U.S. Department of the Interior

U.S. Geological Survey

Fact Sheet 2006–3132

December 2006

U.S. Geological Survey and Bureau of Land Management 

Cooperative Coalbed Methane Project in the

Powder River Basin, Wyoming

Printed on recycled paper

Introduction

The Bureau of Land Management (BLM) 

Wyoming Reservoir Management Group and the 

U.S. Geological Survey (USGS) began a cooperative 

project in 1999 to collect technical and analytical 

data on coalbed methane (CBM) resources and 

quality of the water produced from coalbeds in 

the Wyoming part of the Powder River Basin. The 

agencies have complementary but divergent goals 

and these kinds of data are essential to accomplish 

their respective resource evaluation and management 

tasks. The project also addresses the general public 

need for information pertaining to Powder River 

Basin CBM resources and development.

BLM needs, which relate primarily to the 

management of CBM resources, include improved 

gas content and gas in-place estimates for reservoir 

characterization and resource/reserve assessment, 

evaluation, and utilization. USGS goals include 

a basinwide assessment of CBM resources, an 

improved understanding of the nature and origin of 

coalbed gases and formation waters, and the development of predictive models for the assessment of 

CBM resources that can be used for such purposes 

in other basins in the United States (for example, 

the Bighorn, Greater Green River, and Williston 

Basins) and in other countries throughout the world 

(for example, Indonesia, New Zealand, and the 

Philippines).

Samples of coal, produced water, and gas from 

coalbed methane drill holes throughout the Powder 

River Basin, many of which are adjacent to several 

active mine areas (figs. 1, 2), have been collected by 

personnel in the USGS, BLM Reservoir Management 

Group, and Casper and Buffalo BLM Field Offices. 

Sampling was done under confidentiality agreements with 29 participating CBM companies and 

operators. Analyses run on the samples include coal 

permeability, coal quality and chemistry, coal petrography and petrology, methane desorption and adsorption, produced-water chemistry, and gas composition 

MONTANA

WYOMING

ROSEBUD

BIG HORN

CUSTER

POWDER RIVER

CARTER

CAMPBELL

CONVERSE

WESTON

NIOBRARA

CROOK

JOHNSON

46°

44°

108° 106° 104°

Sheridan

Douglas

Crow Indian Reservation

Basin axis

S. DAKOTA

NATRONA

HARDING

BUTTE

BIG HORN

WASHAKIE

PLATTE GOSHEN

PRAIRIE

MUSSELLSHELL

YELLOWSTONE

FALL RIVER

DAWES

SIOUX

BOX

CARBON BUTTE

ALBANY

CUSTER

MEADE LAWRENCE

PENNINGTON

42°

SHERIDAN

Cities

Producing coalbed 

 methane wells 

Lower Fort Union and

 Lance Formations, 

 undivided

Wasatch Formation

Upper Fort Union 

 Formation

EXPLANATION

0 50 MILES

0 25 50 KILOMETERS

25

Syncline

N. Cheyenne

 Indian 

Reservation

TREASURE

MT ND

SD

WY

NE

ID

Powder

 River

Basin

NEBRASKA

Wright

Gillette

Figure 1.  Producing coalbed methane wells in the Wyoming part of the Powder

River Basin. Locations from Wyoming Oil and Gas Conservation Commission (2006).

and isotopes. The USGS has supplied results to the BLM Reservoir 

Management Group for their resource management needs, and data are 

released when the terms of the confidentiality agreements are completed 

and consent is obtained.
Samples from Coal Core

The Bureau of Land Management provides and maintains a wet lab (fig. 3) that is used for desorption of coal 

core at the well site. Core is collected and cut into 2-ft-long 

sections (fig. 4) and sealed in canisters for gas desorption. Information is recorded at the drill site to allow for 

calculation of the amount of gas lost from each of the core 

segments prior to being sealed in the canisters. The sealed 

canisters are placed in a temperature-controlled water 

bath (fig. 5) to simulate reservoir temperature of the coal 

at depth. Desorption readings are recorded at 15-minute 

intervals for the first nine hours (fig. 6), then are taken at 

progressively longer intervals until the time period between 

readings is long enough to allow for transport of the canisters to our USGS laboratory in Denver, Colo.

