MEMORANDUM

Date: January 10, 2008 

To: James Covington, III, U.S. EPA 

From: Anne Jones, ERG 

Subject: Compilation of Survey Universe Using HPDI, Inc., and State Data, with Summary 

Information (Update2) 

This memo presents the methods used to compile survey universe information along with summary data. 

ERG downloaded data from HPDI, Inc., and certain states, compiling these data in 20 separate databases, 

organized by state, due to the large size of some of the databases (HPDI data includes historic monthly 

production data for every well downloaded). A combined database that includes all states with commercial 

CBM development has also been prepared that provides the key well descriptor fields from HPDI (or 

equivalent state data) along with two fields created primarily from querying the HPDI production databases 

for the downloaded wells in each state (or, in some cases, using data obtained from state sources). These 

two fields provide 2006 total water and gas production data (where available) for each well in the combined 

database. 

Section 1 of this memo summarizes the general data collection/data cleaning approach to compiling the 

larger sets of databases. Section 2 discusses the specific details of specialized handling of data in certain 

states. Section 3 discusses the development of the more streamlined survey universe database that 

combines all of the state data collected by certain key data fields. Section 4 then presents several 

summaries of information extracted from the database. Section 4.1 summarizes the numbers of active 

wells/leases in the survey universe database by state and, within each state, by basin. Section 4.2 

summarizes the number of operators of active wells or leases in each state and basin. Section 4.3 presents

the 2006 production by state and basin represented in the database. 

1. Data Collection/Data Cleaning 

ERG licensed database information on historic well production from HPDI, Inc. (HPDI, 2007a). HPDI, 

Inc., compiles information from nearly all of the oil and gas producing states and provides detailed data in a 

consistent format to clients accessed through a web-based query system. For nearly all of the CBMproducing states, we collected the information by querying HPDI’s U.S. Historical Production Database. 

We entered the state and then selected both the CBM and COALBED METHANE flags. HPDI indicated 

that DOE provides information that helps HPDI create these flags (HPDI, 2007b), although the states often 

have their own flags in their data. This procedure, for the most part, generated all CBM well information 

available in the HPDI system, for all CBM wells in the HPDI system whether actively producing or not.1 

The states for which HPDI provided some or all of the survey universe data include: 

1) Alabama 

2) Arkansas 

3) Colorado 

4) Kentucky 

5) Kansas 

6) Louisiana 

7) Mississippi 

8) Montana 

9) New Mexico 

 

1

 HPDI, however, only maintains wells in their system for 5 years if no production activity has been 

reported, so this information is not useful for compiling a history of numbers of CBM wells ever producing. 
10) North Dakota 

11) Ohio 

12) Oklahoma 

13) Pennsylvania 

14) Texas 

15) Utah 

16) Virginia 

17) West Virginia 

18) Wyoming 

Of most importance to the EPA analysis, this information includes: 

• Well identification information (such as API number, lease name and number, well name and 

number, operator name, location, basin designation,2 field, and reservoir/producing formation), 

• Historic production information (including summary information on first production, last 

production, cumulative production, and last 12 months production as well as detailed information 

on year-by-year production),3

• Operator contact information (where available). 

The HPDI system allows easy downloading to a variety of database types. ERG chose MSAccess for 

managing the database, and downloaded all of the data available for each state, typically including both 

active and inactive wells. A total of 9 files were associated with each state’s download, although not all 

files contained data. At a minimum, these files contained the well descriptor information and the 

production information. 

The next step in constructing the survey universe databases was to identify the actively producing wells, 

since the files contained both active producers, as well as plugged and abandoned and other inactive wells 

or leases. There is a status flag (e.g., active/inactive) that can be used in the HPDI data queries. 

Conversations with HPDI indicated, however, that the states generally do not update status very frequently. 

