curves such as the method used in the present
study to characterize the bulk oil; (2) GLC-MS; and, (3) infrared spectroscopy.
Those methods which prove useful  could be used to do a parametric study  of
bulk oils and extracts from a range of water discharge points.   Parameters
should include:  (1)  type of solvent for extraction (Freon, polar, nonpolar,
...); (2) pretreatment of sample (bulk separator effluent, gravity separator
effluent, flotation cell effluent, ...-all both with and without silica  gel
treatment); (3) acidification (samples studied as function of naturally  .
occurring pH and with acidification to various predetermined levels); (4)
type of chemical treatment given the water (some samples with added chemical
treatment and some analyzed  as is).

     One specific recommendation is to examine the saved Freon  extracts  from
the present project as recommended by the analytical subcontractor after
Phase I using the GLC boiling point method and to try and correlate the
results with the present data base.

     3.  Two methods subject to problems during the present study (filtered
brine oil in water, flow rate) need more study.  The filtered brine method
should be modified to be as  near as possible to the infrared oil in water
method except for the water filtration step prior to extraction.  Then  this
method should be used on a number of discharge points to see if problems
encountered in the present study persist.

     A search should be conducted for a reliable portable continuous flow
rate meter.  Process studies are hampered by the lack of a reliable tool for
determining this potentially important variable.
                                     14

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                                 SECTION 5

                               PROGRAM PLAN


OBJECTIVES

     The objectives of the overall program were:

          ... To characterize the brines discharged from offshore platforms
              with respect to oil content,
          ... To identify the factors contributing to oil content of the
              brine, and
          ... To consider approaches to reduce brine effluent oil content.

     The program was planned to be conducted in two phases so that Phase I
experience could be used to revise the Phase II Plan.  A specific objective
for Phase I was to develop recommendations for Phase II.

BACKGROUND INFORMATION

     An'EPA sponsored study (1) by Exxon Research and Engineering Company
identified the oil content of produced brine as the most important parameter
to control and proposed a plan to develop a pollution control rationale for
offshore oil  and gas production.

     Previous surveys (2,3) have demonstrated that there are wide variations
in oil content of brines from different platforms and of the brine from a
single platform at different times.  A general conclusion (3) has been that
brine oil content is more directly related to brine characteristics, degree of
emulsification, droplet size, suspended solids concentration, and other
factors than to the sophistication of the treatment system.   A limitation of
previous surveys has been that little information on factors contributing to
oil content has been available for correlation with measured oil contents.

     An earlier EPA report (4) concluded that gravity separation followed by
dissolved gas flotation represented Best Demonstrated Technology.

TECHNICAL APPROACH

     The approach to meeting the program objectives was to conduct ten-day
field surveys on ten platforms, three during Phase I and seven during Phase II.
A major part of the testing was directed to defining the variability of brine
effluent oil  content.  Special tests were run to determine whether the oil in
the brine was soluble, dispersed in fine droplets, or associated with sus-
pended solids.  Information on the design and operation of the water treating

                                     15

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systems was recorded for correlation with brine oil content test data.

     The field survey testing schedules were developed in a step-wise manner.
Before the program was started, the EPA Program Officer developed a preliminary
program plan based on the Exxon draft report (1).  The Exxon report and the
preliminary program plan included a generalized schematic of an offshore pro-
duction system, Figure 1.  As a guide, the preliminary plan identified sam-
ple points and the tests to be run at each sample point.   One requirement was
to run forty oil  content tests by the gravimetric procedure and forty by the
infrared procedure on the brine effluent from each platform.

     The preliminary plan recommended the analytical  procedures to be used.
The procedures and the general significance of each are discussed in later
paragraphs in this section.

     Three platforms were selected for Phase I survey testing to represent a
variety of conditions with respect to water cuts, lift methods, processing
schemes, chemical addition, difficulty of treatment and polishing units (type
of flotation unit).

Platform Selection

     The objective in platform selection was to pick platforms representing a
wide spectrum with respect to factors considered to have the most influence
on effluent oil content.  The factors chosen for highest priority were brine
treatability, gravity separator type, and flotation unit type and hydraulic
loading.  Other factors considered were lift method, water cut, character-
istics of produced fluids, processing systems, and chemical addition programs.
Platforms with flow monitors were selected if other criteria were met.

     Following is a listing of technical criteria used for platform selection:

                — Treatability
                -- Lift method
                — Water cut
                -- Process complexity
                -- Chemical addition
                -- Gravity separator type
                -- Flotation unit type
                — Flotation unit hydraulic loading

     A non-technical criterion was that platforms selected have living
quarters.  Meeting testing schedules would be much more difficult and expen-
sive if the survey team could not stay on the platform.  One of the ten survey
platforms did not have quarters.

     Before selecting platforms for the survey, fifty-five were reviewed
based on information provided by the operators.  Information on higher
priority selection criteria are listed in Table 8 for all platforms con-
sidered.  The platforms selected for Phase I and Phase II surveys are listed
at the top.  One platform, EI175C, selected for the Phase II survey became
unavailable for operational reasons and was replaced by Platform SM130B.

                                      16

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                                               18

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     All  data in Table 8 are preliminary planning estimates and do not nec-
essarily match conditions at the time of the survey as presented in other
parts of the report.  The brine treatability ratings are operators estimates
based on field experience.  The ratings in Table 1 are based on this survey
test results for soluble oil, the more soluble oil the more difficult to
treat.  Both rating methods are empirical.  In both cases there is a good
balance between platforms with easy, medium and difficult to treat brine.

     Gravity separators of three types and flotation units with five different
design variations were included in the survey.  The range of hydraulic loading
of flotation units selected was from 9 to 84 percent of design rating.

Location and General Information

     All of the platforms considered for the survey were in the Louisiana Gulf
Coast area.  Figure 2 is a location map.  To illustrate diversity, one
platform, SM130B, was over 140 kilometers from shore and had been in produc-
tion less than two years.  Another platform, BDCCF5 was in a marshy area and
had been in production about twenty-five years.  BDCCF5 was the only platform
without quarters.

     All platforms selected were producing oil, gas, and water.  The number
of wells producing oil per platform varied from one to thirty at the time of
the survey.  The locations of the survey platforms are shown in Figure 2 in
relation to important areas of production.

     The platforms studied were located where the large hydrocarbon accumula-
tions were mostly associated with salt domes or anticlines overlying various
salt masses (5).

     The Bay Marchand-Timbalier Bay-Caillou Island salt dome complex is more
than 47 km long and 7 to 20 km wide with 3 domes derived from a common
Triassic-Jurassic salt.mass penetrating to within 600-1000 meters of the sur-
face and forming a variety of associated traps in sandstones of Pliocene to
to Miocene age.

     Eugene Island, South Pass, South Timbalier and West Delta are other major
offshore oil or gas accumulations with Tertiary sandstone reservoirs.  Practi-
cally all known types of traps occur in connection with salt dome structures
(6).  These include:

     1.  One simple domal anticline.
     2.  Graben fault trap over dome.
     3.  Porous cap rock of limestone or dolomite.
     4.  Flank sand pinchout and sand lens.
     5.  Trap beneath overhangs.
     6.  Trap uplifted and buttressed against salt plug.
     7.  Unconformity.
     8.  Fault trap downthrown away from dome.
     9.  Fault downthrown toward dome.

     The characteristics of produced fluids from other locations and other

                                      19

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formations may be different from those included in this survey.  Little infor-
mation is generally available on the amount of soluble oil and surface active
compounds present in the brine from various locations and formations.  It is
known that there are differences that could have a significant effect on oil/
water separation.

Operational  Characteristics

     In addition to analytical testing, the program plan included collecting
available information on produced fluids and on the design and operation of
production facilities to evaluate for correlation with brine oil  content.   The
characteristics of produced fluids, chemical usage, design and operating
conditions of the processing system, and upsets and intermittent operational
procedures were of special  interest.

     A general but more detailed list of the types of information to be re-
corded is as follows:

     	Well  Data	  	Processing Data	

     Formation identification           For vessels design and operating
     Total vertical  depth
     Production rates                   Flow rate
       Oil                              Temperature
       Water                            Pressure
       Gas                        .      Residence time
     Water cut                          Overflow rate
     Lift method
     Lift gas                           Chemical  addition
     Shut in bottom hole pressure
     Flowing tubing pressure            Upsets
     Choke size
     Gravity of oil                      Intermittent operational  or
     Receiving vessel                      maintenance procedures
     Chemical injection                 Unplanned events


     Information on  the above factors was to be obtained by observations and
measurements by the field survey team, from company records,  and  by verbal
reports from operating personnel.

ANALYTICAL TEST METHODS

     Standard analytical test methods were employed for a majority of the  test-
ing program.   Procedures published by the U. S. Environmental  Protection Agency,
American Society for Testing and Materials, American Public Health Association,
American Petroleum Institute and special  procedures adapted for this program
were used.

     Table 9 presents a listing of parameters  measured, method(s) used and
applicable references.  The complete procedure for each test  is presented  in
this report  in Appendix A.   The purposes  of the tests and field experience


                                      21

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                      TABLE  9.   ANALYTICAL  TEST  METHODS
Parameters
Surface Tension
Viscosity
Crude Oil Solubility
Susceptibility to
  Separation
Ionic Analyses
  Sodium, Potassium
Iron, Calcium
  Magnesium
  Barium
Chloride, Sulfate
Total Dissolved Solids
Sulfide
Alkalinity
Bacterial Culture
Particle Size
  Distribution
     Method
Surface Tensiometer
Viscometer
Silica Gel Adsorption
Equilibration
Filtered Brine
IR Scan
Infrared

Flame Emission

Atomic Absorption

Autoanalyzer
Gravimetric
lodometric Titration
Electrometric Titration
Sulfate Reducing

Photomicrographic
     Reference
                                                                         (1)
Oil & Grease

Temperature
pH
Boiling Range
Distribution
Specific Gravity
Water Cut
Suspended Solids
Infrared (Storet 00560)
Gravimetric
Thermometer
Combination Electrode
Gas Chroma tography
Hydrometer
Volumetric
Gravimetric
EPA
EPA
ASTM
ASTM
ASTM
ASTM
ASTM
EPA,
ASTM
     ASTM
     ASTM
     APHA
Shell Oil Company
Mobil Oil Corp.
     EPA
 Conoco,  Inc.

     API

     EPA
     API
     APHA
     EPA
     APHA
     API
     API

  Section 16
(1)  More detailed references in Appendix A.
                                      22

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with them are discussed in a following subsection.

Oil and Grease Determination - Infrared

     Total recoverable oil and grease determinations were made onboard the
platforms according to U. S. EPA procedures substituting a Horiba OCMA-200
IR analyzer for the EPA recommended double-beam recording IR spectrophotometer.
The Horiba instrument was a portable non-dispersive IR analyzer especially
suited to work on offshore platforms.  Linearity in the concentration range
0-100 ppm (V/V) was verified prior to use of the equipment offshore.

     Analysis of brine was accomplished by acidification with HC1 or
H2S04 to pH 2, extraction three times with 30 ml Freon TF, filtration of the
Freon through Whatman 40 filter paper and IR analysis of the Freon extract.
Preliminary oil and grease data were reported in yl oil/1 brine (ppmv).  Con-
centrations were converted to mg oil /I brine using specific gravity data.

Oil and Grease Determination - Gravimetric

     Samples of brine were also extracted for analysis of total  recoverable
oil and grease by gravimetric techniques.  Separate brine samples were pro-
cessed on the platforms in a manner identical to IR samples.  The Freon
extracts were returned to the onshore laboratory in glass bottles sealed with
teflon-lined screw caps.  Samples were transferred to round-bottom evaporation
flasks.  The Freon was stripped off using a 70°C water bath.  The contents
were dried in an 80°C water bath, and N2 was used to purge the flask of
remaining solvent.  The flasks were cooled in a desiccator for 30 minutes and
weighed.  Gravimetric oil and grease concentrations were reported in mg oil /I
brine.

Temperature

     Temperature measurements were accomplished utilizing dial  thermometers
calibrated against mercury thermometers.   Since system temperatures were
usually higher than the ambient air temperatures, this technique did suffer
somewhat from inaccuracies in temperature equilibration under non steady state
conditions.  However, the error limits are estimated to be ± 0.75°C.
     Measurement of pH was accomplished utilizing a Type 1 battery-operated
pH meter (ASTM, 1978).  The response of the combination electrode was verified
every second day.  The electrode was replaced whenever the response slope was
less than 95 percent of the Nernst slope.   The battery powered pH meters
proved to be less reliable than desired.   Error limits of ± 0.5 pH units are
likely to exist.

Crude Oil Boiling Range Distribution

     Crude oil  samples were collected onboard each platform for a determination
of the boiling range distribution.  Samples were returned to the laboratory
and analyzed by gas chroma tography.   Initial  boiling point (IBP), final

                                      23

-------
boiling point (FBP), and cumulative area percent for each 50°C interval from
IBP to FBP were reported for each sample.

Specific Gravity

     Crude oil and brine specific gravities were measured using hydrometers
conforming to ASTM design.  Readings were taken as soon as possible after the
sample was collected to ensure that specific gravity data reflected applicable
system conditions.  Temperature data were also taken.

Water Cut

     Determinations of the percent water and sediment in produced fluids were
made according to ASTM D 1796-68 (1973) without modification.

Suspended Solids

     Suspended solids data were generated following the EPA Storet Method
No. 00530 using Gelman A glass fiber filters.  Quality control  techniques
according to ASTM Standard Test Method D 1888-67 (1974) were employed.
Samples were collected onboard the platforms using inline filter holders to
prevent oxidative production of suspended solids.  Volumes filtered ranged
from 50-1000 ml  depending on where the samples were collected in the system.
After the samples were taken, all filters were washed with 50 ml  of deionized
water, removed from the filter holder, and placed in clean plastic petri
dishes.  The dishes were placed in the onboard freezers until all  platform
work was completed, subsequently transported to the TI Dallas laboratories on
ice and stored in laboratory freezers until analysis.  Results  (mg/1) were
reported as total suspended solids, total Freon-soluble material,  total acid-
soluble material  (6NHC1), and residual suspended particulate material.

Surface Tension

     Crude oil and brine surface tension measurements were made according to
ASTM Standard Test Method D 1590-60 (1977) utilizing Fisher Scientific Company
Model 20 Tensiometers.  Fisher Vibradamp^B balance supports were also used to
ensure low vibration operation.  As employed, these vibration dampers
eliminated machinery-associated platform vibration so that representative
surface tension measurements could be made.  Temperature was measured but not
controlled.  The measured surface tension was adjusted to the surface tension
at the sampling temperature by the Othmer relation (10).  When  tests were run
on samples taken upstream of the flotation unit, the free oil was  removed by
static settling in a separation funnel before the surface tension  test was
run.

Silica Gel Adsorption

     Measurements to determine adsorbable hydrocarbons in Freon extracts on
2 percent deactivated silica gel were made according to APHA Standard Method
502E, Hydrocarbons (7).  Oil and grease determinations were performed using
the Horiba IR analyzer, as previously described.  Results were  reported as
concentration of the remaining hydrocarbons (mg/1) after adsorption.

                                      24

-------
Crude 011 Equilibration

     Equilibration tests were run by a procedure supplied by Shell Oil Company
which is presented in Appendix A.  A layer of crude oil was placed on top of
a layer of brine in a 4,000 ml flask so that the two layers were not mixed.
The flask was then held in an oven at 82°C for fourteen days.  A sample of
the brine was then taken for an IR-Oil content measurement.  For Phase I tests
a synthetic brine equivalent to a concentration of 100,000 mg/1 was used.  The
oil/water volume ratio was four oil to one water.

     For Phase II testing, the brine concentration was the same as that of the
produced brine of the particular platform.  One equilibration test was run with
the same oil/water ratio as the produced fluids.  A second test was run with
a 4/1 oil/water ratio.

Filtered Brine

     Water samples were filtered through Whatman No. 40 filters to remove
large dispersed oil droplets.  Soluble oil and some of the finely dispersed
oil would pass through the filter.  According to the 1979 Fisher Scientific
Co. catalog (pp. 321), the Whatman 40 filter removes particles of about 8-ym
size.

     After filtering, the filtrate was analyzed for filtrable hydrocarbons
following the previously discussed technique for IR determination of oil and
grease.

     Following are differences in the filtered brine and the standard IR-Oil
test for oil and grease:

     1.  Sample volume:

            Filtered Brine Test - 50 ml
            Standard IR-Oil Test - 1000 ml

     2.  Sample/Freon Extract Ratio:

            Filtered Brine Test - 50 ml sample/50 ml Freon
            Standard IR-Oil Test - 1000 ml sample/90 ml Freon

     3.  Filtering of Freon Extract Before Measuring Absorbance:

            Filtered Brine Test - Freon not filtered.
            Standard IR-Oil Test - Freon filtered.

IR Scan of Addition Chemicals and Freon Extracts

     Infrared scans of addition chemicals and selected Freon extracts were
made using a Perkin-Elmer Model 621 scanning infrared spectrophotometer.
Addition chemicals without water were run using 0.1 or 0.05 millimeter cells
or salt plates.  In the case of addition chemicals in water solution, the
water was evaporated from the sample using a heat lamp, the residual  material

                                       25

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was incorporated into a KBr pellet and the scan was made.  All scans were run
from 4000-550 cm-1.  Attenuation was adjusted so that the largest peak in the
scan remained on scale.

Viscosity

     Crude oil viscosity measurements were made following ASTM Standard Test
Method D 445-74 using calibrated Cannon-Fenske viscometers.  For each crude
oil sample, the kinematic viscosity was determined experimentally and the
dynamic viscosity was calculated using crude oil densities taken at the same
temperature as used for determining viscosity.

Susceptibility to Oil Separation

     The susceptibility to separation (settling) tests were run by a procedure
supplied by Conoco Inc.  Several samples were taken each in a different
separatory funnel.  The brine oil  content was then measured after various
defined settling times.  The IR-Oil test previously described was used.  For
Phase I testing, the settling times were 1, 5, 15, 30, 60 and 120 minutes.

     For Phase II testing the settling times were 2, 5, 15, 30, 60 and 120
minutes.  Zero-settling-time control  samples were taken immediately before and
after taking the settling test samples.

Standard Oilfield Ionic Analysis

     Table 9 presents the methods for the analysis of major constituents in
oil field waters.  Standard methods were utilized throughout for flame emis-
sion and atomic absorption spectrophotographic analyses.  The atomic absorp-
tion analyses were made using a flame source for calcium and magnesium; iron
and barium analyses were made using a heated graphite atomizer source.  Stan-
dard addition analyses, blank and background corrections, and spiked sample
analyses were conducted for each determination.

Bacterial  Culture:  Sulfate-Reducing  Bacteria

     The technique for determination  of sulfate-reducing bacteria follows the
alternative technique (API RP 38)  for estimating sulfate-reducing bacteria.
Sample bottles with the nutrient agar and acid-etched iron mails were prepared
and autoclaved in the laboratory.   Bottles were again sterilized immediately
prior to use so that the agar would be liquid and mixing of the inoculum could
be done.  Bacterial samples were held onboard the platforms in portable in-
cubators set within 5°C of the recorded temperature of the brine water at the
time of sampling.  Samples were transported to the TI Dallas laboratories
in insulated containers.  The incubation continued for a total of four weeks
in laboratory incubators.   All  bacterial  samples were prepared in duplicate.
Results were reported as a range in numbers i.e., 100-1000 sulfate-reducing
bacteria per milliliter.

Particle Size Distribution

     Particle-size distribution tests were run by a new non-standard procedure

                                      26

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which is described in Section 16.  Brine samples were taken from a flowing
stream into a cell where the flow was stopped just long enough to take photo-
micrographs of the particles present.  The procedure has the capability to
distinguish between solids, oil  droplets, and gas bubbles.

     For Phase II testing, a sample of the brine from the photomicrograph test
unit was taken during each run for oil content tests.  This was not done
during Phase I.

PURPOSES OF TESTS AND FIELD EXPERIENCE

     Each test used had a purpose in meeting the Program objectives.  All the
tests were either for measuring brine oil content or for measuring parameters
that could influence the oil content.

     Test development work was not included in the Program Plan.  For the most
part, standard tests were used and they proved effective in meeting the Pro-
gram objectives.  Problems were experienced with certain tests in the field
that limited their value.  The major tests and the tests with which problems
were experienced are discussed in this subsection.

Standard Oil Content Tests

     The standard infrared and gravimetric oil content procedures were used
to determine the level and variability of brine oil content.  These procedures
were completely satisfactory for the intended purposes.

IR-Oil w/Silica Gel Test

     The IR-Oil w/Silica Gel test was used as an indicator of polar water-
soluble-type compounds in the brine.  Various investigators (7,8,9) have shown
that hydrocarbon oils in Freon are adsorbed on silica gel only to a very
limited extent, whereas naphthenic acids, vegetable oils and other polar
compounds having significant water solubility are adsorbed under the test
conditons.  To the extent that the IR-Oil w/Silica Gel test is a true
indicator of solubility, it is also an indicator of a lower level of treata-
bility by physical processes.  The IR-Oil and corresponding IR-Oil w/Silica
Gel tests were run on the same Freon extracts.  The term "soluble" oil is
used in this report for the material extracted by silica gel.  The term
"dispersed" oil is used for the unextracted material.

     When applied to flotation unit effluents with IR-Oil contents typically
less than 100 mg/1, the IR-Oil w/Silica Gel tests indicated that the amount
of "soluble" oil present was relatively uniform from sample to sample on each
platform.  This consistency, which was expected, enhanced the confidence that
could be placed in the test results.  The IR-Oil w/Silica Gel test was con-
sidered very useful in indicating the proportion of "soluble" oil and "dis-
persed" oil in effluents.

     During Phase II only, the IR-Oil w/Silica Gel test was run on samples
taken upstream of the flotation  unit.  The IR-Oil contents were typically
above 100 mg/1 and fluctuated widely from sample to sample.

                                      27

-------
     The filtered brine IR-Oil tests on upstream samples on most platforms
indicated less soluble oil was present than was indicated by the IR-Oil
w/Silica Gel tests.

     Because of conflicting data, no attempt is made in this report to draw
conclusions about differences in soluble oil in the brine at different points
in the production systems.  The IR-Oil w/Silica Gel test data and the filter-
ed brine test data on the flotation effluent and at upstream sampling points
are presented in a single table for comparison in each individual platform
section.

IR-011  Filtered Brine Test

     The IR-Oil filtered brine test was used as an indication of treatability.
Brine was filtered through Whatman No. 40 filter paper.  Then the IR-Oil  con-
tent of the filtrate was measured.  Only soluble oil  and very fine droplets
were expected to pass through the filter.

     The filtered brine survey test results were not always consistent with
the IR-Oil  results.   The mean oil  content of flotation effluent filtered
brine was higher than that of unfiltered brine for five platforms.   For one
platform, the mean oil content of filtered brine was 30 mg/1 higher.  The mean
oil content of flotation effluent filtered brine was lower than that of un-
filtered brine on the other five platforms.  For one platform,  the mean
filtered brine oil content was 63 mg/1 lower.

     A possible explanation for high filtered brine oil content is that the
Freon extract of some brines retains a water haze.   If the filtered brine test
procedure were revised to include filtering the Freon before IR analysis, the
procedure would be more comparable to the standard IR-Oil  test.

     The filtered brine test is discussed more fully in Section 18.   Because
of apparent inconsistencies in the filtered brine test results, the data were
examined only in a cursory manner in relation  to brine IR-Oil  content.

     The filtered brine test results were consistently less  than the IR-Oil
test results, as would be expected, when the dispersed oil  content  exceeded
about 15 mg/1.

Susceptibility to Separation

     The purpose of  the susceptibility to separation  tests  was  to provide a
quantitative measure of the rate of separation of oil  from brine by gravity.
Field experience demonstrated that there are significant differences in oil
separation rates of different brines.  As previously discussed, brine oil
contents were measured after settling times from 0 to 120 minutes in separatory
funnels.

Particle-Size Distribution

     Small  oil  drops are more difficult to separate from brine  than large
drops.   The particle-size test used provided a measure of the number of oil

                                      28

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drops of each micron size (in the 2-120 um range) in a calculated volume of
brine.  Tests were obtained on nine platforms.

     The drop-size measurements were also used to calculate the concentration
of dispersed oil.  These calculated oil concentrations generally did not check
well with oil content as measured by standard procedures.  The particle-size
tests are discussed in Section 16.

Infrared Scan of Freon Extracts

     Infrared scans of Freon extracts were run to identify functional groups
in the material measured as oil.  A special interest was whether or not
addition chemicals were contributing to effluent oil content.

     The IR-scan tests gave a qualitative indication that carboxylic acid
groups were present in the Freon extracts of the brine of the three Phase I
platforms.  The test did not provide a positive indication of the presence
of addition chemicals.  The IR-scan tests were not continued for Phase II
testing.

Suspended Solids Tests

     Oil coated solids are a potential contributor to brine oil content.  Sus-
pended solids tests were run to permit examining the theory that there is a
correlation between brine suspended solids content and brine oil content.

     As the Program progressed, it became apparent that the precision of the
suspended solids test as applied in the field was limited.  The apparent
cause was retention of variable amounts of salt on the filters.  This problem
is discussed more fully in Section 18 with a study of the amount of water
washing of the filters required to improve the precision of the test.

     Because of the limited precision of the suspended solids test, the data
was analyzed only in a cursory manner.

DATA EVALUATION AND PRESENTATION

     The primary purposes of the data evaluation were to describe the effluent
oil content data base provided by the survey testing and to determine which
other parameters correlated with the effluent oil content.  The analytical
test results for each platform are presented in a separate section as
follows:

     Phase I                                Phase II
     Section 6, SP65B                       Section 9, BM2C
     Section 7, WD45C                       Section 10, ST131
     Section 8, ST177                       Section 11, BDCCF5
                                            Section 12, SS107
                                            Section 13, SS198G
                                            Section 14, EI18CF
                                            Section 15, SM130B

                                      29

-------
The particle-size distribution test results are presented in Section 16.
Comparisons between platforms are presented in Section 17.

     All test results obtained during the survey, without exception, are
presented in the appropriate data tables.  A small number of test results
were excluded from statistical analysis, but only for one of three reasons.
When test results were excluded from analysis, then a footnote is always pro-
vided below that data table.  This note states why that value was excluded.
The three reasons for excluding data from analysis are:

     1.  Test results representing a system upset caused by conducting the
survey were not included in the data analysis.  A guideline of the program
was that no changes in operations were to be made for the survey.  The systems
were to be evaluated as they typically operated.  Twice the survey team
interrupted the addition of water treating chemical.   Six effluent sample
periods were affected on one platform and one sample  period on another.  Once
the operator caused a flotation unit upset in the process of installing a
flow monitor for the survey.  One effluent sample was affected.

     2.  When observation indicated a probable testing error, the result was
not included.  For example, salt crystals were observed in the residue after
evaporation of Freon for the gravimetric oil content  test of five samples
during the survey.

     3.  A total of six effluent oil  content test results were not included
in the data analysis based on the subjective opinion  that they were in error
because of inconsistency with other test results.

     The primary statistical parameters used in evaluating the data were means
and standard deviations.  Some linear least squares regression models were
tested and some frequency distributions were plotted.  The following symbols
are used in presenting the data:

     n  = Number of samples
     x  = Sample arithmetic mean
     s  = Sample standard deviation using (n-1) sample weighting
     r  = Linear regression correlation coefficient

     A  = Mean difference in paired values

     s. = Standard deviation of paired values

     Certain data samples were compared as paired values.  The IR-Oil and
GR-Oil test results were compared in this manner as well  as in terms of sample
means and standard deviations.  The samples for the tests by the two oil con-
tent procedures were taken about one minute apart from a  flowing  stream.  There-
fore, the comparisons include time-dependent sample differences as well as
normal sampling and testing variations.

     Paired values were also used as one basis for comparing flotation unit
influent and effluent oil content test results.  The  paired samples were taken

                                      30

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only a few minutes apart.   However, each flotation unit had a significant
residence time.  Time-dependent sampling differences would be important.   Even
so, with steady operations the paired comparisons are of interest.

     In the following sections, the survey test data are displayed in tables,
time-indexed plots, histograms, and linear regression plots.
                                      31

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                                  SECTION 6

                               PLATFORM SP65B
GENERAL
     Platform SP65B was the first on which tests were conducted.   A ten-day
test program conforming closely with the approved program plan was started on
June 13 and completed on June 22, 1979.

     A detailed description of the production facilities, the test program,
and data presentation and evaluation are provided in this section.

     Four survey team members arrived at the platform by helicopter with a
Company engineer about Noon on June 12 and were immediately given a safety
briefing.  Field test equipment arrived by boat about 1600 hours  and was un-
loaded and set up, so that sampling and testing could start the following
morning.  Oil company personnel assisted in every possible way in unloading
equipment, and providing work space, sample taps, utilities and living
quarters.

     There were no disruptions of the test program during the ten days caused
by weather or operational problems.

FACILITIES AND OPERATIONS

Production From Wells

     At the  time of the survey, 30 wells were producing an average of
1,218 m3/d (7,658 bpd) of crude oil, 643 m3/d (4,045 bpd) of water, and
329,270 std  m3/d (11,635 Mcfd) of gas.  These averages are based on well test
data.

     Two wells producing 69 m3/d (432 bpd) of oil but no water flowed by
reservoir pressure to a medium-pressure two-phase separator.   The oil  flowed
from the medium-pressure separator to a low-pressure manifold.  Six wells
producing 292 m3/d (1,835 bpd) of oil and 1.1 m3/d (7 bpd) of water flowed
by reservoir pressure to the low-pressure three-phase separator.   Production
from 22 wells producing 857 m3/d (5,391 bpd) of oil, and 642 m3/d (4,038 bpd)
of water was gas lifted to the low-pressure separator.

     Combined flow to the low-pressure separator of 1,218 m3/d (7,658 bpd) of
oil and 643 m3/d (4,045 bpd) of water was equivalent to a water cut of 35
percent.


                                     32

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     Seventy percent of the oil was gas lifted, and 99.8 percent of the water
was gas lifted.

     Measured production for the ten-day period averaged 1,184 m3/d (7,447
bpd) or 2.8 percent less than was indicated by well test data.

     Chemicals are not used downhole on SP65B.  Also, no well work over opera-
tions were conducted during or shortly before the survey that would affect the
characteristics of the produced fluids.

Production Process System

     The flow of oil and water through the system is shown in Figure 3.
Design and operating data on major vessels are presented in Table 10.  The
primary oil/water flow is to the low-pressure three-phase separator, also
called a free water knock out (FWKO).  Five to six percent of the oil  flows
through a two-phase medium-pressure gas separator before entering the low-
pressure separator.

     About 99 percent of the water drops out in the free water knock out.
The oil flows to the electrostatic oil treater where the water content is
reduced to less than 0.5 percent.  The crude oil  then flows to a storage tank
to be pumped to a pipeline for sale.

     A demulsifier, Nalco 4400, is added continuously at the rate of 11 dm3/d
to the low-pressure manifold.  A biocide, Champion DQ61, is added continuously
at the rate of 4 dm3/d also to the low-pressure manifold.

     The purpose of the facilities discussed to this point is the production
of saleable crude oil and gas.

     Figure 4 is a flow schematic for the water handling system.  The pur-
pose of this system is to prevent the loss of oil from the platform and to
treat oily water to a satisfactory level  for discharge.   A nominal  average
water flow balance is presented in the figure.  Some of the flows are
estimates.  More detailed flow and flow-variability data are presented in a •
following subsection.

     The primary produced water flow is from the  free water knockout to the
skim tank (gravity separator), to the flotation unit, and then to discharge.
Other water flows to the skim tank are from the oil treater, from a closed
sump receiving flotation froth and miscellaneous  drains, and from the skim
pile.

     All oily water flows, or is pumped to the skim tank for gravity separa-
tion of oil.  The major continuous flow is from the free water knock out.
There are also continuous flows from the oil  treater, and the froth flow from
the flotation unit.

     Drains from most potentially oil contaminated areas flow to the closed
sumps.  The two pumps in the closed sumps operate on level  control, but one
pump runs continuously.

                                     33

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                                      A H> SEA
                   FLOW ELEMENT


SIMPLE POINT    — — — INTENUITTENT FLOW
NOTE' HK KPAIU«« SAI NOT IN lERVItZ AND
   HOT MOWN
                            Figure  3.   Flow diagram,  production process  system,  SP65B.

-------
                                        TABLE 10.  SP65B Vessel Data  Sheet
to
en

5A2 " "•
Medium pressure
gas/liquid
Vessel description separator
Trade Name or Vessel Type Horizontal
Cylinder
Design Parameters
Dimensions, n, (ft)(*)
Diameter, O.D.
Length. S.S.
Length
Width
Height
Surface Area. «Z, (ft2)
Separation Total
Per Cell
Separation Volume, n3. (bbl)
Total
Oil Phase
Water Phase
Number of Cells
Flow Rate. »3/day. (bpd)'2*
Overflow Rate Per Cell, (m3/d)/»2.(bpd/ftV3*
Recycle Rate, Percent of Flow
Retention Time. min.
Average Operating Parameters
Temperature. °C(°F)
Pressure. kPag, (psig) 4.206(610)
Flow Rate. m3/d (bpd)'2*
Flow Rate, Percent of Design
Overflow Rate Per Cell. (m3/d)/m2.(bpd/ft?)
Recycle Rate. Percent of Flow
Froth Flow, Percent of Flow
VESSEL DESIGNATION
5A3 	
Low pressure
3-phase
separator
Vertical Cylinder
Cone-Bottom

4.27(14)
14.3 (154)
14.3 (154)
6.5 (41)
33.4 (210)
-
-
-
40(104)
593(86)
637(4.005)
45(26)
-
-
ON FLOW DIAGRAM -
6
Oil treater.
cltem
electric
Horizontal
Cylinder

3.66(12)
10.67(35)
-
7.3 (46)
-
-
-
40(104)
207(30)
6.4 (40)
;
.
-
FIGURE 6-1
8
Gravity
separator,
skim tank
Rectangular
Tank

11.43 37.5)
3.96 13)
9.14 30)
45.3 (488)
45.3 (488)
328(2.064)
-
-
-
38(100)
0(0)
955(6.006)
21(12.3)
-
-

9
Flotation unit.
mechanical ,
dispersed gas
Wemco
Model 84

6.92(22.7)
1.86(6.1)
12.91(139)
3.25(35)
17(107)
4
6.135(38.585)
1.888(1.102)
-
4
39(102)
0(0)
655(4.120)
11
202(118)
-
46
(1) Tank dimension only.
(2} Water flow rate.
(3) Overflow rate is surface area divided by flow rate.

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                                            SKIM  TANK
                                                                     FLOTATION  UNIT
co
                  FLOTATION  AID
      FROM FWKO
FROM  OIL
 TREATER


FROM SKIM
   PILE
                   ( 5A30  J
                   (  6__0
                     I3__0)
U&
                                                                                         C  9--0)
                                              TO
                                             SEA
                               WATER       5A30   6	0   13	0   9F   9_ _l  9_ _0
                               FLOW  m3/d    63T     *      l2     S00   955    655
                                     bpd   4009   40     75    1886   6O06  4120
                              Figure 4.   SP65B water handling system flow schematic

-------
     The skim pile receives drainage intermittently from areas that may be
oil contaminated.  Curbed areas flow to the skim pile during rains.  It did
not rain during the test period.  Sand collected in the bottom of the skim
tank is also drained to the skim pile.  Water or oil  is pumped from the skim
pile by a gas lift pump.  The pump operates on a timer, 6 seconds out of every
55 seconds or about 11 percent of the time.  The flow rate is estimated at
12 m3/d.  Oil was not observed to be present in the water returned from the
skim pile during the ten-day test period.

     A water treating chemical, Nalco 8AF542, is added continuously to the
skim tank influent at the rate of 11 dm3/d.  This system is unique in that the
coagulant chemical which enhances the flotation process is added ahead of the
gravity separator rather than just ahead of the flotation unit.

     The skim tank is a large rectangular vessel.  Figure 5 is a dimensional
sketch of the skim tank and also shows probable flow patterns.  Water enters
the tank at a depth of 6.6 m through two inlet distribution pipes extending
the width of the tank.  Water flows through evenly spaced 1.9 cm x 3.8 cm
holes on each side of the pipes.  The inlet distributors function to disperse
the water uniformly in the upper part of the tank and develop a laminar, non-
turbulent downflow in the primary gravity separation zone of the tank.  Three
outlets are located at 1.2 m depth, 5.3 m below the inlets.

     At an average flow rate of 955 m3/d (6,006 bpd), the average holding
time is 8.2 hours.  The average flow rate in terms of surface area is 21
(m3/d)/m2(12.3  bpd/ft2).

     The skim tank is a well designed gravity separator.  It is conservatively
sized for the flow it receives.  The actual performance is compared to expect-
ed performance in a later section of this report.

     The skim tank has sloped bottom sections to permit draining accumulated
sand.  Drain details are not shown on the drawing.  Oil drain details also
are not shown.

     The polishing unit is a proprietary four-cell dispersed gas flotation
unit (Wemco 1+1, Model 84) as shown in Figure 6.  Gas dispersion is by
mechanical eduction.  Oil separation is by skimming a froth over side weirs
in each section.  The rated flow is 6,135 m3/d (38,585 bpd) with a holding
time in each cell of one minute.  The manufacturer recommends this unit for
especially difficult oil/water separation jobs.  The unit operates with a
gas blanket to exclude air.

     The average effluent flow from the unit was 655 m3/d (4,120 bpd) or only
about 11 percent of the design flow.  The unit operated with froth overflow in
the range from 17 to 86 percent of the effluent flow.  This is higher than a
normal froth overflow of about 5 percent but should contribute rather than
detract with respect to effective oil separation.

     A general  conclusion is that the combined skim tank-flotation system is
conservatively designed.
                                      37

-------
CO
00





3.81
m _^ 3.81 m _,. 3.81 m


1
2.59m
r r n
/-INLETS-"
—OUTLETS^-



~— -x
1 ¥ Vi
4.57m I 3.96m 1
— 	 , 	 mj~* 	 . 	 mJ 1
         
1.83m-1
  1.22 m-
                                   TOP  VIEW
                            die
                        .
                                  SIDE   VIEW
                                                            INLET  DISTRIBUTORS, 15.2 cm
                                                            DIAMETER  WITH 1.9cm x 3.8 cm
                                                            SLOTS ON  EACH SIDE  25.4 cm
                                                            APART.
                                                            15.2cm OUTLET NOZZLES
                                                                 m
                                                               WATER  VOLUME = 328m3
                                 Figure 5. SP65B skim tank sketch.

-------
to
10
                                                                                           LIOJIO LEVEL
                                                                                            CONTROLLER
                                                  ^- FBOTH OUTLET



                                                SIDE VIEW
                                                                                                                   L '	INTERNAL

                                                                                                                        MOTOH
                                                                                                          END VIEW
                                               Figure  6.   SP65B flotation unit sketch.

-------
SITE SPECIFIC TEST PROGRAM

     The planned test program for major brine samples is presented in Table
11.  The number of samples to be taken in ten days and the time the samples
are to be taken each day are listed.  The listed program was carried out with
only minor variations as will be observed later.  A limited number of tests
were run at minor sampling points not shown in Table 11.

     In addition to the brine tests, the following tests were run on crude oil
samples:  temperature, specific gravity, viscosity, boiling range distribution,
equilibration, and surface tension.

     Particle size distribution measurements were not obtained on SP65B.
Field application equipment problems, and limited operator experience were
the reasons.

OPERATIONAL DATA AND OBSERVATIONS

     The types of data to be collected and the purposes were discussed in
general terms in Section 5.  Measurements, records, and observations for the
ten-day survey period on SP65B are reported in this subsection.

Flow Monitoring

     A major effort was made to obtain a continuous record of flow of the
polishing unit effluent, by use of the clamp-on ultrasonic monitor purchased
for this purpose.  All efforts failed.  The monitor had been checked out on-
shore.  The manufacturer's service representative worked with the unit on the
platform, and could not tell whether it was an equipment problem or an appli-
cation problem.

     On the seventh day of the test program, an orifice plate flow meter with
recorder was placed in service on the skim tank outlet, which is also the
flotation unit inlet.  Three days of hourly average, minimum, and maximum flow
are charted in Figure 7.

     The hour-to-hour flow rates are relatively uniform, and the average daily
rates are very uniform.  However, differences in hourly minimums and maximums
are wide compared to average flows.

     In considering short-term flow variability, it should be noted that the
flow is controlled by a dump valve.  The dump valve operates from a high
level sensor in the skim tank.  Flow was fluctuating on one-minute cycles
over a 110 to 160 m3/d range.  For example, if the average one-minute flow
was 820 m3/d, the range could be from 740 to 900 m3/d.  Further, a 110 m3/d
difference in average flow from one 15-minute period to the next was not
uncommon.

     The flotation unit effluent flow rate can be calculated by subtracting
the froth recycle flow from the influent flow.

     The froth flow rate was calculated from the time required to fill a known

                                      40

-------
                               TABLE 11.   SP65B  TEST  SCHEDULE  FOR THE  MAJOR BRINE  TESTS
SAMPLE POINTS
9--0
No. of Tine of
tests tests
V
9-i
No. of Tine of
tests tests
V
8--1
No. of Time of
tests tests
V
6--0
No. of Tine of
tests tests
5A30
No. of Time of
tests tests
field Tests
  Infrared Oil
  Temperature
  pll
  Water Specific Gravity
  Water Surface Tension
  IR-Oil W/Silica Gel
  IR-OII Filtered Brine
  Susceptibility to Separation
 (1)  Field scheduled.
40
20
10
10
10
20
10
8.10.13.I
   8.10
    10
    8
    6
   8.13
    8
40   8.10.13,15
10      10
20
10
8.13
 10
20
10
8.13
 10
20
10
13
10
                                                                                                                                         (1)
Laboratory Tests.
' Gravimetric oft
Suspended Solids
Ionic Analysis
Bacterial Culture
Particle Size Distribution
IR-Scan of Freon Extracts
40
10
1
1
3
1
8. 10.13.15
15
I)
in
(1)
20
10
I
~t
J
8.13
15
(I)
(1)
10
1
15
(1)
i (i)
20
2
1
8.13
15
(i)
                                              NOTE:  Some of  the one-a-day samples were not scheduled
                                                    for a certain hour and are listed at the time
                                                    actually run.  Time of tests listed is by
                                                    military hour.

-------
   50-
   40-
UJ
*
o
_J
u.
   20
   IO-,
       -ZOO
       -ISO
       -IOO
       -90
                                                                                                         - 8O
              1
       HOUR  4


       DAY
                                                                                                    200-
                                                                                                         - 40
                                                                                                    I5O-
                                                                                                         -3O
                                                                             IOO-
                                                                       ONE HOUR



                                                                      MAXIMUM



                                                                      MEAN 	
                                                                                                         -20
                                                                                                     5O-
                                                                                                         -10
                                                                      MINIMUM
                                                                                                       E

                                                                                                       a.
     t     I     I
                              II    I
                                                                                            1     I
12


B
16    20    24    4    8
12


9
16    20   24    4
12


10
                                                                                       16   20   24
                              Figure 7.  Flow chart SP65B skim tank effluent.

-------
volume of the froth overflow launder when the drain valve was closed at least
twice per day.

     Table 12 shows calculated flotation unit effluent flows:

                  TABLE 12.  SP65B AVERAGE WATER FLOW DATA

Day
08
09
10

Skim tank
effluent
834(153)
845(155)
850(156)
24-hour average flow m3/d
Froth
136(25)
169(31)
202(37)
(gpm)
Flotation
effluent
698(128)
676(124)
649(119)
Mean                    844(155)              170(31)            674(124)
     The three-day average effluent flow rate of 674 m3/d includes an esti-
mated 12 m3/d from the skim pile.  The produced water flow was 643 m3/d
estimated from well test data.

     The three-day average froth flow of 170 m3/d is below the overall average
for the survey.   The range of all froth flow rate measurements was 109 to
564 m3/d and the average was 300 m3/d.

Well Test Data

     Production tests were run on each of the 30 producing wells either dur-
ing or shortly before the survey test period.  The test data as provided by
the operator are presented in Table 13.

     The well test data table includes:

          Well number                     Lift gas rate
          Formation                       Shut in bottom hole pressure
          Total  vertical depth            Flowing tubing pressure
          Gas production rate             Choke size
          Oil production rate             Oil gravity
          Water production rate

     The well data are separated in the table according to lift method, and
also according to which separator received the production from each well.
The well test data were used in developing the average oil and water pro-
duction rates and water balance previously presented.

     All 30 wells flowed continuously during the ten-day survey period.  The
close check between oil production calculated from test data and measured oil
production, 1,218 m3/d (7,658 bpd) and 1,184 m3/d (7,447 bpd), respectively


                                      43

-------
                                               TABLE  13.    SP65B WELL  TEST DATA
Well
FonRation
                           TVO
                           ft
                              Gas
                              HEW
                                                     on
                       Water
                       "Epd~
                      lift gas
                       Hcfd
                                                                              Pressure,
                       SIBIIP
             FTP
            Choke size
             1/64
                                                     *1«
                                                     In.
             API  gravity
flowing to Medium Pressure Separator
B-41          G1RB
B14A          G3RA
Total  (Average)
                 7.254
                 7.317
  217
1.062
1.279
192
240
432
0
0
0
2.461
2.001
800
800
14
19
 30.0
 28.9
(29.5)
flowing to low Pressure Separator
B-7-
B-7D
B-8-
B20-
B-21
827-
Total
G1RA
G-RA
H4RB
G1RA
G1RA
G1RG
(Average)
Gas Lift to Low Pressure
fl-i-
B-2-
B-2A
B-3A
8)0-
Bll-
B12-
B1S-
B15D
BUD
B18-
B190
B22D
B23-
8230
825-
B25D
826-
B28-
B30A
B31E
8330
Total
G3KA
G3RB
G2RC
H4RB
H-RC
G3RA
G3RO
G2RB
G1RB
G1RA
G3RA
G2RA
G2RE
G1RA
G1RA
G3RA
G2RA
G-RF
G1RG
GIRC
G1RB
H-RO
(Average)
.
7.240
7.361
7.253
7.253
7.308

Separator
7.273
7.156
7.115
7.353
7.205
7.330
7.420
7.450
7.300
7.237
7.294
7.313
7.130
7.302
7,255
7.295
.
7,285
7.185
7.160
7.320
7.440
5.110
336
317
474
1.303
558
2.258
5.246
330
299
160
384
171
39
207
335
105
654
202
117
537
145
116
319
142
78
227
112
71
360
5.110
317
326
136
238
610
208
1.835
738
218
95
445
69
92
353
75
330
651
404
287
348
239
303
68
102
78
37
149
121
194
5.391
                                                                  7
                                                                 158
                                                                 154
                                                                  0
                                                                  0
                                                                  39
                                                                 431
                                                                 111
                                                                 177
                                                                  7
                                                                  0
                                                                 123
                                                                  0
                                                                  80
                                                                 130
                                                                 609
                                                                 409
                                                                  6
                                                                  0
                                                                 596
                                                                 224
                                                                 777
                                                              4.038
                                                                              0
                                                                              0
                                                                              0
                                                                              0
                                                                              0
                                                                              0
                                                                              0
                                                                125
                                                                622
                                                                530
                                                                387
                                                                250
                                                                403
                                                                553
                                                                335
                                                                454
                                                                130
                                                                357
                                                                339
                                                                258
                                                                539
                                                                220
                                                                412
                                                                369
                                                                 97
                                                                132
                                                                351
                                                                651
                                                                460
                                                              7.974
                                                                             2.604
                                                                             2.604
                                                                             2.604
                                                                             1.493
                                                2.001
                                                1.986
                                                2.442
                                                2.001
                                                2.638
                                                2.292
                                                2.461
                                                2,604
                                                2.150
                                                2.001
                                                1.414
                                                2.604
                                                2.604
                                                2.001
                                                2.001
                                                1.797
                                                1.493
                                                2.440
                                                2.461
                                                             480
                                                             500
                                                             240
                                                             900
                                                             500
                                                             250
                                                 300
                                                 140
                                                 130
                                                 180
                                                 110
                                                 110
                                                 150
                                                 350
                                                 150
                                                 700
                                                 300
                                                 110
                                                 250
                                                 200
                                                 450
                                                 120
                                                 110
                                                 100
                                                 120
                                                 120
                                                 140
                                                 250
                                                                16
                                                                14
                                                                22
                                                                20
                                                                26
                                                                48
                                                   29
                                                   64
                                                   44
                                                   56
                                                   64
                                                   56
                                                   56
                                                   27
                                                   40
                                                   25
                                                   26
                                                   54
                                                   30
                                                   38
                                                   19
                                                   54
                                                   50
                                                   56
                                                   56
                                                   56
                                                   56
                                                   44
                                                                  31.5
                                                                  31.5
                                                                  28.4
                                                                  29.6
                                                                  29.4
                                                                  28.6
                                                                  (29.8)
                                                                                                                                    29.0
                                            29.3
                                            29.3
                                            30.6
                                            34.3
                                            29.6
                                            30.5
                                            28.3
                                            28.5
                                            29.6
                                            29.3
                                            29.6
                                            30.
                                            28.
                                            29.
                                            28.
                                            28.
                                            27.
                                            28.
                                            28.
                                            30.
                                            29.4
                                           (29.5)
Combined Total (Average)
                            11.635
          7.658
          4.045
        7.974
                                           (29.5)

-------
lends credibility to water production estimates based on the test data.

Vessel Pressures and Temperatures

     The pressure of each oil/water separation vessel was recorded  twice per
day.  The temperature was recorded once per day based on the temperature of
an effluent sample.

     Table 14 presents pressure and temperature ranges for the  ten-day
period.

	TABLE 14.   SP65B VESSEL  TEMPERATURES  AND PRESSURES	

                              Pressure,
                                kPag                       Temperature,
Vessel                         (psig)                           °C

Medium Pressure               4,140-4,240
Separator                      (600-615)

Low Pressure                    580-610                    37.7-40.5
Separator                       (84-88)

Oil Treater                     200-214                    36.5-41.8
                                (29-31)

Skim Tank                          0                       35.4-39.6
                                  (0)

Flotation Unit                     0                       35.5-39.8
                                  (0)
     Table 14 indicates steady operation of all vessels in narrow temperature
and pressure ranges for the ten-day period.

Pressure Drops Through System

     Table 15 traces pressure drops from the producing formation through the
system.

     Table 15 shows that the greatest pressure drops occur from the formation
to the chokes, substantial drops occur at the chokes, and more minor drops
from the chokes on.  The data in Table 15 includes only the wells producing
water.

     The pressure drop data are tabulated to permit evaluation of the theory
that pressure drops at chokes and valves may form small-particle oil dis-
persions that are difficult to remove in separation equipment.


                                      45

-------
                TABLE 15.   SP65B  PRESSURE DROPS  THROUGH  SYSTEM
Location
Pressure,
   kPag
  (psig)
    Pressure drop,
point or description
Pressure drop,
    kPag
   (psig)
Formation
(SIBHP)
Flowing Tubing
Pressure
Low Pressure
Separator
Skim Tank
10,290-18,190
(1,493-2,638)
   690-4,830
  (100-700)
   580-610
   (84-88)
    perforations,
    static head,
    pipes

    chokes,
    valves,
    pipes


    control valve,
    pipes
 8,570-17,150
(1,243-2,488)
   100-4,240
   (15-615)
   580-610
   (84-88)
Chemical  Addition

     Three chemicals were added continuously by small  metering pumps as list-
ed below in Table 16.

     The water treating chemical  was added ahead of the skim tank and may have
enhanced both gravity separation and flotation of oil.
                     TABLE  16.   SP65B  CHEMICAL ADDITION
Chemical
              Addition
               point
                     Addition rate
                     dm3/dppmv
Champion DQ 61
(Biocide)
Nalco 4400
(Demulsifier)
Nalco 8AF542
(Water treating
 chemical)
            Low pressure
            separator inlet
            manifold

            Low pressure
            separator inlet
            manifold

            Low pressure
            separator
            outlet
                      11
                      11
      17
      17
                                                                      (1)
                                                                      (1)
(1)  Based on average volume of water discharged from the flotation unit.
                                      46

-------
     The chemical feed rates were checked twice per day by observing the pump
down rate in a gauge glass for one minute.  This is not a highly precise
measurement but does confirm that the chemicals were being added at approxi-
mately the intended rate.

     The chemicals were added uniformly and continuously, except that the feed
pump for the water treating chemical was not functioning when sampling started
at 0800 hours on the first day.  The problem was malfunction of a check valve.
The pump was repaired and put in service at 1600 hours on the first day and
functioned for the rest of the ten-day period.

Observations and Operator Reports

     An effort was made to record any event that could affect effluent oil
content.  The operators were requested to provide information on upsets and
intermittent operational or maintenance procedures, and the survey team made
their own observations.

     All 30 wells produced continuously for the ten days.  Most of the wells
were diverted to the test separator for a few hours but the fluids were dumped
to the low-pressure separator as they would have been during normal produc-
tion.  There were no major upsets.

     The following are comments on observations and non-routine events.

     The flotation unit was opened and inspected from two to several  times
each day.  In every case, there was a good froth layer which was being skimmed
effectively.

     The water from the skim pile was regularly inspected and was never
observed to contain oil.  On Days 8, 9 and 10, the skim pile water had an
anerobic sulfide-type odor and hazy appearance.  It was suspected that
draining sand from the skim tank may have seeded the skim pile.

     On Day 1, the water treating chemical feed pump was not functioning as
previously noted.  The effect is discussed in the data presentation section.

     On Day 1 and Day 2, the oil content in the skim tank inlet was high.
Any of the four makeup streams—the freewater knock out, the oil treater, the
closed sump, or the skim pile--could have been the source, but the actual
source was not identified.

     On Days 2, 3 and 10, intermittent water-level-control fluctuations were
experienced with the oil treater.  This could result in discharging high oil
content water to the skim tank, but analytical tests did not confirm a prob-
lem.

     On Day 8, one of the two sump pumps was taken out for repairs.  The other
pump was adequate to handle the full flow.

     Detergents were not used for washdown during the survey.
                                      47

-------
     There was no flow contribution by rainfall during the survey.

     In general, operations were uniform with respect to factors that would
be expected to change the quality of the water discharged.

DATA PRESENTATION AND EVALUATION

     Comprehensive data tables and summary tables and graphs are interspersed
in the text.

Effluent Oil Content

     Table 17 presents a listing of all oil content test results.  Figure 8
presents a plot of GR-Oil content in and out of the flotation unit versus
time for the ten-day period.  Figure 9 presents the same plot for IR-Oil
content.

     The graphs show an erratic pattern of higher oil content values for the
first six samples taken, four the first day and two the second day.  The test
values for the remaining eight and one-half days are in a narrow range at a
lower concentration.  The flotation aid chemical was not being added most of
the first day and several hours were required to establish effective oil
separation after chemical addition was restarted.  The flotation influent and
gravity separator influent oil content values were also comparatively high
during the same period.  The reason was not determined.  The high effluent
oil content values on Day 1 and Day 2 appeared to be caused by loss of
chemical addition and other undetermined factors.

     The ranges of test results are as follows:

     Flotation Effluent GR-Oil - 39 to 552 mg/1,
     Flotation Effluent IR-Oil - 57 to 448 mg/1,
     Flotation Influent GR-Oil - 70 to 482 mg/1,
     Flotation Influent IR-Oil - 91 to 692 mg/1.

     Flotation unit effluent oil content histograms for the two test methods
are presented in Figure 10 and Figure 11.  Figure 12 is a regression plot of
effluent GR-Oil versus IR-Oil.  In comparing oil content test results by
the two methods, it should be remembered that the samples were taken about
one minute apart from a flowing stream.  Therefore, the comparisons include
time-dependent sample differences as well as normal sampling and testing
variations.

     Table 18 presents a summary comparison of test results by the two
methods.

     As expected, the mean by the IR-Oil method is higher.  Only one GR-Oil
test result exceeded the paired IR-Oil result.  The substantial standard
deviation for paired tests indicates that there is not a uniform difference
in paired tests.
                                      48

-------
TABLE 17.  SP65B MAJOR BRINE TESTS



IP separator
effluent (5A30)


Sample time GR-01) IR-OI 1
Day Hour mg/1 mg/1
01 08J
01 10
01 13
01 15*
02 08
02 10
02 13
02 15
03 OS
03 10
03 13
03 15
04 08
04 10
04 13
04 IS
05 08
05 10
OS 13
05 IS
06 OS
06 10
06 13
06 IS
07 OS
07 10
07 13
07 IS
08 OS
08 10
08 13
08 IS
09 08
09 10
09 13
09 15
10 08
10 10
10 13
10 IS
Minimum
Maximum
1.354 1.544
, '
- -
- 1.044

575
-
659 905
.
936 1.131
-
859 922
-
652 1.022
-
922 1.131
.
566 739
-
559 739
-
631 705
-
534 635
-
876 979
-
828 765
.
553 600
-
453 644
-
639 644
.
426 652
-
422 522
_
533 744
-
422 522
1.354 1.544
(1) The flotation chemical
(2) Based
on well test data
Oil treater
effluent (6--0)


IR-OH
ng/1
457

174
.
774
_
165
.
1.783
-
261

483
-
174
-
217
.
2.435
.
296
-
226
-
418
.
187

348
.
122

165

413
-
404

374
-
122
2.435
Gray, separator
influent (8—1)


IR-Oi]
«KJ/I
96.000

52.188
_
23,920
_
82.631
.
1.131
.
565
-
839
.
922
_
1.566
.
1.218
.
774
-
957
.
778
.
2.392

739
.
591

2.783
.
2.653
-
3.131

2.870
-
565
96.000
feed pump was running, but was not


(A) Not included in data analysis. Appears inconsistent with
Flotation unit
Influent (9--1)


GR-Oi) IR-Oil
•9/1 1*3/1
482 631
692
441 578
400
124 370
144
93 122
117
111 122
126
113 130
139
109 135
122
106 126
126
91 113
104
93 113
113
99 104
104
119 96
130
92 104
113
91 139
113
113 122
113
105 130
130
70 100
91
89 104
113
78 104
144
72 100
109
70 91
482 692





Flotation

IR-Oil w/sillca

unit

gel




effluent (9--0)
Filtered
brine
GR-Oil IR-OH Dispersed Soluble IR-Oil
•9/1 "9/1
183 270
294 374
390 448
224 300
SO 66
48 391
54 63
57 62
85 70
52 66
50 67
49 70
57 70
58 70
£3 73
63 73
63 73
57 66
70 81
56 66
52 58
43 59
48 57
46 63
47 63
44 64
59 67
49 64
67 77
52 81
61 84
552(A) 86
45 77
53 81
519(A) 76
45 80
52 70
42 76
61 75
39 71
39 57
552 448
pumping. Test results are Included


other GR-Oil. IR-Oil, and "soluble"
•9/1
191

331
.
12

7
_
6
.
5

7
_
9
_
16
.
21
.
7
.
10
-
9
_
12

19
.
31

22
.
20
-
14

18

5
331
•9/1
79

117
_
54

£6
_
64
.
62
_
63
.
64
-
57
-
60
-
51
.
47
-
54
-
55
.
56
.
53
-
55
-
56
-
56
_
57
-
47
117
mg/1
57
.
.
.
43
.
.
.
152
.
_
.
71
.
-
.
69
-
-
.
64
-
.
-
70
.
-
_
65
-
.
-
62
-
-
-
75
.
.
-
43
152

Surface
tension
dynes/ca
43
_
-
.
68
.
.
.
71
-
.
.
73
-
.
-
66
-
-
-
72
-
-
-
72
•
-
-
70
-
-
-
71
-
-
-
65
-
-
-
43
73

Flow
OutiZp
•3/d
655
655
655
655
655
655
655
655
655
655
655
655
655
655
655
655
655
655
655
£55
655
655
655
655
655
655
655
655
655
655
655
655
655
655
655
655
655
655
655
655
_
~

rate
Skimmings
*3/d
.
.
-
-
-
.
-
.
-
-
.
-
564
564
564
564
202
202
365
365
409
409
447
447
262
262
332
332
109
109
158
158
136
136
202
202
202
202
202
202
109
564
In data analysis.

oil tests.

-------
      80O-
      700-
      600-
      500-
OR-OIL
  mg/l
      400-
      30O-
      200-
       IOO-
                                               ^EFFLUENT
                                                   5        6
                                                       DAY
                      Figure 8.   SP65B flotation unit performance, GR-oil  vs  time.

-------
             eoo-
en
     IR-OIL

      mg/l
            7OO-
             600-
             5OO-
4OO-
            3OO-
             2OO-
             IOO-
                                                         " EFFLUENT
                  2    '   3    '    4    '
                                                         5    f    6    '    7
                                                            DAY
10
                               Figure 9.  SP65B flotation unit performance, IR-oil vs time.

-------
  30-
        iiiii|ii!i(Tiiiiiirr i   i  i   i  r
  20-
O
z
UJ
D
cr
                                   n- 33
                                   1*77

                                   s»73


                                   I OF 38 VALUES IN MEAN OVER 300 mg/l
                      TI
                                                  n         n
                                                            IT
                  50
            00
 I  I
ISO
                                                      200
                                             I   1
                                            2SO
                                     GR-OIL, mg/l


         Figure  10.   SP65B flotation unit  effluent,  GR-oil  histogram.
  30—
TIII   i  r i  I  T  i  T  i  i   i
                                                            i  r  i  i
                                                                           i  r
$2 20-
UJ
3

s   -
jf 10-
                                   n »40
                                   T» 1O6

                                   «* 99

                                   4 OF4Q VALUES IN MEAN OVER 3OO m«j/1
                                                                        n
                i  r
                  50
         Fiqure 11.
 i   i  i
 ISO
                                   i   i  i   i
                                     2CO
                                                                 i  i
                                                                  2SO
 1  I   I  I   I  I  I
        100

               IR-OIL, mq/1


SP65B flotation unit effluent,  IR-oil  histogram
                                       52

-------
              2OO-
              150-
cn
co
     GR-OIL

       n»Q/l   loo-
               50-
                     T   I   I   I   I   I   I   I   I   I   I   I   I  I   I   I   I   I   T
                         GR-OIL=II+0.6I( IR-OIL)

                              r=0.84


                         11% OF DATA INCLUDED IN  EQUATION OFF GRAPH
                      I   I   I   I   I   I   I   I   I   I   I   I  I  I   I  I   !   l   I   I   I   |  I   I   I   I   I   I   T
                   )              50             100             ISO             200             250

                                                           IR-OIL.mg/l


                   Figure 12.  SP65B flotation  unit effluent, infrared-gravimetric  regression.

-------
                  TABLE  18.   SP65B  FLOTATION  UNIT  EFFLUENT
                         GR-OIL AND  IR-OIL  COMPARISON



Number of tests, (n)
Mean, (x), mg/1
Minimum, mg/1
Maximum, mg/1
Standard Deviation, (s) , mg/1
Oil content
GR-Oil IR-Oil
38 40
77 106
39 57
552 448
73 99
Number, (n)
Mean of Differences,  (A), mg/1
Standard Deviation,  (s.), mg/1
Paired tests

    38
    32
    56
     All test results for dispersed oil and soluble oil as measured by the
IR-Oil w/Silica Gel test are listed in Table 17.  A summary of these test
results is presented in Table 19.

      On average, 62 percent of the oil in the effluent was  soluble  oil and
38 percent was dispersed oil.


                    TABLE 19.   SP65B  SOLUBLE OIL SUMMARY

Analysis or test
IR-Oil
Dispersed Oil
Soluble Oil
Flotation effluent
Range Mean
mg/1 mg/1
57-448 99
5-331 38
47-117 61
Proportion
of total ,
percent
100
38
62

Note:  Table  includes only  IR-Oil  tests when an  IR-Oil w/Silica  Gel  test was
       run.   The mean of 99 mg/1  is  lower  than the mean  of  106 mg/1  for  all
       IR-Oil tests.


      Linear regression  plots  of  dispersed  oil versus  IR-Oil  and  GR-Oil  are
presented  in  Figure  13.  Extrapolating the linear  regression lines  to zero
dispersed  oil indicates a residual  IR-Oil  of 54  mg/1  and a  residual  GR-Oil
of  43 mg/1 would still  be present in the brine after  all  dispersed  oil  is
removed.
                                      54

-------
        140—
        120-
        100-
         80-


TOTAL
  OIL
 tnq/I
         60H
         40-
         20-
              I  I
II  I   I  I   II   1  I   il  1   t  i   1  I   I  1   I
• TOTAL IR-OILVS   DISPERSED IR-OIL
TOTAL  IR-OIL*54+1.2 (  DISPERSED  IR-OIL)
r = 1.0

• TOTAL QR-OJL VS  DISPERSED  IR-OIL
TOTAL  SR-OIL* 43 + 0.97 ( DISPERSED  IR-OIL)
r » 0.98
 10%  OF DATA  INCLUDED IN EQUATIONS OFF GRAPH
   TOTAL IR-OIL- DISPERSED IR-OIL
                                   TOTAL <3R-0«L-  DISPERSED  IR-OIL•
               i  r  i  r  i     r  r  i
              0            10
                                  DISPERSED   IR-OIL,  mq/
                Figure 13.   SP65B flotation unit effluent,
                   total oil  -  dispersed oil  regression.
                                     55

-------
Surface Tension

     All surface tension test results are reported in Table 17.  The mean
surface tension of the flotation effluent is 67 dynes/cm.

     Nine of the ten flotation effluent surface tension test results were in
the range of 65 to 73 dynes/cm.  The other result was 43 dvnes/cm.
The lowest value occurred on Day 1 when the chemical  was not feeding and the
effluent oil content was above average.  The linear regression equation for
effluent IR-Oil and surface tension is:

               IR-Oil = 550 - 6.9 (Surface Tension)
                    r = -0.96

     The regression equation indicates a significant decrease in oil content
with an increase in surface tension.  The one lowest surface tension value
corresponding to the highest oil content value predominated in establishing
the slope of the linear regression line.

Suspended Solids

     Suspended solids test data are presented in Table 20 for major sam-
pling points.

     A suspended solids summary for SP65B is presented in Table 21.

     A substantial portion of the solids at all sampling points were Freon
soluble.  Forty-seven percent of the solids in the flotation effluent were
Freon insoluble solids of which 65 percent were acid soluble.

     Figure 14 presents time-indexed plots of Freon insoluble suspended
solids in the flotation influent and effluent, and of flotation effluent
dispersed oil.  The suspended solids samples were taken at 1500 each day
and the dispersed oil samples were taken at 0800 and 1300 each day.

     The plotted data do not demonstrate a distinct pattern that the dis-
persed oil content of the effluent is higher when flotation influent or
effluent suspended solids are higher.

Filtered Brine

     The filtered brine IR-Oil content of SP65B effluent was in the range of
43 to 152 mg/1 with a mean of 73 mg/1.  The mean IR-Oil content of un-
filtered brine on SP65B was 89 mg/1 for all samples when filtered brine tests
were also run.

     For comparison to the effluent mean filtered brine IR-Oil of 73 mg/1,
the soluble oil mean was 61 mg/1.

Flotation Unit Performance

     Figure 15 is a regression plot of IR-Oil in and out of the flotation

                                     56

-------
                                      TABLE 20.  SP65B SUSPENDED SOLIDS TESTS
en
-vl

Gravity separator,
Sample tine
Day Hour
01 15
02 15
03 15
04 15
05 15
06 15
07 15
08 15
09 15
10 IS
Minimum
Maximum
Total
SgTT
221
120
108
146
162
189
76
106
187
107
76
221
Freon
soluble
•HJ/ 1
139
95
86
106
130
159
66
87
150
88
66
159
Freon
Insoluble
«9/T
82
25
22
40
33
30
10
19
37
19
10
82
In (8-1)
Acid
soluble
WQ/ 1
40
10
13
32
22
28
3
12
18
9
3
40
Flotation unit. In
Fixed
igTT
42
15
8
9
11
2
7
7
19
10
2
43
Total
igTT
114
64
63
84
97
129
51
175
117
74
51
175
Freon
soluble
mg/T
88
45
45
39
51
68
37
160
79
53
37
160
Freon
Insnliihlg
26
19
18
45
47
61
14
15
39
21
14
61
(9--1)
Acid
soluble
wg/1
2
7
8
11
17
11
12
8
26
12
2
26
Flotation unit, out (9--0)
Fixed
igTT
24
12
9
35
30
50
2
a
13
9
2
50
Total
«gTT
92
25
21
46
28
IB
12
36
51
32
12
92
Freon
soluble
51
6
14
23
16
10
8
26
20
20
6
51
Freon
insoluble
41
19
7
23
10
8
4
10
31
14
'4
41
Acid
SQlubi.e
21
14
6
10
7
5
5
8
26
7
5
26
Fixed
igTT
20
4
2
14
3
3
0
2
5
£
0
20

-------
                  TABLE 21.  SP65B SUSPENDED SOLIDS SUMMARY
                                       Average suspended solids,  mg/1
Suspended Solids                       8—i        9—i          9—0
Total
Freon Soluble
Freon Insoluble
Acid Soluble
Fixed
142
111
32
19
13
97
67
31
11
19
36
20
17
11
6

Note:  Some numbers do not check exactly because of rounding.

unit.  The regression plot indicates there is a significant correlation  in
flotation influent and effluent oil  content.   The high oil  content values
occurring on Day 1 and Day 2 predominate in establishing the relationship.
Except for those on the first two days, all other influent  and effluent
brine oil content values are in narrow ranges.

     The flotation unit was operating at about 11 percent of design capacity.
This low hydraulic loading may have been a factor in smoothing out fluctua-
tions in effluent oil content.

Skim Tank Performance

     The skim tank (gravity separator) effluent and the flotation unit
influent are the same.  Therefore, all data for the flotation  influent (sam-
ple point 9—i) also characterize the skim tank effluent.

     Skim tank in and out oil content data are presented in Table 17.   The
influent is highly variable.  The effluent IR-Oil content mean was 170 mg/1,
with a standard deviation of 147 mg/1, and a range of 91 to 692 mg/1.

     The time-indexed plots in Figure 8 and Figure 9 labeled "influent"
represent skim tank performance.  The first four to six oil content tests are
relatively high (IR-Oil 631, 692, 578, 400, 370 and 144 mg/1).  As previously
noted, this occurred when coagulant chemical was not added  ahead of the skim
tank and the influent oil content was comparatively high.  The remaining test
results  indicate consistent performance.

     For comparison to  the skim tank effluent oil content,  the mean oil  con-
tent after sixty minutes  settling under susceptibility-to-separation test
conditions was 211 mg/1.

Miscellaneous Brine Tests

     All other brine  test results for  SP65B  are  listed  in Tables 22, 23, 24,
25,  26 and 27.  The  results for the  following tests were in narrow ranges  for


                                     58

-------
         T
    ISO
 Ol
 E
z"
o
    100
lit
O

8
    so
     o  -
                          _L
                        INFLUENT S.S.
JL
 -EFFLUENT DISPERSED OIL

J	I	I	L
J_
                     2         3         4         56         7         6

                                                     DAY

                  Figure  14.   SP65B flotation unit Freon  insoluble suspended  solids.
                                                               to

-------
cr»
o
        500-i
        300-
      O
      i
      1U
a.
u.
ui
      2 200—
      O
                        I  I  I
                         IR-OILoul* 16* 0.13 . (IR-OIL in)

                                i - 0.79
                                                                              I  I  I  |  I  I  I   I  I  I  I  I  _
                    I  I  I  I  I  I  I  I  I     I  I   I  I   I  I   I  I   I  I  I   I  I
                        100         260          300          400         9OO
                                                                      I   I  I   I  I   I  I  I  I  I  II T
                                                                               660
700
                                      FLOTATION UNIT  INFLUENT IR-OIL, mg/l


                            Figure 15.  SP65B  flotation unit in-out IR-oil regression.

-------
TABLE 22.   SP65B SUPPLEMENTARY BRINE TESTS

Sample
Day
01
01
02
02
03
03
04
04
05
05
06
06
07
07
03
08
09
09
10
10
Mean
time
Hour
08
10
08
10
08
10
08
10
08
10
08
10
08
10
08
10
08
10
08
10

Minimum
Maximum
Temperature, °C
13--0
_
25.5
-
25.5
-
26.5
-
25.7
-
25.8
-
26.7
-
27.0
-
26.6
-
26.2
-
26.2
26.2
25.5
27.0
14--0
„
32.7
-
30.8
-
29.5
-
30.2
-
31.5
-
32.5
-
32.2
-
34.1
-
38.6
-
38.5
33.1
29.5
38.6
5A30
^
39.0
-
37.7
-
38.5
-
40.0
-
40.0
-
40.5
-
39.5
-
39.8
-
40.3
-
39.8
40.0
37.7
40.5
6--0
.
39.1
-
36.5
-
27.5(A)
-
39.5
-
40.3
-
40.5
-
41.8
-
41.5
_
40.5
-
41.2
40.1
36.5
41.8
8-i
M.
38.1
-
36.0
-
38.0
-
39.5
-
39.8
-
39.5
-
38.8
-
40.3
-
39.9
-
39.8
39.0
36.0
40.3
9--i
w
35.4
-
36.5
-
37.2
-
37.7
-
39.0
.
38.7
-
37.2
-
39.5
-
39.6
-
39.0
38.0
35.4
39.6
9--0
35.5
38.0
37.7
37.8
37.0
37.8
37.0
38.2
39.8
39.8
38.8
39.5
39.0
39.2
39.2
39.8
39.6
39.7
39.0
39.5
38.6
35.5
39.8
pH
9--0
—
7.0
-
6.8
_
7.0
-
6.8
-
7.0
-
6.8
-
6.9
-
6.9

7.0
-
6.9
6.9
6.8
7.0
Specific^
gravity
9--0
1.082
-
1.086
-
1.085
-
1.086
-
1.085
-
1.085
-
1.088
-
1.089
-
1.088
-
1.086
-
1.086
1.082
1.089

Note:
(1)
(A)
Sample
point Identl
fi cat ion
Specific gravity is reported
Not included in statistical
numbers
as shown
on flow
diagrams.
at temperature shown 1n the table
data. Appears inconsistent with al

above.
1 other m

easurement

:s.

-------
 TABLE 23.   SP65B LOW PRESSURE SEPARATOR EFFLUENT SUSPENDED SOLIDS

Sample time
Day Hour
08 15
09 15

Total
88
131
Freon
soluble
72
94
Freon
insoluble
16
38
Acid
soluble
6
20

Fi xed
10
18

             TABLE 24.  SP65B SULFATE REDUCING BACTERIA

Sample point
Flotation Unit - Out (9--0)
Flotation Unit - In (9— i)
FWKO - Out (5A30)
Oil Treater - Out (6—0)
Skim Pile (13—0)
Sump (14—0)

Sample No. 1
0
0
0
0
0
0

Sample No.
0
0
0
0
0
0

2

Sample Day and Hour:  04 at 13
                                 62

-------
	TABLE 25.  SP65B WATER CUT AT VARIOUS SAMPLE POINTS

Sample  time                     	Hater cut, %	
Day    Hour                       Skim pile out        Sump  out
01 10
02 10
03 10
04 10
05 10
06 10
07 10
08 10
09 10
10 10
Mi n i mum
Maximum
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
100
97
100
97
100

       TABLE 26.   SP65B IONIC ANALYSIS  FLOTATION  UNIT EFFLUENT

Constituent                                  Concentration,  mg/1
Sodium (Ma)                                         82,000
Calcium (Ca)                                         3,100
Magnesium (Mg)                                         910
Barium (Ba)                                            650
Chloride (Cl)                                       53,900
Sulfate (S04)                                          188
Alkalinity   (as HCO,)                                 214
Iron (Total)        J                                    4
Sulfide (as H2S)                                 .        1.3

Total Dissolved Solids
     Summation                                     141,000
     Gravimetric                                   105,000

Sample Day and Hour:  03 at 13
                                 63

-------
        TABLE 27.  SP65B FW.KO EFFLUENT SUSCEPTIBILITY TO SEPARATION
         Sampling  time
                                          Test  number
                        Mean
            Day
            Hour
            Minute
         4      8
         9      9
         30      30
         Settling  time,
             minutes

             0-1  (1)
              5
              15
              30
              60
             120
           IR-Oil. mg/1
409
331
331
270
231
.144
313
291
270
209
191
113
361
311
300
240
211
128
     (1)   The actual  settling  time  is  the  time  required  to  handle  the
          separatory  funnel  after filling  and to  draw  a  sample,  and  is
          estimated at  not  more  than one minute.

all  samples:  temperature,  pH, and  specific gravity.  These parameters were
therefore not examined for correlation with sample-to-sample variation in
effluent oil content on SP65B.  These parameters will  be discussed with
respect to variations between platforms in Section 17.

     Only one ionic analysis test and one sulfate reducing bacteria test per
sample point were run on SP65B.   These tests also are only significant with
respect to comparisons between platforms.
Crude Oil Tests

    All crude oil test results
temperature, specific gravity,
narrow ranges.
are listed in Tables 28 and 29.  The crude oil
and surface tension test results all fell in
    The viscosity and boiling range distribution tests were limited in number
to one or two and are of primary significance for comparisons between plat-
forms.  Two equilibration tests were run.

    The limited number of tests run on crude oil provide only a limited
characterization of the crude oil.
                                     64

-------
            TABLE 28.  SP65B CRUDE OIL MISCELLANEOUS TESTS
                                                           (1)

Sample time
Day Hour
01 08
02 08
03 08
04 08
05 03
06 08
07 08
08 08
09 08
10 08
Mean
Minimum
Maximum
Temperature
L_^
32.7
36.5
32.0
34.2
32.0
39.0
39.5
38.2
38.8
36.7
36.0
32.0
39.5
Specific^
gravity
0.869
0.866
0.866
0.866
0.860
0.864
0.863
0.863
8.865
0.865
0.865
0.860
0.869
Surface tension^
dynes/cm
30
30
30
30
30
31
31
30
30
28
30
28
31
Sample  time
Day    Hour
03
10
                          Viscosity at 37.77°C
 Kinematic
centistokes

   9.51
 Absolute
centipoise

   8.24
Oil/Water Ratio
IR-Oil, mg/1
                          Equilibration at 82°C
                        Brine TDS = 100,000 mg/1
                Test No.  1

                    4/1
                    50
               Test No. 2

                  4/1
                  56
(1)  Samples taken from LACT unit.
(2)  Reported for approximately the temperature in table,
                                  65

-------
        TABLE 29.   SP65B  CRUDE OIL  BOILING  RANGE  DISTRIBUTION


Initial Boiling Point, °C
Final Boiling Point, °C
Boiling range, °C
Below - 200
200 - 250
250 - 300
300 - 350
350 - 400
400 - 450
450 - 500
500 - 550
Total
Run No.
150
480

46.3
10.9
14.6
16.1
5.2
5.7
1.1
0.2
100.1
1 Run No. 2
150
480
Percent recovered
51.9
9.9
14.6
12.9
4.3
5.0
0.5
0.3
99.9
Mean
150
480

49.1
10.4
14.6
14.5
5.0
5.4
0.8
0.2
100.0
Sample Day and Hour:  03 at 10
                                  66

-------
                                  SECTION 7

                               PLATFORM WD45C
GENERAL

     A complete ten-day test program was conducted on Platform WD45C from
June 25 to July 4, 1979.  Tests were added to the program plan in the field
because additional wells, one low-pressure separator, and one gun barrel  were
put in service after the plan was developed.

     Company personnel provided the facilities, accommodations, and operation-
al information needed for a successful survey.  A Company staff engineer
assisted with the program for the first nine days.

     One complete production shutdown occurred, but it was so brief that it
did not affect the survey.

FACILITIES AND OPERATIONS

Production From Wells

     A total of 29 wells were in production for at least one day during the
survey period.  Several of the wells did not produce continuously.

     All production flowed or was gas lifted to three low-pressure gas/liquid
separators.  The average daily production calculated from well test data was
388 m3/d (2,440 bpd) of oil, 684 m3/d (4,305 bpd) of water, and 69,560 std
m3/d (2,458 Mcfd) of gas.  The combined water cut was 64 percent.

     The measured oil production for the ten-day period averaged 370 m3/d
(2,330 bpd) or 4.5 percent less than the calculated production.

     Eight percent of the oil and 1.7 percent of the water were gas lifted.

Production Process System

     The flow of oil and water through the system is shown in Figure 16.
Design and operating data on major vessels are presented in Table 30.  All
wells flowed to one of three low-pressure two-phase separators in parallel.
The liquids then flowed to two gun barrels also in parallel.  Oil recovered
from each gun barrel went to storage.  A combined water stream from the two
gun barrels flowed to the flotation unit for treatment.
                                      67

-------
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      — — — INTHMITTINT HO*
                               Figure  16.   Flow  diagram,  production  process  system,  W045C.

