MEMORANDUM

TO: Lisa Biddle, EPA

Karen Milam, EPA

FROM: Brent Ruminski, ERG

Sarah Yates, ERG

DATE: June 7, 2016

SUBJECT: Analysis of Active Underground Injection for Disposal Wells (DCN 

SGE01187)

This memorandum describes data and methods that ERG used to compile information on 

Underground injection wells and their relationship to the UOG industry for the Technical 

Development Document for Proposed Effluent Limitations Guidelines and Standards for Oil and 

Gas Extraction (TDD) (DCN SGE01188). Specifically, this memorandum focuses on the tables 

and figures included in Chapter D.5 of the TDD, as listed in Table 1. TDD Tables and figures 

that are not listed in Table 1 either did not require calculations and/or analyses by ERG or are 

described in separate, supporting memoranda. The Crosswalk Memorandum between Proposed 

and Final Technical Development Document for Effluent Limitations Guidelines and Standards 

for Oil and Gas Extraction: Tables and Figures (DCN SGE01334) contains a crosswalk of all 

tables and figures in the TDD. Appendix F of the TDD contains the name of the relevant 

supporting memorandum for each TDD table and figure, where applicable. This memorandum is 

organized into the following sections:

 Section 1.0 describes underground injection well background;

 Section 2.0 describes the general methodology that ERG used to tabulate the data 

in Table D-2 and Table D-3 in the TDD (Chapter D, Section D.2);

 Section 3.0 describes the results of the analysis;

 Section 4.0 describes data quality and implications of key assumptions;

 Section 5.0 describes the quality assurance (QA) procedures that were followed 

throughout the analysis; and

 Section 6.0 lists all of the data sources used in the analysis.

For those figures/tables ERG generated specifically for this memorandum, the underlying 

data and analysis are contained in: 

 Attachment 1 contains the results of the analysis (DCN SGE01187.A01).

For definitions of common terms used throughout the TDD, the supporting memoranda, 

and memoranda attachments, please refer to the Glossary in the introduction of the TDD.
Analysis of Active Underground Injection for Disposal Wells Memorandum

June 7, 2016

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1.0 UNDERGROUND INJECTION WELL BACKGROUND

An injection well is a device that places fluid deep underground into porous rock 

formations (e.g., sandstone, limestone) or into or below the shallow soil layer. In its underground 

injection well control (UIC) program codified in 40 CFR Parts 144 to 148, EPA established six

classes of underground injection wells. These classes and their relationship to the unconventional 

oil and gas (UOG) industry are described in Section D.2 of the TDD. Class II wells are used to 

inject fluids associated with oil and natural gas production. The three types of Class II wells 

include:

 Hydrocarbon storage wells;

 Enhanced recovery wells; and

 Disposal wells.

Only enhanced recovery and disposal Class II wells are used to inject water. The use of 

enhanced recovery wells involves the injection of produced water, brine, salt water, water, steam, 

polymers, or carbon dioxide into oil-bearing formations to recover residual oil and—in some 

limited applications—natural gas.1Injected fluid can move through permeable formations to 

decrease the viscosity or displace small amounts of extractable oil and gas, which then becomes 

less resistant to flow and more available for production. In a typical enhanced recovery project, a 

single Class II enhanced recovery injection well is surrounded by multiple oil and gas production 

wells. These production wells bring oil and gas to the surface, often with large volumes of 

produced water (brine) from the formation (DCN SGE00132). Many enhanced recovery projects 

consist of a closed loop system in which produced water from the production wells is disposed of 

by injection into the adjacent Class II enhanced recovery well (DCN SGE00613; DCN

SGE00623; DCN SGE00132). According to communication with industry, this configuration is 

not possible in unconventional oil and gas formations because injected fluids cannot readily flow 

through the low permeability formation (DCN SGE00613).

The use of Class II disposal wells involves the injection of wastewater associated with oil 

and gas extraction for permanent disposal. 

One option for managing oil and gas extraction wastewater is transport to and injection

into a disposal well (DCN SGE00132). Class II disposal wells can dispose of fluids that are 

brought to the surface in connection with oil and gas production (e.g., conventional, CBM, 

UOG) and may be comingled with wastewater from gas plants, which are an integral part of 

production operations. The leading method of UOG extraction wastewater management

throughout the U.S. is injection into a Class II disposal well (DCN SGE001179). Furthermore, 

available literature and communication with industry indicates that UOG operators primarily use 

Class II disposal wells and typically do not use Class II enhanced recovery wells (DCN 

SGE00635; DCN SGE00276; DCN SGE00625).