We discussed the approach of using any reported production from 2007 as an “active” flag. HPDI 

confirmed that this is how they generally identify “active” wells when they report information. HPDI also 

indicated that some leeway for reporting lags needs to be made. A report of production any time during 

2007 probably allows sufficient leeway for reporting lags in most states (see below for exceptions to this) 

(HPDI, 2007b). Thus, the final databases have an active flag created by ERG based on (with a few 

exceptions) whether the well produced at some time during 2007. ERG has selected wells most likely to 

have been producing during the potential time frame of the analysis to define the survey universe, since 

active wells will always point to an actively producing CBM project, but inactive wells could point to 

entire projects that are no longer producing, which would not provide useful survey information. 

Following the identification of active wells, ERG determined that duplicate API numbers (generally 

indicating one well bore with more than one completion or a side track) were present in some instances. 

Some of these duplicates involved a completion that was currently active and a completion that was either 

flagged inactive or had been reporting 0 production for at least the last 12 months.4 ERG assumes that 

because one of the completions is active, the producer provides information for all completions, even if not 

producing. Thus, in some cases, the duplicates appear to indicate wells that were recompleted, with 

production from only the most recent completion. Because the active completion is effectively the 

 

2

 Basin definitions based on HPDI data are made on a county basis; there may be some discrepancies from 

geological definitions, if operators make this distinction. 

3

 Month-by-month production information can be accessed, but for EPA purposes, ERG considered yearby-year production data to be sufficient. 

4

 Where duplicates are not a concern, a well reporting 0 production is not considered inactive; short shutins are common due to a variety of factors, so this does not necessarily mean that the well or its economic 

unit are inactive. 
producing well from EPA’s perspective, only this completion is marked active and used in the universe 

database. Other duplicates are all active, particularly in the New Mexico portion of the San Juan Basin. 

These duplicates are kept in the main universe database, but are not counted as separate wells in reporting 

summary information. The production from the all completions is, however, summed into the 2006 

production data summary. 

Prior to or during the HPDI data acquisition, ERG also obtained data from some of the states. These data 

were used to augment, check on, or complete the data collection for the survey universe database. These 

activities are discussed further in Section 2. 

2. Data Compilation Issues By State 

The following sections present issues that we encountered in developing a state’s survey universe database, 

where issues arose. If no issues arose, and we used HPDI’s data as discussed in Section 1, no discussion is 

presented. 

Alabama 

Alabama recently updated their site to provide data on wells specifically flagged as CBM (previously, wells 

in the Pottsville Coal Interval could be called up to approximate wells considered CBM wells). These data 

included a number of wells that were newly permitted (after HPDI’s most recent acquisition of production 

data in May 2007). Of these, 15 were flagged as currently producing in the State’s status field (the 

remainder may be in the process of drilling or are permitted but not yet active). As these are new wells, it 

is assumed that the status report is up-to-date and that these producing wells should be added to the HPDI 

group, even though we have no actual production data at this time. 

Additionally, there are 12 actively producing wells that are found in the HPDI database that are not 

reported as CBM wells in the Alabama state data. One of these is clearly an offshore well, based on all 

data in the record, with the exception of the CBM flag. We deleted this record from the Alabama data. 

There were also 3 wells identified with production data that includes oil. CBM wells might be assigned 

liquids (oil or condensate) production at a point of sale, while not actually producing liquids. It is useful to 

note, however, that most of the state permits for CBM wells listed by the state are appended with a “-C” 

after the permit number. None of these wells has a “-C” permit number. We are keeping these wells in the 

database, however, unless the state confirms that if the permit does not have a “-C” designation, it is not a 

CBM well. Possible Action Item: Check with Alabama about whether the lack of a “-C” designation means 

that the well is clearly not a CBM well. 

