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6.3 Equipment for sample extraction.
6.3.1 Vials—Glass, 25 mL and 4 mL, with Teflon-lined screw caps, baked at 200–250 °C for 1–h minimum prior to use.
6.3.2 Gas-tight syringes—Glass, various sizes, 0.5 mL to 2.5 mL (if spiking of drilling fluids with oils is to occur).
6.3.3 Auto pipetters—various sizes, 0.1 mL, 0.5 mL, 1 to 5 mL delivery, and 10 mL delivery, with appropriate size disposable pipette tips, calibrated to within ±0.5%.
6.3.4 Glass stirring rod.
6.3.5 Vortex mixer.
6.3.6 Disposable syringes—Plastic, 5 mL.
6.3.7 Teflon syringe filter, 25-mm, 0.45 µm pore size—Acrodisc® CR Teflon (or equivalent).
6.3.8 Reverse Phase Extraction C18 Cartridge—Waters Sep-Pak®Plus, C18 Cartridge, 360 mg of sorbent (or equivalent).
6.3.9 SPE vacuum manifold—Supelco Brand, 12 unit (or equivalent). Used as support for cartridge/syringe assembly only. Vacuum apparatus not required.
6.4 Equipment for fluorescence detection.
6.4.1 Black light—UV Lamp, Model UVG 11, Mineral Light Lamp, Shortwave 254 nm, or Longwave 365 nm, 15 volts, 60 Hz, 0.16 amps (or equivalent).
6.4.2 Black box—cartridge viewing area. A commercially available ultraviolet viewing cabinet with viewing lamp, or alternatively, a cardboard box or equivalent, approximately 14&inch;×7.5&inch;×7.5&inch; in size and painted flat black inside. Lamp positioned in fitted and sealed slot in center on top of box. Sample cartridges sit in a tray, ca. 6&inch; from lamp. Cardboard flaps cut on top panel and side of front panel for sample viewing and sample cartridge introduction, respectively.
6.4.3 Viewing platform for cartridges. Simple support (hand made vial tray—black in color) for cartridges so that they do not move during the fluorescence testing.
7.0 Reagents and Standards
7.1 Isopropyl alcohol—99% purity.
7.2 NAF—Appropriate NAF as sent from the supplier (has not been circulated downhole). Use the clean NAF corresponding to the NAF being used in the current drilling operation.
7.3 Standard crude oil—NIST SRM 1582 petroleum crude oil.
8.0 Sample Collection, Preservation, and Storage
8.1 Collect approximately one liter of representative sample (NAF, which has been circulated downhole) in a glass bottle or jar. Cover with a Teflon lined cap. To allow for a potential need to re-analyze and/or re-process the sample, it is recommended that a second sample aliquot be collected.
8.2 Label the sample appropriately.
8.3 All samples must be refrigerated at 0–4 °C from the time of collection until extraction (40 CFR Part 136, Table II).
8.4 All samples must be analyzed within 28 days of the date and time of collection (40 CFR Part 136, Table II).
9.0 Quality Control
9.1 Each laboratory that uses this method is required to operate a formal quality assurance program (Reference 16.3). The minimum requirements of this program consist of an initial demonstration of laboratory capability, and ongoing analyses of blanks and spiked duplicates to assess accuracy and precision and to demonstrate continued performance. Each field sample is analyzed in duplicate to demonstrate representativeness.
9.1.1 The analyst shall make an initial demonstration of the ability to generate acceptable accuracy and precision with this method. This ability is established as described in Section 9.2 of this appendix.
9.1.2 Preparation and analysis of a set of spiked duplicate samples to document accuracy and precision. The procedure for the preparation and analysis of these samples is described in Section 9.4 of this appendix.
9.1.3 Analyses of laboratory reagent blanks are required to demonstrate freedom from contamination. The procedure and criteria for preparation and analysis of a reagent blank are described in Section 9.5 of this appendix.
9.1.4 The laboratory shall maintain records to define the quality of the data that is generated.
9.1.5 Accompanying QC for the determination of oil in NAF is required per analytical batch. An analytical batch is a set of samples extracted at the same time, to a maximum of 10 samples. Each analytical batch of 10 or fewer samples must be accompanied by a laboratory reagent blank (Section 9.5 of this appendix), corresponding NAF reference blanks (Section 9.6 of this appendix), a set of spiked duplicate samples blank (Section 9.4 of this appendix), and duplicate analysis of each field sample. If greater than 10 samples are to be extracted at one time, the samples must be separated into analytical batches of 10 or fewer samples.
9.2 Initial demonstration of laboratory capability. To demonstrate the capability to perform the test, the analyst shall analyze two representative unused drilling fluids (e.g., internal olefin-based drilling fluid, vegetable ester-based drilling fluid), each prepared separately containing 0.1%, 1%, and 2% or a representative oil. Each drilling fluid/concentration combination shall be analyzed 10 times, and successful demonstration will yield the following average results for the data set:
0.1% oil—Detected in <20% of samples
1% oil—Detected in >75% of samples
2% oil—Detected in >90% of samples
9.3 Sample duplicates.
9.3.1 The laboratory shall prepare and analyze (Section 11.2 and 11.4 of this appendix) each authentic sample in duplicate, from a given sampling site or, if for compliance monitoring, from a given discharge.
9.3.2 The duplicate samples must be compared versus the prepared corresponding NAF blank.
9.3.3 Prepare and analyze the duplicate samples according to procedures outlined in Section 11 of this appendix.
9.3.4 The results of the duplicate analyses are acceptable if each of the results give the same response (fluorescence or no fluorescence). If the results are different, sample non-homogenicity issues may be a concern. Prepare the samples again, ensuring a well-mixed sample prior to extraction. Analyze the samples once again.
9.3.5 If different results are obtained for the duplicate a second time, the analytical system is judged to be out of control and the problem shall be identified and corrected, and the samples re-analyzed.