-------
                                       TABLE 30.  WD45C VESSEL  DATA SHEET
CTl

SAl
Low pressure
gas/liquid
Vessel description separator
Trade Name or Vessel Type Vertical
Cylinder
Design Parameters
Dimensions, n. (ft) "^
Diameter. O.D.
length. S.S.
Length
Width
Height
Surface Area. »2. (ft2)
Separation Total
Per Cell
Separation Volume. »3, (bbl)
Total
Oil Phase
Water Phase
Number of Cells
Flow Rate, at3/ day, (bpd)
Overflow Rate Per Cell. (u3/d)/«2.(bpd/ft2) M
Recycle Rate, Percent of Flow
Retention Tine. mil).
Average Operating Parameters
Temperature. °C(°F)
Pressure. kPag. (psig) 360(52)
Flow Rate. «3/d (bpd)*2)
Flow Rate. Percent of Design
Overflow Rate Per Cell. (m3/d)/m2,(bpd/ft2)
Recycle Rate, Percent of Flow
Froth Flow, Percent of Flow
(1) Tank dimension.
(2) Water flow only.
(3) Effluent flow.
(4) Overflow rate is surface area divided by flow rate.
VESSEL DESIGNATION ON FLOW DIAGRAM - FIGURE 7-1
SB1 SCI 8A SB

9
Low pressure Low pressure Gravity Gravity Flotation unit.
gas/liquid gas/liquid separator. separator, hydraulic,
separator separator gun barret gun barrel dispersed gas
Sphere Vertical Vertical Vertical Monosep
Cylinder Cylinder Cylinder Model AG6000

,


3.66(12) 3.66(12)
_
_
...
-
3.05(10)
2.29(7.5)
6.1(20) 6.1(20) 1.83(6)


10.5(113) 10.5(113) 5.1(55)
-

57(360) 64(400
13(80) 16(100
44(280) 48(300

.
-
-
-

-

9.2(58)
-
-
1
981(6170)
192(112)
400
14

40.4(105) 40.0(104) 40.0(104)
410(59) 310(45)
_
398(2501) 363(2286) 691(4347)(3)
-
38(22) 35(20)
-
-




70
135(79)
570
10

-------
     As shown in the flow diagram, one gun barrel  receives only produced
fluids.  The other gun barrel  receives produced fluids, fluids from the skim
pile, the flare scrubber, and froth recycle from the flotation unit.

     Figure 17 is a flow schematic for the water handling portion of the
system.  A nominal average water flow balance is presented in the figure.
The produced water flowed continuously to and from the gun barrels at approxi-
mately the average daily rate shown.

     Froth was returned to the "A" gun barrel from the froth chamber of the
flotation unit on level control.  The pumping rate was 327 m3/d as required.

     Fluids were returned to the "A"  gun barrel from the skim pile, at a rate
of 327 m3/d.  The pump was controlled by a timer which actuated the pump every
two hours and ten minutes.  Pumping duration was just over 2.5 minutes each
time.

     Several cubic decimeters of fluid were drained from the flare scrubber
once a week.

     A flotation aid, Nalco 3349, was added to the "A" gun barrel  effluent
at the rate of 4.5 dm3/d.

     The gun barrels are dual-purpose units.  They provide gravity separation
of water from oil to prepare the oil  for sale.  They also provide primary  sep-
aration of oil from the water to prepare the water for treatment by flotation.

     The gun barrels are vertical cylindrical tanks.  Figure 18 is a dimen-
sional sketch which also shows probable flow patterns.  The water and oil
enter through a centrally located inlet pipe which discharges near the bottom.
The water outlet is near the bottom of the tank wall.  Level control is by a
water leg.

     The volume below the inlet distributor of each gun barrel is 12.7 m3(80
bbl).  At the average water flow rate for the "A"  gun barrel of 398 m3/d
(2,501 bpd), the calculated average residence time would be 46 minutes. The
affective residence time would be less because of short-circuiting between
the inlet and outlet.  Short term flow rates would be much higher than the
average rate when water is being returned from the flotation unit or skim
pile.

     Physically, the "B" gun barrel is identical to the "A" gun barrel. The
average flow rate to the "B" gun barrel was lower.  It receives continuous
flow of produced water and none of the intermittent flows.

     There is not a standard procedure for calculating the theoretical oil/
water separation capability for units of the configuration of these gun
barrels.  The jet-like inflow and potential for short circuiting limit the
effectiveness of the gun barrels as water treating gravity separators.

     The polishing unit is a proprietary one-cell  dispersed gas flotation
unit  (Monosep AG-6000).  Figure 19 is a sketch of the unit.  The unit

                                     70

-------
FROM
L.P.    	
SEPARATOR
5C..O
                           OUN BARRELS
FROKlC »*-PJ
L.P.    	
SEPARATORS  '
   FROM
 SKIM PILE
                                       8B
                                                   8B-.0)
                             FLOTATION
      8A-I  )
                                      8A
I
                                                 (
                                                                         FLOTATION  UNIT


TOTAL FLUID m Vd
bpU
WATER
OIL
m 3/d
b pi
m Vd
b pd
5K.O
459
2890
321
2019
138
871
5C-0 13.0 9F 8A
_l 8A_0 8B_D 9—1 9-.0
612 536
385S 3372
363 7 70
2286 42 440
249
1969
398 363 761 691
2501 2286 4787 4347

                                                                      k-,
                                                                                                   TO
                                                                                                 SKIM
                                                                                                 PILE
                       Figure 17.   WD45C water handling system flow schematic.

-------
OUTLET
                               INLET
                               OIL  SURFACE
                               OIL /WATER
                               INTERFACE
                                  25.4 em OIA.
                   is^fvr^.^.~*s-^w-*n^m^
                       3.66 m 01A.
                                         t
OIL OUT
                                                              6.10
                                                    8A-4.27
                                                    88-4.57
                     S I  0 E   VIEW
       Figure 18.  WD45C  gun barrel 8A &
                         72

-------
                                   SKIMMING WEIR
       FROTH
       OUTLET
        WATER
       OUTLET
         INLET

RECYCLE  PUMP
(•»« IMPLUCNT
     EDUCTOR
SAS RECYCLE LIN
INLET  S  RECYCLE
      AREA
                            FLOTATION  CHANNEL
                                     TOP VIEW
        FROTH
        OUTLET
          INUET
        OUTLET
                        FROTH
                        SUMP
                                             3.05 m
                                                     i»»
                                                     40
                                      SIDE VIEW
                    Figure 19.  WD45C  flotation unit sketch.
                                       73

-------
operates gas blanketed.  Gas for flotation is educted hydraulically.  Froth
is removed over a single weir at the outlet end.  The recycle water flow for
gas dispersion is 400 percent of the design forward flow.

     The design flow for the unit was 981 m3/d (6,170 bpd).  The average
operating flow rate was 691 m3/d (4,347 bpd), based on effluent flow or 70
percent gf design flow.  The average froth flow was 70 m3/d (440 bpd) or 10
percent of the forward flow.

SITE SPECIFIC TEST PROGRAM

     The approved program plan could not be followed because at the time of
the survey more equipment was in operation than at the time the plan was
developed.  It was necessary to add sample points and additional tests.

     The revised flow diagram was presented in Figure 16.  The revised
schedule for major brine tests is presented in Table 31.  As for all plat-
forms, samples were taken at nominal sampling times of 0800, 1000, 1300, and
1500 hours on each of the ten days.

     Particle size distribution data were obtained on WD45C and are discussed
separately in Section 16.

OPERATIONAL DATA AND OBSERVATIONS

     Measurements, observations, and records of operating conditions are
reported in this subsection.

Flow Monitoring

     The clamp-on flow monitor was applied alternately to each of the gun
barrel effluent lines.  The monitor could not be zeroed in the recommended
manner, and the measured flow rates did not match estimates from well test
data.  After the fifth day, the flow measurements were erratic and not in a
believable range.

     During the first four days the monitor appeared to provide reasonable
flow variability measurements.  An eight hour continuous flow record for
each gun barrel is presented in Figure 20.

     The flow from the "A" gun barrel  cycled up and down, mostly in the range
from 220 to 380 m3/d.  The average measured flow for the period covered was
about 300 m3/d, compared to 380 m3/d as estimated from well test data.   Water
flow to the "A" gun barrel could be substantially over 550 m3/d when the
froth pump and skim pile pump were operating.  However, either the flow
variation was damped by the gun barrel or the monitor was not detecting the
maximum flows.

     The flow pattern for the "B" gun barrel also followed a cyclic pattern.
The average measured flow was about 330 m3/d, in the range from 245 to
410 m3/d.  The flow estimated from well test data for the same period was 380
m3/d.

                                      74

-------
L.P.
SEPARATORS



A
GRAVITY
SEPARATORS

1 V
1 1 w
1 ^

FLOTATION
UNIT

I ^-

                                      TABLE  31.   WD45C TEST SCHEDULE  FOR THE  MAJOR BRINE  TESTS
                                                                                        SAMPLE POINTS
in
9—0 9*1 8/^0

Field Tests
Infrared Oil
Temperature
pH
Water Specific Gravity
Water Surface Tension
ID-Oil W/Sillca Gel
IR-Oil Filtered Brine
Susceptibility to Separation
No. of
tests
40
20
10
10
10
20
10
Tine of
tests
8.10.13.15
8.10
10
8
8
8.13
8
No. of
tests
40
10
3
Tine of No. of Time of
tests tests tests
8.10.13.15 20 10.15
10 10 10
(1) "
V V V
8&0 8AVi 88*1
No. of Time of No. of Time of No. of Time of
tests tests tests tests tests tests
20 10.15 ....
10 10 10 8
       Laboratory Tests
         Gravimetric Oil                   40  8.10.13,15
         Suspended Solids                  10      15
         Ionic Analysis                    1      (1)
         Bacterial Culture                  1      (l)
         Particle Size Distribution         3      (I)
20
10
8.13
 15

 (i)
                           (1)
                                       (1)
(1)
        (1)  Sampling times not  shown will be field  scheduled.
                                                                                                  NOTE:  Time of tests listed is by Military hour.  Some of
                                                                                                        the one-a-day samples were not scheduled for a certain
                                                                                                        hour and are listed at the time actually run.

-------
                                       RUS   ..A« Gun Barrel -  Day  2
                                                       Hour
en
                                           "B" Gun Barrel -  Days 4 & 5
     30
    gpm
                                                       Hour
                                Figure 20.   Flow chart  WD45C gun  barrel  effluents.

-------
     Well test data are considered more accurate than the flow monitor data
for estimating average hydraulic loading of the gun barrels and flotation
unit.

Well Test Data

     Well test data provided by the operator are presented in Table 32.  The
well data are separated in groups according to which gun barrel! ultimately
received the flow.  Data for gas-lift wells are also grouped separately.  All
wells flow first to a low-pressure two-phase separator.  The table also shows
whether a well produced all the time or for only part of the survey period.

     The water balance flow rates previously presented in Figure 17 were
calculated from the well test data.

     As reported earlier, measured oil production and production calculated
from well test data were within 4.5 percent of each other.  This lends con-
fidence to the water balance estimates.

Vessel Temperature and Pressures

     The pressure of each of the three low-pressure separators was recorded
twice per day.  All other vessels were at atmospheric pressure.  The temper-
ature of the effluent from each vessel was measured once per day.

     Temperature and pressure ranges for the ten-day period are presented in
Table 33.

     The table indicates significant temperature and pressure variations
during the test period.

Pressure Drops Through System

     Table 34 presents pressure drops from the producing formations through
the system.

     The table includes only the wells producing water.  For comparison, the
table shows that the greatest pressure drops occur from the formation to the
chokes, substantial drops occur at the chokes, and more minor drops from the
chokes on.

     The pressure drop data are recorded to permit examining the theory that
pressure drops and turbulences may result in small-drop dispersions that are
difficult to remove in separation equipment.

Chemical Addition
     Five chemicals were added by metering pumps as listed in Table 35.

     The foam inhibitor was diluted with diesel and fed at concentrations of
1-3 percent.  The other chemicals listed in Table 35 were fed neat.
                                    77

-------
                                                              TABLE  32.   WD45C WELL  TEST DATA
00
Well Formation
Gun Barrel 8A Uells
Flowing to low Pressure
B-4- JCA84
B-90 GG-B5
BIO- JCMC4
Bioa IM---
Bll- JACB11
BHO I«ll
C-40 FQ-C4
C-6D JCJC4
C-BT 1M-C8
OOD IHC10
CUD HKC11
Total (Average)


Separator
7.862
6,068
7.416
7.271
8.896
8. 511
5.505
7.416
B ,734
8.743
7.2)9
(7.604)
Gas
TC73"


66
62
85
65
172
84
42
17
44
28
32
697
Oil
15pa


IB
316
39
0
98
50
31
36
3
9
58
660
Water
bpd


0
5
351
285
183
22
46
0
124
866
232
2,114
Lift gas
Hcfd


0
0
0
0
0
0
0
0
0
0
0

Pressure,
SIBHP


3,793
2.550
3,800
4,350
4.105
4.095
2.415
2.987
4.860
4.912
3.449
(3.756)
PS IQ
FTP


350
300
600
750
725
180
225
325
1.150
850
420
(534)
Choke size
1/64 ?n.


6.0
14.5
11.0
10.0
11.0
14.0
10.0
6.0
6.0
13.0
12.0
(10.3)
API gravity


27.4
28.6
24.4
1
26.1
29.2 1
21.9
29.5
29.2
30.6
26.8
(27-4)
Days of
production


All
All
All
,4.5(AM)6.7.8,9.10
All
,2.3.4.5(AM)6.7(AH)
All
All
1.2,3
All
All

Gas lift to low Pressure Separator
B-9- JAAB9
C-7T FSUCI
Total (Average)
BA Total (Avg)
7,634
5.619
(6.626)
(7.453)
458
149
607
1.304
192
0
200
860
29
45
74
2.188
400
.
1169
1169
2.390
2,454
(2.422)
(3.651)
350
280
(315)
(500)
23.0
17.0
(20.0)
01.8)
28.6
25.2
(26.9)
(27.3)
All
All


            Gun Barrel  8B  Welts
            Flexing to  Low Pressure Separator
H-l- FSIC7
H-IO FQ-C1
H-2- JABC5
H-20 GG-C1
H-3A ' IF-C2
H-3& GG-E1
H-4D JABC4
H-5D GG-C1
11-6- JAAC5
H-6D GG-B5
tl-70 JAAC8
H-9- JABCS
H-90 1MC10
H»20 FSLC7
HMD FSUCI
88 Total (Average)
8A 1 8B Total (Avg)
Temporary
C-6- JCNC4
5,603
5.469
8.836
6,297
7.329
6.206
7.269
6,229
8.151
6.236
8.875
8.408
8.100
5.608
5.547
(6.944)
(7,180)

7,492
                                                 64
                                                 54
                                                 17
                                                 11
                                                 32
                                                211
                                                125
                                                 18
                                                169
                                                156
                                                 40
                                                108
                                                 28
                                                )57
                                                 32
                                               1.222
  253
  205
   53
   51
  160
   68
  302
  110
   68
   71
   50
   52
   46
   79
   78
1.646
                                               2.526    2.506
  170
  138
   99
  152
  149
  274
  164
    9
  160
  214
  282
  157
   86
  320
   42
2.416

4.604
                                                306
                                                         269
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
                     1169


                        0
  .413
  .378
  .223
  .915
  .219
  .840
  .725
 3.420
 3.924
 2.834
 3.978
 3.242
 2,953
 2.465
 2.470
(3.000)

(3.256)
                                                                                         2.767
 300
 325
 300
 160
 160
 400
 260
 515
 830
 225
 700
 250
 280
 225
 360
(353)

(421)
                                                675
 17.0
 14.5
 10.0
 IS.O
 17.0
 17.0
 22.0
  7.0
  7.0
 18.0
 10.0
 14.0
 11.0
 24.0
  9.0
(13.3)

(11.3)
                                                14.0
 24.2
 20.2
 18.8
 18.8
 24.6
 20.6
 27.5
 28.9
 29.6
 20.5
'26.8
 29.9
 29.9
 24.1
 25.1
(24.6)

(25.8)
                                                                           21.2
      All
      Alt
      All
      All
      All
      All
      All
4(PM)5.6.7.8
      All
      All
     .3.4.5
      All
      All
      Alt
      All
1.2.

-------
             TABLE 33.   WD45C VESSEL TEMPERATURES AND PRESSURES
Vessel
                Pressure,
                  kPag
                 (psig)
                       Temperature,
                            °C
Low Pressure
Separator 5A1

Low Pressure
Separator 5A2

Low Pressure
Separator 5A3

Gun Barrel 8A
Gun Barrel 8B
Flotation Unit 9
                276-552
                (40-80)

                386-600
                (56-87)

                262-490
                (38-71)

                   0
                  (0)

                   0
                  (0)

                   0
                  (0)
                        38.0-41.8


                        39.0-40.6


                        36.8-46.0
Location
               TABLE 34.  WD45C PRESSURE DROPS THROUGH SYSTEM
Pressure,
  kPag
 (psig)
    Pressure drop,
point or description
Pressure drop,
    kPag
   (psig)
Formation
(SIBHP)
Flowing Tubing
Pressure
Low Pressure
Separators
Skim Tank
16,400-33,870
(2,378-4,912)
 1,105-7,930
  (160-1,150)
   260-600
   (38-87)
    perforations,
    static head,
    pipes
    chokes,
    valves,
    pipes
    control  valve,
    pipes
14,065-28,010
(2,040-4,062)
   795-7,520
  (115,-1,091)
   260-600
   (38-87)
                                     79

-------
                                                  TABLE  35.   WD45C CHEMICAL ADDITION
CD
O
Chemical
Nalco 970. "Gas-Cor"
(Gas system corrosion
inhibitor)
Nalco 9)4. "Visco"
(Paraffin control)




T reunite RP 79
(Demulsifier)


Dow 200
(Foam inhibitor)


Nalco 3349, "(Coagulant"
(Water treatment)
Flow diagram
identifier
2K


19K





7B
•
7C

20K

20C

10

Addition
point
Lift gas line to all
gas lift wells

Lift gas line to all
gas lift wells




Well Manifold ahead
of 5B1
Well manifold ahead
of SCI
Between wells and
5A1 and 5B1
Well manifold
ahead of SCI
Effluent from 8A
gun barrel
Addition rate
Gun barrel dm3/d pprnv
1.9


3.4





8A 8.3 16^*
%
8B 6.4 Ifl'1'

8A 0.8 iV1*

8B 1.1 1.9(1*

4.5 7<2>

Operation
Continuous after
Day \ at 1330

Malfunctions on Day
1 until 1330. even-
ing Day 3 until Day
5 at 1430 and morn-
ing Day 6 until
afternoon Day 7
Continuous

Continuous

Continuous

Continuous

Malfunction on part
of Day 4 and 5

                    !1)  Based on average  fluid flow into the gun barrel.
                    2)
Based on average flow of water discharged from the flotation unit.

-------
     Chemical usage was monitored by measuring the chemical level in the feed
pump reservoirs twice a day.  Interruptions in feed pump operation are shown
in Table 35.  The pump for water treatment chemical, Nalco 3349, stopped
pumping liquid some time during Day 4 and was not repaired until about 1330
on Day 5.  On Day 4, from 0630 to 1815, the pump added chemical at a rate of
1.5 dm3/d (0.4 gpd).  This is less than half the average operating rate of
4.5 dm3/d (1.2 gpd) shown in Table 35.

     The gun barrels are treated with biocide once per month.   The gun barrels
were treated on June 22, 1979, three days before the Program started.  Thirty
sticks of Tretolite Fludex, WF 75S, were added to each gun barrel.  Fludex is
a multi-purpose water-treatment additive.  The treatment alternates monthly
from Fludex one month to Tretolite X-CIDE 370 the next month.

     About one cubic meter of packing fluid from well  BUD flowed to the 8A
gun barrel on Day 8.  This incident is discussed in the following subsection.
During this incident, additional chemicals were added  to moderate the adverse
effect of this packing fluid on the pipeline oil BS&W  content and the flota-
tion unit effluent oil content.  The chemicals were added both continuously
and on a batch basis.  Tretolite F17 was added continuously at two places
between the well and low-pressure separator 5A1.  One  pump added 1.1 dm3
between 1200 and 1645.  The other pump added 1.5 dm3 from 1230 to 1530.  The
batch treatment was accomplished by dumping the chemical in the flotation
unit froth sump which then pumped it to the 8A gun barrel.  The batch treat-
ments are listed in Table 36.

	TABLE 36.  WD45C CHEMICAL BATCH TREATMENTS	

                                                            Quantity,
Chemical                               Time                 dm3 (gal)


Tretolite F17                          1250                 11.4 (3)
Nalco 3349                             1335                  3.8 (1)
Tretolite F17                       1330-1400               11.4 (3)
Observations and Operator Reports

     An effort was made to record any event that could affect effluent water
oil content.  The operators were requested to provide information on upsets
and intermittent operational or maintenance procedures, and the survey team
made their own observations.  Well  production interruptions longer than
half a day are shown in Table 32, Well Test Data.  The interruptions and
changes that could have an effect on the treating system are discussed in the
following sentences.

     Several well changes could have had an effect on the treating system on
Day 4.  Well B10D which flows to low-pressure separator 5A1 began producing
at 1630 on Day 3.  This well produces 45 m3/d (285 bpd) of fluid according to


                                     81

-------
well test data.  Well C6 "loaded up" and "died" the night of Day 3.  In order
to "unload" the well, it was changed from the high-pressure system to low-
pressure separator 5B1.  This well  produced 43 nr/d (269 bpd) of fluid accord-
ing to well test data.  These two wells added 88 m3/d (554 bpd) of flow to gun
barrel 8A.  This is a 16 percent increase in flow over the average 536 m3/d
(3,372 bpd).  Well C6 returned to the high-pressure system at 0800 on Day 5.

     The morning of Day 4 at 0730 the flotation unit influent was unusually
high in oil content.  Table 37 lists the visual observations that followed.

	TABLE 37.  WD45C DAY 4 8A GUN BARREL OBSERVATIONS	

                     	8A gun barrel	
Time                 Influent                          Effluent


0730                    -                 Lots of sand.
1030                 No sand.             Sand and fluctuating quality.
1100                    -                 2% oil and 1% solids.
1200                    -                 Much cleaner.
1600                    -                 No free oil or solids.
     All wells were shut in part of the afternoon of Day 4.  Table 38 lists
the times for this shut in.


	TABLE 38.  WD45C DAY 4 PLATFORM SHUT IN	

Platform                           Shut in                   Open
B
C
H
1200
1330
1330
1445
1430
1500

     The low-pressure separator maximum pressures occurred at 1600 on Day 4.
Well BUD was shut in at 1200 on Day 7.  The purpose of the shut in was to
change the well from a flowing well to a gas lift well.  To accomplish this
change, the calcium bromide packing fluid had to be displaced.  The oily
packing fluid was processed through the treatment system.  The discharge of
packing fluid from the well began about 1130 on Day 8 and was completed
about 1600.

     Three deck washings were performed to clean up spilled oil.  The soap
was DW-9 Rig Wash from M-Chem.  Table 39 lists the incidents and times.
                                      82

-------
                       TABLE 39.  W045C DECK WASHING
                                                         Subsequent
Day                           Washdown period          skim pile pumping
05
06
07
0730-0900
1500
0630-1000
1100
1500
1000

     It rained on Day 6 from 1500 to 1600.  The flow was to the skim pile,
and the flow through the treating system was not increased.

     The flotation unit froth flow was calculated twice per day from the
froth sump fill time.  The flow averaged 70 m3/d (440 bpd).  The minimum flow
was 5 m3/d (31 bpd) which occurred on the afternoon on Day 5, both times on
Day 6, and in the morning on Day 9.  The maximum flow rate was 177 m3/d
(1,110 bpd) at 1200 on Day 7.

DATA PRESENTATION AND EVALUATION

     Comprehensive data tables, summary tables, and graphs are interspersed
in the text.

Effluent Oil Content

     Table 40 presents a listing of all oil content tests.  The ranges of
test results are as follows:           ,

     Flotation Effluent GR-Oil  - 17 to 465 mg/1,
     Flotation Effluent IR-Oil  - 31 to 516 mg/1,
     Flotation Influent GR-Oil  - 76 to 12,512 mg/1,
     Flotation Influent IR-Oil  - 98 to 15,577 mg/1.

     Figure 21 is a plot of GR-Oil  content in and out of the flotation unit
versus time.  Figure 22 is a similar plot for IR-Oil content.  The graphs
exhibit three effluent oil content peaks that are substantially above the
typical range during the ten-day test period.  The effluent peaks correspond
with influent peaks.

     The oil content peak on Day 4 corresponded with an above average flow to
the "A" gun barrel as described in the subsection on field observations.

     The feed pump for the water treating chemical  was off from the middle of
Day 4 to about 1330 hours on Day 5.  Any effect on effluent oil content
should have been apparent on the first two samples on Day 5.  There was no
apparent effect since the tests on both samples were in the typical range.

     The cause of the oil content peak on Day 5 was not determined.  As dis-
cussed earlier, some washdown water containing detergent could have been

                                     83

-------
                                                    TABLE 40.   W045C  MAJOR  BRINE TESTS
'00

Gun barrel
TSX-o)
Sanple tine IR-Oil
Day Hour my/1
01 08
01 10
01 13
01 IS
02 08
02 10
02 13
02 15
03 08
03 10
03 13
03 IS
04 08
04 10
04 13,
04 15
OS 08
OS 10
05 13<
OS IS
06 08
06 10
06 13
06 IS
07 08
07 10
07 13
07 IS
08 08
08 10
08 13
08 IS
09 08
09 10
09 13
09 IS
10 08
10 10
10 13
10 IS
Hininun
Maximum
.
187
-
543
.
142
.
271
.
138
.
129
.
5.741

) 401
__
120
)
263
.
338
-
182
.
169
_
360
.
249
-
303
.
231
.
151
_
218
.
187
120
5.741
effluents
(8B-0)
IR-Oil
•9/1
.
66
-
78
-
53
.
54
-
69
-
68
-
93
.
196
.
50
.
62
.
125
.
214
.
182
.
116
.
134
-
98
.
107
-
63
.
44
-
48
44
214
Flotation
influent
GR-Oil
ug/l
467
-
99
-
328
.
190
-
202
-
77
-
8.769
-
260
.
128
_
12.512

93
-
130
.
115
,
631
.
216
-
76
-
336
_
254
.
282
-
96
-
76
12,512
unit
(9-i)
wg/1
445
498
125
151
392
125
196
116
285
125
98
102
6.231
IS. 577
334
463
107
129
14.909
178
107
303
178
169
125
178
592
356
285
205
1.068
303
338
476
378
289
249
249
107
209
98
15.577

GR-011
iig/1
27
17
22
35
22
26
28
31
43
21
25
22
371
289
58
35
40
31
465
56
26
39
27
26
29
32
78
48
44
31
29
152
37
42
34
46
39
26
31
26
17
465

1M11
mg/1
43
31
36
45
35
36
43
47
63
32
42
34
445
343
63
52
50
35
516
72
36
44
36
36
37
38
41
65
59
42
214
165
48
57
46
55
44
40
38
37
31
516
Flotation
IR-011 w/silica
dispersed So
ng/l
27
-
20
-
20
.
25
.
34
.
22
-
338
-
43
.
32
.
392
.
21
.
18
-
20
.
23
.
37
-
146
-
32
.
27
_
28
_
23
-
18
392
unit
qel
luble
16
-
16
-
15
.
18
-
19
-
20
-
107
-
20
.
18
.
124
.
IS
-
18
.
17
.
18
-
22
-
68
-
16
.
19
-
16
.
15
-
IS
124
effluent (9--0)
Filtered
brine
IR-Oit
ng/1
28
-
-
-
28
_
.
_
34
.
.
.
271
-
.
-
32
_
.
.
27
.
-
.
25
.
.
-
27
.
-
.
32
.
.
.
21
.
.
-
21
271

Surface
tension
dynes/cm
60
-
-
-
59
.
.
.
66
.
.
.
44
-
.
-
62
.
.
-
65
.
-
_
56
.
-
.
61
-
-
-
60
.
.
.
63
-
.
-
44
66

Flow
Out(2)
•3/d
737
737
737
737
692
692
692
£92
692
£92
£92
692
718
718
718
718
694
£94
£94
694
£74
674
£74
674
£72
672
672
672
671
£71
671
£71
669
669
£69
669
-
-
.
-
669
737

rate
JUmraings
28
28
28
28
148
148
74
74
161
161
59
59
65
65
90
90
39
39
39
S
10
5
50
5
177
177
84
84
82
82
32
32
S
S
136
136
32
32
113
113
5
177
               1)
Flotation chemical was not being added because the pump was not functioning properly.
Based on well test data.

-------
oo
tn
              aoo-
              7OO-
             600-
              5OO-
       QR-OIL
mg/l
              4OO-
              300-
              2OO-
              100-
                                                                          EFFLUENT
                                                             DAY
                                                                       "»    r    '    a
                                                                                               10
                          Figure 21.  WD45C flotation  unit performance, GR-oi! vs time.

-------
       800-
       7OO—
        6QO-
        5OO
IR-OIL
 mg/l
         o
                                                                                                IO
                   Figure 22.  WD45C  flotation  unit  performance,  IR-oil  vs time.

-------
pumped to the "A" gun barrel at 1100 hours.  However, the amount would have
been small and should have been flushed through the system by the 1300 hour
sampling time.

     The third effluent oil content peak occurred on Day 8.  It corresponded
with about one cubic meter of calcium bromide packing fluid flowing from
Well BUD to the "A" gun barrel.

     Flotation unit effluent oil content histograms are presented in Figure
23 and Figure 24.  Figure 25 is a regression plot of effluent GR-Oil versus
IR-Oil.  A summary comparison of effluent oil content by the two methods is
presented in Table 41.

     The histograms indicate a similar frequency distribution for the two
test methods.  The regression plot and correlation coefficient indicate a sig-
nificant correlation for the two test methods.  However, the standard devia-
tion for differences in paired tests of 30 mg/1 is quite high.

     As shown in Table 41, the IR-Oil mean is 81 mg/1, or 18 mg/1 higher than
the GR-Oil mean.  Only one gravimetric test result exceeds the paired IR-Oil
test result.  The samples for the tests by the two methods were taken about
one minute apart from a flowing stream.  Differences in paired tests include
sampling and testing variability.

     The four GR-Oil values and five IR-Oil values over 100 mg/1 have a strong
influence on the mean oil content by both test methods, and also a strong in-
fluence in establishing the standard deviations.

     All test results for dispersed oil and soluble oil as measured by the
IR-Oil w/Silica Gel test are listed in Table 40.  A summary of these test
results is presented in Table 42.

     On average, 31 percent of the oil in the effluent was soluble oil and
69 percent was dispersed oil.

     Linear regression plots of dispersed oil versus IR-Oil and GR-Oil are
presented in Figure 26.  Extrapolation of the linear regression lines to
zero dispersed oil indicates a residual IR-Oil of 10 mg/1 and a residual
GR-Oil of 1 mg/1 would still be present in the brine after all dispersed
oil is removed.  The lowest soluble oil test result during the survey was
15 mg/1 out of a total of 20 tests.  In this case, extrapolation of the
linear regression lines to zero dispersed oil may indicate a lower dispersed
oil content than can actually be obtained.

Surface Tension

     All surface tension test results are reported in Table 40.  The mean
surface tension of the flotation effluent is 60 dynes/cm.

     Nine of the ten flotation effluent surface tension test results were
in the range of 56 to 66 dynes/cm.  The other result was 44 dynes/cm.  The
linear regression equation for effluent IR-Oil and surface tension is:

                                     87

-------
30-
—

"•
>?20-
>" —
o
ZM
UJ
3
0
UJ —
£ io-
0-
i











r
i
«














i i i i i i i r i i i i i i f i i i i i i i i t _
n s 40
I* 63
» * 95
-
2 OF 40 VALUES IN MEAN OVER 300 m
-------
00
VO
               2OO-
               150-
       GR-OIL
lOO-i
                50-
                             i—i—n—i—i—i—i—i—i—i—\—T~T—I—i—\   i   i   i   i   i   r~ii   i   r
                          GR-OIL=-4.8 + 0.84( IR-OIL)

                               r=096


                         7.5% OF DATA INCLUDED IN EQUATION  OFF  GRAPH
                              .; . »
                              *•/
                          i   i  i   i  r  i   i   i   r  i   rii   it   i   i   i   i   i   i   i   i   i  i   i   i    r
                                  50             100            ISO             ZOO            25O

                                                            IR-OIL,mg/l

                      Figure 25.   WD45C flotation unit effluent,  infrared-gravimetric  regression.
-------
                  TABLE 41.   WD45C FLOTATION UNIT EFFLUENT
                         GR-OIL AND IR-OIL COMPARISON
— _ 	
011 content

Number of tests, (n)
Mean, (x), mg/1
Minimum, mg/1
Maximum, mg/1
Standard Deviation, (s), mg/1

GR-Oil
40
63
17
465
95
Paired
IR-Oil
40
81
31
516
109
Tests
Number, (n)
Mean of Differences, (A), mg/1
Standard Deviation,(s.), mg/1
40
20
30
                    TABLE 42.  W045C SOLUBLE OIL  SUMMARY

Analysis or test
IR-Oil
Dispersed Oil
Soluble Oil
Flotation effluent
Range Mean
mg/1 mg/1
35-516 96
18-392 66
15-124 30
Proportion
of total ,
percent
100
69
31

 Note:   Table  includes  only  IR-Oil  tests  when  an  IR-Oil  w/Silica  Gel  test was
        run.
              IR-Oil  = 1,147 -  17.8  (Surface  Tension)
                   r  = 0.87

      The calculated  regression equation  indicates  a  rapid decrease in IR-Oil
 as  surface tension increases.

 Suspended Solids

      Suspended solids test  data are presented in  Table 43 for major sampling
 points.   A suspended solids summary for  WD45C is  presented in Table 44.
                                      90
-------
        140-
        120-
        100-J
TOTAL
  OIL
 mg/l
         30-
         60-
         4O—
         20-
1   I  r   1  Tl   r  1   1  I   I  'i  I   I  I  I   i  I   1  I
     •  TOTAL IR-OILVS  DISPERSED  IR-OlL
     TOTAL IR-OIL * 10+ 1.3  ( DISPERSED IR-OIL)
     r •• 1.0

     •  TOTAL GR-OIL VS DISPERSED  IR-OIL
     TOTAL  GR-OIL»2.0+ I.I  (  DISPERSED  IR-OIL)
     r * 0.96
      15 %  OF DATA INCLUDED IN  EQUATIONS OFF GRAPH
                                                                       1  i   r
               i
              0
                    TOTAL  IR-OIL-  DISP€I»eD  IR-OIL
                                      TOTAL SR-OIL-  DISP€RSED.  IR-OIL-
     i   r i   i   i  i   (  i  j  i   i  i   I  i  i   i  I
                   DISPERSED   IR-OIL,  mq/
              Figure  26.   WD45C flotation  unit effluent,
                total  oil  - dispersed oil  regression.
                                    91
-------
                                      TABLE 43.  WD45C SUSPENDED SOLIDS TESTS
10
IM
Gravity
Frebn
Sample time Total soluble
Day Hour mg/I ng/l
01 IS
02 IS
03 18
04 IS
05 15
06 IS
07 IS
08 IS
09 IS
10 IS
Minimum
Maximum
separator, in (8--I)
Freon Acid
lUSOJyttk ifilyblg fixed Total
W/r"* -igTT SgTT igTT
102
100
133
83
96
135
233
- 211
144
73
73
233
flotation unit, in
Freon
86
74
114
69
76
55
54
160
106
49
49
160
Freon
Insoluble
ng/i
16
25
19
14
20
80
179
51
38
24
14
179
(9--1)
Flotation unit, out (9—0)
Acid
.ifllutlfi Fixed
9
4
11
7
a
14
16
28
10
7
4
28
7
21
a
7
12
66
163
23
28
17
7
163
Total
IgTT
38
43
68
60
72
213
117
116
56
136
38
213
Freon
soluble
rng/1 '
20
22
45
34
45
148
21
89
31
110
20
I4B
Freon
insoluble
18
21
23
26
26
65
96
27
26
26
18
96
Acid
soluble
IWj/ 1
16
17
18
23
21
42
28
21
13
21
13
42
Fixed
2
4
4
4
5
23
68
6
13
5
2
68
-------
                  TABLE 44.   WD45C SUSPENDED SOLIDS SUMMARY
Suspended Solids
Average suspended solids, mg/1
    9—i              9—0
Total
Freon Soluble
Freon Insoluble
Acid Soluble
Fixed
131
84
47
11
35
92
57
35
22
13

     More than half of the solids are Freon soluble.  Except for acid soluble
solids, the other solids decrease across the flotation unit.

     Figure 27 presents time-indexed plots of Freon insoluble suspended sol-
ids in the flotation influent and effluent, and of flotation effluent dis-
persed oil.  The suspended solids samples were taken at 1500 each day and
the dispersed oil samples were taken at 0800 and 1300 each day.

     The plotted data do not demonstrate a distinct pattern that the dis-
persed oil content of the effluent is higher when flotation influent or
effluent suspended solids are higher.  The lack of a readily apparent
relationship may be because the samples were not all taken at the same time
and also because of the substantial  variability of the suspended solids test.

Filtered Brine

     The filtered brine IR-Oil  content of WD45C effluent was in the range
of 21 to 271 mg/1 with a mean of 53 mg/1.  The mean IR-Oil content of un-
filtered brine on WD45C was 85  mg/1  for samples when filtered brine tests
were also run.  The oil content of the filtered brine is lower than that of
the unfiltered brine as expected.  However, as discussed in Section 5, there
is a bias of an unknown amount  with certain brines which limits the confi-
dence that can be placed in the test.

Flotation Unit Performance

     Figure 28 is a regression  plot of IR-Oil  in and out of the flotation
unit.  Flotation effluent IR-Oil  content increases gradually as influent
IR-Oil  content increases.   The  slope of the regression line is only 0.028.

     Thirty-six of forty flotation influent IR-Oil  test results are in the
range from 98 to 592 mg/1.  The other four test results are from 1,068
to 15,577 mg/1.  High effluent  oil contents occurred at the same time as
the four high influent oil contents.   This is  illustrated in Table 45.
                                     93
-------
10
             ISO
          t>

          •h


         o
         u
         o

         o
         o
             100
              60
 EFFLUENT
DISPERSED
   OIL
                                                                      EFFLUENT

                                                                      DISPERSED

                                                                         OIL
                                                                                             """ "T^^— ——3>^>*>:
                                                                                                         10
                                                             DAY
                          Figure 27.   WD45C flotation unit Freon  insoluble suspended solids.
-------
01
          20CH
       5  180H

       IK
       h-

       Z
       Ui
ft  IO  ir




                   IR - OIL out - 48+0.028 (IR-OIL In)



                   J0% OF DATA INCLUDED INEQUATION  OFF GRAPH
                                                                                                  I  I   I  I
                                                         I  I  I  I   I  I   I- I  M  I  I  1   I  I  I  I  I
                                                                 900          600          TOO
                     I  I  II  I  I 111  I  I   II   I  I  »»  I
                         100         260         300         400         900

                                      FLOTATION UNIT  INFLUENT IR-OIL, mfl/l



                           Figure 28.   WD45C  flotation  unit in-out IR-oil regression.
-------
                   TABLE 45.  WD45C IR-OIL CONTENT SUMMARY
Sample time
Day    Hour
                                      Flotation unit IR-Oil , mg/1
                                      Influent
                  Effluent
Four High Test Results
04
04
05
08
08
10
13
13
Mean
Other Thirty-Six Test Results
 6,231
15,557
14,909
 1,068

 9,441
445
343
516
214

380
Mean
Minimum
Maximum
249
98
592
48
31 ,.
65,(63,72,165)U

(1)  The samples for the three values in ( ) were taken 2 hours after one of
     the four high values.  The flotation unit operation may not have had
     time to stabilize.

     When all flotation unit influent and effluent oil  content test results
are considered, both the exceptionally high and the low, there is a clear
indication that a consistent flotation influent would result in a more con-
sistent effluent.

Gun Barrel Performance

     Twenty IR-Oil tests were run on the effluent of each gun barrel.  Forty
IR-Oil and forty GR-Oil tests were run on the combined effluent of the two
gun barrels which is also the flotation unit influent.   All  test results are
listed in Table 40.

     The "B" gun barrel IR-Oil content averaged 96 mg/1.  Over one-half of
the values were less than 100 mg/1, and only one exceeded 200 mg/1.  This gun
barrel did not receive flotation froth recycle or any intermittent flows,
aside from variations in well flow rates.

     The average effluent IR-Oil of the "A" gun barrel  was 516 mg/1.  The "A"
gun barrel received froth recycle and other intermittent flows as described
earlier.

     The IR-Oil content for the combined stream from the two gun barrels
averaged 1,169 mg/1.  The IR-Oil content of four samples was over 1,000 mg/1.
The GR-Oil content of the combined stream averaged 1,263 mg/1..  The lines
labeled "influent" in Figure 21 and Figure 22 illustrate the variability in
oil content of the combined stream from the gun barrels.
                                      96
-------
     The results of three susceptibility to separation tests on the combined
flow from the two gun barrels are presented in Table 46.  The tests indicate
oil is readily separated from the brine on WD45C.  After five minutes of
static settling under test conditions, the mean IR-Oil content of the brine
was 59 mg/1.  This is a lower oil content than was accomplished by the gun
barrels.  A graphical settling rate comparison with samples from other plat-
forms is presented in Section 17.
               TABLE 46.   WD45C COMBINED GUN BARRELS EFFLUENT
              	SUSCEPTIBILITY TO SEPARATION	

                                              Test number
69
55
56
54
49
49
88
68
61
58
85
53
89
55
53
62
71
61
82
59
57
58
68
54
          Sampling time                 123Mean
            Day                         357
            Hour                       10     10     10
            Minute                     51     40     36
          Settling time,
            minutes                   	IR-Qil,  mg/1

            0-1 (1)
              5
             15
             30
             60
            120
    (1)   The actual  settling time is  the time required to  handle the
         separatory  funnel  after filling and to  draw a sample,  and is
         estimated at not more than one minute.

Miscellaneous Brine  Tests

     All other brine test results for WD45C are listed in Tables 47, 48, 49,
and 50.   The results for the following tests were in narrow ranges for all
samples:  temperature, pH, and specific gravity.  These parameters were
therefore not examined for correlation with sample-to-sample variation in
effluent oil content on WD45C.  These parameters will be discussed with re-
spect to variations  between platforms in Section 17.

     Only one ionic  analysis test and one sulfate reducing bacteria test per
sample point were run on WD45C.  These tests also are only significant with
respect  to comparisons between platforms.
                                     97
-------
                                   TABLE 47.  WD45C SUPPLEMENTARY BRINE TESTS
CD

Sample time
Day
01
01
02
02
03
03
04
04
05
05
06
06
07
07
08
08
09
09
10
10
Mean
Hour
08
10
08
10
08
10
08
10
08
10
08
10
08
10
08
10
08
10
08
10

Minimum
Maximum
13--0

39.0
-
39.5
-
40.0
-
39.5
-
39.7
-
38.0
-
38.6
-
40.1
-
41.2
-
40.5
40.0
38.0
41.2
8A-1
_
45.0
-
46.0
-
40.4
-
40.5
-
42.2
-
34.0
_
37.2
-
40.4
-
51.5
-
46.4
42.4
34.0
51.5
Temperature,
8A-0
.
39.7
-
40.7
-
40.6
-
40.1
-
40.5
-
38.0
-
40.0
-
41.3
-
41.8
-
41.3
40.4
38.0
41.8
8B-0

39.2
-
39.0
-
40.0
-
39.6
-
39.7
-
39.0
_
39.2
-
40.0
-
40.6
-
39.7
39.6
39.0
40.6
°C
9-1
_
39.4
.
41.0
-
40.6
-
39.5
-
40.2
-
37.7
-
39.9
-
41.0
-
41.5
-
41.2
40.2
37.7
41.5

9--0
38.2
39.4
38.7
40.2
39.4
40.6
37.5
46.0
39.0
40.4
36.8
38.2
38.2
39.7
39.0
40.7
40.2
41.7
38.7
40.7
39.7
36.8
46.0
pH
9--0

7.0
-
7.0
-
7.0
-
7.0
-
7.0
-
7.0
-
7.0
-
7.0
-
6.9
-
7.0
7.0
6.9
7.0
Specific*1*
qravity
9—0
1.070
_
1.070
-
1.075
-
1.071
-
1.075
_
1.072
-
1.072
-
1.075
-
1.073
-
1.072
-
1.073
1.070
1.075

            Note:  Sample point identification numbers  as  shown on flow diagrams.
            (1)    Specific gravity is reported at temperature shown  in the  table  above.
-------
            TABLE 48.   WD45C SULFATE  REDUCING BACTERIA
Sample point
                                     Bacteria per mill niter
Sample No.  1
Sample No.  2
Flotation Unit - Out (9—0)
Flotation Unit - In (9—1)
LP Separator "A" '- Out (5A10)
Skim Pile -- Out (13—0)
Sample Day and Hour: 06 at 19
10-100
1-10
0
1-10

10-100
10-100
0
0


         TABLE 49.   WD45C WATER CUT AT  VARIOUS SAMPLE POINTS


Sample time
Day Hour
01 10
02 10
03 10
04 10
05 10
06 10
07 10
08 10
09 10
10 10
Mean
Minimum
Maximum

Gun barrel "A"
in
73
81
74
84
76
84
91
80
83
60
79
60
91
Water cut, %
Skim oile
out
—
-
-
100
-
-
-
-
-
-
_
-
-

Flare
scrubber
„
-
-
-
-
1
-
-
1
-
_
-
-
                                99
-------
           TABLE  50.  WD45C  IONIC ANALYSIS  FLOTATION  UNIT  EFFLUENT

    Constituent                                   Concentration, mg/1
Sodium (Na)
Calcium (Ca)
Magnesium (Mg)
Barium (Ba)
Chloride (Cl)
Sulfate (S04)
Alkalinity (as HC03)
Iron (Total)
Sulfide (as H2$)
75,000
6,100
1,020
1,100
37,340
170
342
7
0.68
    Total  Dissolved  Solids
         Summation                                      121,000
         Gravimetric                                    80,500

    Sample Day  and Hour:  07  at  08
Crude Oil  Tests

     All crude oil test results are listed in Tables 51 and 52.  The crude
oil temperature, specific gravity, and surface tension test results all  fell
in narrow ranges.

     The viscosity and boiling range distribution tests were limited in
number to one or two and are of primary significance for comparisons between
platforms.  Two equilibration tests were run.

     The limited number of tests run on crude oil provided only a limited
characterization of the crude oil.  Between-platform comparisons will be
presented in Section 17.
                                     100
-------
            TABLE 51.  WD45C CRUDE OIL MISCELLANEOUS TESTS

Sample time
Day Hour
01 08
02 08
03 08
04 08
05 08
06 08
07 08
08 08
09 08
10 08
Mean
Minimum
Maximum
Temperature
UC
36.0
34.2
38.5
36.2
37.5
35.7
37.6
37.2
38.8
37.0
36.9
34.2
38.8
Specific^
gravity
0.888
0.892
0.895
0.903
0.888
0.886
0.884
0.886
0.889
0.889
0.890
0.884
0.903
(2}
Surface tension
dynes /cm
29
29
31
31
31
29
29
31
31
31
30
29
31
Sample time
Day    Hour
02
08
                   Viscosity at 37.77°C
                 Kinematic        Absolute
                centistokes       centipoise
22.66
20.21
Oil/Water Ratio
IR-Oil, mg/1
                          Equilibration at 82°C
                        Brine TDS = 100,000 mg/1

                        Test No. 1    Test No. 2
                     4/1
                     137
                4/1
                125
(1)  Samples taken from LACT unit.
(2)  Reported for approximately the temperature in table,
                                101
-------
         TABLE 52.   WD45C CRUDE OIL BOILING RANGE DISTRIBUTION
Initial Boiling Point, °C
Final Boiling Point, °C
Run No. 1

   150
   490
Run No. 2

   150
   480
 Mean

 150
 485
Boiling range, °C

Below - 200
  200 - 250
  250 - 300
  300 - 350
  350 - 400
  400 - 450
  450 - 500
  500 - 550

Total

Sample Day and Hour:  02 at 08
        Percent recovered
31.7
12.0
21.8
20.2
5.8
7.4
0.8
0.4
27 .7
12.8
22.0
22.1
6.7
6.2
2.1
0.3
29.7
12.4
21.9
21.2
6.2
6.8
1.4
0.4
  100.1
   99.9
100.0
                                  102
-------
                                  SECTION 8

                                PLATFORM  ST177
GENERAL
     A nine-day test program was conducted on Platform ST177 from July 13
through July 21, 1979.  The test program was sandwiched in between two
hurricanes.

     The survey team members arrived at the platform on July 9 and set up the
test equipment the next morning.  Before noon on July 10, evacuation of the
platform was ordered because of the approach of Hurricane Bob.  The team
members repacked the equipment and left the platform that afternoon.

     The survey team returned to the platform on July 11 and set up the
equipment on July 12.  The wells which had been shut in during the hurricane
were brought back in production on July 12.  The test program started on
July 13.

     As an aftermath of Hurricane Bob, the production operations were upset
the first six days of the test program.  This is reflected in the test
results.  The last three days' operations were relatively stable.

     The test program was curtailed after nine days because of the approach
of another hurricane.

     A Company engineer was available in the field to assist the survey team,
and the operating company provided all facilities and information needed for
a successful program.

FACILITIES AND OPERATIONS

Production From Wells

     Twenty-four wells were in production during the entire test program, and
three other wells were in production for a minimum of four days.

     All wells flowed to either a high-pressure separator, or a low-pressure
separator.  None of the production was gas lifted.  The daily production
for the nine-day period calculated from well test data averaged 874 m3/d
(5,496 bpd) of oil, 763 m3/d (4,798 bpd) of water, and 504,517 std m3/d
(17,831 Mcfd) of gas.  The calculated water cut was 47 percent.  There were
minor variations in water cut depending on which wells were in production.


                                    103
-------
     The metered oil production for the nine-day period was 895 m3/d (5,632
bpd) or 2.5 percent more than the calculated production.

Production Process System

     The flow of oil and water through the system is shown in Figure 29.
Design and operating data on major vessels are shown in Table 53.  Twelve
wells flowed'to a high-pressure two-phase separator with the liquids then
flowing to the low-pressure three-phase separator.

     Fifteen wells flowed directly to the low-pressure separator.  The crude
oil flowed from this separator to a run tank, and the water flowed to the
gun barrel.

     Miscellaneous open and closed drains discharged to sumps from which the
liquids received  were pumped to the gun barrel.  Also, water or oil could be
pumped from the run tank to the gun barrel without first draining to a sump.

     Figure 30 is a flow schematic for the water streams to and from the gun
barrel and flotation unit.  A nominal average water flow balance is presented
in the figure.

     Estimated short-duration maximum flow rates were:  froth from the flo-
tation unit, 220 m3/d; from the run tank, 360 m3/d; and from Sump 14A, 330
m3/d.

     A flotation aid, Tretolite FR-81, was added to the effluent of the gun
barrel.

     The gun barrel received primarily oily water and provided for gravity
oil separation to prepare the water for flotation.  At times, the oil content
of the gun barrel inlet was quite high because of various upsets that will be
described later.

     The gun barrel was a large rectangular vessel.  Figure 31 is a dimen-
sional sketch of the gun barrel, also showing potential flow patterns.

     The inlet distributor is located about one foot above the bottom of the
tank.  It is a cylinder with slots around the sides.  The outlet is on the
tank wall near the bottom.  The inlet distributor reduces the inlet flow
velocity and directs the flow equally around the sides.  However, there is
significant potential for short circuiting to the outlet.  A standard calcu-
lation procedure is not available to estimate the theoretical separation
capability of a gravity separator with the configuration of the ST177 gun
barrel.

     The polishing unit is a proprietary four-cell dispersed gas unit as
depicted in Figure 32 (Wemco Nozzle Air, Model 66).  The flotation unit is
very similar to the one described in Section 6 except that recycled water is
used to educt gas into the water.

     The design flow for the unit was 2,457 m3/d (15,450 bpd).  The average

                                     104
-------
WCtLS
M*




^/
H
                                            C
                                                 f
C Ml 1
o
en
                    SAMPLE POINT
               	— INTENUITTCNT fLO*
                                Figure  29.    Flow diagram,  production  process system, ST177.
-------
                               TABLE 53.   ST177  VESSEL  DATA SHEET
Vessel description
Trade Name or Vessel Type

Design Parameters
Dimensions, m (ft)
Diameter, 0.0.
Length, S.S.
Length
Width
Height
Separation Surface Area, m2 (ft2)
Total
Per Cell
Volume, m3 (bbl)
Total
Oil Phase
Mater Phase
Number of Cells
Flow Rate, «3/day (bpd)
Overflow Rate Per Cell, (n3/d)/m2, (bpd/ ft2)'3*
Recycle Rate, Percent of Flow
Retention Tine, nin.
Average Operating Parameters
Temperature, °C(°F)
Pressure, kPag. (psig)
Flow Rate, n3/d (bpd)'2*
Flow Rate, Percent of Design
Overflow Rate Per Cell. (n3/d)/m2,(bpd/ft2)
Recycle Rate. Percent of Flow
Froth Flow, Percent of Flow
VESSEL DESIGNATION ON
5A1 5A2
High pressure Low pressure
2-phase 3- phase
separator separator
Horizontal Horizontal
Cylinder Cylinder


1.8(6)
6.1(20)
_
.
-

-
-

. _
_
-
-
.
-
-
-

37.1(98.8)
7190(1040) 590(85)
-
_

-

FLOW DIAGRAM - FIGURE
a
Gravity
separator
gun barrel
Rectangular



-
.
6.86(22.5)
4.27(14)
6.15(20.2)

29.3(315)


170(1070)
54(340)
116(730)
-
.
-
-
-

36.6(97.9)
-
919(5.778)
_
31(18)
-


9
Flotation unit,
hydraulic,
dispersed gas
Uemco
Model 66


-
li
6.6(21 .8)
1.7(5.5)0)
-

11.2(120)
2.8(30)

6.8(43)


4
2460(15450)
880(515)
-
4

36.1(97.0)
-
849(5,338)
35
300(180)
510
8
1)  Separation area.
2)  Effluent flow.
3)  Overflow rate is  surface area divided by flow rate.
-------
                              GUN BARREL
                                                         FLOTATION  UNIT
FROM
L.P.   	
SEPARATOR
( 5A 20 )
   w,o
                                1
                           (a—i  )
FLOTATION
   AID
                                                  ( •—I  )  ,
  FROM
 RUN TANK
  FROM
  SUMP
                                                                         CE3D
                                                                                TO
                                                                                SEA

FLOW


mVd
bpd
5A20
763
4798
IIW-0
78
490
I4A-0
8
50
9F
70
44O
8__l
919
5778
9__l
919
5778
9__0
849
5338
                       Figure 30.  ST177 water handling system flow schematic.
-------
                         6.86 m
E
f-
                                                   OUTLET
                     TOP  VIEW
MNLET


g
in
(6







^-OIL SURFACED
50.8 cm DIA;v f
i


S
1C
i




35.6 cm
t












»



OIL /WATER




r


INTERFACE



15.2cm X 2.5cm
SLOTS
25.4 cm ^




















                                                     OUTLET
                      SIDE VIEW
             Figure 31.  ST177 gun barrel sketch.
                           108
-------
            • FHOTH OUTLET-
        SIDE VIEW

                                                      J        L
                                                        END VIEW
                                                    HCCVCLE PUMP
                                            -OUTLET
Figure 32.    ST177  flotation  unit  sketch.
-------
operating flow based on effluent flow was 849 m3/d (5,338 bpd) or 35 percent
of design flow.  The froth flow was 70 m3/d (440 bpd) or 8 percent of forward
flow.  The recycle flow was 4,360 m3/d (27,400 bpd) or 510 percent of the
forward flow.

SITE SPECIFIC TEST PROGRAM

     The planned test program for major brine samples is presented in Table
54.  The number of samples to be taken in ten days and the time the samples
were to be taken each day are listed.  Only nine days of the planned program
were completed because of a hurricane.  A limited number of tests were run
at minor sampling points not shown in Table 54.

     In addition to the brine tests, the following tests were run on crude
oil samples:  temperature, specific gravity, viscosity, boiling range distri-
bution, equilibration, and surface tension.

OPERATIONAL DATA AND OBSERVATIONS

     Measurements, observations, and records of operating conditions are
reported in this subsection.

Flow Monitoring

     No direct measurements of flow variability were accomplished on ST177.
A service representative worked with the clamp-on flow monitor on the plat-
form, but was unsuccessful.  Therefore, all reported flow data are based on
well test data or pump curves.

Well Test Data

     The well test data provided by the operator are presented in Table 55.
The data are grouped according to whether the flow was initially to the high-
pressure separator or the low-pressure separator.  The table shows which wells
flowed intermittently.

     As noted earlier, the measured oil production and the estimated oil
production from well test data differed by only 2.5 percent.  This lends
confidence to estimated water flows.

Vessel Pressures and Temperatures

     The pressure of each oil/water separation vessel was recorded twice per
day.  The temperature was recorded once per day based on the temperature of
an effluent sample.

     Table 56 presents pressure and temperature ranges for the nine-day
period.
                                     110
-------
i.e.
SEPARATOR
G/O/U
Y r^

GRAVITY
SEPARATOR


FLOTATION
UNIT
1 w-

                          TABLE  54.    ST177  TEST  SCHEDULE  FOR  THE MAJOR  BRINE TESTS
                                                 9--0
                                           No. or
                                            tests
      Tine of
       tests
                                                                                  SAMPLE POINTS
                                                                          9—1
                  No. of
                   tests
      Tine of
       tests
Mo. of
tests
                                                      V
                                                      5A20
                                                                                                                           14--0
line of
 tests
No.  of
tests
      Tine of
       tests
Field  Tests
  Infrared Oil
  Temperature
  PH
  Water Specific Gravity
  Water Surface Tension
  IR-Oil W/Sitica Gel
  IR-Oil Filtered Brine
  Susceptibility to Separation
 (1)   Field scheduled.
40
20
10
10
10
20
10
8.10.13.15
   8.10
    10
    8
    a
   8.13
    a
40   8.10.13.15
10       10
                                   (1)
  20
  10
 8,13
  10
10
          10
Laboratory Tests
Gravimetric Oil
Suspended Solids
Ionic Analysis
Bacterial Culture
Particle Size Distribution
IR-Scan of Freon Extracts

40 8,10,13.15
10 15
1 (1)
1 Ml
1 (1)
1

20
10

1
3
"

8,13
15

(1)
(1)


_
10

1
3


.
15

(1)
(1)


. «
_ _
- -
1 (1)

"" ~
                                             NOTE:   Some of  the sauries were not scheduled for a
                                                    certain  hour and are listed at the tine actually
                                                    run.  Time of tests listed is by military hour.
-------
ro
                                                 TABLE  55.   ST177  WELL TEST  DATA
Well
Fornation
flowing to Low Pressure
A-l-
A-4-
A-40
A-6-
B-3D
B-50
B13A
BI6-
C-l-
C-4-
0-4-
o-ao
0)0-
013-
Ell-
Total
F-2-H
G-4-G
F-2-H
F-2-M
£— H
F-2-H
A-5-F
G-8-E
B-l-
E---G
S-311
F-2BL
E---1
UM--P
G-a-J
(Average)
Flowing to High Pressure
A-7-
B-8-
B-9-
B-90
BI60
£-5-
£-7-
E-70
E-9-
£12-
£120
UC1-
ToUl
F-2-H
G16-II
F-2-H
0-2-H
G-2-E
D-2-J
G16-J
G20-J
G16-J
G16-C
G10-C
F-2-H
(Average)
TVO
ft
Separator
9.870
11.318
9.817
9. 857
9.372
9.373
7.236
11.370
7.428
9.452
10.613
9.983
9.435
10.536
11.733
(9.826)
Separator
9.483
13.131
8.866
7.859
10.964
7,879
12.652
12.940
12.842
11.535
11.113
9.192
(10.705)
Gas
HcT3

358
62
200
120
197
625
104
151
-
125
142
21
1.287
64
148
3.604

482
1.345
2.679
943
456
1.639
1.619
639
3.440
727
362
414
14.745
Oil
bod

430
3
607
89
20
612
22
7
0
152
12
5
746
12
215
2.932

908
345
432
15
185
11
47
70
47
24
288
508
2.880
Water
bod

13
314
912
1
483
32
73
185
0
0
845
332
187
in
9
3.497

3
1.036
4
0
554
1
1
2
1
0
0
5
1.607
lift gas
Mcfd

0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
-

0
0
0
0
0
0
0
0
0
0
0
0
-
Pressure,
SIBIIP

4.851
5.664
4.921
4.218
5.187
5.038
3.650
5.485
3.200
3.021
5.074
4.783
4.563
4.890
-
(4.610)

4.841
8.584
4.659
3.107
7.253
3.347
5,336
5.497
4.484
-
.
4.812
(5.192)
psig
FTP

1.500
850
700
350
1.000
1.400
250
375
-
400
500
300
1.550
320
700
(728)

1.750
3.700
3.200
2.550
1.500
1.900
3,300
2.700
3,500
3.400
4.450
1.850
(2.817)
Choke Size
1/64 in.

13
11
26
14
16
16
24
19
• -
15
22
22
18
21
30
(19)

19
16
12
IS
9
12
8
9
16
a
7
12
(12)
API gravity

27.8
36.1
35.0
36.5
36.7
37.7
33.7
35.6
34.9
38.9
39.2
33.8
35.4
34.7
38.4
(35.6)

37.3
34.9
37.6
37.6
36.1
34.9
44.6
37.0
38.8
51.2
34.4
35.7
(38.3)
Days of
production

All
All
All
All
All
All
All
All
All
All
All
All
All
3.7.8.9
All


All
1.2.3.6.7.8,
All
All
All
All
All
All
All
All
All
3.4.5.6.8

        Combined Total (Avg)    (10.217)   18.349   5.812
5.104
(4.853)    (1.692)
(16)
(36.8)
-------
             TABLE 56.   ST177 VESSEL TEMPERATURES AND PRESSURES
Vessel
               Pressure,
                 kPag
                (psig)
                      Temperature,
                           °C
High Pressure
Separator
              6,723-7,447
               (975-1,080)
Low Pressure
Separator
Gun Barrel
Flotation Unit
552-676
(80-98)
0
(0)
0
(0)
32.0-45.8
31.7-41.6
31.5-41.2

Pressure Drops Through System

     Table 57 traces pressure drops from the producing formations through
the system.  The table includes only the wells producing water.  The pressure
drops through the ST177 system were higher than on most other platforms.  In
particular, high-pressure drops occur at the chokes and through the high-
pressure separator control valve.  The data are recorded to permit examining
the theory that pressure drop and turbulence develop small-drop dispersions
which are difficult to remove in separation equipment.
               TABLE 57.   ST177 PRESSURE DROPS  THROUGH  SYSTEM
Location
  Pressure,
    kPag
   (psig)
    Pressure drop,
point or description
Pressure drop,
    kPag
   (psig)
Formation
(SIBHP)
Flowing Tubing
Pressure
23,080-59,187
(3,447-8,584)
 1,724-25,512
  (250-3,700)
    perforations
    static head,
    pipes
    chokes,
    valves,
    pipes
 6,785-39,667
  (984-5,753)
 3,172-18,341
  (460-2,660)
Separator
U , / C.J- / ,tt/
(975-1,080)
control valve,
pipes
1, 138-10, 101 fj!
(165-1, 465)U'
                                     113
                                                                  (continued}
-------
                             TABLE 57. (CONTINUED)

Location
Low Pressure
Separator
Pressure,
kPag
(psig)
552-676
(80-98)
Pressure drop,
point or description
control valve,
Pressure drop,
kPag
(psig)
552-676
                                       pipes
(80-98)
Gun Barrel
(1)  Range includes pressure drops from tubing to low-pressure separator.


Chemical Addition

     Three chemicals were added by metering pumps as listed in Table 58.
Demulsifier and antifoamer usage was monitored b.y measurinq the chemical level
in the feed pump reservoirs twice a day.  The water treatment chemical
usage was monitored by observing the pump down rate in a gauge glass twice
a day.

     The gun barrel is batch treated with 19 dm3  of biocide and 19 dm3  of
scale preventative twice per month.  The biocide is Tretolite X-CIDE and the
scale preventative is Tretolite SP-36.  These chemicals were not used during
the nine-day program.

Observations and Operator Reports

     An effort was made to record any event that could affect effluent water
oil content.  The operators were requested to provide information on upsets
and intermittent operational or maintenance procedures, and the survey team
made their own observations.

     All the storage tanks were filled with water as a part of the hurricane
shutdown that occurred on July 10, 1979, three days before the Program
started.  This water was pumped to the gun barrel during the first four days
of the  survey period.  Table 59 lists the quantity of bottoms pumped and the
percent oil.  The quantity of bottoms is based on a pumping rate of 359 m3/d.
The oil concentrations are based on the daily water cut test.

     Table 60 lists the percent of oil in the water dump from the low-
pressure separator.  The water dump valve on the  separator was worn and
leaked when it was in a closed position.  As a result, the valve could  not
hold an oil/water interface and oil leaked out the water dump.  The valve
was replaced with a new valve on Day 6.   The replacement and adjustment was
completed by 1700.  The Day 6, 1000 sample was taken during valve maintenanace
when there was no flow to the gun barrel.
                                     114
-------
                                      TABLE 58.  ST177 CHEMICAL ADDITION
CJ1

Chemical
Tretolite RP 2256
(Demulsif ier)
Tretolite D-91, "VEZ"
(Antifoamer)
Tretolite FR-81
Flow diagram
identifier
78
208
10
Addition rate
Addition point
Between wells and
LP Separator
Between wells and
LP Separator
Flotation Unit
Influent
dm9/d
7.6
2.0
22.3
ppmv
9.0<"
Z.3<1>
26'1'

      (1)  Based on average flow of water discharged from flotation unit.
-------
                        TABLE  59.   TANK  BOTTOMS
Day of               Hours of               Quantity                  Oil,
program               pumping                  m3/d                  percent


 01                     20                    299
 02                     24                    359                      0
 03                     24                    359                     97
 04                     14                    209                     99.6
 05                      0                      0                     52
 06                      0                      0                      3
 07                      0                      0                      -
 08                      3                     45
 09                      1                     15

Mean                     -                    143
     Well production interruptions longer than half a day are shown in Table
55.  Well 8B which produces 1,036 bpd of water was shut  in Days  4  and  5.
This reduced the produced water flow by 20 percent.  The lowest flotation
unit temperatures occurred on these days.


	TABLE 60.   ST177  LOW  PRESSURE  SEPARATOR  WATER DUMP	

                                                                      Oil,
Day                                 Time                            percent

 01                                  08                              0.3
 01                                  13                             55.0
 02                                  08                             56.0
 02                                  13                              0.5
 03                                  08                              0.3
 03                                  13                             61.0
 04                                  08                              0.3
 04                                  13                             17.0
 05                                  08                              0.4
 05                                  13                             80.0
 06                                  08                             65.5
 06                                  13                             58.0
 07                                  08                              0.5
 07                                  13                              0.6
 08                                  08                              0.3
 08                                  13                              0.4
 09                                  08                              0.2
 09                                  13                              0.5
Mean                                                                22.0
                                      116
-------
     Numerous washings occurred as shown in Table 61.  The detergent usually
used was GS1011, Heavy Duty Degreaser, from Great Southern Valve and Chemical
A solvent called Varsol from Exxon was used for turbine washings.  Tide
laundry detergent was used one day.  The washdown on Day 4 at 1300 was a
large one which used 625 dm3 of GS1011.  Washdowns and rainwater flowed to
sumps and was then pumped to the gun barrel.

                         TABLE 61.  ST177 WASHDOWNS

Day
03
04


06


07



08
Washdown
period
0600-0700
0900
1030
1300
1500
0800-0900

0430-0700

0700
1715
1200-1300
Detergent
Tide
GS1011
GS1011
GS1011
GS1011
Varsol &
GS1011
Varsol &
GS1011
GS1011
GS1011
GS1011

     Three rainstorms occurred during the program.  The day and time of these
rains are shown in Table 62.
                            TABLE 62.  ST177 RAIN
                        Day
   Time
                        06
                        07
                        08
1230-1430
1500-1600
1415-1440
     The rain on Day 8 was very heavy and occurred shortly before the 1500
sample period.  Most of the flow was to the sump.  The pumped flow from the
sump was estimated to add 330 m3/d to the flow rate to the gun barrel.  The
rain on the other two days did not occur at times that would influence the
regular effluent samples.

     The flotation unit froth flow was calculated twice per day.  The flow
varied from 0 to 134 m3/d for short periods with an average of 70 m3/d.

                                     117
-------
DATA PRESENTATION AND EVALUATION

     Comprehensive data tables are presented throughout this section.

Effluent Oil Content

     The survey of ST177 was conducted immediately following a hurricane.  The
production operations were generally upset for the first six days and rela-
tively stable for the last three.   The conditions and activities that could
affect brine quality or quality were described in the subsection on Observa-
tions and Operator Reports.  They  included pumping water from tank bottoms,
low-pressure separator level control valve failures,  detergent washdowns, and
flow increases caused by rainfall.  It was not uncommon during the first six
days for three of these events to  occur at the same time.   This made it diffi-
cult to identify a specific reason for the higher effluent oil content values.

     Table 63 presents a listing of all oil content test results.  Figure 33
is a time-indexed plot of GR-Oil in and out of the flotation unit.  Figure 34
is a similar plot for IR-Oil.

     The graphs illustrate high variability of the flotation influent for all
nine days and of the flotation effluent for the first six.  The effluent oil
content was relatively uniform for the last three days.  The effluent oil
content peaks generally correspond with influent peaks but do not match them
exactly.  The exceptionally high effluent oil  content values all occurred
during the six-day upset period following the hurricane.

     The ranges of test results are as follows:

     Flotation Effluent GR-Oil - 4 to 373 mg/1,
     Flotation Effluent IR-Oil - 28 to 542 mg/1,
     Flotation Influent GR-Oil - 147 to 2,336 mg/1,
     Flotation Influent IR-Oil - 49 to 1,990 mg/1.

     Flotation unit effluent oil content histograms are presented in Figure
35 and Figure 36.  Figure 37 is a  regression plot of  GR-Oil versus IR-Oil.
Paired GR-Oil and IR-Oil samples were taken about one minute apart from a
flowing stream.  The differences in paired test results include sampling and
testing variations.

     Table 64 presents a summary comparison of test results by the two
methods.

     The effluent oil content test results for ST177  have higher standard
deviations than most other platforms in the survey.  The ranges in test
results are wide.  The histograms  illustrate that the data are not normally
distributed.  All of this can be attributed to the general upset of operations
following the hurricane.

     The IR-Oil averaged higher than the GR-Oil.  The regression plot in
Figure 37 indicates that there is  significant correlation for results by
the two oil content procedures.

                                     118
-------
                                  TABLE 63.   ST177 MAJOR BRINE  TESTS

LP separator
effluent (SA20)
Flotation unit
influent (9--1)
Flotation unit effluent (9--0)
IR-OU w/siMcs qel
Sample ting
Day Hour
01 OB
Ot 10
01 13
01 15
02 OB
02 10
02 13
02 15
03 08
03 10
03 13
03 15
04 08
04 10
04 13
04 15
05 08
05 10
05 13
05 15
06 08
06 10
06 13
06 15
07 08
07 10
07 13
07 15
08 08
08 10
08 13
08 15
09 08
09 10
09 13
09 15
10 08
10 10
10 13
10 15
Minimum
Maximum
IR-Oil
»9/l
3.132
"/ 1 \
55(l)
"/ i \
56* l)
-
5.080
-
2.751
~ / 1 \
61(1)
-
2,709
~ / 1 V
,7(1)
-
4.233
~ 1 \\
80'"
"/ l V
66(1)
"/ 1 \
58ll)
-
4,910
-
5,842
-
3.386
-
3.979
-
2,201
-
4,656
-
-
-
-
-
2.201
5.842
G8-011
ag/1
194
.
254
-
174
-
237
-
447
.
184
-
147
.
266
.
2.336
-
301
-
1.664
'
1,010
-
336
-
198
.
175
.
305
.
399
.
187
.
.
.
-
-
147
2.336
IR-Qil
«9/>
237
288
317
144
258
330
347
182
428
271
288
216
237
385
508
322
1,609
322
440
288
1,990
49
1.185
711
516
432
309
292
758
381
322
169
212
229
330
237
-
-
-
-
49
1.990
GR-Oil
«fl/l
53
48
59
66
74
SO
78
58
221
134
107
198
373
81
68
33
17
141
25
20
74
26
28
102
41
14
21
9
9
12
12
9
10
16
4
9
_
-
-
-
4
373
iR-on
«9/l
67
89
85
79
83
82
106
89
334
195
135
271
542
152
114
61
37
63
51
39
78
47
169
47
63
34
36
30
33
30
28
30
30
31
28
29
-
-
-
-
28
542
Dispersed
mg/1
68
-
76
-
68
-
55
-
313
_
127
-
508
-
76
_
17
-
30
-
59
-
129
-
49
-
20
.
17
-
12
-
14
-
10
-
-
-
-
-
10
508
Soluble
ng/1
0
.
9
.
15
-
51
-
21
_
8
.
34
.
38
.
20
-
21
-
19
-
40
-
14
-
16
_
16
-
16
.
16
-
18
-
-
-
-
-
0
51
Filtered
brine
IR-01)
mg/1
44
-
-
-
46
-
-
-
79
.
_
-
131
-
-
-
56
-
-
-
452
-
-
-
50
-
-
-
42
-
-
-
47
-
-
-
-
-
-
-
42
452
Surface
tension
dynes/en
60
.
.
.
74
-
-
.
62
_
_
.
50
.
.
.
74
-
-
-
55
-
-
-
76
-
-
-
78
-
-
-
78
-
-
-
-
-
-
-
50
78
Flow rate
OutlZ)
«3/d
.064
.064
.064
.064
.152
.152
.152
.152
807
807
807
807
637
637
637
637
629
629
629
629
842
-
842
842
813
813
813
813
866
866
866
866
828
828
828
828
-
-
-
-
629
1,152
SUmnings
«3/d
47
47
47
47
47
47
41
41
41
41
41
41
41
41
128
128
128
128
134
134
30
-
71
71
74
74
74
74
68
68
68
68
90
90
90
90
-
-
-
-
30
134
!1)  Oil  content reported in percent as measured by the water cut test.
2)  Based on well test data.
-------
r-o
o
             60O-
             7OO-
             6OO-
             500-
       GR-OIL
        mg/l
             4OO-
             3OO-
             2OO-
             tOO-
                                                4
5        6

    DAY
10
                          Figure  33.   ST177  flotation unit performance, GR-oil vs  time.
-------
IR-OIL



 mg/l
        eoo-
       7OO-
        600-
        5OO-
4OO-
       3OO-
       2OO-
        IOO-
                                                      DAY
                                                                                                10
                    Figure  34.  ST177 flotation unit performance,  IR-oil  vs  time.
-------
  30
o

U)

o
UJ
a:
u. io
                                      ll    '      '          •
                                   36

                                   64
                                 I OF 36 VALUES IN MEAN

                                 OVER 3OO mfl/1
           ml  I  In.  m
             50        100
       IU1
  ISO        200

GR-OIL^mg/l
              T  I  I  i  I  i  r

                 250        300
       Figure 35.  ST177 flotation unit effluent, GR-oil histogram.
  30 —'
  20
U
z
UJ

a
UJ
x
u. 10
                                                i
                                   95
2 OF 36 VALUES IN MEAN

OVER 3OO
 .fn..np.n..n
100        150       20<
                                                       ji
    0  '  '  ' '  50
   150       200

IR-01LfmQ/l
                  250
                               300
       Figure 36.  ST177 flotation unit effluent, IR-oil histogram.
                               122
-------
ro
co
                200
                150
        GR-OIL

         mg/l
                100
                  o
                          GR-OIL * 0.048 +0.67 (IR-OIL)
                               t » 0.93
                          5.6% OF DATA INCLUDED IN
                          EQUATION OFF GRAPH
                     j	I
                                                                   I   I   I  I
                                                       II   I  i   i
                   O
50
100             150
        IR-OIL  mg/l
200
                                                                                              250
                   Figure 37.   ST177 flotation unit effluent, infrared-gravimetric regression.
-------
                  TABLE 64.  ST177 FLOTATION UNIT EFFLUENT
                        GR-OIL AND IR-OIL COMPARISON



Number of tests,
Mean, (x), mg/1
Minimum, mg/1
Maximum, mg/1


(n)



Standard Deviation ,(s), mg/1
Oil
GR-Oil
36
64
4
373
74
content
IR-Oil
36
95
28
542
103
Number, (n)
Mean of Differences, (A), mg/1
Standard Deviation, (s^), mg/1
Paired tests

     36
     38
     37
     All oil content tests for dispersed oil and
the IR-Oil w/Silica Gel test are listed in Table
tests is presented in Table 65.
           soluble oil as
           63.  A summary
measured
of these
by
                      TABLE  65.   ST177  SOLUBLE  OIL  SUMMARY

Analysis or test
IR-Oil (1)
Dispersed Oil
Soluble Oil
Flotation effluent
Range Mean
mg/1 mg/1
28-542 113
10-508 92
0-51 ' 21
Proportion
of total ,
percent
100
81
19

(1)  Includes only 18 test results when IR-Oil w/Silica Gel tests were
     obtained on same sample.


     On average, 19 percent of the oil in the effluent was soluble oil and
81 percent was dispersed.

     Linear regression plots of dispersed oil versus IR-Oil and GR-Oil are
presented in Figure 38.  Extrapolation of the regression lines to zero
dispersed oil indicate a residual IR-Oil of 18 mg/1 and a residual GR-Oil
of 6 mg/1 after all dispersed oil has been removed.
                                      124
-------
       175
       ISO
        125
TOTAL
 OIL  100
mg/1
        75
        50
        25
          I   1  1   I     1   I  I   I
                                                     I   I  I      I  I   I  I
I  I
• TOTAL IR-OIL VS  DISPERSED  IR-OIL
  TOTAL IR-OIL * 18+1.0 (  DISPERSED  IR-OIL)
            r * 1.0

• TOTAL GR-OIL VS  DISPERSED GR-OIL
  TOTAL GR-OIL • 6.3+0.70 { DISPERSED  IR-OIL)
            r * 0.97
  11.1% OF DATA INCLUDED IN  EQUATIONS
  OFF GRAPH.
                       TOTAL IR OIL-  DISPERSED   IR-OIL
                                              TOTAL GR OIL-  DISPERSED  IR-OIL

            j	I
   !  I   I  I   I  I   I  I   I   I  I   I  I   I  I   I  I   I  I   I  I   I  I   t  I
       25           50          75           100           125
                 DISPERSED  IR-OlUmg/l

  Figure 38.   ST177 flotation unit effluent,
     total  oil - dispersed oil regression.
                                      125
-------
Surface Tension

     All surface tension test results are reported in Table 63.  The mean
surface tension of the flotation effluent was 67 dynes/cm with minimum and
maximum values of 50 and 78 dynes/cm.  The linear regression equation for
effluent IR-Oil and surface tension is:

               IR-Oil = 924-11.6 (Surface Tension)
                    r = 0.70

     A decrease in IR-Oil is indicated when surface tension increases.

Suspended Solids

     Suspended solids test results are listed in Table 66 for major sampling
points.  A suspended solids summary for ST177 is presented in Table 67.

     More than half of the solids are Freon soluble.  All solids decrease
across the flotation unit.

     Figure 39 presents time-indexed plots of Freon insoluble suspended
solids in the flotation influent and effluent, and of flotation effluent
dispersed oil.  The suspended solids samples were taken at 1500 each day and
the dispersed oil  samples were taken at 0800 and 1300 each day.

     The plotted data do not demonstrate a distinct pattern that the dis-
persed oil  content of the effluent is higher when flotation influent or
effluent suspended solids are higher.  The lack of a readily apparent rela-
tionship may be because the samples were not all taken at the same time and
also because of the substantial  variability of the suspended solids test.

Filtered Brine

     The filtered brine IR-Oil content of ST177 effluent was in the range
of 42 to 452 mg/1.  Four of nine filtered brine test values were higher than
the corresponding unfiltered IR-Oil test values.  The other five were lower.
Conclusions cannot be drawn from the filtered brine test results because of
the inconsistent pattern of the data.

Flotation Unit Performance

     Figure 40 is a regression plot of IR-Oil in and out of the flotation
unit.  The plotted data and the regression equation indicate that effluent
oil content is essentially independent of influent oil content.  The slope of
the regression line is -0.015 and the correlation coefficient is -0.059.

     Figure 41 is a regression plot of flotation effluent IR-Oil and percent
hydraulic loading.  The plotted data appear to indicate essentially no cor-
relation between oil content and hydraulic loading.  The calculated regression
relationship indicates oil content decreases as hydraulic loading increases
with minor correlation.  This intuitively false indication may be because
many upsets occurred, short term flow variations were not measured, and the

                                     126
-------
TABLE 66.  ST177 SUSPENDED SOLIDS TESTS




Low pressure separator,

Sample time
Pay Hour
01 15
02 IS
03 IS
04 15
05 15
06 15
07 15
08 15
09 15
10 15
Minimum
Maximum

To til
*g/t
Ml
114
75
87
117
82
125
85
54
-
54
141
Freon
soluble
mg/1
102
90
59
68
96
51
76
57
46
-
46
102
Freon
insoluble
W9/1
39
24
16
19
21
32
SO
28
8
-
9
50



, out (5A20)
Acid
soluble
1*9/1
2
5
3
10
6
3
8
11
6
-
2
11

Fixed
"9/1
37
20
14
9
15
29
42
17
2
-
2
42

Total
MQ/1
114
126
102
81
117
104
840
304
118
-
81
840





•Flotation unit, in [9— i)
Freon
soluble
»g/l
94
94
78
63
99
85
760
291
96
-
63
760
Freon
Insoluble
mg/1
21
32
24
18
18
19
80
13
22
-
13
80
Acid
soluble
mg/1
6
12
12
4
3
5
24
6
4
-
3
24

Fixed
mg/1
15
20
13
14
15
14
57
7
18
-
7
57

Total
»g/1
211
78
77
23
27
18
25
18
18
-
18
211


Flotation unit, out
Freon
soluble
mg/1
188
60
59
17
20
13
18
13
12
-
12
188
Freon
insoluble
mg/1
23
18
18
6
7
6
7
5
6
-
5
23

(9--0)
Acid
soluble
mg/1
5
11
12
3
4
5
1
2
2
-
1
12



Fixed
ntg/1
18
7
6
3
3
1
6
3
4
-
1
18
-------
                  TABLE 67.  ST177 SUSPENDED SOLIDS SUMMARY
                                       Average suspended solids, mg/1
Suspended Solids                       5A20        9—i          9--0
Total
Freon Soluble
Freon Insoluble
Acid Soluble
Fixed
98
72
26
6
21
212
184
27
8
19
55
44
11
5
6

Note:  Some numbers do not check because of rounding.

calculated flows were in the narrow range of 26 to 47 percent of the flotation
unit design capacity.