Arkansas 

Arkansas data from HPDI are reasonably consistent with state data; the HDPI data appear to be newer than 

the state data. One operator, XTO operates a 2-completion well marked as CBM. This well is questionable, 

since it is in the middle of one of XTO’s major gas fields. The remaining CBM wells are all operated by 

CDX. The state data indicates only CDX as the active CBM producer in the state. DOE does not list the 

field, Cecil, as a CBM field in the Oil and Gas Field Master List. The record has not been deleted, however. 

Possible Action Item: Contact XTO to enquire about this well prior to sample selection. 

Kentucky 

None of the wells listed as CBM wells has produced in the last several years, according to HPDI data. 

Kentucky at this time is considered a state with no commercial production, but CBM development-ready. 

Other states such as this include Mississippi, North Dakota (see below), Oregon, and Alaska, among others 

that will be researched separately from this survey database effort. Surveying operators using the type of 

questionnaire currently under development that are involved strictly in noncommercial pilot operations or 

exploratory drilling will provide very little useful information, and a different approach for assessing 

impacts on newly developing regions is likely to be needed. Action Item: Contact with Kentucky (and 
other similar states) might be useful to determine the status of CBM development. Further direct contact 

with any identified operators undertaking exploration efforts may also be useful. 

Illinois 

Illinois data are not available from HPDI. ERG contacted the Illinois State Geological Survey, which 

prepares data at public request. The data do not include any current production information, but do include 

information on initial production. The contact at the Geological Survey provided a group of 442 wells that 

were flagged as coalbed methane related (Illinois State Geological Survey, Illinois_header_442.xls). The 

status code of CBM or CMM (coal mine methane) were identified as the key status codes (the other status 

codes generally indicated plugged, abandoned, unknown, coal test wells, vents, dry holes, and other 

unproductive wells, and a search for ever productive wells showed that only CBM, CMM, or plugged CBM 

or CMM wells were considered ever-productive, according to initial production numbers). ERG identified 

50 CBM or CMM wells that apparently were ever productive. To be conservative, however, 6 wells that 

were permitted and completed in 2007 were also considered potential producers, to account for reporting 

lags. Many of these 56 wells, however, may not have produced within the last year. Nineteen wells 

showing initial production, however, were permitted since 2000 and are likelier to be currently active. The 

Excel file was converted to Access and field names renamed to match the field names in the HPDI 

databases for inclusion in the combined survey universe database (permit date in this file was renamed 

completion date, since this was the only approximately equivalent date field in the HPDI database field 

names). 

Indiana 

Indiana well information is not available from HPDI. The Indiana Geological Survey website database 

(http://igs.indiana.edu/pdms) was queried, and all wells meeting query checks of “active” and “Penn. Coal 

Gas Wells” were downloaded (if “active” was not checked, 5 additional wells would have been 

downloaded). Production information by well is not available (production is only available on a field 

basis), but the data identifies the operator. This file, originally downloaded in Excel, was converted to 

Access and field names were renamed to match those in the HPDI databases for inclusion in the combined 

survey universe database. 

Louisiana 

HDPI data did not have a CBM flag available for Louisiana data. ARI, Inc., provided the name of an 

operator producing CBM, and they believed the operator was producing only CBM (Southwestern Energy 

Production Company) (ARI, 2007). This company was noted as having 10 active wells. These were all 

producing from the Reynolds Coals. Additionally, several other wells (17) were identified as producing 

from coals (Wilcox Coal or Wilcox Coals, in the data field “RESERVOIR”). These were added to the 10 

wells, for a total of 27 wells. This number roughly matched the number of CBM wells ARI recalled 

producing in Louisiana. 

Mississippi 

Mississippi shows no production for 3 wells listed as CBM wells. The status recorded in the database is 

drilling. 

North Dakota 

HPDI lists one well with inactive status in North Dakota. No production is reported for this well. 