Coal samples are desorbed in the USGS laboratory 

until little or no gas is detected for an extended period of 

time. Gas and coal samples from selected wells are sent 

for isotopic analysis and high pressure methane adsorption 

analysis (respectively). Cores are sent to the USGS laboratory in Reston, Va. where they are described and analyzed 

for macerals. They are then provided to a contract laboratory for proximate, ultimate, and calorific analysis.

To date, samples have been obtained from 38 coalbed 

methane wells in the Wyoming part of the Powder River 

Basin (fig. 2). Desorption of gas and coal analyses were 

run on coal core from 838 canisters. Additionally, gas 

compositions and isotopes were determined for more than 

100 samples and adsorption isotherms were completed for 

73 samples.

Figure 2.  Locations of cored coalbed methane drill holes in the

Wyoming part of the Powder River Basin.

CONVERSE

FREMONT NATRONA

BIG HORN

NIOBRARA

WASHAKIE

HOT 

SPRINGS

PLATTE

WESTON

CROOK

CAMPBELL

SHERIDAN

JOHNSON

43°

44°

108° 107° 106° 105° 104°

45°

Core sample location

Township (north) and 

 range (west) 

Coal mine area

EXPLANATION

Powder River 

Basin

WYOMING

GOSHEN

T39

R68 R69 R67

R84 R83 R82 R81 R80 R79

R76 R75 R74 R73 R72 R71 R70 R66 R65 R64 R63 R62 R61

T57

T56

T54

T53

T52

T35

T37

T36

T38

T40

T41

T42

T43

T44

T45

T46

T47

T49

T50

T48

T51

T33

T34

R69 R68

T55 R78 R77 R76 R75 R74 R73 R72 R71 R70 R67

0 20 40 MILES

0 20 40 KILOMETERS

T39

R68

Figure 4.  Collection of coal core.

Figure 5.  Coal canisters in temperature-controlled

water bath.

Figure 3.  Bureau of Land Management Wyoming

Reservoir Management Group wet lab used for

methane desorption of coal core.

Figure 6. Measuring desorbed gas from the coal

canisters.
Produced Water from CBM Wells

Produced-water samples were obtained through 

tubing attached directly to CBM wellhead ports. Tubing 

was flushed thoroughly and samples were collected 

following the guidelines of Lico and others (1982). Field 

and laboratory measurements include pH, temperature, 

conductivity, alkalinity, dissolved oxygen, and ferrous/

total iron. Preserved samples were analyzed for major, 

minor, and trace cations and metals and for anions. 

Deuterium and oxygen isotopes were analyzed by an 

outside laboratory.

Sample analyses (table 1) indicate that CBMproduced water from the Paleocene Fort Union Formation 

is sodium bicarbonate-type water and has relatively low 

total dissolved solids (TDS) compared to most oil and 

gas production water, as well as to other CBM-produced 

water. Produced water from the Powder River Basin is 

reducing, which allows relatively high concentrations 

of redox-sensitive metals such as iron and manganese. 

Other trace metal concentrations, except for barium, are 

uniformly low. Low sulfate concentrations in almost all 

produced water in the Powder River Basin reflect the 

process of sulfate reduction, which allows for relatively 

high concentrations of barium compared to most ground 

water. CBM-produced water can have high sodium 

absorption ratios (SAR) because of the high sodium 

content relative to the low calcium and magnesium 

concentrations. High SARs may be an issue that must be 

addressed if surface disposal is an option. Other constituents in CBM-produced water, such as ammonia, may also 

be a concern for certain types of disposal options.