9.4 Spiked duplicates—Laboratory prepared spiked duplicates are analyzed to demonstrate acceptable accuracy and precision.
9.4.1 Preparation and analysis of a set of spiked duplicate samples with each set of no more than 10 field samples is required to demonstrate method accuracy and precision and to monitor matrix interferences (interferences caused by the sample matrix). A field NAF sample expected to contain less than 0.5% crude oil (and documented to not fluoresce as part of the sample batch analysis) shall be spiked with 1% (by volume) of suitable reference crude oil and analyzed as field samples, as described in Section 11 of this appendix. If no low-level drilling fluid is available, then the unused NAF can be used as the drilling fluid sample.
9.5 Laboratory reagent blanks—Laboratory reagent blanks are analyzed to demonstrate freedom from contamination.
9.5.1 A reagent blank is prepared by passing 4 mL of the isopropyl alcohol through a Teflon syringe filter and collecting the filtrate in a 4-mL glass vial. A Sep Pak® C18 cartridge is then preconditioned with 3 mL of isopropyl alcohol. A 0.5-mL aliquot of the filtered isopropyl alcohol is added to the syringe barrel along with 3.0 mL of isopropyl alcohol. The solvent is passed through the preconditioned Sep Pak® cartridge. An additional 2-mL of isopropyl alcohol is eluted through the cartridge. The cartridge is now considered the “reagent blank” cartridge and is ready for viewing (analysis). Check the reagent blank cartridge under the black light for fluorescence. If the isopropyl alcohol and filter are clean, no fluorescence will be observed.
9.5.2 If fluorescence is detected in the reagent blank cartridge, analysis of the samples is halted until the source of contamination is eliminated and a prepared reagent blank shows no fluorescence under a black light. All samples shall be associated with an uncontaminated method blank before the results may be reported for regulatory compliance purposes.
9.6 NAF reference blanks—NAF reference blanks are prepared from the NAFs sent from the supplier (NAF that has not been circulated downhole) and used as the reference when viewing the fluorescence of the test samples.
9.6.1 A NAF reference blank is prepared identically to the authentic samples. Place a 0.1 mL aliquot of the “clean” NAF into a 25-mL glass vial. Add 10 mL of isopropyl alcohol to the vial. Cap the vial. Vortex the vial for approximately 10 sec. Allow the solids to settle for approximately 15 minutes. Using a 5-mL syringe, draw up 4 mL of the extract and filter it through a PTFE syringe filter, collecting the filtrate in a 4-mL glass vial. Precondition a Sep Pak® C18 cartridge with 3 mL of isopropyl alcohol. Add a 0.5-mL aliquot of the filtered extract to the syringe barrel along with 3.0 mL of isopropyl alcohol. Pass the extract and solvent through the preconditioned Sep Pak® cartridge. Pass an additional 2-mL of isopropyl alcohol through the cartridge. The cartridge is now considered the NAF blank cartridge and is ready for viewing (analysis). This cartridge is used as the reference cartridge for determining the absence or presence of fluorescence in all authentic drilling fluid samples that originate from the same NAF. That is, the specific NAF reference blank cartridge is put under the black light along with a prepared cartridge of an authentic sample originating from the same NAF material. The fluorescence or absence of fluorescence in the authentic sample cartridge is determined relative to the NAF reference cartridge.
9.6.2 Positive control solution, equivalent to 1% crude oil contaminated mud extract, is prepared by dissolving 87 mg of standard crude oil into 10.00 mL of methylene chloride. Then mix 40 µL of this solution into 10.00 mL of IPA. Transfer 0.5 mL of this solution into a preconditioned C18 cartridge, followed by 2 ml of IPA.
10.0 Calibration and Standardization
10.1 Calibration and standardization methods are not employed for this procedure.
11.0 Procedure
This method is a screening-level test. Precise and accurate results can be obtained only by strict adherence to all details.
11.1 Preparation of the analytical batch.
11.1.1 Bring the analytical batch of samples to room temperature.
11.1.2 Using a large glass stirring rod, mix the authentic sample thoroughly.
11.1.3 Using a large glass stirring rod, mix the clean NAF (sent from the supplier) thoroughly.
11.2 Extraction.
11.2.1 Using an automatic positive displacement pipetter and a disposable pipette tip transfer 0.1-mL of the authentic sample into a 25-mL vial.
11.2.2 Using an automatic pipetter and a disposable pipette tip dispense a 10-mL aliquot of solvent grade isopropyl alcohol (IPA) into the 25 mL vial.
11.2.3 Cap the vial and vortex the vial for ca. 10–15 seconds.
11.2.4 Let the sample extract stand for approximately 5 minutes, allowing the solids to separate.
11.2.5 Using a 5-mL disposable plastic syringe remove 4 mL of the extract from the 25-mL vial.
11.2.6 Filter 4 mL of extract through a Teflon syringe filter (25-mm diameter, 0.45 µm pore size), collecting the filtrate in a labeled 4-mL vial.
11.2.7 Dispose of the PFTE syringe filter.
11.2.8 Using a black permanent marker, label a Sep Pak® C18 cartridge with the sample identification.
11.2.9 Place the labeled Sep Pak® C18 cartridge onto the head of a SPE vacuum manifold.
11.2.10 Using a 5-mL disposable plastic syringe, draw up exactly 3-mL (air free) of isopropyl alcohol.
11.2.11 Attach the syringe tip to the top of the C18 cartridge.
11.2.12 Condition the C18 cartridge with the 3-mL of isopropyl alcohol by depressing the plunger slowly.
Note: Depress the plunger just to the point when no liquid remains in the syringe barrel. Do not force air through the cartridge. Collect the eluate in a waste vial.
11.2.13 Remove the syringe temporarily from the top of the cartridge, then remove the plunger, and finally reattach the syringe barrel to the top of the C18 cartridge.