Ohio 

Ohio reports only at the end of each calendar year, so active wells were identified in this state on the basis 

of reporting production as of 12/2006. The data appear similar to, but more complete than, data identified 

on a West Virginia site summarizing Appalachia Basin CBM development 
(http://ims.wvgs.wvnet.edu/website/pttc/viewer.htm) and an Ohio website database of oil and gas (which 

lacked the CBM flag at the time of downloading) (files can now be found at 

ftp://ftp.dnr.state.oh.us/Geological_Survey/POGO/. 

West Virginia 

Active wells were identified in West Virginia on the basis of merging data on CBM production in 2006 by 

operator and API number, 5 which were provided by WVDEP (Martin, 2007), into well identification data 

provided by HPDI, since HPDI had not yet obtained the 2006 data from West Virginia and the HPDI 

database does not have an adequate CBM flag. A total of 337 wells were found in the HPDI database, out 

of a total of 453 wells listed by the WVDEP as producing in 2006 (reduced to 449, once duplicate API 

numbers were accounted for). The 112 wells that were not found in the HPDI database are included in the 

merged database, although they have less complete information. Operator, 2006 production, and API 

number are all available, however. 

Virginia 

For Virginia, HPDI did not have a CBM flag. The Virginia Department of Mines, Minerals and Energy, 

Oil and Gas Division operate an online database from which several groupings of coalbed related wells can 

be flagged (http://www.dmme.virginia.gov/dgoinquiry/frmMain.aspx?ctl=1). The only two flags 

associated with any records were those for coalbed methane wells and coalbed methane wells with 

pipelines (others, such as for horizontal coalbed methane wells and dual completion gas/coalbed methane 

wells, had no records). ERG downloaded the data for all of the wells identified as “completed” CBM 

producing wells in the online database. Because this information did not indicate which wells were active, 

we then uploaded the API numbers for these wells into the HPDI database to identify the CBM wells 

within that database, using reported 2007 production to identify active wells. Out of 496 completions, 325 

wells were considered active given 2007 reported production. We then downloaded all HPDI information 

for these wells. We also downloaded all Virginia well and production information from HPDI because of 

our concern that there could be additional CBM wells in the state. CNX has many leases/wells named with 

CBM in the name that are not flagged as CBM in the Virginia database. We compiled a list of wells with 

either a well name or lease name with CBM somewhere within the name. If these wells are actually CBM 

wells, we would have a count of 1,606 active wells. One issue to note for Virginia is that a number of 

identified CBM wells have missing API numbers in the HPDI database. These wells can be identified by 

well names, however. Possible Action Item: Since we have a contact with CNX established through the 

Virginia site visit, it would be useful to ask our contact at CNX about the wells/leases with CBM in the 

name. It would also be useful to talk with the state about how they are flagging CBM, if these additional 

CNX wells are actually CBM wells. 

3. Compilation of Final Universe Database 

For ease of use, ERG compiled a smaller, more manageable database for use in survey stratification and 

sample selection, using only those data needed for possible stratification purposes. The database includes 

data from all states with active (2007) wells. Data fields used include state, basin, API number, field, 

reservoir, whether the information represented a well or lease, the lease number, the well name, the 

operator name, first production date, last 12 months of production of water and gas (Mcf), longitude, 

latitude, location (township-range) and 2006 production of water and gas (Mcf). 

 

5

 API number is a unique well identifier at the 10-digit level. It is composed of a 2 digit state identifier, a 

3-digit county identifier, and a 5-digit well identifier. Additional digits may also identify 

completion/production zones in an individual well bore. Where the state provides data on lease production 

only, the API number represents either the only well or one of the wells operating on that lease (HPDI, 

2007). 
4. Data Summary Information 

4.1. Counts of Active Wells or Leases 

Based on the work completed as discussed in Sections 1 through 3, Table 1 summarizes the numbers of 

active CBM wells or leases in each state, by basin. Note that in Kansas and Oklahoma, data are provided 

by the states only at the lease level; there may be more than one well on a lease in these states, so the total 

count of wells may understate wells due to this factor. 