The composition of produced water in the Powder 

River Basin reflects the evolution of meteoric water 

subjected to geochemical processes and reactions along 

both horizontal and vertical flow paths. Compositional 

analyses of CBM-produced water exhibit areal trends for 

water from both individual coalbeds and for all coalbeds 

sampled from a given formation. Trends in TDS, SAR, 

and iron in produced water from coalbeds sampled from 

the Fort Union Formation and from the Eocene Wasatch 

Formation are shown in figure 7. These trends indicate 

that the composition of water from coalbeds in the Fort 

Union Formation is changing down long, regional flow 

paths rather than shorter, localized flow paths. Some 

horizontal and vertical variations in produced-water 

composition, however, indicate a more intricate interpretation that may be because of complex coal stratigraphy 

and (or) the possible misidentification of some of the 

coalbeds sampled. Additional analyses should clarify 

many of these relations.

Table 1.  Composition of produced water from coal in the Wasatch and Fort

Union Formations in the Wyoming part of the Powder River Basin compared

to the drinking water standard. (Note: Trends in total dissolved solids, sodium

absorption ratio, and iron are shown in fig. 7)

[SAR, sodium absorption ratio; TDS, total dissolved solids; NC, not calculated; NA, not 

applicable; *, recommendation only; mg/L, milligram per liter; and μg/L, microgram per liter]

Wasatch Formation

Produced Water 

(n=8)

Fort Union Formation 

Produced Water 

(n=174)

Drinking

Water

Standard

Range Average Range Average

pH 7.0–8.2 7.6 6.6–8.0 7.3 6.5–8.5* 

SAR 7–24 18 5.6–69 20 NA 

mg/L mg/L

TDS 530–3,010 1,420 270–2,800 1,050 500*

Chloride 3.4–24 14 5.1–130 14 250*

Sulfate 6.2–1,450 380 <0.03–530 5.4 250*

Bicarbonate 500–1,720 980 290–3,140 1,280 NA 

Calcium 6.0–74 25 1.8–78 29 NA 

Potassium 2.3–59 12 3.1–58 12 NA 

Magnesium 2.2–122 27 0.6–46 6 NA 

Sodium 210–730 440 110–1,100 430 NA 

Range Average Range Average

Pg/L Pg/L

Iron 24–850 330 20–17,500 1,720 300*

Manganese 5.9–68 25 1.4–350 34 50*

Arsenic <0.2–1.8 NC <0.2–4.1 NC 50 

Barium 90–320 170 14–2,710 730 2,000 

Cadmium <0.1 <0.1 <0.1 <0.1 5 

Chromium <1 <1 <0.1–8.8 NC 100 

Copper 0.28–0.97 0.53 0.11–2.9 NC 1,300 

Lead <0.5 <0.5 <0.1–0.43 NC 15 

Mercury <0.1 <0.1 <0.005–0.25 NC 2 

Selenium <1 <1 <2–8 NC 50 

Zinc <1–24 6.4 <1–80 NC 5,000*
Figure 7.  Areal distribution of total dissolved solids, sodium absorption ratio, and iron in produced-water samples from the Fort Union and

Wasatch Formations in the Powder River Basin.

0 50 MILES

MONTANA

WYOMING

0 –1.5

4.51–10

10.01–17.5

Iron

mg/L

MONTANA

WYOMING

1.51–4.5

MONTANA

WYOMING

The TDS in produced water in the 

Powder River Basin increase from 

the southeast to the west and 

northwest. The increase might reflect 

increased water/rock interaction 

along a hydrologic flow path away 

from areas of recharge. 

SAR

10.1–20

5.6–10

20.1–40

40.1–69

Fort

Union

Formation

Wasatch

Formation

TDS

mg/L

270 – 500

 501 –1,000

1,001 –1,500

1,501 –3,010

Total 

dissolved

solids (TDS)

Sodium

absorption

 ratio (SAR)

The SAR is a calculated value relating 

the amount of sodium to the amounts 

of calcium and magnesium in 

produced water. The SAR is an 

important consideration in relation to 

produced water disposal by land 

application or irrigation.