11.2.14 Using automatic pipetters and disposable pipette tips, transfer 0.5 mL of the filtered extract into the syringe barrel, followed by a 3.0-mL transfer of isopropyl alcohol to the syringe barrel.
11.2.15 Insert the plunger and slowly depress it to pass only the extract and solvent through the preconditioned C18 cartridge.
Note: Depress the plunger just to the point when no liquid remains in the syringe barrel. Do not force air through the cartridge. Collect the eluate in a waste vial.
11.2.16 Remove the syringe temporarily from the top of the cartridge, then remove the plunger, and finally reattach the syringe barrel to the top of the C18 cartridge.
11.2.17 Using an automatic pipetter and disposable pipette tip, transfer 2.0 mL of isopropyl alcohol to the syringe barrel.
11.2.18 Insert the plunger and slowly depress it to pass the solvent through the C18 cartridge.
Note: Depress the plunger just to the point when no liquid remains in the syringe barrel. Do not force air through the cartridge. Collect the eluate in a waste vial.
11.2.19 Remove the syringe and labeled C18 cartridge from the top of the SPE vacuum manifold.
11.2.20 Prepare a reagent blank according to the procedures outlined in Section 9.5 of this appendix.
11.2.21 Prepare the necessary NAF reference blanks for each type of NAF encountered in the field samples according to the procedures outlined in Section 9.6 of this appendix.
11.2.22 Prepare the positive control (1% crude oil equivalent) according to Section 9.6.2 of this appendix.
11.3 Reagent blank fluorescence testing.
11.3.1 Place the reagent blank cartridge in a black box, under a black light.
11.3.2 Determine the presence or absence of fluorescence for the reagent blank cartridge. If fluorescence is detected in the blank, analysis of the samples is halted until the source of contamination is eliminated and a prepared reagent blank shows no fluorescence under a black light. All samples must be associated with an uncontaminated method blank before the results may be reported for regulatory compliance purposes.
11.4 Sample fluorescence testing.
11.4.1 Place the respective NAF reference blank (Section 9.6 of this appendix) onto the tray inside the black box.
11.4.2 Place the authentic field sample cartridge (derived from the same NAF as the NAF reference blank) onto the tray, adjacent and to the right of the NAF reference blank.
11.4.3 Turn on the black light.
11.4.4 Compare the fluorescence of the sample cartridge with that of the negative control cartridge (NAF blank, Section 9.6.1 of this appendix) and positive control cartridge (1% crude oil equivalent, Section 9.6.2 of this appendix).
11.4.5 If the fluorescence of the sample cartridge is equal to or brighter than the positive control cartridge (1% crude oil equivalent, Section 9.6.2 of this appendix), the sample is considered contaminated. Otherwise, the sample is clean.
12.0 Data Analysis and Calculations
Specific data analysis techniques and calculations are not performed in this SOP.
13.0 Method Performance
This method was validated through a single laboratory study, conducted with rigorous statistical experimental design and interpretation (Reference 16.4).
14.0 Pollution Prevention
14.1 The solvent used in this method poses little threat to the environment when recycled and managed properly.
15.0 Waste Management
15.1 It is the laboratory's responsibility to comply with all Federal, State, and local regulations governing waste management, particularly the hazardous waste identification rules and land disposal restriction, and to protect the air, water, and land by minimizing and controlling all releases from bench operations. Compliance with all sewage discharge permits and regulations is also required.
15.2 All authentic samples (drilling fluids) failing the fluorescence test (indicated by the presence of fluorescence) shall be retained and classified as contaminated samples. Treatment and ultimate fate of these samples is not outlined in this SOP.
15.3 For further information on waste management, consult “The Waste Management Manual for Laboratory Personnel,” and “Less is Better: Laboratory Chemical Management for Waste Reduction,” both available from the American Chemical Society's Department of Government Relations and Science Policy, 1155 16th Street, NW, Washington, DC 20036.
16.0 References
16.1 “Carcinogen—Working with Carcinogens,” Department of Health, Education, and Welfare, Public Health Service, Center for Disease Control, National Institute for Occupational Safety and Health, Publication No. 77–206, August 1977.
16.2 “OSHA Safety and Health Standards, General Industry,” (29 CFR 1910), Occupational Safety and Health Administration, OSHA 2206 (Revised, January 1976).
16.3 “Handbook of Analytical Quality Control in Water and Wastewater Laboratories,” USEPA, EMSL-Ci, Cincinnati, OH 45268, EPA–600/4–79–019, March 1979.
16.4 Report of the Laboratory Evaluation of Static Sheen Test Replacements—Reverse Phase Extraction (RPE) Method for Detecting Oil Contamination in Synthetic Based Mud (SBM). October 1998. Available from API, 1220 L Street, NW, Washington, DC 20005–4070, 202–682–8000.
[66 FR 6901, Jan. 22, 2001; 66 FR 30811, June 8, 2001]
Appendix 7 to Subpart A of Part 435—API Recommended Practice 13B–2
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1. Description
a. This procedure is specifically intended to measure the amount of non-aqueous drilling fluid (NAF) base fluid from cuttings generated during a drilling operation. This procedure is a retort test which measures all oily material (NAF base fluid) and water released from a cuttings sample when heated in a calibrated and properly operating “Retort” instrument.
b. In this retort test a known mass of cuttings is heated in the retort chamber to vaporize the liquids associated with the sample. The NAF base fluid and water vapors are then condensed, collected, and measured in a precision graduated receiver.
Note: Obtaining a representative sample requires special attention to the details of sample handling (e.g., location, method, frequency). See Addendum A and B for minimum requirements for collecting representative samples. Additional sampling procedures in a given area may be specified by the NPDES permit controlling authority.
2. Equipment
a. Retort instrument—The recommended retort instrument has a 50-cm 3 volume with an external heating jacket.