States and basins are listed even if no active wells or leases were found if the wells/leases listed in the

HPDI database were classified as CBM wells. This has been done so that EPA might know where some 

exploratory activity is taking place or where more information gathering might be needed. These states 

were discussed briefly in Section 2. 

As the table shows, over 43,000 wells were active CBM producers in the U.S. as of mid-2007. 

4.2. Operators of Active Wells in Each State by Basin 

Using the databases developed as outlined in Sections 1 through 3, Table 2 presents a count of operators of 

actively producing CBM wells by state and basin. The total number of operators shown for each state and 

overall are not additive, since many operators operate CBM projects in several basins and states. Given the 

numbers of duplicates, the number of unique operators is expected to be approximately 400. 

4.3. 2006 Production by State and Basin 

ERG undertook a database query of the downloaded state databases determining the total 2006 production 

from all wells active in 2007. These results are shown in Table 3. Production data are not available for 

Indiana and Illinois; production data from Pennsylvania are from 2001. Total production for the active 

2007 wells totaled 1.77 trillion cubic feet (Tcf) in 2006. These figures show an increase over the reported 

2005 production of 1.73 Tcf (EIA, 2007), even before other 2006 production from wells not producing in 

2007 and the wells in states not reporting production is counted. 

References 

ARI, Inc., 2007. Meeting among ARI, ERG, and EPA to discuss CBM Survey effort, November 13. 

EIA, 2007. Energy Information Administration, 

http://tonto.eia.doe.gov/dnav/ng/ng_enr_cbm_a_EPG0_r52_Bcf_a.htm, downloaded December 11. 

HPDI, Inc., 2007. Data downloaded from HPDI’s U.S. Historic Production databases, October 18, 2007 

through November 17, 2007. 

HPDI, Inc., 2007b. Telephone call between ERG and HPDI helpline staff, October 25. 

Illinois State Geological Survey, 2007. Data provided to ERG as Excel file, named 

Illinois_header_442.xls. 

Martin, 2007. Email from James Martin, WVDEP, to Anne Jones, ERG, dated September 28. 
Table 1. Number of Active CBM Wells or Leases 

State Basin Number of Active 

Wells/Leases 

Black Warrior Basin 4,771 

Cahaba Basin 313 

Alabama 

Alabama/Florida/Mississippi Salt Dome Basin 6 

Arkansas Arkoma Basin 46 

Raton Basin 2,119 

San Juan Basin 1,736 

Uinta-Piceance Basin 137 

Colorado 

Green River Basin 7 

Illinois Illinois Basin 56 

Indiana Illinois Basin 85 

Cherokee/Forest City Basin 2,365* 

Anadarko Basin 2* 

Kansas 

Salina Basin 3* 

Kentucky Appalachian Basin 0 

Illinois Basin 0 

Louisiana Arkla Basin 27 

Mississippi Alabama/Florida/Mississippi Salt Dome Basin 0 

Montana Powder River Basin 877 

Sweetgrass Arch Basin 1 

New Mexico San Juan Basin 4,746 

Raton Basin 617 

North Dakota Williston Basin 0 

Ohio Appalachian Basin 22 

Oklahoma Arkoma Basin 1,373* 

Anadarko Basin 1,211* 

Pennsylvania Appalachian Basin 221 

Permian Basin 6 

Texas Gulf Coast Basin 2 

Texas 

Ft. Worth Basin 1 

Utah Uinta-Piceance Basin 831 

Virginia Appalachian Basin 324-1,606** 

West Virginia Appalachian Basin 449 

Powder River Basin 19,313 

Green River Basin 280 

Wind River Basin 20 

Wyoming 

Big Horn Basin 1 

Total (wells plus KS and OK leases) 43,250+ 

*Count of leases, not wells. 

**Virginia is presented as a range because of the issues discussed in Section 2. 

+Includes 1,606 Virginia wells. 