Concentrations of iron in produced 

water are relatively similar throughout 

the basin except for one group of 

samples in the middle of the basin.

The higher values for this group of 

samples might be a result of lithologic 

variation in coals in that area or depth.

0 50 KILOMETERS

25

25

EXPLANATION

Iron

Fort

Union

Formation

Wasatch

Formation

EXPLANATION

Fort

Union

Formation

Wasatch

Formation

EXPLANATION

CAMPBELL

JOHNSON

CONVERSE

SHERIDAN

CUSTER

ROSEBUD

BIG

HORN

POWDER

RIVER

CAMPBELL

JOHNSON

CONVERSE

SHERIDAN

CUSTER

ROSEBUD

BIG

HORN

POWDER

RIVER

CAMPBELL

JOHNSON

CONVERSE

SHERIDAN

CUSTER

ROSEBUD

BIG

HORN

POWDER

RIVER

Applications

Applications and benefits of data from this study are 

numerous. In addition to the use of the information generated 

to accomplish Federal CBM resource evaluation and management missions and to address public needs, the data are also 

synthesized and published by the USGS to benefit industry, 

academia, consultants, other Federal agencies, and State and 

local governments (see, for example, Flores, 2004; Stricker 

and others, 2006).

Some BLM applications of the data resulting from this 

study include (1) producing recoverable gas reserve estimates 

for resource management (Crockett and others, 2001), planning, and Environmental Impact Study; (2) estimating drainage 

and depletion of CBM resources (Crockett, 2004); (3) addressing and resolving issues between CBM development and coal 

mining that have resulted from the drainage of CBM resources; 

(4) ground-water modeling; (5) coal-reservoir analysis, 

characterization, and modeling; and (6) providing support of 

coal leasing and mine development in adjoining CBM leases 

(McGarry, 2005a–d).

The USGS uses the data to (1) perform coalbed gassaturation analysis (Stricker and Flores, 2002); (2) study the 

occurrence and distribution of economically minable coal; 

(3) determine the potential for CO2 sequestration using CO2

and CH4 adsorption-isotherm data (Stricker and Flores, 2003, 

2004); (4) define the extent, distribution, and character of 

coal reservoirs (McGarry and Flores, 2004); (5) determine the 

origin of CBM in the basin (for example, microbial studies 

by Klein and others, 2004, 2005; Stricker and others, 2006); 

(6) study the evolution of produced water; and (7) provide 

produced-water quality information to the public (Rice and 

others, 2000, 2002). This study has expanded into other basin 

areas in Wyoming and has resulted in additional studies in 

North Dakota and in other parts of the world as interest in, and 

the need for, additional CBM data has increased.
Acknowledgments

This study would not have been possible without the cooperation of many companies and operators in the Powder River Basin who 

allowed USGS and BLM workers to collect coal core, gas, and produced-water samples from their CBM wells (fig. 8). These companies 

include: Ammonite Energy Texas, Inc.; Anadarko Petroleum; Barrett Resources Corp.; Big Basin Petroleum; Bill Barrett Corp.; Conquest Energy; CMS Energy; Fidelity Company; Hi-Pro Production; Jacobs Ranch Coal Company; J.M. Huber Corporation; Kennecott 

Energy; Kennedy Oil; Lance Oil and Gas; Quantum Energy LLC; Marathon Oil; MichiWest Energy; Nance Petroleum; Ocean Energy; 

Pacific Minerals, Inc.; Peabody Natural Gas; Pennaco Energy; Redstone Gas Partners; Rim Operating Company; Thunder Basin Operating Company; Western Gas Resources; Williams Company; Williams Exploration and Production; and Yates Petroleum Corp.

Figure 8.  Drill site near Kaycee, Wyo. Bighorn Mountains in the background.