Retort Specifications:
1. Retort assembly—retort body, cup and lid.
(a) Material: 303 stainless steel or equivalent.
(b) Volume: Retort cup with lid.
Cup Volume: 50-cm 3 .
Precision: ±0.25-cm 3 .
2. Condenser—capable of cooling the oil and water vapors below their liquification temperature.
3. Heating jacket—nominal 350 watts.
4. Temperature control—capable of limiting temperature of retort to at least 930 °F (500 °C) and enough to boil off all NAFs.
b. Liquid receiver (10-cm 3 , 20-cm 3 )—the 10-cm 3 and 20-cm 3 receivers are specially designed cylindrical glassware with rounded bottom to facilitate cleaning and funnel-shaped top to catch falling drops. For compliance monitoring under the NPDES program, the analyst shall use the 10-cm 3 liquid receiver with 0.1 ml graduations to achieve greater accuracy.
1. Receiver specifications:
Total volume: 10-cm 3 , 20-cm 3 .
Precision (0 to 100%): ±0.05 cm 3 , ±0.05 cm 3 .
Outside diameter: 10-mm, 13-mm.
Wall thickness: 1.5 ±0.1mm, 1.2 ±0.1mm.
Frequency of graduation marks (0 to 100%): 0.10-cm 3 , 0.10-cm 3 .
Calibration: To contain “TC” @ 20 °C.
Scale: cm 3 , cm 3
2. Material—Pyrex® or equivalent glass.
c. Toploading balance—capable of weighing 2000 g and precision of at least 0.1 g. Unless motion is a problem, the analyst shall use an electronic balance. Where motion is a problem, the analyst may use a triple beam balance.
d. Fine steel wool (No. 000)—for packing retort body.
e. Thread sealant lubricant: high temperature lubricant, e.g. Never-Seez® or equivalent.
f. Pipe cleaners—to clean condenser and retort stem.
g. Brush—to clean receivers.
h. Retort spatula—to clean retort cup.
i. Corkscrew—to remove spent steel wool.
3. Procedure
a. Clean and dry the retort assembly and condenser.
b. Pack the retort body with steel wool.
c. Apply lubricant/sealant to threads of retort cup and retort stem.
d. Weigh and record the total mass of the retort cup, lid, and retort body with steel wool. This is mass (A), grams.
e. Collect a representative cuttings sample (see Note in Section 1 of this appendix).
f. Partially fill the retort cup with cuttings and place the lid on the cup.
g. Screw the retort cup (with lid) onto the retort body, weigh and record the total mass. This is mass (B), grams.
h. Attach the condenser. Place the retort assembly into the heating jacket.
i. Weigh and record the mass of the clean and dry liquid receiver. This is mass (C), grams. Place the receiver below condenser outlet.
j. Turn on the retort. Allow it to run a minimum of 1 hour.
Note: If solids boil over into receiver, the test shall be rerun. Pack the retort body with a greater amount of steel wool and repeat the test.
k. Remove the liquid receiver. Allow it to cool. Record the volume of water recovered. This is (V), cm 3 .
Note: If an emulsion interface is present between the oil and water phases, heating the interface may break the emulsion. As a suggestion, remove the retort assembly from the heating jacket by grasping the condenser. Carefully heat the receiver along the emulsion band by gently touching the receiver for short intervals with the hot retort assembly. Avoid boiling the liquids. After the emulsion interface is broken, allow the liquid receiver to cool. Read the water volume at the lowest point of the meniscus.
l. Weigh and record the mass of the receiver and its liquid contents (oil plus water). This is mass (D), grams.
m. Turn off the retort. Remove the retort assembly and condenser from the heating jacket and allow them to cool. Remove the condenser.
n. Weigh and record the mass of the cooled retort assembly without the condenser. This is mass (E), grams.
o. Clean the retort assembly and condenser.
4. Calculations
a. Calculate the mass of oil (NAF base fluid) from the cuttings as follows:
1. Mass of the wet cuttings sample (Mw) equals the mass of the retort assembly with the wet cuttings sample (B) minus the mass of the empty retort assembly (A).
Mw = B-A [1]
2. Mass of the dry retorted cuttings (MD) equals the mass of the cooled retort assembly (E) minus the mass of the empty retort assembly (A).
MD = E-A [2]
3. Mass of the NAF base fluid (MBF) equals the mass of the liquid receiver with its contents (D) minus the sum of the mass of the dry receiver (C) and the mass of the water (V).
MBF = D-(C + V) [3]
Note: Assuming the density of water is 1 g/cm 3 , the volume of water is equivalent to the mass of the water.
b. Mass balance requirement:
The sum of MD, MBF, and V shall be within 5% of the mass of the wet sample.
(MD + MBF + V)/Mw = 0.95 to 1.05 [4]
The procedure shall be repeated if this requirement is not met.
c. Reporting oil from cuttings:
1. Assume that all oil recovered is NAF base fluid.
2. The mass percent NAF base fluid retained on the cuttings (%BFi) for the sampled discharge “i” is equal to 100 times the mass of the NAF base fluid (MBF) divided by the mass of the wet cuttings sample (Mw).
%BFi = (MBF/Mw) × 100 [5]
Operators discharging small volume NAF-cuttings discharges which do not occur during a NAF-cuttings discharge sampling interval (i.e., displaced interfaces, accumulated solids in sand traps, pit clean-out solids, or centrifuge discharges while cutting mud weight) shall either: (a) Measure the mass percent NAF base fluid retained on the cuttings (%BFSVD) for each small volume NAF-cuttings discharges; or (b) use a default value of 25% NAF base fluid retained on the cuttings.
