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. ------- 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 ------- 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 ------- United States Environmental Protection Agency Center for Environmental Research Information Cincinnati OH 45268 Postage and Fees Paid Environmental Protection Agency EPA 335 J Official Business Penalty for Private Use $300 RETURN POSTAGE GUARANTEED PS 0000329 US ENVIR PROTECTION AGFUCY HEGIUN 5 LIBRARY 230 S bEARBOPN 3TREE1 CHICAGO II. 60604 ------- |