Gun Barrel Performance

     Thirty-six IR-Oil tests and eighteen GR-Oil tests were run on the gun
barrel effluent.  There was a common sampling point for the gun barrel
effluent and the flotation unit influent.  The test results for this sample
point (9—i) are listed in Table 63.

     The IR-Oil content of the gun barrel effluent was in the range of 49
to 1,990 mg/1 with a mean of 432 mg/1.   The sample on which the IR-Oil
content of the 49 mg/1 was determined was taken at a time when there was no
flow to the gun barrel.  Excluding this value, the lowest IR-Oil was 144 mg/1.
The lines labeled "influent" in Figure 33 and Figure 34 illustrate sample-to-
sample variations in oil content.

     The results of two susceptibility to separation tests on the gun barrel
effluent are reported in Table 68.  The mean IR-Oil content after five minutes
of static settling for the two tests was 210 mg/1.  For comparison, the IR-
Oil content of the gun barrel effluent was in the range of 169 to 758 mg/1
for the two days when the settling tests were run.

     The largest oil drop detected by the particle size test in the gun
barrel effluent had a diameter of 55 ym.

Miscellaneous Brine Tests

     All other brine test results for ST177 are listed in Tables 69, 70, 71,
and 72.  The results for the following tests were in narrow ranges for all
samples:  temperature, pH, and specific gravity.  These parameters were
therefore not examined for correlation with sample-to-sample variations in
effluent oil content on ST177.  These parameters will be discussed with
respect to variations between platforms in Section 17.
                                     128
-------
                125
                100
ro
UJ
            75



CONCENTRATION

    mg/i


            so
                 25
                                             I
                               EFFLUENT S.3.
                                      EFFLUENT
                                      DISPERSED
                                          OIL
                                                           5        6

                                                              DAY
                                                                                                   10
                         Figure 39.   ST177 flotation unit Freon  insoluble suspended solids.
-------
co
o
           200
        o>
        E
        UJ
u.  too
Ul
t
z
        z
        o
        g
        O  50
        U.
                 I  I  I  I  I   I  I   I  I  I   I  I
                                     TT
                I  I   I  I
I  '  '  '   '  I
I  II  I
I  I  I  I
I  I  I
                                                               IR - OIL out = 102-0.013 (IR-OIL in)
                                                               r-0.059
                                                               16.7 % OF DATA INCLUDED IN
                                                               EQUATION OFF GRAPH
                I   I  t   t  I  t  I  I   I  I  1  I  i   t  I  I  i  I   I  I   I  i   i  i  I  i  I   i  I  I   I
              O
                 100
200         300          40O         SOO         6OO
     FLOTATION  UNIT  INFLUENT  IR-OIL.mg/l
                                                                                                 70O
                              Figure  40.   ST177 flotation unit  in-out  IR-oil  regression.
-------
                     20O
to
         FLOTATION
           UNIT
         EFFLUENT

          IR-OIL
           IDQ/I
                     ISO
100
                      50
T  I  I   I
j  I  I  I
                            I
                                                       I  I
I  I
      IR-OIL: 180 -2.5 (HYDRAULIC LOADING)
      r • 0.16
      8.3% OF DATA INCLUDED IN EQUATION
   -  OFF GRAPH
                          111  I  I   I  I  I   I  I
                                               t  i  i
•  I  I  •   1 -1  •  I
                                             I
                                   10
                         20          3O          4O          SO
                                HYDRAULIC  LOADING . %
                                                         60
                 Figure 41.   ST177  flotation  unit,  hydraulic  loading - infrared oil  regression.
-------
                    TABLE  68,   ST177  GUN  BARREL  EFFLUENT
                        SUSCEPTIBILITY  TO SEPARATION
          Sampling  time
                                            T^st number
             Mean
Day
Hour
Minute
7
9
30
8
9
30
.
_
-
          Settling  time,
            minutes	

            0-1  (1)
              5
              15
              30
              60
            120
IR-Qil.  mq/1
495
271
178
131
114
114
186
148
110
84
85
85
340
210
144
108
100
100
     (1)  The actual settling time is the time required to handle  the
         separatory funnel after filling and to draw a sample, and  is
         estimated at  not more than one minute.

     Only one ionic  analysis  test and  one  sulfate  reducing bacteria  test per
sample point were run  on ST177.   These tests also  are only significant with
respect to comparisons  between  platforms.

Crude Oil Tests

     All crude oil  test results  are  listed  in Table 73 and Table  74.  The
crude oil temperature,  specific  gravity,  and surface tension test results all
fell in narrow ranges.

     The viscosity and  boiling  range distribution  tests were limited in
number and are of primary significance for  comparisons between platforms.
Two equilibration tests were  run.

     The limited number of tests  run on crude oil  provided only a limited
characterization of the crude oil.
                                     132
-------
                                   TABLE 69.ST177  SUPPLEMENTARY  BRINE  TESTS
co
CJ

Sample
Day
01
01
02
02
03
03
04
04
05
05
06
06
07
07
08
08
09
09
10
10
Mean
Minimum

time
Hour
08
10
08
10
08
10
08
10
08
10
08
10
08
10
08
10
08
10
08
10


Maximum





Temperature, °F
14--0

30.4
-
29.8
-
33.0
-
32.0
-
29.4
-
29.0
-
27.5
-
29.0
-
29.0
-
-
30.0
27.5
33.0
5A20

45.2
-
45.8
-
35.0
-
34.3
-
32.1
-
32.0
-
38.0
-
36.0
-
35.3
-
-
37.1
32.0
45.8
9F-0

40.3
-
40.5
-
40.8
-
32.4
-
31.5
-
35.0
-
36.5
-
36.0
-
35.0
_
-
36.4
31.5
40.8
9— i

40.9
-
41.6
_
41.1
-
32.5
-
31.7
-
35.4
-
36.2
-
35.7
-
34.5
_
-
36.6
31.7
41.6
9--0
38.8
40.7
39.4
41.2
38.8
40.5
32.4
32.6
31.5
31.6
34.8
35.2
35.0
36.5
34.8
35.6
35.7
35.2
_
-
36.1
31.5
41.2

pH
9--0

6.4
-
6.4
-
6.2
-
6.2
-
6.4
-
6.4
-
6.2
-
6.4
-
6.4
-
-
6.3
6.2
6.4

(1)
Specific
gravity
9—0
1.168
-
1.163
-
1.163
-
1.135
-
1.129
-
1.152
-
1.158
-
1.148
-
1.145
-
_
-
1.151
1.129
1.168

                   Note:    Sample point identification numbers as shown on flow diagrams.


                   (1)      Specific gravity is reported at temperature shown in table above.
-------
               TABLE  70. ST177 SULFATE REDUCING BACTERIA
                                      Bacteria  per  nriTHIiter

Sample point                      Sample No. 1       Sample No. 2
Flotation Unit - Out  (9—0)            0                  0
Flotation Unit - In  (9—1)             0                  0
LP Separator - Out  (5A20)               0                  0
Sump  - Out  (14--0)                   10,000              1,000

Sample Day and Hour:  09 at 15
	TABLE 71.   ST177  MATER  CUT AT  VARIOUS SAMPLE POINTS


                                      Water cut,  %	
Sample time            Flotation unit      Oil storage      Sump
Day    Hour                froth             bottoms        out
01      10                   100                  -           91
02      10                   100                100           77
03      10                    93                  3           36
04      10                     -                  0           86
05      10                   100                 48            6
06      10                    97                 97           80
07      10                   100                  -          100
08      10                   100                  -          100
09      10                   100                               2

Mean                         99                 50           70
Minimum                     97                  02
Maximum                    100                100          100
                                  134
-------
	TABLE 72.   ST177 IONIC ANALYSIS FLOTATION  UNIT EFFLUENT

Constituent                                  Concentration, rng/1
Sodium (Na)                                         97,000
Calcium (Ca)                                         1,500
Magnesium (Mg)                                         310
Barium (Ba)                                            750
Chloride (Cl)                                      111,000
Sulfate (S04)                                          245
Alkalinity   (as HCOO                                 584
Iron (Total)        J                                   26
Sulfide (as H2S)                                         0.94

Total Dissolved Solids
     Summation         .                            211,000
     Gravimetric                                   203,000

Sample Day and Hour:  09 at 15
                               135
-------
           TABLE 73.  ST177 CRUDE OIL MISCELLANEOUS TESTS
                                                          (1)

Sample time
Day Hour
01 08
02 08
03 08
04 08
05 08
06 08
07 08
08 08
09 08
Mean ^
Minimum
Maximum
Temperature
°c
33.4
31.0
31.7
31.5
32.6
35.0
33.8
32.1
35.4
32.9
31.0
35.4
Specific^
gravity
0.846
0.848
0.846
0.830
0.838
0.834
0.838
0.840
0.857
0.842
0.830
0.857
Surface tension^ '
dynes/cm
30
30
29
30
29
29
30
29
30
30
29
31
Sample time
Day    Hour
09
15
                  Viscosity at 37.77°C
                Kinematic        Absolute
               centistokes       centipoise
4.05
3.47
Oil/Water Ratio
IR-Oil, mg/1
                          Equilibration at 82°C
                        Brine TDS = 100,000 mg/1

                        Test No. 1    Test No. 2
                   4/1
                    31
               4/1
               17
(1)  Samples taken from LACT unit.
(2)  Reported for approximately the temperature in table,
                                  136
-------
        TABLE 74.   ST177 CRUDE OIL BOILING RANGE DISTRIBUTION


Initial

Boilinq Point. °C
Final Boiling Point, °c
Boiling
Below -
200 -
250 -
300 -
350 -
400 -
450 -
500 -
range, °C
200
250
300
350
400
450
500
550
Run No.
150
490

43.1
10.6
19.4
13.4
6.8
5.5
0.8
0.4
1 Run No. 2
150
470
Percent recovered
42.4
10.4
19.2
12.5
6.4
8.3
0.8
0.1
Mean
150
480

42.8
10.5
19.3
13.0
6.6
6.9
0.8
0.2
Total
Sample Day and Hour:    09  at  15
100.0
100.1
100.1
                                 137
-------
                                  SECTION 9

                                PLATFORM BM2C
GENERAL

     The ten-day testing survey was conducted on Platform BM2C from March 4,
1980 through March 13, 1980.

     A description of the production facilities, the test program, and data
presentation and evaluation are presented in this section.

     Four survey team members arrived at the platform on March 3 and the test
equipment was set up the same day.  Oil  company personnel unloaded the equip-
ment and provided living quarters, work  space, sample taps, a flow monitor
and the utilities needed to conduct the  program.

     Transfer of equipment to the platform was delayed for two days by high
waves.  After testing started on March 4, the weather did not interrupt the
sampling schedule.  The minor operational problems that occurred also did not
interrupt the schedule.

FACILITIES AND OPERATIONS

Production From Wells

     The number of wells flowing to the  production system varied from day to
day.

     Four gas-lift wells were produced only a few hours on the first day and
then again on the ninth and tenth days.   One of the compressors supplying the
lift gas was out of service for repairs  during the non-productive period.

     Twenty-three wells were produced continuously for the ten-day survey
period.  Two other wells were produced intermittently on the fifth, sixth,
and seventh days.

     The estimated daily production of the twenty-three wells that were pro-
duced continuously was 1,901 m3/d (11,957 bpd) of crude oil, 720 m3/d (4,526
bpd) of water and 370,530 std m3/d (13,085 Mcfd) of gas based on well test
data.  The calculated water cut was 27 percent.

     Twenty-five percent of the oil was  gas lifted, and 58 percent of the
water was gas lifted.


                                     138
-------
Production Process System

     The flow of oil  and water through the system is shown in Figure 42.
Design and operating  data on major vessels are presented in Table 75.  The
primary oil/water flow is to a low-pressure three-phase separator.  The flow
from one well producing primarily gas and water went first to a high-pressure
gas/liquids separator before the liquids flowed to the low-pressure separator.

     The oil stream from the low-pressure separator passes through an electro-
static oil treater for additional brine separation.  The crude oil is then
pumped to a pipeline for sale.

     A demulsifying agent, Tretolite RP-34, is added to the low-pressure
manifold ahead of the low-pressure separator at the rate of 15 dm3/d (4 gpd).

     Figure 43 is a flow schematic for the water handling system.  The pri-
mary produced water flow is from the low-pressure separator to the corrugated
plate interceptor (CPI), to the flotation unit, and then to discharge.

     Skimmings from the CPI and the flotation unit flow to a large wet-oil
tank.  Miscellaneous  drains discharge to skim sumps, and any oil  recovered
is pumped to the wet-oil tank.  Oil and water that accumulate in  the wet-oil
tank are pumped to the oil treater.  The water settling in the oil treater
flows to the inlet of the CPI.

     The flow was monitored continuously with an orifice plate meter on the
CPI inlet.  The skimmings flow from the CPI and the flotation unit were
estimated based on the time to fill a measured volume in the wet-oil  tank.
The effluent flow was calculated by subtracting the skimming flows from the
CPI inlet flow.

     The average flow rates reported in Figure 43 are based on averaging
thirty-four measured  and calculated values corresponding with sampling  times.
The flows are higher  than those estimated from well test data. The differ-
ences could be because the flows at the sampling times were higher than
24-hour average flows, or the differences could be attributed to  inaccuracy
of flow estimates based either on monitoring or on well  test data.

     A water treating chemical, Tretolite FR-87, is added to the  flotation
unit inlet at the approximate rate of 17 dm3/d (4.5 gpd).

     The CPI unit is  a gravity separator of proprietary design supplied by
Monarch Separators, Inc.  Oil separates as the water flows between parallel
plates spaced approximately 2 cm (0.75 in.) apart.  Figure 44 is  an undimen-
sioned representational sketch of a CPI unit.

     The CPI unit on  BM2C is a 2-pack unit.  The approximate dimensions of
each pack are 1 m high, 1 m wide, and 1.75 m long.  Based on the  manufac-
turer's recommended sizing procedure and the conditions prevailing on BM2C
during the survey, the CPI on BM2C should accomplish separation of 30-um
oil drops at a flow rate of 981 m3/d (6,170 bpd), or separation of 40-um
oil drops at flow rates up to 1,908 m3/d (12,000 bpd).  Average hydraulic

                                      139
-------
GD
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LEO
GD



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hi.


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GD



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-------
TABLE 75.  BM2C VESSEL DATA SHEET

5A1
High pressure
gas/liquid
Vessel description separator
[rade Name or Vessel Type Horizontal
Cylinder
lesign Parameters
Dimensions, m. (ft)
Diameter, O.D.
Length, S.S.
Length
Width
Height
Separation Surface Area, n2. (ft2)
Total
Per Cell
Separation Volume, m3. (bbl)
Total
Water Phase
Number of Cells
Flow Rate, m3/day, (bpd)(2*
Overflow Rate Per Cell,(w3/d)/m2.(bpd/ft2) «)
Recycle Rate, Percent of Flow
.. Retention Time, nin
ye rage Operating Parameters
Temperature. °C(°F)
Pressure. kPag (psig) 12.710(1.844)
Flow Rate. «3/d(bpd) ^
Flow Rate, Percent of Design * '
Overflow Rate Per Cell, (»3/d)/m2,(bpd/ft2)<2*
Recycle Rate, Percent of Flow
Froth Flow. Percent of Flow
,U Proprietary unit with two plate packs.
2 Based -M effluent flow.
3 Based on removing 40 urn oil drops.
4 Overflow rate is surface area divided by flow rate.
VESSEL DESIGNATION ON FLOW DIAGRAM -
5A2 6
Low pressure Oil treater,
3-phase chem
separator electric
Vertical Cylinder Horizontal
Cone-Bottom Cylinder


4.88(16) 4.27(14)
10.67(35)
9.14(30)
,
-

18.7(201)
.

-
29.3(184)
_
•
-
-
-

46(115)
531(77) 462(67)
995(6.257) 242(1.521)
_
53(31)
-
-




FIGURE 9-1
8
Gravity
separator,
CPI
Monarch '



-
.
.
.
.

.
_

.
-
_
1.908(12.000)^
-
-
-

46(115)
0(0)
1,160(7.294)
_
-
-
-





9
Flotation unit.
mechanical .
dispersed gas
Wemco
Model 76


-
-
7.9(26)
1.98(6.5)
-

15.7(169)
3.9(42)

11(71)

4
4.090(25.725)
1.049(612)
-
4

45(113)
0(0)
995(6.257)
24
255(149)
-
17




-------
              OIL TREATER
       CPI GRAVITY

        SEPARATOR
FLOTATION UNIT
                                                          FLDTATION AID
        FROM L.P. SEPARATOR
IM
                               r  (  a—. )
                       FROM SUMPS
                                 WATER
                                 FLOW
                                                                    ~n
                                          WET OIL TANK
       BF   8	I  9F  9	1   9	0

       TT   I23T   165   1160    995

bpd     484  7TT8   1037  T294    6257
                                                                                                          TO
                                                                                                         SEA
                          Figure 43.   BM2C water  handling  system  flow  schematic.
-------
OUTLET
 WEIR
                                 OIL OUTLET
                                      GAS VENT
 WATER
OUTLET
  CORRUGATED
  PLATE PACK
      [OIL

      (WATER

       SAND/
       SLUDGE
INLET WATER
  PRIMARY
SAND OUTLET
  SECONDARY ~
SAND 8 SLUDGE
   OUTLET _
         Figure 44.  8M2C corrugated plate interceptor sketch,
                             143
-------
loading was estimated to be 1,160 m3/d (7,294 bpd), or 580 rrr/d per plate
pack.

     The flotation unit (Wemco 1+1, Model  76) on BM2C is a proprietary four-
cell unit with mechanical  gas eduction.   This type of unit was described in
Section 6 and is depicted in Figure 6.

     The unit is designed to handle 4,090 m3/d (25,725 bpd) of water.   The
average loading was 995 m3/d or 24 percent of design.

SITE SPECIFIC TEST PROGRAM

     The planned test program for brine  samples is presented in Table  76.
The number of samples to be taken in ten days and the time the samples are to
be taken each day are listed.  The listed program was carried out with only
minor variations as noted below.

     In addition to the brine tests, the following tests were run on crude
oil samples:   temperature, specific gravity, viscosity, boiling range  distri-
bution, equilibration, and surface tension.

OPERATIONAL DATA AND OBSERVATIONS

     Measurements, observations and records  of operations are reported in
this subsection.

Flow Monitoring

     The flow rate was monitored continuously at the CPI inlet as described
in the subsection on the process system.  Using this measured flow rate and
the estimating procedures previously described, a flow rate was estimated
and recorded each time a sample was taken at the following points:  CPI inlet,
outlet, and skimmings; flotation unit inlet, outlet, and skimmings.  The data
for the flotation unit are listed in Table 77.

     Because of orifice plate changes, the flow monitor was not fully  opera-
tional  until  the middle of the second day.

     The water flow patterns were presented  in Figure 42 and Figure 43.
The primary continuous flow was produced water from the wells.  The primary
recycle flow was the water returned to the oil treater from the wet-oil tank.
When the wet-oil tank recycle pump came  on,  the flow at the CPI inlet
increased by about 709 m3/d (4,460 bpd).  The recycle pump would be off for
several hours and then on for several hours.  The on/off durations did not
follow a set pattern.

Well Test Data

     The well test data provided by the  operator are presented in Table 78.
Data on wells from remotely located Platform E are not included.  Two  Plat-
form E wells flowed to BM2C intermittently on Days 5, 6, and 7.  The two E
wells were known high-water producers estimated at rates over 159 m3/d

                                     144
-------

L.P.
SEPARATOR
G/O/U
T
OIL
TREATER
\
r-O
r .


GRAVITY
SEPARATOR
w


FLOTATION
UNIT
I w-

                                  TABLE  76.   BM2C TEST  SCHEDULE  FOR  THE MAJOR BRINE  TESTS
field Tests
  Infrared Oil
  Temperature
  pll
  Water Specific Gravity,,
  Mater Surface Tension*  '
  IR-Oil  U/Silica Gel
  IR-Oil  Filtered Brine       ,,
  Susceptibility to Separation1

Laboratory Tests
  Gravimetric Oil
  Suspended Solids
  Ionic Analysis
  Bacterial Culture         ...
  Particle Size Distribution1*'
                                                                                     SAMPLE POINTS
                                                  V
                                                   9--0
                                                                        V
                                          V
                                               V
                                               6--0
                                               V
                                               5A20
No. of
tests
Time of
tests
No. of
tests
Time of
tests
No. of
tests
Time of
tests
No. of
tests
Time of
tests
No. of
tests
Time of
tests
                                               40
                                               10
                                               10
                                               10
                                               10
                                               20
                                               20
a,10.13.is
    a
    8
    8
    8
   8.13
   8.13
40    8.10.13.15
10       8
20
10
                      10
                      10
                      10
                       3
8.13
  a
         8
         8
         8
         13
                                               40   8.10.13.15       10        8            -        -
                                               10        a           10        a           to        8
                                                1       (1)           -                     -
                                               A maximum of five tests at sample paints selected in the field.
                                                3       13            3       13            3       13
(U
(2)
(3)
(4)
     Sampling times not  shown will  be  field scheduled.
(2)   Extra samples when  IR-Oil is high.
     IR-Oil w/silica gel at 0. 5. and  120 minutes.
     IR-Oil. IR-Oil w/si)ica gel. and  filtered brine  tests at same time.
                                    NOTE:   Time of tests listed Is by military hour.
-------
                                              TABLE  77.    BM2C  MAJOR BRINE  TESTS
Gravity separator influent
Samgle tine
Day Hour
01 08
01 10
01 13
01 IS
02 08
02 10
02 13
02 15
03 08
03 10
03 13
03 15
04 08
04 10
04 13
04 15
05 08
05 10
05 13
05 IS
06 08
06 10
06 13
06 15
07 08
07 10
07 13
07 IS
08 08
08 10
08 13
08 15
09 08
09 10
09 13
09 15
10 08
10 10
10 13
10 15
Minimum
Maximum
IR-Otl
mg/1
555
840
.
609
.
529
-
824
_
525

340
_
197
_
357
.
185
-
311

248

563
-
538
_
420
_
487
.
580
.
454
_
563
.
647

185
640
IR-Oil w/silica gel
MHsperseo* "5STuFJeir
«g/l
420
_
504
.
.
_
681

.
_
256

_
_
101

.
-
193

_
„
471
.
_
_
231

.
,
471

_
„
462

„
•
101
681
mg/1
135
.
105
.
.
-
143
.
_
.
84
_
.
.
256
.
.
.
116
.
.
_
92
.
.
_
189
.
.
_
109
.
.
.
101
.
_
-
84
256
(8-1)
Filtered
brine
IR-011
Flotation unit
influent (9-1)
Surface
tension
Flotation unit effluent (9--0)
IR-Otl w/sillca gel
GR-011
IR-011
GR-011 IR-011 Dispersed
ng/1 dynes/en ng/1 mg/1 mg/1 my/1
63
.
71
-
.
.
55
-
.
.
59
.
.
.
55
-
-
-
56
.
.
_
59
-
.
.
227
-
-
.
261
.
.
.
277
-
-
-
55
277
57
.
49
_
50
.
53
.
60
„
54
.
49
.
51

45
_
48
_
51

52
.
42
_
55
.
56
_
51

50
.
55
.
59

42
60
-
_
74
_
-
.
110

r
_
129
.
-
_
135

_
-
57
.
.
_
114
„
.
..
138

.
^
174

_
_
106
.
.
-
57
174
75
84
118
97
92
88
168
164
261
189
240
80
101
105
202
75
84
109
84
92
101
168
134
252
252
126
219
210
219
219
252
210
130
130
143
210
227
286
75
286
275(B)
22
28
21
26
24
97(8)
27
18
22
17
16
17
179(B)
12
17
17
22
IS
20
17
20
26
19
20
21
15
26
18
29
24
23
20
22
25
26
52
ia
126(8)
12
52
37
39
40
35
50
42
40
48
39
40
38
37
34
39
33
40
35
39
34
34
35
37
33
SO
41
40
38
45
8(A)
42
40
42
44
42
39
38
38
38
34
33
SO
ng/1
1
13
-
5
-
5
.
17
.
2
.
4
-
2
_
0
.
1
.
1
.
3
.
8
.
3
.
17
-
2
.
5
-
8
.
0
-
2
-
0
17
Soluble
36
26
-
30
-
37
-
31
-
38
-
33
-
37
-
40
-
38
-
36
-
34
.
42
-
37
-
28
-
40
-
37
-
34
.
38
-
36
-
26
42
Filtered
brine Surface
IR-011 tension
mg/1
54
45
-
71
-
S3
-
22
-
55
-
52
-
56
-
0(A)

44
-
46
-
51
-
55
-
54
-
57
-
59
-
51
-
55
-
45
-
51
-
22
71
dynes/ci
70
-
60
-
-
-
60
-
-
-
58
.
-
-
57
-
-
-
59
.
-
-
45
-
-
-
64
-
-
-
62
-
-
-
60
-
-
-
45
70
Flov
ETH
• m3/d
-
-
-
-
1.139
834
1.139
834
834
834
834
1.139
774
774
834
1.172
1.172
741
1.199
1.199
899
899
774
774
774
1.172
752
719
752
752
1.161
1.161
1.580
1.580
1.428
1.063
1.063
1.063
719
1.580
4 rate
SMyrtngs
-
-
-
-
327
109
327
109
109
109
109
327
109
109
109
327
327
109
327
327
109
109
109
109
109
327
33
33
33
33
55
55
327
327
327
76
76
76
33
327
(A)  Nat included In statistical analysis.
(B)  Not included in statistical analysis.
Appears Inconsistent with other IR-Oil. GR-Oil and "soluble" oil tests.
Salt crystals were observed after freon was  evaporated for the test.
-------
TABLE 78. BM2C WELL TEST DATA
Well
flowing to High
C-B-
Flowlng to tow
C-1A
C-2-
C-3-
C-4-
C10-
C14-
C16-
0-40
D-SO
0-6-
012-
013-
015-
017-
021-
0280
Total (Average)
Flowing Total
formation
Pressure
-Q-RA
Pressure
010RD
P-1RA
-0-RO
-D-RO
-0-RO
-NBRA
-D-RO
-0-RD
-0-RD
-P-RC
010RB
.
D12RB
012RB
-0-RO
_


Gas Lift to Low Pressure
C-5-
C-7-
C-9-
C-ll
C12-
C13-
C18-
0-30
0-7-
0110
Total (Average)
Combined Total
-P-RO
-D-RO
-D-RO
-0-RO
-0-«D
_
-
-
-
D16RB

(Average)
TVD
7T
Separator
13.995
Separator
12.247
13.024
12.765
12.988
13.125
11.533
12.6*5
12.476
13,000
12.699
11.889
.
12.630
12.629
12.658
_
-
-
Separator
12.477
13.056
13,335
13.003
13,653
-
-
-
-
13.377
-

Gas
McTd

1.650

240
382
496
501
1.001
332
988
305
170
80
235
40
253
2.456
286
307
8.072
9.722

379*
635
328
648
230
72
1.450
162*
145*
74*
3,363
13,085
Oil
Epd~

0

160
567
880
900
1.560
138
1.578
629
108
98
310
8
375
535
834
239
8.919
8.919

199*
1.011
372
670
175
60
750
82*
135*
46*
3.038
11,957
Water
"BpT"

792

0
141
0
0
0
0
0
0
0
226
724
0
0
11
0
7
1.109
1.901

465*
543
372
446
676
540
48
734*
1,209*
182*
2.625
4,526
Lift gas
Mcfd

0

0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
-
-

585
620
300
300
557
250
500
140
493
275
-
-
Pressure, pslg
SIBHP TtV

4.800

900
1.225
210
330
360
2.200
350
385
425
360
600
200
_
686
500
262
-
-

360
300
250
300
230
215
800
350
450
.
-
-
Choke size
1/64 in.

13.0

13.0
16.0
44.0
34.0
44.0
9.0
44.0
26.0
12.0
23.0
24.0
22.0
18.0
36.0
26.0
26.0
-
-

30.0
44.0
42.0
44.0
44.0
34.0
28.0
28.0
34.0
44.0
-
-
API gravity

-

35.0
34.0
32.0
34.0
38.0
38.0
40.0
38.0
37.8
31.9
31.0
33.0
34.0
36.0
30.0
36.0
(34.9)
-

27.3
35.0
37.0
37.0
35.0
31.0
36.0
27.0
-
32.0
(33.0)
(34.2)
Days of
production

All

All
All
All
Ml
All
All
All
All
All
All
All
All
All
All
All
All



9.10
All
All
All
All
All
All
9.10
9.10
9.10
-
-
•Not included In average or total.
-------
(1,000 bpd) when both wells were flowing.

Pressure Drops Through System

     Flowing tubing pressures were obtained from well  test records.  The
pressure of major vessels was recorded twice per day.   Pressure drops in the
system are reported in Table 79.  The data are recorded to permit examining
the theory that the turbulence occurring with the pressure drops at chokes
and valves may form small particle dispersions that are difficult to remove
in the separation equipment.

                TABLE 79.   BM2C  PRESSURE  DROPS THROUGH  SYSTEM

Location
High Pressure
Well, Flowing
Tubing Pressure
Pressure,
kPag
(psig)
33,072
(4,800)
Pressure drop,
point or description
chokes,
valves,
pipes
Pressure drop,
kPag
(psig)
20,350-20,640
(2,951-2,994)
High Pressure
Separator
12,450-12,750
(1,806-1,849)
control  valves,
pipes
11,900-12,240
(1,726-1,775)
                                 (1)
Low Pressure
Wells, Flowing
Tubing Pressure

Low Pressure
Separator

CPI Separator

1,380-15,170
(200-2,200)


510-550
(74-80)

0
(0)

chokes,
valves,
pipes

control valves,
pipes



830-14,660
(120-2,126)


510-550
(74-80)



(1)  Between high-pressure separator and low-pressure separator.


Chemical Addition

     Two chemicals were added continuously by small  metering pumps as listed
in Table 80.

     The rate of chemical addition was measured twice per day and was excep-
tionally uniform.  The maximum rate variation was 2 dm3/day from the averages
in the table for both chemicals.
                                     148
-------
                      TABLE 80.   BM2C CHEMICAL ADDITION
                                   Addition                Addition rate
Chemical                            point                  dm3/dppmv

Tretolite RP-34                  Low pressure                15      is' '
(Demulsifier)                    separator inlet
                                 manifold

Tretolite FR-87                  Flotation                   17      1
(Flotation aid)                  unit inlet


(1)  Based on average total water flow at the addition point.
(2)  Based on average volume of water discharged from the flotation unit.


Observations and Operator Reports

     Any occurrences observed by the survey team or reported by the operator
were recorded for possible correlation with effluent brine oil  content.

     Most of the variations from routine continuous operation occurred on the
first day.  Four gas-lift wells were produced only part of the first day and
again the ninth and tenth days.  As discussed earlier, one of the compressors
supplying the lift gas was down for repair.

     From 0700 to 1300 on the first day, the produced brine flowed through
two CPI separators in parallel.  For the remainder of the survey period the
flow was all through one CPI.

     A sample tap was not installed on the flotation unit inlet until  1000
on the first day.  A short shut in of the flotation unit to install  the
sample tap prevented taking the 1000 samples.

     The flow monitor was not fully operational  until  the middle of the
second day because of various orifice plate changes.

     On Days 5, 6, and 7, two wells from another platform flowed intermit-
tently to the BM2C system.  The water production from these wells may  have
been over 159 m3/d for short periods of time of  unknown duration.

     Production was stopped completely on Day 7  at 1500 after the 1500 sample
was taken.  The shutdown was automatic, caused by a high level  in the  flo-
tation unit.  Production was restored in about one-half hour with no apparent
effect on the test program.

     There was no rainfall drainage during the survey.

     Biocides were not used during the survey.
                                     149
-------
     In general, operations were uniform with respect to factors that would
be expected to influence effluent oil content.

DATA PRESENTATION AND EVALUATION

     Comprehensive data tables for BM2C, summary tables and graphs are inter-
spersed in the text.

Effluent Oil Content

     Table 77 presents a listing of oil content test results for the major
sampling points.  Figure 45 presents a plot of GR-Oil in and out of the
flotation unit versus time for the ten-day period.  Figure 46 presents the
same plot for IR-Oil content.  The time-indexed plots are based on four test
results per day, except for the plot of flotation unit influent GR-Oil which
is based on one test result per day.

     The tabulated data and time-indexed plots show that the oil content is
relatively consistent from sample to sample.  The ranges of test results are
as follows:
Flotation Effluent GR-Oil
Flotation Effluent IR-Oil
Flotation Influent GR-Oil
Flotation Influent IR-Oil
- 12 to 52 mg/1 ,
- 33 to 50 mg/1 ,
- 57 to 174 mg/1
- 75 to 286 mg/1
     Flotation unit effluent oil  content histograms for the two test methods
are presented in Figure 47 and Figure 48.  Figure 49 is a regression plot
of effluent GR-Oil versus IR-Oil.  In comparing oil content test results by
the two methods, it should be remembered that the samples were taken about
one minute apart from a flowing stream.  Therefore, the comparisons include
time-dependent sample differences as well as normal sampling and testing
variations.

     Table 81 presents a summary comparison of test results by the two
methods.

     The data presented in Table 81 and the histograms indicate that the mean
oil content is higher by the IR-Oil test method than by the GR-Oil test
method.  However, the scatter of the data in the regression plot, Figure 49,
indicates significant random differences can be expected in paired tests by
the two methods.  The standard deviation of 7.0 mg/1 for differences in pair-
ed tests indicates there is significant variation in the differences.

     All test results for dispersed oil and soluble oil as measured by the
IR-Oil w/Silica Gel test are listed in Table 77.  A summary of these test
results is presented in Table 82.

     On average, 87.5 percent of the oil in the effluent was soluble oil and
12.5 percent was dispersed oil.
                                     150
-------
en
             300-
             20O-
      OR-OIL
      mg/ I
             100-
             aoo-
            200-
      IR-OIL
      mg/l
             IOO-
 I
DAY
1    T    f
                                                                                                     10
                           Figure 45.  BM2C flotation unit performance, GR-oil  vs time.
                     .    '    2    '    3   '    4    '    5    '    6   '    7   '    8
                                                            DAY
                           Figure 46.  BM2C flotation unit performance, IR-oil vs time.
                                          10
-------
             90
             40
FREQUENCY
   %
             20
              10
                                                      $=67
                                                     I
                0        10        20        30       40        50
                       GRAVIMETRIC OIL CONCENTRATION , mq/ \
         Figure 47.   BM2C flotation unit effluent, GR-oil  histogram.
                         INFRARED  OIL CONCENTRATION,  mg/l
          Figure 48.  BM2C flotation unit effluent,  IR-oil histogram.

00

90
40
FR83UENCT
%
20
10
o
I 1 1
••»
NMMM»
M»
mm
•V
MHMM
MM
tm
mm
MMM
•M
mm
—
= 1 I
o 10 20 :
1 I :
n=38 I
3 = 4.2 ;








-



—
__
1 -
SO 40 90
                                    152
-------
                 90
                 40
_«      OR-OIL
co      mg/|
                 20
                  10
                                            ]i   n  r~|  i  i  r~i  p
                            GR-OIL'6f 0.4(IR-OIL)
                             r=0.25
                      I  I
I  I  I  I  I  I   I  I  I  I   I  I  i  I  I  I  I  I
                                                      "I  |   I  T~1  j   I  |   I  T
                         J  I   I  I   »  I   I  I   I
                               10
                20
3O          40
IR-OIL,  mg/l
50
60
                    Figure  49.   BM2C flotation unit effluent,  infrared gravimetric regression.
-------
                   TABLE 81.   BM2C FLOTATION UNIT EFFLUENT
                        GR-OIL AND IR-OIL COMPARISON

Oil content

Number of tests, (n)
Mean, (x), mg/1
Minimum, mg/1
Maximum, mg/1
Standard Deviation, (s), mg/1

Number, (n)
Mean of Differences, (A), mg/1
Standard Deviation, (s.), mg/1
GR-Oil
35
22
12
52
6.7
Paired
34
17
7
IR-Oil
38
39
33
50
4.2
tests

.6
.0

                     TABLE 82.  BM2C SOLUBLE OIL SUMMARY



Analysis or test
IR-Oil
Dispersed Oil
Soluble Oil
Flotation
Range
mg/1
35-50
0-17
26-42
effluent
Mean
mg/1
40
5
35
Proportion
of total ,
percent
100
12.5
87.5

Note:  Table includes only IR-Oil tests when an IR-Oil w/Silica Gel test was
       run.

     Linear regression plots of dispersed oil versus IR-Oil and GR-Oil are
presented in Figure 50.  Extrapolation of the linear regression lines to
zero dispersed oil indicates a residual IR-Oil if 38 mg/1 and a residual
GR-Oil of 21 mg/1 would still be present in the brine after all dispersed
oil is removed.

     The mean soluble oil content of the gravity separator influent was 133
mg/1, or significantly higher than the mean for the flotation effluent of
35 mg/1.

Surface Tension

     All surface tension test results are reported in Table 77.  The mean
surface tension of the CPI influent is 52 dynes/cm and the mean for the flo-
tation effluent is 60 dynes/cm.
                                      154
-------
       70-
       60-
       50-
TOTAL
 OIL
 mg/l
       40-
       30-
       20-
       10-
        0-1
I    I
                   1    I
I    I    I    1    I   I   I    I
               i   T
          • TOTAL  IR OIL VS DISPERSED IR OIL
          TOTAL  IR OIL » 38+0.44 ( J)iSRERSED IR OIL)
          r«0.6l

          • TOTAL SR OIL VS DISPERSED IR OIL
          TOTAL  3R OIL = 25+0.24 ( DISPERSED IR OIL)
          r »0.36
           \
           0
    I    1    I   I
I
5
I    I    I

 OISPCKSEO
   I
  10
IROIL,.
lilt
I   I   T
19
                 Fiqure  50.   BM2C flotation unit  effluent,
                   total  oil - disnersed oil regression.
                                       155
-------
     Eight of the ten flotation effluent surface tension test results were in
the range of 57 to 64 dynes/cm.  The other two results were 45 and 70 dynes/
cm.  The linear regression equation for effluent IR-Oil and surface tension
is:

                IR-Oil = 65 - 0.4 (Surface Tension)
                     r = -0.5

     A decrease in IR-Oil of 0.4 mg/1 is indicated for each one dyne/cm in-
crease in surface tension.

     The lowest surface tension measurement of 45 dynes/cm corresponded with
the highest effluent IR-Oil measurement of 50 mg/1.  The highest surface
tension measurement of 70 dynes/cm corresponded with an IR-Oil measurement of
37 mg/1, 2 mg/1 below the mean IR-Oil content.

     The one lowest surface tension value was most significant in establish-
ing the slope of the linear regression line.

Suspended Solids

     Suspended solids test data are presented in Table 83 for major sampling
points.  Total suspended solids and Freon soluble suspended solids data were
not obtained because of problems in completing the analyses.

     A suspended solids summary for BM2C is presented in Table 84.

     The data in Table 84 indicate that most of solids in the effluent were
acid soluble.  Both Freon insoluble and acid soluble solids increased through
the system.

     The effluent brine of BM2C had a yellowish-brown color which disappeared
on acidification.  The source of the color may have been oxidized iron com-
pounds.

     Figure 51 presents time-indexed plots of Freon insoluble suspended
solids in the flotation unit influent and effluent, and of flotation effluent
dispersed oil.  All samples were taken at the same time, 0800 each day.  The
plotted data do not demonstrate a distinct pattern that the dispersed oil
content of the effluent is higher when suspended solids are higher in the
flotation unit influent or effluent.

     As discussed in Section 18, the suspended solids test may not have
adequate precision to provide meaningful results at the concentrations pre-
sent in BM2C brine.

Filtered Brine

     The filtered brine IR-Oil content of BM2C effluent was in the range of
22 to 71 mg/1 with a mean of 51 mg/1.  The mean IR-Oil content of unfiltered
brine on BM2C was 40 mg/1 for samples when filtered brine tests were also
run.

                                     156
-------
                                     TABLE 83.  BM2C SUSPENDED SOLIDS TESTS
cn

Sample tine
Day Hour
01 08
02 08
03 08
04 08
05 08
06 08
07 08
08 08
09 08
10 08
Minimum
Haxinun
Gravity
Freon
Total soluble
.
.
.
_
.
.
-
-
-
-
' „
-
separator.
Freon
insoluble
mg/1
8
18
62
9
10
IS
16
10
9
28
6
62
in(B--i)
Acid
soluble
»9/l
7
IS
IS
9
8
IS
16
6
0
26
0
26


Fixed
mgTT
l
3
47
0
2
0
0
4
9
2
0
47


Total
ig/T
.
.
.
.
.
.
-
-
.
-
„
-
Flotation
Freon
soluble
mg/1 '

_
_
.
.
.
_
-
.
-
_
-
unit, in
Freon
Insoluble
.
8
19
11
0
12
72
7
8
220
0
220
(9--1)
Acid
soluble
.
8
14
11
0
12
72
7
0
179
0
179
Flotation unit, out

Fixed Total
mgTT igTT
.
0
5
0
0
0
0
0
8
41
0
41
Freon
soluble
mg/1
.
_
.
.
.
-
.
.
_
-
_
-
Freon
insoluble
"9/1
28
21
23
26
25
20
8
S
71
192
5
192
(9-0)
Acid
soluble
28
21
23
26
25
20
a
5
71
153
5
153


Fixed
mgTT
0
0
0
0
0
0
0
10
0
39
0
39
-------
                  TABLE  84.   BM2C  SUSPENDED  SOLIDS  SUMMARY
                                        Average suspended solids, mg/1
Suspended Solids                        8--i        9—i          9--0
Freon Insoluble
Acid Soluble
Fixed
18
12
7
40
34
7
42
38
5

Note:  Numbers do not check exactly because of rounding.

     The fact that the measured oil content of filtered brine was consistently
higher than that for unfiltered brine indicates a bias to the high side for
the filtered brine tests run on BM2C.

Flotation Unit Performance

     Figure 52 is a regression plot of IR-Oil in and out of the flotation
unit.  Figure 53 presents a regression plot of flotation unit effluent
IR-Oil content and percent hydraulic loading.  Figure 53 also presents a
similar plot for gravity separator effluent.

     Flotation effluent IR-Oil content is essentially independent of influent
IR-Oil content.  The slope of the linear regression line was only 0.008.
Flotation effluent IR-Oil content was also essentially independent of
hydraulic loading.  The slope of the linear regression line was -0.02.  In-
fluent IR-Oil was in the range of 75 to 286 mg/1.  Hydraulic loading
was in the range of 18 to 39 percent of the design capacity.

Gravity Separator Performance

     The sample point for the gravity separator  (CPI) effluent is the same as
for the flotation unit influent (9--i).

     The CPI influent (8—i) and effluent (9—i) oil content test data are
presented in Table 77.  The effluent IR-Oil content was in the range from
75 to 286 mg/1 and the mean was 158 mg/1.

      Figure  53 presents a plot of CPI effluent IR-Oil content and percent
hydraulic loading.  The design loading rate  used was 1,908 m3/d based on
removing 40-um oil drops.  Actual loading was in the range758 to 1,989 m3/d,
or 40 to 104 percent of design loading.  Within  this range, there is no
apparent correlation between  percent hydraulic loading and CPI effluent
IR-Oil content.  The calculated regression line  actually has a negative slope.

     The results of three susceptibility to separation test runs are pre-
sented in Table 85.  The mean IR-Oil content for the three runs of 161 mg/1
after one hour of settling is a little higher than the mean of 158 mg/1 for
thirty-eight CPI effluent tests.

                                     158
-------
150-
                                                                                 INFLUENT SIS."
cn
10
       O

       h
       o

       O
       o
            50-
             0-
                                   EFFLUENT DISPERSED OIL-
                                                                                                   EFFLUENT

                                                                                                   DISPERSED

                                                                                                   OIL
                                   '
                                                             \
                              *     '    '    '    4    '     §   oiy   *    '     T


                          Figure 51.  BM2C flotation unit Freon insoluble suspended  solids.
r    t    '    ,o
-------
       100-
        90-
        80-
        70-
        60-1



FLOTATION  -


 UNIT   so.


EFFLUENT


 IR-OIL
        30-
        20-
        10-
              l   I
                                T   I   I   I   I   I   I   I   I   I   I   I  I   I   I   T
                        IR-OIL out < 38* 0.008  (IR-OIL In)

                               r = O.IZ
                                                                             -•	•
                                                                                              I  .
 I   I   I
20    40
j
60
80
                   100    120   140    160    180   200    220   240    2



                   FLOTATION UNIT INFLUENT  IR-OIL, mg/1



Figure  52.   BM2C  flotation unit in-out  IR-oil regression.
                                                                                                      280    300
-------
          IR-OIL
          mg/l
CT>
                                 1   I  '   I   '   I   '  I   I   I
                          250
                          200
ISO
                          100
                           90
                                            _  t  .
                                    I.I.I
                                          (• '   I  '   |   '   I  '   |   '   I   '

                                                 GRAVITY SEPARATOR EFFLUENT
                                                                          IR-OIL'
                                                                             270- 1.6(HYDRAULIC LOADING)

                                                                             r »  - 0.30
                                                                FLOTATION UNIT EFFLUENT
                              IR -OIL- 40-0.02 (HYDRAULIC LOADING)

                                      r»-0.30


                             I   .  I  ill   I   i   I   I   i_|   I
                                         20
                            40           60           80
                               HYDRAULIC  LOADING, %
100
                           Figure 53.   BM2C hydraulic loading - infrared  oil  regression
-------
              TABLE 85.  BM2C SUSCEPTIBILITY TO SEPARATION TESTS ON GRAVITY SEPARATOR INFLUENT
ro

Test Number 1
Day 5, 1000
IR-011, mg/1
IR-011 W/Sllica Gel, mg/1
Test Number 2
Day 7, 1300
IR-Oil, mg/1
IR-011 W/Silica Gel, mg/1
Test Number 3
Day 8, 1300
IR-Oil, mg/1
IR-Oil W/Silica Gel, mg/1
Average
IR-Oil, mg/1
IR-Oil W/Silica Gel, mg/1

0
164
0
538
479
487
370

396
283
Settling time, minutes
2 5 15 30 60
130 168 366 130 105
0
378 261 261 244 168
202 -
336 227 202 235 210
126 -

281 219 276 203 161
109

120
105
0
160
101
118
. 42

128
48

0
168
521
445

378
-------
     The data for Test Number 1 in Table 85 show significant differences in
the oil separation rate of the gravity separator influent brine samples even
over the span of the few minutes required to take the samples.  Separation
rate also varies from day to day.

     The largest oil drop detected by the particle size test in the CPI
effluent had a diameter of 35 ym.

     At the time of the particle size test, the CPI separator was performing
within the assumed design objective of removing 40- ym drops.  The mean
IR-Oil content of the CPI effluent was 158 mg/1 even though the particle
size measurements indicated removal of all drops larger than 35 ym.

Miscellaneous Brine Tests

     All other brine test results for BM2C are listed in Tables 86, 87, 88,
and 89.  The results for the following tests were in narrow ranges for all
samples:  temperature, pH, and specific gravity.  These parameters were
therefore not examined for correlation for sample-to-sample variation in
effluent oil content on BM2C.  These parameters will be discussed in  with
respect to variations between platforms in Section 17.

     Only one ionic analysis test and one sulfate reducing bacteria test per
sample point were run on BM2C.  These tests also are only significant with
respect to comparisons between platforms.

Crude Oil Tests

     All crude oil test results are listed in Tables 90 and 91.  The crude
oil temperature, specific gravity, and surface tension test results all fell
in narrow ranges.

     The viscosity and boiling range distribution tests were limited in
number to one or two and are of primary significance for comparisons between
platforms.

     Two equilibration tests were run, each at a different oil/water ratio.

     The limited number of tests run on crude oil provide only a limited
characterization of the crude oil.  Between-platform comparisons will  be
presented in Section 17.
                                     163
-------
              TABLE  86.  BM2C SUPPLEMENTARY BRINE TESTS
Sample
Day
01
02
03
04
05
06
07
08
09
10
Mean
Minimum
Maximum
time
Hour
08
08
08
08
08
08
08
08
08
08



Temperature, °C pH
8—1
43.0
44.0
45.0
46.0
48.0
45.0
47.0
47.5
47.0
45.5
45.8
43.0
48.0
9—1
42.0
45.0
43.5
48.5
46.0
45.5
45.5
48.5
46.0
45.5
45.6
42.0
48.5
9—0
39.5
44.0
43.0
47.0
47.0
45.5
46.5
47.0
46.5
44.5
45.0
39.5
47.0
9—0
7.1
6.7
6.5
6.4
6.5
6.6
6.5
6.6
6.7
6.5
6.6
6.4
7.1
Specific(lj
grav i ty
9—0
1.090
1.093
1.094
1.089
1.092
1.095
1.093
1.095
1.095
1.098
1.093
1.089
1.098

Note:   Sample  point  identification numbers (8—i,  9—i,  9—0)  as
       shown on  flow diagrams.

(1)    Specific  gravity is reported at temperature shown in  table
       above.
         TABLE  87.   BM2C BRINE TESTS AT MINOR SAMPLING POINTS

Sampje
Day
03
06
time
Hour
08
08
IR-Oil,
5A20
1,030
303
mg/1
6—0
240
84
Temperature, °C
5A20 6—0
46.0 42.0
45.5 44.5
 Note:  5A20 is the low pressure separator  effluent.
       6—0 is the oil treater effluent.
                                 164
-------
             TABLE 88.  BM2C SULFATE REDUCING BACTERIA
Sample time
Bacteria per miTh'liter
Low Pressure Separator - Out
Gravity Separator (CPI) - In
Gravity Separator (CPI) - Bottom
Flotation Unit - In
Flotation Unit - Out

Sample Day and Hour:  06 at 16
          0
       100-1,000
     1,000-10,000
          0
        10-100
       TABLE  89.   BM2C  IONIC ANALYSIS  FLOTATION UNIT  EFFLUENT
Constituent
       Concentration, mg/1
Sodium  (Na)
Potassium  (K)
Calcium (Ca)
Magnesium  (Mg)
Barium  (Ba)
Chloride (Cl)
Sulfate (S04)
Alkalinity   (as HC03)
Iron  (Total)
Sulfide (as  H2S)

Total Dissolved Solids
      Summation
      Gravimetric

Sample  Day and Hour:  09 at  15
             42,000
                405
              1,750
                360
                 79
             60,800
                  6
                555
                  5
                  0.10
            105,000
            114,000
                                165
-------
            TABLE 90.  BM2C CRUDE OIL MISCELLANEOUS TESTS
                                                         (1)

Sample time
Day Hour
01 08
02 08
03 08
04 08
05 08
06 08
07 08
08 08
09 08
10 08
Mean
Minimum
Maximum
Temperature
°C
32.5
37.5
37.5
40.5
42.0
40.5
40.5
41.5
40.0
38.5
39.1
32.5
42.0
Specific(2)
gravity
0.835
0.836
0.830
0.828
0.827
0.830
0.829
0.831
0.831
0.832
0.831
0.827
0.836
Surface tension^)
dynes /cm
26
25
25
23
24
24
22
29
24
25
25
22
29
Sample time
Day    Hour
09
15
                   Viscosity at 37.77*C
                 KinematicAbsolute
                centistokes     centipoise
4.02
3.41
                          Equilibration at 82°C
                       Brine TDS »  105,000 mq/1
Oil/Water  Ratio              4/1
IR-011, mg/1                  8
IR-Oil W/Silica  Gel, mg/1     5
IR-Oil Filtered  Brine,  mg/1   3
                                   2.64/1
                                    8
                                    6
                                    6
 (1)  Samples taken  from oil treater.
 (2)  Specific gravity reported for temperature in table.
 (3)  Surface tension measured and reported at ambient temperatures
     from 21.2°C to 25°C.
                                   166
-------
            TABLE 91.  BM2C CRUDE OIL BOILING RANGE DISTRIBUTION
                                           Run
Initial Boiling Point, °C                  150
Final Boiling Point, °C                    410
Boiling range, °C                   Percent recovered

Below - 200                                61.1
  200 - 250                                22.6
  250 - 300                                13.2
  300 - 350                                 2.4
  350 - 400                                 0.6
  400 - 450                                 0.1
  450 - 500                                 0.0

Total                                     100.00
                                     167
-------
                                 SECTION 10

                              PLATFORM ST131
GENERAL
     The ten-day test program was conducted on Platform ST131 from March 16
through March 25, 1980.  The operating company provided the transportation,
accommodations, utilities, and operational information needed for a success-
ful survey.

     The test equipment was transferred by boat to Platform ST131 directly
from Platform BM2C.  High waves caused a one-day delay in unloading the
equipment.

     There were minor variations in production and water treating parameters
during the survey period.  However, the variations were not of a nature to
cause a single planned sample to be lost.

FACILITIES AND OPERATIONS

Production From Wells

     Sixteen wells were in production for at least one day during the survey
period.  Twelve wells produced continuously and the others intermittently.

     Two wells flowed to the high-pressure separator.   Ten wells flowed to
the low-pressure separator.  The other four wells were gas lifted'to the
low-pressure separator.

     The estimated production based on well test data is 295 m3/d (1,853 bpd)
of oil, 138 m3/d (870 bpd) of water, and 215,700 std m3/d (7,623 Mcfd) of gas
for wells producing on at least five days.  The calculated water cut is 32
percent.  The water cut varied significantly from day to day because one well
producing more than half of the water flowed intermittently.

     Sixty-four percent of the oil  was gas lifted, and twenty-one percent of
the water was gas lifted.

Production Process System

     Figure 54 is a flow diagram of the ST131 production process system.
Design and operating data on major  vessels are presented in Table 92.   Two
wells flow to the high-pressure two-phase separator and all  liquids then flow


                                      168
-------
WELLS
HP



C •» )
WELLS
LP
( 1C }
WELLS
LP



QD
1

!„




CHOKES
VALVES




CHOKES
VALVES
QD
CHOKES
VALVES
.(
V




( 4B 3
l



HP SEP
a/L

1
(


1 f^~^


( IT )
A
)
v$y
I /
k *i


•
r


                                                                               GAS
VO
        LEGEND




    C  _")  UNIT OESI6NATIOM




          SAMPLE POINI




    	INTEMMITTENT  FLOW
                                                                                                                         OIL
                            Figure  54.  Flow diagram,  production process  system,  ST131.
-------
-4
CD
^ f li.H-.i-. -^*- • 	 y '. * ^ * • jff"^ **T- t * f f A- -Tf* 'T-l-t 1 	 	 . 	 	 	 	 • •• i" ' • ••'•' " -' ~" " 	
VESSEL DESIGNATION ON FLOW DIAGRAM - FIGURE (0-1
SA1 5A2 8 9
High pressure Low pressure Gravity Flotation unit,
2 -phase 3-phase separator, Mechanical,
Vessel description separator separator gun barret dispersed gas
Trade Name or Vessel Type Horizontal Horizontal Rectangular Wemco
Cylinder Cylinder
Design Parameters
Dimensions, a. (ft)
Diameter. O.D. - 1.8(6)
Length, S.S. - 6.1(20)
Length 6
Width 4
Height 6
Separation Surface Area, «2,(ft2)
Total - 29
Per Cell - -
Separation Volume, n . (bbl)
Total - - 170
Oil Phase - - 54
Water Phase - - 116
Number of Cells ...
Flow Rate, «3/day.(bpd)(2^
Overflow Rate Per Cell, («3/d)/»2,(bpd/ftV3) - ...
Recycle Rate. Percent of Flow
Retention Time. mln.
Average Operating Parameters
Temperature, °C(°F) - 22.9(73} 22.
Pressure. kPag(pstg) 6.757(980) 517(75) 0
Model 56


.
i\\
86(22.5) 5.70(18.7)),.'
27 14) 1.31 4.3)
15(20.2) 0.85(2.8) t»)

3(315) 7.43(80)
1.86(29)

1,070) 4.55(28.6)
340)
730)
4
1,638(10.300)
881(515)
-
4

8(73) 22.6(73)
0
Flow Rate. »3/d,(bpd)t2) - - 241(1.516) 111(698)
Flow Rate, Percent of Design ...
Overflow Rate Par Cell, (n3/d)/»2.(bpd/ft2) f2) - - 8.
Recycle Rate, Percent of Flow ...
Froth Flow, Percent of Flow(2)
7
2(4.8) 60(35)
_
117
                      ll\  Separation tank only.
                           Based on effluent flow.
                      (3)  Overflow rate is surface area divided by  flow rate.
-------
to the low-pressure three-phase separator.

     All other wells flow, or are lifted, to the low-pressure separator.  Oil
flows from the low-pressure separator to a storage tank and brine flows to
the gun barrel.  The brine flows from the gun barrel to the flotation unit
and then to discharge.

     Miscellaneous drains are connected to sumps from which the fluids
received are pumped back to the gun barrel.  During the survey the only
significant flow to sumps was the flotation unit skimmings.  Minor flows to
sumps occurred from washdown of curbed areas.

     A flotation aid, Tretolite FR-81, was added to the influent of the
flotation unit.

     Figure 55 is a flow schematic for the water streams to and from the
gun barrel and the flotation unit.  The flow rate of the produced brine was
monitored at the gun barrel inlet.  The flotation unit skimmings flow was
estimated based on time and rate of pumping of the sump pump.  Flow rates at
other points were calculated.

     A nominal average water flow balance is presented in Figure 55.  The
flow rate of the flotation effluent and skimmings at each sampling time is
presented later in this section.

     The gun barrel receives oily water and provides for gravity separation
of oil to prepare the water for flotation.  The gun barrel on ST131 is
identical to the one on ST177.  A dimensional sketch of the ST177 gun barrel
is presented in Section 8 in Figure 31.

     Based on the average flow from the gun barrel of 241 m3/d the average
residence time in the gun barrel is calculated to be 12 hours.  This is a
very conservative residence time for a gravity separator.  However, the pro-
duced brine portion of the flow is discharged through a distributor near the
bottom of the tank.  There is significant potential for short-circuiting to
the outlet which is also near the bottom.  There is no simple way to estimate
actual residence time or separation capability of the ST131 gun barrel.

     The flotation unit (Wemco 1+1, Model 56) on ST131 is the same type as
the one on SP658, a four-cell unit with mechanical gas dispersion.  This type
unit was described in Section 6 and depicted in Figure 6.

     The design flow for the ST131 flotation unit is 1,638 m3/d (10,300 bpd).
The average operating flow was 111 m3/d (698 bpd) or 7 percent of design flow.
The skimmings flow was 130 m3/d (818 bpd), or 117 percent of the effluent
flow.

SITE SPECIFIC TEST PROGRAM

     The planned sampling and testing schedule for ST131 brine tests is  pre-
sented in Table 93.  The sample point, number of samples in ten days, and
the time of day for each sample are listed.

                                     171
-------
SUMP
                               GUN BARREL
FLOTATION  UNIT
FROM    |
 LP 	
SEPARATOR
                                                     FLOTATION
                                                         AID
                                                                                 c *-
                                                                                          TO
                                                                                          SEA
WATER
FLOW m 3/d
bpd

5A20
III

698
14-0
130

818
9F
130

818
8...
Ill

698
9 	 1
241

1516
9 	 0
III

698
                 Figure 55.  ST131 water handling system flow schematic
-------

L.P.
SEPARATOR
G/O/W

SUMP
\
> ^*x.
w


GRAVITY
SEPARATOR
„


FLOTATION
UNIT
Y

                          TABLE  93.   ST131 TEST  SCHEDULE  FOR THE  MAJOR  BRINE TESTS
  IR-Oil U/Silica Gel
  IR-Oil Filtered Brine
  Susceptibility to Separation
                      (3)
laboratory Tests
  Gravimetric Oil
  Suspended Solids
  Ionic Analysis
  Bacterial Culture        ,.,
  Particle Size Distribution*  '
                                                                                  SAMPLE POINTS
9--0

Field Tests
Infrared Oil
Temperature
PH
Water Specific Gravity,,,
Uater Surface Tension* '
No. of
tests
20
10
10
10
10
Tine of
tests
8.13
8
8
8
8
9--1 8--1
No. of
tests
20
10
Tine of No. of Time of
tests tests tests
8,13 20 8.13
8 10 8
10 8
14--0
No. of
tests
2
2
Tine of
tests
8
8
                                       20
                                       20
8.13
8.13
                                                   10
                                                   10
                                                    3
 8
 8
13
                                                                 10
                                                                 10
                                            10
                                                     8
40   8.10.13.IS
10       8
 1       (1)
A naximw of five tests at sample points selected in  the field.
 3       13                 3       13                3       13
 (1
 <2(
 (3!
 (4]
Sampling times not shown will  be field scheduled.
Extra  samples when IR-OU is high.
IR-011 w/silica gel at 0. 5. and 120 minutes.
IR-Oil. IR-Oil w/sllica gel. and filtered brine tests at  same time.
                                      NOTE:   Time of tests listed  is by military hour.
-------
     In addition to the brine tests, the following tests were run on ST131
crude oil:  temperature, specific gravity, surface tension, viscosity,
equilibration, and boiling range distribution.

OPERATIONAL DATA AND OBSERVATIONS

     Measurements and observations by the survey team and reports and records
provided by the operator are presented in this subsection.

Flow Monitoring

     The produced brine flow into the gun barrel was monitored continuously
using a Doppler meter with a sensor that clamped on the outside of the pipe.
Short term flow variations over a few seconds were so wide that the strip
chart record was not readable.  However, it was possible to confirm that the
average flow estimate by well test data was reasonably accurate.  This was
done by visually reading the flow indicator on the monitor each 15 seconds
for 10 minutes and calculating an average flow.

     The flow monitor was particularly useful in detecting the intermittent
flow from high-water-producing well D-15.

     A flow rate for the flotation effluent is reported for each sampling
time in Table 94.  These flow rates are calculated by subtracting other
known flows from the monitored flow as discussed earlier.

Well Test Data

     The well test data provided by the operator are listed in Table 95.
The data are grouped according to whether the flow was to the high-pressure
separator or low-pressure separator.  The data for wells flowing to the low-
pressure separator are further subdivided according to whether the well was
flowing or was gas lifted.

Pressure Drops Through System

     The pressures of the high-pressure separator and the low-pressure
separator were recorded twice per day.  The flowing tubing pressure for each
well was obtained from well test data.  The ranges for these pressures are
presented in Table 96.  The magnitude of pressure drops between different
points in the system are also listed.

Chemical Addition

     Two chemicals were added continuously by small metering pumps at the
average rates listed in Table 97.

     The addition rate of the demulsifier was quite uniform for the ten-day
period.  Sixteen of eighteen flow measurements were from 3.3 to 3.8 dm3/d.
The other two were 4.7 dm3/d.
                                     174
-------
                                                        TABLE  94.  ST131  MAJOR BRINE TESTS
en
Gravity separator Influent (8--1)
Sample tine
Day
01
01
01
01
02
02
02
02
03
03
03
03
04
04
04
04
05
05
05
OS
06
06
06
06
07
07
07
07
08
08
08
08
09
09
09
09
10
10
10
10
Hour
08
10
13
15
08
10
13
IS
08
10
13
IS
08
10
13
IS
08
10
13
15
08
10
13
IS
08
10
13
15
08
10
13
IS
08
10
13
IS
08
10
13
15
Minima
Maximum
IR-011 M/sllica gel
IR-011 "Dispersed11
•g/1
7,891
.
2.686
.
2.728
-
2.141
.
10.284
.
20(1)
-
15(1)
_
881
«.
4.659
.
20(1)

24(1)
.
84(1)

35(1)
.
8(1)

45(1)

22(1)
.
58(1)
-
10(1)
-
227
-
130
-
130
10.284
•9/1
7.052
.
.
.
2.477
.
.
.
4.617
.
.
.
-
-
_
_
3.946
.
.
.
.
.
-
_
-
.
-
.
-
-
-
.
-
.
-
-
143
.
-
-
143
7.052
"Soluble"
•9/1
839
-
-
.
251
-
-
-
5.667
-
-
-
-
.
.
.
713
-
.
-
-
-
-
.
-
-
.
-
-
-
-
.
.
-
-
-
84
-
-
-
84
S.667
Filtered
brine Surface
IR-011 tension
•9/1
218
-
.
-
56
.
.
-
63
.
.
.
59
.
_
.
44
.
.
-
688
-
.
.
84
-
.
-
923
.
.
.
151
-
.
-
78
-
-
-
44
923
dynes/en
47
-
45
-
54
-
57
-
35
-
42
-
38
.
43
.
56
.
34
.
33
-
33
.
28
-
39
-
36
-
26
.
34
-
26
-
56
-
59
-
26
S9
Flotation unit
Influent (9-1)
GR-Otl
•9/1
175
-
.
-
259
.
.
-
479
.
.
-
245
.
_
_
444
.
.
.
170
.
.
.
173
.
.
.
159
.
.
.
312
-
.
-
82
.
_
-
82
479
IR-011
•9/1
260
.
361
-
550
.
718
-
798
-
445
-
407
.
541
.
756
-
239
-
269
-
285
.
277
.
197
-
231
.
344
-
504
-
185
-
222
.
126
-
126
798
GR-011
•9/1
11
7
6
4
50
43
34
17
13
12
10
9
14
12
3
1
4
2
57
7
20
6
5
3
11
18
IB
7
11
10
7
2
1
4
11
4
1
11
22
12
1
57
JR-011
•g/1
27
.
44
.
76
.
64
.
41
.
37
-
21
.
26
.
25
.
92
.
27
-
26
.
29
.
29
.
30
.
29
.
24
-
33
.
28
.
31
-
21
92
Flotation unit effluent (9—0)
IR-011 w/sll
Dispersed
•9/1
1
-
16
-
47
-
36
-
9
-
4
-
0
-
0
_
0
.
88(A)

0
.
0
.
0
-
0
.
0
.
0
-
0
.
0
-
0
-
0
-
0
47
lea gel
Soluble
•9/1
26
-
28
-
29
-
28
-
32
-
33
-
21
-
26
_
25
.
4(A)
.
27
.
26
.
29
.
29
-
30
.
29
_
24
.
33
.
28
.
31
-
21
33
Filtered
brine
1R-011
•9/1
39
-
49
-
44
-
56
-
41
-
44
-
36
.
40
.
12
-
40
.
40
-
46
.
42
-
66
.
54
..
64
_
44
-
47
.
42
.
50
-
12
66
Surface
tension
dynes/cm ,
47
-
-
-
47
-
.
-
S3
-
-
-
67
-
.
-
66
-
.
-
62
-
-
.
62
.
-
.
70
-
.
.
68
.
-
-
63
.
.
-
47
70
Flow rate
Out SHaalngs
90 33
90 33
190 33
190 33
181 5
1B1 153
181 153
181 153
90 142
190 142
190 142
190 142
101 147
150 142
150 142
ISO 142
188 109
80 109
80 109
80 109
82 229
82 229
82 229
82 229
82 229
82 229
82 229
82 229
82 218
82 218
82 218
82 218
82 11
82 27
82 27
82 218
55 5
55 5
55 5
55 5
55 5
190 229
!l)   Oil content reported in percent as measured by the water cut  test.
A)
                                                                        .
              Not  Included In statistical analysis.  Appears  Inconsistent with all other IR-011 w/sllica gel tests.
-------
                                               TABLE  95.  ST131 WELL TEST DATA
en
Mel) Formation
Flowing to High Pressure
C10-
0-5-
Total (Average)
Flowing to low
C-90
CIS-
C' 2-
1-2-
J-2D
J-3-
J-40
J-B-
J14-
J14D
Total (Average)
Flowing Total
E-2C
C-7G

Pressure
E-GA
0-5E
C-3K
E-9N
C-7C
DUE
C-3F
C-31
OlOf
0-3F


Gas lift to tow Pressure
C-3-
C-70
0-7-
J-9-
Total (Average)
Combined Total
E-9A
0-3G
D-20
E-2A

(Average)
TVO
7f
Separator
9.795
6.870

Separator
10.170
7.342
S.730
8, 660
6. 975
7.005
6.480
6.780
7.835
7,370
-
-
Separator
10.600
7.465
-
8.375
-
-
Gas
ficTd"

900
1.400
2.300

165
.
1.900 .
64
1.000*
620*
340
1.995
90
250
4.804
7,104

200
19
60
240
519
7.623
Ep3

24
11
35

159
0
18
95
0*
0*
90
0
46
221
629
664

395
47
148
599
1,189
1,853
Water
TpF

0
2
2

159
450
0
11
0*
0*
0
0
68
0
688
690

0
31
0
149
180
870
lift gas
Hcf3

0
0
-

0
0
0
0
0*
0*
0
0
0
0
-
-

950
821
780
620
3.171
-
Pressure, psig
S1BHP

3.084
1.950
-

3,645
2.697
2.496
3,822
1.472
1.932
2,191
1.997
3,473
-
-
-

2.413
1,764
3,120
2.233

-
FTP

2,100
1.800


300
•
1.880
320
1.075
550
850
1.500
250
950
-
-

225
240
225
290

-
Choice size
1/64 In.

9
12


17
-
14
12
13
15
16
18
12
12
-
-

48
64
48
64

-
API gravity

50.5
-
(50.5)

32.9
-
.
34.9
-
-
34.1
-
37.5
38.7
(35.6)
(38.1)

34.6
29.4
36.7
37.6
(34.6)
(36.7)
Days of
production

All
All


All
1,2.3.4.6
All
1-8.10
1
1
All
AM
All
All



All
All
All
All


          * Hot included in average or total,
-------
                TABLE 96.   ST131 PRESSURE DROPS THROUGH SYSTEM
Location
 Pressure,
   kPag
  (psig)
                       Pressure drop,
   Pressure drop,          kPag
point or description      (psig)
Flowing Tubing     1,550-12,960
Pressure            (225-1,880)
High Pressure
Low Pressure
Separator
Gun Barrel
6,380-6,890
 (925-1,000)
  480-590
  (70-85)
     0
     0
                        chokes,
                        valves,
                        pipes
     control valve,
     pipes


     control valve,
     pipes
                        960-12,480
                       (140-1,810)(1)
                                                            5,790-6,410
                                                             (840-930)
480-590
(70-85)
(1)  Minimum and maximum pressure drops are to the low-pressure separator.
     Does not include well C-;10 flowing to the high-pressure separator.
                      TABLE 97.  ST131 CHEMICAL ADDITION

Chemical
Tretolite RP-101
(Demulsifier)
Tretolite FR-81
(Flotation aid)
Addition
point
Low pressure
well manifold
Flotation
unit inlet
Addition
dm3/d
3.8
14
rate
pprmr
34
126
1)



(1)   Based on average produced brine flow of 111 m3/d.

     The addition rate of the flotation aid chemical was also relatively
uniform.  Nineteen of twenty-four measurements were between 10 and 17 dm3/d.
The afternoon of the tenth day the measured rate was 7.6 dm3/day.  The flota-
tion chemical feed pump stopped pumping from 1230 to 1300 on Day 1.  It also
stopped pumping during the night of Day 1 and was restarted at 0800 on Day 2,
                                     177
-------
     A detergent, Great Southern GS-1011, is occasionally used to wash down
curbed areas on ST131.

Observations and Operator Reports

     The purpose of this subsection is to describe variations in operations
or any known non-routine event that could influence effluent brine oil
content.

     Numerous changes in brine flow rate occurred because of changes in
which wells were producing.  The changes were described in the subsections
on Flow Monitoring and Well Test Data.

     Numerous changes occurred in flotation unit skimmings rate.  The skim-
mings rates for each sampling time are listed in Table 94.

     Interruptions in flotation chemical feed were described in the immedi-
ately preceding subsection.  At 0800 on Day 2, when the chemical feed was
off, it was observed that the foam in the flotation unit was a few inches
below the skimming weirs.  It is not known how long this condition existed.

     On Days 3, 4, 5, 6, 7, 8, and 9, high concentrations of oil were dis-
charged from the low-pressure separator to the gun barrel.  As listed in
Table 94, samples contained from 8 to 84 percent oil, rather than 1 percent
or less.  The reason was that the low-pressure separator was operated with
a low oil/water interface level.

     Detergent GS-1011 was used to wash curbed areas.  One wash down using
several cubic decimeters of detergent was at 0800 on Day 10.  The operator
expected a decrease in foam level in the flotation unit but this was not
observed.  Also, none of the test results appeared to be affected.

DATA PRESENTATION AND EVALUATION

     Comprehensive data tables for ST131 are interspersed in the text.

Effluent Oil Content

     Table 94 presents a listing of oil content test results for the major
points.  Figure 56 is a plot of GR-Oil in and out of the flotation unit
versus time for the ten-day period.  Figure 57 presents a similar plot for
IR-011.

     The tabulated data and the time-indexed plots show that effluent oil
content is relatively consistent from sample to sample.  However, there are
oil content peaks on Day 2 and Day 5.  The flotation chemical  feed pump
stopped during the night for an unknown period of time before the 0800
sample on Day 2 was taken.  The pump was restarted just after the sample was
taken.  No reason is known for the high oil  content measurements on Day 5
at 1300.
                                     178
-------
      aoo-
      700H
      60O-
      900-
6R-OIL 4OO-
       3OO-
      20O-
       100-
                                                      DAY
                                                                                   T	T
                                                                                                 10
                   Figure 56.  ST131 flotation unit  performance, GR-oil vs  time.
-------
00
o
             800-
              70O-
             6OO-
             5OO-1
        IR-OIL 40O-
              300-
              200-1
              IOO-
                           Figure 57.   ST131  flotation unit performance, IR-oil vs time.
-------
     The ranges of test results are as follows:

     Flotation Effluent GR-Oil - 1 to 57 mg/1,
     Flotation Effluent IR-Oil - 21 to 92 mg/1,
     Flotation Influent GR-Oil - 81 to 479 mg/1,
     Flotation Influent IR-Oil - 126 to 798 mg/1.

     Flotation unit effluent oil content histograms are presented in Figure
58 and Figure 59.  Figure 60 is a regression plot of GR-Oil versus IR-Oil.
Paired GR-Oil and IR-Oil samples were taken about one minute apart from a
flowing stream.  Therefore, the comparisons include time-dependent sample
differences as well as normal sampling and testing variations.

     Table 98 presents a summary comparison of test results by the two
methods.

     The data in Table 98 and the histograms illustrate that IR-Oil is con-
sistently higher than the GR-Oil.  However, the data in Table 98 and the
scatter in the regression plot, Figure 60, indicate that there is not a
uniform difference in paired tests by the two methods.

     All test results for dispersed oil and soluble oil as measured by the
IR-Oil w/Silica Gel test are listed in Table 94.  A summary of these test
results is presented in Table 99.

     On average, 82 percent of the oil in the effluent was soluble oil  and
18 percent was dispersed.  Thirteen of nineteen samples did not contain any
dispersed oil.

     Linear regression plots of dispersed oil  versus IR-Oil and GR-Oil  are
presented in Figure 61.  Extrapolation of the regression lines to zero dis-
persed oil indicates a residual IR-Oil of 28 mg/1 and a residual  GR-Oil of
9 mg/1 after all dispersed oil has been removed.

     The mean soluble oil content of the gravity separator influent was
1,511 mg/1 for five tests.  The range was 84 to 5,667 mg/1.  The range is
so wide and the average so high that these test results are in question as
giving an accurate indication of soluble oil  in the gravity separator
influent.

Surface Tension

     All surface tension test results are reported in Table 94.  The mean
surface tension of the gravity separator influent is 41 dynes/cm and the
mean for the flotation effluent is 61 dynes/cm.

     The flotation effluent surface tension test results were in the range
of 47 to 70 dynes/cm.  The linear regression equation for effluent IR-Oil and
surface tension is:

               IR-Oil = 107 - 1.24 (Surface Tension)
                    r = -0.65

                                     181
-------
— „
60-
50—
40-
30-
10-

1 1 1 I 1 t 1 | 1 _
**40' Z
5=13 Z
-
••MM*





—


—
—
1 — 1 -
Inn , , , -
O
z
o    _;
a:
u.
                 20
            40          60

            QR-OILt mg/l
                       80
   Figure 58.   ST131 flotation unit effluent, GR-oil  histogram.
   60-
   50-
3s 40-
 **   «•

o   2
   20-
    10—
            i      f      i     i       i     I      i     i
                                                x-37
                                         n.   n
                                         60          80
20
i      i
     40
           60

IR-OIL, mq/1
   Figure  59.   ST131  flotation  unit effluent,  IR-oil  histogram.
                               182
-------
00
CO
              6O-
              40—
              30—
       OR-OIL
        mg/l
              20—
              IO-
T — n — rn — mm — i — r~i — m — n — i
                                                                            i — r~ i — i  i  i  i   r
                    i  r
                                               GR-OIL* -ll»0.72( IR-OIL)
                                               i - 0. 89
      I
      20
 I   I
40
 i   i   i   i  i   i   i
60          80
 IR-OIL,mfl/l
 i
100
i   i
  120
                   Figure  60.   ST131  flotation  unit  effluent,  infrared-gravimetric regression.
-------
                   TABLE 98.   ST131 FLOTATION UNIT EFFLUENT
                         GR-OIL AND IR-OIL COMPARISON

Number of tests, (n)
Mean, ("x), mg/1
Minimum, mg/1
Maximum, mg/1
Standard Deviation, (s), mg/1
Number, (n)
Mean of Differences, (A), mg/1
Standard Deviation, (SA), mg/1
Oil
GR-Oil
40
12
1
57
12.8
Pai

content
IR-Oil
20
37
21
92
18.8
red tests
20
21.55
8.7
                   TABLE 99.  ST131 SOLUBLE OIL SUMMARY

Analysis or test
IR-Oil (1)
Dispersed Oil
Soluble Oil
Flotation
Range
mg/1
21-76
0-47
21-33
ef f 1 uent
Mean
mg/1
34
6
28
Proportion
of total ,
percent
100
18
82
(1)  Includes only 19 test results when IR-Oil  w/Silica Gel  tests were
     obtained on same sample.


     A decrease in IR-Oil  of 1.24 mg/1  is indicated for each 1 dyne/cm in-
crease in surface tension.

Suspended Solids

     Suspended solids test results are  listed in Table 100 for major sampling
points.  A suspended solids summary for ST131 is presented in Table 101.

     The data in Table 101 indicate a decrease  in suspended  solids through
the system with minor exceptions.  Acid soluble suspended solids apparently
increased through the gravity  separator, 8—i to 9--i.   The  reduction of
Freon soluble suspended solids in the flotation unit of 1 mg/1 is insignifi-
cant in relation to the accuracy of the test.
                                    184
-------
TOTAL
 OIL
mg/l
         140
         120
         100
          80
          60
          40
          20
T  j  i     i   ;  ir
                                           i   i  r
i  i  r
                                                 i   i  r
• TOTAL IR OIL VS DISPERSED  1R OIL
TOTAL I ROIL = 28 +1.03 (DISPERSED IR OIL)
• TOTAL GR OIL VS DISPERSED  IR OIL

TOTAL GR OIL =8.9 4-0.73( DISPERSED  IR OIL)
 r=0.8l
               D         10             20          30

                                   DISPERSED IROIL,mg/l

               Figure 61.  ST131 flotation  unit effluent,
                  total  oil  - dispersed oil  regression.
                                            40
                                    185
-------
                                              TABLE  100.   ST131 SUSPENDED SOLIDS TESTS
00
en
Sample time
Bay Hour
01 OB
02 08
03 08
04 08
05 08
06 08
07 08
08 08
09 08
10 08
Minimum
Maximum

3fr
488
573
248
(1)
72
S37
(1)
1
hi
21
21
573
Gravity
Freon
soluble
•97 •
371
330
216
(1)
41
389
m
1
(li
18
18
389
separator, in (8— J)
Freon Acid
Insoluble soluble
Mg/ I •*9/ '
117
243
32
24
36
14
(1) (1)
31
147
(1
1
(1
3
3
243
7
42
(!)
1
hi
3
3
42
Fixed
iflTT
93
208
18
(1)
23
106
(1)
1
(0
0
0
208
Total
igTT
60
60
62
73
85
52
295
53
71
24
24
295
flotation unit, in (9— i)
Freon
Ifilubje.
4
42
23
43
45
39
32
34
40
19
4
45
Freon
insoluble
56
19
39
30
40
13
263
19
31
5
5
263
Add
soluble
flit}/ 1
5
3
12
0
24
12
198
10
8
5
0
198
Fixed
igTT
51
16
27
42
17
1
64
9
23
0
0
64
Total
ig/T
9
47
6
249
15
30
25
5
11
6
5
249
Flotation <">" ""* (9"-0)
Freon
soluble
1
30
5
234
2
19
0
7
7
4
0
234
FreoA
insoluble
«9/1
a
18
2
14
13
11
25
1
4
2
1
25
AC1U
soluble
7
9
3
26
13
11
23
1
0
2
0
26
Fixed
igTT
0
8
0
0
0
0
2
0
4
0
0
8
       (1)  Filters plugged by oil before an adequate volume of water was filtered  for the test (less than 60 ml).
-------
                 TABLE 101.  ST131 SUSPENDED SOLIDS SUMMARY
                                           Average suspended solids, mg/1
Suspended Solids                           8—i        9— i          9—0
Total
Freon Soluble
Freon Insoluble
Acid Soluble
Fixed
323
228
96
21
75
84
32
52
28
25
40
31
10
10
1

     Figure 62 presents time-indexed plots of Freon insoluble suspended
solids in the flotation unit influent and effluent, and of flotation effluent
dispersed oil.  All samples were taken at the same time, 0800 each day.
The plotted data do not demonstrate a distinct pattern that the dispersed
oil content of the effluent is higher when suspended solids are higher in
the flotation unit influent or effluent.