Source: Survey universe database compiled using HPDI, Inc., and some state data. 
Table 2. Count of Operators by State and Basin 

State Basin Number of Active Operators 

Black Warrior Basin 14 

Cahaba Basin 2 

Alabama/Florida/Mississippi Salt Dome Basin 2 

Alabama 

All Basins 18 

Arkansas Arkoma Basin 2 

Raton Basin 8 

San Juan Basin 20 

Uinta-Piceance Basin 13 

Green River Basin 3 

Colorado 

All Basins 35 

Illinois Illinois Basin 11 

Indiana Illinois Basin 10 

Cherokee/Forest City Basin 49 

Anadarko Basin 2 

Salina Basin 3 

Kansas 

All Basins 54 

Appalachian Basin 0 

Illinois Basin 0 

Kentucky 

All Basins 0 

Louisiana Arkla 4 

Mississippi Alabama/Florida/Mississippi Salt Dome Basin 0 

Powder River Basin 3 

Sweetgrass Arch Basin 1 

Montana 

All Basins 4 

San Juan Basin 57 

Raton Basin 2 

New Mexico 

All Basins 59 

North Dakota Williston Basin 0 

Ohio Appalachian Basin 2 

Arkoma Basin 53 

Anadarko Basin 67 

Oklahoma 

All Basins 111 

Pennsylvania Appalachian Basin 12 

Permian Basin 1 

Texas Gulf Coast Basin 1 

Ft. Worth Basin 1 

Texas 

All Basins 2 

Utah Uinta-Piceance Basin 8 

Virginia Appalachian Basin 4 

West Virginia Appalachian Basin 18 

Powder River Basin 79 

Green River Basin 17 

Wind River Basin 6 

Big Horn Basin 1 

Wyoming 

All Basins 103 

Total* 457 

*Total reflects many possible duplicate operators across multiple states. 

Source: Survey universe database compiled using HPDI, Inc., and some state data. 
Table 3. 2006 Production from All Wells Active in 2007 by State and Basin. 

State Basin 

Total Annual 2006 

Production (MMcf) 

Black Warrior Basin 113,235 

Cahaba Basin 2,755 

Alabama 

Alabama/Florida/Mississippi Salt Dome Basin 7 

Arkansas Arkoma Basin 2,454 

Raton Basin 95,256 

San Juan Basin 413,309 

Uinta-Piceance Basin 5,393 

Colorado 

Green River Basin 2 

Illinois Illinois Basin NA 

Indiana Illinois Basin NA 

Louisiana Arkla 138 

Cherokee/Forest City Basin 23,503 

Anadarko Basin 32 

Kansas 

Salina Basin 45 

Kentucky Appalachian Basin 0 

Illinois Basin 0 

Mississippi Alabama/Florida/Mississippi Salt Dome Basin 0 

Montana Powder River Basin 11,712 

Sweetgrass Arch Basin 17 

New Mexico San Juan Basin 505,516 

Raton Basin 26,399 

North Dakota Williston Basin 0 

Ohio Appalachian Basin 322 

Oklahoma Arkoma Basin 36,398 

Anadarko Basin 11,203 

Pennsylvania Appalachian Basin NA 

Permian Basin 169 

Texas Gulf Coast Basin 5 

Texas 

Ft. Worth Basin 14 

Utah Uinta-Piceance Basin 76,664 

Virginia Appalachian Basin 34,004 

West Virginia Appalachian Basin 19,020 

Powder River Basin 374,090 

Green River Basin 14,026 

Wind River Basin 1,856 

Wyoming 

Big Horn Basin 19 

Total 1,768,794

Source: Survey universe database compiled using HPDI, Inc., and some state data. 

Note: This does not represent all CBM production in 2006. Some production is not reported because of 

wells producing in 2006 that did not produce in 2007. Additionally, 2006 production data are not available 

from Pennsylvania, Illinois, and Indiana. Virginia production reflects the 1,606 well-count figure.