310 – Oil Production Sumps & Well Cellars

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# 2007 Area Source Emissions Inventory Methodology

310 – OIL PRODUCTION FUGITIVE LOSSES

I. Purpose
This document describes the Area Source Methodology used to estimate fugitive emissions of volatile organic compounds (VOCs) from oil sumps and well cellars in the San Joaquin Valley Air Basin. An area source c ategory is a collection of similar emission units within a geographic area (i.e., a Co unty). An area source category collectively represents individual sources that are small and numerous, and that may not have been inventoried as specific point, mobile , or biogenic sources. The California Air Resources Board (CARB) has grouped t hese individual sources with other like sources into area source categories. The se source categories are grouped in such a way that they can be estimated collective ly using one methodology.


## II. Applicability

The emission calculations from this Area Source Met hodology apply to facilities that are identified by the following Category of Emissio n Source (CES) codes and Reconciliation Emission Inventory Codes (REIC):

Table 1. Emission inventory codes. CES REIC Description 81950 310-300-1600-0000 Oil Production Fugitive Los ses – Sumps and Pits 82016 310-312-1600-0000 Oil Production Fugitive Los ses – Well Cellars



## III. Point Source Reconciliation
Emissions from the area source inventory and point source inventory are reconciled against each other to prevent double counting. Thi s is done using relationships created by the California Air Resources Board (ARB) between the area source REIC and the point sources’ Standard Industry Classifica tion (SIC) code and emissions process Source Category Code (SCC) combinations. T he area sources in this methodology are not represented within our point so urce inventory; therefore, reconciliation is not necessary. 

# San Joaquin Valley
AIR POLLUTION CONTROL DISTRICT310 – Oil Production Sumps & Well Cellars

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## IV. Methodology Description

SUMPS:
After petroleum is pumped from the ground, the crud e oil must be separated from the water, sand and other fluids present. In most cases, this process occurs in tanks or a combination of tanks and sumps. A sump is defined as an excavated lined or unlined pit (excavated depression) in the ground th at is used to separate oil, water, and sand from oil production operations. For the p urpose of estimating emissions, sumps can be separated into the following three cla sses based upon the stage within the treatment process:

• First stage (primary) production sump: A sump tha t receives a stream of crude oil and produced water directly from one or m ore oil production wells or field gathering systems.

• Second stage (secondary) production sump: A sump that receives waste water streams (water/oil) from one or more first st age separators (including first stage sumps and/or tanks).

• Third stage (tertiary) production sump: A sump th at receives waste water streams (water/oil) from one or more second stage s eparators (including second stage sumps and/or tanks). In most cases, th ere are only small amounts of oil present in the waste streams. Sumps are also classified based upon the type of pe troleum they receive:

• Light oil service sumps: Sumps which contain crude oil having an American Petroleum Institute’s (API) gravity of 30o or great er.

• Heavy oil service sumps: Sumps which contain crude oil having an API gravity less than 30o.

WELL CELLARS:

A well cellar is a lined or unlined containment sur rounding one or more wellheads, allowing access to the wellhead components for serv icing and/or installation of blowout prevention equipment. A well cellar is des igned to catch any liquid that may leak or spill from wellhead maintenance operations or faulty well equipment. As with sumps, well cellars are also classified based upon the type of petroleum they receive. This methodology estimates fugitive emissions of VO Cs from sumps and well cellars. For this emissions inventory, the Distric t surveyed the oil and gas production industry to determine the total surface area of fir st, second and third stage heavy and light oil sumps; as well as, the total surface area of heavy and light oil well cellars in the District. The total surface area of each sump and well cellar was then multiplied by an emission factor to estimate VOC em issions.310 – Oil Production Sumps & Well Cellars

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## V. Activity Data
Oil production facilities within the District were surveyed to determine the number and surface area of active sumps and well cellars. A copy of the survey form is included in Appendix A. Industry response to the s urvey is presented in the following table:
Table 2. Oil production facility response to the District’s sump and well cellar survey (2007). Surveys Facility Type Mailed

(no.) Returned

(no.) Returned

(%) Large Operations 1 39 37 94.9 Small Operations 228 173 75.9 TOTAL 267 210 78.7
1 Large Operations: Operations subject to District R ule 2520 (Federally Mandated Operating Permits) 

### The number of active sumps and well cellars by faci lity size and oil specific gravity are presented in the following table:
Table 3. Survey results of the number of sumps and well cellars in the District by facility size and oil specific gravity (2007).