     The Freon insoluble suspended solids content of the effluent is low, 10
mg/1.  Two tests on the same sample could differ by more than 10 mg/1  as dis-
cussed in Section 18.  This degree of variability could mask any correlation
with effluent oil content.

Filtered Brine

     The filtered brine IR-Oil content of ST131 effluent was in the range of
12 to 66 mg/1 with a mean of 45 mg/1.  The mean IR-Oil  content of unfil-
tered brine on ST131  was 37 mg/1 for samples when filtered brine tests were
also run.

     The fact that the mean oil content of filtered brine was higher than
that for unfiltered brine indicates a bias to the high side for the filtered
brine tests run on ST131.

Flotation Unit Performance

     Figure 63 is a regression plot of IR-Oil in and out of the flotation
unit.  Figure 64 is a regression plot of flotation unit effluent IR-Oil
content and percent hydraulic loading.

     Flotation effluent IR-Oil content increases gradually as influent IR-Oil
content increases.  The slope of the linear regression  line was only 0.016.
The correlation coefficient of 0.17 indicates a very limited correlation.

     The hydraulic loading of the flotation unit was in the range from 3.4
percent to 11.6 percent of the design capacity.  The plot in Figure 64 in-
dicates an increase in IR-Oil  with an increase in hydraulic loading.  However,
the maximum loading of 11.6 percent is so low that the  data are of limited

                                    187
-------
00
00
             250—
             20O-
            o>
            £
              160-
ui
o

8
              loo-
                0-
                                                               ft
                                                                  \
                                                                  \
                                                                      /
                                                                    \
                                                                     \
                                                                                  \
                                                    INFLUENT S.S.—^I


                                                      "X    '
                                                 NT S.S.-^     V  /
                                                         * — -
                                                                        \
                                                     EFFLUENT'txSPERSED" OIL
                         -]	1	
                              3        4
T	,	1^	

     5          67
         DAY
                                                                                                           10
                           Figure  62.   ST131 flotation unit Freon  insoluble suspended solids.
-------
00
to
          IOO
       -   80
       \
       o
       E
       o


       £  60
           40
       O
           20
IIIIIrr
                                     j  1  I  I  I  T
                              i  I   r
r  i  i^     i  i   I  i
ii  i    i   F
                                                                        IR-OIL out • 31 + 0.016 (IR-OfLin)

                                                                                t * 0.17
               II  I
I  I  I  I   I  I   I  I   I  I   I  I   I  I   I  I   I  t  I  t  I  I  t  l  i   i  I   I _ I   i  I   I  II  II
                        100
              200          300          400         500

              FLOTATION UNIT  INFLUENT  IR-OIL,  mfl/l
                                                                                       600
                                  700
                            Figure 63.   ST131 flotation  unit in-out  IR-oil  regression.
-------
vo
O
                   O
                   v.
                       too
                        90
                        80
                        70
                        60
                        50
til
t
z
D
O
E   4°
                        20
                        10
                          O
                                I	I
                                           _L
                                                                                        T
                                                                           T
                          T
      T
                                                           IR-OIL - 16 + 2.6 (HYDRAULIC LOADING)
                                                               r » 0.57
_L
                                            6           8
                                         HYDRAULIC LOADING . %
             10
12
                          Figure 64.   ST131  flotation unit  hydraulic loading  -  infrared oil  regression.
-------
 value  for  predicting  performance  at  higher  loadings.

 Gravity  Separator  Performance

     The sample  point for  the  gravity  separator  effluent  is  the  same  as  for
 the  flotation  unit influent  (9—i).

     Gravity separator influent (8~i)  and  effluent  (9—i) oil content test
 data are presented in Table  94.   The separator effluent IR-Oil content was
 in the range from  126 to 798 mg/1  and  the mean was 386 mg/1.

     The results of three  susceptibility to separation test  runs are  present-
 ed in  Table 102.  The mean IR-Oil  content for the three runs of  330 mg/1
 after  one  hour of  settling is  moderately lower than  the mean of  386 mg/1  for
•twenty gravity separator effluent tests.

     The largest oil  drop  detected by  the particle size distribution  test in
 the  gravity separator effluent had a diameter of 49  urn.

 Miscellaneous  Brine Tests

     All other brine  test  results  for  ST131 are  listed in Tables 103, 104,
 105  and  106.   The  results  for  the following tests were in narrow ranges  for
 all  samples:   temperature, pH, and specific gravity.  These  parameters were
 therefore  not  examined for correlation  for  sample-to-sample  variations in
 effluent oil content  on ST131.  These  parameters will be discussed in a
 later  section  with respect to  variations between platforms.

     Only  one  ionic analysis test and  one sulfate reducing bacteria test per
 sample point were  run on ST131.   These  tests also are only significant with
 respect  to comparisons between platforms.

 Crude  Oil  Tests

     All crude oil  results are listed  in Tables  107  and 108.  The crude  oil
 temperature, specific gravity, and surface  tension test results all fell  in
 narrow ranges.

     The viscosity and boiling range distribution tests were limited  in  num-
 ber  to one or  two  and are of primary significance for comparisons between
 platforms.

     Two equilibration tests were  run,  each at a different oil/water  ratio.

     The limited number of tests  run on crude oil provided only a limited
 characterization of the crude  oil.
                                     191
-------
                 TABLE 102.  ST131  SUSCEPTIBILITY TO  SEPARATION TESTS ON GRAVITY SEPARATOR  INFLUENT
10
ro

Settling time.
0
Test Number 1
Day 1, 1300
IR-Oil, mg/1 2,686
IR-011, %
IR-Oil W/Silica Gel, mg/1 1,931
Test Number 2
Day 2, 1300
IR-Oil, mg/1 2,141
IR-Oil, %
IR-Oil W/Silica Gel, mg/1 1,763
Test Number 3
Day 7, 1300
IR-Oil, mg/1 40,000
IR-Oil W/Silica Gel, mg/1
Average
IR-Oil, mg/1 14,942
IR-Oil, %
IR-Oil W/Silica Gel, mg/1 1,847
2 5


1,007 756
(37) (12)
546


592 537
(16) (5)
525


1,679 1,259
1,091

1,093 851
26 8
721
15


588
(12)
-


310
(4)
-


923
-

607
8

minutes
30


462
(30)
-


955
(25)
-


588
-

668
28


60


361
(19)
-


193
(4)
-


437
-

330
12


120


210
(9)
126


168
(2)
126


340
252

239
6
168

0


5,373
-


1,259

-


200 ,000
-

68,877
-


        ( )  Percent of oil present in full sample that remains in bottom 1-liter of sample
             after settling.
-------
            TABLE 103.   ST131  SUPPLEMENTARY BRINE TESTS
Sample time
Day Hour
01 08
02 08
03 08
04 08
05 08
06 08
07 08
08 08
09 08
10 08
Mean
Minimum
Maximum
Temperature,
8—1
24.0
26.5
26.0
21.5
26.0
22.0
21.5
22.0
21.0
18.0
22.9
21.0
26.5
9— i
22.0
25.5
24.0
22.0
25.5
22.5
21.0
22.0
21.5
22.0
22.8
21.0
25.5
°C
9—0
23.0
25.0
19.0
22.5
25.0
22.5
21.0
22.0
23.0
23.0
22.6
19.0
25.0
9--0
6.2
6.1
6.2
6.7
6.6
6.6
6.1
6.2
6.3
6.2
6.3
6.1
6.7
Specific(1)
gravity
9—0
1.128
1.135
1.139
1.139
1.140
1.113
1.125
1.125
1.126
1.122
1.129
1.113
1.140
Note:  Sample point identification  numbers  (8--i, 9—i, 9—0) as
       shown on flow diagrams.

(1)    Specific gravity  is  reported at temperature shown in table
       above.
       TABLE 104.  ST131 BRINE TESTS AT MINOR SAMPLING POINTS
 Sample  time
 Day     Hour
                   IR-Oil,  mq/1
                    Sump (14--0)
                  Temperature,  °C
                    Sump  (14--0)
 08
 09
08
08
2309
1553
22.0
23.0
                                193
-------
            TABLE 105.   ST131  SULFATE  REDUCING  BACTERIA
Sample time
Bacteria per milliliter
Sump - Out (14--0)
Gravity Separator - In (8--i)
Flotation Unit - In (9—1)
Flotation Unit - Out (9—0)

Sample Day and Hour:  09 at 15
    100,000-1,000,000
       1,000,000
     10,000-100,000
     10,000-100,000
     TABLE 106.   ST131  IONIC ANALYSIS FLOTATION UNIT EFFLUENT
Constituent
       Concentration, mg/1
Sodium (Na)
Potassium (K)
Calcium (Ca)
Magnesium (Mg)
Barium (Ba)
Chloride (Cl)
Sulfate (S04)
Alkalinity (as HC03)
Iron (Total)
Sulfide (as H2S)
Total Dissolved Solids
Summation
Gravimetric
47,000
500
2,570
1,140
<5
80,000
145
183
18
0.13

131,000
138,000
Sample Day and Hour:  08 at 13
                               194
-------
           TABLE 107.  ST131 CRUDE OIL MISCELLANEOUS TESTS
                                                          (1)

Sample time
Day Hour
01 08
02 08
03 08
04 08
05 08
06 08
07 08
08 08
09 08
10 08
Mean
Minimum
Maximum
Temperature
°C
24.5
24.5
15.0
21.0
22.0
16.5
17.0
19.5
22.0
17.5
20.0
15.0
24.5
Specific^
gravity
0.840
0.838
0.847
0.843
0.840
0.841
0.842
0.842
0.840
0.845
0.842
0.838
0.847
Surface tension' '
dynes /cm
25
26
25
25
25
25
26
24
24
25
25
24
26
Sample time
Day    Hour
08
13
                          Viscosity at 37.77C
 Kinematic
centlstokes

   3.36
 Absolute
centipoise

   2.85
                          Equilibration at 82°C
                       Brine TDS * 131,000 mo/1
Oil /Water Ratio
IR-011, mg/1
IR-Oil W/Silica
IR-011 Filtered


Gel , mg/1
Brine , mg/1
4/1
35
23
17
4.4/1
35
23
18

(1)  Samples taken from oil LACT unit.
(2)  Specific gravity reported for temperature in table,
(3)  Surface tension measured and reported at ambient
     temperatures from 10.0°C to 25.5°C.
                                  195
-------
           TABLE  108.   ST131  CRUDE OIL  BOILING  RANGE  DISTRIBUTION
                                           Run
Initial Boiling Point, °C                  150
Final Boiling Point, °C                    480
Boiling range, °C                   Percent recovered

Below - 200                                61.7
  200 - 250                                22.6
  250 - 300                                 8.8
  300 - 350                                 1.6
  350 - 400                                 0.3
  400 - 450                                 0.1
  450 - 500                                 0.0

Total                                      95.1
                                     196
-------
                                 SECTION 11

                               PLATFORM  BDCCF5
GENERAL
     The ten-day testing survey was conducted on Platform BDCCF5 from April 1,
1980 through April 10, 1980.

     A description of the production facilities, the test program, and data
presentation and evaluation are presented in this section.

     Three survey team members arrived at the platform on March 31 and the
test equipment was set up the same day.  Oil company personnel unloaded the
equipment and provided living quarters, work space, sample taps, and the
utilities needed to conduct the program.

     The BDCCF5 Platform was located in shallow water.  The production plat-
form was unmanned, the only unmanned platform included in the survey.  The
quarters were about one kilometer away.  Operating personnel visited the plat-
form by boat at least once per day.  The complete testing survey was carried
out without interruption by weather, operating problems, or for any other
reason.

FACILITIES AND OPERATIONS

Production From Wells

     The number of wells producing was uniform from day to day.  All oil wells
produced continuously for the ten-day testing period.  One well producing only
gas, flowed from the sixth day to the tenth day.

     Nineteen wells were producing.  Five wells were flowing by formation
pressure, and the other fourteen wells were gas lifted.

     The estimated daily production for all wells was 180 m3/d (1,131 bpd) of
oil, 1,890 m3/d (11,895 bpd) of water, and 145,600 std m3/d (5,145 Mcfd) of
gas.  The calculated water cut was 91 percent.

     Sixty-seven percent of the oil was gas lifted, and eighty-eight percent
of the water was gas lifted.

Production Process System

     The flow of oil and water through the system is shown in Figure 65.

                                      197
-------
00
                                                                                 «> ' i   £~i~ 1 ~   "I !" PO?
                  (AHfLC POINT



                  IMTEKMITTfNT fLOW
                             Figure 65.  Flow  diagram, production process  system, BDCCF5.
-------
Design and operating data on major vessels are presented in Table 109.  The
oil/water/gas flow is from the wells to four low-pressure gas-liquid separa-
tors operating in parallel.

     A scale inhibitor, Tretolite WF-123, and a demulsifier, Tretolite BR-
4050, are added to the produced fluids ahead of the low-pressure separators.

     The oil/water flow from the four low-pressure separators is commingled
and then split into two streams to flow through two oil treaters (heater
treaters) in parallel.  Oil is drawn from the oil treaters to storage tanks.

     The primary water flow is from the oil treaters to two gravity oil/water
separators operating in parallel.  A combined stream flows from the gravity
separators to a flotation unit and then to discharge.

     A water treating chemical designed to aid in the separation of oil from
water, Tretolite JW-8206, is added at the flotation unit inlet.  The addition
rate varied from 0 to 12.3 dm3/d (3.2 gpd).

     The skimmings from the flotation unit are pumped to a sludge pit.

     Figure 66 is a flow schematic for the water handling system.  The water
flow rates in the figure are based on well test data.  The skimmings flow rate
is based on two measurements each day.

     The two gravity separators on BDCCF5 are cylindrical skim tanks.of almost
identical configuration.  They are 6.7 m (22 ft) in diameter by 4.9 m (16 ft)
high.  The operating water level is 4.2 m (13.75 ft).  Water enters each skim
tank through two 10 cm (4 in.) pipes projecting downward to about 0.3 m (1 ft)
below the water surface near one side of the tank.  The water flows from the
tank through a 15 cm (6 in.) pipe about 1.2 m (4 ft) from the bottom on the
opposite side of the tank.  It appears that there could be significant short
circuiting and turbulence of the flow in the gravity separators.  There is
not a generally accepted method of calculating the design capacity of these
gravity separators.

     The flotation unit (Monosep AG-20,000) is a proprietary unit with hydrau-
lic gas dispersion.  This type of unit was described in Section 7 and depicted
in Figure 19.  The unit on BDCCF5 has a design capacity of 3,180 m3/d (20,000
bpd) of water.  The average hydraulic loading was 1,890 m3/d (11,890 bpd), or
59 percent of design.

SITE SPECIFIC TEST PROGRAM

     The planned test program for brine samples is presented in Table 110.
The number of samples to be taken in ten days and the time the samples are to
be taken each day are listed.   The listed program was carried out with only
minor variations as will be observed later.

     In addition to the brine tests, the following tests were run on crude
oil samples:  temperature, specific gravity, viscosity, boiling range distri-
bution, equilibration, and surface tension.

                                     199
-------
                                       TABLE 109.   BDCCF5 VESSEL DATA SHEET
ro
O
O




Vessel description
Trade Name or Vessel Type
Design Parameters
Dimensions, m. (ft)
Diameter. O.D.
Length, S.S.
Length
Width
Height
Separation Surface Area. «2,(ft2)
Total
Per Cell
Volume. Qi3.(bbl)
Total
Oil Phase
Water Phase
Number of Cells
Flow Rate, m3/day.(bpd)'3'
Overflow Rate Per Cell. («3/d)/02.
Recycle Rate, Percent of Flow
Retention Time. «in.'3)
Average Operating Parameters
Temperature. °C(°F)
Pressure, kPag (psig)
Flow Rate. m3/d. (bpd)
Flow Rate. Percent of Design
Overflow Rate Per Cell. (»3/d)/w2.
Recycle Rate. Percent of Flow*3'
Froth Flow, Percent of Flow
1 Data for each of two tanks.
2 For water in separation tank only.
3 Based op effluent flow. Overflow
VESSEL DESIGNATION ON FLOM
5A.5B.5C t 50 6A & 6B(1)
Low pressure Low pressure
2-phase 3-phase
separators oil treaters
Vertical Vertical Cylinder
Cylinder Cone Bottom


3.0(10)
-
-
-
10.7(35)

7.2(78)
7.2(78)

-
_
29.6(186)
_
_
(bod/ft2) (3)
-
-

41(106)
517(75) 124(18)
945(5.945)
.
(bpd/ft2)(3) - 131(76)
-
• -

rate is surface area divided by flow rate.
DIAGRAM - FIGURE
8A 1 8B*1'
Gravity
separators
skin tanks
Vertical
Cyl inder


6.7(22)
-
-
.
4.9(16)

35(360)
35(380)

-
.
148(930)
.
,
-
.
-

41(106)
0
945(5.946)
_
27(16)
-
-


n-i
9
Flotation unit
hydraul ic
dispersed gas
Honosep
Model AG-20.000


-
ly\
5.0(16.5) 2
3.7(12) *
2.3(7.5) (2>

10.7(115)
10.7(115)

-
.
24.5(1S4){2'
1
3.180(20.000)
297(174)
400
11

41(106)
0
1,890(11.890)
59
177(103)
670
<1


-------
                          OIL THEATERS
                         {2 IN PARALLEL)
  SKIM TANKS
(2 IN PARALLEL)
FLOTATION UNIT
ro
o
               FROMLP
              SEPARATORS
            FLOW BALANCE IS NOT EXACT
            BECAUSE OF ROUNDING.
                  TO DISPOSAL PIT
                                                                                                      DISCHARGE
                                                              9F   9__,   9__0
                                                          m3/d 5    1890    I89O
                                                               3O  II.89O   11,890
                               Figure  66.   BDCCF5 water  handling system flow  schematic.
-------
OIL
THEATERS
>!,




GRAVITY


1 V
i i ^
1 ^

FLOTATION
UNIT


                                        TABLE  110.   BDCCF5 TEST  SCHEDULE  FOR THE MAJOR BRINE  TESTS
ro
o
IM
                                                                                            SAMPLE POINTS
                                              V
9--0 9


Field Tests
Infrared Oil
No. of
tests

20
Time of
tests

8.13
No. of
tests

20
*i
Time of
tests

8.13
88
No. of
tests

10
XO
Time of
tests

B

No. of
tests

10
Xo
Time of
tests

8
68
No. of
tests

10
f*0
fine of
tests

8
6K
No. of
tests

10
-0
Time of
tests

8
          tempera hire
          PH
          Water Specific Gravity.,.
          Water Surface Tension »*'
          ID-Oil W/Silica Gel
          Ill-Oil Filtered Brine       ...
          Susceptibility to Separation'J'

         aboratory Tests
          Gravimetric Oil
          Suspended Solids
          Ionic Analysis
          Bacterial Culture         ...
          Particle Size Distribution*"
                              10
                              10
                              10
                              10
                              20
                              20
  8
  B
  B
  8
8,13
8.13
10
10
10
10
 3
           10
10
10
10
 B
 8
 a
13
                              40   8.10.13.15      10      8           -
                              10        8         10      8           -
                               I       (1)                             -        -
                              A maximum of  five tests at sample points selected in the field.
                               3       13          -                  3       13          3
                                                                                                             13
          1!
Sampling times not shown will be field  scheduled.
Extra  samples when ID-Oil Is high.
IR-Oil w/stllca gel at  0. 5. and 120 minutes.
ID-Oil. IR-011 M/sllica get, and filtered brine tests at sane time.
                                                    NOTE:  Time of tests listed Is by military hour.
-------
OPERATIONAL DATA AND OBSERVATIONS

     Measurements, observations, and records of operations are reported in
this subsection.

Flow Monitoring

     Continuous flow monitoring was not accomplished on BDCCF5.  The rented
Doppler meter was tried at several points in the system, but positive
readings were not obtained.  The apparent problem was .that the flowing
streams did not contain sufficient particulate matter, or sufficient turbu-
lence to provide input to the monitor.

     It is believed that variations in flow during the program were minor.
All oil wells produced continuously, and there were not any significant re-
cycle flows.

Well Test Data

     The well test data provided by the operator are presented in Table 111.

Pressure Drops Through System

     Flowing tubing pressures were obtained from well test records.  The
pressure of major vessels was recorded twice per day.  Pressure drops in the
system are reported in Table 112.  The data were recorded to permit examin-
ing the theory that turbulence occurring with the pressure drops at chokes
and valves may form small particle dispersions that are difficult to remove
in the separation equipment.

Chemical  Addition

     Three chemicals were added continuously by small metering pumps.

     A scale inhibitor, Tretolite WF-123, was added to the manifold ahead of
the low-pressure separators.  The addition rate was uniform at just under
0.95 dm3/d (0.25 gpd).  A demulsifier, Tretolite BR-4050, was added to the
same manifold at four different points.  The addition of the demulsifier was
also uniform at a total rate of 5.3 dm3/d (1.4 gpd).

     A flotation aid, Tretolite JW-8206, was added to the inlet of the flo-
tation unit.  The addition rate was not uniform.   An addition rate for each
major sampling time is presented in Table 113.

Observations and Operator Reports

    Any occurrences observed by the survey team or reported by the operators
were recorded if they had potential significance with respect to effluent
oil content.

    Production rates were very uniform for the ten-day period.  There were
not any changes that affected liquid flow rates.   Three wells producing

                                     203
-------
                                                          TABLE  111.   BDCCF5 WELL  TEST  DATA
ro
o
Uell Forwation
f lowing to Low Pressure
6-20
B-47
8-80
B-97
Bill
Total (Average)
TVD
7F
Separator
1.524
1,520
8.16S
8,780
1.530
-
Gas
HcW

584
2.043
110
ISO
1.640
4.527
on
Ep3

0
0
120
251
0
371
Water
"tjxT

0
0
1.112
307
0
1.419
lift gas Pressure, pslg
'"Mcfd~ SIBHP~ FTP

0
0
0
0
0
-

440
445
ISO
580
475
-
Choke size
1/64 in.

28
48
open
16
48
-
API gravity

_
.
28.9
33.5
_
(31.2)
Days of
production

AH
All
All
All
6-10

              Gas Lift to low Pressure Separator
B-27
B-30
B-32
8-720
B-73
B-76
B-78
B-86
B-91
fl-99
B109
8119
8121
B122
Total (Average)

Combined Total (Average)
8,155
8.275
8.395
8.100
8.020
8.140
8.015
8.250
8.400
4.430
4.400
7.750
5.760
8.240
-
5
18
228
48
10
23
80
71
73
4
6
IS
15
22
618
10
26
9
102
20
41
153
150
132
18
16
26
25
32
760
1,005
850
3
918
1.730
1.867
1.664
0
1.332
54
24
106
815
8
10,476
489
478
7
147
602
485
438
399
422
473
232
428
371
421
5.392
                                  130
                                  260
                                  100
                                  100
                                  200
                                  210
                                  225
                                  120
                                  180
                                  180
                                  120
                                  200
                                  290
                                  125
                                   open
                                   open
                                   open
                                   open
                                   open
                                   open
                                   open
                                   open
                                   open
                                   open
                                   open
                                   open
                                   open
                                   open
                                                  5,145    1.131
11.895
5.392
 28.6
 35.7
 36.5
 28.2
 28.4
 29.5
 30.0
 28.5
 29.5
 28.3
 29.S
 34.9
 35.7
 3,6.8
(31.4)

(31.4)
All
All
All
All
All
All
All
All
AH
AH
All
AH
All
All
-------
               TABLE 112.  BDCCF5 PRESSURE DROPS THROUGH SYSTEM
 Location
Pressure,
  kPag
 (psig)
                        Pressure drop,
    Pressure drop,          kPag
point or description       (psig)
 Low Pressure       690-4,000
 Wells, Flowing    (100-580)
 Tubing Pressure
 Low Pressure
 Separators
 Oil  Treaters
 Skim Tanks
480-580
(70-84)
  124
  (18)
                      chokes,
                      pipes
    valves,
    pipes
                                          valves,
                                          pipes
                         110-3,520
                         (16-510)
356-456
(52-66)
                           124
                           (18)
 primary gas were off for a short time after samples were taken on the second
 day.  There were not any operational  problems that disrupted the program.

     On Day 2, just after the 0800 samples were taken, a survey team member
 unintentionally left the valve from the flotation chemical  storage tank off
 after a flow rate check.  When turned on later that day, the pump did not
 work.  Flotation chemical feed was restarted on Day 3 at 0940 after a check
 valve was replaced.

     On Day 10 at 1000 9.5 dm3 (2.5 gallons) of biocide was  added to the 8A
skim tank.  The biocide was Tretolite X-CIDE 102.  The operators expect foam-
ing in the flotation unit when biocide is added.  Minor foaming did occur in
the flotation unit.  Any effect on flotation influent and effluent oil content
should have been detected in the 1300 sample.  No effect on  oil content was
measured.

 DATA PRESENTATION AND EVALUATION

     Comprehensive data tables, summary tables and graphs for BDCCF5 are inter-
 spersed in the text.

 Effluent Oil Content

     Table 114 presents a listing of oil  content test results for the major
 sampling points.  Figure 67 presents  a plot of GR-Oil in and out of the
 flotation unit versus time.  Figure 68 presents the same plot for IR-Oil
 content.
                                      205
-------
               TABLE 113.   BOCCF5 FLOTATION CHEMICAL ADDITION

Day
01

02
03

04

05

06

07

08

09

10

Hour
08
13
08
13
08
13
08
13
08
13
08
13
08
13
08
13
08
13
08
13
Addition i
dmj/d
5.2
5.2
5^(2)
(T- *
6.6
12.3
11.4
7.6
7.6
6.6
11.4
11.4
11.4
11.4
11.4
11.4
11.4
10.4
10.4

ppmv
3
3
1(2)
0^ '
3
7
6
4
4
3
6
6
6
6
6
6
6
6
6
Mean
(1)
(2)

The addition
through the
Not included

rate for
flotation
in mean.

Tretolite
unit.
9.4
JW-8206 based on
5
average water

flow
     The tabulated data and time-indexed plots show that the flotation in-
fluent oil content is exceptionally uniform from sample to sample.  The flo-
tation effluent oil content is also quite uniform except for Day 2 and Day 3.
The high oil content values on these days occurred when the survey team un-
intentionally shut off the flotation chemical  feed.  The importance of flo-
tation chemical for effective oil flotation is demonstrated for BDCCF5.

     The ranges of test results, not including those when chemical was not
added, are as follows:

     Flotation Effluent GR-Oil - 14 to 45 mg/1,
     Flotation Effluent IR-Oil - 25 to 52 mg/1,
     Flotation Influent GR-Oil - 70 to 101 mg/1,
     Flotation Influent IR-Oil - 91 to 152 mg/1.

     Flotation unit effluent oil content histograms for the two test methods
are presented in Figure 69 and Figure 70.  Figure 71 is a regression plot of
effluent GR-Oil versus IR-Oil.   In comparing oil content test results by the
two methods, it should be remembered that the samples were taken about one


                                     206
-------
                                                  TABLE  114.    BDCCF5 MAJOR  BRINE  TESTS
ro
O
Flotation
Sample time
Day Hour
01 08
01 10
01 13
01 15
02 08
02 10
02 13
02 IS
03 08
03 10
03 13
03 IS
04 08
04 10
04 13
04 IS
05 08
0£ 10
05 13
OS IS
06 08
06 10
06 13
06 IS
0? 08
07 10
07 13
07 15
08 08
08 10
08 13
08 IS
09 08
09 10
09 13
09 IS
10 08
10 10
10 13
10 15
Mininun
Maximun
GR-Oil
»g/l
70
v
_
.
73
_
-
-
79
.
.
-
73
.
_
.
101
.
.
_
91
_
.
.
75
_
.
_
80
.
.
„
81

_
_
80
in-on
mg/1
134
_
108
.
100
-
130
-
104
-
152
-
121
.
91
-
108
-
100
-
113
-
108
-
95
.
104
_
117
-
113
_
130

113
_
113
IR-011
unit Influent
w/sillca gel
Dispersed Soluble
mg/l mg/1
69
.
.
.
61
_
65
_
_
.
39
_
(9-1)
Filtered
brine
IR-011
«9/l
9
.
.
.
9
.
Flotation unit
Surface
tension
dynes/cm
62
-
-
.
65
.
GR-011 IR-011
B9/1
33
38
39
45
33
36
rag/ 1
49
-
50
.
52
.
77(C) 126(C)
.
56
-
.
-
13
.
.
_
69
.
_
.
74
_
_
.
56
_
_
.
69
_
_
..
39

_
_
26
.
48
-
-
.
108
.
.
.
39
-
.
.
39
_
_
.
39
_
_
_
48
_
_
_
91

_
„
87
-
9
.
_
.
7
-
_
.
10
.
.
.
9
.
.
.
9
_
.
..
11

.
—
9

_
_
11
-
61
-
_
-
67
-
-
.
62
-
_
_
64
.
.
_
64
_
„
_
67
_
_
.
63

_
.
64
81 (C
49(C
26(C
88(C
84(C
21
14
18
23
24
22
26
32
32
24
31
25
14
19
22
22
21
23
25
25
21
23
24
27
25
-
64(C)
-
139(C)

30
.
25
.
33
.
32
_
47
_
40
.
29
.
29
_
33
.
33
_
33

32
_
35
IR-Oil
w/slllca gel
Dispersed Soluble
»g/l »g/l
38
_
38
-
43
_
65{C)
.
52(C)
-
104(C)

18
-
13
.
25
-
25
_
38
_
31
-
20
.
22
_
23
„
25

19

19

21
5(A)

-
70
101
100
-
91
152
_
-
13
74
_
-
39
108
-
-
7
11
_
-
61
67
25
28
14
45
33

25
52
21

13
43
11
.
12
_
9
_
61{C)

12(C)

35(C)

12
.
12
_
8
_
7
.
9
.
9
.
9

7

10

8

14

13

14

12

7
14
effluent (
Filtered
brine
IR-011
ma/1
8
.
9
.
10
_
11(C)
-
8(C)
.
13(C)

6
.
8
.
10
.
10
_
8
_
8
.
9
_
7

8
_
8

9

9

8

9

6
10
9--01

Surface Flow rate
tension Out
dynes/on n /d
55 .890
.890
.890
.890
60 .890
.890
.890
.890
58(C) .890
,890
.890
.890
62 .890
.890
.890
.890
64 .890
.890
.890
.890
59 .890
.890
.890
.890
63 .890
.890
.890
.890
60 .890
.890
.890
.890
64 .89°
.890
.890
.890
63 .390
.890
.890
.890
55
64
Skimmings
~2VT~
2
2
11
11
4
4
7
7
7
7
11
11
3
3
3
3
4
4
3
3
4
4
3
3
3
3
S
5
4
4
4
4
4
4
3
3
4
4
5
S
2
11
          (A)    Not  included in statistical analysis.  Appears inconsistent with other IR-Oil, GR-011. and Ift-Oil W/Sllica Gel Tests.
          (C)    Hot  included In statistical analysis.  The survey team Inadvertently shut off the feed of flotation chemical  to the system.
-------
rv>
o
00
            300-
            200-
     OR-OIL

     mg/l
            WO-1
            soo-
            20O-
     IR-OIL

     mg/l
            100-
                                                                           INFLUENT
                                                             I

                                                            DAY
               6
IO
                         Figure  67.   BDCCF5  flotation  unit  performance,  GR-oil  vs  time.
INFLUENT
                                                            DAY

                         Figure 68.  BDCCF5 flotation unit performance,  IR-oil \is  time.
                                                                                             9
                                                    10
-------
FREQUENCY
     %
           70-
           60-
            50-
           40-
            30-1
            20-!
                                                      5*26
              0        10       20       30        40        50       60
                                      GR-OIL,mg/l
    Figure 69.  BDCCF5 flotation unit effluent, GR-oil histogram.
           70-
            SO-
FREQUENCY
    %
            40-
            30-
            20-
            10-
                                T
T
                  T
T
                                                      n* 17
                                                      Is 36
                                                      s -3.2
                        I
                        10
20
30
40
        60
    Figure 70.   BOCCF5 flotation unit effluent, IR-oil  histogram.
                                  209
-------
ro
»-•
o
                  50
                   4O
        GR-OIL

         rng/l
                   20
                   10
                       T  I  II  j  I  I  I  I  j
                               GR-OIL* O.53+O.69 (IR-OIL)

                                    r * O.9I
                •  •
                                                        •   •
                                 I  I  I  .  t   I
     I  I  I
I  I  I  I   I  j   I  I  J  I  I  I  I
J  I   1  i  I  I  I
                                to
20
                        SO
     60
                                   30          40


                                    IR-01L,  mg/l


Figure 71.  BDCCF5 flotation unit effluent,  infrared-gravimetric regression.
-------
minute apart from a flowing stream.  Therefore, the comparisons  include  time-
dependent sample differences as well as normal sampling and testing varia-
tions.

     Table 115 presents a summary comparison of test results by  the two
methods.

                 TABLE 115.  BDCCF5 FLOTATION UNIT EFFLUENT
	GR-OIL AND IR-QIL COMPARISON	

                                           Oil content
                                         GR-Oil
IR-Oi'
Number of tests,
Mean, (x) , mg/1
Minimum, mg/1
Maximum, mg/1
(n)



Standard Deviation, (s), mg/1
33
26
14
45
6.9
17
36
25
52
8.2
                                            Paired tests
Number, (n)
Mean of Differences
Standard Deviation,
, (A), mg/1
(SA), mg/1
17
10.6
3.7

     The mean oil content of the flotation effluent is 10 mg/1 higher by the
 IR-Oi1 test method than by the GR-Oil test.  The regression plot and the
 correlation coefficient of 0.91 shown in Figure 71 illustrate a significant
 relationship between results by the two test methods.  This significant
 relationship is confirmed by the standard deviation of only 3.7 mg/1 for
 differences in paired tests as presented in Table 115.

     All test results for dispersed oil and soluble oil as measured by the
 IR-Oil w/Silica Gel test are listed in Table 114.  A summary of these test
 results is presented in Table 116.

                  TABLE 116.  BDCCF5 SUSPENDED SOLIDS SUMMARY



Analysis or test
IR-Oil
Dispersed Oil
Soluble Oil
Flotation
Range
mg/1
25-52
13-43
7-14
effluent
Mean
mg/1
36
26
10
Proportion
of total ,
percent
100
72
28

Note:  Table includes only IR-Oil tests when an IR-Oil w/Silica Gel test
       was run.
                                     211
-------
     On average, 28 percent of the oil in the effluent was soluble oil and
72 percent was dispersed oil.

     Linear regression plots of dispersed oil versus IR-Oil and GR-Oil are
presented in Figure 72.  There is a significant correlation between dispersed
oil and total oil as measured by both standard tests.  Extrapolations of the
linear regression lines to zero dispersed oil indicate a residual IR-Oil of
12 mg/1 and a residual GR-Oil of 9 mg/1  after all  dispersed oil is removed.

     The mean soluble oil content of the flotation influent was 60 mg/1,
significantly higher than the mean of 10 mg/1 of the flotation unit effluent.

Surface Tension

     All surface tension test results are listed in Table 114.  The mean
surface tension of the flotation influent is 64 dynes/cm and of the flota-
tion effluent is 61 dynes/cm.  The range for flotation effluent test results
was from 55 dynes to 64 dynes/cm.  The linear regression equation for
effluent IR-Oil and surface tension is:


              IR-Oil = 219 - 2.94 (Surface Tension)
                   r = -0.73


     The test results on Day 2 when the system was upset were  included in
calculating the regression equation.  A decrease in oil content is indicated
for an  increase in surface tension.

Suspended Solids

     Suspended solids test data are presented in Table 117 for major sampling
points.

     A  suspended solids summary for BDCCF5 is presented in Table 118.

     Most of the solids in the flotation influent and effluent were Freon
soluble.  The concentrations of Freon insoluble solids were low, and no fixed
solids  were present.

     Figure 73 presents time-indexed plots of Freon insoluble  suspended
solids  in the flotation unit influent and effluent, and of flotation effluent
dispersed oil.  All samples were taken at the same time, 0800  each day.  The
plotted data do not demonstrate a distinct pattern that the dispersed oil
content of the effluent is higher when suspended solids are higher in the
flotation unit influent or effluent.  As discussed in Section  18, the sus-
pended  solids test method may not have sufficient precision to provide mean-
ingful  results at the solids concentrations  in the BDCCF5 brine.

Filtered Brine

     The filtered brine  IR-Oil test results on BDCCF5 flotation influent were
in the  range from 7 to 11 mg/1.  Those on the flotation effluent were in the

                                     212
-------
       7O—
       60-
       30-
       40-
TOTAL   _
  OIL
 mg/l


       30-
       20-
        10-
        0-
                    i  i   i  1   r
                                      1   in   r
                                 T  I
• TOTAL IR-OIL VS.  DISPERSED   IR-OIL
TOTAL IR-OIL =12+0.92 ( DISPERSED  IR-OIL)
 r s 0.96
• TOTAL GR-OIL VS.  DISPERSED  IR-OIL
TOTALGR-OIL'9 + 0.64 ( DISPERSED  IR-OIL)
rsO.88
                         TOTAL IR-OIL-  DISPERSED IR-OIL
                                                  •TOTAL  GR-OIL-  DISPERSED ' IR-OIL
            I   I  I   I  I   I  I   1
            0           10
          i  I
            20
i  T
j  r  i  r  ill!   iii
30          40           »
                                    DISPERSED  IR-OIL,mg/l
                 Figure  72.   BDCCF5 flotation unit  effluent,
                    total  oil  - dispersed oil regression.
                                      213
-------
                   TABLE 117.  BDCCF5 SUSPENDED SOLIDS TESTS
notation unit, 1n (9--1)
•
Sample time
Day Hour
01 08
02 08
03 08
04 08
OS 08
06 08
07 08
08 08
09 08
10 08
Hlnlmun
Maximum

Total
•8/1
60
49
61
40
43
47
34
37
43
38
34
61
Freon
soluble
ntg/1
50
43
55
36
40
43
32
32
39
33
32
35
Freon
Insoluble
rng/1
11
6
5
4
3
5
2
4
5
5
2
11
Acid
soluble
rag/1
11
6
4
4
3
5
2
4
4
5
2
11

Fixed
mg/1
0
0
2
0
0
0
0
0
0
0
0
2

Total
rogv'l
57
40
38
35
32
42
28
20
25
33
20
57
Flotation unit, out (9--0)
Freon
soluble
mg/l
32
26
26
16
17
26
16
13
16
20
13
32
Freon
Insoluble
mg/1
25
15
13
20
14
15
12
7
10
13
7
25
Acid
soluble
mg/1
24
15
9
20
14
15
12
7
9
13
7
24

Fixed
mg/T
1
0
4
0
0
1
0
0
1
0
0
4
                TABLE 118.  BDCCF5 SUSPENDED SOLIDS SUMMARY
Suspended Solids
Average suspended solids, mg/1
    9—1              9--0
Total
Freon Soluble
Freon Insoluble
Acid Soluble
Fixed
45
40
5
5
0
35
•21
14
14
0

range from 6 to 10 mg/1.   These test results  exhibit exceptional  consistency.
The concentration of oil  that was not removed by filtration  was  essentially
the same in the flotation influent and effluent brines.

Flotation Unit Performance

     Figure 74 is a regression plot of IR-Oil in and out of the  flotation
unit.  The effluent oil content increases slightly as the influent increases.
However, the correlation coefficient of 0.27  is low.  Only minor significance
can be attached to the relationship of flotation influent and effluent oil
content.

     Flow was not monitored on BDCCF5.  Therefore, it is not possible to
examine the oil content test results for sample-to-sample variations with
hydraulic loading.

Gravity Separator Performance

     Two gravity separators, 8A and 8B, were  operating in parallel.  The brine

                                     214
-------
                 40
ro
»-»
en
                 3O




      CONCENTRATION
           mg/l
                 20
                  10
                                     EFFLUENT  DISPERSED OIL
-A
  \
-  \
                         EFFLUENT S.S.



                             INFLUENT S.S.
                                               I	I
                                         5         6


                                            DAY
                                                                                                          10
                   Figure 73.  BDCCF5 flotation  unit Freon insoluble  suspended solids.
-------
ro
t->
CT>
               too
                BO
         7O
FLOTATION
   UNIT  60
 EFFLUENT
  IR-OIL
  mg/l   50

         40
                30
                20
                10
                          IR-OIL out = IStO.19 (IR-OIL in)
                                   t » 0.27
                          20
                                                                     • I •
                                                                           I
                             40
140
                   60       80        100        120
               FLOTATION  UNIT INFLUENT  IR-OIL,    mg/l

Figure 74.  BDCCF5 flotation unit in-out IR-oil regression.
160
                                                                                                       ISO
-------
oil contents in and out of the separators are listed in Table  119.  The
6A-0 and 6B-0 samples were taken at the outlets of the two oil treaters  ahead
of the gravity separators.  The brine effluents from both oil  treaters flow-
ed to both gravity separators, so that it was not possible to  know  the exact
volume or oil content of the gravity separator influents.  The IR-Oil content
range for the influents was 208 to 438 mg/1.

            TABLE 119.  BDCCF5 BRINE TESTS AT MINOR SAMPLING POINTS

Sample time IR-Oil, mq/1
Day Hour 6A-0 6B-0 8A-0
Temperature, °C
8B-0 6A-0 6B-0 8A-0 8B-0
  01
  02
  03
  04
  05
  06
  07
  08
  09
  10
08
08
08
08
08
08
08
08
10
10
  Mean
  Minimum
  Maximum
208
226
334
234
243
234
239
265
234
230

245
208
334
429
234
364
377
278
299
330
230
438
434

341
230
438
781
191
200
173
147
147
152
195
173
147

231
147
781
 91
 82
 91
 87
113
113
 68
 91
100
 87

 92
 68
113
38.0
38.0
38.0
38.0
35,
38,
39
38
39.0
,5
.0
39.0

38.2
35.5
39.5
42.5
44.0
44.0
42,
42,
43.
45,
45.0
44.0
44.5

43.8
42.5
45.5
        .5
        .5
        .5
        .5
41.5
40.0
40.5
41.0
  .5
  .5
39,
40,
41.0
42.0
40.5
41.0

40.8
39.5
42.0
43.0
41.0
42.0
41,
40,
.5
.0
42.0
41.5
42.0
41.0
41.5

41.6
40.0
43.0
  Note:  6A-0 is the 6A
         6B-0 is the 6B
         8A-0 is the 8A
         8B-0 is the 8B
               heater treater effluent.
               heater treater effluent.
               gravity separator effluent.
               gravity separator effluent.
     The IR-Oil contents of the effluents of the gravity separators are list-
ed under 8A-0 and 8B-0 in Table 119.

     The oil contents of the combine gravity separator effluents are listed
under 9—i  in Table 114.  The 9—i  test results also represent the flotation
unit influent.

     The range of IR-Oil test results representative of gravity separator
effluents are as follows:
          Separator, 8A-0
          Separator, 8B-0
          Combined,  9—i

     The oil  contents at i
                   147 to 781 mg/1
                    68 to 113 mg/1
                    91 to 152 mg/1

                  -0 and 9—i were quite consistent.

                             217
                                             The effluent
-------
oil content of separator 8A was both higher and less consistent than that of
separator 8B.  The reason for the difference was not determined.

     The results of the susceptibility to separation tests for sampling point
9—i are presented in Table 120.  These test results show that additional
oil can be removed by static settling even though the oil contents of the un-
settled samples were low by comparison to other gravity separator effluents.

Miscellaneous Brine Tests

     All other brine tests for BDCCF5 are listed in Tables 121, 122, and 123.
The results for the following tests were in narrow ranges for all samples:
temperature, pH, and specific gravity.  These parameters were therefore not
examined for correlation with sample-to-sample variation in effluent oil
content.  These parameters will be discussed in a later section with respect
to variations between platforms.

Crude Oil Tests

     All crude oil test results are listed in Tables 124 and 125.  The crude
oil temperature, specific gravity, and surface tension test results all fell
in narrow ranges.

     The viscosity and boiling range distribution tests were limited in
number to one or two and are of primary significance for comparisons between
platforms.

     Two equilibration tests were run, each at a different oil/water ratio.

     The limited number of tests run on crude oil provide only a limited
characterization of the crude oil.  Between platform comparisons will be
presented in Section 17.
                                     218
-------
             TABLE 120.  BDCCF5 SUSCEPTIBILITY TO SEPARATION  TESTS  ON GRAVITY SEPARATOR INFLUENT
ro
»-•
vo


Test Number 1
Day 3, 1300
IR-Oil, mg/1
IR-011 W/SIIIca Gel, mg/1
Test Number 2
Day 5, 1000
IR-011, mg/1
IR-011 W/ Silica Gel, mg/1
Test Number 3
Day 6, 1300
IR-011, mg/1
IR-011 W/Sillca Gel , mg/1
Average
IR-011, mg/1
IR-011 W/ Silica Gel, mg/1

0
152
104
104
69
108
39

121
71
Settling time, minutes
2 5 15 30 60
121 121 91 78 62
61
100 - 59 54 47
95 85 76 66 57
26 -

105 103 75 66 55
44

120
56
44
43
37
60
53

53
45

0
156
91
113

120
-------
            TABLE 121.   BDCCF5  SUPPLEMENTARY BRINE TESTS
 Sample  time
 Day     Hour
             Temperature,  °C
             9—i
           9—0
                                   Specific(1)
                                    gravity
                          9—0
 01
 02
 03
 04
 05
 06
 07
 08
 09
 10

 Mean
 Minimum
 Maximum
08
08
08
08
08
08
08
08
08
08
42.0
40.
41.
41.0
39.5
41.0
41.5
42.0
40.5
41.5

41.1
39.5
42.0
42.0
40.0
41.0
41.
39,
40.
40.
42.0
40.0
41.5

40.9
39.5
42.0
.5
,5
,5
,5
6.8
6.7
6.8
6.7
6.6
6.8
6.6
6.7
6.6
6.7

6.7
6.6
6.8
1.091
1.094
1.094
1.094
1.098
1.094
1.095
1.097
1.095
1.094

1.095
1.091
1.098
Note:  Sample point identification  numbers  (9—i, 9--0) as shown
       on flow diagrams.

(1)    Specific gravity is  reported at  temperature shown in table
       above.
                TABLE 122.   BDCCF5 REDUCING BACTERIA
Sample point
                               Bacteria per milliliter
Heater Treater - Out (6A-0)
Heater Treater - Out (6B-0)
Gravity Separator - Out (8A-0)
Gravity Separator - Out (8B-0)
Flotation Unit - Out (9—0)

Sample Day and Hour:  09 at  15
                                         0
                                         0
                                   10,000-100,000
                                         0
                                         0
                                 220
-------
    TABLE 123.  BDCCF5 IONIC ANALYSIS FLOTATION UNIT EFFLUENT

Constituent                                  Concentration, mg/1
Sodium (Na)                                        38,250
Potassium (K)                                         256
Calcium (Ca)                                        1,360
Magnesium (Mg)                                        401
Barium (Ba)                                            98
Chloride (Cl)                                      71,200
Sulfate (SOd)                                           6
Alkalinity (as HCOs)                                  366
Iron (Total)                                            6
Sulfide (as H2S)                                        0.15

Total Dissolved Solids
     Summation                                    112,000
     Gravimetric                                  108,000

Sample Day and Hour:  08 at 13
                                221
-------
          TABLE 124.  BDCCF5 CRUDE OIL MISCELLANEOUS TESTS
                                                           (1)
Sample time
Day    Hour
                Temperature
             Soecific
             gravity
                                      ,-,(2)
             Surface tension
                dynes/cm
                                                                    (3)
01
02
03
04
05
06
07
08
09
10
08
08
08
08
08
08
08
08
08
08
27.0
32.0
34
33
30
32
33
30.0
31.0
34.5
0.866
0.861
0.861
0.861
0.865
0.862
0.861
0.865
0.864
0.861
27
28
27
28
28
28
28
28
28
27
Mean
Minimum
Maximum
                   31.8
                   27.0
                   34.5
              0.863
              0.861
              0.866
                    28
                    27
                    28
Sample time
Day    Hour
08
13
                   Viscosity at 37.77°C
                 KinematicAbsolute
                centistokes     centipoise
9.43
  8.26
Oil/Water Ratio
IR-Oil, mg/1
IR-Oil U/Silica
IR-011 Filtered
                          Equilibration at 82°C
                       Brine TDS 3 112,000 mg/1
         Gel, mg/1
         Brine, mg/1
   4/1
    90
    10
    81
  0.1/1
   15
    3
   17
(1)  Samples taken from oil LACT unit.
(2)  Specific gravity reported for temperature in table.
(3)  Surface tension measured and reported at ambient temperatures
     from 19.5°C to 24.0°C.
                                 222
-------
           TABLE 125.  BDCCF5 CRUDE OIL BOILING RANGE DISTRIBUTION
                                           Run
Initial Boiling Point, °C                  150
Final Boiling Point,  °C                    480
Boiling range, °C                   Percent  recovered

Below - 200                                45.9
  200 - 250                                24.5
  250 - 300                                22.5
  300 - 350                                  5.6
  350 - 400                                  1.3
  400 - 450                                  0.2
  450 - 500                                  0.0

Total                                     100.0
                                      223
-------
                                 SECTION 12

                               PLATFORM SS107
GENERAL
     The ten-day testing survey was conducted on Platform SS107 from March 6
through March 15, 1980.

     A description of the production facilities, the test program, and data
presentation and evaluation are presented in this section.

     Four survey team members arrived at the platform on March 5 and the test
equipment was set up the same day.  Oil company personnel unloaded the equip-
ment and provided living quarters, work space, sample taps, and the utilities
needed to conduct the Program.

     The complete testing survey was carried out without interruption by
weather, operating problems, or for any other reason.

FACILITIES AND OPERATIONS

Production From Wells

     Five wells were producing.  Two wells were flowing by formation pressure,
and the other three wells were gas lifted.  Four wells shut in on Day 6 during
the 0800 sample period.  Three wells were opened after 15-20 minutes and the
fourth after about one hour.

     All production flowed or was gas lifted to the low-pressure gas/liquid
separator.  The average daily production calculated from well test data was
97 m3/d (610 bpd) of oil, 633 m3/d (3,979 bpd) of water, and 13,300 std m3/d
(470 Mcfd) of gas.  The calculated water cut was 87 percent.

     The measured oil production for the ten-day period averaged 89 m3/d (560
bpd) or 8 percent less than the calculated production.  The measured water
production averaged 733 m3/d (4,610 bpd) or 16 percent more than the calcu-
lated production.

     Forty-two percent of the oil was gas lifted, and sixty-two percent of the
water was gas lifted.

Production Process System

     The flow of oil and water through the system is shown in Figure 75.

                                      224
-------
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                        POINT  --- IMTMMITTENT FLOW
                               Figure 75.   Flow diagram, production process  system,  SS107.
-------
Design and operating data on major vessels are presented in Table  126.
The oil/water/gas flow is from the wells to the low-pressure gas-liquid
separator.  The high- and low-pressure gas from another platform flows
through separators on SS107 before being compressed.  The operator estimated
that the liquids from these two separators would be about 3 m3/d.

    A demulsifier, Tretolite RN3003, is added to the produced fluids ahead of
the low-pressure separator.  A scale inhibitor, Tretolite SP175, is added to
the fluids downstream of the low-pressure separator.

    The fluids flow from the low-pressure separator to the oil treater.  Oil
flows from the treater to the settling tank.  The water flows from the oil
treater to the flotation unit and is then discharged.

    Figure 76 is a flow schematic for the water streams to and from the oil
treater and flotation unit.  The primary flow is produced water from the
low-pressure separator which averaged 874 m3/d.

    The liquid from the compressor scrubbers also flows to the oil treater.
The operator estimated this flow to average 10 dm3/d.

    Miscellaneous open drains discharge to the skim sump or skim pile.  Any
oil that accumulates on the skim sump or pile is pumped to the oil treater
at night.   Settlement tank bottoms are pumped once per week at night.

    The flow from the oil treater to the flotation unit was monitored con-
tinuously after 1300 on Day 1 with an orifice-plate type flow meter.  The
flotation unit froth was pumped to the oil treater.  The froth flow was
monitored for the first three days with a positive-displacement type flow
meter.  After 1300 on Day 3, the froth flow was estimated based on the time
to fill the flotation unit launder.   The effluent flow was calculated by
subtracting the froth flow from the flotation unit inlet flow.

    A water treating chemical, Tretolite FR 98D was added to the flotation
unit influent.  The addition rate varied from 4.5 dm3/d (1.2 gpd) to 19 dm3/d
(5 gpd).

    The oil treater is a dual purpose unit providing for the gravity sepa-
ration of water from oil in preparation for sale of the oil.  The treater
also provides the primary separation of oil from water to prepare the water
for treatment by flotation.

    The oil treater is a vertical cylindrical cone-bottom tank.   The treater
is 3.05 m (10 ft) in diameter and 9.91 m (32.5 ft) seam to seam.  The water
outlet is near the bottom seam and the level control is with a valve.  The
water volume above the water outlet is 20 m3 (126 bbl).  At the average
water flow rate of 874 m3/d (5,497 bpd), the calculated average retention
time would be 33 minutes.

    The flotation unit (Wemco 1+1, Model 66) is a proprietary four-cell unit
with mechanical gas eduction.  This type of unit was described in Section 6
and is depicted in Figure 6.  The design flow for the unit is 2,460 m3/d

                                     226
-------
                                                    TABLE 126.    SS107  VESSEL DATA SHEET
ro
Vessel description
Trade Name or Vessel Type
Design Parameters
Dimensions. •. (ft) .
Diameter. 0.0.
Length. S.S.

5A2
Low pressure
2-phase
separator
Vertical
Cylinder

1.3(4.3)
3.2(10.5)
VESSEL DESIGNATION
5B1
Low pressure
2-phase
separator
Vertical
Cylinder

1.3(4.3)
3.2(10.5)
ON FLOW DIAGRAM - FIGURE
6
Oil treater
Vertical Cylinder
Cone-Bottom

3.05(10)
9.91(32.5)
12-1
9
Flotation unit
mechanical
dispersed gas
Ueroco
Model 66

-
                  Length
                  Width
                  Height
                                      2    2
               Separation Surface Area, « ,  (ft )
            (1)  Separation area.
            (2)  Effluent flow.
            (3)  Overflow rate is  surface area divided by flow rate.
6"6(21.8)f}{
1.7(5.5) (1)
Total
Per Cell
Separation Volume, m3, (bbl)
Total
Oil Phase
Water Phase
Number of Cells
Flow Rate. «3/day. (bpd)
Overflow Rate Per Cell. (»3/d)/«i2,(bpd/ft2)'3'
Recycle Rate. Percent of Flow
Retention Time. min.
Average Operating Parameters
Temperature, °C(°F)
Pressure. kPag (psig)
Flow Rate. »3/d (bpd)'2'
Flow Rate. Percent of Design
Overflow Rate Per Cell. (»3/d)/m2.(bpd/ft2)
Recycle Rate. Percent of Flow
Froth Flow. Percent of Flow
7.30(78.5)
20(126)
-
-
-

49.2(121)
600(87) 600(87) 150(22)
874(5,497)
120(70)
-
-
11.2(120)
2.8(30)
6.8(43)
4
2.460(15,450)
880(515)
-
4

48.2(119)
0(0)
733(4.610)
30
260(150)
-
19
-------
                               OIL THEATER
                 FLOTATION UNIT
      FROM LP SEPARATORS
00
          SUMPS
      SETTLING TANK
      FROM SKIM PILE a
      COMPRESSOR SCRUBBER
                                             FLOTATION
                                               AID
—ao^»
                                                                     rniT)
                                                                           TO
                                                                           SEA
                               WATER     9F   9	I  9	0
                               FLOW  m3/d |4|   874    733

                                    bpd  887   5497  4610
                      Figure 76.  SS107 water handling system flow schematic.
-------
 (15,450 bpd).   The average operating flow based on effluent flow was 733 m3/d
 (4,610 bpd)  or 30 percent of design flow.  The average froth flow was 141
 m3/d  or 19 percent of the forward flow.

 SITE.SPECIFIC  TEST PROGRAM

     The planned test program for brine samples was accomplished as presented
in Table 127.  The number of samples to be taken in ten days and the time the
samples were to be taken each day are listed.

     In addition to the brine tests, the  following tests were run on crude oil
 samples:   temperature, specific gravity, viscosity, boiling range distri-
 bution, equilibration, and surface tension.

     Particle size distribution  tests were run and are reported in Section 16.

 OPERATIONAL DATA AND OBSERVATIONS

     Measurements, observations, and records  of operations are reported in
 this  subsection.

 Flow Monitoring

     The flow from the oil treater to the flotation unit was monitored con-
 tinuously as described in the subsection on  the process system.   The flo-
 tation froth was monitored the  first three days with a flow monitor and
 estimated the  remaining days.  A flotation unit effluent flow and froth
 flow  were calculated for each sample time.  These flows are reported in
 Table 128.

     The flotation unit/influent flow meter was not operational until  the
 afternoon of the first day because of orifice plate changes.   The flotation
 unit  froth flow meter failed during the  1300 sample time on Day 3.

      The water flow patterns are shown in Figure 75 and Figure 76.   The
 primary flow is the produced water from  the  wells.  The only other  signifi-
 cant flow is the flotation unit froth return to the oil treater. The froth
 was pumped back to the treater using the flotation unit launder as  a sump.
 The froth pump cycled on and off based on the liquid level  in the launder.
 The froth pump capacity was 238 m3/d (1,500  bpd).

 Well  Test Data

     The well test data provided by the operator are presented in Table 129.
 The wells are  grouped according to lift  method.

 Pressure Drops Through System

      Table 130 traces pressure  drops from the producing formation through
 the system.
                                     229
-------
OIL
TREATER
I ? Y

FLOTATION
UNIT


                          TABLE 127.  SS107 TEST SCHEDULE FOR THE MAJOR  BRINE  TESTS
ro
co
o





leld Tests
Infrared Oil
Temperature
pH
Water Specific Gravity.,.
Mater Surface Tens Ion* *'
IR-Oi) U/SilIca Gel
1R-OH Filtered Brine ,,,>
Susceptibility to Separation14'
aboratory Tests
Gravimetric 6)l
Suspended Solids
Ionic Analysis
Bacterial Culture ,.»
Particle Size Distribution14'
1 Sampling tines not shown will
2 Extra samples when IR-Oi 1 is
3 IR-Oil w/silica gel at 0. 5,
4 IR-Oil , IR-011 w/silica gel,

V
9--0
No. of Tine of
tests tests

40 8.10.13,15
10 B
10 8
10 8
10 8
20 8,13
20 8.13
-

40 8,10.13.15
10 8
1 (1)
A maximum of five
3 13
be field scheduled.
high.
and 120 Minutes.
and filtered brine tests at same time.
SAMPLE POINTS
V
9--1

V
6--0
No. of Time of No. of Tim of
tests tests tests tests

40
10
-
10
10
10
3

10
10
-
tests at sample points selected in the field.
3 13 3
NOTE: Tine of tests




8,10,13.15
a
.
8
B
8
13
tf .
8
8
-
13
listed Is by military hour.



-------
                                                            TABLE 128.   SS107 MAJOR BRINE TESTS
r\>
CO
Flotation unit
influent (9— i)
IR-011 w/silica gel
Sample time
Day Hour
01 08
01 10
01 13
01 15
02 08
02 10
02 13
02 15
03 08
03 10
03 13
03 15
04 08
04 10
04 13
04 15
05 08
OS 10
05 13
05 15
06 08
06 10
06 13
06 15
07 08
07 10
07 13
07 15
08 08
08 10
08 13
08 IS
09 08
09 10
09 13
09 15
10 08
10 10
10 13
10 15
Minimum
Maximum
GR-Oil
»9/l
197
.
.
.
137
-
.
-
171
-
-
_
120
.
.
.
126
-
-
-
248
-
-
.
184
-
-
.
163
.
-
.
139
.
-
-
183
-
-

120
248
IR-Oil
mg/1
203
389
212
212
203
186
254
195
216
195
157
127
119
212
224
250
186
203
199
195
144
135
203
186
246
229
195
203
220
220
195
237
207
229
254
254
279
254
330
237
119
389
Dispersed
mg/1
34
-
.
-
34
-
-
-
15
-
-
-
80
.
.
.
131
-
-
-
as
-
-
-
178
-
-
-
161
-
-
-
131
.
-
-
207
.
-
-
15
207
Soluble
mg/1
169
-
-
-
169
.
-
-
201
-
-
.
39
-
-
-
55
-

-
59
-
-
-
68
-
-
-
59
-
-
-
76
-
-
-
72
-
-
-
39
201
Filtered
brine
IR-011
mg/1
31
-
-
.
32
-
-
-
34
-
-
.
31
-
-
.
41
-
-
-
24
-
-
.
39
-
-
-
39
-
-
-
41
-
-
-
39
-
-
-
24
41
Surface
tension
dynes/cm
55
-
-
-
52
-
-
-
49
-
-
-
46
52
-
-
54
-
-
-
50
-
-
.
42
-
-
-
46
-
-
-
42
-
-
-
48
-
-
-
42
55
Flotation unit effluent (9—0)
IR-011 w/silica gel
GR-011
mg/1
12
15
14
101(C)
4
5
7
5
5
3
4
8
10
9
18
7
6
6
31
6
4
3
6
4
7
4
5
6
5
4
9
6
6
7
5
15
6
5
6
7
3
31
IR-011
mg/1
26
29
• 15
144(C)
15
14
15
15
14
12
12
19
11
20
17
13
16
15
14
15
11
10
14
10
15
10
14
13
14
14
16
12
14
14
14
13
14
14
14
14
10
29
Dispersed
mg/1
3
-
0
.
0
-
0
-
1
-
0
.
0
_
5
-
3
-
3
-
0
-
1
-
2
-
1
-
3
.
3
.
0
-
3
-
1
-
2
-
0
5
Soluble
23
-
15
.
15
.
15
-
13
-
12
-
11
.
12
.
13
-
11
-
11
-
13
-
13
-
13
-
11
-
13
.
14
.
n
-
13
_
12
-
11
23
Filtered
brine
IR-Oil
mg/1
25
.
30
-
28
.
30
.
30
-
31
.
32
.
32
_
31
.
33
.
37
-
27
_
30
-
32
-
32
.
35
.
33
.
33
-
34
_
34
-
25
37
Surface
tension
dynes/cm
66
.
.
4S(C)
65
.
-
-
62
.
.
_
64
.
.
_
62
.
.
-
67
-
-
_
60
.
-
-
63
_
.
•
61
_
.
.
62
_
-
-
60
67
Flow rate
Out
.
-
-
728
748
749
743
754
763
747
726
597
738
725
736
761
760
731
738
744
683
738
768
717
727
724
722
729
729
723
723
725
735
737
745
736
744
751
745
750
597
763
Sklmmlnqs
.3/d
205
102
120
101
238
210
215
222
159
156
159
159
238
141
75
68
51
61
55
48
238
238
164
223
157
161
181
193
137
143
125
123
75
83
84
91
122
115
103
98
48
238
          (C)    Not included in statistical  analysis.  The system was upset by a shutdown to Install  an orifice for survey flow monitoring
-------
                                            TABLE  129.   SS107  WELL TEST DATA
ro
u>
ro
Well Formation
9
Gas
Mcfd
Oil
EpcT
Water
lift gas
" &Y3 '
Pressure
SIBHP
, psig
FTP
Choke size
1/64 in.
API gravity
Flowing to Low Pressure Separator
11-
13-
Total (Average)
Gas lift to low Pressure
1-
6C
34
Total (Average)
Combined Total (Average)
9.752
9.720
-
Separator
10,162
9,737
9.270
-
-
198
62
260

124
71
15
210
470
265
92
357

128
64
64
256
613
1.205
292
1.497

1.470
999
16
2.485
3.982
0
0
0

344
145
286
775
775
3.980
4.200
-

4.080
4.000
3.500
-
-
160
440
-

203
106
109
-
-
open
15
-

open
open
open
-
-
35.1
35.1
(35.1)

33.0
36.7
36.2
(35.3)
(35.2)
-------
              TABLE 130.  SS107 PRESSURE DROPS THROUGH SYSTEM
Location
 Pressure,
   kPag
  (psig)
    Pressure drop,
point or description
Pressure drop,
   kPag
  (psig)
Formation
(SIBHP)
Flowing Tubing
Pressure
Low Pressure
Separator
Oil Treater
24,100-29,000
(3,500-4,200)
   730-3,030
  (106-440)
   531-696
   (77-101)
   140-170
   (20-25)
    perforations,
    static head,
    pipes
    chokes,
    valves,
    pipes
    control  valve,
    pipes
                                       control valve,
                                       orifice plate,
                                       pipes
23,400-26,800
(3,390-3,890)
   130-2,430
   (19-353)
   381-546
   (55-79)
                              140-170
                              (20-25)
Flotation Unit
     Table 130 shows that the greatest pressure drops occur from the forma-
tion to the chokes, substantial drops occur at the chokes, and more minor
drops from the chokes on.

Chemical Addition

     Four chemicals were added by metering pumps.  Chemical usage was monitor-
ed daily by noting the volume of chemical remaining in the feed pump reser-
voir.

     A flotation aid, Tretolite FR 98D, was added about one meter upstream of
the flotation unit.  The addition rate was not uniform.  An addition rate for
each day is presented in Table 131.

     The usage of other chemicals is shown in Table 132.

Observations and Operator Reports

     An effort was made to record any event that could affect effluent oil
content.  The operators were requested to provide information on upsets and
intermittent operational or maintenance procedures and the survey team made
their own observations.
                                      233
-------
               TABLE 131.   SS107  FLOTATION  CHEMICAL  ADDITION

Day
01
02
03
04
05
06
07
08
09
10
Mean
Addition
dmVd
7.4
5.1
4.5
5.6
7.5
-
17.1
18.6
19.0
8.6
10
rate
pprmr
10.2
6.9
6.4
7.6
10.1
-
23.6
25.7
25.7
11.4
14

(1)  Based on average water flow through the flotation unit for each day.
                     TABLE  132.  SS107  CHEMICAL ADDITION
Chemical
Methanol
MUU 1 U 1 Ufl
point
Lift gas
dmVd
8.0^
ppmv
—
Tretolite RN3003          Well Manifold                8.6      8.9^
(Demulsifier)             ahead of 5A2
                                                                   (2}
Tretolite SP175           Low Pressure                 7.3      7.V
(Scale inhibitor)         separator outlet

(1)  Stopped injecting methanol on Day 9.
(2)  Based on average fluid flow through the oil treater.

     After the 1300 sample time on Day 1, the level in the oil treater was
lowered in preparation for changing the orifice plate between the oil treater
and the flotation unit.  The flow to the flotation unit was stopped for about
45 minutes after the liquid level  in the oil treater was lowered.  The flow
to the flotation unit was resumed an hour before the 1500 samples were taken.

     The flow to the flotation unit was stopped for about 10 minutes after
the 0800 sample time on Day 3.  The flow was stopped to allow a leak in the
line to be repaired.

                                     234
-------
     The froth flow meter failed on Day 3 during the 1300 sample period.  The
flow meter was a positive displacement meter and the failure blocked the
line.  The recycle of the froth to the oil treater was resumed at 1615 on
Day 3.

     All wells except Well 34 shut in during the 0800 sample period on Day 6.
Wells 6c, 11 and 13 were shut in for 15-20 minutes.  Well 34 was shut in for
1-li hours.

     The only rain was on Day 6 at 1630.  Deck washings took place on Day 6
and 7.  The effect of rain, deck washings, and settlement tank bottoms is not
known because these liquids were pumped into the system at night.  A few
cubic meters of oil and water was pumped off the skim sump on nights 7 and 9.
On night 9, a few cubic meters of liquid was pumped off the skim pile and
about 20 cubic meters of liquid off the settlement tank bottom.

DATA PRESENTATION AND EVALUATION

     Comprehensive data tables, summary tables and graphs for SS107 are
interspersed in the text.

Effluent Oil Content

     Table 128 presents a listing of oil content test results for the major
sampling points.  Figure 77 presents a plot of GR-Oil in and out of the
flotation unit versus time.  Figure 78 presents the same plot for IR-Oil
content.  The time-indexed plots are based on four test results per day,
except for the flotation unit influent GR-Oil.

     The tabulated data and time-indexed plots show that the flotation unit
influent is relatively uniform with only two of the 40 IR-Oil contents over
300 mg/1.  The flotation unit effluent oil content is exceptionally uniform
except for Day 1 at 1500.  The high oil content at 1500 followed the changing
of the orifice plate in the flow meter monitoring the oil treater effluent
water flow.  The oil treater liquid level had been lowered and the flow to
the flotation unit had been stopped prior to changing the orifice plate.
Although the 1500 flotation unit influent IR-Oil does not indicate that the
oil treater is upset, it is believed that the flotation unit had not yet
recovered.

     The ranges of test results, not including Day 1 at 1500, are as follows:

     Flotation Effluent GR-Oil - 3 to 31 mg/1,
     Flotation Effluent IR-Oil - 10 to 29 mg/1,
     Flotation Influent GR-Oil - 120 to 248 mg/1,
     Flotation Influent IR-Oil - 119 to 389 mg/1.

     Flotation unit effluent oil content histograms for the two test methods
are presented in Figure 79 and Figure 80.  Figure 81 is a regression plot of
effluent GR-Oil versus IR-Oil.  In comparing oil content test results by the
two methods, it should be remembered that the samples were taken about one
minute apart from a flowing stream.  Therefore, the comparisons include

                                     235
-------
 01    ,    6
                        SA
                         I	*    I
              I    k    I
                                                                                          -O
                                                                                          -001
                                                                                           •ooz   l/Bui
                                                                                                110-MI
                                                                                          1-006
                                                                                           •OO*
                                                                                                            n
01
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  8
q.j.un
                                          AVO
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                                                                                                110-89
-------
FREQUENCY
    %
              60-
             50-
              40-
              30-
              20-
                                             ns 39
                                             x= 7.6
                                             »= 5.2
                                                                1
                                                               50
                  10        20        30        40
                                GR-OIL,mg/I
Figure 79.  SS107 flotation unit effluent,  GR-oil  histogram.
FREQUENCY
    %
              50-
              50-
              30-
              20-J
                                               39
                                               15
                          10
                                               I
                           20        30        40
                                IR-OIL, mq/l
I
50
        Figure  80.   SS107  flotation unit effluent, IR-oil histogram.
                                   237
-------
'UOISS9J63J
                               jiun
                                                                ZOISS  '18
      09
1      1
OS
                          Ofr
OC
O2
01
                                                        IfO
 1      1      1      1      1      1     1      1     1     .l
                                                                                 01
                                                                                 02
                                                                                 OC
                                                                                 Ofr
                                                                                 OS
                                                                                       1IO-M0
                                                                                   n
                                                                                   OJ
-------
time dependent sample differences as well as normal sampling and testing
variations.

     Table 133 presents a summary comparison of test results by the two
methods.

                TABLE 133.  SS107 FLOTATION UNIT EFFLUENT
	GR-OIL AND IR-OIL COMPARISON	.

                                           Oil content
                                        GR-Oii     IR-Oi
Number of tests, (n)                      39         39
Mean, (x), mg/1                            8         15
Minimum, mg/T                              3         10
Maximum, mg/1                             31         29
Standard Deviation,(s), mg/1               5.2        3.7

                                           Paired tests
Number, (n)           _                         39
Mean of Differences, (A), mg/1                   8.1
Standard Deviation, (sj, mg/1                   3.3
     The data presented in Table 133 and the histograms indicate that the
mean oil content is higher by the IR-Oi1 test method than by the GR-Oil test
method.  However, the scatter of the data in the regression plot, Figure 81
and the correlation coefficient of 0.37 indicate only limited correlation.

     All test results for dispersed oil and soluble oil as measured by the
IR-Oi1 w/Silica Gel test are listed in Table 128.  -A summary of these test
results on the flotation unit effluent is presented in Table 134.

	TABLE  134.   SS1Q7  SOLUBLE  OIL SUMMARY	

                              Flotation effluent             Proportion
                            Range             Mean            of total,
Analysis or test            mg/1              mg/1             percent

IR-Oi1                      11-26             14.8               100
Dispersed Oil                0-5               1.6                11
Soluble Oil                 11-23             13.2                89


Note:  Table includes only IR-Oil tests when an IR-Oil w/Silica Gel test
       was run.


     An average of 89 percent of the oil  in the effluent was soluble oil  and
11 percent was dispersed oil.

                                     239
-------
     Linear regression plots of dispersed oil versus IR-Oil and GR-Oil are
presented in Figure 82.  Extrapolations of the linear regression lines to
zero dispersed oil indicate a residual IR-Oil of 13 mg/1 and a residual GR-Oil
of 6 mg/1 after all dispersed oil is removed.  The mean soluble oil content of
the flotation unit effluent was 13 mg/1.

     The mean soluble oil content of the flotation unit influent was 97 mg/1,
which is significantly higher than the mean of 13 mg/1  of the flotation unit
effluent.

Surface Tension

     All surface tension test results are listed in Table 128.  The mean
surface tension of the flotation influent is 49 dynes/cm and of the flotation
effluent is 63 dynes/cm.  The range for flotation effluent test results was
from 60 to 67 dynes/cm not including the Day 1, 1500 sample.  The linear
regression equation for effluent IR-Oil and surface tension is:

              IR-Oil  » 403-6.1 (Surface Tension)
                   r = -0.92

     The test result on Day 1 at 1500 after the orifice plate was changed was
included in calculating the regression equation.  A decrease in IR-Oil content
of 6.1 mg/1 is indicated for each 1 dyne/cm increase in surface tension.

Suspended Solids

     The suspended solids tests were run on the flotation unit influent and
effluent.  Total suspended solids and Freon soluble suspended solids data
were not obtained because of problems in completing the analyses.  The data
obtained are recorded in Table 135 and a suspended solids summary for SS107
is presented in Table 136.

     The data in Table 136 indicate that all of the solids were acid soluble.
The average suspended solids reduction across the flotation unit was 60 per-
cent.

     Figure 83 presents time-indexed plots of Freon insoluble suspended solids
in the flotation unit influent and effluent, and of flotation effluent dis-
persed oil.  All samples were taken at the same time, 0800 each day.  The
plotted data do not demonstrate a distinct pattern that the dispersed oil con-
tent of the effluent is higher when suspended solids are higher in the flota-
tion unit influent or effluent.  As discussed in Section 18, the suspended
solids test method may not have sufficient precision to provide meaningful
results at the solids concentration in the SS107 brine.

Filtered Brine

     The filtered brine IR-Oil content of SS107 effluent was in the range of
15 to 37 mg/1 with a mean of 31 mg/1.  The mean effluent IR-Oil content of
unfiltered brine on SS107 was 15 mg/1 for samples when  filtered brine tests
were also run.  The fact that the measured oil  content  of filtered brine was

                                      240
-------
        33
                                 • TOTAL IR-OIL VS DISPERSED  IR-OIL
                                  TOTAL IR-OIL * 13+0.97 (DISPERSED  IR-OIL)
                                             r - 0.48
        30
        23
TOTAL
  OIL
 mg/1
20
         15
         10
                   TOTAL IR-OIL- DISPERSED  IR-OIL
                                            TOTAL GR-OIL-
                                            OISPERSEO  IR-OIL
                    • TOTAL QR-OIL  VS   DISPERSED  IR-OIL
                      TOTAL SR-OIL  • 5.7 -t- 1.3 ( DISPERSED IR-OIL)
                                 r  « 0.43
                                  DISPERSED  IR-OIL,mg/1
                Figure 82.   SS107 flotation unit effluent,
                  total oil  - dispersed  oil  regression.
                                     241
-------
                   TABLE  135.   SS107 SUSPENDED  SOLIDS TESTS
                   notation unit. In (3—i)
                                            Flotation unit, out (9—0)
                   FreonFreon    Add               FreonFreon     Add
   Sample time  Total   soluble  Insoluble   soluble  Fixed   Totsl  soluble  Insoluble  soluble  Fixed
   13ayHour  mg/l    mg/1      mg/1     ing/1   ig/1   mg/T    mg/1     mg/1    "TngTlmg/T
   01
   02
   03
   04
   OS
   06
   07
   08
   09
   10
08
08
08
08
08
03
08
08
08
08
   Maximum
 8
17
22
18
13
15
23
11
 7
11

 7
23
 3
17
22
18
13
IS
23
11
 7
11

 7
23
 5
 S
 7
10
 7
 4
 1
 7
 9
 8

 1
10
 5
 6
 7
10
 7
 4
 0
 7
 9
 3

 0
10
                 TABLE 136.   SS107 SUSPENDED  SOLIDS SUMMARY
Suspended Solids
                             Average suspended  solids, mg/1
                                  9~i9--0
Freon Insoluble
Acid Soluble
Fixed
15
15
0
6
• 6
0

consistently higher than that  for unfiltered brine  indicates a bias  to the
high side  for the filtered brine tests run on SS107  effluent.

     The filtered brine mean IR-Oil  content of the  flotation influent  was 35
mg/1, which  was very close to  the mean effluent filtered brine oil content.

Flotation  Unit Performance

     Figure  84 is a regression plot  of IR-Oil in  and out of the flotation
unit.  The slope of the linear regression line is only 0.03 indicating little
or no effect of influent oil on effluent oil.

     Figure  85 is a regression plot  of flotation  unit effluent IR-Oil  con-
tent and percent hydraulic loading.   A similar plot  for the gravity  separator
effluent is  also presented.  The slope of the linear regression line is -0.39,
indicating a slight negative relationship between hydraulic loading  and
effluent oil.

     The lack of expected relationships between effluent oil and  influent oil
or hydraulic loading may be because  of the stable influent oil (119  mg/1  to
                                       242
-------
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                              '£8
AVQ
                                                               CvJ
-------
               I   I  I  I  I
                    III!
  |  I  I  I  I  |  I   I  I  I  |  I  I  I   1  |  I  f  I  I  |  I  I  I  I  |
                           1  I  I
          so
                                                               IR-OIL ou!»8.HhO.O3O(IH-OlL In)

                                                                      r >O.4I
ro
          40
       O
        i
       tc
          30
u.
UJ
          20
       g
       u.
          10
               1  1  1
               1  I  1  1  1  1  1  1  t   1  1   1  1  1  1  1   1
                             1  1  1  1    1   1  1
1  1  1  1   1  t
1   1  1  1    1  1  1
                        50
                             100
                                                                                    300
              ISO         200          250


         FLOTATION UNIT INFLUENT IR-0!L,mg/l


Figure 84.  SS107  flotation unit in-out IR-oil regression.
                                                                                         350
-------
IN)
4*
Ol
                     50-
                     40-
FLOTATION

    UNIT

 EFFLUENT
          IR-OIL
           mg/l
                     30-
              20-
                     10-
                                        i  I  T
                                               T  I   I  I   I  |  |  I  I   I  I   I  I  I   I  I   I
                                                       IR-OIL* 26 -0.39(HYDRAULIC LOADING)
                                                           r • -0.21
                                                                                              •«•*••••
                                                                                               ••  •
                                                                                              ••  •
                   I   I  I  I   I  I  1  I  I   I  I   I  I  I  I  I   I  I  I  I  I
                             5           10           15           20
                                                                                 I   I  I   I  I  I  I  I   I  I
                                                                                    25          30
                                                        HYDRAULIC  LOADING, %

                   Figure 85.   SS107  flotation  unit hydraulic loading - infrared oil  regression.
-------
389 mg/1) and the moderately low hydraulic loading.  The hydraulic loading
was in the range of 24 to 31 percent of the design capacity.

Oil Treater Performance

     The sample point for the oil treater effluent is the same as for the
flotation unit influent (9~i).  The treater effluent oil content data are
presented in Table 128.  The treater effluent mean IR-Oil content was 215
mg/1.

     The results of the susceptibility to separation tests on the treater
effluent are presented in Table 137.  The mean IR-Oil content after 15 minutes
of settling was 103 mg/1.  If the 103 mg/1 is compared to the treater effluent
mean IR-Oil of 215 mg/1, it indicates that additional oil could be removed
by static settling.

     The largest oil drop measured by the particle size test in the oil
treater effluent had a diameter of 35 um.

Miscellaneous Brine Tests

     All other brine test results for SS107 are listed in Tables 138, 139, and
140.  The results for the following tests were generally in narrow ranges for
all samples:  temperature, pH, and specific gravity.  These parameters were
therefore not examined for correlation with sample-to-sample variation in
effluent oil content.  These parameters will be discussed in a later section
with respect to variations between platforms.

     Only one ionic analysis test and one sulfate reducing bacteria test per
sample point were run on SS107.  These tests also are only significant with
respect to comparisons between platforms.

Crude Oil Tests

     All crude oil test results are listed in Tables 141 and 142.  The crude
oil temperature, specific gravity, and surface tension test results all  fell
in narrow ranges with the exception of one temperature reading.

     The viscosity and boiling range distribution tests were limited in
number to one and are of primary significance for comparisons between plat-
forms.  Two equilibration tests were run, each at a different oil/water ratio.