 

1 The injection of fluids for hydraulic fracturing is also a form of enhanced recovery. See Legal Environmental 

Assistance Foundation v. EPA, 276 F.3d 1253 (11th Cir. 2001). However, Congress amended the Safe Drinking 

Water Act to exempt hydraulic fracturing (except where diesel fuels are used) from regulation under the UIC 

program (SDWA section 1421(d)(1)). Because there are currently no Class II permits for hydraulic fracturing 

activities, ERG did not consider wells that have been hydraulically fractured within the context of this 

memorandum.
Analysis of Active Underground Injection for Disposal Wells Memorandum

June 7, 2016

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2.0 GENERAL METHODOLOGY

Table D-2 in the TDD (DCN SGE01188) contains three types of data related to injection 

for disposal wells, on a state-by-state basis:

 Number of Active Disposal Wells

 Average Disposal Rate Per Well (gpd/well)

 State Disposal Rate (MGD)

ERG tabulated the number of active disposal wells and disposal rates because both of these 

parameters are needed to describe the availability of disposal wells. For example, two states (A 

and B) may have the same number of disposal wells, but if the average disposal rate per well2in 

state A is much less than that in state B, the total capacity of injection for disposal in state A will 

be less than state B. The following three subsections describe how ERG calculated and/or 

tabulated these three types of data for each state. Attachment 1 (DCN SGE01187.A01) contains 

the calculations and detailed documentation on a state-by-state basis. ERG made several 

assumptions throughout this analysis in order to present available data in a meaningful way for 

the TDD. Potential implications of these assumptions are described in Section 4.0.

2.1 Number of Active Disposal Wells

The Well Count Documentation tab in Attachment 1 (DCN SGE01187.A01) documents 

how ERG tabulated active Class II disposal wells on a state-by-state basis. For each state, this tab

includes:

 Number of active disposal wells (column G);

 Primary reference for well data (column B, “Agency/Organization”);

 Source for the active well count (column C, “DCN for Well Data”);

 Type of data source for the active well count (column D, “Type of Data Source”);

 Date that the data source was accessed and last updated (columns E and F, “Date 

ERG Downloaded” and “Date of Last Data Update”);

 Source of the data dictionary where relevant that was used to identify the meaning 

of each field in the raw data file (column H, “Data Dictionary Source”); and

 How ERG tabulated the number of active disposal wells using the data source 

(column I, “Filters to Tabulate Active Disposal Wells”).

Table 1 lists the four types of data sources ERG used to tabulate the active number of 

disposal wells by state. The order of the sources in Table 1 follows the general methodology 

ERG used to determine the number of disposal wells by state (explained in #1 through #3 

below). See the Well Count Documentation tab in Attachment 1 (DCN SGE01187.A01) for a 

description of the state-specific methodology.

1. For states where EPA maintains primary enforcement authority, ERG used data 

reported by EPA’s Office of Ground Water and Drinking Water (DCN 

SGE01012) titled Class II Disposal Inventory in EPA Direct Implementation 

Programs.

 

2 Reasons for low disposal rates can be due to characteristics of the geology or permit restrictions.
Analysis of Active Underground Injection for Disposal Wells Memorandum

June 7, 2016

Page 4

2. For states that have zero or minimal oil and gas production, ERG referenced a 

table published by EPA titled UIC Inventory by State – 2013 (DCN SGE01271). 

Most of these states have no active disposal wells.

3. For the remaining states, ERG searched for databases published by state oil and 

gas agencies. ERG conducted these searches in 2014, at which time many state 

databases contained well data for 2013 or 2014. ERG generally used the state oil 

and gas database if the data was last updated in 2013 or more recently. For states 

where the databases were last updated in 2012 or earlier, ERG instead referenced 

published reports that referenced state agency oil and gas databases.