Classification First Stage

Sumps (no.) Second Stage

Sumps (no.) Third State

Sumps (no.) Well Cellars

(no.) Large Operations Light Oil 0 0 0 1,907 Heavy Oil 0 0 1 2,643 Small Operations Light Oil 0 6 10 972 Heavy Oil 0 34 44 1,275 TOTAL Light Oil 0 6 10 2,879 Heavy Oil 0 34 45 3,918310 – Oil Production Sumps & Well Cellars

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### The surface area of active sumps and well cellars b y facility size and oil specific gravity are presented in the following table:
Table 4. Survey results of the surface area of sum ps and well cellars in the District by facility size and oil specific gravity (2007).

Classification First Stage

Sumps (ft 2 ) Second Stage

Sumps (ft 2 ) Third Stage

Sumps (ft 2 ) Well

Cellars (ft 2 ) Large Operations Light Oil 0 0 0 113,761 Heavy Oil 0 0 4,800 135,281 Small Operations Light Oil 0 4,266 35,206 61,254 Heavy Oil 0 68,372 103,829 38,763 TOTAL 0 Light Oil 0 4,266 35,206 175,015 Heavy Oil 0 68,372 108,629 174,044


### The average facility sump and well cellar surface a rea was then calculated for large and small, heavy and light oil operations. For example: average surface area of large operati ons heavy oil third stage sumps

Ave surface area 3° sumps ft2 

### = ∑ surface area 3° sumps ft2 

### ÷ ∑ facilities reporting 3° sumps

Table 5. Facility average surface area of sumps an d well cellars in the District by facility size and oil specific gravity (2007).

Classification First Stage

Sumps (ft 2 ) Second Stage

Sumps (ft 2 ) Third Stage

Sumps (ft 2 ) Well

Cellars (ft 2 ) Large Operations Light Oil 0 0 0 8,125.81 Heavy Oil 0 0 320.0 9,018.75 Small Operations Light Oil 0 101.57 838.24 1,458.42 Heavy Oil 0 876.56 1,331.14 496.96



### Sump and well cellar surface area was then adjusted to account for facilities that did not respond to the survey. For facilities that did not respond to the survey, an average value (see Table 5) was assumed based on th e non-responding facility’s size and oil specific gravity (Large: 2 heavy oil; Small: 33 heavy and 20 light oil).310 – Oil Production Sumps & Well Cellars

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Table 6. Adjusted surface area of sumps and well c ellars in the District by facility size and oil specific gravity. Results ad justed to account for facilities that did not respond to the survey (2007 ).

Classification First Stage

Sumps (ft 2 ) Second Stage

Sumps (ft 2 ) Third Stage

Sumps (ft 2 ) Well

Cellars (ft 2 ) Large Operations Light Oil 0 0 0 113,761 Heavy Oil 0 0 5,440 153,319 Small Operations Light Oil 0 6,297 51,971 77,654 Heavy Oil 0 97,298 147,757 55,163 TOTAL Light Oil 0 6,297 51,971 191,415 Heavy Oil 0 97,298 153,197 208,481



## VI. Emission Factors
Emission factors for crude oil production sumps and cellars are from a correction made to the Technical Guidance Document for the Emi ssion Inventory Criteria and Guidelines Regulation for AB 2588 (Air Toxics “Hot Spots” Information and Assessment Act of 1987) by the Kern County Air Poll ution Control District (see the memo presented in Appendix B) These emission facto rs are summarized in the following table:

Table 7. Uncontrolled emission factors for oil sum ps. Sump Classification Total Organic Gas (lb/ft 2 -day) Fractional Reactive Organic Gas 

### * Reactive Organic Gas (lb/ft 2 -day) Heavy Oil (API <30°) First Stage 0.10459 0.80 0.0837 Second Stage 0.05149 0.80 0.0412 Third Stage 0.00641 0.80 0.0051 Light Oil (API > 30°) First Stage 0.143 0.80 0.1144 Second Stage 0.02 0.80 0.016 Third Stage 0.01 0.80 0.008



### * See Appendix B: “Revised Technical Guidance Docu ment” (ROG = 80% of TOG)



### The emission factors for first stage sumps were use d for well cellars.310 – Oil Production Sumps & Well Cellars

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## VII. Emissions Calculations
A. Assumptions 1. “Active” sumps are first, second, and third stag e sumps used exclusively for the separation of crude petroleum from water pr oduced during production. 2. Total sump and well cellar area and classificati on (heavy/light oil, first/second/third stage sumps) as reported through the District’s survey are accurate. 3. Emissions from active sumps are uncontrolled.

