THE STATE OF PENNSYLVANIA'S COALBED METHANE RESOURCES

Interest in the economic value and development of natural gas from coal beds in Pennsylvania was stimulated by federal research during the late 1970s and early 1980s, resulting in a dramatic increase in production a decade later. Major growth in coalbed methane (CBM) as an unconventional source of natural gas continued from 1999 to 2008. This occurred in part because of increased knowledge of the CBM reservoir, improvement in drilling technology, higher gas prices, more favorable national economic conditions, and the need to expand domestic energy resources. Since then, the number of new well permits decreased in 2009 owing to the global recession and focus on the Middle Devonian Marcellus shale gas play. However, commercial quantities of CBM continue to be produced in the southwestern portion of the Main Bituminous field.

According to the Pennsylvania Department of Environmental Protection and the Pennsylvania Geological Survey Wells Information System, there are a total of 1,276 CBM wells in various stages of completion and status as of December 2013. The following coals of the Monongahela Group, Conemaugh Group, Allegheny Formation, and Pottsville Formation are among the principal CBM targets: Sewickley, Pittsburgh, Bakerstown (Upper and Lower), Brush Creek, Mahoning, Freeport (Upper and Lower), Kittanning (Upper, Middle, and Lower), Clarion, Brookville, and Mercer (Upper, Middle, and Lower). The most recent and complete annual production data compiled for 2012 reveals an all-time high figure of 16 billion cubic feet (Bcf). This could heat about 240,000 households for a year. Data for 2013 is currently under review.

Total CBM resource estimates were quantified by the following sources: (1) Geomega, Inc. (1983 unpublished report)–2,654 Bcf (2.7 trillion cubic feet [Tcf]) for Pennsylvania anthracite and bituminous coal; (2) Gas Research Institute (1988)–51 Tcf gas-in-place for southwestern Pennsylvania and northwestern West Virginia; and (3) United States Geological Survey (1996)–11.5 Tcf economically recoverable for the Northern Appalachian coal basin (Pennsylvania, Ohio, Maryland, and northern West Virginia). CBM, an energy source that rivals conventional natural gas in composition and heating value, continues to make a valuable contribution to our domestic energy mix on state and national levels.