Table 1. Summary of Data Sources for Active Disposal Well Counts

Type of Data Source Data Year

Number 

of States States

EPA OGWDW’s Class II Disposal 

Inventory in EPA Direct 

Implementation Programs (DCN 

SGE01012)

2014 11 AZ, FL, HI, IA, KY, MI, MN, NY, PA, TN, 

VA

EPA’s 2013 UIC Well Inventory (DCN 

SGE01271)

2013 16 CT, DE, GA, ID, MA, MD, ME, NC, NH, NJ, 

OR, RI, SC, VT, WA, WI

State oil and gas agency data Mostly 2013

and more 

recent

12 AK, AL, IL, KS, LA, MS, MO, MT, ND, NM, 

TX, OK

Published reportsa Mostly 2012 11 AR, CA, CO, IN, NE, NV, OH, SD, UT, WV, 

WY

Source: Well Count Documentation tab in Attachment 1 (DCN SGE01187.A01)

a—The primary published report ERG used was Veil Environmental, LLC’s 2015 report for the Ground Water 

Protection Council (GWPC) titled U.S. Produced Water Volumes and Management Practices in 2012 (DCN 

SGE01128), which contains summaries of 2012 disposal well data for all oil and gas producing states.3

As shown in Table 1, the years associated with available active disposal well count data 

ranged from 2012 to 2014.4 However, approximately 90 percent5of the active disposal wells 

ERG identified are based on 2012 and 2013 data. Although EPA proposed pretreatment 

standards for the Oil and Gas Extraction Category (40 CFR Part 435) on April 7, 2015 (80 FR 

18557), ERG did not update the active disposal well counts using more up-to-date state 

databases (i.e., 2015 data). This is because the most recent injection volume available (discussed 

in Section 2.2) represents 2012 data. Updating to more recent well counts would create a large 

difference between the count of active disposal wells and typical disposal rate presented in Table 

D-2. The following two subsections describe how ERG identified active disposal wells in state 

oil and gas databases and on tribal lands.

 

3 Veil Environmental, LLC’s 2015 report (DCN SGE01128) and the other available literature used for this analysis 

use the same definition of the term “oil and gas produced water” as is listed in this memorandum, where oil and gas 

produced water includes both flowback and long-term produced water. The report relied on state oil and gas 

agencies to estimate state level disposal well counts and volumes.

4A snap shot of active disposal well counts was obtained for individual states. Therefore, the data year for each state 

varied depending on the availability of data. 

5 ERG identified a total of 26,400 active disposal wells and 23,597 of them are based on 2012 or 2013 data (see the 

Summary of Results tab in Attachment 1 (DCN SGE01187.A01)).
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2.1.1 Accessing Databases

When accessing state and EPA OGWDW’s database (DCN SGE01012) to determine the 

number of active Class II disposal wells, ERG applied filters to the appropriate data fields in 

order to exclude inactive wells and wells that are not designated as disposal Class II wells. For

each well record, the databases contain fields such as API #, longitude, latitude, well status (e.g., 

active, plugged, shut in), and well type (e.g., oil, gas, enhanced recovery, disposal). The two 

primary data fields ERG used were well status and well type. ERG documented the specific 

filters applied for each state dataset within the Well Count Documentation tab. ERG included 

Class II disposal wells that were active or under construction. Specific acronyms for well status 

and type vary by state. ERG chose the necessary filters that represent the desired category of 

wells (i.e., active Class II disposal wells) based on the data dictionary for the state database, 

where available. Otherwise, ERG used engineering judgment to determine the appropriate filters. 

When available, ERG referenced data dictionaries published by state agencies to verify the 

appropriate filters. ERG specifically excluded inactive, plugged, permitted, proposed,

temporarily abandoned, and/or Class II enhanced recovery or hydrocarbon storage wells. 

2.1.2 Active Disposal Wells on Tribal Lands

ERG excluded wells on tribal lands reported by EPA OGWDW (DCN SGE01012) from 

the Summary of Results tab in Attachment 1 (DCN SGE01187.A01) because it was unclear if the 

state databases already contained them. Although EPA has primary enforcement authority for 

wells on all tribal lands except the Navajo Nation and Ft. Peck Reservation, it appears that some 

states may have included tribal wells in their datasets as well. For example, the state databases 

for New Mexico (DCN SGE00399), Wyoming (DCN SGE00405; DCN SGSE00406), and Utah 

(DCN SGE00403)6contain fields such as “Land Type” that are populated with “Indian” or 

“Tribal” for some wells. ERG summarized the number of active disposal wells on tribal lands 

separately in the Tribal Disposal Wells tab in Attachment 1 (DCN SGE01187.A01). ERG did not 

identify references that contain injection volume into disposal wells on tribal lands.