4. The method used to account for facilities that d id not respond to the District’s survey accurately represents their sump and well cellar area. 5. Second and third stage sumps contain fluid 365 d ays per year. 6. The emission factors for oil sumps are independe nt of temperature, and emissions activity is assumed to be uniform through out the year. 7. Well cellars receive fluid 1 day per year (lette r from Chevron dated October 17, 2000).

B. Sample Calculations VOC emissions from light oil sumps in Kern County:
Step 1. Multiply the total area (ft 2 

### ) of each stage sump by the appropriate emission factor for light oil (API > 30o) times 365 days/year.

year days x x ft area sump stage First 365 day ft VOC lbs 0.0837 ) ( VOC 2 2 lbs sumps, stage

- First

− − = 

## ∑

year days x x 365

day ft VOC lbs 0.0412 ) (ft area sump stage Second VOC 2 2 lbs sumps, stage

- Second

−

= 

## ∑

year days x 365

day ft VOC lbs 0.0051 ) (ft area sump stage Third VOC 2 2 lbs sumps, stage

- Third ×

− = 

## ∑

Example:

year VOC lbs
year days x x ft 0 365 day ft VOC lbs 0.0837 0 VOC 2 2 lbs sumps, stage

- First =

− =310 – Oil Production Sumps & Well Cellars

Page 7 of 15 Rev. Date: 23 Jan 09 SumpsCellars2007_modified 06February09.doc Rev. By: G. Stewart year VOC lbs
year days x x ft 999
, 34 365 day ft VOC lbs 0.016 993 ,5 VOC 2 2 lbs sumps, stage

- Second =

− =

year VOC lbs
year days x x ft 562
, 111 365 day ft VOC lbs 0.008 206
, 38 VOC 2 2 lbs sumps, stage

- Third =

− =



### Step 2. Add the annual VOC emissions for each sump stage an d multiply by 1 ton over 2,000 lbs to obtain the annual VOC emissio ns in tons of VOC per year. 

# [ ] lbs 000 ,2 ton 1 * VOC lbs VOC lbs VOC lbs VOC sumps stage

- Third sumps stage

- Second sumps stage

- First tons , total Sump 

## + + =

Example:



### year VOC tons lbs ton
year VOC tons

total Sump 

### 28. 73 000 ,2 1 * VOC lbs 111,562
year VOC lbs 34,999
year VOC lbs 0

, 

### =       +

+ =



## VIII. Temporal Variation
We assume sump emissions are independent of tempera ture, and emissions activity is uniform throughout the year. A. Daily CARB Code 24. 24 hours per day - uniform activity during the day. B. Weekly CARB Code 7. 7 days per week - uniform activity e very day of the week C. Monthly
Uniform monthly activity. 8.33% per month We assume well cellars receive fluid one day per ye ar. 

## IX. Spatial Variation
Oil production facilities are located in the Centra l and Southern Regions of the District, with the heaviest concentration in Kern C ounty.310 – Oil Production Sumps & Well Cellars

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## X. Growth Factor
Growth factors are developed by either the District ’s Planning Department or CARB for each EIC. These factors are used to estimate e missions in future years. The growth factors associated with this emissions categ ory may be obtained from the Air Quality Analysis Section of the District’s Planning Department.



## XI. Control Level
Control levels are developed by either the District ’s Planning Department or CARB for each EIC. Control levels are used to estimate emissions reductions in future years due to implementation of District rules. The se control levels take into account the effect of control technology, compliance and ex emptions at full implementation of the rules. Oil sumps are subject to District Rule 4402 (Crude Oil Production Sumps). Control levels associated with this emissions category may be obtained from the Air Quality Analysis Section of the District’s Planning Departm ent.


## XII. ARB Chemical Speciation
CARB has developed organic gas profiles in order to calculate reactive organic gasses (ROG), volatile organic compounds (VOC) or t otal organic gas (TOG) given any one of the three values. For each speciation p rofile, the fraction of TOG that is ROG and VOC is given. The organic gas profile codes can also be used to lookup associated toxics. CARB’s speciation profiles for fugitive emissions from oil sumps and well cellars is presented in Table 8.



