#•	\

\ d?

PRO*^

2020 National Emissions Inventory Technical
Support Document: Oil and Gas Exploration
and Production


-------

-------
EP A-454/R-23 -001 m
March 2023

2020 National Emissions Inventory Technical Support Document: Oil and Gas Exploration and

Production

U.S. Environmental Protection Agency
Office of Air Quality Planning and Standards
Air Quality Assessment Division
Research Triangle Park, NC


-------
Contents

List of Tables	i

13	Oil and Gas Exploration and Production	13-1

13.1	Sector Descriptions and Overview	13-1

13.2	Sources of data	13-5

13.3	EPA-developed estimates	13-7

13.3.1	Activity data	13-8

13.3.2	FIPS changes and Temperature changes	13-8

13.3.3	Basin factors	13-8

13.3.4	Emission factors	13-9

13.3.5	Methodology Updates	13-9

13.3.6	Point source subtraction	13-9

13.3.7	Other State-specific correspondence	13-9

13.4	References	Error! Bookmark not defined.

List of Tables

Table 13-1: Point and Nonpoint SCCs used for the Oil and Gas Production Sector	13-1

Table 13-2: Data Source for Oil and Gas Production Data in the 2020 NEI	13-6

List of Figures

Figure 13-1: Data source for Oil and Gas emissions	13-5

l


-------
13 Oil and Gas Exploration and Production

13.1 Sector Descriptions and Overview

This sector includes processes associated with the exploration and drilling at oil, gas, and coal bed
methane (CBM) wells and the equipment used at the well sites to extract the product from the well and
deliver it to a central collection point or processing facility.

Table 13-1 lists the processes below with their corresponding SCCs; the SCCs used by EPA to estimate
nonpoint emissions are marked in second column. Note also that the SCCs in this list are only the SCCs
that either the EPA used or the submitting State agencies used in this NEI. All of the SCCs that the EPA oil
and gas tool uses are nonpoint SCCs. Lastly, Y marked with an asterisk (Y*) denote SCCs that are
produced by the tool, but only for the state of Pennsylvania, by special request.

Table 13-1: Point and Nonpoint SCCs used for the Oil and Gas Production Sector

Data
Category

EPA
uses

see

SCC Description (Abbreviated)