2.2 Average Disposal Rate per Well (gpd/well)

The Disposal Rate Documentation tab in Attachment 1 (DCN SGE01187.A01) 

documents how ERG calculated average disposal rates per well on a state-by-state basis. For 

each state, this tab includes the available disposal volume or rate data, the primary reference for 

the data (see column B, “Agency/Organization”; column C, “DCN for Volume Data”; and 

column D, “Type of Data Source”), the date that the reference was accessed and last updated, 

and how ERG estimated the average disposal rate per well using the data for this analysis.

ERG used the following procedure. See the Disposal Rate Documentation tab in 

Attachment 1 (DCN SGE01187.A01) for state-specific methodology.

1. First, ERG identified total annual volumes (barrels, bbl)

7

of produced water sent 

to disposal wells and the number of active disposal wells for the same data year in 

each state. Table 2 lists the four types of data sources ERG used to identify the 

 

6 ERG referenced Veil Environmental, LLC’s 2015 report for active disposal well counts for Wyoming and Utah. 

The underlying data used in Veil Environmental, LLC’s 2015 report are from the state oil and gas databases.

7 The oil and gas industry typically reports volumes in barrels (bbl), where 1 barrel is equivalent to 42 gallons.
Analysis of Active Underground Injection for Disposal Wells Memorandum

June 7, 2016

Page 6

total annual volumes of produced water sent to disposal wells. As shown in the 

table, all of the available data were either from 2012 or 2013.

2. For each state, ERG calculated the average disposal rate per well by dividing the

total annual volume (barrels) by 365 days/year and by the number of disposal 

wells active in the same year. ERG then multiplied by a conversion factor of 42

(gallons/barrel) to obtain the average disposal rate (gpd/well). The result is based 

on historical injection volume data8and is not related to the permitted or 

operational capacity of the well.9

Table 2. Summary of Data Sources Used for Disposal Rate Data

Type of Data Source

Data Year for 

Active Well 

Count

Number of 

States States

Veil Environmental, LLC’s 2015 

report titled U.S. Produced Water 

Volumes and Management 

Practices in 2012 (DCN 

SGE01128)a

2012 23 AL, AR, CA, CO, FL, IN, KS, KY, LA, MI, 

MO, MS, MT, ND, NE, NV, NY, OH, SD, 

TX, UT, WV, WY

Communication with EPA Region 3 2013 2 PA, VA

State oil and gas agency data 2012 or 2013 3 AK, NM, OK

No active disposal wells 2013 5 AZ, MD, MN, NC, TN

No data available N/A 1 IL

Source: Disposal Rate Documentation tab in Attachment 1 (DCN SGE01187.A01)

a—This report provides the total volume of oil and gas produced water sent to a specified number of active disposal 

wells in 2012.10

2.3 State Disposal Rate (MGD)

To provide context about how the availability of injection for disposal varies between

regions with UOG extraction11, for each state, ERG calculated the state disposal rate (MGD) 

using Equation 1.

Equation 1

State Disposal Rate (MGD) =

N (wells) × DRavg (

gpd

well)

1,000,000 gallons

MG

 

8 Typical average injection rates may vary for commercial and operator (private) Class II disposal wells, both of 

which are included in the well counts and injection volumes used to calculate the average disposal rate.

9 Capacity is a function of the salinity of the injected fluid, injection pressure permit limit (if applicable), and/or 

injection rate permit limit (if applicable) (DCN SGE00279).

10 Veil Environmental, LLC’s 2015 report (DCN SGE01128) and the other available literature used for this analysis 

use the same definition of the term “oil and gas produced water” as is listed in this memorandum, where oil and gas 

produced water includes both flowback and long-term produced water. The report also relied on state oil and gas 

agencies to estimate state level disposal well counts and volumes.

11 See Section D.2.3 in the TDD for more information about how the availability of Class II disposal wells affects 

the management of UOG extraction wastewater.
Analysis of Active Underground Injection for Disposal Wells Memorandum

June 7, 2016

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Where,

N = Number of active disposal wells identified using methodology in Section 2.1

DRavg = Average disposal rate per well (gpd/well) using methodology in Section 2.2

The Summary of Results tab in Attachment 1 (DCN SGE01187.A01) contains this 

calculation. As explained in Sections 2.1 and 2.2, respectively, the active disposal well counts

and disposal rates per well are both primarily based on 2012 or 2013 data. ERG used the most 

up-to-date data possible to estimate the state disposal rates (MGD) in Table D-2 of the TDD.