3. The mass percent NAF base fluid retained on the cuttings is determined for all cuttings wastestreams and includes fines discharges and any accumulated solids discharged [see Section 4.c.6 of this appendix for procedures on measuring or estimating the mass percent NAF base fluid retained on the cuttings (%BF) for dual gradient drilling seafloor discharges performed to ensure proper operation of subsea pumps].
4. A mass NAF-cuttings discharge fraction (X, unitless) is calculated for all NAF-cuttings, fines, or accumulated solids discharges every time a set of retorts is performed (see Section 4.c.6 of this appendix for procedures on measuring or estimating the mass NAF-cuttings discharge fraction (X) for dual gradient drilling seafloor discharges performed to ensure proper operation of subsea pumps). The mass NAF-cuttings discharge fraction (X) combines the mass of NAF-cuttings, fines, or accumulated solids discharged from a particular discharge over a set period of time with the total mass of NAF-cuttings, fines, or accumulated solids discharged into the ocean during the same period of time (see Addendum A and B of this appendix). The mass NAF-cuttings discharge fraction (X) for each discharge is calculated by direct measurement as:
Xi = (Fi)/(G) [6]
where:
Xi = Mass NAF-cuttings discharge fraction for NAF-cuttings, fines, or accumulated solids discharge “i”, (unitless)
Fi = Mass of NAF-cuttings discharged from NAF-cuttings, fines, or accumulated solids discharge “i” over a specified period of time (see Addendum A and B of this appendix), (kg)
G = Mass of all NAF-cuttings discharges into the ocean during the same period of time as used to calculate Fi, (kg)
If an operator has more than one point of NAF-cuttings discharge, the mass faction (Xi) must be determined by: (a) Direct measurement (see Equation 6 of this Appendix); (b) using the following default values of 0.85 and 0.15 for the cuttings dryer (e.g., horizontal centrifuge, vertical centrifuge, squeeze press, High-G linear shakers) and fines removal unit (e.g., decanting centrifuges, mud cleaners), respectively, when the operator is only discharging from the cuttings dryer and the fines removal unit; or (c) using direct measurement of “Fi” (see Equation 6 of this Appendix) for fines and accumulated solids, using Equation 6A of this Appendix to calculate “GEST” for use as “G” in Equation 6 of this Appendix, and calculating the mass (kg) of NAF-cuttings discharged from the cuttings dryer (Fi) as the difference between the mass of “GEST” calculated in Equation 6A of this appendix (kg) and the sum of all fines and accumulated solids mass directly measured (kg) (see Equation 6 of this Appendix).
GEST = Estimated mass of all NAF-cuttings discharges into the ocean during the same period of time as used to calculate Fi (see Equation 6 of this Appendix), (kg) [6A]
where:
GEST = Hole Volume (bbl) × (396.9 kg/bbl) × (1 + Z/100)
Z = The base fluid retained on cuttings limitation or standard (%) which apply to the NAF being discharge (see §§435.13. and 435.15).
Hole Volume (bbl) = [Cross-Section Area of NAF interval (in 2 )] × Average Rate of Penetration (feet/hr) × period of time (min) used to calculate Fi (see Equation 6 of this Appendix) × (1 hr/60 min) × (1 bbl/5.61 ft 3 ) × (1 ft/12 in) 2
Cross-Section Area of NAF interval (in 2 ) = (3.14 × [Bit Diameter (in)] 2 )/4
Bit Diameter (in) = Diameter of drilling bit for the NAF interval producing drilling cuttings during the same period of time as used to calculate Fi (see Equation 6 of this Appendix)
Average Rate of Penetration (feet/hr) = Arithmetic average of rate of penetration into the formation during the same period of time as used to calculate Fi (see Equation 6 of this Appendix)
Note: Operators with one NAF-cuttings discharge may set the mass NAF-cuttings discharge fraction (Xi) equal to 1.0.
5. Each NAF-cuttings, fines, or accumulated solids discharge has an associated mass percent NAF base fluid retained on cuttings value (%BF) and mass NAF-cuttings discharge fraction (X) each time a set of retorts is performed. A single total mass percent NAF base fluid retained on cuttings value (%BFT) is calculated every time a set of retorts is performed. The single total mass percent NAF base fluid retained on cuttings value (%BFT) is calculated as:
%BFT,j = S(Xi)×(%BFi) [7]
where:
%BFT,j = Total mass percent NAF base fluid retained on cuttings value for retort set “j” (unitless as percentage, %)
Xi = Mass NAF-cuttings discharge fraction for NAF-cuttings, fines, or accumulated solids discharge “i”, (unitless)
%BFi = Mass percent NAF base fluid retained on the cuttings for NAF-cuttings, fines, or accumulated solids discharge “i” , (unitless as percentage, %)
Note: SXi = 1.
Operators with one NAF-cuttings discharge may set %BFT,j equal to %BFi.
6. Operators performing dual gradient drilling operations may require seafloor discharges of large cuttings (> 1/4') to ensure the proper operation of subsea pumps (e.g., electrical submersible pumps). Operators performing dual gradient drilling operations which lead to seafloor discharges of large cuttings for the proper operation of subsea pumps shall either: (a) Measure the mass percent NAF base fluid retained on cuttings value (%BF) and mass NAF-cuttings discharge fraction (X) for seafloor discharges each time a set of retorts is performed; (b) use the following set of default values, (%BF=14%; X=0.15); or (c) use a combination of (a) and (b) (e.g., use a default value for %BF and measure X).
Additionally, operators performing dual gradient drilling operations which lead to seafloor discharges of large cuttings for the proper operation of subsea pumps shall also perform the following tasks:
(a) Use side scan sonar or shallow seismic to determine the presence of high density chemosynthetic communities. Chemosynthetic communities are assemblages of tube worms, clams, mussels, and bacterial mats that occur at natural hydrocarbon seeps or vents, generally in water depths of 500 meters or deeper. Seafloor discharges of large cuttings for the proper operation of subsea pumps shall not be permitted within 1000 feet of a high density chemosynthetic community.
