United States
Environmental Protection
Agency
Municipal Environmental Research
Laboratory
Cincinnati OH 45268
Research and Development
EPA-600/S2-81-200 Oct. 1981
Project Summary
Field Test Kit for Oil-Brine
Effluents from Offshore
Drilling Platforms
R. T. Rewick, J. Gates, K. A. Sabo, T.-W. Chou, and J. H. Smith
This research program was initiated
to evaluate test methods for charac-
terizing oil-brine effluents from off-
shore oil production platforms and to
deliver to the U.S. Environmental
Protection Agency (EPA) a field test
kit for onsite oil-brine analyses. After
an initial laboratory evaluation and
selection of test methods and equip-
ment, two onsite oil-brine analyses
were conducted in Kenai, Alaska—one
at the AMACO Dillon Offshore Pro-
duction Platform, and the other at the
Shell MGS Joint Onshore Facility.
This Project Summary was devel-
oped by EPA's Municipal Environ-
mental Research Laboratory, Cincin-
nati, OH, to announce key findings of
the research project that is fully
documented in a separate report of the
same title (see Project Report ordering
information at back).
Introduction
Offshore drilling facilities are be-
coming increasingly numerous as new
oil reserves are needed to replace
depleted land-based sources. As a
result, the potential for drilling and
production accidents such as the Santa
Barbara Channel disaster are also
expected to increase. Another pollution
concern is the presence of brine in the
crude oil obtained from deep-well
drilling sites. On offshore platforms, the
crude oil is routinely passed through an
oil/water/gas separator, and the brine
is then discharged into the ocean. After
varying degrees of additional treatment,
this brine contains a fine suspension of
oil droplets that is not removed in the
separator. Inefficient bfine treatment
could result in a serious contamination
source.
As one phase of a U.S. Environmental
Protection Agency (EPA) contract with
Exxon Research and Engineering, a
study was made of pollution control
technology for offshore drilling and
production platforms, and test methods
were recommended for characterizing
oil-brine effluents.1
The Offshore Operator's Committee
(OOC) reviewed the Exxon procedures
and recommended several modifica-
tions.2 Additional changes have been
proposed and verified through field
evaluation by Texas Instruments Incor-
porated.3 A summary of the OOC test
methods is given in Table 1.
This project was initiated as a means
for evaluating the OOC methods and for
developing a field kit for onsite oil brine
analysis. Specifically, this work, con-
ducted by Stanford Research Institute
(SRI), has consisted of the following
tasks:
1. Evaluate the OOC-modified test
methods (Table 1, Status 1) for
characterizing oil-brine effluents
from offshore oil production facil-
ities.
2. Recommend and package into a
field test kit suitable equipment
and instrumentation for conducting
the oil-brine characterizations.
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Table 1. OOC Test Methods for Characterizing Oil-Brine Effluents
Test
No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
Test
Oil-in-water
Suspended so/ids
Particle size
Surface tension
Viscosity
Specific gravity
Salinity
pH
Temperature
Brine composition
Bacterial culture
Oil separation
Soluble materials
Flow rate
Method/Apparatus
Gravimetric; infrared
Filtration
Microscopy
Tensiometer
Ostwald; Brookfield
Centrifuge; hydrometer
Centrifuge; titration
pH meter
Thermometer
Atomic absorption
API RP-38
API 734-53
Column and SiOz adsorption;
spectrophotometry
Shell PSM
Method
Status*
1
3
1
3
3
2
3
3
3
2
2
2
1
2
Type of Test
Field
Lab
Field
Field
Field
Field
Field
Field
Field
Lab
Lab
?
Field
Field
*Status 1: OOC-modified: Evaluate at SRI.
Status 2: OOC-modified: Standard procedures.
Status 3: OOC-approved: Standard procedures.
3. Evaluate the field test kit at a
suitable onshore or offshore oil
production facility.
4. Del iver the field test kit to EPA with
detailed instructions for performing
the tests.
Evaluation and Selection of
OOC Methods for Test Kits
The OOC-recommended test proce-
dures, a brief description of them as
suggested by the Texas Instruments
report,3 and our recommendations and
modifications are summarized in Table
2. Tests of these OOC methods were
conducted on JuJy 7,1980, at the Dillon
offshore production platform. Platform,
Kenai, Alaska, and on July 8, 1980, at
the Shell MGS Joint Onshore Facility,
Kenai, Alaska. Water samples were
withdrawn for analysis from the final
production water stream before dis-
charge into the ocean. Field results
were generally replicated three times
during the 8-hour testing period.
Recommended Tests
The following OOC tests (Table 2) are
included in the field test kit:
(1) Oil in water (infrared and gravi-
metric)
(2) Soluble materials (equilibration
and filtration)
(3) Specific gravity
(4) pH
(5) Temperature
(6) Suspended solids
(7) Bacterial culture (includes labora-
tory evaluation of samples col-
lected in the field)
The following tests are recommended
to be performed onshore in the laboratory
because vibration on the platform
interferes severely with the method:
(1) Surface tension
(2) Viscosity
Containers for collecting the required
samples are included in the test kit.