Nonpoint

Y

2310000220

All Processes; Drill Rigs

Nonpoint



2310000230

All Processes; Workover Rigs

Nonpoint

Y

2310000551

All Processes; Produced Water from CBM Wells

Nonpoint

Y

2310000552

All Processes; Produced Water from Gas Wells

Nonpoint

Y

2310000553

All Processes; Produced Water from Oil Wells

Nonpoint

Y

2310000660

All Processes; Hydraulic Fracturing Engines

Nonpoint



2310001000

All Processes: On-shore; Total: All Processes

Nonpoint



2310002000

Off-Shore Oil and Gas Production; Total: All Processes

Nonpoint



2310002401

Off-Shore Oil and Gas Production; Pneumatic Pumps: Gas And Oil
Wells

Nonpoint



2310002411

Off-Shore Oil and Gas Production; Pressure/Level Controllers

Nonpoint



2310002421

Off-Shore Oil and Gas Production; Cold Vents

Nonpoint

Y

2310010100

Crude Petroleum; Oil Well Heaters

Nonpoint

Y

2310010200

Crude Petroleum; Oil Well Tanks - Flashing & Standing /Working
/Breathing

Nonpoint

Y

2310010300

Crude Petroleum; Oil Well Pneumatic Devices

Nonpoint



2310010700

Crude Petroleum; Oil Well Fugitives

Nonpoint

Y

2310011001

On-Shore Oil Production; Associated Gas Venting

Nonpoint



2310011020

On-Shore Oil Production; Storage Tanks: Crude Oil

Nonpoint



2310011100

On-Shore Oil Production; Heater Treater

Nonpoint

Y

2310011201

On-Shore Oil Production; Tank Truck/Railcar Loading: Crude Oil

Nonpoint



2310011450

On-Shore Oil Production; Wellhead

Nonpoint



2310011500

On-Shore Oil Production; Fugitives: All Processes

Nonpoint

Y

2310011501

On-Shore Oil Production; Fugitives: Connectors

Nonpoint

Y

2310011502

On-Shore Oil Production; Fugitives: Flanges

13-1


-------
Nonpoint

Y

2310011503

On-Shore Oil Production; Fugitives: Open Ended Lines

Nonpoint



2310011504

On-Shore Oil Production; Fugitives: Pumps

Nonpoint

Y

2310011505

On-Shore Oil Production; Fugitives: Valves

Nonpoint



2310011506

On-Shore Oil Production; Fugitives: Other

Nonpoint

Y

2310011600

On-Shore Oil Production; Artificial Lift Engines

Nonpoint



2310012000

Off-Shore Oil Production; Total: All Processes

Nonpoint



2310012020

Off-Shore Oil Production; Storage Tanks: Crude Oil

Nonpoint



2310012516

Off-Shore Oil Production; Fugitives, Other: Oil

Nonpoint



2310012526

Off-Shore Oil Production; Fugitives, Other: Oil/Water

Nonpoint

y*

2310020600

Natural Gas; Compressor Engines

Nonpoint

Y

2310021010

On-Shore Gas Production; Storage Tanks: Condensate

Nonpoint



2310021011

On-Shore Gas Production; Condensate Tank Flaring

Nonpoint

Y

2310021030

On-Shore Gas Production; Tank Truck/Railcar Loading: Condensate

Nonpoint

Y

2310021100

On-Shore Gas Production; Gas Well Heaters







On-Shore Gas Production; Natural Gas Fired 2Cycle Lean Burn

Nonpoint



2310021101

Compressor Engines < 50 HP







On-Shore Gas Production; Natural Gas Fired 2Cycle Lean Burn

Nonpoint

Y

2310021102

Compressor Engines 50 To 499 HP







On-Shore Gas Production; Natural Gas Fired 2Cycle Lean Burn

Nonpoint



2310021103

Compressor Engines 500+ HP







On-Shore Gas Production; Total: All Natural Gas Fired 2Cycle Lean

Nonpoint



2310021109

Burn Compressor Engines







On-Shore Gas Production; Natural Gas Fired 4Cycle Lean Burn

Nonpoint



2310021201

Compressor Engines <50 HP







On-Shore Gas Production; Natural Gas Fired 4Cycle Lean Burn

Nonpoint

Y

2310021202

Compressor Engines 50 To 499 HP







On-Shore Gas Production; Natural Gas Fired 4Cycle Lean Burn

Nonpoint



2310021203