3.0 SUMMARY OF RESULTS

For each state, the Summary of Results tab in Attachment 1 (DCN SGE01187.A01) 

contains the number of active disposal well counts, average disposal rate per well (gpd/well), and 

state disposal rate (MGD). This tab contains all of the data presented in Table D-2 in the TDD. 

ERG excluded wells on tribal lands reported by EPA OGWDW (DCN SGE01012) from the 

Summary of Results tab in Attachment 1 (DCN SGE01187.A01) because it was unclear if the 

state databases already contained them. Instead, ERG summarized the number of active disposal 

wells on tribal lands separately in the Tribal Disposal Wells tab in Attachment 1 (DCN 

SGE01187.A01). This tab contains all of the data presented in Table D-3 in the TDD. No 

average disposal rate per well (gpd/well) or state disposal rate (MGD) data was available for 

wells on tribal lands.

The Summary of Results tab presents the results by state sorted by geographic regions as

assigned in the EIA Annual Energy Outlook report (DCN SGE01192). However, Texas and New 

Mexico are both split into two different geographical regions (i.e., Gulf Coast and Southwest) by 

EIA. Because ERG presents the results by state, ERG combined the EIA “Gulf Coast” and 

“Southwest” regions into one category for this analysis to keep state data for Texas and New 

Mexico together. For each region, ERG sorted the states by highest to lowest state disposal rate 

(MGD). Because ERG used different sources for active disposal well counts and average 

disposal rates, some states with active disposal wells have disposal rate data gaps. ERG sorted 

these states by highest to lowest count of active disposal well counts. 

4.0 DATA QUALITY AND ASSUMPTIONS

When assessing well databases for disposal well data, ERG did not substantiate 

individual well records within the underlying databases (e.g., well-by-well review). However, 

ERG did compare results of active number of disposal wells and injection volumes from this 

analysis to the references listed below and confirmed that they generally agree. As such, the 

datasets are considered sufficiently accurate to observe trends at the state, regional, and national 

levels.

 Veil Environmental, LLC’s 2015 report for the Ground Water Protection Council 

(GWPC) titled U.S. Produced Water Volumes and Management Practices in 2012

(DCN SGE01128)

 University of Oklahoma’s 2014 technical presentation: Class II Underground 

Injection Control Well Data for 2010–2013 by Geologic Zones of Completion, 

Oklahoma (DCN SGE01089)
Analysis of Active Underground Injection for Disposal Wells Memorandum

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 Test data from states working towards e-reporting in EPA’s OGWDW’s National 

UIC Database (not publicly available)

12

When referencing published reports for disposal well data, ERG was unable to 

substantiate individual well records because the published reports only contained summary 

statistics (e.g., total active disposal wells). However, ERG compared the number of active 

disposal wells and injection volumes from published reports to the references listed below and 

confirmed that they generally agree. For several states, ERG identified published report data that 

estimated a greater number of active disposal wells, which is potentially due to the inclusion of 

inactive or temporary abandoned wells in these published reports. For these states, ERG used the 

slightly more outdated reference instead of the published report data in an effort not to 

overestimate the number of active disposal wells. ERG identified these states in the Comments 

field in the Well Count Documentation tab in Attachment 1 (DCN SGE01187.A01).

 Corresponding state oil and gas databases

 Test data from states working towards e-reporting in EPA’s OGWDW’s National 

UIC Database (not publicly available)

As described in Section 2.0 and in the bullet points below, several assumptions were 

necessary to complete this analysis. These assumptions may increase or decrease the values 

presented in the TDD Table D-2 and are described below. As such, the results from this analysis 

should be used with careful consideration of their strengths and limitations.

 Calculation of the average disposal rate per well (gpd/well): ERG included all 

wells identified as active even if some of these wells reported zero injection 

volume. This assumption may decrease the average disposal rate per well but only 

affects states where ERG used state databases as the source for injection volumes 

(NM, AK, and OK). However, ERG excluded wells that were identified as just 

being drilled because they could not have injected any wastewater.

 Calculation of the state disposal rate (MGD): ERG included the number of 

disposal wells identified as currently being drilled (e.g., under construction) in the 

active number of disposal wells. This assumption may increase the current state 

injection rates but was intended to capture wells that will inevitably come online 

in the near future. However, ERG excluded wells from all calculations that were 

only permitted or proposed new well projects because these wells may be 

terminated even after they are permitted or proposed (i.e., may never come 

online).