Tests Not Recommended
The following OOC test procedures
were not included in the SRI test kit:
(1) Infrared oil-in-water using the
Horiba* and Turner spectro-
photometers
(2) Gravimetric oil-in-water using
balance at test site
(3) Particle size
(4) Brine composition
(5) Flow rate (site-specific equipment
for each platform should be used
for these measurements)
(6) Water cut
(7) Boiling range
Selection and Comparison of
Oil Analysis Methods
Infrared Method—Three spectro-
scopic oil-in-water analyzers were
compared for field application: the
Horiba, Model OCMA-200; the Wilks
Miran, Model 1A-FF; and the Turner
Spectronic, Model 350. Tests showed
(Table 3) that the Miran spectropho-
tometer provides more reproducible
•Mention of trade names or commercial products
does not constitute endorsement or recommenda-
tion for use.
results and is the instrument of choice
for the infrared method. This analyzer is4
powered by 120 VAC and can probably*
be obtained as a battery-powered
model; but it is not explosion-proof.
Gravimetric Method—Table 4
compares the infrared and gravimetric
methods for analysis of oil in seawater.
For the comparison, we chose to use No.
6 fuel oil because of the unavailability of
crude samples with similar properties to
the oil from the Alaskan production
sites. We assumed that methods devel-
oped with No. 6 fuel oil should be
applicable to crude oil samples. For a
sample of Freon 113 containing a
known weight of No. 6 fuel oil, the
gravimetric method, which involved
evaporation of the Freon and weighing
of the residuals, gave 95% recovery of
the oil. These results suggest that some
volatiles (5%) are lost during evaporation.
In extraction experiments, however, the
oil recovery by both the infrared
(extraction and measurement by the
Miran) and gravimetric (extraction,
evaporation, and weighing) methods is
significantly lower, presumably because
of the poor extraction efficiency of Freon
113.
Solvent Extraction Efficiency
As shown in Table 5, CC1« is mor
efficient than Freon 113 in dissolvin
No. 6 fuel oil suspended in seawater.
With Freon 113, small black flakes of
residual material remain undissolved.
We also observed that the purity of
the Freon used in the extraction process
affects the oil analysis results. The
absorbence background for Freon TF (an
impure grade of Freon 113) was
considerably greater than spectral
grade Freon 113; a nonlinear calibration
curve for No. 6 fuel oil was observed
with the impure solvent. Since the
nonlinear calibration is less sensitive to
small differences in oil content, we
suggest that more accurate results
could be obtained using the higher-
priced Freon 113.
Test Kit Performance
The test kit evaluated and assembled
at SRI performed satisfactorily at the
two test sites. Only minor modifications
to the test procedures were required.
Approximately 8 labor-hours are re-
quired to conduct one onsite oil-brine
characterization.
During this study, it became apparent
that the complete field test kit is rather
bulky (132.3 Ib) for one person to
-------
Table 2.
Test No.
la*
Ib*
2a
2b*
2c*
3
4*
5*
6*
7*
8*
9
10*
11
12*
13
14
15
Recommended and Modified Procedures for the Field Test Kit
Test Tl Method* Reason for Test
Oil-in-water. infrared
Oil-in-water,
gravimetric
Soluble materials,
silica gel
Soluble materials.
equilibration
Soluble materials,
filtration
Particle size
Surface tension
Viscosity
Specific gravity
pH
Temperature
Brine composition
Bacterial culture
Oil separation
Suspended solids
Flow rate
Water cut
Boiling range
Filtered Freon extract
analyzed with the Horiba
Balance in lab
Silica gel in Freon extract
analyzed with Horiba
Lab with no agitation
Filter water, then analyze
with the Horiba
Continuous flow
microscope assembly
DuNouy ring tensiometer
Cannon-Fensk kinematic
Hydrometers
Battery-operated pH meter
Dial thermometer
Assorted methods (lab)
Serial dilution
Rise time of oil measured in
separatory funnel
Filter holders
Clampitron flowmeter
Centrifugation
GC
Measure total concentration
of oil in effluent
Verify infrared data
May not correspond directly
to soluble oil content
Measure water soluble
component of oil
Measure concentration of
soluble hydrocarbons in water
Determine physical charac-
teristics of oil in effluent
Detect surface active agents
that may interfere in oil/
water separation
Characterize oil
Characterize oil
Characterize brine
Characterize brine
Characterize brine
Estimate bacterial population
Estimate ease of separating
the oil and water
Characterize brine
Measure volume of effluent
Measure ratio of water to oil
in production stream
Characterize oil
SRI Recommendation/ Modification
Analyze with the Miran 1A -FF*. use
Freon 113 rather than Freon TF
No change, but question necessity
Drop test
Agitate sample and centrifuge
remove oil drops
Filter and analyze with Miran
1A-FF
Drop test
Conducted in laboratory
Use Brookfield viscometer
No change
No change
No change
Drop test
No change
Drop test
No change
Drop test
Drop test
Drop test
to
included in SFil field test kit.