(b) Seafloor discharges of large cuttings for the proper operation of subsea pumps shall be visually monitored and documented by a Remotely Operated Vehicle (ROV) within the tether limit (approximately 300 feet). The visual monitoring shall be conducted prior to each time the discharge point is relocated (cuttings discharge hose) and conducted along the same direction as the discharge hose position. Near-seabed currents shall be obtained at the time of the visual monitoring.
(c) Seafloor discharges of large cuttings for the proper operation of subsea pumps shall be directed within a 150 foot radius of the wellbore.
7. The weighted mass ratio averaged over all NAF well sections (%BFwell) is the compliance value that is compared with the “maximum weighted mass ratio averaged over all NAF well sections” BAT discharge limitations (see the table in §435.13 and footnote 5 of the table in §435.43) or the “maximum weighted mass ratio averaged over all NAF well sections” NSPS discharge limitations (see the table in §435.15 and footnote 5 of the table in §435.45). The weighted mass ratio averaged over all NAF well sections (%BFwell) is calculated as the arithmetic average of all total mass percent NAF base fluid retained on cuttings values (%BFT) and is given by the following expression:
%BFwell = [j=1 to j=n S (%BFT,j)]/n [8]
where:
%BFwell = Weighted mass ratio averaged over all NAF well sections (unitless as percentage, %)
%BFT,j = Total mass percent NAF base fluid retained on cuttings value for retort set “j” (unitless as percentage, %)
n = Total number of retort sets performed over all NAF well sections (unitless)
Small volume NAF-cuttings discharges which do not occur during a NAF-cuttings discharge sampling interval (i.e., displaced interfaces, accumulated solids in sand traps, pit clean-out solids, or centrifuge discharges while cutting mud weight) shall be mass averaged with the arithmetic average of all total mass percent NAF base fluid retained on cuttings values (see Equation 8 of this Appendix). An additional sampling interval shall be added to the calculation of the weighted mass ratio averaged over all NAF well sections (%BFwell). The mass fraction of the small volume NAF-cuttings discharges (XSVD) will be determined by dividing the mass of the small volume NAF-cuttings discharges (FSVD) by the total mass of NAF-cuttings discharges for the well drilling operation (GWELL + FSVD).
XSVD = FSVD / (GWELL + FSVD) [9]
where:
XSVD = mass fraction of the small volume NAF-cuttings discharges (unitless)
FSVD = mass of the small volume NAF-cuttings discharges (kg)
GWELL = mass of total NAF-cuttings from the well (kg)
The mass of small volume NAF-cuttings discharges (FSVD) shall be determined by multiplying the density of the small volume NAF-cuttings discharges (?svd) times the volume of the small volume NAF-cuttings discharges (VSVD).
FSVD = ?svd × VSVD [10]
where:
FSVD = mass of small volume NAF-cuttings discharges (kg)
?svd = density of the small volume NAF-cuttings discharges (kg/bbl)
VSVD = volume of the small volume NAF-cuttings discharges (bbl)
The density of the small volume NAF-cuttings discharges shall be measured. The volume of small volume discharges (VSVD) shall be either: (a) Be measured or (b) use default values of 10 bbl of SBF for each interface loss and 75 bbl of SBM for pit cleanout per well.
The total mass of NAF-cuttings discharges for the well (GWELL) shall be either: (a) Measured; or (b) calculated by multiplying 1.0 plus the arithmetic average of all total mass percent NAF base fluid retained on cuttings values [see Equation 8 of this Appendix] times the total hole volume (VWELL) for all NAF well sections times a default value for the density the formation of 2.5 g/cm 3 (396.9 kg/bbl).
where:
GWELL = total mass of NAF-cuttings discharges for the well (kg)
[j = 1 to j = n S(%BFT,j)]/n = see Equation 8 of this Appendix (unitless as a percentage)
VWELL = total hole volume (VWELL) for all NAF well sections (bbl)
The total hole volume of NAF well sections (VWELL) will be calculated as:
For wells where small volume discharges associated with cuttings are made, %BFWELL becomes:
Note: See Addendum A and B to determine the sampling frequency to determine the total number of retort sets required for all NAF well sections.
8. The total number of retort sets (n) is increased by 1 for each sampling interval (see Section 2.4, Addendum A of this appendix) when all NAF cuttings, fines, or accumulated solids for that sampling interval are retained for no discharge. A zero discharge interval shall be at least 500 feet up to a maximum of three per day. This action has the effect of setting the total mass percent NAF base fluid retained on cuttings value (%BFT) at zero for that NAF sampling interval when all NAF cuttings, fines, or accumulated solids are retained for no discharge.
9. Operators that elect to use the Best Management Practices (BMPs) for NAF-cuttings shall use the procedures outlined in Addendum B.
Addendum A to Appendix 7 to Subpart A of Part 435—Sampling of Cuttings Discharge Streams for use with API Recommended Practice 13B–2
1.0 Sampling Locations
1.1 Each NAF-cuttings waste stream that discharges into the ocean shall be sampled and analyzed as detailed in Appendix 7. NAF-cuttings discharges to the ocean may include discharges from primary shakers, secondary shakers, cuttings dryer, fines removal unit, accumulated solids, and any other cuttings separation device whose NAF-cuttings waste is discharged to the ocean. NAF-cuttings wastestreams not directly discharged to the ocean (e.g., NAF-cuttings generated from shake shakers and sent to a cuttings dryer for additional processing) do not require sampling and analysis.
1.2 The collected samples shall be representative of each NAF-cuttings discharge. Operators shall conduct sampling to avoid the serious consequences of error (i.e., bias or inaccuracy). Operators shall collect NAF-cuttings samples near the point of origin and before the solids and liquid fractions of the stream have a chance to separate from one another. For example, operators shall collect shale shaker NAF-cuttings samples at the point where NAF-cuttings are coming off the shale shaker and not from a holding container downstream where separation of larger particles from the liquid can take place.