Compressor Engines 500+ HP







On-Shore Gas Production; Total: All Natural Gas Fired 4Cycle Lean

Nonpoint



2310021209

Burn Compressor Engines

Nonpoint

Y

2310021251

On-Shore Gas Production; Lateral Compressors 4 Cycle Lean Burn

Nonpoint

Y

2310021300

On-Shore Gas Production; Gas Well Pneumatic Devices







On-Shore Gas Production; Natural Gas Fired 4Cycle Rich Burn

Nonpoint



2310021301

Compressor Engines <50 HP







On-Shore Gas Production; Natural Gas Fired 4Cycle Rich Burn

Nonpoint

Y

2310021302

Compressor Engines 50 To 499 HP







On-Shore Gas Production; Natural Gas Fired 4Cycle Rich Burn

Nonpoint



2310021303

Compressor Engines 500+ HP







On-Shore Gas Production; Total: All Natural Gas Fired 4Cycle Rich

Nonpoint



2310021309

Burn Compressor Engines

Nonpoint

Y

2310021310

On-Shore Gas Production; Gas Well Pneumatic Pumps

Nonpoint

Y

2310021351

On-Shore Gas Production; Lateral Compressors 4 Cycle Rich Burn

Nonpoint

Y

2310021400

On-Shore Gas Production; Gas Well Dehydrators

13-2


-------






On-Shore Gas Production; Nat Gas Fired 4Cycle Rich Burn

Nonpoint



2310021401

Compressor Engines <50 HP w/NSCR







On-Shore Gas Production; Nat Gas Fired 4Cycle Rich Burn

Nonpoint



2310021402

Compressor Engines 50 To 499 HP w/NSCR







On-Shore Gas Production; Nat Gas Fired 4Cycle Rich Burn

Nonpoint



2310021403

Compressor Engines 500+ HP w/NSCR

Nonpoint



2310021412

On-Shore Gas Production; Gas Well Dehydrators/Reboiler

Nonpoint



2310021450

On-Shore Gas Production; Wellhead

Nonpoint

Y

2310021500

On-Shore Gas Production; Gas Well Completion - Flaring

Nonpoint

Y

2310021501

On-Shore Gas Production; Fugitives: Connectors

Nonpoint

Y

2310021502

On-Shore Gas Production; Fugitives: Flanges

Nonpoint

Y

2310021503

On-Shore Gas Production; Fugitives: Open Ended Lines

Nonpoint



2310021504

On-Shore Gas Production; Fugitives: Pumps

Nonpoint

Y

2310021505

On-Shore Gas Production; Fugitives: Valves

Nonpoint

Y

2310021506

On-Shore Gas Production; Fugitives: Other

Nonpoint



2310021509

On-Shore Gas Production; Fugitives: All Processes

Nonpoint



2310021600

On-Shore Gas Production; Gas Well Venting

Nonpoint



2310021602

On-Shore Gas Production; Gas Well Venting - Recompletions

Nonpoint

Y

2310021603

On-Shore Gas Production; Gas Well Venting - Blowdowns

Nonpoint



2310021700

On-Shore Gas Production; Miscellaneous Engines

Nonpoint

Y

2310021801

On-Shore Gas Production; Pipeline Blowdowns and Pigging

Nonpoint



2310021802

On-Shore Gas Production; Pipeline Leaks







On-Shore Gas Production; Midstream gas venting for maintenance,

Nonpoint



2310021803

startup, shutdown, or malfunction

Nonpoint



2310022000

Off-Shore Gas Production; Total: All Processes

Nonpoint



2310022010

Off-Shore Gas Production; Storage Tanks: Condensate

Nonpoint



2310022051

Off-Shore Gas Production; Turbines: Natural Gas

Nonpoint



2310022090

Off-Shore Gas Production; Boilers/Heaters: Natural Gas

Nonpoint



2310022105

Off-Shore Gas Production; Diesel Engines

Nonpoint



2310022300

Off-Shore Gas Production; Compressor Engines: 4Cycle Rich

Nonpoint



2310022420

Off-Shore Gas Production; Dehydrator

Nonpoint



2310022506

Off-Shore Gas Production; Fugitives, Other: Gas

Nonpoint

Y

2310023000

Coal Bed Methane Natural Gas; Dewatering Pump Engines

Nonpoint

Y

2310023010

Coal Bed Methane Natural Gas; Storage Tanks: Condensate







Coal Bed Methane Natural Gas; Tank Truck/Railcar Loading:

Nonpoint

Y

2310023030

Condensate

Nonpoint

Y

2310023100

Coal Bed Methane Natural Gas; CBM Well Heaters







Coal Bed Methane Natural Gas; CBM Fired 2Cycle Lean Burn

Nonpoint

Y

2310023102

Compressor Engines 50 To 499 HP







Coal Bed Methane Natural Gas; CBM Fired 4Cycle Lean Burn

Nonpoint

Y

2310023202

Compressor Engines 50 To 499 HP







Coal Bed Methane Natural Gas; Lateral Compressors 4 Cycle Lean

Nonpoint

Y

2310023251

Burn

13-3


-------
Nonpoint

Y

2310023300

Coal Bed Methane Natural Gas; Pneumatic Devices







Coal Bed Methane Natural Gas; CBM Fired 4Cycle Rich Burn

Nonpoint

Y

2310023302

Compressor Engines 50 To 499 HP

Nonpoint

Y

2310023310

Coal Bed Methane Natural Gas; Pneumatic Pumps







Coal Bed Methane Natural Gas; Lateral Compressors 4 Cycle Rich

Nonpoint

Y

2310023351

Burn

Nonpoint

Y

2310023400

Coal Bed Methane Natural Gas; Dehydrators

Nonpoint



2310023401

Coal Bed Methane Natural Gas; Dehydrators/Reboiler

Nonpoint



2310023509

Coal Bed Methane Natural Gas; Fugitives

Nonpoint

Y

2310023511

Coal Bed Methane Natural Gas; Fugitives: Connectors

Nonpoint

Y

2310023512

Coal Bed Methane Natural Gas; Fugitives: Flanges

Nonpoint

Y

2310023513

Coal Bed Methane Natural Gas; Fugitives: Open Ended Lines

Nonpoint

Y

2310023515

Coal Bed Methane Natural Gas; Fugitives: Valves

Nonpoint

Y

2310023516

Coal Bed Methane Natural Gas; Fugitives: Other







Coal Bed Methane Natural Gas; CBM Well Completion: All

Nonpoint

Y

2310023600

Processes

Nonpoint

Y

2310023603

Coal Bed Methane Natural Gas; CBM Well Venting - Blowdowns

Nonpoint

Y

2310023606

Coal Bed Methane Natural Gas; Mud Degassing







Natural Gas Liquids: Gas Well Tanks - Flashing &

Nonpoint



2310030220

Standing/Working/Breathing, Controlled

Nonpoint



2310030300

Natural Gas Liquids; Gas Well Water Tank Losses

Nonpoint



2310030400

Natural Gas Liquids; Truck Loading

Nonpoint

Y

2310111100

On-Shore Oil Exploration; Mud Degassing

Nonpoint

Y

2310111401

On-Shore Oil Exploration; Oil Well Pneumatic Pumps

Nonpoint

Y

2310111700

On-Shore Oil Exploration; Oil Well Completion: All Processes

Nonpoint



2310111701

On-Shore Oil Exploration; Oil Well Completion: Flaring

Nonpoint



2310112401

Off-Shore Oil Exploration; Oil Well Pneumatic Pumps

Nonpoint

Y

2310121100

On-Shore Gas Exploration; Mud Degassing

Nonpoint

Y

2310121401

On-Shore Gas Exploration; Gas Well Pneumatic Pumps

Nonpoint

Y

2310121700

On-Shore Gas Exploration; Gas Well Completion: All Processes

Nonpoint



2310122000

Off-Shore Gas Exploration; All Processes

Nonpoint

Y*

2310300220

All Processes - Conventional; Drill Rigs







On-Shore Gas Production - Conventional; Storage Tanks:

Nonpoint

Y*

2310321010

Condensate

Nonpoint

Y*

2310321100

On-Shore Gas Production - Conventional; Gas Well Heaters

Nonpoint

y*

2310321400

On-Shore Gas Production - Conventional; Gas Well Dehydrators







On-Shore Gas Production - Conventional; Gas Well Venting -

Nonpoint

Y*

2310321603

Blowdowns

Nonpoint

Y*

2310400220

All Processes - Unconventional; Drill Rigs







On-Shore Gas Production - Unconventional; Storage Tanks:

Nonpoint

Y*

2310421010

Condensate

Nonpoint

Y*

2310421100

On-Shore Gas Production - Unconventional; Gas Well Heaters

13-4


-------
Nonpoint

Y*

2310421400

On-Shore Gas Production - Unconventional; Gas Well Dehydrators

Nonpoint

Y*

2310421603

On-Shore Gas Production - Unconventional; Gas Well Venting -
Slowdowns

13.2 Sources of data

For the nonpoint data category, S/L/Ts have four options for providing data to the NEI for the Oil and
Gas Production Sector. They may: 1) accept the tool with the defaults populated in the tool by EPA, 2)
choose to provide EPA with input data to incorporate in the tool, 3) run the tool themselves (presumably
updating the inputs and subtracting point sources), or 4) use their own tools and methodology to
provide estimates. In addition, some S/L/Ts submit emissions data for the point data category. Figure
13-1 shows these state-level data sources for the oil and gas sector.

