(1) Atoka Coal Labs, Englewood, CO
ABSTRACT: Regional Gas Content and Permeability Trends for the Coals in the Interior Basin, USA
The Interior Basin is a term used for the extensive deltaic deposition and subsequent development of widespread coal deposits during Middle and Upper Pennsylvanian times and that would eventually become the Arkoma, Forest City, Cherokee and Illinois Basins of present day. The coal seams are generally high volatile bituminous C through A, 0.3 to 2 meters thick, and have large lateral extent. Coal bed methane activity continues at a frantic pace in the Arkoma and Cherokee Basins but has slowed or stalled considerably in the Forest City and Illinois Basins. A number of test wells, pilot projects and development drilling by industry and state organizations over the past two years have begun to characterize the coals and shales of the Interior Basin. The present four basins comprising the Interior Basin have undergone different tectonic history which has inherently controlled gas contents and permeability of the coals. Episodic periods of degassing, influx of meteoric waters and migration of low temperature hydrothermal fluids has further either enhanced or reduced permeability and gas content of the coal seams. Within the four basins only some of the coals seem to contain recoverable whereas others do not. In addition, there is in most of the Interior Basin fully saturated or over saturated black shales that have not seem to been as readily degassed as the coals. Shale gas represents a potentially overlooked resource. By integrating the various data sets a more definitive set of models can be constructed upon where to explore for coal bed methane and shale gas in the Interior Basin.
AAPG Search and Discovery Article #90026©2004 AAPG Annual Meeting, Dallas, Texas, April 18-21, 2004.