     The limited number of tests run on crude oil provide only a limited
characterization of the crude oil.  Between-platform comparisons will be
presented in Section 17.
                                     246
-------
	TABLE  137.  SS107 SUSCEPTIBILITY TO SEPARATION TESTS OIL TREATER  EFFLUENT	

                               	Settling times, minutes	

                                  0         2        5       15      30      60      120       0


Test Number 1
Day 4, 1000	
IR-011, mg/1                     212       127      127     110      89      47      127        254
IR-011 W/Sillca Gel, mg/1        153        -        76      -       -       -       64


Test Number 2
Day 6, 1000
IR-011, mg/1                     136       102       93      85      76      63       56        153
IR-011 W/Sillca Gel, mg/1         68        -        34      -       -       -        40


Test Number 3
Day 8. 1000	
IR-Oil, mg/1                     220       127      136     114     102      85       75        237
IR-011 W/Silica Gel, mg/1        170        -        85      -       -       -        60


Average

IR-011, mg/1                     189       119      119     103      89      65       86        215
IR-011 W/Sillca Gel, mg/1         130        -        65      -       -       -        55
-------
           TABLE 138.  SS107 SUPPLEMENTARY  BRINE  TESTS
Sample tire
Day Hour
01 08
02 08
03 08
04 08
05 08
06 08
07 08
08 08
09 08
10 08
Mean
Minimum
Maximum
Temperature
9— i
40.5
49.5
49.0
49.5
51.0
52.0
52.0
50.0
48.0
50.0
49.2
40.5
52.0
, °c
9—0
39.0
48.0
49.5
50.5
50.0
51.0
51.0
49.0
46.5
47.0
48.2
39.0
51.0
_RH_
9—0
6.7
6.5
6.3
6.9
6.7
6.8
6.8
6.4
6.8
- 6.5
6.6
6.3
6.9
Specific^
gravity
9—0
1.099
1.089
1.089
1.094
1.099
1.093
1.094
1.099
1.094
1.099
1.095
1.089
1.099
Note:   Sample  point  identification numbers (9—i, 9—0) as shown
       on flow diagrams.

(1)    Specific gravity  is reported at temperature shown in table
       above.
                               248
-------
      TABLE 139.  SS107 IONIC ANALYSIS FLOTATION UNIT EFFLUENT

Constituent                                 Concentration, mg/1
Sodium (Na)                                       40,000
Potassium (K)                                         340
Calcium (Ca)                                       3,500
Magnesium (Mg)                                       740
Barium (Ba)                                          198
Chloride (Cl)                                      61,600
Sulfate (SOd)                                           5
Alkalinity (as HC03)                                 464
Iron (Total)                                           9
Sulfide (as H2S)                                       0.14

Total Dissolved Solids
     Summation                                    106,000
     Gravimetric                                  112,000

Sample Day and Hour:  09 at 13
         TABLE 140.  SS107 SULFATE KtuuuNG BACTERIA
Sample point                          Bacteria  per milliliter
Oil Treater - Out (6—0)                        0
Flotation Unit - Out (9—0)                     0

Sample Day and Hour:  07 at 13
                                249
-------
           TABLE 141.  SS107 CRUDE OIL MISCELLANEOUS TESTS
                                                          (1)

Sample time
Day Hour
01 08
02 ~ 08
03 08
04 08
05 08
06 08
07 08
08 08
09 08
10 08
Mean
Minimum
Maximum
Temperature
_^_
38.5
42.5
44.0
44.5
48.0
45.5
47.0
45.0
44.0
46.0
44.5
38.5
48.0
Specific^
gravity
0.838
0.825
0.822
0.824
0.821
0.822
0.824
0.824
0.825
0.824
0.825
0.821
0.838
Surface tension;1 '
dynes /cm
27
26
26
25
26
26
26
27
27
27
26
25
27
Sample time
Day    Hour
09
13
                          Viscosity at 37.77°C
 Kinematic
centistokes

   4.34
 Absolute
centipoise

   3.71
                          Equilibration at 82°C
                       Brine TDS = 106,000 mg/1
Oil/Water Ratio              4/1
IR-Oil, mg/1                  12
IR-Oil W/Silica Gel, mg/1      8
IR-Oil Filtered Brine, mg/1   12
                                   0.15/1
                                    14
                                     2
                                     8
(1)  Samples taken from oil treater.
(2)  Specific gravity reported for temperature in table.
(3)  Surface tension measured and reported at ambient temperatures
     from 19.0° to 24.0°C.
                                 250
-------
           TABLE 142.  SS107 CRUDE OIL BOILING RANGE DISTRIBUTION
Initial Boiling Point, °C
Final Boiling Point, °C

Boiling range, °C

Below - 200
  200 - 250
  250 - 300
  300 - 350
  350 - 400
  400 - 450
  450 - 500

Total
       Run

       150
       500

Percent recovered

       38.2
       24.3
       25.5
        6.3
        3.0
        2.0
        0.7

      100.0
                                     251
-------
                                 SECTION 13

                               PLATFORM  SS198G
GENERAL
     The ten-day testing survey was conducted on Platform SS198G from March 17
through March 26, 1980.

     A description of the production facilities, the test program, and data
presentation and evaluation are presented in this section.

     Four survey team members arrived at the platform on March 16 and the test
equipment was set up the same day.  Oil company personnel unloaded the equip-
ment and provided living quarters, work space, sample taps, and the utilities
needed to conduct the Program.

     The complete testing survey was carried out without interruption by
weather, operating problems, or for any other reason.

FACILITIES AND OPERATIONS

Production From Wells

     Five wells were producing.  Only one of the wells was an oil well.  It
flowed to the low-pressure gas-liquid separator.  The other four wells were
high-pressure gas wells which flowed to the high-pressure separator.   The liq-
uid from the high-pressure separator was manually drained to the low-pressure
separator once or twice per week.

     Three gas lift wells were shut in because the low-pressure gas compressor
went down two days before the survey team arrived.  Only minor interruptions
in production occurred during the ten-day test survey.

     The average daily production calculated from well test data was  94 m3/d
(593 bpd) of oil, 31 m3/d (195 bpd) of water, and 405,000 std m3/d (14,320
Mcfd) of gas.  The calculated water cut based on this data was 25 percent.

     The measured oil production for the ten-day period averaged 99 m3/d (623
bpd) or 5 percent more than the well test data.   The water production was
estimated at 11.8 m3/d (74 bpd) or 62 percent less than the well  test data.

Production Process System

     The flow of oil and water through the system is shown in Figure  86.

                                      252
-------
                     
-------
Design and operating data on major vessels are presented in Table 143.   The
oil/water/gas flow is from the well  to the low-pressure gas-liquid separator.

     A demulsifier, Tretolite RP2327, and a scale inhibitor, Tretolite SP246,
are added to the produced fluids at the well  manifold ahead of the low-
pressure separator.

     The fluids flow from the low-pressure separator to the electrostatic oil
treater.  Oil flows from the treater to the storage tank.   The water flows
from the oil treater to the corrugated plate interceptor (CPI).

     Figure 87 is a flow schematic for the water treating system.  The water
flows from the CPI through two flotation units operating in series, and then
to discharge.  Platform SS198G was the only platform in this survey with two
flotation units.  In order for SS198G to be comparable to the rest of the
platforms, the effluent from the first flotation unit is considered the plat-
form effluent.

     Skimmings from the CPI and flotation units were pumped to the oil  treater
on Days 1 through 4 and part of Day 10.  The rest of the time the skimmings
were pumped to the oil  storage tank.

     The water which settled out in the oil storage tank was periodically
drained to the skim sump.  Miscellaneous other drains discharge to skim sumps,
and any oil recovered is pumped to the line with the skimmings.  Drip pans
under rotating equipment and the LACT unit drains to the waste oil sump which
pumps into the skimmings line.  The flare scrubber and the fuel gas scrubber
also discharge to this  line.

     The flow from the  oil treater to the CPI was monitored continuously as
described in the subsection on flow monitoring.  The flows in Figure 87
were developed using this flow meter and the estimating procedures also de-
scribed in the flow monitoring subsection.  The average flow rates reported
in Figure 87 are divided according to where the skimmings are pumped.  When
the skimmings were pumped to the oil storage tank they were not recycled.
Any water drained from  the oil storage tank flowed to the skim sump and was
then discharged.

     A water treating chemical, Tretolite FR88, was added to the flotation
unit influent.  The addition rate varied from 0 to 4.6 dm3/d (1.2 gpd).

     The CPI unit is a  gravity separator of proprietary design supplied by
Monarch Separators, Inc.  Oil separates as the water flows between parallel
plates spaced approximately 2 cm (0.75 in.) apart.  Figure 44 is a undimen-
sioned representational sketch of a CPI unit.

     The CPI unit on SS198G is a one-pack unit.  The approximate dimensions of
the pack are 1 m high,  1 m wide, and 1.75 m long.  Based on the manufacturer's
recommended sizing procedure and the conditions prevailing on SS198G during
the survey, the CPI on  SS198G should accomplish the separation of 40-micron
oil drops at flow rates up to 870 m3/d (5,500 bpd).  Average hydraulic  load-
ing was estimated to be 10.2 m3/d (64 bpd), or 1.2 percent of design.

                                      254
-------
                                      TABLE 143.   SS198G VESSEL DATA SHEET
en
cn

5A3
Low pressure
2-phase
Vessel description separator
Trade Name or Vessel Type Horizontal
Cylinder
teslgn Parameters
Dimensions, n, (ft)
Diameter. O.D. 0.91(3)
Length. S.S. 3.05(10)
Length
Width
Height
Separation Surface Area. a2, (ft2)
Total
Per Cell
Separation Volume, n3, (bbl)
Total
Oil Phase
Water Phase
Number of Cells
Flow Rate. n3/day. (bpd)
Overflow Rate Per Cell. (m3/d)/H2.(bpd/ft2)(5)
Recycle Rate, Percent of Flow
Retention Time, nin.
Average Operating Parameters
Temperature. °C(°F)
Pressure. kPag (psig) 640(93)
Flow Rate. m3/d (bpd)'4*
Flow Rate. Percent of Design
Overflow Rate Per Cell. (m3/d)/m2.(bpd/ft2)
Recycle Rate, Percent of Flow
Froth Flow, Percent of Flow
1) Proprietary unit with one plate pack.
2 Based on removing 40-pin oil drops.
3 i Separation area.
4 Effluent flow.
5 Overflow rate is surface area divided by flow rate.
VESSEL DESIGNATION
6
Oil treater,
chem
electric
Horizontal
Cylinder


2.44(8)
4.57(15)
-

.
-

-
-
-
_
286(1.800)
-
-
-

36.5(98)
440(64)
15.6(98)
-
-
-
-





ON FLOW DIAGRAM - FIGURE 13-1
8 9-1
Gravity Flotation unit
separator, hydraulic
CPI dispersed gas
Monarch'1' Trldalr
Model DC500


_
3.20(10.5)i3{
1.07(3.5) (3)
.

3.42(36.8)
1.14(12.3)

2.8(18)
-
-
3
870(5. 500)(2) 795(5.000)
700(410)
450
5

33.4(92) 31.1(88)
0(0) 0(0)
10.2(64) 9.2(58)
1.2
8.1(4.7)
39.000
11






9-2
, Flotation unit,
hydraulic
dispersed gas
Monosep
Model AG-3000


.
2.59(8.5)
1.52(5)
-

3.07(33)
.

5.1(32)

-
.
490(3,100)
160(94)
400
15

-
0(0)
8.9(56)
1.8
2.9(1.7)
22.000
3





-------
                CPI  GRAVITY
                 SEPARATOR
                                  FLOTATION  UNITS
                                 FLOTATION
ro
en
                                    AID
      QHD
            -*•
       FROM
       OIL
       THEATER
kn
             TO
         OIL TREATER
             OR
         OIL STORAGE
                      (  *'  )
                                       TO
                                   OIL TREATER
                                       OR
                                   OIL STORAGE
WATER FLOW
SKIMMINGS TO
OIL TREATER
SKIMMINGS TO
OIL STORAGE
8 F
m 3/d 7. 2
bpd 45
m3/d 4
bpd 25
a__l
19. 6
123
12.4
78
9FI
1
6
1
6
9_II
12.4
78
8.4
53
9
M
7
_ IO
. 4
2
7.4
4
7
9F2
0.3
2
0.3
2
9_
II .
70
7.1
45
20
1



                           Figure 87.  SS198G water handling system flow schematic.
-------
     The first flotation unit, a Tridair (Model DC500), is a proprietary
three-cell dispersed gas unit similar to the four-cell unit depicted in Figure
32.  Gas for flotation is educted hydraulically.  Oil separation is by skim-
ming froth over a side weir in each section.

     The design flow for the unit is 795 m3/d  (5,000 bpd).  The average opera-
ting flow based on effluent flow was 9.2 m3/d  (58 bpd) or 1.2 percent of
design flow.  The froth flow was 1 m3/d (6 bpd) or 11 percent of forward flow.
The recycle flow was 3,590 m3/d (22,600 bpd).

     The second flotation unit, a Monosep (Model AG-3000), is a proprietary
one-cell dispersed gas unit.  The unit is depicted in Figure 19 and the
dimensions are in Table 143.  Gas for flotation is educted hydraulically.
Froth is removed over a single weir at the outlet end.  The recycle water
flow for gas dispersion is 400 percent of the design forward flow.

     The design flow for the unit is 490 m3/d  (3,100 bpd).  The average opera-
ting flow rate was 8.9 m3/d (56 bpd), based on effluent flow or 1.8 percent
of design flow.  The average froth flow was 0.3 m3/d (2 bpd) or 3 percent of
the forward flow.

SITE SPECIFIC TEST PROGRAM

     The planned test program for brine samples was accomplished as presented
in Table 144 with one exception.  The ten GR-Oil tests that were to be per-
formed at 9-li were inadvertently taken at 8—i.  The number of samples to be
taken in ten days and the time the samples were to be taken each day are
listed in Table 144.  For this survey sample point 9-10 is considered the
platform effluent, and for that reason the bulk of the tests were performed
on samples from 9-10 and not 9-20.

     In addition to the brine tests, the following tests were run on crude
oil samples:  temperature, specific gravity, viscosity, boiling range distri-
bution, equilibration, and surface tension.

     Particle size distribution tests were run and are reported in Section 16.

OPERATIONAL DATA AND OBSERVATIONS

     Measurements, observations, and records of operations are reported in
this subsection.

Flow Monitoring

     The water flow patterns are shown in Figure 86 and Figure 87.   The pri-
mary flow is the produced water from the wells.  The only  other significant
flow is the CPI skimmings.

     The flow from the oil treater to the CPI was monitored continuously with
a positive-displacement type flow meter.  The skimmings flows were estimated
four times daily based on manufacturer's pump data on volume per stroke.  The
Tridair froth flow was estimated at 1 m3/d based on the visual  observation of

                                      257
-------
OIL
THEATER

	 I „ ^p
GRAVITY
SEPARATOR


FLOTATION
UNIT
>_,

FLOTATION
UNIT


                                   TABLE 144.   SS198G  TEST SCHEDULE FOR THE  MAJOR  BRINE  TESTS
                                                                                            SAMPLE POINTS
                                                          9-20
                                                     Ho.  of
                                                      tests
                        Time of
                         tests
NbT^r
 tests
                                                 2
                                                V

                                                9-21
"Time of
  tests
                                                 V
                                                9-11
                                                                                                                                       8--1
                                           No. of
                                           tests
                                time of
                                 tests
                                         No.  of
                                         tests
                               Time of
                                tests
00
         Field Tests
           Infrared Oil
           Temperature
           pH
           Uater Specific Gravity..
           Water Surface Tension1 '
           IR-011 U/Silica Gel
           IR-Oil Filtered Brine
           Susceptibility to Separation'

         Laboratory Tests
           Gravimetric Oil
           Suspended Solids
           Ionic Analysis
           Bacterial Culture
           Particle Size Distribution
                  20
                  10
8.13
  8
(3)
20
10
10
10
10
20
20
8.13
  8
  8
  8
  8
8,13
8,13
20
10
                                   8.13
                                     8
                                            40   8.10,13.15           10        8
                  10        8                10       8               10        8
                                             1       (1)               -        -
                  A maximum of five  tests at sample points selected in  the field.
                  3       13                 -       -                3       13
                                            20
                                            10
                                                                     10
                                                                     10
                                                                     10
                                                                      3
                                                                     10


                                                                      3
8.13
  8
                                  8
                                  8
                                  8
                                 13
                                                            8


                                                           13
          (1)  Sampling times not shown will be field scheduled.
          (2)  Extra samples when IR-Oil Is high.
          (3)  IR-Oil w/Silica Gel at 0. 5, and 120 minutes.
          (4)  IR-011, IR-Oil w/Silica Gel. and filtered brine tests at same time.
                                                                NOTE:  Time of tests listed is by military hour.
-------
the flexible paddles wiping a minimal amount of liquid over the weir and into
the launder.  Using this flow information a Tridair effluent and skimmings
flow rate were estimated for each sample period.  These flows are recorded
in Table 145.

     The produced water flow rate indicated in Figure 87 is less than half
the rate shown in the last test of Well G5 on March 1, 1980.  The produced
water rate ranged from 21 bpd to 275 bpd in the seven tests of Well G5 over
the previous eight months.  A total of three water cuts were run on the fluid
from Well G5 in an effort to explain the discrepancy between the well test
data and the flow meter.  These water cuts ranged from 6 to 30 percent.  This
information shows that the amount of water produced by Well G5 is highly
variable and the flow meter information is assumed to be correct.

Wei] Test Data

     The well test data provided by the operator are presented in Table 146.
The wells are grouped according to whether the flow was to the high-pressure
or low-pressure separator.

Pressure Drops Through System

     Table 147 traces pressure drops from the wellhead through the system.
The table includes only the well producing water.

     The table shows that substantial pressure drops occur at the chokes and
more minor drops from the chokes on.

Chemical Addition

     Three chemicals were added by metering pumps.  Chemical usage was
monitored daily by noting the volume of chemical  remaining in the feed pump
reservoir.

     A flotation aid, Tretolite FR88, was added about one meter upstream of
the flotation unit.  The 9-li sample was taken at the same point.  The addi-
tion rate was not uniform.  An addition rate for each day is presented in
Table 148.

     The flotation aid chemical  feedpump was operating on Days 2 and 3 but
there was not a measurable change in the liquid level  in the chemical
reservoir.  The operator adjusted the feed rate the evening of Day 3.

     Samples were taken at 9-li  at 0800 and 1300.  Before taking a sample at
9-li, the injection of flotation aid chemical  was stopped by closing a valve.
On Day 10 the valve was already closed when the survey team went to take the
0800 sample.  The valve was probably left closed after taking the 1300 sample
on Day 9.

     The CPI is batch treated once per month with 19 dm3 of scale inhibitor,
Tretolite SP 36.  This treatment was performed on Day 7 at the beginning of
the 0800 sample period.  The chemical was dumped on the inlet of the CPI.

                                     259
-------
                                                      TABLE  145.   SS198G MAJOR  BRINE TESTS
ro
Gravity separator influent (a— 1)
Sample tine
Day
01
01
01
01
02
02
02
02
03
03
03
03
04
04
04
04
05
05
OS
05
06
06
06
06
07
07
07
07
08
08
08
08
09
09
09
09
10
10
10
10
Minim
Haxim
Hour
08
10
13
IS
08
10
13
15
08
10
13
IS
08
10
13
15
08
10
13
15
06
10
13
15
06
10
13
15
06
10
13
IS
08
10
13
15
OB
10
13
IS
M
urn
GR-Oil
Mg/1
186

.
.
208
-
.
-
21S
-
.
-
299
-
-
-
170
-
.
-
180
-
.
-
145
-
-
-
160
-
-
-
144
-
-
-
157
-
-

144
299
IR-011
283
-
237
-
262
-
237
-
313
-
237
-
507
-
406
-
203
-
186
-
220
-
224
-
182
-
199
-
224
-
245
-
207
-
232
"
220
-
330
-
182
507
1R-011 w/silica gel
Dispersed. Soluble
•g/1 »9/l
224
-
-
-
190
-
-
-
211
-
-
-
406
-
-
-
127
-
-
~
131
-
-
-
114
-
-
-
135
-
-
~
60
"
-
~
169
-
-
-
80
406
59
-
-
-
72
-
-
-
102
-
-
-
101
-
-
-
76
-
-
-
89
-
-
-
68
-
-
-
89
-
-
-
127
~
-
~
51
-
-
-
SI
127
Filtered
brine
IR-011
«8/l
83
-
-
-
83
-
-
-
125
-
-
-
84
-
-
-
76
-
-
•
80
-
-
-
81
•
-
-
79
-
-
—
76
*
-
*
97
-
-
-
76
125
Surface
.tension
dynes/a
35
.
-
-
36
-
.
-
34
.
.
-
36
.
.
-
34
-
-
-
27
.
-
-
33
.
.
-
31
-
-
-
33
-
-
-
31
-
-
-
27
36
(9-11)
IR-011
D mg/1
127
-
135
-
114
-
118
~
127
-
110
-
203
-
253
"
114
~
89
"
144
~
106
•
110
™
114
*
118
"
110
~
114
~
106
~
110
~
177
-
89
253
GR-011
*>9/l
28
18
10
19
34
45
34
24
18
17
13
19
.21
23
30
33
16
15
20
14
19
18
16
14
247(B)
9
9
9
22
22
27
11
2
3
5
11
47(C)
25
14
10
2
45
IR-Oil
my /I
30
-
30
-
50
-
S3
-
34
-
34
-
42
.
47
-
32
-
31
-
10
-
31
-
27
.
33
-
35
-
47
-
32
-
32
.
79(C)
-
41
-
27
53
Flotation unit effluent (9-10)
IR-011 w/s1Hca gel
01 spersed Soluble
"9/1 ng/1
3
-
1
-
19
-
24
-
1
.
0
-
7
-
14
-
0
-
0
-
0
-
0
-
0
.
8
-
3
-
IS
'
0
-
0
-
46(C)
-
14
-
0
24
27
-
29
-
31
-
29
-
33
-
34
-
35
-
33
-
32
-
31
-
30
-
31
-
27
.
25
-
32
-
32
-
32
-
32
-
33(C)
-
27
-
25
35
Filtered
brine
lR-011
mg/1
73
.
68
.
63
-
66
.
64
.
70
.
71
.
74
.
69
-
60
.
63
.
65
.
64
.
66
-
62
.
64
..
61
.
64
.
68{C)

63
-
60
74
Surface
tension
Flow rate
Out SMwalngs
dynes/w n*/d «3/d
67
.
_
.
63
.
.
.
64
.
.
.
65
_
.
.
69
.
.
.
67
_
_
_
69
.
_
.
64

.
.
68
_
.
.
63(C)

.
-
63
69
4.6
3.8
7.7
4.9
12.3
12.3
13.5
12.9
11.6
8.8
16.3
19. 5
16.4
13.2
11.8
10.6
10.1
11.3
10.4
7.0
6.2
8.9
8.3
9.4
9.9
14.0
6.6
7.0
1.1
6.0
4.7
4.6
6.4
5.9
7.1
5.7
7.2
11.9
11.9
7.7







































1.1
19.5
               Not included in statistical analysis.  Salt crystals were observed after freon was evaporated for the test.
               Not included In statistical analysis.  Survey tea* inadvertently cut off flotation chemical feed to the system.
-------
ro
en
                                                 TABLE 146.  SS198G WELL TEST DATA
Well formation
TVD
7T
Gas
Oil
Epd
Water
~bpT
Lift gas
Hcfd
Pressure, pslg
SI BMP
FTP
Choke size
1/64 in.
API gravity
flowing to High Pressure Separator
G4
G40
G6D
G13D
Total (Average)
Flowing to Low Pressure
9.668
9,602
9.768
9.785
-
Separator
5.400
5.700
1.720
1.100
13.920

0
8
0
0
8

0
0
0
0
0

0
0
0
0
0

2.834
2.447
2.854
2.818
-

1.900
1.450
1.900
1,700
-

21
25
13
10
-

52.0
52.0
55.0
54.0
(53.2)

                 Combined Total
  400



14.320
585



593
                                                               195



                                                               195
600
          21
34.0
-------
             TABLE 147.  SS198G PRESSURE DROPS THROUGH SYSTEM



Location
Flowing Tubing
Pressure


Low Pressure
Separator

Oil Treater


CPI
Flotation Units
Pressure,
kPag
(psig)
4,140
(600)


640-650
(93-94)

430-450
(62-65)

0
0

Pressure drop
Pressure drop,
kPag
point or description (psig)

choke,
valves,
pipes

control valve
pipes

control valve
pipes



3,490-3,500
(506-507)


200-210
(29-31)

430-450
(62-65)




TABLE 148. SS198G
FLOTATION CHEMICAL
ADDITION

Addition rate
Day
01
02
03
04
05
06
07
08
09
10
Mean












dm3/d p
2.6
0
0
1.1
1.9
1.9
4.6
3.0
0
3.1
1.8
pmv^
500
0
0
90
200
230
490
720
0
320
255

(1)   Based on  average water  flow  through  the  flotation  unit  for  each  day.
     The usage of the other chemicals  is  shown  in  Table  149.



                                      262
-------
                      TABLE 149.   SS198G CHEMICAL ADDITION
                             Addition                  Addition rate
Chemical                       point                   dm3/dppmv


Tretolite RP2327             Well manifold             13.2
(Demulsifier)                ahead of 5A2

Tretolite SP246              Well manifold              1.7
(Scale inhibitor)            ahead of 5A2


(1)  Based on average fluid flow through the oil treater.


Observations and Operator Reports

     An effort was made to record any event that could affect effluent oil
content.  The operators were requested to provide information on upsets and
intermittent operational or maintenance procedures and the survey team made
their own observations.

     The Monosep was put into operation on Day 2, just prior to the 1300
sample period.  The unit experienced problems maintaining the proper level
and was out of service for two hours on Day 3.  This prevented the survey
team from obtaining a 1300 sample at 9-20 on Day 3.

     The Monosep skimmed a very minimal amount of froth until the afternoon of
Day 3.  The skimming rate then increased substantially, and overloaded the
piping.  The skimmings pumps could not overcome the increased line pressure.
The skimmings and the other miscellaneous flows were switched to the oil
storage tank the evening of Day 4.  The Monosep skimmings rate then dropped
until  the skimmings were switched back to the oil treater on Day 10 after the
0800 sample period.  The skimmings were switched to the oil storage tank after
the 1300 sample period on Day 10.

     Shut ins with durations of a few minutes each occurred on Days 7 and 10.
Well G5 shut in three times during the morning of Day 7.   The platform shut
in during the 0800 sample period on Day 10.

     Rain, deck washings, and vessel  flushing result in flow to the skim pile.
Significant flow to the skim pile causes the skim pile to pump oil  into the
skimmings recycle line.

     Rains occurred on Days 1 and 10.  The rain on Day 1  occurred before the
1500 sample period but no oil was pumped from the skim pile until  after the
1500 sample.  The rain on Day 10 started during the 1000  sample period and
lasted until the 1300 sample period.   Oil  pumped from the skim pile during
these times would be pumped to the oil  treater.

     Deck washings occurred the morning and night of Day  8.  The soap was


                                     263
-------
DW-9 Rig Wash from M-Chem.  Oil pumped from the skim pile during these times
would have been pumped to the oil storage tank.

     The Monosep was flushed out on Day 1 after the 1500 sample period.  This
caused the skim pile to pump oil to the oil treater.

     Oil storage tank bottoms were drained to the skim sump on Days 9 and 10.
On Day 9 the bottoms were drained between the 0800 and 1000 sample period.
The draining was performed during the 0800 sample period on Day 10.  Oil from
the skim pile was pumped back to the oil storage tank during these drainings.

     Accumulated liquid in the high-pressure separator was drained to the low-
pressure separator on Day 2 during the 0800 sample period and on Day 8 before
the 0800 sample period.

     The instrument gas scrubber liquid was also drained on Day 2 and Day 8.

DATA PRESENTATION AND EVALUATION

     Comprehensive data tables, summary tables and graphs for SS198G are
interspersed in this subsection.  In this discussion, flotation unit effluent
is the effluent from the Tridair, sample point 9-10.

Effluent Oil Content

     Table 145 presents a listing of oil content test results for the major
sampling points.  Table 150 presents a listing of test results on the Monosep
effluent (9-20).  Figure 88 presents a plot of GR-Oil out of the Tridair
flotation unit versus time.  Figure 89 presents the same plot for IR-Oil
content in and out of the Tridair.  The time-indexed plots are based on two
test results per day, except for the Tridair effluent GR-Oil  which is based
on four tests per day.

     The tabulated data and time-indexed plot show that the Tridair influent
is relatively uniform with only two of the 20 IR-Oil contents over 200 mg/1.
The two influent values over 200 mg/1  occurred on Day 4 at the same time as
the two highest CPI influent values.  The high oil  carried through the
Tridair as higher than average values.  Day 4 was the last full day that
skimmings were pumped back to the oil  treater.  The Monosep skimmings rate
was also substantially higher than on previous days.  The high skimmings
recycle rate could have contributed to these high values.

     The Tridair effluent was above average on Day 2.  The flotation aid feed
rate was not enough to note a change in the chemical reservoir on Day 2 or 3.
The low or possibly no chemical feed on Day 2 could have contributed to the
high effluent values.

     The Tridair effluent was high at 0800 on Day 10 because the valve that
shut off the flotation aid was closed.

     The ranges of test results, not including Day 10 at 0800, are as
follows:

                                      264
-------
                     TABLE 150.  SS198G BRINE TESTS ON SECOND FLOTATION UNIT EFFLUENT (9-20)
IM
en
tn

Suspended Solids
Sample time
Day Hour
01 08
01 13
02 08
02 13
03 08
03 13
04 08
04 13
05 08
05 13
06 08
06 13
07 08
07 13
08 08
08 13
09 08
09 13
10 08
10 13
Minimum
Maximum
IR-Oil
mg/1

_
_
21
36
-
34
36
27
25
-
30
25
34
30
33
27
29
59
47
21
59
Temperature

-
_
-
31.0
-
33.0
_
25.5
_
29.5
..
32.0
_
34.0
-
29.5
_
31.0
-
25.5
34.0
Total
mg/1
_
-
-
-
40
-
14
_
19
_
52
_
23
_
24
-
18
_
52
-
14
52
Freon
soluble
mg/1
_
-
-
-
2
-
0
_
25
_
3
_
1
_
3
-
2
_
9
-
0
25
Freon
insoluble
mg/1
.
-
-
-
38
-
15
-
3
_
50
-
22
_
21
-
17
_
43
-
3
50
Acid
soluble
mg/1
.
-
-
_
36
-
0
_
3
_
50
_
22
_
21
_
17
_
43
-
0
50
Fixed
mg/1
_
-
-
-
2
-
15
-
0
_
0
_
0
_
0
-
0
_
0
-
0
15
-------
             zoo
      6R
      OIL    100
      mg/|
               0 -
-EFFLUENT
                              2        3        4        5        678

                                                          DAY

                          Figure  88.  SS198G flotation unit performance, GR-oil vs time.
                                            10
cn
       IR
      OIL
      mg/l
            aoo
            200
             100
              o  -
                                                                    _L
                                                       567

                                                          DAY
                                            10
                          Figure 89.  SS198G flotation unit  performance, IR-oil vs time.
-------
     Flotation Effluent (9-10) GR-Oil - 2 to 45 mg/1,
     Flotation Effluent (9-10) IR-Oil - 27 to 53 mg/1,
     Flotation Influent (9-li) IR-Oil - 89 to 253 mg/1.

     Flotation unit effluent (9-10) oil content histograms for the two test
methods are presented in Figure 90 and Figure 91.  Figure 92 is a regression
plot of effluent GR-Oil versus IR-Oil.  In comparing oil content test results
by the two methods, it should be remembered that the samples were taken about
one minute apart from a flowing stream.  Therefore, the comparisons include
time-dependent sample differences as well as normal sampling and testing
variations.  Table 151 presents a summary.

     The data presented in Table 151 and the histograms indicate that the
mean oil content is higher by the IR-Oil test method than by the GR-Oil test
method.  The regression plot, Figure 92 and the correlation coefficient of
0.70 indicate only moderate correlation.

     All test results for dispersed oil and soluble oil as measured by the
IR-Oil w/Silica Gel test are listed in Table 145.  A summary of these test
results on the flotation unit effluent is presented in Table 152.

     An average of 83 percent of the oil in the effluent was soluble oil and
17 percent was dispersed oil.

     Linear regression plots of dispersed oil versus IR-Oil and GR-Oil are
presented in Figure 93.  Extrapolations of the linear regression lines to
zero dispersed oil indicate a residual IR-Oil of 31 mg/1 and a residual
GR-Oil of 14 mg/1 after all dispersed oil is removed.  The mean soluble oil
content of the flotation unit effluent was 30 mg/1.

     The mean soluble oil content of the gravity separator influent was 83
mg/1, significantly higher than the mean of 30 mg/1 of the flotation unit
effluent.

Surface Tension

     All surface tension test results are listed in Table 145.  The mean
surface tension of the gravity separator influent is 33 dynes/cm and of the
flotation effluent (9-10) is 66 dynes/cm.  The range for flotation effluent
test results was from 63 to 69 dynes/cm.  The linear regression equation for
effluent IR-Oil and surface tension is:

               IR-Oil = 333-4.5 (Surface Tension)
                    r = -0.68

     Although not included in the other statistical analyses, the test result
on Day 10 at 0800 when the system was upset was included in calculating the
regression equation.  A decrease in IR-Oil content of 4.5 mg/1 is indicated
for each one dyne/cm increase in surface tension.
                                     267
-------
             60



             50



             40

FREQUENCY

   %        30



             20



             10
n= 38
I = i a
s= 9.2
                        10
                                         so
                            20       30        40
                              GR-OIL,mq/|

Figure 90.   SS198G flotation  unit effluent,  GR-oil histogram.
FREQUENCY
             60
             50
             4O
             30
             20
             10
                                  1
 n s !9
 x » 36
 s * 7.8
                         10
                                          50
                            20        30        40
                               IR-OIL.mg/l
Figure 91.  SS198G flotation unit effluent,  IR-oil  histogram,
                                   268
-------
INJ
cn
                 50-
                 40-
       6R- OIL
                  20-
                  10 -
                  0
II  I  I  I  I  I  I   I  I  I   I  I  1  I  I   I  I  I  I  I  I   I  I  1  I  1  I   1  1  I  I  I  I -


     GR-OIL « - 13 + O. 85 (IR -OIL)
     r * 0.70
                       I  I
                                10
                I  I  I  I   I  I  I   I  I  I
                    20          30
 I  I  I  T  T I  I  I  I  I
SO          6O
                                               40

                                     IR/OIL.mg/l

Figure  92.  SS198G flotation unit effluent, infrared-gravimetric regression.
-------
              TABLE 151.  SS198G FLOTATION UNIT EFFLUENT (9-10)
                        GR-OIL AND IR-OIL COMPARISON
                                            Oil content
                                         GR-Oil
         IR-OIL
Number of tests, (n)
Mean, (x), mg/1
Minimum, mg/1
Maximum, mg/1
Standard Deviation.(s),mg/l
Number, (n)
Mean of Differences, (A), mg/1
Standard Deviation, (s.), mg/1
38
18
 2
45
 9.2
19
36
27
53
 7.8
 Paired tests

     18
     18
      6.7
                   TABLE 152.   SS198G SOLUBLE OIL  SUMMARY

Analysis or test
IR-011
Dispersed Oil
Soluble Oil
Flotation effluent
Range
mg/1
27-53
0-24
25-35
(9-10)
Mean
mg/1
36
6
30
Proportion
of total ,
percent
100
17
83

Suspended Solids

     The suspended solids tests were run on the gravity separator influent,
the Tridair influent and effluent, and the Monosep effluent.  The data are
recorded in Table 150 and Table 153 and a suspended solids summary for SS198G
is presented in Table 154.

     The data in Table 154 indicate that more than half of the solids were
Freon soluble.  There was no reduction in Freon insoluble suspended solids in
the flotation unit.

     Figure 94 presents time-indexed plots of Freon insoluble suspended solids
in the flotation unit influent and effluent, and of flotation effluent dis-
persed oil.  All samples were taken at the same time, 0800 each day.  The
plotted data do not demonstrate a distinct pattern that the dispersed oil con-
tent of the effluent is higher when suspended solids are higher in the flota-
tion unit influent or effluent.  As discussed in Section 18, the suspended
solids test method may not have sufficient precision to provide meaningful
                                     270
-------
         70 -
TOTAL
  OIL
 mg/l
         60 -
         30
          40
          20
          10
1  i   i  i   i  i   I  i   I  i  i   i  I   i  I   I  i   i  I   i  j   i  i  i   r

     • TOTAL IR-OIL vs DISPERSED  IR-OIL
       TOTAL IR-OIL ' 31 +0.93 (  DISPERSED  IR-OIL)
       r * 0.94

     • TOTAL GR-OIL VS   DISPERSED  IR-OIL
       TOTAL GR-OIL » 14  -1-0.31 (  DISPERSED IR-OIL)
       r * 0.68
                      TOTAL IR-OIL-DISPERSED  IR-OIL
                                      TOTAL GR-OIL - DISPERSED  IR-OIL
                       I   I  I   I
                       I   I  I   t  I  <   I  i   I  I   1  I   I  I   I
               0            3            10           IS
                            DISPERSED  IR-OIL, mg/l

              Figure 93.  SS198G  flotation unit effluent,
                total oil - dispersed  oil  regression.
                                    271
-------
                                    TABLE 153.  SS198G SUSPENDED  SOLIDS TESTS
ro
»-j
ro


Sample time
Day Hour
01 08
02 OB
03 08
04 08
05 08
06 08
07 08
08 08
09 08
10 08
Minimum
Maximum


Total
SgTT
34
27
32
35
34
31
39
17
35
59
17
59
Gravity
Freon'
soluble
35
30
34
31
29
27
40
16
28
34
16
40
separator, In (B--I)
Freon
Insoluble
•9/1
1
1
2
4
5
4
2
1
7
24
1
24
Acid
soluble
•9/1
1
1
2
4
5
4
2
1
7
20
1
20

Fixed
igTT
0
0
0
0
0
0
0
0
1
5
0
5

STT
25
33
33
41
35
36
15
17
48
34
15
48
Flotation unit, in (9-11)
Freon
soluble
mg/1
29
34
2
38
27
40
15
19
49
38
2
49
Freon
insoluble
»9/l
0
1
32
3
8
0
1
0
0
0
0
32
Acid
soluble
0
1
16
3
6
0
0
0
0
0
0
16

Fixed
SgTT
0
0
16
0
2
0
0
0
0
0
0
16

Total
SgTT
4
19
4
6
3
20
5
3
9
31
3
31
Flotation unit, out
Freon
soluble
6
20
5
8
0
4
3
7
1
28
0
28
Freon
insoluble
mg/1
1
2
4
4
3
16
3
1
B
2
1
16
(9-10)
Acid
soluble
mg/1
1
2
4
4
3
16
3
1
0
2
0
16


SH*
0
0
0
0
0
0
0
0
8
0
0
8
-------
                  TABLE 154.  SS198G SUSPENDED SOLIDS SUMMARY
                                         Average suspended solids, mg/1	
Suspended Solids                    8--i             9-li               9-10
Total
Freon Soluble
Freon Insoluble
Acid Soluble
Fixed
34
30
5
5
1
32
29
4
3
2
10
8
4
4
1

results at the solids concentration in the SS198G brine.

Filtered Brine

     The filtered brine IR-Oil content of SS198G effluent (9-10) was in the
range of 60 to 74 mg/1 with a mean of 66 mg/1.  The mean effluent IR-Oil con-
tent of unfiltered brine on SS198G was 36 mg/1.  The fact that the measured
oil content of filtered brine was consistently higher than that for unfiltered
brine indicates a bias to the high side for the filtered brine tests run on
SS198G effluent.

     The filtered brine mean IR-Oil content of the gravity separator influent
was 86 mg/1.

Flotation Unit (Tridair) Performance

     Figure 95 is a regression plot of IR-Oil in and out of the flotation
unit.  The slope of the linear regression line is only 0.075 indicating minor
effect of influent oil on effluent oil.

     The lack of the expected relationship between effluent oil and influent
oil may be because of the stable influent oil (89 to 253 mg/1) and the very
low hydraulic loading.  The hydraulic loading was in the range of 0.1 to 2.5
percent of the design capacity of the flotation unit.

Gravity Separator Performance

     The sample point for the gravity separator effluent is the same as for
the flotation unit influent (9-li).  The separator influent and effluent oil
content data are presented in Table 145.  The separator effluent mean IR-Oil
content was 130 mg/1.

     The results of the susceptibility to separation tests on the gravity
separator influent are presented in Table 155.  The mean IR-Oil content after
120 minutes of settling was 117 mg/1.  If the 117 mg/1 is compared to the
gravity separator effluent mean IR-Oil of 130 mg/1, the indication is that
the maximum potential for a gravity separator was being approached.
                                      273
-------
                          T	\	1	1	1	1	1	T
ro
               30
         z
         o
         Z
         UJ
         o
         z
         o
         o
                    EFFLUENT

                    DISPERSED

                       OIL
20
               10
                                                       EFFLUENT  DISPERSED  OIL
                                   I	I	I	I	I	I	I
                                                456

                                                            DAY
                                                                               9        10
                        Figure 94.   SS198G flotation unit Freon insoluble suspended  solids.
-------
                50-
                40-
                30-
ro
^
en
FLOTATION

   UNIT

EFFLUENT

  IR-OIL

  mg/l
                20-
                 10-
                      i—i—i—i—i—i—i—i—i—i—\—i—i—i—i—i—i—i—i—i—i—i—n—i—i—i—i   ri
                                      IR -OIL OUT  « 27+ 0.075 (IR-OIL IN)


                                      r - O. 38
                          Illllllllllllliri   I  I  1   I   I   I   1   I   I   I   T

                         20    40    60    80    100   120   140   160   ISO   200   220    240    260   280


                                                   FLOTATION UNIT INFLUENT IR-OIL, mg/l

                             Figure 95.   SS198G flotation  unit  in-out IR-oil regression.
-------
                TABLE  155.   SS198G  SUSCEPTIBILITY TO SEPARATION TESTS ON GRAVITY SEPARATOR  INFLUENT
                                          0
                                                            Settling times, minutes
                                                             15
                                    30
60
120
0
        Test Number 1
        Day 3, 1000
        IR-011, mg/1
        IR-011 W/S111ca Gel, mg/1
                                 258       228      237     194     173     144     101       245
                                 173                135                              25
ro
^i
en
        Test Number 2
        Day 5, 1000
IR-011, mg/1
IR-011  W/SllIca Gel, mg/1
220       194      220     173     131     165     118       245
139                139      -       -       -       46
        Test Number 3
        Day 7. 1630
        IR-011, mg/1
        IR-011 W/S1Hca Gel, mg/1
                                 199       194      169     182     186     148     131       186
                                 131        -        101      -       -       -       63
        Aye rage

        IR-011, mg/1
        IR-011 W/SllIca Gel, mg/1
                                 226       205      209     183     163     152     117       225
                                 148                125      -       -       -       45
-------
     The largest oil drop measured by the particle size test in the gravity
separator effluent had a diameter of um.

Monosep Performance

     Fifteen IR-Oil tests were performed on the Monosep effluent and are pre-
sented in Table 150.  The Monosep effluent IR-Oil content was in the range of
21 to 59 mg/1 with a mean of 33 mg/1.  The Monosep influent sample point is
the same as 9-10 and the data are presented in Table 145.  Monosep influent
dispersed oil peaks over 10 mg/1 occurred on Days 2, 4, 8, and 10.  The
Monosep removed the dispersed oil on Days 2, 4, and 8.

Miscellaneous Brine Tests

     All other brine test results for SS198G are listed in Tables 156, 157,
and 158.  The results for the following tests were generally in narrow ranges
for all samples:  temperature, pH, and specific gravity.  These parameters
were therefore not examined for correlation with sample-to-sample variation
in effluent oil content.  These parameters will be discussed in a later
section with respect to variations between platforms.

     Only one ionic analysis test and one sulfate reducing bacteria test per
sample point were run on SS198G.  These tests also are only significant with
respect to comparisons between platforms.
                 TABLE 156.  SS198G SUPPLEMENTARY BRINE TESTS

Sample time
Day Hour
01 08
02 08
03 08
04 08
05 08
06 08
07 08
08 08
09 08
10 08
Mean
Minimum
Maximum
Temperature,
8— i
39.5
30.5
37.5
• 37.0
33.5
37.0
37.0
39.0
36.5
37.0
36.5
30.5
39.5
9-11
37.0
28.0
34.0
35.5
29.5
33.5
35.0
36.0
32.5
33.0
33.4
28.0
37.0
°C
9-10
36.0
25.0
31.5
34.0
25.5
30.0
33.0
33.5
30.5
31.5
31.1
25.0
36.0
_£H_
9-10
7.1
7.1
7.1
7.0
7.5
7.0
7.0
6.8
6.9
7.0
7.1
6.8
7.5
Specif ic^1'
gravity
9-10
1.109
1.109
1.104
1.104
1.105
1.108
1.109
1.104
1.103
1.108
1.106
1.103
1.109

    Note?   Sample point  identification numbers (8—i, 9-li, 9-10) as
           shown on flow diagrams.
    (1)     Specific gravity is reported at temperature shown in table
           above.

                                     277
-------
                TABLE 157.   SS198G SULFATE REDUCING BACTERIA
     Sample point                         Bacteria per miTliliter

     Sump - Bottom (14--B)^                   1,000,000
     Oil  Treater - Bottom (6—B)                     0
     Gravity Separator (CPI)  - Bottom (8—B)         0
     Flotation Unit - Bottom  (9-IB)                  0
     Flotation Unit - Bottom  (9-2B)                  0

     Sample Day and Hour:  04  at  13


     (1)   Water stream off bottom of skim sump on production platform.


       TABLE 158.  SS198G IONIC ANALYSIS FLOTATION UNIT EFFLUENT (9-10)

     Constituent                                 Concentration,  mg/1
Sodium (Na)
Potassium (K)
Calcium (Ca)
Magnesium (Mg)
Barium (Ba)
Chloride (Cl)
Sulfate (SOd)
Alkalinity (as HCO,)
Iron (Total) *
Sulfide (as H2S)
41,000
390
2,730
600
244
71,200
12
366
6
0.15
     Total  Dissolved Solids
          Summation                                  116,000
          Gravimetric                                114,000
     Sample Day and Hour:  06 at 13
Crude Oil  Tests

     All  crude oil test results are listed in Tables  159 and 160.   The crude
oil temperature, specific gravity, and surface tension test results all  fell
in a narrow range with the exception of one temperature reading.

     The viscosity and boiling range distribution tests were limited in  number
to one and are of primary significance for comparisons between platforms.   Two
equilibration tests were run, each at a different oil/water ratio.

     The limited number of tests run on crude oil provide only a  limited
characterization of the crude oil.  Between-platform  comparisons  will  be
presented in Section 17.
                                     278
-------
          TABLE 159.  SS198G CRUDE OIL MISCELLANEOUS TESTS
                                                          (1)

Sample time
Day Hour
01 08
02 08
03 08
04 08
05 08
06 08
07 08
08 08
09 08
10 08
Mean
Minimum
Maximum
Temperature
31.5
25.0
31.0
32.0
22.0
32.5
32.0
35.5
28.5
31.5
30.2
22.0
35.5
Specific^
gravity
0.840
0.844
0.842
0.842
0.898
0.843
0.843
0.840
0.847
0.845
0.848
0.840
0.898
Surface tension'3'
dynes /cm
28
27
27
28
27
27
27
27
28
28
27
27
28
Sample time
Day    Hour
06
13
                          Viscosity at 37.77QC
 Kinematic
centistokes

   6.14
 Absolute
centipoise

   5.24
                          Equilibration at 82°C
                       Brine TDS = 116,000 mg/T
Oil /Water Ratio
IR-011, mg/1
IR-Oil W/Silica
IR-011 Filtered


Gel , mg/1
Brine, mg/1
4/1
12
6
10
0.15/1
9
4
8

(1)  Samples taken from LACT unit.
(2)  Specific gravity reported for temperature in table.
(3)  Surface tension measured and reported at ambient temperatures
     from 18°C to 24°C.
                                  279
-------
           TABLE  160.   SS198G  CRUDE  OIL  BOILING  RANGE DISTRIBUTION
                                           Run
Initial Boiling Point, °C                  150
Final Boiling Point, °C                    500
Boiling range, °C                   Percent recovered

Below - 200                                48.4
  200 - 250                                27.2
  250 - 300                                17.5
  300 - 350                                 3.2
  350 - 400                                 1.6
  400 - 450                                 1.2
  450 - 500                                 0.6

Total                                      99.7
                                     280
-------
                                  SECTION 14

                                PLATFORM  EI18CF
GENERAL
     The ten-day testing survey was conducted on Platform EI18CF from April 1
through April 10, 1980.

     A description of the production facilities, the test program, and data
presentation and evaluation are presented in this section.

     Three survey team members arrived at the platform on March 31 and the
test equipment was set up the same day.  Oil company personnel  unloaded the
equipment and provided living quarters, work space, sample taps, and the
utilities needed to conduct the Program.

     The complete testing survey was carried out without interruption by
weather, operating problems, or for any other reason.

FACILITIES AND OPERATIONS

Production From Wells

     Twenty-five wells were in production during the entire test program, and
eleven other wells were in production for one or more days.  All wells flowed
or were gas lifted to either a high- or low-pressure separator.

     Seventeen wells were flowing and the other nineteen wells  were gas lifted.
The average daily production calculated from well test data was 295 m3/d
"1,856 bpd) of oil, 2,709 m3/d (17,037 bpd) of water, and 1,078,000 std m3/d
 38,089 Mcfd) of gas.  The calculated water cut was 90 percent.

     The measured oil production for the ten-day period averaged 297 m3/d
(1,869 bpd) or 0.7 percent more than the calculated production.  The measured
water production averaged 2,920 m3/d (18,366 bpd) or 7.8 percent more than
the calculated production.

     Forty-eight percent of the oil was gas lifted, and ninety  percent of the
water was gas lifted.

Production Process System

     The flow of oil and water through the system is shown in Figure 96.


                                     281
-------
CO
ro
                              L E B t H D


                C  )  UNIT OEMflNATIOM   (rt) FLOW ELEMENT


                 VS7  SAMPLE POINT   	INTERMITTENT  FLOW
                                                                                                                 	1
                                 Figure 96.   Flow diagram,  production  process system, EI18CF.
-------
Design and operating data on major vessels are presented in Table 161.
Eleven wells flowed to two high-pressure separators operating in parallel
with the liquids then flowing to the low-pressure three-phase separator.
Twenty-five wells flowed or were gas lifted directly to the low-pressure sep-
arator.

     The oil stream from the low-pressure separator passes through an oil
treater for additional brine separation.  The oil is then pumped to the oil
storage tank and is barged to shore about every three days.  The barges hold
1,030 m3 (6,500 bbl).  No oil treating or water treating chemicals are added
on EI18CF.

     Figure 97 is a flow schematic for the water treating system.  The pri-
mary flow is the produced water from the low-pressure separator to the skim
tank which averaged 2,568 m3/d.

     Miscellaneous open drains discharge to the sump tank and the liquid is
pumped with a blowcase to the skim tank.  Three other blowcases receive fluid
from the pressure drains, low-pressure flare scrubber and high-pressure flare
scrubber.  The low-pressure flare scrubber blowcase also receives fluid from
all the gas scrubbers.

     Water from the low-pressure separator, oil treater and blowcases flows
through the skim tank and is pumped to the flotation unit and is then dis-
charged.  The flotation unit feed pump operates at a constant rate of 5,450
m3/d (34,300 bpd).  A recycle to the skim tank inlet is regulated by a skim
tank level controller.

     The skimmings from the skim tank and the flotation unit flow to a common
sump tank and are pumped to the oil treater.  The oil  storage tank bottoms
are pumped into the same line.

     The flow to the flotation unit was monitored continuously as described
in the subsection on Flow Monitoring.  The flows in Figure 97 were develop-
ed using this flow meter and the estimating procedures also described in the
flow metering subsection.

     The gravity separator on EI18CF is a cylindrical  skim tank.  Figure 98
is a dimensional  sketch which also shows probable flow patterns.  The inlet
is on the tank wall 4.27 m (14 ft) above the tank bottom.  The inlet distri-
butor is a 3.05 m (10 ft) long section of 25.4 cm (10-inch) diameter pipe
with slots in the bottom.  The distributor is in a horizontal  position
parallel to the tank wall.   The outlet is on the tank  wall  opposite the inlet
and near the tank bottom.  According to the drawings,  the tank has an internal
oil sump with the skimming weir 5.83 m (19.1 ft) above the bottom of the tank.
During normal operation the liquid level in the tank was 5.33 m (17.5 ft).

     The volume below the inlet distributor is 275 m3  (1,730 bbl).  At 5,450
m3/d (34,300 bpd) the calculated retention time is 73  minutes.

     The skim tank has 21 pans for collecting and disposing of solids.  The
tank was equipped with an automatic pan-draining controller that was operated

                                     283
-------
                                                 TABLE 161.   EI18CF VESSEL DATA  SHEET
ro
CO

5A1 I SBl
High pressure
gas/liquid
Vessel description separator
Trade Name or Vessel Type Vertical
Cylinder
Design Parameters
Dimensions, u, (ft)
Diameter. 0.0. 1.22(4)
Length. S.S. 4.57(15)
Length
Width
Height
2 2
Separation Surface Area, m , (ft )
Total
Per Cell
Separation Volume, m3, (bbl)
Total
Oil Phase
Water Phase
Number of Cells
Flow Rate. »3/day. (bpd)
Overflow Rate Per Cell. (w3/d)/w2.(bpd/ft2)(3)
Recycle Rate. Percent of Flow
Retention Time, min.
Average Operating Parameters
Temperature. °C(°F)
Pressure. kPag (psig) 7.310(1,060)
Flow Rate. »3/d (bpd)'2*
Flow Rate. Percent of Design
Overflow Rate Per Cell, (»3/d)/m2,(bpd/ft2)
Recycle Rate. Percent of Flow
Froth Flow, Percent of Flow
VESSEL DESIGNATION ON FLOW DIAGRAM -
5A2 6
Low pressure 01 1 treater
3-phase
separator
Vertical Cylinder Vertical Cylinder
Cone-Bottom Cone-Bottom


4.88(16) 3.05(10)
4.27(14) 9.14(30)
-
_
-

-
-

.
-
-
.
.
-
-
-
»
40(104) 55(131)
520(75) 310(45)
2.568(16.152) 354(2.226)
-
-
-
-
FIGURE 14-1
a
Gravity
separator,
skin tank
Vertical
Cylinder


9.06(29.7)
-
_
7.35(24.1)

64.5(694)
-

343(2.160)
-
-
_
„
-
-
-

39.1(102)
0(0)
5.450(34.300)
-
84(49)
-
-

9
Flotation unit.
dissolved gas
PCE


/ 1 1
7.92(26)(1)
-
— / 1 1
3. 53(11. 6)11'

49.3(531)
-

149(937)
.
-
_
10.900(68,570)
221(129)
-
20

38.2(101)
0(0)
2.920(18.366)
27
59(35)
-
0.5
            !1)  Separation area.
            2)  ----
    Effluent  flow.
(3)  Overflow  rate is surface area divided by flow rate.
-------
             OIL TREATER
                   SKIM TANK
FLOTATION UNIT
      FROM LP  C  5A2°

      SEPARATOR
        FROM
      BLOWCA8ES
                             (8—1  )
ro
oo
en
                                                                Ci-LJ
                                                         t
                                                                           C
                                              SKIMMED
                                              OIL TANK
WATER
 FLOW    3
       m /d
                                       14 __ 0   6__O   5A2O  BF   8__l  9F   9 __ t   9 __ 0


                                         13    354   2568   0   7949  IS    2935   2920


                                         82    2226   16152   0  50000  94    18460   18366
                                                                                                     TO

                                                                                                     SEA
                           Figure  97.  EI18CF water handling system flow schematic.
-------
  INLET I
            3.05m US.
            DISPERSER
               OIL
               SUMP

              [Li
                          7.35m
                                           5.83m
                                                        QjS3mJ
                                  9.06m Ola.
                                               OUTLET
                                               B-
about once per week.
the Gulf.
                         Figure 98.  EI18CF skim tank.
This dumped water and  any  settled solids directly to
     The flotation  unit on Platform EI18CF is a proprietary unit utilizing
pressurized full  flow  dissolved gas flotation.  Platform EI18CF is  the  only
platform in the survey with a dissolved gas flotation unit.  Figure 99  is a
dimensional sketch  of  the unit.  The gas is injected into the flotation unit
feed pump suction at an average of 260 std m3/d (9.2 Mcfd).  The flow then
spilts into two streams.  One stream flows back to the skim tank inlet  to
maintain the liquid level.  The other stream bypassed the retention tank which
was out of service  and flowed through a back-pressure valve and into the
center feed well  of the flotation tank.  Removal of float is accomplished by
a top rotating skimmer.  The shaft that turns the top skimmer is driven by
a bottom hydraulic  sweep.  The grit discharge flows to the Gulf 15  minutes out
of every 105 minutes.

     The design flow for this unit is 10,900 m3/d (68,570 bpd).  The average
operating flow based on effluent flow was 2,920 m3/d (18,366 bpd) or 27
                                    286
-------
                                     8.84m
Ml
i I
««^HMM«_«V«MWH«—nv y-'-' • —  i  — »••-'   —" JJ- T *
i I •!  i )}} I   FROTH     i i i
1 I! '  kx ^ ^\SUMP     '' i
                                                                   OUTLET
                                                                   i
                                                                   FROTH
                                                                 flOUTLET
    3.53m
                  Figure 99.  EI18CF flotation unit sketch.


percent of the design flow.  The average overflow rate was 59 (m3/d)m2 (35
bpd/ft2) with an average retention time of 73 minutes.  Overflow rates
frequently used in the design of dissolved gas flotation units range from 59
to 235 (m3/d)/m2 (i to 4 gpm/ft2).  The froth flow averaged 15 m3/d (94 bod)
or 0.5 percent of the effluent flow.

SITE SPECIFIC TEST PROGRAM
     The planned test program for brine samples is presented in Table 162.
The number of samples to be taken in ten days and the time the samples are to
be taken each day are listed.  The listed program was carried out with only
minor variations.  One variation was the addition of a sample point on the
flotation unit sludge drain.  The other was a change of the location of the
9—i sample point from upstream to downstream of the flotation unit feed pump.

     In addition to the brine tests, the following tests were run on crude oil
samples:  temperature, specific gravity, viscosity, boiling range distribution,
equilibration, and surface tension.

     Particle size distribution tests were run and are reported in Section 16.
                                     287
-------
                                          TABLE  162.    EI18CF  TEST SCHEDULE FOR THE MAJOR  BRINE  TESTS
ro
CO
00
field Tests
  Infrared Oil
  Temperature
  PH
  Water  Specific Gravity^
  Water  Surface Tension'  '
  IR-Oil U/Silica Gel
  IR-Oil Filtered Brine
  Susceptibility to Separation'
                                     (3)
         laboratory Tests
           Gravimetric 6Tl
           Suspended Solids
           Ionic Analysis
           Bacterial Culture        ,.,
           Particle Size Distribution14'
                                                                                              SAMPLE POINTS
                                                           V
                                                            9--0
                                                                                 9--1
                                                      No. of
                                                       tests
                                                      Time of
                                                       tests
            No. of
             tests
       Time of
        tests
                                                        20
                                                        10
                                                        10
                                                        10
                                                        10
                                                        20
                                                        20
8.13
  8
  a
  8
  8
8.13
8.13
20
10
8.13
  8
            No. of
             tests
    8--J	
       Time of
        tests
                                                                                                                             6--0
                                                                                                                                                   5A20
            No. of
             tests
Time of
 tests
No.  of
 tests
Tine of
 tests
20
10
                      10
                      10
                      10
                       3
8.13
  8
                        8
                        6
                        8
                       13
                                               40   8.10.13.15        10        8            -
                                               10       8            10        8           10        8
                                                1      (1)            -        -            -
                                               A maximum of five tests at sample points  selected In the field.
                                                3      13             3       13            3       13
          1)   Sampling times not  shown will be field scheduled.
          2)   Extra samples when  IR-Oil is high.
              IR-Oil w/Silica Sel at 0. 5, and 120 minutes.
              IR-Oil. IR-Oil w/Silica Gel. and filtered brine tests at same time.
 ••/

 Jl
                                                                                           NOTE:  Time of  tests listed Is by military hour.
-------
OPERATIONAL DATA AND OBSERVATIONS

     Measurements, observations, and records of operations are reported in
this subsection.

Flow Monitoring

     The water flow patterns are shown in Figure 96 and Figure 97.  The pri-
mary flow is the produced water from the wells.

     The influent to the flotation unit was monitored continuously with an
orifice-plate type flow meter.  The flotation unit froth flow rate was calcu-
lated four times daily.  The estimate was based on the rate of rise in the
skimmings pump sump tank.  Using this information, a flotation unit effluent
and froth flow rate were calculated for each sample period.  These flows are
recorded in Table 163.

     The skim tank skimming rate is reported as 0 in Figure 97.  This is
based on the fact that the oil skimming weir was 0.5 m (1.6 ft) above the oil
surface during all sample periods.  The skim tank liquid level was raised for
five hours on Day 6 after the 1500 sample period.  During that time, an
estimated 60 m3 (375 bbl) of oil was skimmed.

     The average flow from the blowcases was 13 m3/d (82 bpd).  The blowcases
gas was supplied by the fuel gas system.  Every time a blowcase operated it
was indicated on the fuel gas usage chart.  Based on this information a flow
rate was estimated for each sample period.  The blowcase flow ranged from 0
to 80 m3/d (504 bpd).

     The distribution of water from the low-pressure separator and the oil
treater is based on oil and temperature measurements at 5A20, 6—0, and 8—i
on Day 6 at 0800.  A balance based on this information indicated that 86 to
90 percent of the water was from the low-pressure separator.

Well Test Data

     The well test data provided by the operator are listed in Table 164.
The data are grouped according to whether the flow was to the high-pressure
or low-pressure separator.  The data for wells producing to the low-pressure
separator are further subdivided according to whether the well was flowing
or gas lifted.  The table also shows whether a well  produced all  the time  or
for only part of the survey period.

Pressure Drops Through System

     The formation pressures and the flowing tubing pressures for each well
were obtained from well test data.  Table 165 presents the ranges and traces
the pressure drops from the producing formation through the system.  The
table includes only the wells producing water.

     Table 165 shows that the greatest pressure drops occur from the formation
to the chokes, substantial drops occur at the chokes and the high-pressure

                                      289
-------
                                       TABLE 163.  EI18CF MAJOR BRINE TESTS
ro
10
O
Gravity separator influent (8--1)
IR-Oil w/sllica gel
Sample time
Day Hour
01 08
01 10
01 13
01 15
02 08
02 10
02 13
02 15
03 08
03 10
03 13
03 15
04 08
04 10
04 13
04 15
05 08
05 10
05 13
05 15
06 08
06 10
06 13
06 15
07 08
07 10
07 13
07 15
08 08
08 10
OS 13
08 15
09 08
09 10
09 13
09 15
10 08
10 10
10 13
10 15
Minimum
Maximum
IR-011
ng/1
245
.
298
.
339
.
441
-
323
.
253
.
268
_
222
.
229
.
262
.
245
-
270
-
208
-
266
-
2S7
-
813
-
221
-
294
.
241
-
188
-
188
813
Dispersed
•9/1
me
-
.
-
327
_
_
-
262
-
-
-
227
_
.
-
180
-
-
.
245
-
-
-
131
-
-
-
221
-
-
-
196
-
-
-
219
-
-
-
131
327
Soluble
•9/1
57
-
„
-
12
.
.
.
61
.
-
-
41
.
.
.
49
-
.
-•
0
-
-
-
77
-
-
-
36
-
-
-
25
-
-
-
22
-
«
-
0
77
Filtered
brine
IR-Oil
«9/l
8
.
.
-
8
.
-
-
a
-
-
'
204
.
.
-
10
-
-
-
7
-
-
-
7
-
-
-
9
-
-
-
12
-
-
.
8
-
-
-
7
204
Surface
tension
dynes/cm
72
-
.
-
72
-
-
-
72
.
-
-
69
.
-
-
70
.
-
-
72
-
-
-
73
-
-
-
72
-
-
-
70
-
-
-
72
-
-
-
69
73
Flotation unit
influent (9-1)
GR-011
mg/1
60
-
.
-
59
.
-
-
95
-
-
-
89
-
-
-
92
-
-
-
84
-
-
-
24
-
-
-
21
-
-
-
56
-
-
-
55
-
-
"
21
95
IR-Oil
•9/1
172
-
147
-
127
-
217
-
151
-
327
-
137
-
204
-
703
-
474
-
589
-
638
-
61
-
82
-
59
-
106
-
61
-
64
-
68
-
54
*
54
703
GR-011
•9/1
34
44
38
46
40
54
42
58
78
75
71
77
73
78
72
83
86
86
80
61
87
88
74
69
47
28
41
24
41
28
49
18
23
25
24
24
26
24
22
31
18
88
IR-011
•9/1
59
-
56
-
73
-
78
-
102
-
110
-
121
-
116
-
155
-
123
-
110
-
106
-
50
-
44
-
40
.
33
-
35
-
35
-
38
-
35
-
33
155
Flotation unit effluent (9-0)
IH-011 w/slllca oel
dispersed
•ig/1
51
-
54
-
69
-
75
-
74
-
78
.
90
.
82
.
131
-
82
.
94
-
106
-
42
-
36
-
39
-
26
-
29
-
29
.
35
.
32
-
26
131
Soluble
•9/1
8
-
2
-
4
.
3
-
28
-
32
-
31
.
34
-
24
.
41
-
16
.
0
-
8
-
a
-
i
.
7
-
6
-
6
.
3
-
3
-
0
41
Ff 1 tered
brine
IR-Oil
ng/1
10
-
10
-
7
.
7
-
8
.
7
.
11
-
11
-
13
.
9
.
8
-
90
.
7
.
9
-
9
-
7
.
11
-
10
-
a
.
10
-
7
90
Surface
tension
dynes/cm
50
-
-
-
56
.
.
.
44
.
-
.
43
.
.
.
45
-
-
.
55
.
.
.
69
.
.
.
67
.
.
.
67
-
_
.
69
.
.
-
43
69
Flow rate
Out Sk timings
i?/d
3.205
3.057
3,007
2.711
3.154
3.199
2,755
2,705
3,107
3,106
3,200
2.907
2.662
2.760
2.860
2.761
2,615
2,804
2.805
2,806
2,805
2,806
2,757
2.757
2.708
2.658
2.855
2,768
2.781
3.051
2.999
3,047
3.121
3.125
3.170
3,309
2,992
3.043
2,895
2.948
2.615
3.309
»3/d
5
5
5
5
6
11
11
11
4
5
9
7
4
6
5
4
2
11
9
9
10
8
8
8
a
a
10
46
34
60
13
14
39
36
39
49
20
19
19
15
2
60
-------
                                      TABLE 164.  EI18CF WELL TEST DATA
ro
Well
Formation
Flowing to High Pressure
36-22
36-30
36-31
65-11
65-12
65-15
65-19
65-26
65-29
67-43B
67-45
Total (Average]
Flowi ng to Low
65-5
65-7
65-260
65-27
67-23
67-500
Total (Average]
"S2" RA
"S2" RA
"K* RB
"F2" RA
"Fz" RA
"F2" RA
"A* RA
"Q" RA
"Q" RA
T RB
"Tt" RC

TVO
'ft
Separator
10.950
11.000
8.900
9.400
8.500
8.460
6.900
10.550
10.600
8.850
11.350
-
gas
icira

2.501
4.548
860
4.042
5,037
3.465
5.592
900
2.888
2.948
4.567
37.348
Oil
Bp3

26
56
1
37
48
29
77
19
28
34
51
406
Water

6
0
488
0
0
0
1
53
0
333
0
881
Lift gas
~ tefd '

0
0
0
0
0
0
0
0
0
0
0
-
Pressure, pslg
SlfiHP

4.776
4.750
-
4.060
3.940
3.755
3.070
-
4.670
4.200
4.411
-
FTP

2.750
.400
,200
.400
.550
,450
.700
.275
.400
2.500
2.500
-
Choke size
lM In.

12
25
24
23
24
15
25
15
19
18
17
-
Days of
API gravity production

48.3
45.2
46.3
47.8
51.9
51.0
52.8
42.9
50.0
51.0
46.0
(48.5)

All
All
All
All
All
All
All
All
All
7(PH).8.9.10
All

Pressure Separator
"P" RA
"M" RA
"K" RA
"P" RA
10.100
9.400
10.600
10.300
"0" RA SU 10.050
"N" RB

Gas Lift to Low Pressure
36-8
36-10
36-15
36-20
36-23
36-240
65-2
65-6
65-8
65-17
67-2
67-4
67-9
67-11
67-19
67-220
67-26
67-40
67-42
Total (Average)
Combined Total
"P" RB SU
"A" RB
"A" RB
"0" RB
"0" RB
"A" RB
"J" RA
"K" RA
"J2" RA
"M" RA
"N" RB
"N" RB
"0" RA SU
"0" RA SU
"K" RA
"N" RC
"0" RA SU
"Od" RA SU
"Pa RC

(Average)
9.300
-
Separator
10.000
6.900
6.900
9.600
10.050
-
8.800
9.200
8.900
9.400
9.400
9,300
10,050
10.050
9.100
9.700
10.050
10.050
9.400
-
-
785
53
190
1.665
1.059
114
3.866

9
127
40
33
51
31
49
35
78
53
157
56
72
62
138
13
58
33
155
1.250
42.464
2
40
224
1
227
109
603

13
108
34
17
17
26
14
19
47
50
139
22
106
54
26
29
61
50
110
942
1.951
60
210
240
0
122
409
1.041

0
297
223
1.195
1.554
1.291
232
1.233
779
1.051
1.104
950
912
1.170
1.363
1.188
770
503
1.830
17.645
19.567
0
0
0
0
0
0
-

170
380
350
474
445
380
340
260
340
307
320
350
78
200
280
470
55
320
312
5,831
5.831
«.
4.060
4.870
.
3.528
-
-

3.192
2.978
2.930
-
3.973
-
3.336
-
-
-
-
.309
.351
.367

.017
.348
3.862
4.380
-
-
750
575
725
1,050
2.100
500
-

90
100
90
150
200
150
200
220
290
400
250
90
210
180
400
170
110
150
195

-
14
12
15
11
13
19
-

open
open
open
open
open
open
32
open
open
32
40
open
open
open
open
open
open
open
open
-
-
53.6
47.0
37.0
41.3
39.4
37.7
(42.7)

39.1
39.6
39.0
38.5
37.0
37.0
37.3
37.8
38.0
38.0
38.4
37.6
38.7
38.3
36.7
30.9
38.4
38.0
39.2
(37.8)
(41.9)
10
All
All
10
All
All


All
All
1.2(AM).3-10
9.10
1.3-10
1,2(AM).3.4(PH).5-10
l-3.9(PM).10
1-3.8(PM),9(PM).10
AH
All
All
1-3
All
All
All
All
1(0800 & 1500). 2-10
All
All


-------
               TABLE 165.  EI18CF PRESSURE DROPS THROUGH SYSTEM
Location
  Pressure,
    kPag
   (psig)
    Pressure drop,
point or description
Pressure drop,
    kPag
   (psig)
Formation
(SIBHP)
Flowing Tubing
Pressure
High Pressure
Separator
Low Pressure
Separator


Oil Treater
Skim Tank
20,200-33,580
(2,930-4,870)
   620-18,960
   (90-2,750)
 7,205-7,480
 1,045-1,085)
   470-565
   (68-82)
   275-320
   (40-46)
    perforations,
    static head,
    pipes
    chokes,
    valves,
    pipes


    control valve,
    pipes


    control valve,
    pipes
                                        control valve,
                                        pipes
 9,450-29,220
(1,370-4,240)
   103-13,960
   (15-2,025)
 6,685-6,960
  (970-1,010)
                                        (1)
   210-565
   (30-82)
          (2)
                              275-320
                              (40-46)
(1)  Minimum and maximum pressure drops are to the low-pressure separator.
(2)  The minimum pressure drop is to the oil treater and the maximum is to
     the skim tank.
separator control  valve, and more minor drops from the low-pressure separator
on.

Chemical  Addition

     No oil  treating or water treating chemicals were added on EI18CF.
Methanol  is  added  at the high-pressure well  heads to prevent hydrate forma-
tion.  Methanol  was injected at a rate of 115 dm3/d (30 gpd).   The methanol
flows with the gas and fluid to EI18CF for processing.

     Bench scale studies were conducted by the operator to determine if
chemical  addition  would improve oil  separation in the flotation unit.   Chem-
icals from six companies were evaluated over a two-year period.  Significant
improvement  in oil separation was not obtained.
                                      292
-------
Observations and Operator Reports

     An effort was made to record any event that could affect effluent oil
content.  The operators were requested to provide information on upsets and
intermittent operational or maintenance procedures and the survey team made
their own observations.

     An Eposand treatment to consolidate sand was performed on Well 65-18
just prior to the  start of the  survey.  The well was opened up on Day 1 after
the 1000 sample period.  A total of 3.7 m3 (23 bbl) of treatment fluid flowed
from the well before  it was shut in after the 1500 sample period.

     The skim tank solids-collecting pans were drained from Day 4 after the
1500 sample period to Day 5 just before the 0800 sample period.

     The skim tank effluent IR-Oil was higher than the influent on Days 5 and
6.  The tank was operated with  a liquid level of 5.33 m (17.5 ft).  The tank
drawings show the oil skimming  weir 0.5 m (1.6 ft) higher at 5.83 m (19.1 ft).

     On Day 6 after the 1500 sample period, the flow from the skim tank to the
flotation unit was stopped.  This forced the skim tank to discharge through a
water leg to the Gulf and raised the skim tank liquid level high enough to
skim oil.  As the  liquid level  rose in the tank, the oil-water interface
became visible in  the sight glass.  The oil thickness was estimated to be
0.9 m (3 ft).  With the normal  operating surface at 5.33 m, a 0.9 m thick oil
layer would bring  the oil-water interface down to 4.4 m.  This is close to
'the inlet level of 4.27 m.  This closeness of the oil level to the inlet may
have resulted in the  inlet flow sweeping oil that had been previously separated
out of the tank.  This may have caused the higher oil content tests on Day 5
and Day 6.  The flow was returned to the flotation unit at about 2000.

     After the first five days  of the survey, the 9--i sample point was moved
from upstream to downstream of  the flotation unit feed pump.  The upstream
sample was taken from a horizontal 2.5 cm (1-inch) diameter pipe placed in-
side a horizontal 45.7 cm (18-inch) diameter pipe.  The feed pump suction was
taken from the larger pipe.  The open end of the 2.5 cm pipe was upstream of
the pump suction.  The downstream sample was taken from the side of a vertical
10 cm  (4-inch) diameter pipe immediately downstream of the pump.  The change
was made to ensure that the turbulence was sufficient to provide a representa-
tive sample.

     The rate of gas injected into the feed pump suction was increased on
Day 8 after the 0800 sample period.  The rate was increased from 250 to 280
std m3/d (9 to 10 Mcfd).

     The peak blowcase flow occurred on the afternoon of Day 2 and the first
three sample periods of Day 3.  The flow was water that had been produced for
injection and had carried over  with the lift gas to the compressor suction
scrubber.  The carryover was due to overloading the injection water separator.

     Rains and deck washings result in flow to the sump tank and the fluid
is pumped to the skim tank.  Rains occurred the night before Day 2, the

                                     293
-------
morning of Day 2, and the morning of Day 8.  Deck washings occurred on Day  9
after the 1500 sample period, using 50 to 75 dm3 of Shell degreaser, thereby
affecting the contents of the sump.

DATA PRESENTATION AND EVALUATION

     Comprehensive data tables, summary tables and graphs for EI18CF are
interspersed in the text of this subsection.

     Table 163 presents a listing of oil  content test results for the major
sampling points.  Figure 100 presents a plot of GR-Oil in and out of the
flotation unit versus time.  Figure 101 presents the same plot for IR-Oil
content.  The IR-Oil time-indexed plot is based on two test results per day.
The GR-Oil time-indexed plot is based on one influent and four effluent test
results per day.

     The tabulated data and time-indexed plot show that the flotation unit
influent IR-Oil is highly variable.  The influent IR-Oil has an upward trend
the first six days with all values over 125 mg/1 and a maximum of 703 mg/1.
The last four days the influent IR-Oil is relatively uniform ranging from 54
to 106 mg/1.  The skim tank oil was skimmed the evening of Day 6.  The skim-
ming stopped the increase in oil content through the skim tank and lowered
the oil concentrations in the flotation unit influent.  The flotation unit
influent GR-Oil is relatively uniform for the entire test period, ranging
from 21 to 95 mg/1.

     The ranges of test results are as follows:

     Flotation Effluent GR-Oil - 18 to 88 mg/1,
     Flotation Effluent IR-Oil - 33 to 155 mg/1,
     Flotation Influent GR-Oil - 21 to 95 mg/1,
     Flotation Influent IR-Oil - 54 to 703 mg/1.

     Flotation unit effluent oil content histograms for the two test methods
are presented in Figure 102 and Figure 103.  Figure 104 is a regression
plot of effluent GR-Oil versus IR-Oil.  In comparing oil content test results
by the two methods, it should be remembered that the samples were taken about
one minute apart from a flowing stream.  Therefore, the comparisons include
time-dependent sample differences as well as normal sampling and testing
variations.

     Table 166 presents a summary comparison of test results by the two
methods.

     The data presented in Table 166 and the histograms indicate that the
mean oil content is higher by the IR-Oil  test method than by the GR-Oil test
method.  The regression plot and the correlation coefficient of 0.91 shown in
Figure 104 indicate a significant relationship between results by the two
test methods.  The standard deviation of 20 mg/1 for differences in paired
tests indicates that there is not a uniform difference.
                                     294
-------
I\J
to
en
       6R
       OIL
             eoo
             700
             600
             soo
             40O
             300
             200
             IOO
                                                    INFLUENT
                                                        5        6
                                                          DAY
10
                           Figure  100.  EI18CF flotation unit performance, GR-oll vs time.
-------
ro
uo
en
              800
              700
              600
              500
       IR-OIL  400
       mg/l
              300
              200
               too
                                                         5        6

                                                            DAY
10
                        Figure 101.  EI18CF flotation unit performance,  IR-oil  vs  time.
-------
30-
—
20-
FREQUENCY -
10-
(
1 I 1



r
mmmm


mmm
Mmmm
20
J



mm
4
mmm
mmmm
o







III I 1 1 ' i 1 1 _
1*52
»s24 _
-
—

_|_L
mmm
mmmm
mmm
mmmm
\
60 ' 80 ' 100 ' 120 ' 140 ' 160
                                    GR-OIL, mq/l
       Figure  102.   EI18CF flotation unit effluent,  GR-oil  histogram.
FREQUENCY   _
    *
30-
-
-
20-
10-

l
r 1
I
« I
1
1 1 ' 1 1 1 _
T»76
«« 38


1 1

mm
mm







MM
•M




mmi


MM



1

mmm

•
•••

mmmm
mmm

n -
i i i
                                                 100     120    140     ISO
                                     IR-OIL, mfl/1
       Figure 103.  EI18CF flotation unit effluent,  IR-oil histogram.
                                  297
-------
       ISO
       140
       130
       120
        110
       100
        90
TOTAL
 OtL
mg/l
        70
        60
        4O
        30
        20
         10
r    i
t     i
                                       i     i
                                                               i     i
• TOTAL IR OIL VS  DISPERSED  IR OIL
 TOTAL IR OIL s-l.3+1.2  (  DISPERSED
           r 3 0.96
• TOTAL GR OIL VS  OISPERSEO  IR OIL
 TOTAL Gfl OIL * I2+O.S3( OISPERSEO
            r s 0.83
                                                 R OIL)
                                                  IR OIL)
                    TOTAL IR OIL -
                     DISPERSED  IR OtL
                                                      TOTAL GR  OIL -
                                                        DISPERSED  IR OIL
             I   I  1
              I  I   I
                                         i   I  1
                    20        4O        60        30        100
                                 DISPERSED   IR-OIL,  mg/l

                Figure 105.  EI18CF  flotation unit  effluent,
                    total  oil - dispersed oil regression.
                                                        120
                                       300
-------
     The mean soluble oil content of the skim tank influent was 38 mg/1,
significantly higher than the mean of 13 mg/1 of the flotation unit effluent.

Surface Tension

     All surface tension test results are listed in Table 163.  The mean
surface tension of the skim tank influent is 71 dynes/cm and of the flotation
effluent is 57 dynes/cm.  The range for flotation effluent test results was
from 43 to 69 dynes/cm.  The linear regression equation for effluent IR-Oil
and surface tension is:

                IR-Oil = 261-3.2 (Surface Tension)
                     r = -0.84

     A decrease in IR-Oil content of 3.2 mg/1 is indicated for each one dyne/
cm increase in surface tension.   The correlation between low surface tension
and high oil  content is significant.

Suspended Solids

     The suspended solids tests  were run on the skim tank influent, and the
flotation unit influent and effluent.  The data are recorded in Table 168 and
a suspended solids summary is presented in Table 169.

     The data in Table 169 indicate that all of the solids were Freon soluble.

     The suspended solids were consistent at all three sample points.  The
difference between maximum and minimum was 15 mg/1 at 8—i, 16 mg/1 at 9--i,
and 14 mg/1 at 9—0.

