Exploration and Development History of Coalbed Methane on the Crow Reservation

This page was written by Erin Klauk as part of the DLESE Community Services Project: Integrating Research in Education. Funding was provided in part by the Montana Office of Public Instruction.

Map of US Coalbed Methane resources; click to enlarge. Details

Production of natural gas associated with coal beds accounts for about 7 percent of the total natural gas produced annually in the United States. Several important U.S. coal-bed gas-producing areas are in the Rocky Mountain region (i.e. Powder River Basin), where extensive shallow coal beds have produced or have the potential to produce coal-bed gas (Coal-Bed Gas Resources of the Rocky Mountain Region: National Assessment of Oil and Gas Fact Sheet (more info) ).

Although coalbed methane has a potential negative effect on the environment if not monitored and managed, if produced domestically, it reduces our need for import energy. Geologists are aware of the depositional environments that can produce coalbed methane, reducing the cost of extensive exploration. Also, methane is a relatively clean-burning source of energy, much cleaner than coal. Exploration costs for coal-bed methane are low, and the wells are cost effective to drill. Methane occurs in most coals, and the location of the Nation's coal resources is already well known (Coal-Bed Methane: Potential and Concerns (more info) ). These factors combine to make coalbed methane a locally-produced, affordable source of energy.

During coalification, large quantities of methane-rich gas are generated and stored within the coal on internal surfaces. Because coal has such a large internal surface area, it can store surprisingly large volumes of methane-rich gas; six or seven times as much gas as a conventional natural gas reservoir of equal rock volume can hold. In addition, much of the coal, and thus much of the methane, lies at shallow depths, making wells easy to drill and inexpensive to complete. With greater depth, increased pressure closes fractures in the coal, which reduces permeability and the ability of the gas to move through and out of the coal (Coal-Bed Methane: Potential and Concerns (more info) ).

A truck-mounted drill-rig in the Powder River Basin.
A truck-mounted drill-rig in the Powder River Basin. Details

To further investigate the exploration and development history of coalbed methane on the Crow Nation, follow the links below.

Investigate Resources Pertaining to Exploration and Development History of Coalbed Methane on the Crow Reservation

For ideas on how to use these webpages in a classroom, a Study Guide is provided.