 Missing volume data: ERG was unable to identify injected volumes for Illinois 

which has a substantial number of active disposal wells. Therefore, the total 

volume of produced water injected into disposal wells in the nation estimated by 

this analysis may be an underestimate. Illinois is highlighted red in the Summary 

 

12 EPA OGWDW is moving towards using an electronic reporting system for state primacy agencies, but it is not 

complete. A number of states have submitted some amount of data as they work to develop data flow, but most 

states with data are not final and there is a range of data quality. As there are known to be data gaps and the data is 

not approved by the state, it is not in the public record and is not used for official analyses.
Analysis of Active Underground Injection for Disposal Wells Memorandum

June 7, 2016

Page 9

of Results tab in Attachment 1 (DCN SGE01187.A01). Also, there is no available 

injection volume data for wells on tribal lands.

 Number of active disposal wells: As explained in Section 2.1, EPA OGWDW

reported approximately 900 active disposal wells on tribal lands in the nation all 

of which ERG summarized separately from wells reported by state agencies

because it was unclear if the state databases also contained these wells for some 

states. 

5.0 QUALITY CONTROL PROCEDURES

All of the analyses presented in this memorandum adhered to the Environmental 

Engineering Support for Clean Water Regulations Programmatic Quality Assurance Project 

Plan (PQAPP) (DCN SGE00957) and the Unconventional Oil and Gas (UOG) Supplemental 

Quality Assurance Project Plan (SQAPP) (DCN SGE00958), including collecting, evaluating, 

and analyzing existing data and information about underground injection disposal wells.

Specifically, ERG used the procedures described in Section 4 of the PQAPP to gather and 

manage existing data in support of the UOG rulemaking. ERG staff entered reference 

information for relevant sources into the UOG Literature Review database. The ERG index 

keeper reviewed all reference information, assigned each reference a Document Control Number 

(DCN), imported the reference information into the UOG Project File Index database, and saved 

referenced files in the Electronic Project File folder.

ERG also used the procedures described in Section 3 of the SQAPP when collecting 

existing data for use in the UOG rulemaking. ERG used a combination of sources, including 

reports, papers, and online databases from state regulatory agencies such as departments of 

environmental protection and oil and gas commissions. ERG assigned all references used in 

these analyses with one of the following source flags (DCN SGE00958):

 Source Flag A – Journal articles and documents prepared by or for a government 

agency (e.g., site visit reports, industry meeting notes); 

 Source Flag B – Documents prepared by a verified13 source that include citation 

information (e.g., operator reports, vendor documents, university publications); 

 Source Flag C – Documents prepared by a verified source that do not include 

citation information (e.g., operator reports, vendor documents, conference 

presentations); and 

 Source Flag D – Documents prepared by a source that could not be verified and 

that do not include citation information.

ERG followed the procedures described in Section 7.0 of the PQAPP to generate, 

evaluate, and analyze data using a spreadsheet. ERG conducted the following QA checks during 

the analyses:

 

13 ERG considered sources as “verified” if we were able to find information about the author outside of the reference 

document. ERG primarily verified information by looking for company/organization websites that confirmed the 

author’s affiliation with the UOG industry.
Analysis of Active Underground Injection for Disposal Wells Memorandum

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 ERG created the Injection for Disposal Well Data spreadsheet provided in 

Attachment 1 (DCN SGE01187.A01) to track relevant data and to document 

analyses. ERG performed a 100 percent check of all data entry, manipulations and 

calculations, and documented these in the internal version of the spreadsheet.

 For all analyses performed in state specific Access databases, one team member 

created queries and another team member reviewed the design and logic of the 

queries. ERG documented these checks in the internal version of the Injection for 

Disposal Well Data spreadsheet provided in Attachment 1 (DCN 

SGE01187.A01).

 ERG had a senior staff member familiar with ELGs and the UOG rulemaking 

review the results from the Injection for Disposal Well Data spreadsheet provided 

in Attachment 1 (DCN SGE01187.A01).

6.0 REFERENCES

Table 3 provides citations for references used in these analyses and their assigned source 

flag. 