Figure 13-1: Data source for Oil and Gas emissions

asto'sife

.Allegheny^

[Douglay
Kountw

Wefferson]
¦CsQuntfl

yy//% o up tyo u n ty '

¦Email
County]

Oil and Gas Data Source Map 2020 NEI

Data Source

EPA Tool

IH EPA Tool with revised inputs

mm EPA Tool with revised inputs and
SLT Nonpoint

EPA Tool and SLT Nonpoint
| SLT Nonpoint
Y//A SLT Point

Esn, FAO, NOAA. USGS

Table 13-2 summarizes the data that was submitted by states in the oil and gas production sector for
both point and nonpoint.

13-5


-------
Table 13-2: Data Source for Oil and Gas Production Data in the 2020 NEI

State

Nonpoint

Point

AL

EPA estimates only

Submitted to Point Inventory

AK

EPA estimates and SLT

Submitted to Point Inventory

Allegheny



Submitted to Point Inventory

AZ

EPA estimates only

Submitted to Point Inventory

AR

EPA estimates only

Submitted to Point Inventory

CA

SLT only

Submitted to Point Inventory

CO

EPA estimates and SLT

Submitted to Point Inventory

CT



Submitted to Point Inventory

DE



Submitted to Point Inventory

FL

EPA estimates only

Submitted to Point Inventory

GA



Submitted to Point Inventory

ID

EPA estimates only



IL

EPA estimates only

Subm

tted to Point Inventory

IA



Subm

tted to Point Inventory

IN

EPA estimates only

Subm

tted to Point Inventory

Jefferson City



Subm

tted to Point Inventory

KS

EPA Tool with revised inputs

Subm

tted to Point Inventory

KY

EPA estimates only

Subm

tted to Point Inventory

Louisville

EPA estimates only

Subm

tted to Point Inventory

LA

EPA estimates only

Subm

tted to Point Inventory

MA



Subm

tted to Point Inventory

MD

EPA estimates only

Subm

tted to Point Inventory

ME



Subm

tted to Point Inventory

Memphis



Subm

tted to Point Inventory

Ml

EPA estimates only

Subm

tted to Point Inventory

MN



Subm

tted to Point Inventory

MS

EPA estimates only

Subm

tted to Point Inventory

MO

EPA estimates only

Subm

tted to Point Inventory

MT

EPA estimates only

Subm

tted to Point Inventory

Nashville



Subm

tted to Point Inventory

NE

EPA estimates only

Subm

tted to Point Inventory

NJ

SLT only

Subm

tted to Point Inventory

NV

EPA estimates only

Subm

tted to Point Inventory

NM

EPA Tool with revised inputs

Subm

tted to Point Inventory

NY

EPA estimates only

Subm

tted to Point Inventory

ND

EPA estimates only

Subm

tted to Point Inventory

OH

EPA estimates and SLT

Subm

tted to Point Inventory

OK

EPA Tool with revised inputs and SLT

Subm

tted to Point Inventory

OR

EPA estimates only

Subm

tted to Point Inventory

Omaha



Subm

tted to Point Inventory

PA

EPA Tool with revised inputs

Subm

tted to Point Inventory

13-6


-------
Pinal



Submitted to Point Inventory

SC



Submitted to Point Inventory

SD

EPA estimates only



TN

EPA estimates only

Submitted to Point Inventory

TX

EPA Tool with revised inputs and SLT

Submitted to Point Inventory

UT

EPA Tool and SLT

Submitted to Point Inventory

VA

EPA estimates only

Submitted to Point Inventory

WV

EPA Tool with revised inputs and SLT

Submitted to Point Inventory

Wl



Submitted to Point Inventory

WY

SLT only

Submitted to Point Inventory

Shoshone Bannock



Submitted to Point Inventory

Southern Ute

SLT only

Submitted to Point Inventory

13.3 EPA-developed estimates

The EPA furthered the development of the existing oil and gas emissions estimation tool that was
originally developed for the 2011 NEl, which is a MS Access database that uses a bottom-up approach to
build a national inventory. More information on the tool can be found in the documentation provided by
ERG, entitled "2020 Nonpoint Oil and Gas Emission Estimation Tool, version 1.3" in the file
"2020 Oil and Gas Emissions Estimation Tool VI 3.pdf". There are two modules, as was put in place
since the 2014 tool: Exploration and Production. Changes that have been incorporated in the 2020 Oil
and Gas Production and Exploration tools since 2017 are addressed in the documentation above. In
addition, a memo outlining the additional data from the GHG Reporting Program (subpart W) is entitled