Filtered Brine

     The filtered brine IR-Oil content of the EI18CF effluent was  in the
range of 7 to 90 mg/1  with a mean of 13 mg/1.  Without the 90 mg/1  value,
the range is  7 to 13 mg/1 with a mean of 9 mg/1.

     The filtered brine IR-Oil of the skim tank influent was in the range of
7 to 204 mg/1, with a mean of 28 mg/1.  Without the 204 mg/1 value, the range
is 7 to 12 mg/1 with a mean of 9 mg/1.

Flotation Unit Performance

     Figure 106 is a regression  plot of IR-Oil  in and out of the flotation
unit.  The slope of the linear regression line is 0.14 and the correlation
coefficient is 0.79 indicating a significant effect of influent oil on eff-
luent oil.

     Figure 107 is a regression  plot of flotation unit effluent IR-Oil  con-
tent and percent hydraulic loading.  The slope of the linear regression line
is -9, indicating a negative relationship between hydraulic loading and
effluent oil.  The lack of the expected positive relationship between effluent
oil and hydraulic loading may be because of the moderately low and  uniform

                                     301
-------
                                   TABLE  168.   EI18CF SUSPENDED SOLIDS TESTS
CO
o
ro

Sample time
Day Hour
01 08
02 08
03 08
04 08
05 08
06 08
07 08
08 08
09 08
10 08
MtntMM
Max lam


Total
IgTT
23
16
23
26
30
31
19
26
26
26
16
31
Gravi ty
Freon
soluble
23
16
23
26
30
31
19
26
26
26
16
31
separator. In (8--i)
Freon
Insoluble
~»g7T
0
0
0
0
0
0
0
0
0
0
0
0
Acid
soluble
0
0
0
0
0
0
0
0
0
3
0
3

Fixed
igTT
0
0
0
0
0
0
0
0
0
0
0
0

Total
igTT
25
27
22
11
25
27
17
17
15
16
11
27
Flotation unit. In (9—1)
Freon
soluble
•g/1
25
27
22
11
25
27
17
17
15
16
11
27
Freon
Insoluble
0
0
0
0
0
0
0
0
0
0
0
0
Acid
soluble
•9/1
0
0
0
0
0
0
0
0
0
0
0
0

Fixed
igTT
0
0
0
0
0
0
0
0
0
0
0
0

Total
igTT
24
28
21
26
32
28
28
22
18
18
18
32
Flotation unit, out
Freon
soluble
24
28
21
26
32
28
28
22
18
18
18
32
Freon
Insoluble
•g/1
0
0
0
0
0
0
0
0
0
0
0
0
(9-0)
Acid
soluble
0
0
0
0
0
0
0
0
0
0
0
0


Fixed
igTT
0
0
0
0
0
0
0
0
0
0
0
0
-------
                 TABLE 169.  EI18CF SUSPENDED SOLIDS SUMMARY
                                       Average suspended solids, mg/1
Suspended  Solids                       8--i        9—i          9--0
Total
Freon Soluble
Freon Insoluble
Acid Soluble
Fixed
25
25
0
0
0
20
20
0
0
0
25
25
0
0
0

hydraulic loading.  The hydraulic loading was in the range of 24 to 30 percent
of the design capacity of the flotation unit.

     The flotation unit sludge drain bypasses the final effluent sample point
and flows to the Gulf.  Five IR-Oil tests were performed on the sludge drain
stream to compare the oil content of the sludge drain and the final effluent.
The comparison is presented in Table 170.  The means are essentially the same.

Gravity Separator Performance

     The sample point for the skim tank effluent is the same as for the flota-
tion unit influent (9—i).  The skim tank influent and effluent oil content
data are presented in Table 171 and Table 163.  The skim tank effluent mean
IR-Oil content was 222 mg/1.

     The results of the susceptibility to separation tests on the skim tank
influent are presented in Table 172.  The mean IR-Oil content after 30 minutes
of settling was 68 mg/1.  If the 68 mg/1 is compared to the skim tank effluent
mean IR-Oil of 222 mg/1, it indicates that additional oil could be removed by
static settling.

     The largest oil  drop detected by the particle size test in the skim tank
effluent had a diameter of 97 ym.

     The IR-Oil test results in and out of the skim tank and up and down-
stream of the pump are presented in Table 171.  As discussed in the Observa-
tions subsection, the oil content was higher out of than into the skim tank
on Day 3 at 1300 and Days 5 and 6.

Miscellaneous Brine Tests

     All other brine test results for EI18CF are listed in Tables 173, 174,
175 and 176.  The results for the following tests were generally in narrow
ranges for all samples:  temperature, pH, and specific gravity.  These param-
eters were therefore not examined for correlation with sample-to-sample
variation in effluent oil content.  These parameters will be discussed in a
later section with respect to variations between platforms.


                                      303
-------
   160
   140
O
 I
<£
— 100
H
UJ
UJ
fc
o
3
U.
   60
   eo
   20
         I  I  I  I
I  I  I  I   I  |  I  I  I  I  |
!  I  I  I    I   I  I   I    I  I  I  I
             IR -OIL oul<444-O.I4(IR-OILIn)
                     r«0.79
            •I   I  I  I  I  I   I  I  i  I  I  I  I  i
                                    1
                     J
                                                              |  1   I  I   I  |
I  III
                            I  I  I   I  I   I  I  I-  »  I  I  t  I  I  i  I  I  I  I   I  I   I  I
100        200        300         400         500         600
               FLOTATION UNIT INFLUENT   IR-OIL,   mfl/l
    Figure 106.  EI18CF flotation unit  in-out  IR-oil  regression.
                                                                                         700
-------
FLOTATION
   UNIT
EFFLUENT
  IR-OIL
  mg / I
   160
   140
   120
   100
   8O
   60
   40
   20
            T  i  j  i   i  i  i  |  i  i   i  i  j  i  i   i  i  |   i  r
                                                                       I  I   i  i  i
               IR-OIL » 317-9 (HYDRAULIC LOADING)

                   r » -0.41
            I  III  I   I  I  I  j	I  1  i  I   I  I  I   I	I  L	I  I  I  I  I  I  I  I   I  I  I   I  I
                            10           IS          20

                                HYDRAULIC LOADING ,  %
                                                                        25
30
Figure 107.   EI18CF flotation unit hydraulic loading - infrared oil regression.
-------
              TABLE  170.   EI18CF  FLOTATION  UNIT  SLUDGE  DRAIN
Sample time
Day Hour
01 1300
02 1300
04 1300
08 1300
09 1300
Mean
Minimum
Maximum
IR-011, mg/1
Final effluent
56
78
116
33
35
64
33
116

Sludge drain
60
88
114
29
36
65
29
114

             TABLE  171.   EI18CF  GRAVITY  SEPARATOR  OIL  CONTENT

Sample time
Day Hour
01 0800
01 1300
02 0800
02 1300
03 0800
03 1300
04 0800
04 1300
05 0800
05 1300
06 0800
06 1300
07 0800
07 1300
08 0800
08 1300
09 0800
09 1300
10 0800
10 1300
MeanU)
Minimum/, I
Maximunr '

Influent
8-i
245
298
339
441
323
253
268
222
229
262
245
270
208
286
257
813
221
294
241
188
334
208
813
IR-Oil , mq/1
Effluent
Upstream of pump
172
147
127
217
151
327
137
204
703
474
589
638
196
82
-
360
172
131
-
-
310
82
638

(9--i )
Downstream of pump
—
-
-
-
-
-
-
-
-
-
511
351
61
82
59
106
61
64
58
54
177
61
511

(1)   Includes only tests  when  an  IR-Oil  was  run  upstream and downstream
     of pump.

                                      306
-------
                             TABLE  172.  EI18CF SUSCEPTIBILITY TO SEPARATION TESTS

                                         ON GRAVITY SEPARATOR INFLUENT
co
o


Test Number 1
Day 3, 1000
IR-011, mg/1
IR-Oil W/Silica Gel, mg/1
Test Number 2
Day 5, 1000
IR-011, mg/1
IR-Oil W/Silica Gel, mg/1
Test Number 3
Day 7, 1000
IR-Oil, mg/1
IR-Oil W/Silica Gel, mg/1
Average
IR-Oil, mg/1
IR-Oil W/Silica Gel, mg/1

0
311
253
163
135
229
163

234
184
Settling times
2 5 15
196 163 102
114
155 143 98
98
168 147 98
110

173 151 99
107
, minutes
30 60 120
65 56 40
33
69 47 38
31
69 45 38
29
I
68 49 39
31

0
315
180
270

255
-------
                TABLE  173.  EI18CF SUPPLEMENTARY BRINE TESTS
Sample time
Day Hour
01 08
02 08
03 08
04 08
05 08
06 08
07 08
08 08
09 08
10 08
Mean
Minimum
Maximum
Temperature,
8— i
39.5
40.0
41.5
39.5
38.5
40.5
39.5
39.5
40.5
40.0
39.9
38.5
41.5
9— i
40.0
38.0
39.5
38.5
38.5
37.5
39.5
39.5
39.5
40.5
38.1
37.5
40.5
°C
9—0
40.0
38.0
38.5
38.5
37.5
37.5
37.5
38.0
38.0
38.0
38.2
37.5
40.0
9—0
6.5
6.2
6.3
6.3
6.1
6.2
6.2
6.1
6.4
6.3
6.3
6.1
6.5
Specific^)
gravity
9—0
1.137
1.137
1.135
1.145
1.140
1.144
1.137
1.145
1.136
1.145
1.140
1.135
1.145
Note:  Sample  point  identification numbers (8—i, 9—i,  9—0)  as  shown on
       flow diagrams.

(1)    Specific  gravity  is reported at temperature shown in  table above.
           TABLE 174.   EI18CF BRINE TESTS AT MINOR SAMPLING  POINTS

Sampje
Day
04
06
time
Hour
08
08
IR-011,
5A20
249
222
mg/1
6—0
192
392
Temperature,
5A20
40.5
39.0
°C
6—0
57.0
53.0
Note:  5A20 is  the  low  pressure separator effluent.
       6—0 is  the  oil  treater effluent.
                                    308
-------
             TABLE 175.  EI18CF SULFATE REDUCING BACTERIA
    Sample  point
Bacteria per milliliter
   Sump - Bottom (14—B)
   Low Pressure Separator - Out (5A20)
   Oil Treater - Bottom (6—B)
   Gravity Separator - Bottom (8--B)
   Flotation Unit - Bottom (9—B) (1)

   Sample Day and Hour:  04  at 16
     1,000,000
          0
          0
        10-100
          0
   (1)  Special Bottom Dump Line.
       TABLE 176.   EI18CF IONIC  ANALYSIS  FLOTATION UNIT  EFFLUENT
Constituent
    Concentration,  mg/1
Sodium (Na)
Potassium (K)
Calcium (Ca)
Magnesium (Mg)
Barium (Ba)
Chloride (Cl)
Sulfate (S04)
Alkalinity (as HC03)
Iron (Total)
Sulfide (as H2S)

Total Dissolved Solids
     Summation
     Gravimetric

Sample Day and Hour:   10 at 14
          56,625
             400
           4,030
             997
             323
         102,000
               5
             146
              18
               0.15
         164,000
         162,000
                                 309
-------
     Only one ionic analysis test and one sulfate reducing bacteria test per
sample point were run on EI18CF.  These tests also are only significant with
respect to comparisons between platforms.

Crude Oil Tests

     All crude oil test results are listed in Table 177 and Table 178.  The
crude oil specific gravity, and surface tension test results fell in narrow
ranges.

     The viscosity and boiling range distribution tests were limited in number
to one and are of primary significance for comparisons between platforms.  Two
equilibration tests were run, each at a different oil/water ratio.

     The limited number of tests run on crude oil provide only a limited
characterization of the crude oil.  Between-platform comparisons will be
presented in a later section.
                                      310
-------
           TABLE 177.  EI18CF CRUDE OIL MISCELLANEOUS TESTS
Sample  time
DayHour
                Temperature
             Specific
             gravity
                   ^    Surface tension^3)
                            dynes/cm
01
02
03
04
05
06
07
08
09
10
08
08
08
08
08
08
08
08
08
08
36.
33.
33.
33.
25,
27.0
42.0
37.
40,
.5
.5
.3
.5
.5
.5
.5
41.5
0.810
0.812
0.813
0.811
0.816
0.816
0.806
0.806
0.809
0.804
26
26
27
27
27
26
27
26
26
26
Mean
Minimum
Maximum
                   35.1
                   25.5
                   41.5
              0.810
              0.804
              0.816
                                26
                                26
                                27
Sample time
Day    Hour
10
14
                   Viscosity at 37.77°C
                 Kinematic       Absolute
                centistokes     centipoise
2.95
              2.44
                          Equilibration at 82°C
                       Brine TDS =  164,000 mg/1
Oil /Water Ratio
IR-Oil
IR-Oil
IR-Oil
, mg/1
W/Silica
Fil tered

Gel,
Brine

mg/1
, mg/1
4/1
10
10
16
O.ll/
9
7
12
1




(1)  Samples taken from oil treater.
(2)  Specific gravity reported for temperature  in table.
(3)  Surface tension measured and reported at ambient  temperatures
     from 20.5°C to 33.2°C.
                                   311
-------
                TABLE  178.   EI18CF CRUDE OIL BOILING  RANGE  DISTRIBUTION
                                           Run
Initial Boiling Point, °C                  150
Final Boiling Point, °C                    480
Boiling range, °C                   Percent recovered

Below - 200                                37.1
  20 - 250                                 23.4
  250 - 300                                27.3
  300 - 350                                 7.5
  350 - 400                                 2.1
  400 - 450                                 0.3
  450 - 500                                 0.0

Total                                      97.7
                                      312
-------
                                 SECTION 15

                               PLATFORM SM130B
GENERAL
     The ten-day testing survey was conducted on Platform SM130B from April 16
through April 25, 1980.

     A description of the production facilities, the test program, and data
presentation and evaluation are presented in this section.

     Three survey team members arrived at the platform on April 13.  The
equipment was not unloaded until the evening of April 15 because of undulating
seas.  The equipment was set up that evening and the testing began the next
morning.  Oil company personnel unloaded the equipment and provided living
quarters, work space, sample taps, and the utilities needed to conduct the
Program.

     A platform shut in on Day 6 caused the sampling schedule to be altered
on that day.  The sampling periods on Day 6 were 1600, 1800, 2000 and 2200.

FACILITIES AND OPERATIONS

Production From Wells

     Twenty-one wells were producing.  Five wells were shut in for a day or
less.  All wells flowed or were gas lifted to the low-pressure three-phase
separator.

     Eighteen wells were flowing and the other three wells were gas lifted.
The average daily production calculated from well test data was 2,730 m3/d
(17,170 bpd) of oil, 631 m3/d (3,966 bpd) of water, and 237,200 std m3/d
(8,377 Mcfd) of gas.  The calculated water cut was 19 percent.

     The measured oil production for the ten-day period averaged 2,554 m3/d
(16,067 bpd) or 6 percent less than the well test data.  The measured water
production averaged 690 m3/d (4,340 bpd) or 9 percent more than the well test
data.

     Four percent of the oil was gas lifted and fifty-nine percent of the
water was gas lifted.

Production Process System


                                     313
-------
     SM130B is the newest platform in the survey with initial processing
beginning in August, 1979.  The flow of oil and water through the system is
shown in Figure 108.  Design and operating data on major vessels are
presented in Table 179.  The oil/water/gas flow is from the wells to the
low-pressure gas-liquid separator.

     A foam inhibitor, Dow Corning 200, is added to the produced fluids at
the well manifold ahead of the low-pressure separator.  No other oil treating
or water treating chemicals are used on SM130B.

     The oil flows from the low-pressure separator to Platform A for further
treatment.  The water flows through the desander to the corrugated plate
interceptors (CPI).

     Figure 109 is a flow schematic for the water treating system.  The pri-
mary flow is the produced water from the low-pressure separator through the
desander to the CPIs.  This flow averaged 971 m3/d.  Water from the CPIs
flows through the flotation unit and is discharged.

     The skimmings from the CPIs and the flotation unit flow to the wet-oil
tank.  Miscellaneous drains discharge to the skim sump, and any oil recovered
is pumped to the wet-oil tank.  The water from the skim sump is discharged to
the skim pile.  Oil and water that accumulates in the wet-oil tank are pumped
to the low-pressure separator.  The wet-oil-tank pump substantially increased
the flow through the water treating system when operating.

     The test treater discharged into the water line from the low-pressure
separator to the desander.

     The final effluent flow was monitored continuously as described in the
subsection on Flow Monitoring.  The flows in Figure  109 were developed using
this flow meter and the estimating procedures also described in the flow
monitoring subsection.

     SM1308 is the only platform in the survey with a desander in operation.
The desander consists of twelve hydrocyclones, six of which were in service.
The hydrocyclones are used in parallel.  In a hydrocyclone, pressure energy is
converted into centrifugal force by tangentially feeding the produced water
into the conical vessels.  The centrifugal forces developed multiply the set-
tling velocity of the suspended solids, driving them outward toward the coni-
cal wall and downward into a centrifugally accelerating spiral along the wall
to the solids discharge point of the cone.  The solids are discarged to a
chamber beneath the cones.  The chamber is isolated from the cones and
flushed with utility water once every two hours.

     The liquid phase being lighter, moves inwardly, and upwardly as a spiral-
ing vortex to the liquid discharge.  The desander inlet pressure averaged 97
kPag with the wet-oil-tank pump on and 57 kPag with the pump off.

     The CPI units are gravity separators of proprietary design supplied by
Monarch Separators, Inc.  Oil separates as the water flows between parallel
plates spaced approximately 2 cm (0.75 in.) apart.  Figure 44 is an


                                     314
-------
CO
»-»
en
                                                                                            GD jr~
                                                                               T	=f]
                                                                               t      ,	v_
                                                                                |      IA.IMTU-
                                                                                !         0     &>-.
                                                                                         f  GD

	




OIL
UNH




1
	 1




*t
t






]





fftOTH









l^>



w ttr
o/«
CN






cn
ftOTATIOH
UNIT









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(i

I » i
« ur
ft/*
en
I






o y





















TO
9U

                         t t a e N o

                (  )UMIT OESI6NATIOH ^E^FLOW ELEMENT


                 \»/ SAMPLE POINT	INTEKUITTENT
                                Figure 108.   Flow diagram, production process system,  SM130B.
-------
                                        TABLE 179.   SM130B VESSEL DATA SHEET
u>
»-»
en




Vessel description
Trade Name or Vessel Type

tesign Parameters
Dimensions, m. (ft)
Diameter. O.D.
Length, S.S.
Length
Width
Separation Surface Area, m2, (ft )
Total
Per Cell
Separation Volume, m3, (bbl)
Total
Oil Phase
Water Phase
Number of Cells
Flow Rate, m3/day, (bpd)
Overflow Rate Per Cell. (m3/d)/»2.(bpd/ftZ/5)
Recycle Rate, Percent of Flow
Retention Time, win.
Average Operating Parameters
Temperature, °C(°F)
Pressure, kPag (psig)
Flow Rate, m3/d(bpd)'4)
Flow Rate. Percent of Design
Overflow Rate Per Cell. (m3/d)/m2.(bpd/ft2)
Recycle Rate, Percent of Flow
Froth Flow, Percent of Flow
[1) Proprietary unit with two plate packs.
[2) Based on removing 40 MM oil drops.
3) Separation area.
41 Effluent flow.
5) Overflow rate is surface area divided by flow rate.
VESSEL
5A2
Low pressure
3-phase
separator
Vertical Cylinder
Cone-Bottom


4.88(16)
3.66(12)

-
-

-
-
-
-
-
-
-
-

40.9(106)
630(91)
971(6,107)
-
-
-
-





DESIGNATION ON FLOW DIAGRAM -
8A & SB
Gravity
separator,
CP1
Monarch'1'



.
-

-
-

-
-
-
-
3, 820(24. 000) '2*
-
-
-

40.2(104)
0(0)
970(6.101)
25
-
-
-





FIGURE 15-1
9
Flotation unit.
mechanical ,
dispersed gas
Wemco
Model 84


_
6.91(22.7){2j
1.93(6.3) (!)

13.3(143)
3.33(35.8)

17(110)
-
-
4
6,135(38,585)
1,840(1.080)
-
4

40.1(104)
0(0)
690(4.340)
11
207(121)
-
41





-------
              LP SEPARATOR
 CPI GRAVITY

 SEPARATORS
(2 IN PARALLEL)
FLOTATION UNIT
         FROM TEST THEATER
CO
                                                                                             ( •--
                                                                                                        TO
                                                                                                       SEA
WATER
FLOW




m3/d
bpd
8F

1
6
8 	 1

971
6IO7
9F

280
1761
9 	 1

970
6101
9 	 0

690
4340
                           Figure 109.   SM130B water handling system flow  schematic.
-------
undimensioned representational sketch of a CPI unit.

     The CPI units on SM130B each have two packs.  There are three units but
only two units were in operation.  The approximate dimensions of each pack are
1 m high, 1 m wide, and 1.75 m long.  Based on the manufacturer's recommended
sizing procedure and the conditions prevailing on SM130B during the survey,
the two CPI units in operation should accomplish the separation of 40-micron
oil drops at flow rates up to 3,820 m3/d (24,000 bpd).  Average hydraulic
loading was estimated to be 970 m3/d (6,101 bpd), or 25 percent of design.

     The flotation unit (Wemco 1+1, Model 84) is a proprietary four-cell
unit with mechanical gas eduction.  This type of unit was described in Section
6 and is depicted in Figure 6.  The design flow for the unit is 6,135 m3/d
(38,585 bpd).  The average operating flow based on effluent flow was 690 m3/d
(4,340 bpd) or 11 percent of design flow.  The average froth flow was 280
m3/d or 41 percent of the forward flow.

SITE SPECIFIC TEST PROGRAM

     The planned test program for brine samples was accomplished as presented
in Table 180.  The number of samples to be taken in ten days and the time the
samples were to be taken each day are listed.

     In addition to the brine tests, the following tests were run on crude oil
samples:  temperature, specific gravity, viscosity, boiling range distribution,
equilibration, and surface tension.

     Particle size distribution tests were run and are reported in Section 16.

OPERATIONAL DATA AND OBSERVATIONS

     Measurements, observations, and records of operations are reported in
this subsection.

Flow Monitoring

     The water flow patterns are shown in Figure 108 and Figure 109.  The
flotation unit effluent was monitored continuously after Day 2 at 0800.   The
flow was monitored with a turbine type flow meter.  These flow rates are re-
ported in Table 181.  The flotation unit and CPI skimmings rates were calcu-
lated four times daily.  The estimates were based on the rate of rise in the
wet-oil tank.  The average flow rates are shown in Figure 109.

     Practically all the skimmings flow was from the flotation unit.  The
CPI skimmings were minimal.   The  CPI's  oil  skirnminq weirs were set high
enough to build up an oil layer and skim more oil than water.

     The wet-oil-tank pump is turned on and off automatically, controlled by
a level control.  The wet-oil tank is a large vessel and the on and off
periods of the pump can be quite long in duration.  The on periods averaged
5 hours with a maximum of 21 hours and the off periods averaged 6.5 hours
with a maximum of 41 hours.  The length of the on and off periods is

                                     318
-------
LP
SEPARATOR



DESANDER


GRAVITY
SEPARATORS
Y „

FLOTATION
UNIT


                                       TABLE  180.    SM130B  TEST  SCHEDULE  FOR  THE  MAJOR BRINE TESTS
co
     9—0
No.  of
 tests
ffiToT
 tests
                                                                                            SAMPLE POINTS
                                                                                    9--1
                                                                               No.  of
                                                                               tests
                                 Tine of
                                  tests
                                                                                               No. of
                                                                                               tests
                                                                                                              8K-1
                                                   Time of
                                                    tests
                                                                                                                                     V
                                        Ho. of
                                         tests
                     s-o
                       Time of
                        tests
Field Tests
  Infrared Oil
  Temperature
  pN
  Uater Specific Gravity-.
  Water Surface Tension1  '
  IR-Oil U/SUica Gel
  IR-Oil Filtered Brine       n.
  Susceptibility to Separation'  '

Laboratory Tests
  Gravimetric Oil
  Suspended Solids
  Ionic Analysis
  Bacterial Culture
  Particle Size Distribution (4)
                                                       20
                                                       10
                                                       10
                                                       10
                                                       13
                                                       20
                                                       20
 8.13
   8
   8
•   8
   3
 8.13
 8.13
                          20
                          10
8.13
  8
                                                     20
                                                     10
                                                   10
                                                   10
                                                   10
                                                    3
8,13
  8
                           3
                           Q
                           8
                          13
40   8,1C.13.15            10       8
10       8                10       8               10
 1       (1)                -       -
A maximum of five tests at sample points selected in  the field.
 3       13                 3       13                3
                                                                     10
                                                                     10
                                                                                                                                  10
                                                                                                                   13
          (1)  Sampling times not shown will  be field scheduled.
          (2)  Extra  samples when IR-Oil is high.
          (3)  IR-Oil H/Silica Gel  at 0. 5. and 120 minutes.
          (4)  IR-Oil, IR-Oil w/Silica Gel. and filtered brine tests at same time.
                                              NOTE:  Time of tests listed Is by military hour.
-------
                                     TABLE 181.   SM130B MAJOR BRINE TESTS
co
ro
o
Gravity separator Influent (8K-i)
Sample tine
Day Hour
01 08
01 10
01 13
01 IS
02 08
02 10
02 13
02 IS
03 08
03 10
03 13
03 15
04 08
04 10
04 13
04 IS
OS 08
05 10
OS 13
OS IS
06 16
06 18
06 20
06 22
07 08
07 10
07 13
07 IS
08 08
08 10
08 13
08 IS
09 08
09 10
09 13
09 IS
10 08
10 10
10 13
10 IS
Minimum
Maximum
IR-Oil
mg/1
261
.
436
_
322
_
261
.
266
_
261
-
619
-
379
.
314
.
11.549
-
218
-
610
-
501
.
401
-
349
-
322
-
418
-
445
-
1.351
-
1,678
-
218
11.549
IR-Oil w/silica gel
Dispersed
209
-
-
.
248
-
-
-•
209
.
.
-
540
-
-
-
266
-
-
-
105
-
-
-
436
-
-
-
292
-
-
-
336
-
-
-
1.090
-
-
-
105
1.090
Soluble
mg/1
52
-
-
.
74
-
-
.
57
.
.
-
79
.
-
.
48
-
-
-
113
.
-
-
65
.
-
-
57
-
.
-
82
-
-
-
261
-
-
-
52
261
Filtered
brine
IR-Oil
mg/1
39
-
-
.
39
-
-
-
43
-
-
-
41
-
-
-
43
-
.
-
41
-
-
-
39
.
-
-
41
-
-
-
43
-
-
-
44
-
-
-
39
44
Surface
tension
dynes/en
62
-
-
-
58
-
64
-
58
-
.
.
65
-
63
-
59
-
51
-
57
.
64
-
60
.
62
-
58
.
59
-
57
-
60
-
62
-
62
-
51
65
Flotation unit
influent (9— i)
GR-Oil
mg/1
87
-
-
.
81
.
-
-
83
.
.
-
106
-
-
-
124
-
-
-
179
-
-
-
116
-
-
-
119
-
-
-
109
-
-
-
ISO
-
-
-
ai
179
IR-Otl
mg/1
96
-
131
-
109
-
100
-
100
-
113
~
126
"
100
~
153
*
580
~
196
-
187
-
144
-
144
~
144
-
113
~
131
-
131
-
196
-
118
-
96
580
GR-Oil
ntg/1
55
70
63
50
47
67
57
98
73
72
77
64
40
49
42
75
30
44
63
46
25
35
49
42
34
40
35
39
32
42
38
36
30
38
44
40
46
32
30
32
25
98
IR-Oil
mg/1
66
-
64
-
54
-
62
-
86
-
74
-
52
-
39
-
40
•
54
-
33
-
44
-
40
-
35
-
40
-
35
-
36
-
35
-
46
-
27
-
27
86
Flotation unit effluent (9—0)
IR-Oil w/sitica qel
Dispersed
•g/1
41
.
35
.
26
-
38
.
52
-
42
-
27
-
14
-
16
.
35
-
12
.
20
-
17
.
14
-
13
-
15
-
13
-
10
-
IS
-
13
-
10
52
SolubTg
25
-
29
.
28
-
24
-
34
-
32
-
25
.
25
.
24
-
19
-
21
.
24
-
23
.
21
-
27
.
20
_
23
.
25
.
31
_
14
-
14
34
Filtered
brine
IR-Oil
mg/1
28
.
31
.
26
-
27
.
31
-
35
.
27
-
27
-
29
-
30
.
28
.
35
.
30
_
29
-
29
-
28
.
34
.
32
.
32
.
29
-
26
35
Surface
tension
dynes/en
70
-
-
-
69
-
.
.
66
.
-
.
69
.
.
.
68
.
.
.
72
_
.
.
67
•
.
-
67
.
.
_
68
_
.
.
68
_
.
-
66
72
Flow rate
Out
.
-
-
.
.
508
S18
1.207
655
693
676
680
121
577
819
742
324
940
442
478
90
454
1.240
1.068
1.049
565
601
1.111
1.046
1.002
488
512
994
862
501
424
777
575
877
545
90
1.240
Skimmings
«3/d
361
361
433
433
192
192
180
122
11
11
8
a
580
667
587
SOB
352
476
715
700
95
162
253
253
253
224
169
190
291
291
102
269
238
293
123
272
282
179
174
172
8
715
-------
dependent on the rate of  skimmings from the flotation  unit.  The wet-oil-tank
pumping  rate was 545 m3/d,  substantially  increasing  the  flow through  the water
treating system when it was on.

Well Test Data

     The well test data provided by the operator are listed in Table  182.
The wells are grouped according to lift method.  The table also shows whether
a well produced all or only part of the ten-day survey period.

                     TABLE  182.  SM130B WELL TEST DATA
Location
Pressure,
kPag
(pslg)
Pressure drop,
point or description
Pressure drop,
kPag
(psig)
Formation
(SIBHP)
Flowing Tubing
Pressure
Low Pressure
.Separator

Desander
CPI
14,480-18,970
(2,100-2,750)
 1,100-5,860
  (160-850)
   600-680
   (87-99)

    40-120
    (6-17)
perforations,
static head,
pipes
chokes,
valves,
pipes

control valve,
pipes
                                       hydrocyclone,
                                       pipes
 8,620-17,870
(1,250-2,590)
   470-5,230
   (70-760)
   520-600
   (75-87)
                            40-120
                            (6-17)
Pressure Drops Through System

     The formation pressures and the flowing tubing pressures for each well
were obtained from well test data.  Table 183 presents the ranges and traces
the pressure drops from the producing formation through the system.  The table
includes only the wells producing water.

     Table 183 shows that the greatest pressure drops occur from the forma-
tion to the chokes, substantial drops occur at the chokes, and more minor
drops from the chokes on.

Chemical Addition

     No water treating chemicals were added on a regular basis on SM130B.
                                     321
-------
                                             TABLE  183.   SM130B PRESSURE DROPS  THROUGH SYSTEM
           Well
Formation
                                        TVO
                                        TT
                        Gas
                        HEW
                                                           Oil
                                          Mater    Lift oas
Uft MS
" jfcfd"
 Pressure, psig
SIBHP       FT
Choke size
 1/64 In.
                                             API gravity
                                                                                                                                 Days of
                                                                                                                               production
           Flowing to Low Pressure Separator
co
ro
f\j
1
2
3
5
7
8
10
11
14
16
20
21
22
25
26
27
28
29
Total (Average)
Gas Lift to Low
6
9
13
Total (Average)
"J" 0
"I," 0.
$i
"j" c;
"J" £Z
"J- 0.
"H," D1
"l|»D
"if" C,
"i;" c;
"I*" D'
"H«" Co
"Ha" 0
"|5" D
"'2 C5
"I* "f
"in *•<;
n |»U,,rO
' 1 ft **O
10 £
Pressure
Wi*
MI u n*
10
5,480
6,140
7.500
5.110
5.160
6.430
5.800
5.100
5.280
7.350
6.930
7.800
6.330
5,620
6,620
8,100
7.360
5.890
-
Separator
8.880
5.800
5.970
-
568
94
199
423
1.727
435
744
370
420
215
384
397
151
329
374
149
287
984
8,250

188
170
116
474
1.526
215
644
1.245
1.108
303
972
1.534
1.506
466
1.200
1,447
675
1.294
1.311
380
768
678
17.272

176
321
249
746
0
721
114
0
0
209
0
0
0
522
0
0
0
0
0
165
0
0
1.731

594
1.708
188
2.490
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
2.650
2.270
2.500
2,420
2.300
2.100
2,550
2.030
2,160
2.320
2.300
2.320
-
2.150
2.150
2.240
2.310
1.830
690
180
420
560
1.100
B50
1.100
520
580
280
630
530
350
600
660
200
520
670
                                                                               186
                                                                               540
                                                                               449
                                                                             1.175
                                                              2.690
                                                              2.550
                                                              2.750
                        200
                        210
                        160
                                                                                       26
                                                                                       32
                                                                                       24
                                                                                       26
                                                                                       26
                                                                                       18
                                                                                       20
                                                                                       28
                                                                                       24
                                                                                       30
                                                                                       24
                                                                                       26
                                                                                       21
                                                                                       26
                                                                                       24
                                                                                       28
                                                                                       21
                                                                                       26
   34
  open
  open
                                                31.9
                                                27.1
                                                29.9
                                                33.0
                                                27.2
                                                18.6
                                                28.9
                                                26.0
                                                26.0
                                                32.
                                                32.
                                                28.
                                                26.
                                                31.
                                                27.1
                                                33.0
                                                39.4
                                                33.6
                                               (29.6)
                                                                                                                 32.0
                                                                                                                 23.0
                                                                                                                 23.7
                                                                                                                (26.2)
                                 All
                                 All
                                 All
                                 All
                                 All
                                1-8,10
                                 All
                                 All
                           1,2.3(1500).4-10
                                 All
                                 All
                                 All
                                 All
                                 All
                                 All
                                 All
                                 All
                                 All
                                                 1-5.6(PM).7-10
                                                 1-5,6(PM).7-10
                                                 1-5.6(PM),7-10
Combined Total (Average)
                                                8,724
                                18.018    4,221
 1.175
               (29.2)
-------
     A foam inhibitor, Dow Corning 200, was added to the produced fluids at
the well manifold.  The foam inhibitor was diluted with diesel to a concen-
tration of 15 percent.  The diluted mixture was fed at a concentration of
3.5 ppmv.

     Methanol was added to the lift gas to prevent hydrate formation.

Observations and Operator Reports

     An effort was made to record any event that could affect effluent oil
content.  The operators were requested to provide information on upsets and
intermittent operational or maintenance procedures and the survey team made
their own observations.

     The flotation unit skimming rate varied widely the first five days,
ranging from 8 to 715 m3/d.  The skimming rate was much more consistent dur-
ing the last five days, ranging from 95 to 293 m3/d.  The skimming rate was
the lowest on Day 3, ranging from 8 to 11 m3/d.  Only one of the flotation
unit cells was skimming on Day 3.  The skimming was substantially increased
on Day 4 when it averaged 586 m3/d and ranged from 508 to 667 m3/d.   This
skimming rate was in excess of the wet-oil-tank pump capacity of 545 m3/d.
In order to maintain the wet-oil-tank level, it was necessary to drain liquid
to the skim sump.  The highest skimming rates occurred on the afternoon of
Day 5.

     Wells were tested in either a test separator or a test treater.  The
test separator separated the production into gas and liquid streams.  The
test treater separated the production into three streams; gas, oil and water,
and metered the streams individually.  The water stream is discharged to the
produced water line from the low-pressure separator to the desander.  Well 9
was tested in the test treater on Day 5 from just after the 1000 sample
period until 1600.  Well 9 produced water at a rate of 272 m3/d (1,708 bpd)
during the test.  This is more than any other well and 40 percent of the total
water production on SM130B.  During the 1300 sample period on Day 5 it was
visually observed that the flow from sample point 8K-i was highly variable
in oil content and at times very high in oil content.

     The platform was shut in on Day 6 at 0600 for pipeline work.  Sampling
was started about 1600, 1/2 hour after flow through the flotation unit
started.  The gas-lift wells, which produced about 59 percent of the water,
began production about the time of the 1800 sample period.  The other two
sample periods on Day 6 were 2000 and 2200.

     Another shut in occurred on Day 9 right after the 1000 sample period.
The flowing wells were shut in for about 1 hour, and the gas-lift wells for
about 2 hours.

     The lift gas injection rate was increased by about 30 percent when pro-
duction was resumed after the shut in on Day 6.  This substantially increased
the water production rate until the lift gas injection rate was decreased on
Day 9 after the 1300 sample period.
                                     323
-------
     Well 8 was taken out of production on Day 9 and gas-lift valves  installed
in preparation for converting the well from flowing to gas lift.  Some  of  the
calcium chloride completion fluid entered the tubing while installing the  gas
lift valves.  The well was opened up on Day 10 during the 0800 sample period,
but no lift-gas piping had been hooked up.  The well had "loaded up" while
it was shut in, and showed a flowing tubing pressure of only 690 kPag with
a correspondingly low flow rate.

     Rains and deck washings result in flow to the skim sump and any oil re-
coved is pumped to the wet-oil tank.  No rains occurred during the test
period.  Deck washings occurred on the afternoon of Day 1, after the  1500
sample period on Day 9,and just before the 1000 sample period on Day  10.

     The skim sump was flushed on Day 5 after the 1500 sample period.   The
flushing included the addition of 19 dm3 of a scale inhibitor, Tretolite
SP36.

DATA PRESENTATION AND EVALUATION

     Comprehensive data tables, summary tables and graphs  for SM130B are
interspersed in the text of this section.

Effluent Oil Content

     Table 181 presents a listing of oil  content test results for the major
sampling points.  Figure 110 presents a plot of GR-Oil  in  and out of the
flotation unit versus time.  Figure 111 presents the same  plot for IR-Oil
content.  The IR-Oil time-indexed plot is  based on two test results per day.
The GR-Oil time-indexed plot is based on one influent and  four effluent test
results per day.

     The tabulated data and time-indexed plots show that the flotation unit
influent is relatively uniform with only one of the 20 IR-Oil contents over
200 mg/1.  The one influent value over 200 mg/1 (580 mg/1)  occurred on Day 5
at the same time as the highest CPI influent value.   The high oil carried
through the flotation unit as a higher than average value.   Day 5 is the day
that Well 9 was being tested in the test treater during the 1300 sample
period.  Well 9 produces 272 m3/d of water and the water from the test
treater is discharged to the line to the desander.  High oil  contents in
the water from the test treater could have contributed to  the high effluent
value.

     The highest flotation unit effluent IR-Oil  was  on Day  3.  The flota-
tion unit skimming rate ranged from 8 to 11 m3/d, far below the average of
280 m3/d.  Only one of the flotation unit  cells was  skimming on Day 3.  The
unit was not skimming enough for effective oil removal  with a dispersed gas
flotation unit.

     No reason is known for the high effluent values on Days 1 and 2.

     The minor elevation in oil content on Day 10 at 0800 may have been
caused by a flow of calcium chloride solution from Well 8.

                                     324
-------
co
ro
en
             aoo-
             TOO-
             6OO-
             50O-
      GR-OIL

       mg/l
             4OO-
             300-
             20O-
              100-
               O-
                                                   T
                                                                  6    '    7    '
10
                                                            DAY
                         Figure  110.   SM130B  flotation unit performance, GR-oil vs time.
-------
CO
              800-
              7OO-I
              6OO-
              500-
       IR-OIL
        mg/l
              4OO-
              3OO-
              EOO-
               100-
                0-
                               2        3        4        5        6    '    7    '
                                                             -DAY

                          Figure 111.  SM130B flotation unit performance,  IR-oil vs time.
8       9    '    10
-------
     The ranges of test results are as follows:
Flotation Effluent GR-Oil
Flotation Effluent IR-Oil
Flotation Influent GR-Oil
Flotation Influent IR-Oil
- 25 to 98 mg/1 ,
- 27 to 86 mg/1 ,
- 81 to 179 mg/1
- 96 to 580 mg/1
     Flotation unit effluent oil content histograms for the two test methods
are presented in Figure 112 and Figure 113.  Figure 114 is a regression plot
of effluent GR-Oil versus IR-Oil.  In comparing oil content test results by
the two methods, it should be remembered that the samples were taken about one
minute apart from a flowing stream.  Therefore, the comparisons include time-
dependent sample differences as well as normal sampling and testing variations.

     Table 184 presents a summary comparison of test results by the two
methods.

     The data presented in Table 184 and the histograms indicate that the
effluent mean oil content is the same by the IR-Oil test method as by the GR-
Oil test method.  The regression plot and the correlation coefficient of 0.91
shown in Figure 114 indicate a significant relationship between results by the
two test methods.

     All  test results for dispersed oil and soluble oil as measured by the
IR-Oil w/Silica Gel test are listed in Table 181.  A summary of these test
results-on the flotation unit effluent is presented in Table 185.

     An average of 52 percent of the oil in the effluent was soluble oil
and 48 percent was dispersed oil.

     Linear regression plots of dispersed oil versus IR-Oil and GR-Oil are
presented in Figure 115.  Extrapolations of the linear regression lines to
zero dispersed oil indicate a residual IR-Oil of 20 mg/1 and a residual GR-
Oil of 21 mg/1 after all dispersed oil is removed.  The mean soluble oil
content of the flotation unit effluent was 25 mg/1.

     The mean soluble oil content of the gravity separator influent was 89
mg/1, significantly higher than the mean of 25 mg/1 of the flotation unit
effluent.

Surface Tension

     All  surface tension test results are listed in Table 181.  The mean sur-
face tension of the gravity separator influent is 60 dynes/cm and of the
flotation effluent is 68 dynes/cm.  The range for flotation effluent test
results was from 66 to 72 dynes/cm.  The linear regression equation for
effluent IR-Oil and surface tension is:

               IR-Oil  = 254-3.0 (Surface Tension)
                    r = -0.32

     A decrease in IR-Oil content of 3 mg/1 is indicated for each 1 dyne/cm

                                      327
-------
           30-
           20-

FREQUENCY   _
    %

           10-
                   i    r
                      20
               iIiIir.

                       ns 40
                       I» 48
                       J :  16
40       60        80
    GR-OIL,mg/I
                                                       100     '  120


Figure 112.   SM130B  flotation unit effluent, GR-oil  histogram.
           30—
           20-

FREQUENCY   _


            10-
                       1    i
               i    t    r     r    r   T-

                        n* 20
                        s s 16
                                40        60       80
                                    IR-OIL,mg/l
                            100
    Figure 113.  SM130B flotation  unit effluent, IR-oil histogram.
                                                                 120
                                 328
-------
CO
ro
         GR-OIL
          mg/l
                     no-
                     IOO-
                     90-
                     80-
                     7O-
60-
                     50-
                     40-
                     30-
                     20-
                      10-
                      0-
                                                             I   I   I  I   T
                                                          I   I
                                I   I
                                GR-OIL'3-9 +0.85( IR-OIL)
                                     r= 0.91
                           I   I
                                    20
                           •40
60.
                                                                I   I
,.80          100          I2O
                                                               lR-OIL.mg/1

                     Figure 114.  SM130B  flotation unit effluent, infrared-gravimetric regression.
-------
                 TABLE 184.   SM130B FLOTATION UNIT EFFLUENT
                        GR-OIL AND IR-OIL COMPARISON
                                          Oil content
                                       GR-Oi1
         IR-Oil
Number of tests, (n)
Mean, (x), mg/1
Minimum, mg/1
Maximum, mg/1
Standard Deviation,(s), mg/1
Number, (n)
Mean of Differences, (&), mg/1
Standard Deviations, (s), mg/1
40
48
25
98
16
20
48
27
86
16
 Paired tests

     20
      3.1
      6.3
                    TABLE 185.   SM130B  SOLUBLE OIL  SUMMARY



Analysis or test
IR-Oil
Dispersed Oil
Soluble Oil
Flotation effluent
Range
mg/1
27-86
10-52
14-34
(9-10)
Mean
mg/1
48
23
25
Proportion
of total ,
percent
100
48
52

increase in surface tension.

Suspended Solids

     The suspended solids tests were run on the low-pressure separator
effluent, the gravity separator influent, and the flotation unit influent
and effluent.  The data are recorded in Table 186 and Table 187 and a
suspended solids summary for SM130B is presented in Table 188.

     The data in Table 188 indicate that more than half of the solids were
Freon soluble.  The data also indicate an increase in Freon insoluble sus-
pended solids across the flotation unit.  The SM130B effluent iron content
was 15 mg/1 which is one of the higher iron concentrations for the produced
brines in this survey.  It is possible that some of the iron was oxidized in
the flotation unit and that there actually was an increase in Freon insoluble
suspended solids across the flotation unit but the precision of the test is
not adequate for a positive answer.
                                      330
-------
       iso-
      140-
       130-
       120-
       110-
       100-
       90-
       80-
TOTAL
 OIL
        6O-
        50-
       4O-
        30-
       20-
        10-
            i  I   1   I  1   I  I   I
                 1  MI   I   n   i  IT
• TOTAL IR-OIU VS  DISPERSED  IR-OIL
TOTAL IRHDIL=20* L2~{ DISPERSED IR-OIL)
r»0.97

• TOTAL GR-OIL VS  DISPERSED  IR-OIL
TOTAL GR-OB. » 2I + I.O(  DISPERSED  IR-OIL)
r » 0.88
                          TOTAL IR-OIL-  DISPERSED  IR-OL
                                                  TOTAL SH-OIL -  DISPERSED  IR-OIL
   I        I  I     I     I   I        I
0            10           20
                                                  i   i - r  i   i  i   r  r  r
                                                  30          40
                                   DISPERSED  IR-OIL, mq/ \
                 Figure 115.   SM130B flotation unit  effluent,
                    total  oil  - dispersed oil  regression.
                                                   I   7
                                                      50
                                        331
-------
                                     TABLE 186.  SM130B  SUSPENDED SOLIDS TESTS
CO
LJ
f\>

Sample tine
Day Hour
01 08
02 08
03 08
04 08
05 08
06 16
07 08
08 08
09 08
10 08
Minimum
Maximum


Total
•9/1
45
52
49
44
58
63
68
56
56
54
44
68
Gravi ty
Freon
soluble
mg/l
45
52
45
43
57
56
62
53
56
54
43
62
separator, in (8K-I)
Freon
insoluble
mg/l
2
]
4
1
0
7
6
3
0
0
0
7
Acid
soluble
•9/1
2
1
4
1
0
1
5
3
0
0
0
5

Fixed
ng/1
0
0
0
0
0
6
1
0
0
0
0
6

Total
»g/l
48
52
42
44
56
40
50
42
44
55
40
56
Flotation unit, in (9— i)
Freon
soluble
mg/l
48
49
42
44
55
37
46
39
44
55
37
55
Freon
insoluble
•9/1
3
3
0
0
1
3
4
3
0
0
0
4
Acid
soluble
•9/1
3
3
0
0
1
3
4
3
0
0
0
4

Fixed
•g/f
0
0
0
0
0
0
0
0
0
0
0
0

Total
mg/l
49
41
51
13
32
21
19
25
27
28
13
51
Flotation unit, out (9—0)
Freon
soluble
mg/l
31
21
37
9
18
21
16
14
26
11
9
37
Freon
insoluble
mg/l
19
20
13
4
14
0
3
11
1
17
0
20
Acid
soluble
mg/l
19
20
13
4
14
0
3
11
1
17
0
20

Fixed
«g/l
0
0
0
0
0
0
0
0
0
0
0
0
-------
                    TABLE 187.   SM130B BRINE TESTS ON LOW PRESSURE SEPARATOR EFFLUENT  (5—0)
CJ
CO
CJ

Suspended Solids

Sample time
Day Hour
01 08
02 08
03 08
04 08
05 08
06 16
07 08
08 08
09 08
10 08
Minimum
Maximum

IR-Oil
mg/1
279
305
253
418
253
59
458
379
340
981
59
981

Temperature
°C
42.0
41.5
41.0
41.0
42.0
40.5
41.5
42.5
42.0
41.5
40.5
42.5

Total
mg/1
56
66
55
49
53
56
62
44
52
56
44
66
Freon
soluble
mg/1
58
55
45
49
45
50
48
44
52
51
44
58
Freon
Insoluble
mg/1
1
11
10
0
7
6
13
0
0
4
0
13
Ac IT
soluble
mg/1
1
10
10
0
7
6
13
0
0
4
0
13

Fixed
mg/1
0
1
0
0
0
1
0
0
0
0
0
1
-------
                 TABLE  188.   SM130B  SUSPENDED  SOLIDS  SUMMARY
                                    	Average suspended solids, mg/1	
Suspended Solids                    5—0        8K-i       9—i          9—0
Total
Freon Soluble
Freon Insoluble
Acid Soluble
Fixed
55
50
5
5
0
55
52
2
2
1
47
46
2
2
0
31
20
10
10
0

     The desander was between sample point 5--0 and sample point 8K-i.  The
mean Freon insoluble solids drop 3 mg/1 between these points.  This is a
relatively insignificant change especially considering the poor precision of
the test.

     Figure 116 presents time-indexed plots of Freon insoluble suspended
solids in the flotation unit influent and effluent, and of flotation effluent
dispersed oil.  All samples were taken at the same time, 0800 each day.  The
linear regression equation for effluent dispersed IR-Oil and effluent Freon
insoluble suspended solids is:

     Effluent Dispersed Oil = 15 +0.77 (Freon Insoluble S.S.)
                          r = 0.43

Filtered Brine

     The filtered brine IR-Oil content of the SM130B effluent was in the
range of 26 to 35 mg/1 with a mean of 30 mg/1.  The filtered brine mean IR-
Oil content of the gravity separator influent was 41 mg/1.

Flotation Unit Performance

     Figure 117 is a regression plot of IR-Oil in and out of the flotation
unit.  The slope of the linear regression line is -0.0063 indicating little
effect of influent oil on effluent oil.

     Figure 118 is a regression plot of flotation unit effluent IR-Oil con-
tent and percent hydraulic loading.  The slope of the linear regression line
is -0.28, indicating a moderate inverse effect of hydraulic loading on
effluent oil.

     The lack of the expected relationships between effluent oil and influent
oil or hydraulic loading may be because of the stable influent oil and the
low hydraulic loading.  All but one of the influent IR-Oil contents were
less than 200 mg/1.  The hydraulic loading was in the range of 1.5 to 20
percent of the design capacity of the flotation unit.
                                     334
-------
                 6O-
                 40-
in
                 30-





     CONCENTRATION
                 20-
                  O-
                                      T	r
T	1	1	1	r
                                                              EFFLUENT  DISPERSED OIL
                                                                  EFFLUENT S.S.
            \/   \
                                                                                           \        /
                                           INFLUENT  S.S.
                                           345         6*7         8    '    9    '10
                                                                 DAY
                         Figure 116.  SM130B flotation unit  Freon insoluble  suspended solids.
-------
CO
co
en
  too—




-  90-
a>
£

-l" 80-

O
I

—  70-
       UJ
       =>  60-
U.
U-
UJ

fc
z
          50-
          4O-
          30-
          20-
          10-
               !  |  |   I  I   I  I   I  I  I  I  I   I  I  I  I  I  I  I   I  I   I  i   I  I   I  I  I  I  I   I  I   I  !   I  I   I  I   I



                         IR-OILoul :49-0.0063 (IR-OILin)
                                r =-0.043
             0 .
                  I  I  I   I  I  I  !
                  IOO          200
I  I  I  I  I
      300
 I   I  I
400
 I
500
 I  I  I   I  I   I  T I
600          700
                                            FLOTATION UNIT INFLUENT IR-OIL, mg/l

                             Figure 117.   SM130B flotation unit  in-out IR-oil regression.
-------
CO
FLOTATION
   UNIT
 EFFLUENT
  IR-OIL.
   mg/l
                   100-
                    90-
                    80-
                    70-
                    6O-
                    60-H
                    40-
                    30-
                    2O-
                    IO-
                         |  I   I  I  I   I  I  I   I  I  I   I  I  I   I  I  I  I  I  I  I  I  I  I  I   I  I  I   I  I  '   I  I  I
                            IR-OIL • 49 -0.28 ( HYDRAULIC LOADING)
                                 r«-0.096
                                         *•  •
                         III  II  I    «  I  I
                                  6           to
                                               i  r
I  I   I  I  I
    25
                                                   15           20
                                                 HYDRAULIC  LOADING, %
           Figure  118.  SM130B flotation unit hydraulic loading - infrared oil regression.
                                                                                            •  •
-------
Gravity Separator Performance

     The sample point for the gravity separator effluent is the same as for
the flotation unit influent (9—i).  The CPI effluent oil  content data are
presented in Table 181.  The CPI effluent mean IR-Oil content was 156 mg/1.

     The results of the susceptibility to separation tests on the CPI influent
are presented in Table 189.  The mean IR-Oil content after 30 minutes of
settling was 155 mg/1.  If the 155 mg/1  is compared to the CPI effluent mean
IR-Oil of 156 mg/1, it indicates that the CPIs are doing the equivalent of
30 minutes of static settling.

     The largest oil drop detected by the particle size test in the oil
treater effluent had a diameter of 120 pm.

Miscellaneous Brine Tests

     All other brine test results for SM130B are listed in Tables 190, 191,
and 192.  The results for the following tests were generally in narrow ranges
for all samples:  temperature, pH, and specific gravity.  These parameters
were therefore not examined for correlation with sample-to-sample variation
in effluent oil content.  These parameters will be discussed in a later
section with respect to variations between platforms.

     Only one ionic analysis test and one sulfate reducing bacteria test per
sample point were run on SM130B.  These tests also are only significant with
respect to comparisons between platforms.

Crude Oil Tests

     All crude oil test results are listed in Tables 193 and 194.  The crude
oil temperature, specific gravity, and surface tension test results all fell
in narrow ranges.

     The viscosity and boil ing.range distribution tests were limited in
number to one and are of primary significance for comparisons between plat-
forms.  Two equilibration tests were run, each at a different oil/water
ratio.  The extraction step was duplicated for each.

     The limited number of tests run on crude oil provide  only a limited
characterization of the crude oil.  Between-platform comparisons will be
presented in Section 17.
                                      338
-------
                TABLE 189.  SM130B SUSCEPTIBILITY TO SEPARATION TESTS ON GRAVITY SEPARATOR INFLUENT
                                         0
                                                           Settling time, minutes
                                                             15
                                    30
fiO
120
       Test Number 1
       Day 3, 1300
       IR-Oil, mg/1
       IR-Oil W/Silica Gel, mg/1
                                 261       174      166     157     153     126     109       270
                                 205        -        92      -       -       -       39
CO
CJ
       Test Number 2
       Day 4. 1300
IR-Oil, mg/1
IR-Oil  W/Silica Gel, mg/1
379       148      148     148     144      122      100        431
301        -        92      -       -       -        39
       Test Number 3
       Day 8. 1500
       IR-Oil, mg/1
       IR-Oil W/Silica Gel, mg/1
                                 597       218      192     174     168     135      113        527
                                 532                157      -       -       -        78
       Average

       IR-Oil, mg/1
       IR-Oil W/Silica Gel, mg/1
                                 412       180      169     160     155     128      107       409
                                 346                114      -       -       -       52
-------
            TABLE  190.  SM130B SUPPLEMENTARY BRINE TESTS
Sample time
Day    Hour
                Temperature,  °C
            8K-1
          9—1
          9-0
                              Specific
                               qravitv
                                9—0
                                                                   (IT
01
02
03
04
05
06
07
08
09
10

Mean
Minimum
Maximum
08
08
08
08
08
16
08
08
08
08
40
40
41.0
40.5
41.0
39.5
41.0
42.0
42.0
41.0

40.9
39.5
42.0
40.0
39.5
40.5
  .5
  .5
39,
40,
37.5
41.0
42.0
41.0
40.0

40.2
37.5
42.0
39.5
40.5
40.0
38.5
40.0
38.5
40.0
42.0
41.0
40.5
                                40.1
                                38.5
                                42.0
6.3
6.3
6.6
6.1
6.0
6.2
6.2
6.1
6.1
                    6.2

                    6.2
                    6.0
                    6.6
1.134
1.133
1.129
1.134
1.129
1.139
1.131
1.134
1.129
1.134

1.133
1.129
1.139
Note:  Sample point identification numbers  (8--1,  9—i,  9--0)  as
       shown on flow diagrams.

(1)    Specific gravity is reported at temperature shown in table
       above.
             TABLE 191. ' SM130B SULFATE REDUCING BACTERIA
  Sample point
                                Bacteria  per  milliliter
 Wet Oil Tank - Bottom
 Low Pressure Separator - Out (5--0)
 Gravity Separator (CPI) - Bottom (8A-B)
 Gravity Separator (CPI) - Bottom (8B-B)
 Flotation Unit - Out (9--0)

 Sample Day and Hour:  05 at 17
                                        10-100
                                        10-100
                                        10-100
                                      1000-10,000
                                        10-100
                                 340
-------
    TABLE 192.  SM130B IONIC ANALYSIS FLOTATION UNIT EFFLUENT
Constituent
Concentration, mg/1
Sodium (Na)
Potassium (K)
Calcium (Ca)
Magnesium (Mg)
Barium (Ba)
Chloride (Cl)
Sulfate (504)
Alkalinity (as HC03)
Iron (Total)
Sulfide (as H2S)
53,325
340
3,560
1,590
160
104,000
< 5
73
15
0.









15
Total Dissolved solids
     Summation
     Gravimetric

Sample Day and Hour:  07 at 15
     163,000
     163,000
                              341
-------
          TABLE 193.   SM1306  CRUDE OIL MISCELLANEOUS TESTS
                                                          (1)
Sample time
DayHour
                Temperature
Specific^
gravity
                           Surface tension
                              dynes/cm
                                                                     (3)
01
02
03
04
05
06
07
08
09
10
08
08
08
08
08

08
08
08
08
39.0
38.5
35.0
31.5
33.0
30.5
33.0
38.0
37.0
34.5
0.863
0.865
0.868
0.869
0.866
0.865
0.866
0.862
0.862
0.863
26
27
25
27
25
27
25
27
25
27
Mean
Minimum
Maximum
                   35.0
                   30.5
                   39.0
              0.865
              0.862
              0.869
                     26
                     25
                     27
Sample  time
Day    Hour
07
15
                   Viscosity at 37.77°C
                 KinematicAbsolute
                centistokes     centipoise
7.87
   6.92
                          Equilibration at 82°C
                       Brine TDS «  163,000 mg/1

Oil/Water  Ratio              4/1          4.4/1
IR-Oil, mg/1                   98(85)       29(22)
IR-Oil W/Silica  Gel,  mg/1       8(3)          3(2)
IR-Oil Filtered  Brine, mg/1    92(98)       31(31)
 (1)   Samples taken from outgoing pipeline.
 (2)   Specific gravity reported for temperature in  table.
 (3)   Surface tension measured and reported  at ambient temperatures
      from 23°C to 25.5°C.
 (  )   Duplicate extraction  on  same sample.
                                   342
-------
           TABLE 194.  SM130B CRUDE OIL BOILING RANGE DISTRIBUTION
                                           Run

Initial Boiling Point, °C                  150
Final Boiling Point, °C                    400
Boiling range, °C                   Percent recovered

Below - 200                                77.4
  200 - 250                                14.0
  250 - 300                                 7.0
  300 - 350                                 1.4
  350 - 400                                 0.2
  400 - 450                                 0.0
  450 - 500                                 0.0

Total                                     100.0
                                     343
-------
                                 SECTION 16

                  MEASUREMENT  OF  OIL  DROP SIZE  DISTRIBUTION
GENERAL
     The purpose of this section is to present a summary of drop-size data
considered most significant for correlation with effluent oil content.

     Drop-size-distribution measurements from photomicrographs were made on
the brine of nine of the ten survey platforms.  The primary sampling points
were the flotation unit influents and effluents.  Some tests were run at
points in the process system ahead of oil/water separators.

     The drop-size measurements were made by a new technique developed for
EPA by Rockwell International.  A complete discussion of the technique
will be found in a separate EPA report.  The system has several unique
facets that will be discussed briefly in this summary.

     The plan called for three test runs involving a total of 400 water
samples at each sample point.  With a few exceptions, this was accomplished.
Brine samples of the photomicrograph!'c test unit effluent were taken for
oil content testing during Phase II only.  These results were taken for
comparison with calculated, dispersed oil contents from the drop-count
measurements.

     A nominal  20,000 photomicrographs were taken of 10,000 brine samples.
The data were reduced to size-number tabulations and histograms,  size-
concentration tabulations and histograms, cumulative size-number  probability
plots, and cumulative size-concentration probability plots.  However,  only
summary tabulations of cumulative percent-by-number, cumulative percent-by-
weight/volume of calculated oil, and assigned oil  content versus  drop  dia-
meter are presented here.

DROP SIZE MEASUREMENT TEST PROCEDURE

     A diagram of the drop-size test system is presented in Figure 119.
Sampling of the pipeline flow, pressure reduction, and bypass sampling were
combined to deliver a fresh turbulent flow dispersed sample to the microscope
cell.  Bypass sampling and pressure reduction were accomplished with an over-
flow standpipe technique.  Whenever possible, the overflow of the standpipe
was maintained at several times the sample cell flowrate.  This insured that
a fresh, well-dispersed sample was available whenever the sample cell  flow-
control solenoid valve permitted flow.  Flow through the microscope cell
during purging was sufficient to replace the cell liquid with a fresh sample

                                     344
-------
                                                        CAMERA
                                                        CONTROL
               FLASH
          SYNCHRONIZATION
     STAND?IPE
     PRESSURE REGULATOR
     SAMPLE
  To 690 kPag
   ELECTRONIC
     CYCLE
   CONTROLLER
VALVE CONTROL
                                                                    VENT
                                                  FLOW CONTROL
                                                    VALVE
                   EXCESS SAMPLE
                       VENT
                          Figure  119.   System  Diagram
of the flowing liquid in the standpipe.  The microscope optics were selected
to produce a nominal photographic magnification of 150X.  A 35-mm camera
equipped with a 250-exposure back and motor drive was connected to the
microscope with an adapter.  Apparent drop movement during photography was
eliminated by the use of a shorter than 5-microsecond-duration electronic
flash illuminator.

     A more complete description of the system may be found in the previously
cited work.

     One of the unique attributes of the system is its ability to measure
the density of the photographed objects as well as their size.  Thus the
system can differentiate between oil drops, gas bubbles, and sand grains.
This is achieved by locating the viewing axis of the microscope in the
horizontal plane rather than the more common vertical plane.  Since the move-
ment of the photographed objects due to the effect of gravity is vertical,
they now move across the viewing plane of the microscope and across the
photographic film.  Time-lapse photography allows measurement of the speed
and direction of this movement.  Application of Stokes1  law principles
permits the calculation of the density of the object.

     The density measurement capability requires interruption of the sample
flow.  In fact, the sample must be stationary for several  seconds  to allow
the turbulence currents to dissipate and movement by  gravity to predominate.
                                     345
-------
The microscope was focused near the top of the cell to detect oil drops that
are lighter than produced brine.  This allows the maximum rise distance be-
fore the drop escapes the opportunity to be photographed.  Calculations based
on Stokes1 law indicate that an approximately 115 vm drop originally located
at the bottom of the cell will not have escaped the photography zone during
the established time cycle of 10 seconds static period and 2 seconds of
photography.

     Sample withdrawal from the pipeline and transport to the system fills
the cell with uniformly dispersed sample and each micro volume has the same
chance of containing drops of any size.  Therefore, although the various-size
drops captured in a photograph were originally in different locations within
the cell, no bias is introduced.

     Generally, brine test samples were taken from flowing streams in pipes
at pressures less than 60 kPag (10 psig).  Sample points were either globe or
ball valves that would accept adaptors for 1.25-cm-diameter Eastman Imperial
Poly-Flo tubing.  These valves were always in the full-open position during
test runs.  The Poly-Flo tubing was kept to a minimum length, consistent with
space and safety considerations.  The Poly-Flo tubing was connected to a
standpipe that maintained a uniform low pressure of about 7 kPag for feeding
the brine to the photographic cell.  Exceptions for individual sample points
are noted in the following paragraphs.

     The standard test sequence for each platform required runs at three
sample points; the input and output of the final water treatment unit, and
the first water knockout tank input.  The typical photographic cycle at each
sample point included 160 time-lapse triads and 250 single photographs.  In
total, 410 individual water samples were examined at each sample point.

     High-oil-content samples such as the feed to the separators were sub-
jected to a preliminary separation to remove the drops larger than 100
micrometers before passing into the microscope cell.  The maximum possible
drop size in the sample is dependent upon the pre-settling time, the fluid.
parameters, and position in the sampling cycle.  The size cutoff is approxi-
mately 40 urn at the fifth water sample and 60 ym at the twentieth water
sample.

     The size and x-y location of the drops in each photograph of a time-
lapse triad were determined by projection of the color transparency on a
digitizing platen.   An operator manually touched the platen stylus to the
sides of each drop.  The data were stored in computer files for calculation
of density, drop-size distribution, log-normal cumulative drop-size distri-
bution, oil content in mg/1, etc.  Calculated dispersed oil  content was
based on the volume of the oil drop and the liquid volume photographed.
The cross-section of this volume was 356 plus the drop diameter by 535 plus
the drop-diameter micrometers, as defined by the photographic film aperture
and the thickness by the depth of focus of the microscope optics.  The system
was calibrated with stage micrometer photographs and the depth of focus
determined from photographs of gel-suspended oil drops.  The apparent depth
of focus and therefore the liquid volume photographed was dependent upon drop
di ameter.

                                     346
-------
     The percent-by-number and percent-by-weight/volume data are all based
on a normalized liquid volume photographed.

SAMPLE POINTS

     Only the flotation influent and effluent samples are discussed.  In all
cases, the best available sample point was used.

Platform SP65B

     Platform SP65B is the only one of which particle size measurements were
not obtained.  Photomicrographs were not obtained on this first platform due
to improper microscope focus.

Platform WD45C

     Separate tests on uncombined streams from the "A" and "B" gun barrels
were used to represent the flotation unit influent.  The samples were taken
from tees in 10-cm (4-inch) water legs.  The sampling pressure was less than
69 kPag.

     The flotation effluent sample point was on the side of the flotation
unit near the outlet.  The pressure was less than 20 kPag.

Platform ST177

     The flotation influent and effluent samples were taken from the side of
horizontal 20-cm (8-inch) lines.  The pressures at both points were less than
12 kPag.

     Special sampling experiments were conducted by inserting probes to the
center of the lines to determine if probes were needed to obtain representa-
tive samples.  The results did not indicate that the probes were necessary.

Platform BM2C

     The flotation influent sample point was on a vertical run of 20-cm
(8-inch) pipe at a point where there was free fall of the flow.  It was
necessary to pinch a downstream valve to obtain a sample.

     The flotation effluent sample point was on a 20-cm (8-inch) elbow.   The
estimated pressure was 7 kPag.

Platform ST131

     The flotation influent sample point was on a 15-cm (6-inch) vertical
standpipe.  The pressure was about 55 kPag.

     The flotation effluent sample was obtained by siphoning from the effluent
settling chamber to a lower deck.  Fifteen meters of garden hose and 2.5
meters of Poly-Flo tubing were used.
                                     347
-------
Platform BDCCF5

     The flotation effluent sample tap was on the side of a 20-cm (8-Inch)
horizontal line 0.3 meter from the tank wall and 2 meters below the fluid
level.  The pressure was about 18 kPag.

     Tests on influent samples were not completed.  The film failed to
advance.  The sprocket holes were stripped for no apparent reason.

Platform SS107

     Both the flotation influent and effluent sample points were on the top
side of the 20-cm (8-inch) horizontal pipes 0.3 meter from the tank wall and
0.5 meter below the fluid level.  The estimated pressures were 5 kPag.

Platform SS198G

     The flotation effluent sample point (Tridair, 9-10) was on the top of
a horizontal 10-cm (4-inch) pipe.  The estimated pressure was 45 kPag.

     The flotation influent sample point (Tridair, 9-li) was on the side of
a horizontal 10-cm (4-inch) pipe.  The estimated pressure was 4 kPag.

Platform EI18CF

     The flotation effluent sample point was on the underside of the flota-
tion unit effluent launder.  The estimated pressure was less than 3 kPag.

     The flotation influent sample point was at the gravity separator out-
let.  A 2.5-cm-diameter probe was inserted 2 meters into a 45-on (18-inch)
horizontal line for sampling ahead of the pump.  The estimated pressure was
50 kPag.

Platform SMI308

     The flotation effluent sample point was on the side of a horizontal
20-cm (8-inch) line ahead of the unit level control valve which was located
on the deck below the flotation unit.  The estimated pressure was 100 kPag

     The flotation influent sample point was in a 20-cm (8-inch) elbow that
went from horizontal  to vertical just ahead of and above the flotation unit.
The pipe was not full at the sample point.  A 1.25-cm probe was inserted into
the horizontal run of pipe to obtain samples.  There was essentially no
pressure at the sample point.

PURPOSE OF TESTS

     The photomicrographic studies were performed to determine the oil-drop-
size distribution at several points in the produced brine treatment system.
The two classes of water treating units surveyed in this program were gravity
separators and flotation units.  Stokes1 law is generally applied in gravity
separator design for removal of all oil drops above a certain diameter.  One-

                                    348
-------
hundred-fifty micrometers (urn) is used in designing API separators.  Any drop
size can be selected and 60 urn is a relatively common criterion for proprie-
tary separators.  The CPI units on the platforms studied were designed to
remove drops above 30 to 40 um.  Thus, knowledge of the drop-size distribu-
tion in the gravity separator effluents may be used to evaluate their per-
formance during routine field operation.  Since the separator effluent is the
flotation unit influent, measurements were made at the flotation unit influ-
ent.  Additional "high oil" measurements were made at the separator influent
to gather data on the small-drop population in the separator feed stock.

     Manufacturers frequently claim oil reductions to less than 10 mg/1 with
gravity separation equipment.  However, removing all oil drops of a certain
size does not necessarily ensure a certain oil content.  It is therefore in-
formative to compare separator performance in terms of measured oil content
and maximum-size drop present.

     Each platform in the survey had a flotation unit to provide the final
treatment step.  These flotation units have the potential for altering the
drop-size distribution toward smaller drops by the shear of pumps or mechan-
ical eductors.  A study of the drop-size distribution in the influent and
effluent of the flotation units may be used to better define this action and
evaluate effectiveness of the several flotation units.

     Mechanically formed oil dispersions in water are often electrostatically
stabilized.  Polyelectrolyte chemicals were added to most of the flotation
units studied to destabilize the dispersions.  The intended purpose of these
chemicals is to reduce the effect of small-drop dispersions on the effluent.
The effectiveness of this treatment may also be evaluated by this study.

DATA PRESENTATION AND EVALUATION

     Sixty-nine drop-size-measurement runs were made on nine different plat-
forms.  A complete tabulation of drop counts by drop size is presented for
each run in Table 195 and Table 196.  Table 197 presents run identification
numbers by platform and sample point for Phase I runs.  Table 198 presents
the same information for Phase II runs.  Table 195 presents Phase I drop
counts and Table 196 presents Phase II drops counts identified by the run
numbers in Tables 197 and 198.

     Tables 199 through 202 summarize the results for the flotation unit
influents and effluents by combining all  data obtained at each sample point.
Table 199 presents cumulative percent-by-number distribution and Table 200
presents cumulative percent-by-Weight/volume oil content calculated from
drop-size tests.  In both cases, the dependence of the photographed volume
on drop diameter has been included in the calculation to normalize the values
to a common sample volume.  Table 201 presents cumulative oil  concentrations
based on the total  oil contents measured by the IR-Oil w/Silica Gel  method
and the percent weight/volume calculated oil  contents from the drop-size-
distribution studies.

     A comparison of the total oil content as calculated from the drop-size
distribution and the values measured by the IR-Silica Gel  method shows that

                                     349
-------
                                                      TABLE  195.   PHASE  I  DROP SIZE DATA
en
o
Run:
SUe.
I
2
3
4
S
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
SO
101
f*
21
208
520
310
193
122
66
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26
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11
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6
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102

41
147
301
174
67
46
33
28
10
9
12
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3
3
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2
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2
3
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1


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103

3
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180
191
104
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32
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20
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193
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108 109 110 111 112 113 114

17 7 IS IB 16 25 45
109 129 77 151 103 184 286
99 79 76 89 67 222 431
22 12 19 12 17 106 134
0 7 8 9 5 50 64
1 5 4 6 4 18 37
5 13 13 17
12 12 12
1 1 262
2 153
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US 116 117

10 15 12
86 97 121
134 171 142
68 66 57
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118 119 120

10 26 32
104 77 183
86 97 188
20 22 35
4 14 22
6 S 10
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121

67
181
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122

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194
209
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872
595
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84
651
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66
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4 5

36 129
181 S58
183 547
42 135
16 62
11 34
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                     xxx Run 1.  55,  1
                     xxx Run 5.  SI,  2; 52, I; 64, 1
                     xxx Run 104, SS. 1
                     xxx Run 121, SI, 1
                     xxx Run 122. 51, 1. 52. 1; 64.  1
-------
                                        TABLE 196.  PHASE II DROP SIZE DATA
CO
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Run: 81 91 82 92
Size. t«
1
2 1
3
4 4 1
5 242)
6 4313
7 1 5 J 3
B 9654
9 2 3 5 5
10 4134
11 2212
12
13 1
14 2 1
15
16
17 1 1
ia
19
20
21 1 1
22 1
23
24
25
26
27
28
29
30
31
32
33
34
35 1 1
36
37
3B
39
40
41
42
43
44
45
46
47
48
49
50

xxx Run 37, 66. 1;B7. 1
xxx Run 47. 54, 1
xxx Run 54, 56. 1
xxx Run 55. 65. 1; 68. 1
xxx Run 56. 89, 1; 97. 1

31

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34
36
88
83
66
51
33
20
13
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3
1
2
3
5

2

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1




1
1






















32

1
12
34
49
99
106
75
54
31
21
17

9
4
2
5
2
1
2
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1
1


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33 34

1
2
33 1
38 1
63
77 2
73 1
78
42 1
32 1
21 1
11
13 1
6
4
6
11
6
3
3

3
2
3
1
1
1

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35 37

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8
1 14
18
36
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1 16
2 16
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xxx





83

3
22
101
123
250
266
214
183
106
73
51
19
29
13
7
13
16
12
5
6

4
2
3
2
2
1
1
4


1
2
1

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1







93



1
1
1
2
1

2
3
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41


6
72
54
90
60
39
23
20
6
9
1
4
1
1


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42


1
15
23
58
51
39
18
11
5
5
1
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1




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43 44

6
3
29
74 5
67 10
112 4
80 5
45 1
33 1
10
9 1
5 2
7
2


2

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1

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1




























45 47

4
1 12
S 68
3 107
3 153
4 138
1 101
63
51
28
1 21
19
17
11
9
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5
9
6

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2
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84

6
10
116
151
215
223
158
86
64
21
23
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94


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51




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53

2
12
53
31
52
33
31
36
30
12
6
7
11
8
10
3
5
3
2
4
3
2
3
1
2
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54




6
14
10
4
8
4
4
3
3
1
2

2
1

2
1
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xxx





55 56

1
12
1 29
2 38
6 54
5 57
3 31
3 27
a 21
5 10
4 6
1 7
10
2 8
3 6
1 6
7
7
4
2 3

2 1
2 2
2
1
1 1
1 1

2

1
1

1
1


1
1

1
1


1
1




xxx xxx





(continued)
-------
                                               TABLE 196.   (Continued)
CO
en
Run:
Site
1
,2
3
4
5
6
7
a
9
10
11
12
13
14
IS
16
17
18
19
20
21
22
21
24
25
26
27
28
29
10
11
12
11
14
15
16
17
18
19
40
41
42
41
44
45
46
47
48
49
50

xxx
XX
XX
XX
XX

«*
XX
XX

XXX

. V*



















































Run
Run
Run
Run
Dun

Run
Run
Run

Run
57
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18
26
40
12
a
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95.
61.
86.
72,
71.
77.
76.
77.
87.
72.
97.
85

2
12
56
51
98
61
56
59
55
11
22
22
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u
12
7
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9
4
5
6
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55.
81.
81.
SI.
52.
li 78
59.
67.
51.
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59. 1
95 61

1 6
12 66
30 81
46 46
74 40
72 IS
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18 7
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19 1
11 1
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i 55. li
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58. li 89.


69. li 8S.
56. li 58.
li 102. 2i

88. 1
55. li 56.
li 78. li

86

6
85
169
105
90
16
11
14
8
S
4
4 >
1
1






1


1







1


















xx»
li 97.


li 90.
li 59.
111. 1


li 58.
85. 2;

71 72

I
7 4
21 61
21 66
26 79
IS 80
7 SI
10 47
4 10
2 IS
14





2
2
2
2



3


1

1
1
1
1
1
2











I

1
1 I

XX
1


li 100
li 61.
i 112.


li 59.
90. 1;

71 74 76

1 1
27 15 60
112 48 71
97 16 54
104 11 34
57 7 14
45 3 6
24 2
14 1
14
14
6
4
10 1
a
S
4
1
3
1



1
1
1
t
2
2


1
1
2
2
2

1




1
1
1


1 1

1
X XXX XXX



. li 112. li 118
li 63. li 65. 1
li 114. li 120.


li 61. 3; 61. 1
100. li 102. 2i

77

1
S
21
41
68
60
46
10
24
IS
6
7
6
4
1
1
1
1
1
|
2


1
1
1
1












1






I



xxx



. 1
i 66.
1


: 65.
111.

87 97

I 4
18 75
198 121
184 90
209 45
152 21
101 9
81 2
48 1
11
29
14
10
19 1
12
9
6
1
5
5



4
|
1
3
2
1
1
1
4
4
4
2
2

1




1
1
1
1

2 2
2
1
xxx xxx




li 69. 1; 71. l; 72. li 75. li



li 66. li 67. li 69. 2; 71. 1;
li 112. 2i 114. li 118. li 120. 1

-------
              TABLE 197.   PHASE I DROP SIZE RUN IDENTIFICATION
dun Platform Samples
101 ST177 90
10Z
103
104
10S
106
107
108
109
110
111
112
46
86
81
87
34
33
85
85
87
33
85
113 W045C 71
114
115
116
117
118
119
120
121
122
37
33
33
38
82
60
77
89
86
01 ST177 340
02 [ 512
03 UD45C 256
04
05
143
254
06 399
Drops
1.651
897
806
658
310
483
366
266
240
207
293
214
1,039
650
396
434
399
• 250
236
604
517
516
2,557
1,586
1,229
486
1,637
1,715
Oil'1'
Sg7T
501
538
366
256
337
147
94
21
16
48
22
12
150
103
46
38
70
24
26
649
309
279
277
35
68
25
406
53
Sample point
High oil - gun barrel inlet
High oil - gun barrel Inlet
Wemco Inlet pipe center sample
Uemco Inlet pipe center sample
Wemco Inlet pipe wall sample
Uemco Inlet pipe wall sample
Uemco outlet pipe center sample
Wemco outlet pipe center sample
Uemco outlet pipe center sample
Uemco outlet pipe wall sample
Uemco outlet wall sample
Uemco outlet pipe wall sample
High oil - "A" Inlet sample
High oil - "A" Inlet sample
"8" outlet stream to Monosep
"8" outlet stream to Monosep
"8" outlet stream to Monosep
"A" outlet stream to Monosep
"A" outlet stream to Monosep
Monosep output (upset condition)
Monosep output (upset condition)
Monosep output (upset condition)
Combined Uemco Input runs
Combined Uemco output runs
Combined "3" stream to Monosep
Combined "A" stream to Monosep
Combined Monosep output runs
Combined Monosep Input runs
       (1)  Oil as calculated from drop counts.
only four of the calculated values were less than  the measured  values  while
12 were higher.  A simple calculation indicates that the  calculated  values
averaged 3 times the measured values.  The largest disparities  resulted  from
samples having either a small number of counted drops or  several  large drops.
Either of these can seriously distort the calculated oil  values since  the oil
drop population is statistically small.  The measured IR-oil  technique samples
3 x 10s times the photographed volume and the statistical distribution becomes
more effective.

Gravity Separator Effluent

     During Phase II of the survey, drop-size tests were  run  on the  gravity
separator effluents of six platforms.  IR-Oil content and dispersed  oil
content were determined analytically on the effluent from the drop-size  test
runs.  Summary listings of the median drop, the largest drop, the  IR-Oil con-
tent and the dispersed oil content are presented in Table 202.

     The median sized drops for the six platforms  had diameters in the range
from 4 urn to 7.5 urn.  There is not a clear relationship between median-drop
size and measured oil content.