References Cited

Crockett, F., 2004, Review of drainage of Federal minerals 

due to coalbed natural gas development in the Powder River 

Basin: Bureau of Land Management, Wyoming Reservoir Management Group, Internal Study, Bureau of Land 

Management files, 1 p.

Crockett, F.J., Ellis, M.S., Stricker, G.D., Gunther, G.L., Ochs, 

A.M., and Flores, R.M., 2001, An Estimate of Coal Gas 

Resources in the Powder River Basin, Wyoming: Wyoming 

Geological Association 52nd Field Conference Guidebook 

2001—Wyoming Gas Resources and Technology, Extended 

Abstract, p. 183–189.

Flores, R.M., 2004, Coalbed methane in the Powder River 

Basin, Wyoming and Montana: An assessment of the 

Tertiary-Upper Cretaceous coalbed methane Total Petroleum System, in Total Petroleum System and Assessment of 

Coalbed Gas in the Powder River Basin Province, Wyoming 

and Montana: U.S. Geological Survey Digital Data Series 

DDS–69–C, version 1, chap. 2, 56 p.

Klein, D.A., Flores, R.M., McKinney S., Pereyra, L.P., and 

Pruden, A., 2005, Cultural and molecular studies of methanogens in Paleocene Fort Union Formation coal from the 

Powder River Basin of Wyoming and Montana: American 

Association of Petroleum Geologists 2005 Rocky Mountain Section–AAPG Jackson Hole Meeting, Jackson Hole, 

Wyoming, September 24–26, 2005, Meeting Program, 

p. 35–36.

Klein, D.A., Flores, R.M., Pereyra, L.P., and Pruden, A., 2004, 

Putative methanogen molecular evidence in Paleocene 

Fort Union coals in the Powder River Basin, Wyoming and 

Montana: Geological Society of America Annual Meeting, 

November 7–10, 2004, Denver, Colorado, Abstracts with 

Programs, v. 36, no. 5, p. 84.

Lico, M.S., Kharaka, Y.K., Carothers, W.W., and Wright, V.A., 

1982, Methods for collection and analysis of geopressured 

geothermal and oil field waters: U.S. Geological Survey 

Water Supply Paper 2194, 21 p.
McGarry, D.E., 2005a, Review of coalbed methane gas and 

conventional oil and gas resources, production, and economics, Bureau of Land Management, Wyoming Reservoir 

Management Group LBA Draft Environmental Impact Statements for the North Antelope-Rochelle mine area, 10 p.

McGarry, D.E., 2005b, Review of coalbed methane gas and 

conventional oil and gas resources, production, and economics, Bureau of Land Management, Wyoming Reservoir 

Management Group LBA Draft Environmental Impact Statements for the Buckskin mine area, 10 p.

McGarry, D.E., 2005c, Review of coalbed methane gas and 

conventional oil and gas resources, production, and economics, Bureau of Land Management, Wyoming Reservoir 

Management Group LBA Draft Environmental Impact Statements for the West Antelope mine area, 10 p.

McGarry, D.E., 2005d, Review of coalbed methane gas and 

conventional oil and gas resources, production, and economics, Bureau of Land Management, Wyoming Reservoir 

Management Group LBA Draft Environmental Impact Statements for the Maysdorf area (near Cordero-Rojo and Caballo 

Mines), 10 p.

McGarry, D.E., and Flores, R.M., 2004, Hydrodynamic and 

stratigraphic controls on Wyodak-Anderson coalbed natural 

gas reservoirs in the Fort Union Formation, Powder River 

Basin, Wyoming: AAPG Rocky Mountain Section MeetingRocky Mountain Natural Gas 2004, Denver, Colo. August 

9−11, 2004, website at http://www.mines.edu/Research/

PTTC/CBM/fortunion/index.html.

Rice, C.A., Bartos, T.T., and Ellis, M.S., 2002, Chemical and 

isotopic composition of water in the Fort Union and Wasatch 

Formations of the Powder River Basin, Wyoming and Montana: Implications for coalbed methane development: The 

Rocky Mountain Association of Geologists, Coalbed Methane of North America II, p. 53–70.