2020 NEI Oil and Gas Tool Subpart W Analysis.

In general, the tool calculates emissions for each piece of equipment on a well pad (like condensate
tanks or dehydrators, for example) in a county or basin, based on average equipment counts taken from
either surveys, literature searches, or the GHG reporting program, also accounting for control devices
and gas composition in each county. County-level details are important, since well pads can vary
significantly from region to region, basin to basin, and county to county. A well site in Denver, CO in the
Denver-Julesburg Basin might look very different from one in the Marcellus Shale in PA, due to changes
in technology over time (when the well was first drilled), geologic formations of the oil and gas
reservoirs themselves (which also change over time—the ratio of oil to gas changes as pressure in the
reservoir is released), and regulations in place guiding the equipment used on site.

The math used in the oil and gas tool is more complex than most other categories, as it uses equations
like the ideal gas law and mass balances, in conjunction with more traditional emission rate equations
(activity * EF = emissions); thus, the work is best completed in database format. Overall, there are
hundreds of inputs to the oil and gas tool, and these are broken down into three basic categories:
activity data, basin factors, and emission factors. These inputs to the tool are filled in by EPA, and
published with the tool, along with their references. Region specific inputs are preferable and are used
when available. Extrapolated inputs from nearby counties in the same basin are then used to fill in gaps
in data. National defaults are filled in where no other data is available, and attempts are made to align
inputs as much as possible with the GHG reporting program and emissions inventory.

13-7


-------
13.3.1 Activity data

The primary source of activity data for the 2020 Tool is the commercially available database developed
by Enverus called HPDI, or also called the Dl Desktop database. HPDI supplies activity such as number of
wells, oil, gas, condensate, and water production, feet drilled, spud counts, and other data. There are
cases where this data is not complete, and in those cases, EPA supplemented with data from RIGDATA,
from various state oil and gas commissions, and directly from Tool users. More details on these data can
be found in the aforementioned report. The following SLTs provided updated activity inputs for the 2020
Tool:

•	Kansas (Production)

•	Oklahoma (Production)

•	Pennsylvania (Production)

•	Texas (Production)

•	Illinois (Production)

•	West Virginia (Production/Exploration).

•

13.3.2	FIPS changes and Temperature changes

State/County FIPS codes were updated for several counties in Alaska and annual county-level average
temperatures for 2020 were updated nationally, using EPA's 2020 Weather Research Factorization
(WRF) model data.

13.3.3	Basin factors

Basin factors include factors that are secondary to activity and include assumptions about equipment
counts on a per well basis, (e.g., the number of pneumatic controllers per well, or the average HP of an
engine at a well site) as well as gas speciation profiles (fraction of benzene, toluene, xylene, or
ethylbenzene in natural gas at a particular point in the well pad, e.g., post separator).

For 2020 inputs, GHGRP data gathered under subpart W was analyzed to develop updated basin factors
for several source categories including storage tanks, dehydrators, fugitive equipment leaks, heaters,
pneumatic devices, and wellhead compressor engines. See "2020 NEl Tool Subpart W Data Analysis"
memo dated December 3, 2021.

Western Regional Air Partnership (WRAP) data was used to develop updated basin factors for several
source categories for Montana, New Mexico, North Dakota, and South Dakota. Details of the emissions
factor, speciation factor and other changes for some WRAP basins are contained in memos and
documents provided here:

https://gaftp.epa.gov/Air/nei/2020/doc/supporting data/nonpoint/oilgas/WRAP survey/.