1.3 Operators shall provide a simple schematic diagram of the solids control system and sample locations to the NPDES permit controlling authority.
2.0 Type of Sample and Sampling Frequency
2.1 Each NAF-cuttings, fines, or accumulated solids discharge has an associated mass percent NAF base fluid retained on cuttings value (%BF) and mass NAF-cuttings discharge fraction (X) for each sampling interval (see Section 2.4 of this addendum). Operators shall collect a single discrete NAF-cuttings sample for each NAF-cuttings waste stream discharged to the ocean during every sampling interval.
2.2 Operators shall use measured depth in feet from the Kelly bushing when samples are collected.
2.3 The NAF-cuttings samples collected for the mass fraction analysis (see Equation 6, Appendix 7 of Subpart A of this part) shall also be used for the retort analysis (see Equations 1–5, Appendix 7 of Subpart A of this part).
2.4 Operators shall collect and analyze at least one set of NAF-cuttings samples per day while discharging. Operators engaged in fast drilling (i.e., greater than 500 linear NAF feet advancement of drill bit per day) shall collect and analyze one set of NAF-cuttings samples per 500 linear NAF feet of footage drilled. Operators are not required to collect and analyze more than three sets of NAF-cuttings samples per day (i.e., three sampling intervals). Operators performing zero discharge of all NAF-cuttings (i.e., all NAF cuttings, fines, or accumulated solids retained for no discharge) shall use the following periods to count sampling intervals: (1) One sampling interval per day when drilling is less than 500 linear NAF feet advancement of drill bit per day; and (2) one sampling interval per 500 linear NAF feet of footage drilled with a maximum of three sampling intervals per day.
2.5 The operator shall measure the individual masses (Fi, kg) and sum total mass (G, kg) (see Equation 6, Appendix 7 of subpart A of this part) over a representative period of time (e.g., <10 minutes) during steady-state conditions for each sampling interval (see Section 2.4 of this addendum). The operator shall ensure that all NAF-cuttings are capture for mass analysis during the same sampling time period (e.g., <10 minutes) at approximately the same time (i.e., all individual mass samples collected within one hour of each other).
2.6 Operators using Best Management Practices (BMPs) to control NAF-cuttings discharges shall follow the procedures in Addendum B to Appendix 7 of subpart A of 40 CFR 435.
3.0 Sample Size and Handling
3.1 The volume of each sample depends on the volumetric flow rate (cm 3 /s) of the NAF-cuttings stream and the sampling time period (e.g., <10 minutes). Consequently, different solids control equipment units producing different NAF-cuttings waste streams at different volumetric flow rates will produce different size samples for the same period of time. Operators shall use appropriately sized sample containers for each NAF-cuttings waste stream to ensure no NAF-cuttings are spilled during sample collection. Operators shall use the same time period (e.g., <10 minutes) to collect NAF-cuttings samples from each NAF-cuttings waste stream. Each NAF-cuttings sample size shall be at least one gallon. Operators shall clearly mark each container to identify each NAF-cuttings sample.
3.2 Operators shall not decant, heat, wash, or towel the NAF-cuttings to remove NAF base fluid before mass and retort analysis.
3.3 Operators shall first calculate the mass of each NAF-cuttings sample and perform the mass ratio analysis (see Equation 6, Appendix 7 of subpart A of this part). Operators with only one NAF-cuttings discharge may skip this step (see Section 4.c.4, Appendix 7 of subpart A of this part).
3.4 Operators shall homogenize (e.g., stirring, shaking) each NAF-cuttings sample prior to placing a sub-sample into the retort cup. The bottom of the NAF-cuttings sample container shall be examined to be sure that solids are not sticking to it.
3.5 Operators shall then calculate the NAF base fluid retained on cuttings using the retort procedure (see Equations 1–5, Appendix 7 of subpart A of this part). Operators shall start the retort analyses no more than two hours after collecting the first individual mass sample for the sampling interval .
3.6 Operators shall not discharge any sample before successfully completing the mass and retort analyses [i.e., mass balance requirements (see Section 4.b, Appendix 7 of subpart A of this part) are satisfied]. Operators shall immediately re-run the retort analyses if the mass balance requirements (see Equation 4, Appendix 7 of subpart A of this part) are not within a tolerance of 5% (see Section 4.b, Equation 4, Appendix 7 of subpart A of this part).
4.0 Calculations
4.1 Operators shall calculate a set of mass percent NAF base fluid retained on cuttings values (%BF) and mass NAF-cuttings discharge fractions (X) for each NAF-cuttings waste stream (see Section 1.1 of this addendum) for each sampling interval (see Section 2.4 of this addendum) using the procedures outlined in Appendix 7 of subpart A of this part.
4.2 Operators shall tabulate the following data for each individual NAF-cuttings sample: (1) Date and time of NAF-cuttings sample collection; (2) time period of NAF-cuttings sample collection (see Section 3.1 of this addendum); (3) mass and volume of each NAF-cuttings sample; (4) measured depth (feet) at NAF-cuttings sample collection (see Section 2.2 of this addendum); (5) respective linear feet of hole drilled represented by the NAF-cuttings sample (feet); and (6) the drill bit diameter (inches) used to generate the NAF-cuttings sample cuttings.
4.3 Operators shall calculate a single total mass percent NAF base fluid retained on cuttings value (%BFT) for each sampling interval (see Section 2.4 of this addendum) using the procedures outlined in Appendix 7 of Subpart A of this part.