     The largest drops in the six effluents were in the range from 28  to
120 urn.  There was no apparent relationship between the largest drop present
                                     353
-------
             TABLE 198.   PHASE II DROP SIZE  RUN  IDENTIFICATION
Run Platform Samples
31 BM2C 410
91
82 SSI
92
31 ST1
32
33
34
35
37
33
93
41 SSI
42
43
44
45
47
34
94
410
07 410
410
31 79
1 31
199
82
75
159
359
157
98G 91
77
210
76
39
267
378
115
51 EI18CF 54
52
53
54
55
56
57
35
95
79
222
57
64
244
23
355
365
61 8QCCF5 32
62
63
36
79
207
368
71 SM130B 77
72
73
74
76
77
37
258
234
77
216
234
574
97 293
Drops
26
32
26
29
468
529
540
9
5
196
1,537
14
388
233
489
29
19
341
1,109
43
91
175
363
72
55
365
158
629
492
281
> 257
27
565
121
507
603
122
250
357
1,231
372
on<:)
557T
4
9
4
11
339
338
257
7
7
298
293
7
133
113
95
14
49
222
108
26
227
205
129
313
282
278
200
161
284
66
59
53
57
37
484
1,093
13
62
213
685
50
Dispersed (2)
oil
(ttg/1
9
42
1
99
168
243
201
10
2
726
204
5
34
34
3
0
0
139
51
3
74
73
32
94
245
229
199
78
189
43
20
21
23
78
65
122
16
14
249
38
15
Sample point
Combined Wemco output
Combined Wemco input
Combined Wemco output
Combined Wemco Input
Wemco Input
Wemco Input
Wemco Input
Wemco output
Wemco output
High 911 sample
Combined Wemco Input
Combined Wemco output
Tridalr input
THdair Input
Trldair output
Trloair output
Tridalr output
High oil sample
Combined tMdair input
Combined tridalr output
Flotation output
Flotation output
Flotation output
Flotation Input
Flotation input
Flotation input
High oil sample
Combined flotation output
Combined flotation input
Monosep output
Monosep output
Monosep output
Combined Monosep output
Wemco input
Wemco input
Wemco input
Wemco output
Wemco output
High oil sample
Combined Wemco input
Combined Wemco output
  (1)  Oil as calculated by drop counts.
  (2)  Dispersed oil as determined ay IR-011 w/Sillca S«l tests.
and measured oil content,  though large drops contribute significantly.

     All oil drops larger  than  50 urn were effectively removed  by  four of the
six gravity separators.  None of the measured IR-Oil contents  were  as low as
100 mg/1 with the lowest being  127 mg/1.

     For most platforms the  same sample point represented the  gravity separa-
tor effluent and the  flotation  influent.   Additional discussion of  flotation
influents (gravity separator effluents)  is presented in the next  subsection.

Flotation Unit  Influents and Effluents

     Previously referenced Table 199, Table 200, and Table 201 present drop-
size-number distributions  and drop-size oil-concentration distributions for
flotation unit  influents and effluents.   The drop-size range covered is from
                                     354
-------
              TABLE  199.   CUMULATIVE  PERCENT-BY-NUMBER DROP SIZE DISTRIBUTION  FOR COMPOSITES  OF TEST RUNS
CO
en
tn


Oil
Percent-by-number of drops with diameter
,n Number Calculated*2' Measured'3' 2 um 5 um
Platforw Samples* ' of drops mg/1 wg/1 I I
Flotation Influent
U045C 399
ST177 340
BM2C 410
ST131 359
BDCCF5
SS107 410
SS198G 378
E118CF 365
SH130B 574
Flotation effluent
WD45C 254
ST177 512
BM2C 410
ST131 157
BOCCF5 368
SS107 410
SS198G 115
EI18CF 355
SMI 308 293
!1) Number of brine

1,715
2.557
32
1.537
-
29
1.109
492
1.231

1.637
1.586
26
14
565
26
48
629
372
samples photographed

53
277
9
293
.
11
108
284
685

407<4>
35
4
7
57
4
26
161
50


.
42
204
.
99
51
189
88

.
-
9
5
28
1
3
78
15

44.5
13.0
0.01
3.8
_
0.01
3.8
6.3
6.2

57
57
9
0.01
25.2
0.01
4.0
5.6
30.3

94.2
85.5
32.5
41.0
„
32.8
54.0
45.0
64.0

95.2
97.1
18
32.5
87.8
15.0
64.0
48.0
94.2
10 um

99.6
98.0
89.0
92.5
.
89.0
97.0
85.6
93.8

98.2
99.63
91
85.0
98.8
93.5
94.8
86.0
99.78
20 um

99.97
99.5
97.3
99.4
_
97.2
99.87
97.3
98.65

99.4
99.94
100.00
100.00
99.85
100.00
99.42
98.45
99.78
30 um

100.00
99.92
99.0
99.88
_
99.0
100.00
99.0
99.05

99.8
99.98
_
_
99.94
.
99.42
99.9
99.78
40 um


99.97
100.00
99.98
_
100.00
.
99.55
99.5

99.95
99.98
_
_
99.98
.
100.00
100.00
99.78
equal or less than
60 um 100 um >100 pm


100.00
-
100.00
- -
-
-
99.95 100.00
99.77 99.94 100,00

99.95 100.00
100.00
-
-
99.98 100.00
_
.
-
100.00
Lart-
>A
drops
>40 >60

0
3
0
1
-
0
0
11
41

8
1
0
0
1
0
0
0
3

0
0
0
0
-
0
0
2
26

1
0
0
0
1
0
0
0
0

drop
u

25
55
35
49
-
35
28
97
120

64
41
17
16
81
14
35
32
59
for drop counts.
2) Oil as calculated from drop counts.
3) Dispersed oil as
measured by IR-011 w/Silica Gel
tests
on the brine
effluent
        (4)
from particle-size test equipment when the partlcle-slze-distribution test was run.
Test run during upset conditions.
-------
                                       TABLE  200.   CUMULATIVE  OIL CONTENT BY  DROP  SIZE  IN  PERCENT
LO
cn






on
Platform
Flotation
UD4SC
ST177
BM2C
smi
BDCCF5
SS107
SSI 986
EI18CF
SM130B
Flotation
U04SC
ST177
BM2C
ST131
8DCCF5
SS107
SS198G
EI18CF
SM130B
, . . Number
Samples* ' of drops
Influent
399
340
410
359
-
410
378
365
574
Effluent
254
512
410
157
368
410
115
355
293

1,715
2.557
32
1.537
-
29
1.109
492
1,231

1.637
1.586
26
14
565
26
48
629
372
Calculated* 'Heasured'' 2 urn
»g/l ng/l ~T~

53
277
9
293
-
11
108
284
685

407«>
35
4
7
57
4
26
161
50


_
42
204
-
99
51
189
88

.
_
9
5
28
1
3
78
15

5
0.42
0.01
0.03
_
0.01
0.06
0.02
0.02

1.3
7.3
0.12
0.01
0.85
0.01
0.07
0.04
1.1

Percent
S urn

44.5
17.5
3.0
6.0
-
3.0
14.5
1.9
1.7

6.6
37
2.0
3.0
17.4
2.8
11.4
4.2
17.5

of oil
10 \w

76
37.5
27.5
42.8
-
26.0
70.8
10.0
6.8

11.5
55
67.0
48.5
37.5
80.0
31.0
27.5
24.8

in drops
20 JM

92.5
60
46.0
76.2
-
43.0
93.0
31.0
12.4

27.2
70
100.00
100.00
46.3
100.00
47.0
71.0
26.0



with diameters equal or
30 urn

100.00
79
57.0
90.0
-
65.2
100.00
43.0
15.5

48.8
80
-
.
51.5
.
47.0
97.8
26.0
40^*

.
91
100.00
97.0
-
100.00
-
56.0
22.8

74.0
B7
-
.
58.0
.
100.00
100.00
26.0
60 m


100.00
.
100.00
-
-
-
79.5
37.0

94.3
100.00
-
.
58.0
-
.
.
100.00

less than'2^
100 urn >100 urn

.
.
.
.
-
.
.
100.00
65.5 100.00

100.00
-
-
.
100.00
-
-
-
-


Large
drops
>40 >60

0
3
0
1
-
0
0
11
41

8
1
0
0
1
0
0
0
3

0
0
0
0
-
0
0
2
26

1
0
0
0
1
0
0
0
0

Largest
drop
u

25
55
35
49
-
35
28
97
120

64
41
17
16
81
14
35
32
59

          (1)
          III
          (4)
Number of brine samples photographed for drop counts.
Oil  as calculated from drop counts  in milligrams per Ifter.
Dispersed oil  as measured by 1R-OI1 w/SiUca Gel tests on the brine effluent
from the particle-size test equipment when  the particle-slze-distrlbutlon test was run.
Test run during upset conditions.
-------
                            TABLE 201.  CUMULATIVE ASSIGNED OIL  CONTENT  DISTRIBUTION
                               BY DROP SIZE GROUPS IN COMPOSITES OF  TEST RUNS(l)
CO
en
-vl
Oil
... Number Calculated'3'
Platform Samples' ' of drops mg/1
Flotation Influent
UD45C 399 1.715
ST177 340 2.557
BM2C 410 32
ST131 359 1.537
BOCCF5
SS107 410 29
SS198G 378 1.109
E118CF 365 492
SM130B 574 1,231
Flotation Effluent
W045C 254 1 .637
ST177 512 1.586
BM2C 410 26
ST131 157 14
BOCCF5 368 565
SS107 410 26
SS198G 115 48
EI18CF 355 629
SM130B 293 372
53
277
9
293
.
11
108
284
685

407<5>
35
4
7
57
4
26
161
50
(1) The cumulative oil concentration data in this
Assigned
concentration of oil in drops w/dia equal or less than "'
Measured14' 2 um S um
»g/l mg/1 mg/1

.
42
204
.
99
51
189
88

.
.
9
5
28
1
3
78
15

.
0.0
0.1
-
0.0
0.0
0.0
0.0

.
-
0.0
0.0
0.2
0.0
0.0
0.0
0.2
table were calculated
total analytically determined dispersed oil concentration
data reported in Table 200.

S2) Number of brine samples photographed for drop
3) Oil as calculated from drop
4) Dispersed oil as measured by
from the particle-size test
was run.
counts.

counts.

IR-011 w/SIUca Gel tests on

.
1.3
12.2
.
3.0
7.4
3.6
1.5

.
.
0.2
0.2
4.9
0.0
0.3
3.3
2.6
10 um
ig/T

.
11.6
87.3
.
25.7
36.1
20.4
6.0


.
6.0
2.4
10.5
0.8
0.9
21.5
3.7
by multiplying
by the percentage



the brine



effluent
|0j«

.
19.3
155.4
-
42.6
47.4
58.6
10.9

.
.
9.0
5.0
13.0
1.0
1.4
55.4
3.9
the
30 um
"ig/T

.
23.9
183.6
.
64.5
51.0
81.3
13.6

.
_
_
_
14.4
.
1.4
76.3
3.9

40 um 60 um 100 um 100 urn
TSgTr Tg/T lOtfr mg/i

...
42.0
197.9 204.0
...
99.0
...
105.8 150.3 189.0
20.1 32.6 57.6 88.0

.
...
.
. - -
16.2 16.2 28.0
...
3.0 - -
78.0
3.9 15.0

Large
drops
>40 >60
0
3
0
1
-
0
0
11
41

a
i
0
0
1
0
0
0
3

0
0
0
0
-
0
0
2
26

1
0
0
0
1
0
0
0
0

Largest
drop
u
25
55
35
49
-
35
29
97
120

64
41
17
16
81
14
35
32
59

concentration




























equipment when the particle-size-distrtbution test











(5) Test run during upset condition.
-------
                    TABLE 202.   GRAVITY SEPARATOR EFFLUENT DROP SIZE-OIL CONTENT COMPARISON
CO
en
00



Platform
BM2C
SS1986
SM130B
ST131
EI18CF
SS107
Gravity
separator
type
Corrugated plate
Corrugated plate
Corrugated plate
Gun barrel
Skim tank
Oil treater^
Drop
Median
urn
6
4.5
4
5.5
5
7.5
diameters
Largest
pm
35
28
120
49
97
35
Oil
IR-Oil
mg/1
131
127
138
285
219
153
(2\
con tent v '
Dispersed oil
mg/1
42
51
88
204
189
99

            (1)   This  separator was not  specifically a water treatment  separator, but was a  dual
                 purpose  unit  for  removing water from crude oil.
            (2)   Oil contents  are  based  on an average of three test runs measured on the effluent
                 from  the particle size  test runs.
-------
2 to 120 ym.  The largest drop detected had a diameter of 120 ym.  The
cumulative number distribution data are presented in percent for listed urn
sizes in Table 199 to permit comparison between platforms.  The cumulative
concentrations in Table 200 are also in percent for ready comparison.

     The cumulative concentration data in Table 201 are presented in milli-
grams per liter since the amount of oil present in small drops is the most
important question to consider.  The concentration data in Table 201 are
based on two assumptions.  First, that the best available data on total dis-
persed oil content are those from the IR-Oil w/Silica Gel tests and second,
that the best available data on drop-size distribution are those from the
drop-size tests.

     Table 203 presents an overall drop-size oil-concentration distribution
summary.  This table presents median drop sizes, total dispersed oil concen-
trations, and cumulative number and concentrations listings for 10-wm and
20-ym oil drops.  The 20-ym comparison point was chosen because in flotation
effluents 98 to 100 percent of all drops had diameters equal or less than
20-ym, and in flotation influents 97 to 99 percent of all drops had diameters
equal or less than 20 urn.  The 10-ym point was chosen because it is between
the 20-ym point and the median drop size for all test runs.  The following
discussion is in reference to Table 203.

     The median drop sizes for flotation influents were from 2 to 7.5 ym.
The range for effluents was from 1.5 to 7 ym.  The maximum difference for
any platform in median drop size between the influent and the effluent was
less than 2 ym.  Median drop size is not a distinguishing feature between
influents and effluents.  A comparison of median drop sizes and dispersed
oil content does not indicate that median drop size is a distinguishing fea-
ture between high-oil and low-oil content brines within the range of 1 to
204 mg/1 of dispersed oil as shown in the table.

     Six of nine flotation effluents had 99 percent or more of the drops with
diameters of 20 ym or less.  Ninety-eight percent of drops 20 ym or less was
the lowest percentage for any platform.  For comparison, five of eight flo-
tation influents had 99 percent or more of the drops 20 ym or smaller.  The
lowest percentage was 97 for three influents.  There is a general pattern of
higher percentages of 20 ym and smaller drop in effluents than in influents.
However, the percentage was higher for the influent than for the effluent of
two platforms.

     Additional comments and conclusions are referenced in Tables 199, 200,
and 201.  Comments are also included on the following data printouts pre-
pared for each particle-size test run:

     Drop size/Drop number histograms.
     Drop size/Oil concentration histograms.
     Drop size/Drop number cumulative plot on probability scale chart.
     Drop size/Oil concentration cumulative plot on probability scale chart.

     These data plots are not included in this report but will be presented
in a more comprehensive final  report on the oil-drop-size counter.

                                    359
-------
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                                                     Lk. r^ oo u o

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                                                                           o


                                                                           ft
                                                                           4>
                                                                           4-1


                                                                           01
                                                                     s
                                                                     3
                                                                     i
                                                                      >    *»
                                                                     J   .-"

                                                                     8  - =
                                                                     O  VI 01 .
                                                                     "*  5 S
                                                                      P.  ri
                                                                      §  o.«-
                                                                      ^  13s
                                                                      
-------
Following are specific conclusions and comments:

1.  Oil-drop size distributions were obtained from photomicrographs for
    both flotation influents and effluents.  These generally followed a
    log-normal distribution for any one fluid sample.

2.  Dispersed oil concentrations were calculated from these distributions
    using the number and diameter of drops.  These calculations are
    strongly influenced by a statistically small number of large drops.

3.  The calculated dispersed oil concentrations generally compared poor-
    ly with the measured concentration obtained from the IR-Oil w/Silica
    Gel technique.  Most often, the calculated concentration was too
    high, but values which were too low were also obtained.

4.  The poor comparison between calculated and measured oil content can
    be attributed in part to statistical uncertainty in the small number
    of large drops.  The remaining conclusions concerning drop-size must
    be tempered because of this poor agreement.

5.  Finely dispersed oil with drop sizes from 2 to 10 urn were observed
    in both the influent and effluent of all the platforms studied.
    The percent-by-number of these drops was high, between 85 to 99
    percent.  The calculated weight/volume percentage concentrations
    of such drops were quire variable, between 7 and 80 percent.  The
    amount of oil in drops, 10 urn or less, in flotation effluents is not
    significantly different from that in flotation influents.  Part of
    this variability may be due to uncertainties in the exact number of
    large oil drops.  The data, as analyzed, are not sufficient to
    identify the variations caused by shearing droplets or by upstream
    processing.

6.  Only a statistically small number of oil drops over 20 to 40 um
    were observed in gravity separator effluents (flotation influents).
    With the exception of Platform SM130B, the gravity separator
    effluents contained only a statistically small number of drops over
    60 ym.  The above conclusion is consistent with various manufactur-
    ers'  design criteria for gravity separators including gun barrels,
    skim tanks and CPI units.  These are often designed to remove drops
    in the range of 40 to 100 ym.

7.  Dispersed oil  droplets with sizes ranging from 20 to 60 um were
    present in small  numbers in all  the flotation influents studied.
    The percent-by-number of such  drops varied from 0.03 to 2.8 per-
    cent.   The calculated weight/volume percent of such drops varied
    from 7 to 54 percent of the dispersed oil content.   While such
    calculations are subject to considerable error, oil  droplets in
    the size range of 20 to 60 um  usually contribute a  significant
    amount of the dispersed oil content in flotation influents.

8.  A tentative observation is that gas flotation appears to remove
    most oil droplets in the size  range of 20 to 60 um, which are not

                                361
-------
     removed by gravity separation.   Gas flotation may be less effective
     in removing drops in the size range of 2 to 10 ]an, but this has
     not been proven.   Drop size data which is more consistent with
     measured oil contents would be  needed to verify this latter result.

 9.   Flotation units are generally effective in removing dispersed oil
     from brine.  The total dispersed oil  content of four of seven
     platforms was less than 10 mg/1.

10.   The two platforms, EI28CF and SM130B, that did not employ a flota-
     tion chemical were highest and  third  highest in flotation effluent
     dispersed oil.

11.   The platform, 8DCCF5, that had  the second highest flotation effluent
     dispersed oil content had the highest flotation unit hydraulic
     loading of platforms for which  oil content tests were run with
     particle-size tests.
                                 362
-------
                                 SECTION 17

                            DISCUSSION OF RESULTS
GENERAL

     An important objective of the program was to identify factors affecting
brine effluent oil content.  Platforms were selected representing a wide
spectrum of water treating equipment, producing characteristics, and physical
properties of produced fluids so that these factors could be studied.  The
single factor considered most important was brine treatability.  The opera-
tor's preliminary estimates of treatability were generally confirmed by the
soluble oil and susceptibility to separation test data collected during the
survey.

      Each platform surveyed has been described in a separate preceding sec-
tion and the test results for each have been presented.  The purpose of this
section is to make comparisons between platforms.

     In the individual sections, all  test data were reported, and sample-to-
sample variations were discussed.  In this section, comparisons between plat-
forms are presented primarily in terms of averages.  The effluent oil contents,
the performance of gravity separators and flotation units, and the effect of
system and operational factors on effluent oil content are compared.

     The approach to presenting the comparisons is first to present listings
describing the properties of produced fluids, the production systems, and the
water treating units and then to examine the more important parameters in
more detail.  The descriptive information has been presented in individual
platform sections and is again listed here for ease of comparison.

PRODUCED FLUIDS

     There were significant differences in the ratios and the properties of
the brine and crude oil  of the ten platforms.  A summary listing of properties
is presented in Table 204.

     The range for water cuts was from 10 percent to 91 percent.  The brine
total dissolved solids range was from 80,500 to 203,000 mg/1.  The crude
oil API gravity range was from 25.8 to 41.9.  Significant differences can be
noted for most of the properties listed in Table 204.

     The parameters considered most important with respect to brine effluent
oil content are discussed in following subsections.
                                     363
-------
                                                  TABLE  204.   PROPERTIES  OF PRODUCED FLUIDS
to


Water Cut, Percent
Brine Properties
pH
Total Dissolved Solids, mg/1
(Gravimetric)
Temperature, °C /,»
Specific Gravity)}!
Surface Tension,1 'dynes/cm
Crude Oil Properties
API Gravity 8 15.6'C
Temperature, °C ,,.
Specific Gravity}!}
Surface Tension/ 'dynes/cm
Viscosity 9 37.8°C, Centipoise
Boiling Range, °C
Initial Boiling Point
Final Boiling Point

SP658
35

6.9
105,000

38.6
1.086
67

29.5
36.0
0.865
30
8.24

150
480

VTO45C
64

7.0
80,500

39.7
1.073
60

25.8
36.9
0.890
30
20.21

150
485

ST177
47

6.3
203,000

36.1
1.151
67

36.8
32.9
0.842
30
3.47

150
480

BH2C
27

6.6
114.000

45.0
1.093
60

34.2
39.1
O.B31
25
3.41

150
4(0
Platform
ST131
32

6.3
138,000

22.6
1.129
61

36.7
20.0
0.842
25
2.85

150
480

BDCCF5
91

6.7
108,000

40.9
1.095
61

31.4
31.8
0.863
28
8.26

150
480

SS107
87

6.6
112,000

48.2
1.095
63

35.2
44.5
0.825
26
3.71

150
500

SS198G
10

7.1
114.000

31.1
1.106
66

34.0
30.2
0.848
27
5.24

150
500

fhecf
90

6.3
162.000

38.2
1.140
57

41.9
35.1
0.810
26
2.44

150
480

SHI 308
19

6.2
163,000

40.1
1.133
68

29.2
35.0
OJJ65
26
632

150
400
Percent recovered
Below - 200
200 - 250
250 - 300
300 - 350
350 - 400
400 - 450
4SO - 500
500 - S50
49.1
10.4
14.6
14.5
5.1
5.4
0.8
0.2
29.7
12.4
21.9
21.2
6.2
6.8
1.4
0.4
42.8
10.5
19.3
13.0
6.6
6.9
0.8
0.2
61.1
22.6
13.2
2.4
0.6
0.1
0.0
0.0
61.7
22.6
8.8
1.6
0.3
0.1
0.0
0.0
45.9
24.5
22.5
5.6
1.3
0.2
0.0
0.0
38.2
24.3
25.5
6.3
3.0
2.0
0.7
0.0
48.4
27.2
17.5
3.2
1.6
1.2
0.6
0.0
37.1
23.4
27.3
7.5
2.1
0.3
0.0
0.0
77.4
14.0
7.0
1.4
0.2
0.0
0.0
0.0
           Note:  Brine properties are based on tests on flotation unit effluents.  Crude oil properties are based on tests on crude oil  samples taken after all
                 treatment steps on the platform

           (1)    Specific gravity and surface tension test results are reported for approximately  the listed temperature.
-------
PRODUCTION PROCESS SYSTEMS

     There were significant differences in the production systems of the ten
platforms.  No two were exactly alike.

     Limited comparative descriptions of the platforms are presented in
Table 205 with respect to percent of gas lift, gas/oil/water separators,
gravity separators and flotation units.  The range for percent of gas lift
was from 0 to 99.8 percent.  There were some common elements, but also some
differences, in the gravity separation systems of all platforms.  Five diff-
erent flotation unit design variations were included in the survey.  No two
chemical addition programs were the same.

     Descriptions of water treating gravity separators and flotation units
are presented in the next following subsection.

WATER TREATING UNITS

     The gravity separators and flotation units were described for each plat-
form in preceding sections.  A summary comparison of these units is presented
in Table 206.

     Three platforms had CPI gravity separators.  Three had skim tanks.  Two
had gun barrels, and two did not have a gravity separator specifically for
the purpose of treating brine prior to flotation.  Sketches of the various
types of gravity separators were presented in the individual  platform
sections.  There was a wide range of hydraulic loadings.  The range of load-
ings for tank-type separators was from 8.2 to 84 (m3/d)/m2.  For CPI sepa-
rators the range was from 10.2 to 580 (m3/d)/plate pack.

     One platform had a dissolved gas flotation unit.  Five had four-cell
mechanically-dispersed gas units.  One had a four-cell  hydraulically-dispersed
gas unit.  One had a three-cell hydraulically-dispersed gas unit, and two had
one-cell hydraulically-dispersed gas units.  The mean hydraulic loadings
varied from less than 2 to 70 percent of the manufacturer's recommended
loading.

EFFLUENT OIL CONTENT

     There were significant differences in the flotation effluent mean IR-Oil,
GR-Oil, dispersed oil and soluble oil contents of the ten platforms.  The  test
data are listed in Table 207 in the order of increasing IR-Oil  content.

     The effluent oil content means varied from 7.6 to 77 mg/1  by the GR-oil
method and from 15 to 106 mg/1 by the IR-Oil method.   There were also signif-
icant differences in the oil content standard deviations for the different
platforms.  The mean IR-Oil was higher than the mean  GR-Oil for all  platforms
except SM130B for which the means were the same.

     The effluent mean soluble oil  range was from 10  to 61 mg/1.  Since gas
flotation will remove little if any soluble oil, the  soluble oil content
may represent a lower limit of treatability.  The data confirm that there  are

                                      365
-------
                                       TABLE  205.  PRODUCTION PROCESS SYSTEMS
CO
CT>
Oi
Comparison Factor
Portion of Water
Gas Lifted, Percent
High Pressure Separators

Medium Pressure Separators

Low Pressure Separators

Oi) Treater


Water Treating Gravity
Separators

flotation Unit

Down-Hole Chemical Addition
Paraffin Inhibitor
Corrosion Inhibitor
Platform Chemical Addition
Foam Inhibitor
Biocide
Oemulsifier
Scale Inhibitor
Flotation Aid

SP65B

99.8
_

One.
2-phase
One.
3-phase
One. Chen-
Electric

One.
Skim Tank

Weroco.
Mechanical

No
No

No
Continuous
Yes
No
Yes

U045C

1.7
_

.

Three,
2-phase
Two.
Gun Barrels

None


Monosep.
Hydraul ic

Yes
Yes

Yes
Batch
Yes
No
Yes

ST177

0
One.
2-phase
_

One,
3-phase
Off
Platform

One.
Gun Barrel

Weroco.
Hydraul ic

No
No

Yes
Batch
Yes
No
Yes

BH2C

58
One,
2-phase
.

One.
3-phase
One, Chen-
Electric

One.
2-pack
CP1
Wemco.
Mechanical

No
No

No
No
Yes
No
Yes
Platform
ST131

21
One.
2-phase
.

One.
3-phase
Off
Platform

One,
Gun Barrel

Uanco.
Mechanical

No
No

No
No
Yes
No
Yes

BDCCFS

88
_

.

Four.
2-phase
Two.
Heater
Treaters
Two,
Skim Tanks

Monosep.
Hydraul ic

No
No

No
Batch
Yes
Yes
Yes

SS107

62
One.
2-phase
„

Two,
2-phase
One.
Gravity

None


Wemco.
Mechanical

No
No

No
No
Yes
Yes
Yes

SS198G

0
One,
2-phase
_

One.
2-phase
One, Chen-
Electric

One,
1-pack
CPI
Tridair,
Hydraul ic

No
No

No
No
Yes
Yes
Yes

EI1BCF

90
Two.
2-phase
.

One.
3-phase
One,
Heater
Treater
One,
Skim Tank

PCE.
Dissolved

No
No

No
No
No
No
No

SM130B

59
„

.

One.
3-phase
Off
Platform

Two,
2-pack
CPI's
Uecico,
Mechanical

No
No

Yes
No
No
No
No
         (1)  In lift gas.
-------
                                       TABLE 206.  WATER TREATING  UNITS
to
a\


Gravity Separators
Type
Number

Hydraulic Loading. m3/d
(w3/d)/m2
Inlet Distribution(l) ,n
Short Circuiting Potential1"
Flotation Unit
Trade Name
Number of Cells
Method of Gas Dispersion
Design Capacity, n3/d
Average Loading. (2) m3/d
Average Loading, Percent of Design
Overflow Rate Per Cell,
(m3/d)/«z
Froth Flow, Percent of
Average Loading
Recycle Flow, Percent of
Average Loading

SP65B

Skim Tank
One

955
21
Good
Low

Wemco
4
Mechanical
6,135
655
11
202

46

None

WD4SC

None


_
.
_
-

Monosep
1
Hydrau) Ic
981
691
70
135

10

570

ST177

Gun Barrel
One

919
31
Fair
High

Wemco
4
Hydrau) ic
2.460
849
35
300

8

510

BM2C

CPI
One.
2-pack
1.160 ...
(Sao)1*'

-

Uemco
4
Mechanical
4.090
995
24
255

17

None
Platform
ST131

Gun Barrel
One

241
8.2
Fair
High

Wemco
4
Mechanical
1.638
111
7
60

117

None

BOCCFfi

Skin Tank
Two

(c\
945 \l\
27 t5)
Poor
High

Monosep
1
Hydraul ic
3.180
1,890
59
177

<1

670

SS107 SS198G

None CPI
One.
1-pack
l°-2(4\
(10.2)
.
-

Wemco Tridair
4 3
Mechanical Hydraulic
2.460 795
733 9.2
30 1.2
260 8.1

19 11

None 39.000

EllBCr"

Skin Tank
One

7.949
84
Fair
Moderate

PCE
1
Dissolved
10,900
2.920
27
59

0.5

None

SH130B

CPI
Two,
2-pack
970 (4)
(242)1*'
-
-

Wemco
4
Mechanical
6.135
690
11
207

41

None
11) Subjective opinion based on review of separator configuration.
2) Based on effluent flow
!3) Based on total surface area of
4) Cubic meters per day per plate
(5) For each of two skim tanks.









all separation cells.
pack.

















-------
        TABLE 207.  PLATFORM FLOTATION  EFFLUENT OIL CONTENT COMPARISON
Platform
SS107
SS198G
BOCCF5
ST131
BM2C
SM130B
EI18CF
M045C
ST177
SP653
GR-011,
X
7.6
18
26
12
22
48
52
63
64
77
l
(s)
(5.2)
(9.2)
(6.9)
(13)
(6.7)
(16)
(24)
(95)
(74)
(73)
IR-011
X
15
36
36
37
39
48
76
81
95
106
. mo/1
(S)
(3.7)
(7.8)
(8.3)
(19)
(4.2)
(16)
(38)
(109)
(103)
(99)
Dlsosrsed
X
1.6
5.7
26
5.9
4.9
23
63
66
92
38
oil . TO/1
(s)
(1.5)
(7.7)
(8.6)
(13)
(5.1)
(13)
(30)
(106)
(126)
(80)
Soluble
X
13
31
10
28
36
25
13
30
21
61
oil. mq/1
(s)
(2.7)
(2.7)
(2.3)
(3.1)
(4.1)
(4.7)
(13)
(32)
(13)
(15)
Soluble oil,
Fraction of IR-011
t
87
86
28
76
92
52
17
37
22
58
    Note: Some numbers do not check because of rounding. Two significant figures have been retained In all
        numbers below 100.

        x « Mean
        (s) * Standard Deviation
significant differences  in  trealability of brines from different  platforms.

     Table 208 presents  an  empirical  rating of brine treatability as  judged
by mean soluble oil content.

     The last column  in  Table  207 illustrates that most of the oil  in some
brines was soluble and  in other  brines was dispersed.  Dispersed  oil  in  rela-
tion to treating unit performance is  discussed in the next following  sub-
sections.  Additional discussion of soluble oil in relation to water  cut is
presented in a following subsection.

     There were significant negative  correlations between effluent  IR-Oil
content and surface tension sample-to-sample for each platform.  A  summary
listing of mean surface  tension  and linear regression slope and correlation
coefficient is presented in Table 209 for all platforms.

FLOTATION UNIT PERFORMANCE

     There are significant  differences in the amount of dispersed oil  remain-
ing in the ten flotation effluents.   The platforms are listed in the  order of
increasing mean dispersed oil  in Table 210.  The range for the means  was from
1.6 to 92 mg/1.  Units reducing  dispersed oil to the lowest levels  can be  con-
sidered most effecitve.

     Four factors of  potential  significance to flotation unit performance  are
listed in Table 210.  These are  influent oil concentration, hydraulic loading,
flotation chemical addition rate, and the type of flotation unit.   There are

                                      368
-------
                 TABLE 208.  SOLUBLE OIL TREATABILITY  RATING
Platform
Treatability
Effluent mean
 soluble oil
content, mg/1
BDCCF5
SS107
EI18CF
Mean
ST177
SM130B
ST131
WD45C
SS198G
Mean
BM2C
SP65B
Mean
Easy
Easy
Easy

Medium
Medi urn
Medium
Medium
Medium

Difficult
Difficult














10
13
11
12
21
25
28
30
11
27
36
11
48


TABLE 209. SURFACE
TENSION SUMMARY




Platform
SP65B
WD45C
ST177
BM2C
ST131
BDCCF5
SS107
SS198G
EI18CF
SM130B
Mean
surface
tension
67
60
67
60
61
61
63
66
57
68
Linear regression

Slope
-6.9
-17.8
-11.6
-0.4
-1.24
-2.94
-6.1
-4.5
-3.2
-3.0
Correlation
coefficient
-0.96
-0.87
-0.70
-0.5
-0.65
-0.73
-0.92
-0.68
-0.84
-0.32

significant design and operation differences for all platforms.  A single pre-
dominant factor that determines flotation effectiveness in removing dispersed
oil has not been identified by simple bivariate data analysis.  Therefore,
special features of each platform are discussed separately.

                                     369
-------
                    TABLE 210.   PLATFORM  FLOTATION UNIT PERFORMANCE COMPARISON
Flotation effluent
dispersed oil
Platform
SS107
BM2C
SS198G
ST131
SH130B
BOCCF5
SP65B
E11BCF
UD45C
ST177
*?T
1.6
4.9
5.7
5.9
23
26
38
63
66
92
"9/1
(1.5)
.(5.1)
(7.7)
(13)
(13)
(B.6)
(BO)
(30)
(106)
(126)
Flotation Influent
tjt»l IR-oil
Bfl/1
215
158
130
386
156
113
170
222
1169
432
JiL
•3/1
(49)
(65)
(39)
(199)
(105)
(15)
(147)
(210)
(3409)
(394)
Hydraulic
loading
1 of design
24-31
18-39
 Hydraulic gas dispersion
      (Oj
Dissolved gas
(1)  estimated mean.
-------
     Platform SS107 had the lowest mean dispersed oil content of 1.6 mg/1.
The influent oil loading was moderate and uniform, and the hydraulic loading
uniform and not over 31 percent of design.  Chemical addition was intermediate
with respect to other platforms at 14 ppmv.  The flotation unit was a four-
cell unit with mechanical gas dispersion.  There was a general pattern of
consistency, but none of the listed factors explains why the oil content was
lowest.  Platform SS107 was one of only two that did not have a water-treating
gravity separator.

     Platform BM2C had the second lowest mean dispersed oil content at 4.9
mg/1.  BM2C was very similar to SS107 with respect to the type of flotation
unit and the consistency of the listed operational parameters.

     Mean dispersed oil was reduced to 5.7 mg/1 on SS198G in a three-cell
hydraulically-dispersed gas flotation unit.  However, the mean hydraulic
loading was less than 2 percent and the chemical addition rate averaged 255
ppmv.  These parameters are non-typical and limit the comparability of the
performance of this unit to the others.

     The four-cell mechanical dispersed gas unit on ST131 reduced the mean
dispersed oil content to 5.9 mg/1.  The influent oil was third highest of
the ten.  However, the maximum hydraulic loading was only 12 percent and the
chemical addition rate was 126 ppmv which is high compared to that of most
other platforms.

     On SM130B, mean dispersed oil was reduced to 23 mg/1 in a four-cell
mechanical unit.  Influent oil loading was moderate and the maximum hydraulic
loading only 20 percent.  Flotation chemical was not added.

     On BDCCF5, mean dispersed oil was reduced to 26 mg/1 in a one-cell  unit
with hydraulic gas dispersion.  The influent oil loading was the lowest and
most consistent of any platform.  The hydraulic loading was second highest at
59 percent and chemical addition relatively low at 5 ppmv.

     On Platform SP65B, mean dispersed oil was reduced to 38 mg/1  in a four-
cell mechanical unit.  Influent oil content was moderate, hydraulic loading
only 11 percent, and the chemical  addition rate was 17 mg/1.  Reference to
Section 6 shows that two high oil  content values occurred corresponding to
high influent values, when chemical feed was off.  If the two high effluent
values are excluded, the mean effluent dispersed oil is 14 mg/1.

     On EI18CF, mean dispersed oil was reduced to 63 mg/1 in the only dis-
solved gas flotation unit included in the survey.  Flotation chemical  was not
added.  Some influent oil contents were high, over 500 mg/1.  The  high
influent values were associated with high effluent values.  These  factors may
account for a comparatively high dispersed oil content.

     On Platform WD45C, mean dispersed oil was reduced to 66 mg/1  in a one-
cell unit with hydraulic gas dispersion.  This unit had the highest hydraulic
loading in the survey with a maximum of 75 percent of design.  There was not
a separate water-treating gravity  separator in the system.  Excursions in
effluent oil  content occurred, usually associated with high influent values.

                                     371
-------
     On Platform ST177, mean dispersed oil in the effluent was 92 mg/1.   For
six days of the survey, this platform was in a general  upset condition as
operations were recovering from the effects of a hurricane.  For this reason,
the test results from this platform cannot reasonably be compared to the
others.

     In summary, because of the many differences between platforms, it is not
possible to make quantitative conclusions on the factors most important to
flotation unit performance.  Therefore, considering the information in this
section and in the individual platform sections, general conclusions are
presented concerning flotation unit performance.

     High influent oil content excursions over 500 mg/1 usually, but not al-
ways, had a marked effect on effluent oil content (see  influent and effluent
oil content data plotted in Figures 8, 9, 21, 22, 33, and 34).  An influent
oil content below 300 mg/1 appears desirable.  Some lightly loaded units may
handle more than this.

     Oil content usually increased when chemical feed was interrupted.
Chemical addition is employed to enhance oil separation.  The selection  of
flotation chemicals and addition rate were not part of  this study.

    Hydraulic loading was not evaluated comprehensively during the study
because most units operated at relatively low and uniform loadings, and
problems were experienced in flow monitoring.  Also, simple statistical
analysis did not demonstrate a substantial.general correlation between
flotation influent oil content and effluent oil content, except when influent
excursions occurred.  Intuitively, hydraulic loading and oil/loading are
important parameters which could be studied by more complex data analysis
and/or additional testing.

GRAVITY SEPARATOR PERFORMANCE

     There were significant differences in oil content  of gravity separator
effluents.  See Table 211.  There were significant differences in the oil
separation rates of gravity separator influents and effluents from different
platforms as measured by the susceptibility to separation test.  There was a
general relationship between separation rate measurements and gravity sepa-
rator effluent oil content.  For some platforms, other factors were more
important in separator performance than separation rate as measured by the
tests.

    Three platforms had CPI separators, three had skim tanks, two had gun
barrels and two had no gravity separator specifically for water treating.
The different types of separators were described in the individual platform
sections.

    The principal purposes of the gravity separators in the water handling
systems are (1) to remove a large percentage of the oil from the water up-
stream of the flotation units, and (2) to protect the flotation units from
the effects of slugs of oil which might enter the water handling systems as
a result of upsets in the production processing systems.  Where appropriate

                                     372
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                                  TABLE  211.   PLATFORM GRAVITY  SEPARATOR  PERFORMANCE COMPARISON
OJ
-^
PI at fora
BOCCFS
SS198G
SM130B
BH2C
SP65B
SS107
EI1BCF
ST131
ST177
M045C
Water
treatment
separator
type
Skin
Tank
CPI
CPI
CPI
Skin
Tank
None<2>
Skin
Tank
Gun
Barrel
Gun
Barrel
W
(1) Separator influents were sampled If
were sampled when influent samples
Settling tests
Effluent
ID-oil, «g/l
5 (s)
113 (15)
130 (39)
156 (105)
158 (65)
170 (147)
215 (49)
222 (210)
386 (199)
432 (394)
1169 (3409)
Settling tine
5 Bin
«9/l
103
209
169
219
311
119
151
851
210
59
a sample tap was available.
could not be taken.
120 nil
»9/l
S3
117
107
128
128
86
39
239
100
54
Other
Sample (
> point
9-1
8-1
BK-i
8— i
5A30
9-1
8—1
8-1
9—1
9— i
points and
1
1) Hydraulic loading A
Tank CPI
(»3/d)/»Z («3/d)/plate pack
27
10
242
580
21
120
84
8.2
31
38
effluents
Brine/oil
specific
gravity
.232
.258
.268
.262
.221
.270
.330
.287
.309
.,03

Brine
temperature
°C
41.1
36.5
40.9
45.6
33.0
49.2
39.9
22.8
36.6
40.2

             !2) Gravity separation was in an oil  treater with the primary function of separating water from oil.
             3) Gravity separation was in two gun barrels with the primary function of separating water fron oil.
-------
 sample points were available for both the influents and effluents of the
 gravity separators, the data in the tables of major brine tests show that all
 the gravity separators were successful in reducing the oil  contents of the
 waters.  An exception occurred on Days 5 and 6 on EI18CF when the IR-Oil
 content of the effluent from the skim tank was higher than  that of the in-
 fluent.  This might have been caused by the skim tank's operating at too
 low a level so that previously separated oil was swept from the tank by the
 inlet flow.  The oil content in the effluent decreased appreciably on Day 7
 after the level of the tank had been raised (see Table 163  and Observations
 and Operator Reports, Section 14).

      Major upsets, i.e., incidents in which the IR-Oil content of samples
 from the influent to the gravity separator was so high it was reported in per-
 cent instead of mg/1, occurred on ST177 and ST131.  In both cases, the gravity
 separators prevented slugs of oil from reaching the flotation units for
 several days (see Tables 63 and 94 and Observations and Operator Reports,
 Sections 8 and 10).  Both of these platforms are equipped with gun barrel
 type gravity separators.

     Less severe upsets occurred on SP65B and SM130B.  The maximum IR-Oil
 content for the gravity separator influent on SP65B was 96,000 mg/1; the
 upset condition persisted for two days.  The upset condition on SM130B was
 of much shorter duration, i.e., only one "abnormally" high  value was reported
 for the IR-Oil content of the gravity separator influent.  This maximum value
 was 11,549 mg/1.  Although these high values were reflected by unusually high
 oil contents in the flotation unit influent samples, the gravity separators
 on both platforms retained nearly all the oil (See Tables 17 and 181 and
 Effluent Oil Content, Section 6 and Observations and Operator Reports, Sec-
 tion 15).  SP65B is equipped with a skim tank as the gravity separator, and
 SM130B with a CPI.

     The platforms are listed in Table 211 by increasing order of the mean
 IR-Oil contents of the gravity separator effluents.  Standard deviations for
 the oil contents are also given.  The temperature and the difference in
 specific gravity of the brine and oil are given for each separator.  For a
 general comparison of loading, the cubic meters per day per square meter are
 shown for the tank separators, and the cubic meters per day per plate pack
 for plate separators.  There are appreciable variations in  all listed para-
 meters .

     The means of the IR-Oil content of the gravity separators' effluents
varied from 113 to 1,169 mg/1, and the standard deviations from 15 to 3,409
mg/1.  The gravity separators, in increasing order of the means of the
effluent oil contents, were a skim tank, the three CPI separators, a skim
tank, a dual purpose oil treater, a skim tank, two gun barrels and a dual
purpose gun barrel.  The three CPI separators produced relatively uniform
 oil contents, as did the two skim tanks with hydraulic loadings below 30
 (m3/d)/m2.  The mean values of the IR-Oil contents of the gun barrel effluents
 were higher than those of the skim tanks and CPIs but, as discussed above,
 both platforms with gun barrels experienced major upsets of several days'
 duration during the surveys.


                                      374
-------
     This survey has demonstrated that gravity separators will remove sub-
 stantial amounts of oil from produced brines and protect the flotation units
 from slugs of oil which enter the water handling system as the result of up-
 sets in the production processing systems.  The superiority of one type of
 gravity separator over the other types was not demonstrated.

     Table 211 also lists mean oil contents for 5-minute and 120-minute settl-
 ing periods from the susceptibility to separation tests.  These data show
 there are wide variations in settling rates between platforms.  After 5
 minutes of settling, the lowest mean oil content was 59 mg/1 for WD45C; and
 the highest, 851 mg/1 for ST131.  After 120 minutes the lowest was 39 mg/1
 for EI18CF; and the highest, 239 mg/1 for ST131.  Curves representing the
 data from the susceptibility to separation tests are shown in Figures 120 and
 121.  These curves also illustrate the differences in separation rates for
 different oils and brines.

     There is a general relationship between gravity separator effluent oil
 content and rate of separation of oil as indicated by settling tests.  This
 is illustrated by the data in Table 212.  For seven of eight platforms, a
 high proportion of separator effluent IR-Oil tests fall in the range est-
 ablished by 5-minute and 120-minute settling rate tests (susceptibility to
 separation).  Thirty-one percent of the oil content: tests of ST131 were in
 the range,  even though influent oil contents were frequently in the range of
 percent rather than mg/1.  Only 8 percent of the oil content test results of
 SS107 fell in the range, and none of those of WD45C.  These two platforms do
 not have a separate water treating gravity separator and the results are
 presented for comparison only.

     The settling tests indicated the lowest separation rate for Platform
 ST131.  The temperature of the brine was lower for this platform than for
 any other.

     Platform WD45C had the smallest oil/water specific gravity difference.
 Contrary to expectations the oil separated the easiest based on the 5-minute
 test.   Factors  other than  gravity  difference predominated.

 BRINE SOLUBLE OIL

     Four tests were used as indicators or measurements of soluble oil.  They
 were the IR-Oil  w/Silica Gel test, the IR-Scan test, the equilibration test,
 and the filtered brine test.  The tests indicated there are variable amounts
 of soluble components in brines from different platforms.

     The IR-Oil w/Silica Gel test results have already been presented and
discussed as soluble oil.  When the program plan  was developed water cut was
proposed as a parameter to examine for correlation with soluble oil, the
theory being that brine from new wells with a low water/oil  ratio would be
high in soluble oil  components.

     Table 213 presents a listing of mean soluble oil in increasing order.
 The corresponding water cuts for the produced fluids are also listed.  For
 the first eight platforms listed, the water cuts are exactly in inverse order

                                       375
-------
      400-
       375-
       350-
       325-
       300-
       275-
       250-
       225-
IR-OIL
mq / I
       200-
        175-
       150-
       125-
        100-
        75-
        50-
             o
20
60
  40       60        30
SETTUN6 TIME, MINUTES
                                                             too
                                                 120
                Figure 120.  Susceptibility  to  separation.

                                    376
-------
      300-
     280-
      260-
      240-
     220-
      200-
      180-
IR-OIL
 mg/I
      160-
      I4O-
      120-
      100-
       80-
       60-
      40-
      20-
           T    1     I     I     I
                    I    I     I
                             I     I     I
            \
            0
20
40
 I
80
       I     I    I

SETTLING TIME, MINUTES
100
120
               Figure 121.  Susceptibility to separation.


                                  377
-------
   TABLE 212.  SEPARATOR EFFLUENT OIL  CONTENT SETTLING TEST COMPARISON
Platform
BOCCF5
SS198G
SM1308
BM2C
SP65B
SS107
EU8CF
ST131
ST177
W045C
Water
treatment
separator
type
Skim
Tank
CPI
CPI
CPI
Skim
Tank
None'2'
Skim
Tank
Gun
Barrel
Gun
Barrel
None'3'

Mean
igTT
113
130
156
158
170
215
222
386
432
1,169
Gravity separator IR-011
Proportion in settling'1'
Test range
Percent
35
90
80
66
60
8
SO
95
31
0
Settling test ranged)
IR-011 content
5 min it
mo/1 i
121
237
192
261
331
136
163
1,259
271
68
!0 min
mj7T~
43
101
100
105
113
56
38
168
85
49
   (1)  The settling test range 1s reported as the highest 5-m1nute settling test result and the lowest
      I20-m1nute test result.
   (2)  Gravity separation was 1n an oil treater with the primary function of separating water from oil.
   (3)  Gravity separation was 1n two gun barrels with the primary function of separating water from oil.
                    TABLE 213.   SOLUBLE OIL AND WATER CUT




Platform
BDCCF5
EI18CF
SS107
WD45C
ST177
SM130B
ST131
SS198G
BM2C
SP65B
Mean
soluble
oil
mg/1
10
13
13, .
18U)
21
25
28
31
36(2)
57

Water
cut
%
91
90
87
64
47
19m
18
10
27
35

(1)  This mean does  not  include  the three highest soluble oil  test values
     which appear  inconsistent.
(2)  This mean does  not  include  the two  highest test  values  which  appear
     inconsistent.
(3)  The water cut does  not include one  well  producing only  water.

                                          378
-------
to the soluble oil.  The two highest mean soluble oil values do not follow the
precise order of the others.  The calculated least squares linear regression
equation is:

               Soluble oil, mg/1 = 40 - 0.29 (water cut, %)
                               r = -0.67

A significant correlation is indicated of decreasing soluble oil concentra-
tion with increasing water cut.

     The API gravity, as a parameter indicating lighter or heavier oil, was
examined for correlation with soluble oil.  Brine total dissolved solids and
pH were also examined for correlation.  These parameters do not show a
significant relationship to soluble oil by simple bivariate analysis.

     IR-Scan tests were run on brine Freon extracts only during Phase I.
Carboxilic acid groups were indicated to be present in the extracts from all
three platforms.  The data was qualitative and did not indicate whether the
acid groups were from the produced fluids or the addition chemicals.

     As explained in Section 5, the filtered brine test requires additional
development to establish it as a reliable indicator of soluble materials or
treatability.

     The equilibration test provides an indication of soluble components in
brine of the same order of magnitude as the IR-Oil w/Silica Gel test.

     For Phase I, two equilibration tests were run on the crude oil from each
platform".  Duplicate tests were run with oil/water ratios of 4/1 and a brine
TDS of 100,000 mg/1.  For Phase II, two tests were run for each platform but
they were not duplicates.  Both tests were run at the formation-brine TDS.
One was run at a 4/1 oil/water ratio.  The plan was to run the other test at
the formation water-cut ratio.  This was done for all platforms except
SS198G which was unintentionally run at a different oil/water ratio.

     The equilibration test results are listed in Table 214.   The number of
tests is too limited for definitive conclusions.   Following are general
comments.

     The equilibration tests show that for all  individual  test runs some oil
is partitioned into the brine.  The duplicate tests during Phase I all  checked
reasonable well.  For two Phase I platforms, the equilibration IR-Oil  and
the platform mean soluble oil  checked reasonably well.  The third platform
did not match well in this respect.

     Considering Phase II tests at formation oil/water ratio, the equilibrated
brine soluble oil checked closely with mean soluble oil for platforms BDCCF5,
SS107, and SM130B.

     The equilibration test on SS198G was run at the wrong oil/water ratio.
Two-hundred-fifty-five ppmv of flotation chemical  was added to the brine on
SS198G.  Although not proven,  this may have contributed to the mean soluble

                                     379
-------
                                                   TABLE 214.    EQUILIBRATION TESTS
CO
CO
o
Platfon*
Phase 1
SP65B

U04SC

ST177

Phase II
BH2C

ST131

BDCCF5

SS107

SS19BG

EI18CF

SMI 306

Brine
Produced
-SgTT-

141,000

121.000

211.000


105,000

131.000

112.000

106.000

116.000

164.000

163.000

70S
Test
ig/T

100.000
100.000
100.000
100.000
100.000
100.000

105.000
105.000
131.000
131.000
112.000
112,000
106.000
106.000
116,000
116.000
164.000
164.000
163.000
163.000
Oil/water ratio
Produced

1.09/1

0.57/1

1.15/1


2.64/1

4.4/l<2>

0.10/1

0.15/1

8.6/l<3>

0.11/1

4.3/1

Test

4/1
4/1
4/1
4/1
4/1
4/1

4/1
2.64/1
4/1
4.4/1
4/1
0.1/1
4/1
0.15/1
4/1
0.15/1
4/1
0.11/1
4/1
4.4/1

IR-oll
-igTT

50
56
137
125
31
17

8
8
35
35
90
15
12
14
12
9
11
9
92
26
Equilibrated
Ift-oil w/
silica gel
«9/l

.
-
«
-
.
~

6
6
23
23
10
3
8
2
6
4
6
5
6
2
brine
Soluble oil
«9/l

_
-
.
-
.
•

2
2
12
12
80
12
4
12
6
5
5
4
36
24
PUtfora nean
soluble oil
•9ft


61

30

21


36

28

10

13

31

13

25
            (1)  Sumwtion net hod.
             !2)  Not Including one well  that produced only water.
             3)  Based on netered oil and water flow. Days 5-9.
-------
oil which is higher than that of the equilibrated brine.

SUSPENDED SOLIDS TESTS

     As discussed in the individual platform sections, significant correla-
tions between suspended solids and brine oil content were not identified.
Also as discussed in Section 18, the precision and accuracy of the field
survey tests were questionable.  For these reasons, indepth between-platform
comparisons of suspended solids in relation to oil content are not presented.
A cursory review of the data did not indicate a significant relationship.

SULFATE REDUCING BACTERIA

     The sulfate reducing bacteria counts in brine effluents were 100 per
milliliter or less for all  platforms except ST131.  Counts up to 1,000,000
per milliliter were obtained on some tank bottom samples and sump effluent
samples.

     None of the survey platforms was observed to have a black-water problem
as may be caused by iron sulfide and other sulfide compounds.  For this
particular survey, sulfate reducing bacteria did not appear to relate to
effluent oil content.
                                    381
-------
                                 SECTION 18

                          SPECIAL TEST EVALUATIONS
GENERAL
     Test method development was not included in the Program when it was
initiated.  The Program was to be carried out using established test methods.
As the survey proceeded, it became apparent that the suspended solids test
and the filtered brine test were deficient and some test evaluation studies
were needed.  In addition, some special tests were run to determine the
effect of acidification on the IR-Oil test.

SUSPENDED SOLIDS TESTS

     The suspended solids test procedure used closely followed ASTM and EPA
procedures, which are essentially the same.  A full description of the proce-
dure is presented in Appendix A.

      A brief review of the steps in the procedure follows.   Brine was
drawn through a tared millipore filter directly from the sample taps on.the
platforms; the filter was washed with 50 ml of deionized (D.I.) water, the
filter was returned to the laboratory, dried and weighed to  obtain Freon
solids; the filter was washed with Freon, dried and weighed  to obtain Freon
soluble solids; the filter was washed with HC1, dried and weighed to obtain
acid soluble solids.  Blanks consisted of clean filters exposed to prefiltered
brine and the various wash steps.  Numerical blank adjustments were developed
for the water wash step, the Freon wash step, and the acid wash step.

Nature of Problem

     A significant number of suspended solids test results were negative
which is not reasonable.  Several clean filters were exposed to artificial
brine (100,000 mg/1 TDS).  These synthetic brine blanks were highly variable
and indicated variable amounts of salt were being retained by the filters.
These blank determinations are reported in Table 215.  The substantial range
in these blanks implies poor precision since a comparable range would be
expected in the samples.

     The blanks actually used for the tests were determined  on prefiltered
brine from each platform according to the ASTM procedure.  These blanks are
reported for information only in Table 216.
                                     382
-------
        TABLE 215.  SUSPENDED SOLIDS BLANKS ON ARTIFICIAL BRINE
                                                               (1)

Filter
number
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
Average net
Equivalent
mg/1
Average
Minimum
Maximum
Standard
Tare weight
of filter,
grams
.1229
.1231
.1219
.1217
.1222
.1214
.1223
.1234
.1238
.1225
.1219
.1224
.1128
.1122
.1130
.1134
.1119
.1124
.1113
.1121
change
/ r
concentration, ^
Deviation
Net gain(+) or
After brine
and DI water
wash, B
+.0169
+.0111
+.0058
+.0100
+.0080
+.0113
+.0136
+.0114
+.0125
+.0177
+.0110
+.0096
+.0163
+.0090
+.0084
+.0081
+.0085
+.0118
+.0055
+.0068
+.0107
1 \
!)
+ 10.7
+ 5.5
+ 17.7
3.5
loss(-) of filter weight, grams
After Freon
wash, B
+.0009
+.0011
+.0002
+.0005
+.0006
0
+.0007
0
+.0008
+.0004
+.0007
+.0004
+.0005
+.0008
+.0006
+.0004
+.0003
0
+.0002
+.0006
+.0005
0.5
0.0
1.1
0.3
After acid
wash, B.
a
-.0067
-.0047
-.0017
-.0039
-.0047
-.0048
-.0065
-.0042
-.0050
-.0096
-.0037
-.0022
-.0065
-.0027
-.0031
-.0025
-.0034
-.0039
-.0008
-.0011
-.0041
- 4.1
- 1.1
-9.6
2.1

(1)   Brine strength  =  100,000 TDS.
(2)   For one liter samples.
                                    383
-------
                  TABLE 216.  SUSPENDED SOLIDS BLANKS RUN
                        ON PLATFORM SPECIFIC BRINE
Net gain(+) or loss(-)
of filter weight, grams
Platform
SS107
BM2C
ST131
SM130B
SS198G
BDCCF5
EI18CF
EI18CF
EI18CF
Tare weight,
of filter,
grams
.1341
.1329
.1326
.1338
.1329
.1369
.1319
.1314
.1294
Vol. of
brine,
ml
250
250
250
250
250
250
250
100
50
After brine
and DI wash,
B
+.0080
+.0083
+.0051
+.0083
+.0075
+.0046
+.0343
+.0318
+.0321
After Freon,
wash,
Bo
-.0001
0
-.0001
+.0001
+.0001
0
+.0001
-.0006
+.0003
After acid
wash,
Ba
-.0010
-.0016
+.0002
-.0008
-.0015
+.0001
-.0126
-.0150
-.0143

Filter Wash Blank Experiments

     Because washing with 50 ml of deionized water did not provide stable
blanks, it was assumed that the same washing procedure was not adequate for
test samples.  Any retained salt would be reported as suspended solids.  If
the salt were then removed by the acid wash step, it would be reported as
acid soluble solids.  Experiments were conducted to determine an adequate
water-wash volume.

     The procedure for the water-wash experiment was as follows:  A 50 ml
sample of brine from each platform was filtered according to the TSS procedure
and the filter dried and weighed.  This filter became the "unfiltered" sample
for that platform.  The same brine was then filtered again and the filter
dried and weighed.  This filter became the "prefiltered" sample for that
platform.

     Each filter was then washed with 50 ml of deionized water according to
the TSS method, dried  and weighed.  This process was repeated five times and
the dry weight recorded after each wash.  After five washes, the experiment
was stopped.  The filter weights seemed to be leveling near the tare weight.
More important, however, the filters were becoming ragged around the edges
and would undoubtedly continue to lose weight after each handling as glass
fiber material was lost.
                                     384
-------
     The experimental washing results are presented in Table 217, and in
Figure 122.  It is apparent that the first 50-ml wash leaves substantial
salt on the filter and the weight of the filter tends to stabilize after five
50-ml washes.

     It was very interesting to notice that in every case the weight gain
was greater in the prefiltered sample than in the unfiltered sample.  This
experiment was done with a mi Hi pore filter holder which supports the fiber
filter with a fine glass frit.  It is very unlikely, therefore, that any
filter material became suspended in the brine after the first filtering.
Also, a sample of brine was aerated prior to filtering and the same
phenomenon was exhibited.  At this point it was determined that to pursue
this problem further would become very expensive and should not be done as
part of this program.

     It was demonstrated that a 250-300 ml wash volume would be much more
effective in removing the water soluble salts.  It also appears that some of
the variability in this method is the result of damage to the filters and
subsequent loss of filter material.  After the filters have been in and out
of the filter holder several times the edges are noticeably worn even when
the greatest care is taken in handling them.  If a more durable filter mate-
rial were used and/or a better holder developed, the method would be more
reliable.

FILTERED BRINE TEST

Nature of the Problem

     When the IR-Oil content of filtered brine was compared to unfiltered
brine, the oil content of the filtered brine was consistently higher for
some platforms.  Analysis indicated that the filtered brine IR-Oil  of
effluents exceeded the regular IR-Oil when the dispersed oil was less than
15 mg/1.  Platforms SS107, BM2C, ST131, and SS198G provide examples of this.
The mean filtered brine IR-Oil was 30 mg/1 higher for SS198G.  The filtered
brine IR-Oil results of effluents were less than the regular IR-Oil results
when the dispersed oil exceeded about 15 mg/1.  Platforms WD45C, BDCCF5,
EI18CF, SM130B, SP65B, and ST177 are examples of this.

     The filtered brine IR-Oil was consistently less than the regular IR-Oil
for gravity separator influents and effluents.

Saved Filter Experiments

     When the standard IR-Oil tests were run, significant staining was
observed of the filters used to clarify the Freon before the absorbance
measurement.  The survey team was requested to determine how much oil was
being retained on the filters when the standard IR-Oil tests were run to
explain lower IR-Oil results.

     The filters from IR-Oil tests run on four of the platforms were retained.
The amount of oil on the filters was determined later by Freon extraction in
the laboratory and IR-absorbance.  Most of the retained filters were from

                                     385
-------
             TABLE 217.  SUSPENDED SOLIDS BLANK WASHING STUDIES
                        Net gain in filter weight relative to tare weight, gms
           Filter tare   AfterAfterAfterAfterAfter
Platform   weight, gms  1st wash   2nd wash   3rd wash   4th wash   5th wash
Initial
SS107
BM2C
ST131
SS198G
EI18CF
BDCCF5
SM130B
Initial
SS107
BM2C
ST131
SS198G
EI18CF
BDCCF5
SM130B
Brine Not Prefiltered
.1345
.1336
.1366
.1315
.1309
.1305
.1360
Brine Prefil
.1322
.1363
.1317
.1336
.1320
.1323
.1364
.0118
.0036
.0192
.0130
.0238
.0137
.0219
tered
.0240
.0501
.0284
.0254
.0347
.0211
.0379
.0065
.0025
.0122
.0090
.0159
.0086
.0117

.0132
.0306
.0200
.0142
.0240
.0122
.0211
.0052
.0014
.0088
.0067
.0130
.0063
.0093

.0087
.0059
.0131
.0092
.0150
-.0020
.0117
. .0044
.0015
.0080
.0049
.0117
.0055
(1)

.0050
.0046
.0096
.0061
.0088
-.0020
.0072
.0050
.0013
.0069
.0045
.0110
.0051
(1)

.0039
.0041
.0096
.0046
.0066
-.0023
.0062

Note:  Fifty milliliters of deionized water was used for each wash.

(1)  Filtered damaged.
 IR-Oil tests but a few were from GR-Oil tests.  All test results were reported
 in milligrams per liter of the original brine sample for comparability.

     The filters were retained in two ways.  Some were placed in a bottle with
 100 ml of Freon immediately after completion of the field test.  Others were
 placed in bottles that did not contain Freon.  These filters were air dried
 in the laboratory before extraction with Freon.  Blanks were run on unused
 filters.

                                     386
-------
  £ .0200-
  o
O -r
UJ *- IIMCII rsrocn      ^-»«-
                       UNF1LTERED
              I
              1st
             VWXSH
                        2nd
                       WASH
WASH
 4th
WASH
 5tt>
 WASH
                                BM2C
              1st
             WASH
                        2nd
                       WASH
 I
 3rd
WASH
 r
 4tt)
WASH
 I
 3»h
WASH
     Figure 122.  Suspended solids water wash blank studies


                          387
-------
     .0300-
   o
®5
Hi 52 .0200-1
o -r
ui o
5 <
-------
     .0300-
   £
   a
     .0200-
Si
0 x
tug
  Ul
  u.
  <
      .0100^
                                                     ST13I
              •PREFILTERED

UNFILTERED-
                     1st
                    WASH
         2nd
         WASH
  I
3rd
WASH
  I
 4th
WASH
  I
 5th
WASH
   2 .0200—
Q x
ug
     -0.00-
         -PREFILTERED
                    UNFILTERED
                                                    SSI98G
                      I
                     1st
                     WASH
          r
         2nd
        WASH
 3rd
WASH
 4th
 WASH
  t
 5th
WASH
                     Figure 122.   (Continued)
                                389
-------
          -0400-
        w
        < .0300-
        UJ

        OL
        Ui
        I- .0200-
        u.
        2
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        UJ
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        UJ
        IT
                                                 SMI308
                                        PREF1LTERED
UNF1LTERED
                          I
                          1st
                        WASH
               I
               2nd
              WASH
 3rd
WASH
 T
 4th
WASH
 5th
WASH
                          Figure 122.  (Continued)
Results of Saved Filter Tests

     All test results are listed  in Tables  218,  219,  220,  and 221.
is presented in Table 222.
                                                 A summary
     The data in Table 222 show  significant  consistency in the mean amount of
oil retained by filters used for IR-Oil  tests  on  flotation effluent.  The
mean amount of oil retained by filters was equivalent to 1.9 to 3.2 mg/1 in
the brine, or equivalent  to 2 to 4  percent of  brine oil content.

     On SS198G, saved filter tests  was run on  filters retained from some
higher oil content brine  samples taken upstream of the gravity separator.
The data are in Table 218.  One  brine sample taken ahead of the gravity
separator had 507 mg/1 of oil, and  the retained filter had 15 mg/1 of oil.
The percentage on the filter was still about 3 percent.

Conclusion of Saved  Filter Tests

     The amount of oil retained  on  filters from the IR-Oil test is much too
small to explain why the  IR-Oil  test results are  sometimes lower than the
                                      390
-------
TABLE 218.  SS198G SAVED FILTER EXPERIMENT

Day
Filters
2
2
2
2
3
3
3
4
4
4
5
5
5
5
5
6
6
6
7
7
7
8
8
9
9
9
10
10
Hour
Saved Dry
1300
1300
1300
1300
0800
0800
1300
0800
0800
1300
0800
0800
1000
1000
1300
0800
0800
1300
0800
0800
1300
0800
0800
0800
0800
1300
0800
0800
Sampl e

9-10 IR
9-10 GR
9-li IR
8— i IR
8— i GR
8— i IR
8— i IR
8— i GR
8— i IR
8— i IR
8— i IR
8—i GR
8— i IR
8— i IR
8— i IR
8— i GR
8--i IR
8— i IR
8—i GR
8— i IR
8—i IR
8—i IR
8—i GR
8—i IR
8—i GR
8—i IR
8—i IR
8—i GR
Oil,
Sample

53
34
118
237
215
313
237
299
507
406
203
170
220
245
186
180
220
224
145
182
199
224
160
207
144
232
220
157
mg/1
Filter

1.8
3.6
4.4
7.7
10.0
10.0
7.8
10.3
15.4
10.2
7.5
7.3
10.0
10.2
9.3
6.3
5.3
5.1
10.5
12.9
5.8
4.7
5.6
5.6
3.9
3.4
4.4
4.4
                     391
-------
                TABLE 219.  SM130B SAVED FILTER EXPERIMENT
Day
Hour
Sample
                                              IR-Qil, mg/1
Sample
Filter
Filters  Saved Dry
1
2
3
4
5
6
7
8
9
10
2
4
5
6
7
Filters
1
2
3
4
5
6
7
8
9
10
1
2
3
4
5
6
7
8
9
10
1300
1300
1300
1300
1300
2000
1300
1300
1300
1300
1300
1300
1300
1300
1300
Saved In Freon
0800
0800
0800
0800
0800
0800
0800 '
1600
0800
0800
1500
0800
0800
0800
0800
0800
0800
0800
0800
0800
                          9—0 IR
                          9—0 IR
                          9-0 IR
                          9—0 IR
                          9—0 IR
                          9—0 IR
                          9—0 IR
                          9-0 IR
                          9—0 IR
                          9—0 IR
                          Blank
                          Blank
                          Blank
                          Blank
                          Blank
                          9—0 IR
                          9—0 IR
                          9—0 IR
                          9—0 IR
                          9—0 IR
                          9—0 IR
                          9—0 IR
                          9—0 IR
                          9—0 IR
                          9—0 IR
                          Blank
                          Blank
                          Blank
                          Blank
                          Blank
                          Blank
                          Blank
                          Blank
                          Blank
                          Blank
                                 64
                                 62
                                 74
                                 39
                                 54
                                 44
                                 35
                                 35
                                 35
                                 27
                                 66
                                 54
                                 86
                                 52
                                 40
                                 33
                                 40
                                 40
                                 36
                                 46
                                 2.2
                                 1.8
                                 2.4
                                 2.0
                                 1.7
                                 1.7
                                 2.2
                                 2.2
                                 1.8
                                 1.1
                                  .2
                                  .1
                                  .1
                                  .1
                                  .1
                                 2.1
                                 3.6
                                 3.2
                                 1.7
                                 1.5
                                 1.5
                                 2.0
                                 2.1
                                 2.7
                                 1.8
                                  .4
                                  .3
                                  .3
                                  .2
                                  .2
                                  .3
                                  .1
                                  .3
                                  .3
                                  .3
                                   392
-------
TABLE 220.  EI18CF SAVED FILTER EXPERIMENT

Day
Filters
1
2
3
4
5
6
7
8
9
10
4
4
10
10
Filters
1
2
3
4
5
6
8
9
10
10
10
Hour
Saved Dry
0800
1300
0800
1300
0800
1300
0800
1300
0800
1300
1500
1500
1300
1300
Saved In Freon
1300
0800
1300
0800
1300
0800
0800
1300
0800
0800
0800
Sample

9—0 IR
9—0 IR
9—0 IR
9-0 IR
9—0 IR
9—0 IR
9—0 IR
9—0 IR
9—0 IR
9—0 IR
Blank
Blank
Blank
Blank

9—0 IR
9—0 IR
9—0 IR
9—0 IR
9—0 IR
9—0 IR
9—0 IR
9—0 IR
9—0 IR
Blank
Blank
IR-Oil,
Sample

59
78
102
116
155
106
50
33
35
35





56
73
110
121
123
110
40
35
38


rtig/1
Filter

2.1
1.2
2.0
2.4
.6
.6
4.4
1.5
1.4
3.2
1.0
.6
.5
.5

6.1
3.2
5.4
1.3
4.3
3.4
1.2
2.4
1.3
.2
.4
                   393
-------
                  TABLE 221.   BDCCF5 SAVED FILTER EXPERIMENT

Day
Filters
1
2
3
4
5
6
7
8
9
10
2
3
7
8
10
Hour
Saved Dry
1300
1300
1300
1300
1300
1300
1300
1300
1300
1300
1300
0800
1300
1300
1300
Sample
9—0 IR
9—0 IR
9--0 IR
9—0 IR
9—0 IR
9—0 IR
9—0 IR
9—0 IR
9—0 IR
9—0 IR
Blank
Blank
Blank
Blank
Blank
IR-Oil,
Samp! e
50
126
139
25
32
40
29
33
32
33





mg/1
Filter
2.3
2.8
6.8
.7
1.0
1.4
1.2
1.4
.8
1.2
0
.1
.2
0
.1

filtered brine IR-Oil test results.  A previously suggested possibility is
that high results may be obtained on some filtered samples because of a water
haze in the Freon when the absorbance is run since the test procedure used did
not call for filtering the Freon extract for filtered brine oil tests.

SPECIAL OIL CONTENT TESTS

     Special oil  content tests were run on two platforms by modifying the
standard acidification procedure.  The Freon extraction was made first with-
out acidifying the brine.  IR-Oil and IR-Oil w/Silica Gel tests were run on
this extract.

     After the first extraction, the same brine sample was acidified in the
regular manner and the Freon extraction was repeated.  Oil content tests were
also run on the second extract.

     The test results are reported in Table 223 and 224 for Platforms BM2C and
SS107.  The general pattern is the same for both platforms, but more pronounced

                                      394
-------
                                  TABLE  222.  SUMMARY OF SAVED FILTER TESTS
CO
UD
cn

Number of
Platform Sample saved filters
Filters Saved Dry
BDCCF5 9—0 IR
SM130B 9—0 IR
EI18CF 9—0 IR
SS198G Various
Filters Saved In Freon
SM130B 9—0 IR
EI18CF 9—0 IR
10
10
10
28
10
9
IR-Oil
comparison of
Mean IR-Oil, mg/1 sample to filter
Sampl e
54
47
77
233
49
78
Filter Blank Filter-blank
2.0 0.1 1.9
1.9 0.1 1.8
1.9 0.6 1.3
7.4
2.2 0.3 1.9
3.2 0.3 2.9
%
4
4
2
3
4
4

     Note:  9—0 IR is the flotation effluent IR-Oil  sample.
-------
           TABLE 223.   BM2C FLOTATION EFFLUENT SPECIAL OIL TESTS
Test condition
Test number
Brine Unacidified
1
2
3
Mean
Brine Acidified
1
2
3
Mean
Unacidified Plus Acidified
1
2
3
Mean
IR-Oil

19
13
14
15

34
34
11
36

53
47
55
52
Oil content,
Dispersed^ '
oil

12
6
8
9

0
0
_£
0

12
6
_8
9
mg/1
SolubleU)
oil

7
7
_6
7

34
34
41
36

41
41
47
43

(1)  As determined by IR-Oil  w/Silica Gel  test.

Note:  All  numbers do not check because of rounding.


for BM2C.  Only BM2C results  are discussed.

     The unacidified extraction results in a relatively low oil content value.
The oil is indicated to be about equal in  dispersed and soluble oil.

     Acidifying the brine results in a substantially higher oil content value.
All of the oil in the second  extraction is indicated to be soluble.

     One theory is that produced brine contains  water soluble salts of
naphthenic and other organic  acids.  The addition of acid to the brine in
conducting the test then forms organic acids which are relatively soluble in
Freon.  These materials are then measured  as oil.  The special  tests reported
here generally confirm this theory.
                                     396
-------
           TABLE 224.  SS107 FLOTATION EFFLUENT SPECIAL OIL TESTS

Test condition
Test number
Brine Unacidified
1
2
3
Mean
Brine Acidified
1
2
3

Acidified Plus Unacidified
1
2
3
Mean
IR-Oil

5
6
_4
5

10
10
_8
9

15
16
11
14
Oil
oil

0
0
_g
0

0
0
_0
0

0
0
_g
0
content, mg/1
(1) (1)
oil

5
6
_4
5

10
10
_8
9

15
16
11
14

(1)   As determined by the IR-Oil w/Silica Gel test.
                                     397
-------
                                 REFERENCES
 1.   Ferraro,  J.  M.  and  S.  M.  Fruh.   "Study  of  Pollution  Control  Technology
     for Offshore Drilling  and Production  Platforms,"   Draft  Report  by  Exxon
     Research  and Engineering  Company for  EPA Industrial  Environmental
     Research  Laboratory,  February  1978.

 2.   Myers,  L.  H.,  B.  L. DePrater,  T.  E. Short, Jr. and B.  B.  Shunatona,  Jr.
     "Offshore Crude Oil Wastewater Characterization Study,"  by  EPA
     Robert  S.  Kerr  Environmental Research Laboratory,  August 1974.

 3.   Cross,  E.  F.,  E.  C. Sebesta  and W. T.  Winn, Jr.   "Determination of  Best
     Practicable  Control Technology Currently Available to  Remove Oil From
     Water Produced  With Oil and  Gas,"  prepared by Brown  &  Root,  Inc. for the
     Sheen Technical Subcommittee of the Offshore Operators Committee,
     March 1974.

 4.   Wyer, R.  H., H. D.  Van Cleave   and K. E. Biglane.  "Evaluation  of  Waste-
     water Treatment Technology for Offshore Oil Production Facilities,"
     Proceedings  of  Seventh Annual  Offshore  Technology  Conference, OTC  2232,
     May 5-3,  1975.

 5.   Tiratsoo,  E. N.   "Oilfields  of the World," Scientific  Press  Limited,
     Beaconsfield,  England, 1973.   pp.  268.

 6.   Halbouty,  M. T.   "Salt Domes Gulf Region,  United States  and  Mexico,"
     Gulf Publishing Company,  Houston,  Texas, 1967. pp. 87.

 7.   APHA, AWWA,  and WPCF.   Standard Methods for the Examination  of  Water and
     Wastewater.   "Method  502E."  APHA, Washington, D.C., 14th Edition, 1976.
     pp. 520-521.

 8.   Gruenfeld, M.  and U.  Frank.  "A Review  of  Some Commonly  Used Parameters
     for the Determination  of  Oil Pollution," Proceedings of  1977 Oil Spill
     Conference,  New Orleans,  Louisiana, March  8-10, 1977.  pp.  487-491.

 9.   Matovitch, M.  A.  "The Existence and  Effects of Water  Soluble Organic
     Components in Produced Brine," December 1976. Shell  Oil  Company Report
     submitted to Regional  Administrator,  EPA Region VI,  May  26,  1978.

10.   Miller, J. W.  and C.  I. Yaws.   "Surface Tension of Liquids," Chemical
     Engineering, October  25,  1976.   pp. 127-129.
                                     398
-------
                                 APPENDIX A
                           ANALYTICAL PROCEDURES

OIL AND GREASE INFRARED (OFFSHORE)
1.0   References
      1.1  Environmental Protection Agency, 1979, "Methods for Chemical
           Analysis of Water and Wastes," Environmental Monitoring and Support
           Laboratory, Environmental  Research Center, Cincinnati, Ohio  45268,
           pages 413.2-1 through 413.2-3.
      1.2  Operational Instructions,  Model OCMA-200 Oil Content Analyzer,
           Horiba Instruments Incorporated, Houston, Texas  77092
           Note:  The technique detailed in this section follows the EPA
                  Storet No. 00560 test exactly as given in reference 1.1
                  for extraction (sample size, extract volume and the number
                  of extraction steps) only.  Following step 7.6 (ref. 1.1)
                  of Storet No. 00560, quantification in the field will employ
                  Horiba OCMA-200 spectrometers (ref. 1.2).
2.0   Equipment and Reagents
      2.1  Separatory funnel, 2000 ml, with Teflon stopcock.
      2.2  Oil-in-water analyzer, Horiba OCMA-200.
      2.3  Graduated cylinder, stoppered, 100 ml.
      2.4  Syringes, glass, 10 ul.
      2.5  Wash bottle, glass, 500 ml.
      2.6  Freon TF (1,1,2 - trichloro - 1,2,2 - trifluoroethane).
      2.7  Crude oil
      2.8  Volumetric flask, 100 ml,  50 ml.
      2.9  Hydrochloric acid, 6 N.
      2.10 Pipet, 1 ml, 10 ml.
                                      399
-------
      2.11 Dispenser, glass, 50 ml.
      2.12 Bottle, glass, 125 ml.
      2.13 Bottle, glass, 1 liter.
      2.14 Filter paper, Whatman No.  40, 11 cm.
      2.15 Glass funnel
3.0   Calibration
      3.1  Inject 10 ml  of Freon TF into extraction chamber.
      3.2  Turn extractor control to  the open position.
      3.3  Adjust zero control.
      3.4  Prepare 100 ppm standard by injecting 10 micro!iters of oil into
           a 100 ml  volumetric flask  and dilute with Freon.
      3.5  Inject 10 ml  of 100 ppm standard into extraction  chamber.
      3.6  Open extraction cell and discharge sample.
      3.7  Close extraction cell and  refill with 10 ml  of standard.
      3.8  Adjust span for 100 ppm oil.
4.0   Field Procedure
      4.1  Purge sample port.
      4.2  Fill the bottle exactly to the 1.0 liter mark.
      4.3  Add 5 ml  hydrochloric acid to the sample bottle.   After mixing the
           sample, check the pH by touching pH-sensitive paper to the cap to
           insure that the pH is 2 or lower.  Add more acid, if necessary.
      4.4  Rinse a clean 2000 ml separatory funnel  with three successive 10
           ml portions of Freon TF and drain.  Discard rinsings after check-
           ing for contamination.
      4.5  Pour the water sample into the separatory funnel.
      4.6  Add 30 ml Freon to the sample bottle and rotate the bottle to rinse
           the sides.  Transfer the solvent into the separatory funnel.
           Extract by shaking vigorously for 2 minutes.  Allow the layers to
           separate.
      4.7  Filter the solvent layer into a 100 ml volumetric flask through a
           funnel containing a solvent-moistened filter paper.
                                      400
-------
      Nota 1:   An emulsion that fails to dissipate can be broken by pouring
               about 1 g sodium sulfate into the filter paper cone and
               draining the emulsion through the salt.  Additional 1 g por-
               tions can be added to the cone as required.
      4.8  Repeat (4.6 and 4.7) twice more with 30 ml  portions of fresh
           solvent, combining all solvent in the volumetric flask.
      4.9  Rinse the tip of the separatory funnel, filter paper, and the
           funnel with a total  of 10-20 ml Freon and collect the rinsings in
           the flask.  Dilute the extract to 100 ml, and stopper the flask.
      4.10 Collect this extract in a 125 ml  glass bottle, label  and use for
           subsequent analysis onboard as well  as ashore.
      4.11 Dilute 10 ml of this extract to 100 ml using Freon TF.
      4.12 Inject 10.0 ml  of this Freon extract into analyzer.
      4.13 Open extractor and discharge controls and discard effluent.
      4.14 Refill analyzer with a fresh 10.0 ml aliquot of extract, open
           extractor and measure oil concentration.
      4.15 Discharge sample and repeat step  4.14.  Successive readings of
           each sample should agree within 5 ppm.
      4.16 Retain remaining Freon extract for additional analysis in
           appropriately labeled glass bottle and seal.
      4.17 If reading goes off scale (100 ppm), pipet 10.0 ml of extract into
           a 50 ml volumetric flask and dilute with Freon TF.
      4.18 Determine oil concentration in diluted Freon extract  as outlined
           in steps 4.12 - 4.15.
5.0   Laboratory Procedure
      5.1  Not applicable.
6.0   Calculation
      6.1  The oil-in-water concentration with the first dilution only will
           be equal to the instrument reading if all volumes are taken as
           specified.
      6.2  Oil-in-water concentration with any subsequent dilution:
           ppm oil = ppm instrument x D
           Where:        Q - total  volume of dilution  (ml)
                             volume of Freon extract diluted (ml)
                                     401
-------
      6.3  Record data in laboratory notebook.  At end of each day transfer
           data from notebook to data sheets, referring data sheet back to
           actual notebook number and page under the "page	of	"
           section of the data sheet.
      6.4  For final data report, convert oil measurement from ppm to mg/1
           by the formula:
                oil (mg/1) = oil (ppm) x F
                Where F = Correction factor, specific gravity of platform
                          specific oil used for Horiba calibration, at 25°C.
7.0   Quality Control
      7.1  Calibration must be performed at least once a day.
      7.2  Successive readings of each sample should agree within 5 ppm.  The
           average of the last two readings will be reported.
      7.3  Repeat calibration procedure if a different container of Freon TF
           is used.
OIL AND GREASE GRAVIMETRIC (OFFSHORE AND ONSHORE)
1.0   References
      1.1  Environmental  Protection Agency, 1979, "Methods for Chemical
           Analysis of Water and Wastes," Environmental Monitoring and
           Support Laboratory, Environmental Research Center, Cincinnati,
           Ohio 45268.
           Note:  The technique detailed in this section follows the EPA
                  procedures as listed in reference 1.1 exactly as written.
2.0   Equipment and Reagents
      2.1  Separatory funnel, 2000 ml.
      2.2  Vacuum pump.
      2.3  Flask, distilling, 125 ml.
      2.4  Filter paper,  Whatman No. 40, 11 cm.
      2.5  Funnel, glass.
      2.6  Hydrochloric acid, 6 N.
      2.7  Freon TF (1,1,1 - trichloro - 1,2,2 - trifluoroethane).
      2.8  Sodium sulfate, anhydrous crystal.
                                      402
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      2.9  Bottle, glass, 1000 ml, 125 ml.
      2.10 Syringe, glass, 10 ml.
      2.11 Water bath, variable temperature.
3.0   Calibration
      3.1  Not applicable.
4.0   Field Procedure
      4.1  Purge sample port.
      4.2  Fill a 1 liter bottle to the 1.0 liter volume mark.
      4.3  Add 5 ml 6N hydrochloric acid.
      4.4  Pour the sample into a separatory funnel.
      4.5  Add 30 ml Freon TF to the sample bottle and rotate the bottle to
           rinse the sides.
      4.6  Transfer the solvent to the separatory funnel, stopper and shake
           vigorously for 2 minutes.
      4.7  Filter the solvent layer into a 125 ml bottle through a funnel
           containing solvent-moistened filter paper.  An emulsion present in
           the extract may be broken by adding a gram of sodium sulfate into
           the filter paper cone.
      4.8  Repeat steps 4.4 - 4.7 twice more, with additional portions of
           fresh solvent, combining all extracts in a glass bottle.
      4.9  Rinse the tip of the separatory funnel, filter paper and  funnel
           with 10-20 ml Freon and collect the rinsings in the 125 ml bottle.
           Seal, label and place in storage container for shipment ashore.
5.0   Laboratory Procedure
      5.1  Extract 3 1-liter deionized water samples, steps 4.1 - 4.8,
           using Freon TF from the same batch which was used in the  field.
      5.2  Transfer the Freon extract to a tared distilling flask.
      5.3  Rinse the glass bottle with 10 ml Freon and add washings  to the
           flask.
      5.4  Evaporate the solvent in a water bath at 70°C.  Dry by placing
           the flask on a covered 80°C water bath for exactly 15 minutes.
      5.5  Draw N£ through the flask by means of an applied vacuum for 1
                                     403
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           minute.  Watch the neck of the flask for neck ring condensation
           which would trap solvent and produce a heavy weighing.