Data provided by the California Air Resources Board (CARB) was used to develop updated basin factors
for several source categories for oil-related sources. US Energy Information Administration (EIA) data
was used to update the volumes of gas vented/flared in the associated gas venting and flaring category,
and this data can be found at the following link:

(https://www.eia.gov/dnav/ng/ng prod sum a ERGO VGV mmcf a.htm).

13-8


-------
13.3.4 Emission factors

Emission factors are also a part of the formula for estimating emissions, and in the Oil and Gas tool the
nomenclature is set such that we only call the standard national factors, like from AP-42 combustion
equations, "emission factors."

For the 2020 Tool, the following emissions factor updates occurred:

1.	Drilling and hydraulic fracturing engine emission factors were updated using the MOVES model
for 2020.

2.	The flaring CO emission factor was updated based on updates to the AP-42.

3.	A S02 emission factor from AP-42 was added for heater treaters.

13.3.5 Methodology Updates

The methodology used to estimate VOC emissions from associated gas venting and flaring was revised
to include only process-based emissions (accounting for VOC sent to the flare). The tool no longer uses
the AP-42 flaring VOC emission factor in the calculation.

13.3.6	Point source subtraction

Some states count upstream oil and gas production processes as point sources, and therefore have a
need to subtract these from the nonpoint part of the inventory. The tool allows for point source
subtraction on either an activity or emissions basis, and a few states have taken advantage of this
feature.

The state of New Mexico added a considerable number of sources to their oil and gas point source
inventory in the NEI. New Mexico provided a county-SCC summary of emissions for use in the Tool as
part of the point source subtraction functionality. Updated nonpoint emissions were generated for New
Mexico after this point source subtraction and were used in the 2020NEI.

13.3.7	Other State-specific correspondence
Oklahoma

The Oklahoma Department of Environmental Quality (OK DEQ) uses a mix of both EPA estimates (for the
exploration module) and their own emissions using the oil and gas tool (production module only). OK
DEQ allows EPA to do HAP augmentation for the SCCs that they submit. One difference between OK
DEQ's SCC emissions dataset and EPA's SCCs are that OK DEQ aggregates their equipment-specific
fugitive emissions into Fugitive All Process SCCs for oil, gas and CBM wells.

Pennsylvania

The PADEP relies on EPA to run the oil and gas tool but utilizes alternative SCCs for several source
categories in order to differentiate their emissions for conventional and unconventional oil and gas
operations. PA DEP provides unconventional well API numbers which EPA then subtracts from the tool
to determine the conventional portion. The process includes the following steps:

1. Run the tool with basin factors that the Mid-Atlantic Regional Air Management Association
(MARAMA) provided for the 2014 NEI oil and gas sector for
• Artificial lifts

13-9


-------
•	Associated gas

•	Condensate tanks

•	Crude tanks

•	Dehydrators

•	Fugitives

•	Gas-actuated pumps (oil and gas wells)

•

For associated gas, condensate tanks, crude oil tanks, and dehydrators, if the Tool sources were the
2020 GHGRP factors recently documented, these were not replaced. EPA also incorporated gas
composition profiles provided by the PA DEP.

2.	Remove the activity data related to the emissions data provided by PA using API numbers for
unconventional wells.

3.	Run the tool for adjusted emissions.

4.	Use the "conventional only" SCCs to replace the more "general" Tool SCCs for 5 source
categories:

•	Drilling

•	Gas Well Condensate Tanks

•	Gas Well Heaters

•	Gas Well Dehydrators

•	Gas Well Liquids Unloading

Details regarding the Pennsylvania emissions can be found here:

https://gaftp.epa.gov/Air/nei/2020/doc/supporting data/nonpoint/oilgas/OIL GAS TOOL vl.B/PA 202
ISSIONS 20220801.xlsx

13-10


-------
United States	Office of Air Quality Planning and Standards	Publication No. EPA-454/R-23-001m

Environmental Protection	Air Quality Assessment Division	March 2023

Agency	Research Triangle Park, NC


-------