4.4 Operators shall tabulate the following data for each total mass percent NAF base fluid retained on cuttings value (%BFT) for each NAF-cuttings sampling interval: (1) Date and starting and stopping times of NAF-cuttings sample collection and retort analyses; (2) measured depth of well (feet) at start of NAF-cuttings sample collection (see Section 2.2 of this addendum); (3) respective linear feet of hole drilled represented by the NAF-cuttings sample (feet); (4) the drill bit diameter (inches) used to generate the NAF-cuttings sample cuttings; and (5) annotation when zero discharge of NAF-cuttings is performed.
4.5 Operators shall calculate the weighted mass ratio averaged over all NAF well sections (%BFwell) using the procedures outlined in Appendix 7 of Subpart A of this part.
4.6 Operators shall tabulate the following data for each weighted mass ratio averaged over all NAF well sections (%BFwell) for each NAF well: (1) Starting and stopping dates of NAF well sections; (2) measured depth (feet) of all NAF well sections; (3) total number of sampling intervals (see Section 2.4 and Section 2.6 of this addendum); (4) number of sampling intervals tabulated during any zero discharge operations; (5) total volume of zero discharged NAF-cuttings over entire NAF well sections; and (6) identification of whether BMPs were employed (see Addendum B of Appendix 7 of subpart A of this part).
Addendum B to Appendix 7 to Subpart A of Part 435—Best Management Practices (BMPs) for use with API Recommended Practice 13B–2
1.0 Overview of BMPs
1.1 Best Management Practices (BMPs) are inherently pollution prevention practices. BMPs may include the universe of pollution prevention encompassing production modifications, operational changes, material substitution, materials and water conservation, and other such measures. BMPs include methods to prevent toxic and hazardous pollutants from reaching receiving waters. Because BMPs are most effective when organized into a comprehensive facility BMP Plan, operators shall develop a BMP in accordance with the requirements in this addendum.
1.2 The BMP requirements contained in this appendix were compiled from several Regional permits, an EPA guidance document (i.e., Guidance Document for Developing Best Management Practices (BMP)” (EPA 833–B–93–004, U.S. EPA, 1993)), and draft industry BMPs. These common elements represent the appropriate mix of broad directions needed to complete a BMP Plan along with specific tasks common to all drilling operations.
1.3 Operators are not required to use BMPs if all NAF-cuttings discharges are monitored in accordance with Appendix 7 of Subpart A of this part.
2.0 BMP Plan Purpose and Objectives
2.1 Operators shall design the BMP Plan to prevent or minimize the generation and the potential for the discharge of NAF from the facility to the waters of the United States through normal operations and ancillary activities. The operator shall establish specific objectives for the control of NAF by conducting the following evaluations.
2.2 The operator shall identify and document each NAF well that uses BMPs before starting drilling operations and the anticipated total feet to be drilled with NAF for that particular well.
2.3 Each facility component or system controlled through use of BMPs shall be examined for its NAF-waste minimization opportunities and its potential for causing a discharge of NAF to waters of the United States due to equipment failure, improper operation, natural phenomena (e.g., rain, snowfall).
2.4 For each NAF wastestream controlled through BMPs where experience indicates a reasonable potential for equipment failure (e.g., a tank overflow or leakage), natural condition (e.g., precipitation), or other circumstances to result in NAF reaching surface waters, the BMP Plan shall include a prediction of the total quantity of NAF which could be discharged from the facility as a result of each condition or circumstance.
3.0 BMP Plan Requirements
3.1 The BMP Plan may reflect requirements within the pollution prevention requirements required by the Minerals Management Service (see 30 CFR 250.300) or other Federal or State requirements and incorporate any part of such plans into the BMP Plan by reference.
3.2 The operator shall certify that its BMP Plan is complete, on-site, and available upon request to EPA or the NPDES Permit controlling authority. This certification shall identify the NPDES permit number and be signed by an authorized representative of the operator. This certification shall be kept with the BMP Plan. For new or modified NPDES permits, the certification shall be made no later than the effective date of the new or modified permit. For existing NPDES permits, the certification shall be made within one year of permit issuance.
3.3 The BMP Plan shall:
3.3.1 Be documented in narrative form, and shall include any necessary plot plans, drawings or maps, and shall be developed in accordance with good engineering practices. At a minimum, the BMP Plan shall contain the planning, development and implementation, and evaluation/reevaluation components. Examples of these components are contained in “Guidance Document for Developing Best Management Practices (BMP)” (EPA 833–B–93–004, U.S. EPA, 1993).
3.3.2 Include the following provisions concerning BMP Plan review.
3.3.2.1 Be reviewed by permittee's drilling engineer and offshore installation manager (OIM) to ensure compliance with the BMP Plan purpose and objectives set forth in Section 2.0.
3.3.2.2 Include a statement that the review has been completed and that the BMP Plan fulfills the BMP Plan purpose and objectives set forth in Section 2.0. This statement shall have dated signatures from the permittee's drilling engineer and offshore installation manager and any other individuals responsible for development and implementation of the BMP Plan.
3.4 Address each component or system capable of generating or causing a release of significant amounts of NAF and identify specific preventative or remedial measures to be implemented.
4.0 BMP Plan Documentation
4.1 The operator shall maintain a copy of the BMP Plan and related documentation (e.g., training certifications, summary of the monitoring results, records of NAF-equipment spills, repairs, and maintenance) at the facility and shall make the BMP Plan and related documentation available to EPA or the NPDES Permit controlling authority upon request.
5.0 BMP Plan Modification
5.1 For those NAF wastestreams controlled through BMPs, the operator shall amend the BMP Plan whenever there is a change in the facility or in the operation of the facility which materially increases the generation of those NAF-wastes or their release or potential release to the receiving waters.
5.2 At a minimum the BMP Plan shall be reviewed once every five years and amended within three months if warranted. Any such changes to the BMP Plan shall be consistent with the objectives and specific requirements listed in this addendum. All changesin the BMP Plan shall be reviewed by the permittee's drilling engineer and offshore installation manager. (continued)