U.S. Department of the Interior

U.S. Geological Survey

Fact Sheet 2006–3137

November 2006

Coalbed Methane Extraction and Soil Suitability Concerns 

in the Powder River Basin, Montana and Wyoming

Printed on recycled paper

The Powder River Basin and 

Coalbed Methane

The Powder River Basin is located 

in northeastern Wyoming and 

southeastern Montana. It is an area 

of approximately 55,000 km2 that 

is underlain by many coal seams. 

The basin extends over 400 km from 

Douglas, Wyoming, in the south 

to Forsyth, Montana, in the north 

(fig. 1). Extraction of methane gas 

from the coal seams that underlie the 

Powder River Basin began in Wyoming in the late 1980s and in Montana in the late 1990s.

Methane gas accumulates naturally within coal beds. Water in the 

coal beds provides the necessary 

pressure to keep the gas confined 

within the coal. Hydrostatic pressure 

from the water (called “co-produced 

water”) must be reduced before gas 

can be brought to the surface. Management of co-produced water is a 

concern because of the large volumes 

of water involved and because of the 

composition of the water.

Water Management Strategies

About 100–200 barrels of coproduced water per day are being 

extracted from each active well in the 

Powder River Basin, which comes 

to over 1.5 million barrels of water 

per day for all the active coalbed 

methane wells in the Basin. Lab 

testing indicates that Powder River 

Basin co-produced water is potable 

but is high in sodium and other salts, 

especially in the western and northern parts of the Powder River Basin. 

Common water management strategies 

include discharge into drainages, stock 

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Figure 1.  The outline of the Powder River Basin of Wyoming and Montana is shown on a

color shaded relief map of the region. The blue outlines indicate locations of hyperspectral

remote sensing data acquired by the Rocky Mountain Geographic Science Center.
Figure 2.  Center-pivot irrigation activity near Beaver Creek, Powder

River Basin, Wyoming.

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Figure 3.  Relative energy reflected by the swelling clay montmorillonite. Taken from R.N. Clark, G.A. Swayze, R. Wise, K.E. Livo, T.M. Hoefen,

R.F. Kokaly, and S.J. Sutley, USGS Digital Spectral Library splib05a,

USGS Open File Report 03–395, 2003.

ponds, evaporation ponds, or infiltration ponds; treatment 

to remove sodium; or application of the water directly 

on the land surface via irrigation equipment or atomizers 

(fig. 2). Re-injecting the co-produced water back into 

the ground is a less common water management strategy 

because it requires locating a geologic unit with enough 

capacity to store the water.

Geographic Science Focus—Use of Remote Sensing 

Technology to Locate Areas Unsuitable for the Land 

Application Water Management Strategy

The direct land application water management strategy 

employed by some well operators involves using irrigation equipment or atomizers to spray co-produced water 

on the ground, in some cases in an attempt to grow crops 

(fig. 2). Problems may arise because much of the Powder 

River Basin contains soils with high amounts of swelling clays. Swelling clays are clays that expand when wet. 

Soils dominated by these clays can turn to hard pan if 

irrigated with water high in sodium, such as that extracted 

from coal seams in the Powder River Basin. Applying 

high-sodium water directly on an area composed of swelling clays will cause the ground surface to become almost 

impermeable to rain or irrigation water, thereby destroying any salt-intolerant vegetation in the area. Resource 

and land managers need data on the suitability of soils in 

the Powder River Basin, including the location of surficial 

swelling clays, to help them determine whether to permit 

the direct application of sodium-dominated co-produced 

water.

As part of the USGS Rocky Mountain Geographic 

Science Center’s hyperspectral research program, 

researchers are investigating whether hyperspectral remote 

sensing data can be beneficial in locating areas of swelling 

clays. Materials on the Earth’s surface reflect, absorb, and 

transmit solar radiation differently. Hyperspectral sensors have the ability to measure this energy across a broad 

spectral range that includes non-visible portions of the 

spectrum. We can identify materials on the Earth’s surface 

by their signature of reflection or absorption at different 

wavelengths. Figure 3 shows the reflectance signature of 

the swelling clay montmorillonite.

Using detailed hyperspectral data collected over parts 

of the Powder River Basin (figs. 1 and 4) and applying our 

knowledge of how the clays of interest reflect energy, we 

will attempt to identify and map areas of swelling clays. 

If successful, such information will be useful to resource 

and land managers. 
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Figure 4.  Color infrared image generated from the southern part of a hyperspectral flight line near Decker, Montana,

overlaid on a black and white Digital Orthophoto Quadrangle. This area in southeastern Montana is an area of coalbed

methane (CBM) activity. Yellow symbols indicate the locations of active coalbed methane wells in the area as of November 2005. Red areas on the color infrared image indicate healthy vegetation. Monitoring of vegetation surrounding CBM

wells could provide resource and land managers early indications of problems caused by application of co-produced

water. See figure 1 for the entire extent of this flight line.

Contact:

Jamie L. McBeth

U.S. Geological Survey

Rocky Mountain Geographic Science Center

P.O. Box 173492

Montana State University, 229 AJM Johnson Hall

Bozeman, MT 59717

e-mail: jlmcbeth@usgs.gov