Table 3. References

DCN State Full Citation Source Flaga

SGE00132 Multiple U.S. EPA. 2011. Underground Injection Control Program: Class II 

Wells—Oil and Gas Related Injection Wells (Class II). Available online 

at: https://www.epa.gov/uic/class-ii-oil-and-gas-related-injection-wells

A

SGE01271 Multiple US EPA. 2015. UIC Inventory by State in 2013. Office of Water. Office 

of Ground Water and Drinking Water. Underground Injection Control. A

SGE00276 N/A US EPA. 2012. Meeting with XTO Energy, Inc. about Unconventional 

Oil and Gas Sanitized. A

SGE00279 Multiple U.S. EPA. 2012. Meeting Summary: Conference Call with North Star 

Disposal, Inc. Regarding Underground Injection Operations in Ohio. 

(July 2).

A

SGE00383 KS Kansas Geological Survey (KGS). 2012. Kansas Wells. Downloaded on 

12/21/2012. Available online at: 

http://www.kgs.ku.edu/PRS/Ora_Archive/ks_wells.zip.

A

SGE00384 KS Kansas Geological Survey (KGS). 2004. Oil and Gas Well Database 

Abbreviations. Downloaded on 2/4/2013. Available online at: 

http://www.kgs.ku.edu/Magellan/Elog/status.html.

A

SGE00385 LA Louisiana Department of Natural Resources (LADNR). 2012. Produced 

Fluid Disposal Wells By Field. Office of Conservation. Downloaded on 

12/21/2012. Available online at: 

http://reports.dnr.state.la.us/reports/rwservlet?SRCN4282J_p.

A

SGE00386 LA Louisiana Department of Natural Resources (LADNR). 2012. UIC Well 

Class Type. Office of Conservation. Downloaded on 12/21/2012. 

Available online at: http://sonris.com/.

A

SGE00387 LA Louisiana Department of Natural Resources (LADNR). 2012. Status 

Code Description. Office of Conservation. Downloaded on 12/21/2012. 

Available online at: http://sonris.com/.

A
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Table 3. References

DCN State Full Citation Source Flaga

SGE00388 MO Missouri Department of Natural Resources (MODNR). 2012. Oil and 

Gas Permits. (December 19). Accessed on 12/21/2012. A

SGE00389 MT Montana Board of Oil and Gas Conservation (MTBOGC). 2012. UIC 

Wells. Accessed on 12/21/2012. A

SGE00391 ND North Dakota Industrial Commission (NDIC). 2013. Well Type 

Definitions. Department of Mineral Resources, Oil and Gas Division. 

Last Accessed on 2/4/2013. Available online at:

https://www.dmr.nd.gov/oilgas/codehelp.Asp.

A

SGE00392 ND North Dakota Industrial Commission (NDIC). 2013. Well Status 

Definitions. Department of Mineral Resources, Oil and Gas Division. 

Last Accessed on 2/4/2013. Available online at: 

https://www.dmr.nd.gov/oilgas/codehelp.Asp.

A

SGE00399 NM Petroleum Recovery Research Center (PRRC). 2012. All Wells Database. 

Downloaded on 2/4/2012. Available online at: 

http://octane.nmt.edu/gotech/Petroleum_Data/allwells.Aspx.

A

SGE00402 TX Texas Railroad Commission (TXRCC). 2012. Injection & Disposal 

Query Criteria. Accessed on 5/28/2013. Available online at: 

http://webapps2.rrc.state.tx.us/EWA/uicQueryAction.do.

A

SGE00403 UT Utah Department of Natural Resources (UTDNR). 2012. Well 

Information Search. Accessed on 2/4/2013. Available online at: 

http://oilgas.ogm.utah.gov/Data_Center/LiveData_Search/well_data_look

up.cfm.

A

SGE00405 WY Wyoming Oil and Gas Commission (WOGC). 2012. Well Header Data 

111412. Downloaded on 12/19/2012. Available online at: 

http://wogcc.state.wy.us/urecordsMenu.cfm?Skip=’Y’&oops=#oops#.

A

SGE00406 WY Wyoming Oil and Gas Commission (WOGC). 2013. Codes for Well 

Files. Downloaded on 2/4/2013. Available online at: 

http://wogcc.state.wy.us/codes.html.

A

SGE00526 AL Geological Survey of Alabama – State Oil and Gas Board (AL OGB). 

2013. Well Records Database. Accessed on 6/4/2013. A

SGE00537 CA Horsley Witten Group. 2011. California Class II Underground Injection 

Control Program Review. A

SGE00551 MS Mississippi Oil and Gas Board (MSOGB). 2013. Well Information 

Report Search. Accessed on 6/4/2013. A

SGE00557 ND North Dakota Industrial Commission (NDIC). 2014. Basic Subscription 

Services – Well Index. Department of Mineral Resources, Oil and Gas 

Division. Last Accessed on 1/27/2014.