Rice, C.A., Ellis, M.S., and Bullock, J.H., Jr., 2000, Water coproduced with coalbed methane in the Powder River Basin, 

Wyoming: Preliminary compositional data: U.S. Geological 

Survey Open-File Report 00–372, 20 p.

Stricker, G.D., and Flores, R.M., 2002, Coalbed methane content in the Powder River Basin, Wyoming: Saturation by coal 

rank and depth: Nineteenth Annual International Pittsburgh 

Coal Conference Proceedings, Pittsburgh, Pennsylvania, 

September 22–27, 2002, Session 6, CD-ROM, 15 p.

Stricker, G.D., and Flores, R.M., 2003, Potential carbon dioxide sequestration and enhanced coalbed methane production 

in the Powder River and Williston Basins, in Sakkestad, 

B.A., ed., Proceedings of the 29th International Technical 

Conference on Coal Utilization and Fuel Systems, CD-ROM, 

p. 387–402.

Stricker, G.D., and Flores, R.M., 2004, Assessment of carbon 

dioxide sequestration in Fort Union coal beds in the northern 

Rocky Mountains–Great Plains coal basins: Geological

Society of America Annual Meeting, November 7–10, 2004, 

Denver, Colorado, Abstracts with Programs, v. 36, no. 5, 

p. 541.

Stricker, G.D., Flores, R.M., Klein, D.A., Rice, C.A., and 

Schmidt, R.A., 2006, Shallowest coalbed accumulation in the 

west: It’s all about water and microbes in the Powder River 

Basin: American Association of Petroleum Geologists, April 

9–12, 2006, Abstracts Volume, p. 102.

Stricker, G.D., Flores, R.M., McGarry, D.E., Stillwell, D.P., 

Hoppe, D.J., Stillwell, C.R., Ochs, A.M., Ellis, M.S., Osvald, 

K.S., Taylor, S.L., Thorvaldson, M.C., Trippi, M.H., Grose, 

S.D., Crockett, F.J., and Shariff, A.J., 2006, Gas desorption 

and adsorption isotherm studies of coals in the Powder River 

Basin and adjoining basins in Wyoming and North Dakota: 

U.S. Geological Survey Open-File Report 06–1174, 250 p.

Wyoming Oil and Gas Conservation Commission, 2006, website at http://wogcc.state.wy.us.

Additional Information

Links to additional publications that used data from this 

cooperative study are available on the USGS Central Energy 

Team website at http://energy.cr.usgs.gov/oilgas/cbmethane/

and on the Wyoming BLM website at http://www.wy.blm.gov/

minerals/og/ogcbm.htm.

Contacts

U.S. Geological Survey

Romeo M. Flores, Project Chief, U.S. Geological Survey 

Central Energy Resources Team, Denver, Colo., Phone: (303) 

236-7774, Email: rflores@usgs.gov

Gary D. Stricker, U.S. Geological Survey Central Energy 

Resources Team, Denver, Colo., Phone: (303) 236-7763

Cyndi A. Rice, U.S. Geological Survey Central Energy 

Resources Team, Denver, Colo., Phone: (303) 236-1989,

Email: crice@usgs.gov

Margaret S. Ellis, U.S. Geological Survey Central Energy 

Resources Team, Denver, Colo., Phone: (303) 236-7775,

Email: mellis@usgs.gov

Bureau of Land Management

Karl S. Osvald, Project Chief, Bureau Land Management 

Wyoming Reservoir Management Group, Casper, Wyo.,

Phone: (307) 261-7729, Email: Karl_Osvald@blm.gov

Dwain E. McGarry, Bureau of Land Management Wyoming 

Reservoir Management Group, Casper, Wyo., Phone: (307) 

261-7624, Email: Dwain_McGarry@blm.gov