+From Reference 3.
Table3. Comparison of Three Oil-in- Water Analyzers
Instrument
Feature
Weight (kg)
Wavelength (nmj
Solvent
ppm oil measured
directly on scale
Oil analysis (ppm)*
Average deviation
1.
2.
3.
4.
5.
6.
Horiba
8.9
3400-3500
CC/4 or Freon
0-100
592 ± 12
640 ± 12
656 ± 10
490 ± 40
562 ± 10
516 ± 10
± 16
Miran
6.5
3400-3500
CC/4 or Freon
0-3500
588 ±5
552 ±6
648 ±6
536 ±0
488 ±0
576 ± 10
±5
Turner
7.4
620 for No. 6 oil
340 for No. 2 oil
CHCIs
0-4000
656 ± 16
676 ±5
664 ±0
582 ±2
478 ±2
526 ± 14
±7
*0it-in-water samples from six different EPA dispersant effectiveness tests*
were analyzed on all three instruments. Each test was duplicated, and the
average and the deviation are reported.
transport easily. We therefore recom-
mend that the kit be simplified to focus
only on the oil-in-water analysis. Afield
test kit for measuring the oil content of
the platform effluent by the infrared
method would probably consist of one
suitcase (28-lb), the Miran spectrometer
(21 Ib), and the Freon solvent bottles (40
Ib). The onsite analysis time required to
conduct the single measurements
would also be shortened from about 8
labor-hours (to conduct all the tests) to
about 2 labor-hours.
References
1. "Study of Pollution Control Techn-
ology for Offshore Oil Drilling and
Production Platforms," Exxon Re-
search and Engineering, Linden,
New Jersey, EPA Contract No. 68-
03-2337 (February 1977).
2. Offshore Operators' Committee
Comments on: "Study of Pollution
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Table 4. Comparison of the Infrared and Gravimetric Oil Analysis Methods
Infrared Methods Gravimetric Methods
No. 6 Oil
Added
(mg)
41
32
38
Average
Std. Dev.
% Std. Dev.
No. 6 Oil
Recovered
(mgl
34
27
31
Recovery
%
82
85
80
82
3
4
No. 6 Oil
Added
(mg)
42*
41
32
38
No. 6 Oil
Recovered
(mg)
40
36
25
26
Recovery
(%)
95
87
78
68
78
10
13
*0il extracted from 500 ml of seawater with Freon 113 + 3 ml 12M HC1.
+0il dissolved directly in Freon 113.
Table 5. Solvent Extraction Efficiency for No. 6 Fuel Oil
Extractant*
CC1<
Average
Std. Dev.
% Std. Dev.
Freon 113
Average
Std. Dev.
% Std. Dev.
Freon 113}
Average
Std. Dev.
% Std. Dev.
Oil
Added (mg)
57
53
62
56
—
—
43
34
44
—
—
41
32
38
—
—
Oil
Recovered (mg)
54
52
59
54
I
—
31
29
25
—
—
34
27
31
I
—
% Recovery
95
98
95
96
96
1
1
72
85
57
71
14
20
83
84
82
83
1
1
*0il extracted from 500 ml seawater.
t+3 m!6M HC1
Control Technology for Offshore Oil
Drilling and Production Platforms,"
EPA Contract No. 68-03-2337 (June
1977).
3. "Field Verification of Pollution
Control Rationale for Offshore Oil
and Gas Production Platforms,"
Texas Instruments, Inc. Ecological
Services, Dallas, Texas, EPA Contract
No. 7-3-002-8 (May 30, 1979).
4. L.T. McCarthy, I. Wilder, and J. S.
Dorrler, "Standard EPA Dispersant
Effectiveness and Toxicity Tests,"
EPA-R2-73-201 (MayJ973).
The full report was submitted in
fulfillment of Grant No. R806091010 by
SRI International, Menlo Park, CA
94025, under the sponsorship of the
U.S. Environmental Protection Agency.
R. T. Rewick. J. Gates. K. A. Sabo. T.-W. Chou, and J. H. Smith are with SRI
International, Menlo Park, CA 94025.
Leo T. McCarthy is the EPA Project Officer (see below).
The complete report, entitled "Field Test Kit for Oil-Brine Effluents from Off-
shore Drilling Platforms," (Order No. PB 82-105 602; Cost: $6.50, subject to
change) will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Oil and Hazardous Materials Spills Branch
Municipal Environmental Research Laboratory—Cincinnati
U.S. Environmental Protection Agency
Edison, NJ 08837
U. S. GOVERNMENT PRINTING OFFICE: 1981/559-092/3343
-------
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