A

SGE00613 N/A U.S. Environmental Protection Agency (U.S. EPA). 2013. Meeting with 

industry representatives about the unconventional oil and gas effluent 

guideline rulemaking. (February 28).

A

SGE00623 N/A U.S. Government Accountability Office (GAO). 2012. Energy-WaterNexus. Information on the Quantity, Quality, and Management of Water 

Produced During Oil and Gas Production. (January). GAO-12-156.

A

SGE00625 N/A US EPA. 2015. Site Visit Report Southwestern Energy Fayetteville Shale 

Operations. Sanitized. A

SGE00635 N/A US EPA. 2012. Site Visit Report Chesapeake Energy Corporation 

Marcellus Shale Gas Operations Sanitized. A
Analysis of Active Underground Injection for Disposal Wells Memorandum

June 7, 2016

Page 12

Table 3. References

DCN State Full Citation Source Flaga

SGE00770 IL Shutt, Doug. 2014. Email Correspondence between IL Office of Oil and 

Gas Resource Management and EPA. (May 30). A

SGE00957 NA Eastern Research Group, Inc. 2013. Environmental Engineering Support 

for Clean Water Regulations Programmatic Quality Assurance Project 

Plan (PQAPP). October 1. 

A

SGE00958 NA Eastern Research Group, Inc. 2014. Unconventional Oil and Gas (UOG) 

Supplemental Quality Assurance Project Plan (SQAPP). August 15. A

SGE00959 AK Alaska Oil and Gas Conservation Commission. 2014. AOGCC Data 

Extract Zip File. (April 8). A

SGE00960 AK Alaska Oil and Gas Conservation Commission. 2014. AOGCC Data 

Extract Zip File Table Description. (April 8). A

SGE01012 Multiple U.S. EPA. 2014. Class II Disposal Inventory in EPA Direct 

Implementation Programs. Data as of 3/31/2014. A

SGE01014 OK Oklahoma Corporation Commission (OCC). 2015. UIC Injection 

Volumes 2012. Downloaded on 2/5/2015. Available online at: 

http://www.occeweb.com/og/ogdatafiles2.htm.

A

SGE01015 OK Oklahoma Corporation Commission (OCC). 2014. Well_Status. 

Downloaded on 12/18/2014. Available online at: 

http://www.occeweb.com/og/ogdatafiles2.htm.

A

SGE01089 OK Murray, Kyle. 2014. Class II Underground Injection Control Well Data 

for 2010–2013 by Geologic Zones of Completion, Oklahoma. Oklahoma 

Geological Survey Open-File Report (OF1-2014). Norman, OK. Pp. 32.

A

SGE01109 PA/VA U.S. EPA. 2015. PA and VA Class II Injection for Disposal Volume 

Data. A

SGE01128 Multiple Veil, John. 2015. U.S. Produced Water Volumes and Management 

Practices in 2012. Veil Environmental, LLC. Prepared for Ground Water 

Protection Council (GWPC).

A

SGE01179 N/A ERG. 2016. Data Compilation Memorandum for the Technical 

Development Document (TDD). A

SGE01188 N/A U.S. EPA. 2016. Technical Development Document for Proposed 

Effluent Limitations Guidelines and Standards for Oil and Gas 

Extraction.

A

SGE01192 All U.S. Energy Information Administration. 2015. Annual Energy Outlook 

2015 with Projections to 2040. DOE/EIA-0383(2015). (April). A

SGE01334 N/A ERG. 2016. Memorandum Providing a Crosswalk between Tables and 

Figures in the Proposed and Final Technical Development Document for 

Effluent Limitations Guidelines and Standards for Oil and Gas 

Extraction.

A

a—Source Flag A—Journal articles and documents prepared by or for a government agency (e.g., site visit reports, 

industry meeting notes).

Source Flag B—Documents prepared by a verified source that include citation information (e.g., operator 

reports, vendor documents, university publications).

Source Flag C—Documents prepared by a verified source that do not include citation information (e.g., operator 

reports, vendor documents, conference presentations).

Source Flag D—Documents prepared by a source that could not be verified and that do not include citation 

information.
Analysis of Active Underground Injection for Disposal Wells Memorandum

June 7, 2016

Page 13

ATTACHMENT 1:

ANALYSIS EXCEL FILE (DCN SGE01187.A01)