## XIII. Assessment Of Methodology
The accuracy of this estimate is dependent upon dat a provided to the District by the oil production industry (SIC 1311) through our surv ey. Our estimate excludes any pits, ponds or sumps not used for separating crude oil such as those used to for clean produced water; the EPA’s Spill Prevention, Control, and Countermeasure Rule (SPCC); inactive units, etc. Table 8 . CARB organic gas speciation profiles for oil su mps (profile 537) and well cellars (profile 532). Fractions Profile Description CARB Organic Gas Profile# ROG VOC Crude Oil – Sumps, Wells, HOTS, Kern Co 537 0.912* 0.912* Oil & Gas Extraction – Well Heads & Cellars/Oil & Water Separators 532 0.606 0.606

* These values differ from what the District uses. S ee Revised Technical Guidance document (ROG = 80% of TOG)310 – Oil Production Sumps & Well Cellars

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### When ARB calculated oil sump emissions in 1993, the y used an emission factor (EF) of 0.0515 lbs ROG/ft 2 

### -day for second stage heavy oil sumps. In this methodology, the District uses an emission factor o f 0.0412 lbs ROG/ft 2 

### -day for second stage heavy oil sumps. This emission factor represents a 3.6 fold decrease in lbs ROG/ft 2 

### -day compared to the one used in the previous estim ate. The impact of this change is demonstrated below for Kern Count y’s 78,798 ft 2 

### of second stage heavy oil sumps:

year tons lbs ton x year days x day ft VOC lbs x year ft EF ARB 29. 742 000 ,2 1 365 0515 .0 798
, 78

2

2



### =

− =

year tons lbs ton x year days x day ft VOC lbs x year ft EF District 84. 593 000 ,2 1 365 0412 .0 978
, 78

2

2



### =

− =

As demonstrated above, this change results in an de crease of 148 tons per year of VOC in Kern County due to the use of the new emissi on factor for second stage heavy oil sumps.



## XIV. Emissions
Since oil sumps and well cellars are not represente d in the Districts point source inventory, the total unreconciled emissions are equ al to the area source emissions. Following is the 2007 total unreconciled (point sou rce plus area source) emissions inventory for oil sumps and well cellars. Emission s are reported for each county in the District.
Table 9. Total emissions for oil sumps and well cel lars (2007). Emissions (tons/year) County NOx CO SOx VOC (1) PM 10 PM 2.5 (2) Oil Production Fugitive losses – Sumps and Pits (31 0-300-1600-0000) Fresno N/A N/A N/A 9.75 N/A N/A Kern N/A N/A N/A 761.35 N/A N/A Kings N/A N/A N/A 0.00 N/A N/A Madera N/A N/A N/A 0.00 N/A N/A Merced N/A N/A N/A 0.00 N/A N/A San Joaquin N/A N/A N/A 0.00 N/A N/A Stanislaus N/A N/A N/A 0.00 N/A N/A Tulare N/A N/A N/A 197.34 N/A N/A TOTAL N/A N/A N/A 968.44 N/A N/A Oil Production Fugitive losses – Well Cellars (310- 312-1600-0000) Fresno N/A N/A N/A 1.11 N/A N/A Kern N/A N/A N/A 19.01 N/A N/A Kings N/A N/A N/A 0.12 N/A N/A Madera N/A N/A N/A 0.00 N/A N/A Merced N/A N/A N/A 0.00 N/A N/A San Joaquin N/A N/A N/A 0.00 N/A N/A Stanislaus N/A N/A N/A 0.00 N/A N/A Tulare N/A N/A N/A 0.17 N/A N/A TOTAL N/A N/A N/A 20.41 N/A N/A310 – Oil Production Sumps & Well Cellars

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(1) The District only reports ROG to CARB. As not ed in Section XII, ROG is the same as VOC.310 – Oil Production Sumps & Well Cellars

