**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 devel

opment 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 agree

ments with 29 participating CBM companies and operators. Analyses run on the samples include coal permeability, coal quality and chemistry, coal petrog

raphy and petrology, methane desorption and adsorp

tion, 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

B a s i n a x i s S. DAKOTA

NATRONA HARDING

BUTTE

BIG HORN

WASHAKIE

PLATTE GOSHEN PRAIRIEMUSSELLSHELL

YELLOWSTONE

FALL RIVER

DAWES

SIOUX

BOX BUTTE CARBON 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

KILOMETERS 50 0 25 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 main

tains 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 desorp

tion. 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 canis

ters 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 labora

tory in Reston, Va. where they are described and analyzed for macerals. They are then provided to a contract labora

tory 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 R79 R80 R81 R82 R83 R84

R73 R74 R75 R76 R70 R71 R72 R64 R65 R66 R61 R62 R63 T57

T56

T54
T53

T52

T35 T37

T36 T38 T40 T41 T42 T43 T44 T45 T46 T47 T49 T50

T48 T51

T33 T34 R68 R69 T55 R73 R74 R75 R76 R77 R78 R70 R71 R72 R67

20 40 MILES 0

40 KILOMETERS 0 20 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 constitu

ents 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 interpre

tation 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
**P** g/L **P** g/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
m g/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 50 1

– 1,000 1,00 1

– 1,500 1,50 1

– 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.

KILOMETERS 0 50 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 manage

ment 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), plan

ning, and Environmental Impact Study; (2) estimating drainage and depletion of CBM resources (Crockett, 2004); (3) address

ing 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 CO 2 

### sequestration using CO 2 

### and CH 4 

### 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.; Con

quest 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 Operat

ing 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 Reser

voir 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 Petro

leum 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., andPruden, 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 Moun

tain 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 eco

nomics, Bureau of Land Management, Wyoming Reservoir Management Group LBA Draft Environmental Impact State

ments 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 eco

nomics, Bureau of Land Management, Wyoming Reservoir Management Group LBA Draft Environmental Impact State

ments for the Buckskin mine area, 10 p.
McGarry, D.E., 2005c, Review of coalbed methane gas and conventional oil and gas resources, production, and eco

nomics, Bureau of Land Management, Wyoming Reservoir Management Group LBA Draft Environmental Impact State

ments 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 eco

nomics, Bureau of Land Management, Wyoming Reservoir Management Group LBA Draft Environmental Impact State

ments 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 RiverBasin, 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 Mon

tana: Implications for coalbed methane development: The Rocky Mountain Association of Geologists, Coalbed Meth

ane 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 con

tent 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 diox

ide 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, web

site at http://wogcc.state.wy.u s

.



# 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.ht m

.



# 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.go v 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.go v **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.go v