      5.6  Cool  in desiccator for 30 minutes and weigh.

6.0   Calculations

      6.1  Oil  in water concentration using gravimetric procedure:
                             n 0
           ppm (mg/1) oil =   y


           Where:  R = residue, gross weight of flask minus tare weight
                       (milligrams)

                   B = blank, residue of equivalent volume of solvent
                       (milligrams)

                   V = Sample volume (liters)

      6.2  Record data in laboratory notebook.   At end of each day transfer
           data  from notebook to data sheets, referring data sheet back to
           actual notebook number and page under the "page	of	"
           section on the data sheet.

7.0   Quality Control

      7.1  A minimum of 3 blanks will be run per set of samples from one
           platform.

      7.2  When  a new container of Freon TF is  used in the field, a new set
           of blanks is required.

      7.3  The analytical balance must have been calibrated and verified
           accurate to within 0.1 mg.

PARTICLE SIZE DISTRIBUTION (OFFSHORE)

      Equipment, personnel, technique, as well  as data reduction, to be
provided by Rockwell International.

      Note:  Each time a particle size distribution test is run an IR-Oil
             test, an IR-Oil  with silica gel test, and a filtered brine
             test will be run.  The procedures  for these tests appear
             elsewhere in this document.

TEMPERATURE MEASUREMENT (OFFSHORE)

1.0   Reference

      1.1  American Society for Testing and Materials, "1974 Annual Book of
           ASTM  Standards, Part 24, Petroleum Products and Lubricants,"


                                    404
-------
           American Society for Testing and Materials, 1916 Race St.,
           Philadelphia, PA 19103.
2.0   Equipment
      2.1  Thermometer, dial  type, 0-100°C.
      2.2  Thermometer, mercury, 0-100°C.
      2.3  Bottle or suitable container for sample collection.
3.0   Calibration
      3.1  At a minimum frequency of once a day, place both the dial  type and
           mercury thermometers in a bottle full of sample water.
      3.2  Allow 1 minute for the thermometers to equilibrate.
      3.3  Compare and note any differences in the temperature  readings
           using the mercury thermometer as the standard.
4.0   Field Procedure
      4.1  Allow about 5 liters of effluent to flow out of the  system at
           some convenient rate.
      4.2  Collect about 1 liter in a bottle and immediately insert the dial
           thermometer.
      4.3  Wait 1 minute until  the thermometer has equilibrated and read the
           temperature.
      4.4  If the sample site has a temperature well, place the thermometer
           directly into the port, wait 1 minute and read  the temperature.
5.0   Laboratory Procedure
      5.1  Not applicable.
6.0   Calculations
      6.1  Record data in laboratory notebook.  At end of  each  day transfer
           data from notebook to data sheets,  referring data sheet back to
           actual notebook number and page under the "page 	 of 	"
           section on the data  sheet.
7.0   Quality Control
      7.1  All dial thermometer readings will  be corrected based upon
           deviations from a mercury thermometer meeting National  Bureau of
           Standards specifications.
                                     405
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pH (OFFSHORE)
1.0   Reference
      1.1  American Society for Testing and Materials,  "1978 Annual  Book of
           ASTM Standards,  Part 31,  Water," American  Society for Testing and
           Materials,  1916  Race St., Philadelphia,  PA 19103.
           Note:   The  technique detailed in this  section  follows "Method B -
                  Routine or Continuous Measurements  pH"  (Reference  1.1).
                  A combination electrode (Corning  No.  476051)  will  be used,
                  which is  Sodium-compensated in  the  pH range 1-10.   If
                  higher pH (10) is  encountered,  a  high alkaline combination
                  electrode (IL No.  14063)  will be  used.
2.0   Equipment and Reagents
      2.1  pH  meter, battery operated.
      2.2  Electrode,  combination.
      2.3  Standard buffers, pH 4.00, 6.86, 9.18  at 25°C.
      2.4  Deionized water.
      2.5  Kim-Wipes or equivalent.
      2.6  Bottle or other  suitable  container for sample  collection.
3.0   Calibration
      3.1  Calibrate the instrument  immediately prior to  each use.
      3.2  Immerse the combination electrode (Corning 476051) into pH 7.00
           buffer.
      3.3  Adjust temperature knob to the previously  determined temperature
           of  the sample.
      3.4  Adjust the  calibrate knob to pH  7.00 reading.
      3.5  Remove electrode, rinse with deionized water and  wipe clean.
4.0   Field Procedure
      4.1  This measurement is made  in  conjunction  with the  temperature
           determination.
      4.2  Allow about 5 liters of effluent to flow out of the system at
           some convenient  rate.
      4.3  Collect about 1  liter of  sample  and proceed with  the temperature
                                     406
-------
           measurement, if required.
      4.4  Immerse combination electrode in sample and agitate gently for 30
           seconds.
      4.5  Read pH after steady state has been achieved.
      4.6  Remove electrode, rinse with deionized or clean tap water and
           wipe clean.
      4.7  If the pH is 10, change to the high alkaline electrode (IL-14063),
           calibrate using the pH 9.18 buffer and repeat steps 4.3-4.5.
5.0   Laboratory Procedure
      5.1  Not applicable.
6.0   Calculations
      6.1  Record data  in laboratory  notebook.  At end of each day transfer
           data from notebook to data sheets, referring data sheet back  to
           actual notebook number and page under the "page	of	"
           section on the data sheet.
7.0   Quality Control
      7.1  Instrument will be calibrated prior to each use.
      7.2  Perform a response verification of electrode every other day
           using all three buffers.  Verify Nernst response of the combi-
           nation electrode using the slope equation given in the follow-
           ing table.  Results should be within 95-99% agreement, or the
           electrode is to be replaced.
                                     407
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CONSTANTS FOR CALCULATION OF RESPONSE EQUATION SLOPE
                   F/(.2.3026 RT)A
       Temperature               F/(2.302* RT)
           °C                          V1
            0                       18.4512
            5                       18.1195
           10                       17.7996
           15                       17.4907
           20                       17.1924
           25                       16.9041
           30                       16.6253
           35                       16.3555
           40                       16.0944
           45                       15.8414
           50                       15.5963
           55                       15.3587
           60                       15.1282
           65                       14.9045
           70                       14.6873
           75                       14.4764
           80                       14.2714
           85                       14.0722
           90           •            13.8784
           95                       13.6899
A.  The above data were calculated using a precise value of
    the logarithmic conversion factor (2.302585) and values
    of the fundamental constants.

                    F = 96 487.0C/eq
                    R = 8.31433 J/K mol
                    T = 273.15 + °C
                         408
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BOILING RANGE DISTRIBUTION (ONSHORE)

1.0   Reference

      1.1  American Society for Testing and Materials "1974 Annual Book of
           ASTM Standards Part 24, Petroleum Products and Lubricants,"
           American Society for Testing and Materials, 1916 Race St.,
           Philadelphia, PA 19103.

           Note:  The technique detailed in this section follows ANSI/
                  ASTM D22887-73 Standard Test Method for Boiling Range
                  Distribution of Petroleum Fractions by Gas Chromato-
                  graphy exactly as given in reference 1.1.

2.0   Equipment and Reagents

      2.1  Perkin-Elmer, Sigma 2 Gas Chromatograph equipped with a flame
           ionization detector.

      2.2  Perkin-Elmer, Sigma 10 Chromatography Data Section.

      2.3  Calibration mixture of a homologous series of n-alkanes from C-12
           through C-32, plus o-xylene, n-butylbenzene, tri-isopropylbenzene,
           n-decylbenzene and tetrodecylbenzene.

      2.4  Syringe, 10 ul.

      2.5  Miscellaneous laboratory glassware.

3.0   Calibration

      3.1  A mixture of hydrocarbons of known boiling points covering the
           boiling range of the sample shall be prepared according to
           reference 1.1.

      3.2  At least one compound in the mixture must have a boiling point
           lower than the initial boiling point of the sample.

      3.3  If the sample contains significant quantities of n-paraffins which
           can be identified on the chromatogram, these peaks will be used
           as internal boiling point calibrations.

      3.4  Run this calibration mixture in exactly the same manner as the
           crude oil sample is to be done.  Record the retention time of
           each component.  Plot retention times vs. atmospheric boiling
           points to obtain the calibration curve.  From this curve,  assign
           boiling temperatures to each of the intervals at which area
           measurements are made.

      3.5  The calibration curve must be verified each time the determination
           is made.
                                     409
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4.0   Field Procedure

      4.1  Collect a sample of crude oil  for boiling range determination from
           the platform crude oil  storage tank in duplicate, clean 125 ml
           glass bottles equipped with Teflon-lined screw caps, label and
           store in shipping containers for subsequent shipment ashore.
           Duplicate samples are to be collected to provide a backup sample
           in case of possible breakage.

5.0   Laboratory Procedure

      5.1  Run the chromatograph through  the temperature programming sequence
           to verify accurate instrument  settings.

      5.2  Run the calibration mixture through the gas chromatograph analysis
           to verify stable operating conditions and accurate data recording.

      5.3  Run the crude oil sample from  one of the two samples for each
           platform through the gas chromatograph analysis.

      5.4  Record the peaks at a sensitivity setting that allows the maximum
           peak height compatible with data station recording capabilities.

      5.5  The data station will output time, integrated area for each peak,
           total cumulative area,  and amount at time intervals considerably
           less than 1% of the total retention time equivalent to 583°C.
           Time and cumulative area at 0.5 and 99.5% of total area will be
           obtained from these data.

6.0   Calculations

      6.1  Record the time and cumulative area count at 0.5% of the total
           area.  Mark this point as the  intiial boiling point of the sample
           (IBP).

      6.2  Record the time and cumulative area count at 99.5% of the total
           area.  Mark this point as the  final boiling point of the sample
           (FBP).

      6.3  Divide the cumulative area at  each interval between IBP and FBP by
           the total cumulative area counts.  This will give the percent of
           sample recovered at each interval.

      6.4  Tabulate the percent recovered at each interval and the boiling
           temperature assigned to that interval from the calibration
           procedure 3.0.

7.0   Quality Control

      7.1  The gas chromatograph detector used must have sufficient sensi-
           tivity to detect 1.0 percent dodecane with a peak height of at
           least 10% of full scale on the recorder.

                                     410
-------
      7.2  When operating at this sensitivity level,  detector stability must
           be such that a baseline drift of not more  that 1% per hour is
           obtained.

      7.3  The detector must be capable of continuous operation at a tem-
           perature equivalent to the maximum column  temperature employed,
           and it must be connected to the column without inducing cold
           spots.

      7.4  The gas chromatograph must be capable of program temperature
           operation  over a range sufficient to establish a retention time of
           at least 1 minute for the IBP and to elute the entire sample.

      7.5  The programming rate must be sufficiently  reproducible to obtain
           retention  time repeatability of 0.1 minute (6 seconds) for each
           component  in the calibration mixture.

      7.6  The sample inlet system must be capable of operating continuously
           at a temperature equivalent to the maximum column temperature
           employed,  and be connected to the column without cold spots.

      7.7  A recorder must be used to obtain a trace  of the compounds eluting
           off the column with a full-scale response  time of 2 seconds or
           less.

      7.8  Data must  be collected by electronic integration.  A timing device
           is to be used to cause the integrator to print out at equal time
           intervals.

      7.9  Gas chromatographs must be equipped with constant flow controllers
           capable of holding carrier gas flow constant to 1% over the full
           operation  temperature range.

      7.10 Resolution calculated from the distance between C-16 and C-18
           n-paraffin peaks must be at least 3 and not more than 8 when
           calculated in the normal manner.

SPECIFIC GRAVITY, OIL AND WATER (OFFSHORE)

1.0   Reference

      1.1  American Society for Testing and Materials, "1974 Annual  Book of
           ASTM Standards, Part 23, Petroleum Products and Lubricants,"
           American Society for Testing and Materials, 1916 Race St.,
           Philadelphia, PA 19103.

           Note:  The technique detailed in this section follows the.
                  procedures of ASTM D 1298-67 (1972) as listed in reference
                  1.1 exactly as written.

2.0   Equipment


                                     411
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      2.1  Hydrometers,  ASTM 82H-88H,  111H,  112H.

      2.2  Hydrometer cylinder.

      2.3  Thermometer,  mercury,  0-100°C.

3.0   Calibration

      3.1  Specific gravity measurements in  an opaque liquid require a
           correction factor since hydrometers are calibrated to read at
           the principal  surface  of the liquid.

      3.2  For a particular hydrometer, record the maximum height above the
           principal  surface of  the liquid to which the liquid rises on the
           hydrometer scale when  the hydrometer is immersed in a transparent
           oil having a  surface  tension similar to that of the sample.

4.0   Field Procedure

      4.1  Purge sample  port.

      4.2  Fill hydrometer cylinder from sample port without splashing, to
           avoid the formation of air  bubbles.

      4.3  Insert a thermometer  into the sample; wait until  the sample reaches
           equilibrium.   Record  the temperature after gently stirring the
           sample with the thermometer.

      4.4  Lower the hydrometer  into the sample.  Take care to avoid wetting
           the stem above the level to which it will  be immersed in the
           liquid.

      4.5  Depress the hydrometer about two  scale  divisions into the liquid,
           and with a slight spin, release it.

      4.6  When the hydrometer has come to rest, floating freely away from
           the walls of  the cylinder,  estimate the scale reading to the
           nearest 0.0001 sp gr.

      4.7  With an opaque liquid  take  a reading by observing, with the eye
           slightly above the plane of the surface of the liquid, the point
           on the hydrometer scale to  which  the sample rises.  Correct this
           reading based upon the meniscus calibration for the particular
           hydrometer being used.

      4.8  Immediately after observing the hydrometer scale value, stir the
           sample with the thermometer and record  the temperature.  Should
           this temperature differ from the  previous reading by more than
           0.5°C, repeat the hydrometer and  thermometer readings until the
           temperature becomes stable with 0.5°C.
                                     412
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5.0   Laboratory Procedure
      5.1  Not applicable.
6.0   Calculations
      6.1  Report specific gravity, with meniscus calibration where necessary,
           Report temperature of sample at time specific gravity was measured,
      6.2  Record data in laboratory notebook.  At end of each day transfer
           data from notebook to data sheets, referring data sheet back to
           actual notebook number and page under the "page	of	"
           section on the data sheet.
7.0   Quality Control
      7.1  Sample must reach thermal equilibrium, less than 0.5°C variation
           in two successive readings, before an accurate specific gravity
           measurement can be made.
      7.2  Record the temperature at which the specific gravity determina-
           tions were made.
WATER CUT (OFFSHORE)
1.0   Reference
      1.1  American Society for Testing and Materials, "1974 Annual Book of
           ASTM Standards, Part 24, Petroleum Products and Lubricants,"
           American Society for Testing and Materials, 1916 Race St.,
           Philadelphia, PA 19103.
           Note:  The technique detailed in this section follows the proce-
                  dures of ASTM D 1796-68 (1973) as listed in reference 1.1
                  without modification.
2.0   Equipment and Reagents
      2.1  Centrifuge, hand powered.
      2.2  Centrifuge tube, API, 12.50 ml.
      2.3  Toluene (water-saturated).
      2.4  Nalco 103 (or Visco 103) demulsifier.
3.0   Calibration
      3.1  Not required.
4.0   Field Procedure
                                     413
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      4.1  It is recommended that the centrifuge tube be filled directly
           from the circulating stream.   If this is not possible, transfer
           the sample in a bottle and shake thoroughly immediately before
           filling the centrifuge tube.   Purge sample port prior to filling
           tube.

      4.2  Fill  each of two centrifuge tubes to the 50% mark with sample to
           be tested.

      4.3  Add solvent to the 100% mark  and 1 drop of demulsifier.

      4.4  Stopper the tubes and shake until the contents are thoroughly
           mixed.

      4.5  Place tubes in the centrifuge and revolve for 3 to 10 minutes,
           depending upon the separation character of the mixed phases.

      4.6  Remove the tubes and record the combined volume of water and
           sediment in each tube to the  nearest 0.1%.

      4.7  Replace the tubes in the centrifuge and revolve again 3 to 10
           minutes.

      4.8  Again record the combined water and sediment.  If there is a
           difference of more than 0.2%  between the first and second
           readings, continue centrifuging until two consecutive readings
           check within 0.2%.

      4.9  The sum of the final readings on the two 12.50 ml centrifuge tubes
           represents the volume percentage of water and sediment in the
           sample.

5.0   Laboratory Procedure

      5.1  Not applicable.

6.0   Calculations

      6.1  Record data in laboratory notebook.  At end of each day transfer
           data from notebook to data sheets, referring data sheet back to
           actual  notebook number and page under the "page	of	"
           section on the data sheet.

7.0   Quality Control

      7.1  Repeat centrifuging samples until consecutive readings agree
           within 0.2%.

SUSPENDED SOLIDS (OFFSHORE AND ONSHORE)

1.0   References
                                      414
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      1.1  Environmental  Protection  Agency,  1979,  "Methods  for Chemical
           Analysis of Water and Wastes,"  Environmental  Monitoring  and
           Support Laboratory,  Environmental  Research Center,  Cincinnati,
           Ohio 45268.
      1.2  American Society for Testing and  Materials, "1978 Annual  Book of
           ASTM Standards,  Part 31,  Water,"  American Society for Testing and
           Materials,  1916  Race St., Philadelphia,  PA 19103.
           Note:  The  techniques detailed  in  this  section follow the
                  procedures given in reference 1.1 for  total  non-filtereable
                  residue (Storet No. 00530).   Quality control  procedures
                  are  taken from the Standard  Test  Method D 1888-67 (1974)
                  Particulate and Dissolved  Matter  in Water, as given  in
                  reference 1.2.
2.0   Equipment
      2.1  Filter holder, inline 47  mm.
      2.2  Filters, glass fiber, 47  mm, preashed,  preweighed and packaged  in
           individual  petri dishes.
      2.3  Graduated cylinder,  1 liter.
      2.4  Vacuum pump, hand operated.
      2.5  Filter flask,  1  liter.
      2.6  Hydrochloric acid 6N.
      2.7  Freon TF (1,1,2  - trichloro - 1,2,2 - trifluoroethane).
      2.8  Balance, analytical, 0.1  mg.
      2.9  Dei onized water.
      2.10 Forceps.
3.0   Calibration
      3.1  Not applicable.
4.0   Field Procedure
      4.1  Rinse empty filter holder with  deionized water.
      4.2  Insert preweighed filter  into holder using forceps.
      4.3  Purge sample port.
      4.4  Attach inlet side of loaded filter  holder to  sampling port.
                                     415
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      4.5  Turn on flow and collect filtered effluent into the 1 liter
           filter flask applying a suction with the hand vacuum pump.
      4.6  Continue filtration until  flow rate has decreased sufficiently to
           indicate the filter is beginning to clog.
      4.7  Disconnect the filter holder and reconnect it to a glass  funnel.
      4.8  Filter 50 ml of prefiltered (0.45 micron)  deionized water through
           the filter holder to wash  the glass fiber  filter.
      4.9  Disconnect the filter holder, remove filter and replace it  in  the
           petri dish, inventory and  refrigerate prior to shipment.
      4.10 Record the volume of water filtered, and number of filter.
      4.11 Store filter holder in cleaning solution.
5.0   Laboratory Procedure
      5.1  Place glass fiber filter in vacuum desiccator and dry to  constant
           weight.
      5.2  Weight filter to the nearest milligram and record as total  suspend-
           ed solids, gross weight.
      5.3  Wash filter with 100 ml  Freon TF and vacuum dry.
      5.4  Weigh filter and record as organic soluble suspended solids,  gross
           weight.
      5.5  Wash filter with 100 ml  6N HC1  and again vacuum dry.
      5.6  Weigh filter and record as acid soluble suspended solids, gross
           weight.
6.0   Calculations
      6.1  Total Suspended Solids
           TSS (mg/1) = [R - (T - B)] x 1000
                                 V
           Where:   R = residue + filter (grams)
                    T = tare weight of filter (grams)
                    B = blank filter  weight loss after drying (grams)
                    V = volume filtered (liters)
                                     416
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      6.2  Freon Soluble Suspended Solids
           T  . (R - R0 - B0)  x 1000
           °"	v
           Where:  R0 = residue + filter after solvent wash (grams)
                   BQ = blank filter weight loss after solvent wash  (grams)
      6.3  Freon Insoluble Residue
           TI = TSS - To
      6.4  Acid Soluble Suspended Solids
                (RQ - Ra - Ba) x 1000
           Ta =           v
           Where:  Ra = residue + filter acid wash (grams)
                   Ba = blank filter weight loss after acid wash (grams)
      6.5  Fixed Suspended Solids
           FSS = TSS - TQ - Ta
      6.6  Record data in laboratory notebook.  At end of each day transfer
           data from notebook to data sheets, referring data sheet back  to
           actual notebook number and page under the "page	of	"
           section on the data sheet.
      6.7  The test results for suspended solids will  be reported as  follows
           in mg/1:  Total, Freon Soluble, Freon Insoluble, Fixed, and Acid
           Soluble.
      6.8  Process one blank filter through steps 5.1  - 5.8 for every 10
           samples.
SURFACE TENSION, OIL AND WATER (OFFSHORE)
1.0   Reference
      1.1  American Society for Testing and Materials, "1978 Annual  Book
           of ASTM Standards, Part 31, Water," American Society for  Testing
           and Materials, 1916 Race St., Philadelphia, PA 19103.
           Note:  The test method detailed in this section  follows procedures
                  for the Standard Test Method D 1590-60 (1977)  for Surface
                  Tension of Water exactly as cited in reference 1.1.
                                     417
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2.0   Equipment and Reagents
      2.1  Tens IOmeter, Du Nouy ring.
      2.2  Vibration-free support.
      2.3  Weights, analytical.
      2.4  Propane torch.
      2.5  Evaporating dish, 100 ml.
      2.6  Chromic - sulfuric acid  cleaning solution.
      2.7  Methyl ethyl ketone
      2.8  Hydrochloric acid, 2N.
3.0   Calibration
      3.1  Level  the tensiometer and  adjust the length of the torsion arm by
           means  of weights and the adjustments so that each unit of the
           graduated scale represents a pull  on the ring of 1 dyne/cm.
      3.2  From the calibration weight and instrument reading, calculate the
           grams  of pull on the ring  represented by each scale division.
           Use this value for calculating the conversion factor, F, which is
           employed to give corrected surface tension values.
4.0   Field Procedure
      4.1  Collect the sample using only thoroughly cleaned glass-stoppered
           vessels (Note 1).  Purge sample ports prior to collection.
      4.2  After the tensiometer has  been calibrated, check the level and
           insert the freshly cleaned platinum ring (Note 2).
      4.3  Level  the plane of the ring and set the measuring dial at zero.
      4.4  Adjust the ring to the zero position.
      4.5  Place the sample to be tested in the thoroughly cleaned
           evaporating dish (Note 1)  on the sample platform.
      4.6  Raise the sample platform by means of the adjusting screw until
           the ring is completely submerged,  but not to exceed 3 mm.
      4.7  Permit the sample surface to age for 30 seconds.
      4.8  Lower the platform slowly by means of the adjusting screw, at the
           same time increasing the torque of the ring system by means of
           the dial adjustment.  These two simultaneous adjustments must be
                                     413
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           carefully made so that the ring system remains constantly in the
           zero position.

      4.9  Record the dial  reading when the ring breaks free of the sample
           film.  Complete the break within 60 seconds after starting
           measurement.

      4.10 Measure and report temperature of test samples immediately after
           readings are taken.

      4.11 Samples showing evidence of free oil  will  be settled for 30
           minutes under susceptibility to separation test conditions.  The
           surface tension test will be run on the settled brine.

      4.12 Extra samples will be taken when oil  content is high (400 mg/1)
           when a regular sample is not scheduled.

           Note 1:  The recommended cleaning procedure comprises a 1-hour
                    soak in chromic-sulfuric acid, five deionized water
                    rinses and overnight storage in deionized water.  Glass-
                    ware used for this test should be kept segregated and
                    stored in deionized water.

           Note 2:  For each sample, the platinum ring must be freshly clean-
                    ed by immersing in nethyl  ethyl  ketone, permitted to dry,
                    immersing in hydrochloric acid (2N) and rinsing
                    thoroughly with deionized water.   The ring is again
                    immersed in methyl ethyl ketone,  permitted t9 dry and then
                    heated to a white heat in the oxidizing portion of a gas
                    flame.   Successive measurements on the same sample will
                    require cleaning and flaming the  ring for each determina-
                    tion.

5.0   Laboratory Procedure

      5.1  Not applicable.

6.0   Calculation

      6.1  Calculate the corrected surface tension as follows:  Surface
           tension, dynes/cm = PF

           Where:  P = scale reading in dynes/cm when film breaks

                   F = correction factor

      6.2  The values of F are based upon two calculated values, R3 (D-d)/M
           and R/r.  These parameters are used with a standard table to
           obtain the correction factor F.

           Where:  R = mean radius of the ring (cm)


                                    419
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                   r = radius of the wire in the ring (cm)
                   D = density of liquid
                   d = density of air saturated with vapor of liquid
                   M = weight of liquid raised above free surface of the
                       liquid (equivalent to dial  reading multiplied by
                       factor derived in 3.2).
      6.3  Record data in laboratory notebook.  At end of each day transfer
           data from notebook to data sheets, referring data sheet back to
           actual notebook number and page under the "page	of	"
           section on the data sheet.
7.0   Quality Control
      7.1  Make at least two measurements each on  separate sample portions,
           making additional measurements in accordance with the magnitude of
           the overall variation of the first two.
      7.2  The precision of this method is 0.3 dyne/cm.
      7.3  Record calibration of each tensiometer  in the calibration log.
SILICA GEL ADSORPTION (OFFSHORE)
1.0   Reference
           Standard Methods for the Examination of Water and Wastewater.
           14th Edition, 1975.  American Public Health Association,
           American Water Works Association, Water Pollution Control
           Federation.  American Public Health Association, 1015 Eighteenth
           Street NW, Washington, DC 20036.
           Note:  The techniques detailed in this  section follow Standard
                  Method, 502 E., Hydrocarbons, exactly as given in reference
                  1.1.
2.0   Equipment and Reagents
      2.1  Oil-in-water analyzer, Horiba OCMA-200.
      2.2  Syringe, glass 10 yl, 10 ml.
      2.3  Freon TF  (1,1,2 - trichloro - 1,2,2 - trifluoroethane).
      2.4  Silica gel, 100 - 200 mesh, deactivated with 2% water.
      2.5  Magnetic stirrer with Teflon stirring bar.
      2.6  Volumetric flask, 100 ml.
                                     420
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      2.7  Bottles, glass, 125 ml.
3.0   Calibration
      3.1  Inject 10 ml  of Freon TF into extraction chamber.
      3.2  Turn extractor control to the open position.
      3.3  Adjust zero control.
      3.4  Prepare 100 ppm standard by injecting 10 micro!iters of oil into a
           100 ml volumetric flask) and dilute with Freon.
      3.5  Inject 10 ml  of 100 ppm standard into extraction chamber.
      3.6  Open extraction cell and discharge sample.
      3.7  Close extraction cell and refill with 10 ml  of standard.
      3.8  Adjust span for 100 ppm oil.
4.0   Field Procedure
      4.1  The diluted extract analyzed for IR determination in produced
           water is to be treated and analyzed as follows:
      4.2  Transfer the extract to a 100 ml volumetric  flask.
      4.3  Add 3 grams of silica gel.
      4.4  Insert magnetic stirring bar and agitate at  a rate  sufficient to
           cause continuous convection of the silica gel.
      4.5  After 10 minutes, stop the stirrer and allow the silica gel to
           settle completely.
      4.6  Carefully withdraw 10 ml of Freon extract with a syringe and
           inject it into the analyzer.
      4.7  Open extractor and discharge controls and discard effluent.
      4.8  Refill analyzer with a fresh 10 ml aliquot of extract,  open
           extractor and measure oil concentration.
      4.9  Discharge sample and repeat steps 4.4 to 4.8.  Successive readings
           of each sample should agree with 5 ppm.
      4.10 Retain remaining Freon extract in appropriately  labeled glass
           bottle and seal.
      4.11 If reading goes off scale (100 ppm) pipet 10.0 ml of extract into
           50 ml volumetric flask and dilute with Freon TF.
                                     421
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      4.12 Determine oil  concentration in diluted extract as outlined in
           4.6-4.9.
5.0   Laboratory Procedure
      5.1  Not applicable.
6.0   Calculation
      6.1  Oil-in-water concentration with silica gel  with no Freon extract
           dilution:
           ppm oil  (silica gel) = ppm (instrument reading)
      6.2  Oil-in-water concentration with silica gel  with dilution, ppm oil
           (silica  gel) = ppm x D x -=—
           uhore      n   total volume of dilution (ml)
           wnere-     u " volume of extract diluted (ml)
                      E = volume of Freon extract treated (ml)
                      S = volume of sample (ml)
      6.3  Record data in laboratory notebook.  At end of each day transfer
           data from notebook to data sheets, referring data sheet back to
           actual notebook number and page under the "page	of	"
           section  on the data sheet.
      6.4  For final data report, convert oil measurement from ppm to mg/1
           by the formula:
           oil (mg/1) = oil (ppm) x F
           Where:   F = correction factor, specific gravity of platform
                        specified oil used for Horiba calibration at 25°C.
7.0   Quality Control
      7.1  Calibration of the Horiba must be performed at least once a day.
      7.2  Successive readings of each sample should agree with 5 ppm.  The
           average of the last two readings will be reported.
      7.3  Repeat calibration procedure if a different container of Freon TF
           is used.
      7.4  The silica gel must be well sealed during storage to prevent
           moisture accumulation.
      7.5  If adsorption removes 30% of the oil, redo the analyses on the
                                     422
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           previously tested Freon extract, if enough extract remains.  If
           1-5% reduction occurs after the second treatment, use this second
           number.
VISCOSITY (ONSHORE)
1.0   Reference
      1.1  American Society for Testing and Materials, "1974 Annual Book of
           ASTM Standards, Part 23, Petroleum Products and Lubricants,"
           American Society for Testing and Materials, 1916 Race St.,
           Philadelphia, PA 19103.
           Note:  The method detailed in this section follows the Standard
                  Test Method (D 445-74) Kinematic Viscosity of Transparent
                  and Opaque Liquids exactly as given in reference 1.1.
2.0   Equipment
      2.1  Viscometer, Cannon-Fenske, ASTM-50, 100, 200, 350, calibrated.
      2.2  Stopwatch.
      2.3  Constant-temperature bath.
      2.4  Hydrometer.
      2.5  Bottle, glass 500 ml.
3.0   Calibration
      3.1  Only Cannon-type CFRC viscometers which have been calibrated by
           the manufacturer will be used.
4.0   Field Procedure
      4.1  Purge sample port.
      4.2  Fill sample bottle, seal, label, inventory and pack for shipment.
5.0   Laboratory Procedure
      5.1  Select a clean, dry calibrated viscometer that will give a flow
           time greater than 200 seconds.
      5.2  To charge the viscometer, invert the viscometer and apply suction
           to the mounting tube (large diameter)  with the upper vent tube
           (small diameter) in the liquid sample.
      5.3  Draw the sample to the second timing mark.
      5.4  Mount the viscometer upright in the constant temperature bath at
                                     423
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           same temperature with which it was calibrated, keeping the mount-
           ing tube vertical.
      5.5  Allow the viscometer to remain in the constant temperature for 10
           minutes to ensure that the sample reaches temperature equilibrium.
    1  5.6  Use vacuum to draw  the sample through the bulb to about 5 mm above
           the upper time mark.
      5.7  Release the vacuum, and allow the sample to flow by gravity.
      5.8  Measure, to the nearest 0.1 second, the time required for the
           leading edge of the meniscus to pass from the first timing mark
           to the second.  If  this flow time is less than 200 sec., select
           a smaller capillary viscometer and repeat 5.2-5.8.
      5.9  Repeat 5.6-5.8, making duplicate flow time measurements.  If the
           two measurements agree within 0.2%, use the mean for calculating
           the kinematic viscosity.
6.0   Calculation
      6.1  Calculate the kinematic viscosity, by the following:
           y = C t
           Where:   y = kinematic viscosity, cs
                    C = calibration constant of the viscometer
                    t = flow time, seconds
      6.2  Calculate the viscosity, N, by the following:
           N = p y
                    N = dynamic viscosity, cp
                    p = density, g/cm3, at the same temperature used for
                        measuring the flow time t.
      6.3  Report test results for both kinematic and dynamic viscosity
           rounded to the nearest one part per thousand.
      6.4  Record data in laboratory notebook.  At end of each day transfer
           data from notebook  to data sheets, referring data sheet back to
           actual notebook number and page under the "page	 of	"
           section on the data sheet.
7.0   Quality Control
      7.1  Use only Cannon-type CFRC viscometers which have been calibrated
                                     424
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           by the manufacturer.
      7.2  Duplicate flow time measurements will  be made.  Only duplicate
           measurements within 0.2% agreement will  be acceptable.
SUSCEPTIBILITY TO OIL SEPARATION (OFFSHORE)
1.0   Reference
      1.1  American Petroleum Institute, 1968, "API Recommended Practice
           for Analysis of Oil-Field Water," American Petroleum Institute,
           Division of Production, 300 Corrigan Tower 81dg., Dallas, Texas
           75201.
           Note:  The techniques detailed in this section follow the
                  Determination of Susceptibility to Oil Separation
                  (API Method 734-53) as listed in  reference 1.1 for
                  the 30 minute settling time.  Other settling times
                  will be employed to provide additional data.
2.0   Equipment
      2.1  6 separatory funnels, 2 liter.
      2.2  Funnel support rack.
      2.3  Bottle, glass, 1000 ml.
      2.4  Oil-in-water analyzer,  Horiba OCMA-200.
      2.5  Graduated cylinder, stoppered, 100 ml.
      2.6  Syringe, glass, 10 ul.
      2.7  Freon TF   (1,1,2  - trichloro -  1,2,2  -  trifluoroethane).
3.0   Calibration
      3.1  Inject 10 ml of Freon TF into extraction chamber.
      3.2  Turn extractor control  to the open position.
      3.3  Adjust zero control.
      3.4  Prepare 100 ppm standard by injecting  10 micro!iters of oil
           into a 100 ml volumetric flask and dilute with Freon.
      3.5  Inject 10 ml of 100 ppm standard into  extraction chamber.
      3.6  Open extraction cell and discharge sample.
      3.7  Close extraction cell and refill with  10 ml  of standard.
                                      425
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      3.8  Adjust span for 100 ppm oil.

4.0   Field Procedure

      4.1  Note and record sample stream temperature.   Purge sample port.

      4.2  Collect one "initial" sample  in a 1.0 liter bottle.

      4.3  Collect 6 two-liter samples in identical  2  liter separatory
           funnels.  As collection of each sample is completed,  record the
           time and place the separatory funnel  in the rack. The order of
           taking samples in terms of settling times will  be the 0, 120, 60,
           30, 15, 5, 2 and 0 minute samples.

      4.4  After collection of the 2-minute sample,  collect a "final"  1.0
           liter sample in a 1.0 liter bottle.

      4.5  Withdraw 1-liter samples from successive  separatory  funnels at
           intervals of 2, 5, 15, 30, 60, 120  minutes  after collection.

      4.6  Measure and record the temperature  of the water remaining in each
           separatory funnel after the 1-liter aliquot is  taken.

      4.7  Add 5 ml 6N hydrochloric acid to each sample.

      4.8  Pour the first sample into a  2-liter separatory funnel.

      4.9  Add 25 ml Freon TF to the sample bottle and rotate the bottle
           to rinse the sides.

      4.10 Transfer the solvent to the separatory funnel,  stopper and  shake
           vigorously for 2 minutes.

      4.11 Filter the solvent layer into a 100 ml volumetric flask through a
           funnel containing solvent-moistened filter  paper. An emulsion
           present in the extract may be broken by adding  a gram of sodium
           sulfate into the filter paper cone.

      4.12 Repeat steps 4.8-4.10 twice more, with additional portions  of
           fresh solvent, combining all  extracts in  the volumetric flask.

      4.13 Rinse the tip of the separatory funnel, filter  paper and funnel
           with 10-20 ml Freon TF and collect  the rinsings in the volumetric
           flask.

      4.14 Dilute the combined extracts  and washings in the volumetric flask
           to 100 ml.

      4.15 Collect this extract in a 125 ml glass bottle,  label  and use for
           subsequent analysis onboard as well as ashore.

      4.16 Dilute 10 ml of this extract to 100 ml using Freon TF.

                                     426
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      4.17 Inject 10 ml  of this Freon extract into analyzer.
      4.18 Open extractor and discharge controls and discard  effluent.
      4.19 Refill analyzer with a fresh 20 ml aliquot of extract, open
           extractor and measure oil  concentration.
      4.20 Discharge sample and repeat step 4.16.  Successive readings  of
           each sample should agree within 5 ppm.
      4.21 Retain remaining Freon extract in appropriately labeled glass
           bottle and seal.
      4.22 If reading goes off scale (100 ppm),  pipet 10.0 ml of extract
           into a 50 ml  volumetric flask and dilute with Freon TF.
      4.23 Determine oil concentration in diluted Freon  extract as outlined
           in steps 4.18-4.22.
      4.24 Proceed with  steps 4.7-4.23 for each  aliquot  which was collected
           at a different time interval.
      4.25 If the before and after 1.0 liter samples vary by  more than  20%,
           the sample series will be scrapped and a  new  set of samples  will
           be taken.
      4.26 Run an IR/silica gel on the 0, 5 and  120 minute samples.
5.0   Laboratory Procedure
      5.1  Not applicable.
6.0   Calculation
      6.1  Oil-in-water  concentration with no dilution:
           ppm oil = ppm x -1-
           Where:    ppm = instrument reading
                      E = volume of Freon extract (ml)
                      S = volume of sample (ml)
      6.2  Oil-in-water  concentration with dilution
           ppm oil = ppm x D x —i-
           ,,.          n _ total  volume of dilution  (ml)
                         " volume of extract diluted (ml)
                                     427
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      6.3  Plot the resulting concentration values  against  settling  time.
           Comparison of the resulting curve with similar curves from other
           water sources will show the relative settleability of the oil  in
           each of the water sources.

      6.4  Record data in laboratory notebook.   At  end of each day transfer
           data from notebook to data  sheets, referring data sheet back to
           actual notebook number and  page under the "page	of	"
           section on the data sheet.

      6.5  For final data report, convert oil measurement from ppm to mg/1  by
           the formula:

           oil (mg/1) = oil  (ppm) x F

           Where:   F = correction factor, specific gravity of platform
                        specific oil used for Horiba calibration,  at 25°C.

7.0   Quality Control

      7.1  Calibration must be performed at least once a day.

      7.2  Successive readings of each sample should agree within  5  ppm.   The
           average of the last two readings will be reported.

      7.3  Repeat calibration procedure if a different container of  Freon  TF
           is used.

STANDARD OILFIELD IONIC ANALYSIS (ONSHORE)

1.0   References

      1.1  American Petroleum Institute, 1968,  "API Recommended Practice  for
           Analysis of Oil-Field Water," American Petroleum Institute,
           Division of Production, 300 Corrigan Tower Bldg., Dallas, Texas
           75201.

      1.2  American Public Health Association,  1976, "Standard Methods for
           the Examination of Water and Wastewater," 14th Edition, American
           Public Health Association,  1015 Eighteenth Street NW, Washington,
           D.C. 20036.

      1.3  Environmental Protection Agency, 1979, "Methods for Chemical
           Analysis of Water and Wastes," Environmental  Monitoring and
           Support Laboratory, Environmental Research Center, Cincinnati,
           Ohio 45268.

2.0   Equipment and Reagents

      2.1  Bottles, polyethylene, 1-liter.

      2.2  Nitric acid, concentrated.

                                     428
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      2.3  Zinc acetate.
      2.4  Syringe, 10 ml.
      2.5  Bottles, glass,  1-liter.
3.0   Calibration
      3.1  Calibration procedures are specific for each method using the
           procedures listed in Table 225.
4.0   Field Procedure
      4.1  Purge sample port prior to filling sample bottles.
      4.2  The samples will  be collected, split into aliquots  and preserved
           according to the following schedule:
           Type of Analysis       Sample Volume      Preservative
           Metals                   1 liter          HMOs;  pH  2
           Cl, S04 TDS              1 liter          Cool,  4°C
           and alkalinity
           Sulfide                  1 liter          Zinc Acetate
      4.3  Seal, label, inventory and pack samples for shipment.
5.0   Laboratory Procedure
      5.1  The methods to be used for the analysis of each  major  constituent
           in oil-field water are listed in Table 225.
6.0   Calculations
      6.1  Calculations are specific for each method using  the procedures
           listed in the appropriate references cited in Table 225.
      6.2  Record data in laboratory notebook.  At end of each day transfer
           data from notebook to data sheets, referring data  sheet back  to
           actual notebook  number and page under the "page	of	"
           section on the data sheet.
7.0   Quality Control
      7.1  Quality control  aspects are specific for each method using the
           procedures listed in the appropriate references  cited  in Table
           225.
                                     429
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                     TABLE  225.  METHODS  FOR THE ANALYSIS
                    OF MAJOR CONSTITUENTS  IN OIL-FIELD WATERS

Constituent
Sodium (Na)
Potassium (K)
Calcium (Ca)
Magnesium (Mg)
Barium (Ba)
Chloride (Cl)
Sulfate (S04)
Alkalinity:
Carbonate
Bicarbonate
Total Dissolved Solids
Total Dissolved Solids
Iron, Fe (Total)
Sulfide (as H2S)
Method
Atomic absorption
Atomic absorption
Atomic absorption
Atomic absorption
Atomic absorption
Automated Ferricyanide
Automated Methyl thymol
Electrometric-titration
Calculation
Gravimetric
Atomic Absorption
lodometric Titration
Reference
EPA, pg. 273.1^
EPA, pg. 258.1
EPA, pg. 215.1
EPA, pg. 242.1
EPA, pg. 208.2
SM, pg, 613(2)
SM, pg. 628
API, pg. 8(3)
API, pg. 21
EPA, pg. 160.2
EPA, pg. 236.2
SM, pg. 499

(1) •  "Methods  for Chemical  Analysis  of  Water  and Wastes,  "U.S.  Environmental
     Protection  Agency,  Cincinnati,  Ohio,  1979.

(2)   "Standard Methods for  the  Examination  of Water and Waste Water,"  14th
     Edition,  American Public Health Association, Washington, D.C.  1976.

(3)   "API  Recommended  Practice  for Analysis for Oil-Field Waters,"  American
     Petroleum Institute, New York,  N.Y.,  1968.
                                     430
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SULFATE-REDUCING BACTERIA (OFFSHORE AND ONSHORE)

1.0   Reference

      1.1  American Petroleum Institute, 1975, "API Recommended Practice for
           Biological  Analysis of Subsurface Injection Water", American
           Petroleum Institute, Production Department, 300 Corrigan Tower
           Building, Dallas, Texas  75206.

           Note:  The technique for determination of sulfate-reducing
                  bacteria follows the "API Recommended Practice for
                  Biological Analysis of Subsurface Injection Waters
                  (API RP 38)" for the alternative technique for esti-
                  mating sulfate-reducing bacteria exactly as given in
                  reference 1.1.

2.0   Equipment and Reagents

      2.1  Thermometer, dial type, 0-100°C

      2.2  Sulfate-reducing broth with acid-etched iron nail in 10 ml serum
           bottles, sterile.

      2.3  Syringes, 1 ml, disposable, sterile.

      2.4  Portable incubator.

3.Q   Calibration

      3.1  Not applicable.

4.0   Field Procedure

      4.1  A clean sterile bottle will be used.

      4.2  The tap should be allowed to flow at  least 3 minutes at the
           sampling rate prior to collecting the sample.

      4.3  The sample should be taken in such a  manner as to preclude
           contamination from external sources as much as possible.

      4.4  The time, date, temperature, and appearance of the water should
           be recorded at the time of sampling,  and this  information should
           be included with the sample.  If possible, the total  solids, and
           or mineral  content of the water should be included.

      4.5  Transfer 1 ml of sample to a bottle containing sulfate-reducing
           bacteria media using the syringe.

      4.6  The bottle is sealed and flowed back  and forth four times to mix
           the inoculum.
                                     431
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      4.7  Using a new syringe, aseptically transfer 1 ml  from this bottle to
           a second bottle and mix as before.

      4.8  Continue this serial transfer until  a dilution  of 1 to 1,000,000
           is reached (6 tubes).

      4.9  Incubate all  tubes at a temperature within 5°C  of the recorded
           temperature of the water at time of sampling.   Samples should be
           labeled and inventoried.

5.0   Laboratory Procedures

      5.1  All  bottles should be held in incubation a minimum of 4 weeks.
           They should be examined on the third day and the end of each week
           for the appearance of sulfate-reducing bacteria, as indicated by
           intense black color.  The data will  be recorded as the highest
           dilution indicating growth, as compared to the  lowest dilution
           showing no growth.  The data will  be reported as a range in
           numbers, i.e., 100-1000 sulfate-reducing bacteria per milliliter.

6.0   Calculations

      6.1  Record data in laboratory notebook.   At end of  each day transfer
           data from notebook to data sheets,  referring data sheet back to
           actual notebook number and page under the "page	of	"
           section on the data sheet.

7.0   Quality Control

      7.1  Sulfate-reducing bacterial cultures will be prepared in duplicate.

      7.2  The sample should be cultured as soon as possible.

      7.3  The sample should be handled in such a manner as to avoid radical
           changes in temperature between time of sampling and time of
           examination of the sample.

      7.4  All  reasonable laboratory precautions will be  taken to assure
           aseptic conditions of sampling equipment.

EQUILIBRATION (ONSHORE)

1.0   References

      1.1  Environmental Protection Agency, 1979, "Methods for Chemical
           Analysis of Water and Wastes," Environmental Monitoring and
           Support Laboratory, Environmental  Research Center, Cincinnati,
           Ohio 45268.

      1.2  Operation Instructions, Model OCMA-200 Oil Content Analyzer,
           Horiba Instruments Incorporated, Houston, Texas  77092.


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2.0   Equipment and Reagents
      2.1  Flask, Erlenmeyer, 1000 ml.
      2.2  Separatory funnel, graduated, 125 ml.
      2.3  Oil-in-water analyzer, Horiba OCMA-200.
      2.4  Graduated cylinder, stoppered, 100 ml.
      2.5  Syringe, glass, 10 ul, 10 ml.
      2.6  Freon TF (1,1,2 - trichloro - 1,2,2 - trifluoroethane).
      2.7  Brine solution equivalent for particular oil field, as determined
           by the ionic analysis.
      2.8  Constant temperature bath.
      2.9  Hydrochloric acid, 6N.
3.0   Calibration
      3.1  Inject 10 ml of Freon TF into extraction chamber.
      3.2  Turn extractor control to the open position.
      3.3  Adjust zero control.
      3.4  Prepare 100 ppm standard by injecting 10 micro!iters of  oil  into
           a 100 ml volumetric flask and dilute with Freon.
      3.5  Inject 10 ml of 100 ppm standard into extraction  chamber.
      3.6  Open extraction cell and discharge sample.
      3.7  Close extraction cell  and refill  with 10 ml  of standard.
      3.8  Adjust span for 100 ppm oil.
4.0   Field Procedure
      4.1  Purge sample point.
      4.2  Fill  each sample bottle.   Seal,  label, inventory  and pack  for
           shipment.
      4.3  Two samples will  be taken for duplicate analysis.
5.0   Laboratory Procedure
      5.1  Add a long piece of clean glass  tubing to a  4000  ml  Erlenmeyer
                                     433
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     flask.  The tubing should be resting on the bottom of the con-
     tainer and extend several inches above the mouth.  Tape the tubing
     to the mouth of the flask so that it cannot move side to side.
5.2  Carefully pour 600 ml  of brine solution into one flask without
     splashing the solution onto the interior surfaces.
5.3  Dispense 2400 ml  of the test crude oil from a separatory funnel by
     allowing the oil  to slowly flow down the outside of the glass
     tubing.  The oil  flow should be slow enough that no deflection
     of the brine interface occurs.  This will  yield an oil to water
     ratio of 4 to 1.   The second flask will use the oil to water
     ratio found in the production system on the platform (formation
     ratio).
5.4  Seal  the mouth of the flask and protruding end of the tubing with
     aluminum foil.
5.5  Place the container in a constant temperature bath at 180°F (82°C).
5.6  Allow the sample  to equilibrate at temperature undisturbed for
     14 days.
5.7  Remove a small sample of water by siphoning water up the glass
     tubing.
5.8  Rinse a clean 125 ml, graduated separatory funnel with three
     successive 10 ml  portions of Freon TF and drain.
5.9  Add 30 ml Freon TF and 1.5 ml 6N HC1.
5.10 Collect 50.0 ml of equilibrated brine sample, stopper and shake.
5.11 Read the total volume of liquid and calculate the sample volume.
5.12 Shake vigorously  for 1 minute and allow to separate for 5 minutes.
5,13 Collect lower Freon TF layer in a 100.0 ml glass volumetric flask.
5.14 Extract the sample with 30 ml Freon TF twice more and add
     extracts to the volumetric flask.
5.15 Dilute the extract to 100.0 ml with Freon TF.
5.16 Inject 10 ml of Freon extract into analyzer.
5.17 Open extractor and discharge controls and discard effluent.
5.18 Refill analyzer with a fresh 10 ml aliquot of extract, open
     extractor and measure oil concentration.
5.19 Discharge sample and repeat step 5.18.  Successive readings of
                                434
-------
           each sample should agree within 5 ppm.
      5.20 Retain remaining Freon extract in appropriately labeled glass
           bottle and seal.
      5.21 If reading goes off scale (100 ppm), pipet 10.0 ml of extract
           into a 50 ml  volumetric flask and dilute with Freon TF.
      5.22 Determine oil  concentration in diluted Freon extract as outlined
           in steps 5.16 - 5.19.
      5.23 An IR-Oil w/silica gel test and a filtered brine test will be run
           on each equilibrated brine.  Methods for these tests appear else-
           where in this document.
6.0   Calculation
      6.1  Oil-in-water concentration at equilibrium with no dilution:
           ppm oil = ppm x -=-
           Where:    ppm = instrument reading
                       E = volume of Freon extract (ml)
                       S = volume of sample (ml)
      6.2  Oil-in-water concentration at equilibrium with dilution:
           ppm oil = ppm x D x -I-
                     n - total volume of dilution (ml)
                     u ~ volume of extract diluted (ml)
      6.3  Record data in laboratory notebook.  At end of each day transfer
           data from notebook to data sheets, referring data sheet back to
           actual notebook number and page under the "page	of	"
           section on the data sheet.
      6.4  For final data report, convert oil measurement from ppm to mg/1
           by the formula:
           oil (mg/1) = oil (ppm) x F
           Where:   F = correction factor, specific gravity of platform
                        specific oil used for Horiba calibration, at 25°C.
7.0   Quality Control
      7.1  Calibration of the IR analyzer must be performed at least once
           a day.
                                     435
-------
      7.2  Successive readings of each sample should agree within 5 ppm.
           The average of the last two readings will  be reported.
      7.3  Repeat calibration procedure if a different container of Freon
           TF is used.
FILTERED BRINE (OFFSHORE)
1.0   Reference
      1.1  This procedure follows the sample collection procedures commonly
           employed by those oil  companies using the method,  and have shown
           good results and are preferred.  (Carl Dimon, Mobil Oil,  personal
           communication, 1979).
2.0   Equipment and Reagents
      2.1  Filter paper, Whatman  No.  40,  24 cm.
      2.2  Glass funnel with internal  ribs and short stem, 100 mm diameter,
           100 mm stem.
      2.3  Graduated cylinder, stoppered,  100 ml.
      2.4  Separatory funnel, graduated,  125 ml.
      2.5  Oil-in-water analyzer, Horiba  OCMA-200.
      2.6  Syringes, glass 10 ul.
      2.7  Freon TF  (1,1,2 - trichloro -  1,2,2 -  trifluoroethane).
      2.8  Crude oil.
      2.9  Volumetric flask 100 ml, 50 ml.
      2.10 Hydrochloric acid, 6N.
      2.11 Dispenser, glass, 50 ml.
      2.12 Bottle, glass, 125 ml.
      2.13 Deionized water.
3.0   Calibration
      3.1  Inject 10 ml of Freon  TF into  extraction chamber.
      3.2  Turn extractor control to  the  open position.
      3.3  Adjust zero control.
                                     436
-------
      3.4  Prepare 100 ppm standard by injecting 10 micro!iters of oil into
           a 100 ml volumetric flask and dilute with Freon.
      3.5  Inject 10 ml of 100 ppm standard into extraction chamber.
      3.6  Open extraction cell and discharge sample.
      3.7  Close extraction cell  and refill with 10 ml  of standard.
      3.8  Adjust span for 100 ppm oil.
4.0   Field Procedure
      4.1  Wet filter with deionized water.
      4.2  Put funnel stem into graduated cylinder.
      4.3  Purge sample flow line.
      4.4  Put funnel under sample cock and fill the funnel with brine.
           (Note:  The funnel  holds about 100 cc.)
      4.5  Filter long enough  to  collect 25 to 50 ml of filtrate.  There is
           no need to wait for all the sample to filter.
      4.6  Remove the funnel,  replace the cap; sample is ready for analysis.
      4.7  Rinse a clean 125 ml,  graduated separatory funnel with three
           successive 10 ml portions of Freon TF and drain.
      4.8  Add 50.0 ml Freon TF and 1.5 ml 6N HC1.
      4.9  Collect 50 ml of aqueous sample, stopper and shake.
      4.10 Read the total volume  of. liquid and calculate the sample volume.
      4.11 Shake vigorously for 1 minute and allow to separate for 5 minutes.
      4.12 Collect lower Freon TF layer in a glass beaker.
      4.13 Inject 10 ml of Freon  extract into analyzer.
      4.14 Open extractor and  discharge controls and discard effluent.
      4.15 Refill analyzer with a fresh 10 ml  aliquot of extract, open
           extractor and measure  oil  concentration.
      4.16 Discharge sample and repeat step 4.15.  Successive readings of
           each sample should  agree within 5 ppm.
      4.17 Retain remaining Freon extract for additional analysis in
                                     437
-------
           appropriately labeled glass bottle and seal.
      4.18 If reading goes off scale (100 ppm), pipet 10.0 ml  of extract
           into a 50 ml  volumetric flask and dilute with Freon TF.
      4.19 Determine oil concentration in diluted Freon extract as outlined
           in steps 4.13-4.16.
5.0   Laboratory Procedure
      5.1  Not applicable.
6.0   Calculation
      6.1  Oil-in-water concentration with no dilution:
           ppm oil  = ppm x -|-
           Where:    ppm = instrument reading
                       E = volume of Freon extract (ml)
                       S = volume of sample (ml)
      6.2  Oil-in-water concentration with dilution:
           ppm oil  = ppm x D x -4-
           Where: Q _ total volume of dilution (ml)
                     volume of Freon extract di1uted (ml)
      6.3  For final data report, convert oil measurement from ppm to mg/1
           by the formula:
           Oil (mg/1) = oil (ppm) x F
           Where:   F = correction factor, specific gravity of platform
                        specific oil used for Horiba calibration at 25°C.
7.0   Quality Control
      7.1  Calibration must be performed at least once a day.
      7.2  Successive readings of each sample should agree within 5 ppm.  The
           average of the last two readings will be reported.
      7.3  Repeat calibration procedure if a different container of Freon
           TF is used.
                                      438
-------
IR SCAN OF FREON EXTRACTS (ONSHORE)

1.0   Reference

      1.1  Environmental  Protection Agency, 1976, "Methods for Chemical
           Analysis of Water and Wastes," Environmental  Monitoring and
           Support Laboratory, Environmental  Research Center, Cincinnati,
           Ohio 45268.

2.0   Equipment and Reagent^

      2.1  IR spectrophotometer (Perkin-Elmer Model  621).

      2.2  Bottles, glass.

3.0   Calibration

      3.1  Not applicable.

4.0   Field Procedure

      4.1  All remaining Freon extracts from field IR analyses will be
           appropriately labeled, sealed, inventoried and packed for
           shipment.

5.0   Lab o ra to ryJ3rpeedure

      5.1  If preliminary field data indicate the true concentration of oil
           in the Freon extract is only a few ppm, then the resulting IR
           scans may not be definitive.  If this is the case, all effluent
           IR extracts from a given platform will be combined.  The combined
           extracts will  be evaporated to a small volume using a Kuderna-
           Danish concentrator and an IR scan on the residue will be run.
           In addition, all solvent may have to be removed to obtain a
           sufficient scan.

      5.2  Run IR spectra (4000-650cm~ ) on samples from oil fields showing
           highly soluble components.

6.0   Calculations

      6.1  Not applicable.

7.0   Quality Control

      7.1  Crude oils contain hydrocarbon bonds with a strong absorption
           band in the 2930 crrT^ region.  Caution must be exercised in the
           selection of the 2930 cm'1 peak, as it may not always be the
           largest peak in that region.  Several scans may be needed to
           provide sufficient detail allowing some peaks to go off scale.
                                     439
-------
                                 APPENDIX B

                   QUALITY ASSURANCE/QUALITY CONTROL PLAN


QUALITY ASSURANCE/QUALITY CONTROL ANALYTICAL METHODOLOGY

Oil and Grease IR

     All glassware used in the collection, extraction and analysis of samples
for oil and grease concentrations by infrared analysis was cleaned prior to
processing of each sample.  The glassware was washed and brushed with soapy
tap water, rinsed with tap water and then with deionized water several times,
and finally rinsed with three portions of Freon TF.  Particularly oily glass-
ware was rinsed with methyl ethyl ketone before washing with tap water.
Acetone rinses were avoided at all times due to the limited solubility of
acetone in Freon TF.  Once clean, the glassware was sealed and set aside until
needed.  Immediately before use, all glassware was again rinsed with a small
portion of Freon TF.  The Freon rinse was drained directly into the Horiba IR
analyzer and the concentration of hydrocarbons was measured.  If a significant
reading (>5 ppm) was obtained, the glassware was again rinsed with Freon until
acceptable readings were obtained.  Once a reading of <5 ppm was obtained,
the glassware was immediately put to use.

     Instrument responses over the range of 0 to 100 ppm were verified as
linear for each Horiba OCMA-200 used in Phase I.  All three IR analyzers were
found to be statistically linear within that working range (Table 226).  In
all cases percent agreement ranged from 98 - 105%.  Least squares linear
regression analyses yielded significant correlation between standard values
and analyzer readings for all three units.  Calibration of the instrument in
the field was performed prior to daily analysis and checked at the end of
each day.

     Once the IR analyses were completed, the remaining sample was retained
for subsequent laboratory processing.  Samples were reanalyzed after return
to the TI Dallas Laboratories to verify preliminary field data.  All Phase I
field readings were verified correct by reanalysis before the data were
reported to C-E Crest.   Selected Phase II results were rechecked.

     During field analysis, when a new container of Freon TF was opened for
use, the IR analyzer was recalibrated using the new Freon sample and a sample
of the Freon was collected and analyzed for contamination using the previous
Freon as a standard reference.
                                     440
-------
          TABLE 226.  RESULTS OF LINEARITY TEST FOR HORIBA OCMA-200

Analyzer readings (ppm)
Unit
number
1





Standard
concentration
0
20
40
60
80
100
Trial
1
0
21
39
60
32
100
Trial
2
0
21
40
60
82
100
Trial
3
0
21
40
60
82
100
Mean
value
0
21
39.7
60
82
100
%
Agreement
100
105
99
100
102
100
                 0
                20
                40
                60
                80
               100

                 0
                20
                40
                60
                80
               100
  0
 21
 38
 59
 80
100

  0
 21
 40
 60
 82
100
  0
 21
 39
 59
 80
100

  0
 21
 40
 60
 82
100
  0
 21
 39
 59
 80
100

  0
 21
 40
 60
 82
100
  0
 21
 38.
 59
 80
100

  0
 21
 40
 60
 82
100
100
105
 99
 98
100
100

100
105
100
100
102
100
Oil and Grease - Gravimetric

     All glassware used in the collection, extraction and analysis of samples
for oil and grease concentrations by gravimetric procedures was treated in
the same manner as was used for oil  and grease by infrared analysis.

     Blank determinations were made  using the same batch of Freon TF  used in
the field extractions.  Each time a  new batch of Freon TF was used, a Freon
blank was collected for later analysis.  Each gravimetric sample was  corrected
for solvent by processing blanks.

Temperature

     Water samples were taken from the effluent stream after the samole port
had been purged for several  minutes.  The water was collected in a 500-ml
plastic beaker and shielded from winds while the temperature reading  was made.
The normal  time span between sample  collection and temperature reading was
2-3 minutes.  Given the heat capacity of the brine solution, little heat loss
could be expected in this short time interval.  It is expected that the system
temperature data adequately represent actual system temperatures.
                                    441
-------
JDH

     The pH data were collected with a battery operated pH meter using a
combination electrode.  The system was calibrated with a pH 6.86 standard
buffer immediately prior to use.  The response of the combination electrode
over the pH range 4.01 - 9.18 was tested every other day using three standard
buffers.  If the response did not agree with the Nernst slope response
within 95%, the electrode was replaced and the process was repeated.
Temperature and pH data were taken at the same time.

Boiling Range Distribution

     A Perkin-Elmer Sigma 2 gas chromatograph equipped with a flame ionization
detector was used in the determination of crude oil  boiling range distribu-
tion.  Data were collected with a Perkin-Elmer Sigma 10 chromotoqraphy data
station.  All quality control criteria as established in ANSI/ASTM Standard
Test Method D22887-73 were followed.  Samples were analyzed several times to
produce a chart output which was used to aid in the interpretation of the
crude oil equilibration test results.

Specific Gravity, Oil and Water

     The hydrometers used in the measurement of both crude oil and brine
specific gravities were ASTM recommended design.  The hydrometers in the
0.800 - 0.900 and the 1.0 - 1.25 g/cm3 range were corrected for the surface
tension effect to determine actual principal surface height from the hydro-
meter readings by using a transparent fluid with surface tensions similar
to those expected for crude oil and brine.  These correction factors were
applied to all field data collected.  All fluid samples were allowed to reach
thermal equilibrium in the hydrometer cylinders before readings were made.
Temperatures at which readings were made were recorded in field notebooks.

Water Cut

     API design centrifuge tubes were used with a hand powered centrifuge.
Centrifuging was repeated until consecutive readings agreed within Q.2%.

Suspended Solids

     All suspended solids samples were collected with Teflon in-line filter
holders so that no oxidation-produced particulate material  would prejudice
the suspended solids data.  The filters were carefully removed from the
holders, placed in individual plastic petri dishes, and frozen to retard
evaporative or bacterial alteration of the collected material.  Separate
blank filters were used to correct for field and laboratory contamination
during processing.  All blank filters were handled in an analogous manner to
suspended solids filters except that no filtration was conducted.  The^
suspended solids data were corrected for process contamination prior to
being reported to C-E Crest.
                                     442
-------
Surface Tension

     The surface tensiometers employed for testing were ASTM design and all
required quality control procedures and calibration procedures were followed
as specified in Standard Test Method D1590-60 (1977).  Tensiometers were
calibrated daily while onboard the platforms; records of calibration data
were kept in field notebooks and in the tensiometer calibration log.

Silica Gel Adsorption

     All glassware used in the collection, extraction and analysis of samples
for silica gel-adsorfaable hydrocarbons in the Freon extracts was treated in
the same manner as previously detailed for oil and grease by infrared
analysis.  The silica gel portions were sealed in capped polypropylene vials,
but this did not prevent moisture deactivation of the silica gel while off-
shore.  Because of this deactivation problem, some silica gel adsorption
tests were redone in the TI Dallas laboratories.

Crude Oil Equilibration

     All glassware used in the collection, extraction and processing of
samples for infrared analysis of crude oil equilibration tests was treated
in the same manner as done for oil and grease concentrations by infrared
analysis.  Duplicate 14-day incubations were conducted, duplicate samples
were drawn from the incubation flasks, IR analyses were performed and the
results were averaged to produce a single oil and grease concentration value
for each incubation.  For each platform two crude oil equilibration values
were reported.

     Each of the Freon extracts was analyzed by gas chromatography to
establish a finger print of the Freon-extractable material.   This was then
compared to the gas chromatographic analyses made for the boiling range
distribution determinations done for each crude oil sample to assess the
possibilities of solubilization versus dispersion/suspension of crude oil
droplets in the brine solution.

Filtered Brine

     All glassware used in the collection, extraction and analysis of filtered
brine samples was treated in the same manner as previously detailed for the
analysis of oil and grease concentrations by infrared analysis.

IR Scan of Addition Chemicals and Freon Extracts

     Standard laboratory procedures were employed in  the preparation of
infrared scans of addition chemicals and Freon extracts.  For some solutions,
several scans were needed to provide sufficient detail to determine charac-
teristic functional  groups.

Viscosity

    .The viscometers used in Phase I analyses were ASTM type and were

                                     443
-------
calibrated by the manufacturer.   Duplicate flow time measurements were made;
agreement within 0.2% was required for adequate reoortinq retirements.  The
mean value of the two measurements was reported.

Susceptibility to Oil Separation

     All glassware used in this  determination was treated in the same manner
as previously detailed for the analysis of oil and grease concentrations by
infrared analysis.  Replicate tests were made on  each platform;  duplicate
tests were not made.   The time interval between replicate testing was several
days.

Standard Oilfield Ionic Analysis

     Quality control  procedures  specified by EPA, APHA,  and API  in the
applicable references for each test were followed.  Individual  samples were
preserved for metal  analyses by  acidification to  pH 2, samples  for chloride,
sulfate, TDS and alkalinity analyses were cooled  to 4°C  and sulfide samples
were preserved with  2 ml zinc acetate solution.

Bacterial Culture:  Sulfate-Reducing Bacteria

     Sulfate-reducinq bacterial  cultures were prepared in duplicate.   The
samples were cultured at ± 5°C from system temperature as soon  as possible
after collection.  Radical changes in temperature were avoided  between time
of sampling and time of examination of the culture.  Sterile equipment was
used throughout; sample bottles  were resterilized immediately prior to use
to ensure sterile conditions at  the start of samolings.   Blank  cultures were
incubated with the platform samples to provide a  check on the samole bottle
integrity during incubation.

QUALITY ASSURANCE/QUALITY CONTROL CHAIN-OF-CUSTODY PROCEDURES

     Prior to initial sampling (Day 01) at each platform, all  sample oorts
were located and identified to TI oersonnel  by the platform operator; TI
personnel tagged the valves with numbered designation labels (Figure 123)
so that the appropriate system ports were consistently sampled.   For each
platform, using TI's Analysis Program Plan,  a daily sampling log was
prepared detailing the hourly sampling schedule (Figure  124).   An "X",
placed in the appropriate row and column, designated a scheduled sample
collection.  Once the sample was collected,  the analyst  circled  the "X"
and initialed the entry (Figure  125).  One-time samples  were logged in by
placing an "X" in the appropriate row and column  on the  checklist, circling
and initialing the entry.

     After the sample had been collected and properly logged, it was processed
according to the field SOP written from TI's Analysis Program Plan.  Data
collected onboard the platform (meter readings, temperatures, volume measure-
ments, etc.) were entered into standard TI numbered, and hardbound analytical
notebooks (Figure 126).  Once a  page was filled,  the analyst dated and signed
the page as did the Field Team Supervisor to witness entries and acknowledge
understanding of the page contents (Figure 127).

                                     444
-------
     5A30
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             9--0
            SP65B
Figure 123. Sample port designation labels
           445
-------
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Figure 127.   Example of a completed page of a notebook
                used in Phase I research.
                          449
-------
Field data were extracted from the notebook and entered onto TI form 24809
Project-Specific Data Sheet (Figure 128) at the end of each olatform workday.
The appropriate page numbers of the notebook were entered on the data sheet;
the person filling out the data sheet signed and dated the sheet; the TI
Program Manager checked the entries for accuracy, and signed and dated the
sheet attesting to accuracy of data transfer (Fiaure 129).

     For field equipment requiring periodic calibration, calibration logs
were maintained (Figure 130).   Once the calibration or response verification
was complete and recorded in the field notebook the analyst entered the ao-
propriate data in the calibration logs.  This procedure was followed for the
IR analyzers, tensiometers and pH meters.  The Field Team Supervisor
verified all calibration log entries and signed the log at completion of each
calibration.

     Samples that were to be collected and then processed ashore, or samples
that were processed onboard the platforms that were to be preserved for future
onshore analyses, were preserved in the appropriate containers and labeled
(Figure 131).  Smaller labels  were used on all  crude oil, oil  and grease, and
addition chemical  samples, while larger labels were used on all other samples.
Table 227 lists labeling instructions provided by TI's field SOP.

     After the research was comoleted on each platform, all samples scheduled
to be returned to TI's Dallas  analytical laboratories were shipoed either by
automobile or via airplane.  Each shipment was accompanied by a TI courier.
All field and laboratory samples were placed in locked aluminum shipping
containers.   All samples were  inventoried on TI General Ecology Samole/Data
Progress Sheets, TI form 23123 (Figure 132).   Inventory sheets were placed
inside the shipping containers.  The contents of the shipment were summarized
on a General Ecoloay Data/Displays Progress Sheet, TI form 23120A
(Figure 133),  and it was carried seoarate from the containers.  All sample
logs, analytical notebooks, field data sheets, calibration logs and samole
inventory sheets were received, signed for, hand-carried to Dallas by the TI
courier and delivered to the TI Program Manager upon arrival in Dallas.   The
Program Manager signed for these materials.  All  written documentation was
placed in locked program files as part of the permanent project documentation.

     Upon receipt of the sample shipment in the Dallas analytical laborato-
ries, the courier turned over  the keys to the shipping containers to the
laboratory manager who signed  for receipt of the shipment.  The shipping
containers were opened, the contents were inventoried and checked for
physical damage.  The laboratory inventory was then checked aqainst the field
inventory.  Accuracy in all cases was absolute.  Once the inventory was
verified correct, each sample  bottle was assigned a laboratory processing
number unique to that sample (not project-specific).  All samples were
processed according to a laboratory SOP prepared from TI's Analysis.
Program Plan.

     Laboratory data were reported to the TI Program Manager on TI form
24809 (Figure 128), the same type of data sheet utilized for reporting of
the field data.  Field and laboratory data were checked for transcription or


                                     450
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                       454
-------
                       TABLE 227.   LABELING INSTRUCTIONS
Field labels shall  be filled out as follows:
                   Proj.  No.:
                   Sample No.:

                   Task:
                   Gear:

                   Sample Date:
                   Contents:

                   Location:

                   Split:
   8931
   Location sample taken from
   (Number from sample schedule.)
   Day of samp!ing 1-10
   Hourly sample
   [0800, 1000, 1300, 1500)
   Date Collected
   Freon
   Water
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   SP65B
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   Undiluted
                        of
number
of total
                                     455
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                                           456
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Figure 133.  TI form 23120A, general ecology data/
              displays progress sheet.
                        457
-------
entry errors and were transferred to the appropriate C-E Crest data sheets
(Figures 134 to 137).  TI field and laboratory data sheets were placed in
locked program files as part of the permanent project documentation; C-E Crest
data sheets were transferred with cover letter to the C-E Crest Program
Manager who assumed all data processing responsibilities for the program.
Copies of the C-E Crest data sheets were maintained in the TI program files
as part of the permanent documentation.
                                     458
-------
               CREST
                                                  Tl  FIELD  ANALYTICAL DATA  SHEET
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                                    Figure  134.   C-E Crest, TI field  analytical  data sheet.
-------
EaJlCRE!
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-------
            EiL^ CREST
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                              Figure 136.  C-E Crest,  Tl  laboratory analytical data  sheet.
-------
                tCREST
                                                       IONIC ANALYSIS TEST SHEET
cn
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                                   Figure 137.  C-E Crest,  ionic analysis test  sheet.
-------
                                  GLOSSARY
API gravity:  The measure of the gravity of liquid petroleum products derived
     from specific gravity in accordance with the following equation:


               API S™1** '   specif"'gravity   -131'5

choke:  A type of orifice installed in a line at the wellhead to restrict the
     flow and control the rate of production of oil or gas.

corrugated plate interceptor:  A gravity separator in which the fluid flows
     between corrugated parallel plates.  Oil must rise only short distances
     by gravity to contact the plates.

dispersed oil:  As defined for this report, the non-polar material  extracted
     from brine by Freon and not adsorbed by silica gel from the Freon as
     part of the IR-Oil w/Silica Gel test.

flotation, dispersed gas:  A process for separating oil from water in which
     mechanically or hydraulically dispersed gas bubbles adhere to oil drop-
     lets and rise rapidly for separation by skimming.

flotation, dissolved gas:  A process for separating oil from water in which
     gas bubbles formed when pressure is reduced on a gas-saturated solution
     adhere to oil droplets and rise to the surface for oil removal by
     skimming.

flowing tubing pressure:  The pressure in the tubing at the wellhead of a
     flowing well.

flowing well:  A well that produces oil or gas by its own reservoir pressure.
     A well that does not employ pumps or other artificial lifting means.

free water knock out:  A vertical or horizontal vessel into which oil or
     emulsion is run to allow water that is not emulsified with the oil to
     drop out.

gas lift:  The process of raising fluid from a well by means of gas injected
     down the well through tubing or through the tubing casing annul us.
     Injected gas reduces the weight of the fluid so that the formation
     pressure forces the fluid out of the wellbore.
                                    463
-------
                            GLOSSARY (continued)

gas-oil ratio (GOR):  A measure of the volume of gas produced with oil;
     expressed in cubic feet per barrel  or cubic meters per metric ton.

gravity separator:  A vessel in which oil  and water are separated by settling
     as the result of specific gravity differences.  In this report, it
     refers primarily to the gravity separation step used specifically to
     remove oil  from brine in preparation  for flotation.

gun barrel:  A settling tank used in separating oil and water in the field.
     In this report, all gun barrels had round inlet pipes extending down-
     ward in the center of the tank and  operated at atmospheric pressure.

heater treater:   A vessel in which oil,  water, and emulsions are placed to
     remove water and gas, and render oil  of acceptable quality to a pipe-
     line.  Heater treaters are a combination of a heater, a free water knock
     out, and an oil and gas separator.

hydraulic loading:  Hydraulic loading is the volumetric flow through a treat-
     ing vessel.  In this report, stated in terms of flow rate, percent of
     design flow rate, and overflow rate.

overflow rate:  The surface area divided by the flow rate through a gravity
     separator or treating vessel.

shut in bottom hole pressure:  The pressure existing at the bottom of a well
     when the surface valves are closed.

skim tanks:  Gravity oil/water separation  tanks with various shapes and flow
     patterns.  In this report, all skim tanks operated at atmospheric pres-
     sure with a controlled surface level.

soluble oil:  As defined for this report,  the polar materials that are ex-
     tracted from brine by Freon and then  are adsorbed by silica gel from
     the Freon as part of the IR-Oil w/Silica Gel test.

test separator:   An oil and gas separator  employed to separate relatively
     small quantities of oil and gas which are diverted through the testing
     device on a lease.

three-phase separator:  A separator employed to separate oil, gas, and water
     by gas/liquid phase separation and oil/water specific gravity difference,

two-phase separator:  A separator employed to separate oil and water from gas,

treatability:  As defined for this report, the lowest oil content to which a
     brine could be treated by physical  processes as indicated by the IR-Oil
     w/Silica Gel test.
                                     464
-------
                             GLOSSARY (continued)
water cut:  The proportion of water in produced fluids.  In this report,
     stated in percent as determined by ASTM Method 01796-68 (1973).
wellhead:  The equipment used to maintain surface control  of a well.
                                     465
-------
TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing]
1 REPORT NO. |2.
4. TITLE AND SUBTITLE
Oil Content in Produced Brine on Ten Louisiana Production
Platforms
7. AUTHOR(S)
George F. Jackson, Eugene Hume, Michael 0. Wade and
Milton Kirsch
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Crest Engineering Inc.
P.O. Box 1859
Tulsa, OK 74101
12. SPONSORING AGENCY NAME AND ADDRESS
Municipal Environmental Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, OH 45268
3. RECI-'iTNT'S ACCESSIOONO.
5. REPORT DATE
6 PERFORMING ORGANIZATION CODE
8. PERFORMING ORGANIZATION REPORT NO
10. PROGRAM ELEMENT NO.
1NE823 :
11. CONTRACT/GRANT NO.
68-03-2648
13. TYPE OF REPORT AND PERIOD COVFRED
Final
14. SPONSORING AGENCY CODE
EPA/600/14
15. SUPPLEMENTARY NOTES
John S. Farlow, Project Officer (201-321-6631)
 .G. ABSTRACT
     A survey of the oil content  of  brine  effluents  from offshore crude oil production
 Jlatforms was conducted for  the Oil  and  Hazardous  Spills Branch of the Environmental
 Yotection Agency.  The objectives were  to determine the amount of oil in the brine,
 jnd to determine the factors  affecting brine oil  content variability.
     Ten-day surveys were conducted  on ten platforms.   The platforms selected repre-
 ented a wide range of characteristics with respect  to produced fluids, processing
 ystems, and water treating  systems.  Each platform  had a flotation unit for final oil
 eparation before discharge.
     Minimums of forty gravimetric and twenty infrared oil  content tests were run on
brine effluents of each platform.  Oil content tests were also run at upstream points
in the systems.  Other brine  tests run for correlation with effluent oil content
included:  soluble oil, oil  drop-size distribution,  suspended solids, surface tension,
ionic analysis, pH, specific  gravity, surface tension, boiling point distribution, and
temperature.
     Records were kept of operational factors including:  water cuts, lift methods,
pressures, chemical addition  programs, and hydraulic loading of water treating units.
     Test data and operational data  were analyzed  for  correlation with effluent oil
content data.
17.
                               KEY WORDS AND DOCUMENT ANALYSIS
                  DESCRIPTORS
   Oil  Recovery
   Environmental  Engineering
   Water  Pollution
   Water  Treatment
   Oils
                                              b.IDENTIFIERS/OPEN ENDED TERMS
Produced Water  Treatment
Unit Process  Efficacy
Chem. Analytical  Methods
Brine Oil  Content Vari-
  ability
                          c.  COSATl Field/Group
18. DISTRIBUTION STATEMENT
    Release  to  Public
                                              19. SECURITY CLASS (This Report/

                                              UNCLASSIFIED
                           21. NO. OF PAGES

                              494
20. SECURITY CLASS (This page I

UNCLASSIFIED
                                                                        22 PRICE
EPA Form 2220-1 (9-73)
                                            466
-------