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### Following is the net change in total unreconciled e missions between this update (2007 inventory year) and CEIDARS data for the prev ious year (2006 inventory year) for oil sumps and well cellars. The changes in emi ssions are reported for each county in the District.
Table 10. Net emissions change for oil sumps and we ll cellars (2007). Emissions (tons/year) County NOx CO SOx VOC (1) PM 10 PM 2.5 (2) Oil Production Fugitive losses – Sumps and Pits (31 0-300-1600-0000) Fresno N/A N/A N/A -9.13 N/A N/A Kern N/A N/A N/A 645.17 N/A N/A Kings N/A N/A N/A -20.16 N/A N/A Madera N/A N/A N/A 0 N/A N/A Merced N/A N/A N/A 0 N/A N/A San Joaquin N/A N/A N/A 0 N/A N/A Stanislaus N/A N/A N/A 0 N/A N/A Tulare N/A N/A N/A 197.34 N/A N/A TOTAL N/A N/A N/A 813.22 N/A N/A Oil Production Fugitive losses – Well Cellars (310- 312-1600-0000) Fresno N/A N/A N/A -0.73 N/A N/A Kern N/A N/A N/A -23.42 N/A N/A Kings N/A N/A N/A 0.04 N/A N/A Madera N/A N/A N/A 0 N/A N/A Merced N/A N/A N/A 0 N/A N/A San Joaquin N/A N/A N/A 0 N/A N/A Stanislaus N/A N/A N/A 0 N/A N/A Tulare N/A N/A N/A 0.11 N/A N/A TOTAL N/A N/A N/A -24.04 N/A N/A (1) The District only reports ROG to CARB. As note d in Section XII, ROG is the same as VOC.



## XV. Revision History
2007. This is a new District methodology based on a survey of oil producers.


## XVI. Update Schedule
The area source categories within this methodology have update authority “B” codes. This means that ARB develops default emissi ons for these sources, but Districts may overwrite them subject to ARB review and approval. Since the District is not directly responsible for maintaining these a rea source categories, they will only be updated as needed.310 – Oil Production Sumps & Well Cellars

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## XVII. References

1. Kern County Air Pollution Control District. 199 0. Corrections to CARB’s AB 2588 Air “Hot Spots” technical guidance document, T able D-1, Page 118.

2. California Air Resources Board. 2004. Definiti ons of VOC and ROG http://www.arb.ca.gov/ei/speciate/definitions.htm

3. California Air Resources Board Technical Review Group. 1988. Technical support document for suggested control measure for the control of organic compound emissions from sumps used in oil productio n operations. 4. Clark, L. 2007. Independent Oil Producers Agen cy. Personal Communication via e-mail and visit. 5. Eaton, W.S. 1980. Fugitive hydrocarbon emission s from petroleum production operations. 6. Funk, T.H. 2003. Emission inventory methodolog y – Oil and gas sumps. Somona Technology, Inc., Petaluma, CA. 7. Gunderson, D. 2007. Aera Energy. Personal Com munication via e-mail. 8. San Joaquin Valley Air Pollution Control Distric t. 2000. Rule 4441 (Draft): Well cellars and sumps. 9. San Joaquin Valley Air Pollution Control Distric t. 1991. Rule 4402: Crude oil production sumps. http://www.valleyair.org/rules/c urrntrules/r4401.pdf 10. United States Environmental Protection Agency. 1993. Supplement D to Compilation of Emission Factors (AP-42), U.S. GPO, Washington D.C., 1993. http://www.epa.gov/ttn/chief/ap42/



## XVIII. Appendices

Appendix A. District Sump and Well Cellar Survey Appendix B. Memo from Kern Co. APCD: Revised Techn ical Guidance Document310 – Oil Production Sumps & Well Cellars

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### Appendix A. District Sump and Well Cellar Survey



# Active Sump and Well Cellar Data For Calendar Year 2007

Please complete this Emissions Inventory survey and return to any of the District offices. The data w ill be used to improve the District’s area-wide emissio n inventory. This information is vital to ensure that future air pollution control plans and rules reflec t actual emissions and do not overestimate your industry’s emissions. Thank you for your assistanc e. If you have any questions please call Maya Hildebrand-Garcia at (559) 230-5934.
The questions below refer only to active sumps used as first, second, and third-stage production sumps . It does not refer to sumps used to for clean produced water, the EPA’s (Spill Prevention, Control, and Countermeasure Rule (SPCC), evaporation, precipitat ion, percolation, or any pits and ponds not used fo r separating crude oil.

1. Light Crude Oil (>30o API Gravity)
Production Sumps Total number Total area (square f eet) First Stage Second Stage Third Stage Well cellars
2. Heavy Crude Oil (<30o API Gravity)
Production Sumps Total number Total area (square f eet) First Stage Second Stage Third Stage Well cellars

3. Comments:



### 4. Contact Information
Facility name: _____________________________________

________________________ Contact person: ____________________________________

________________________ Address: ___________________________________________

______________________ Telephone:_______________FAX: ________________E-mail

______________________310 – Oil Production Sumps & Well Cellars

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### Appendix B. Revised Technical Guidance Document310 – Oil Production Sumps & Well Cellars

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