Columbia Gas and the Gas Research Institute are studying a set of Devonian shale gas wells in southwestern West Virginia to determine the geologic controls on shale gas production. Approximately 25 line-mi of Vibroseis seismic data were recorded to (1) evaluate the regional geologic setting and structural style of the area; (2) evaluate relationships among the regional geology, a high producing shale gas area, and a postulated fault zone; (3) evaluate the local geologic setting of three study wells; and (4) attempt to recognize stratigraphic controls on shale gas production.

Several initial conclusions concerning production controls have been reached. (1) Basement faulting extended up through the shale section, and resultant fracturing influenced gas production in the northern area of the seismic survey. (2) Reflection patterns in the shale contain information on the lithologic character of the shale. Local lenses of silt or sandy shale are probably present within the more fine-grained shale section. These lenses may be geologic features with increased permeability. (3) Areas of dimmed reflection energy on seismic lines correlate with areas of high gas reserves, suggesting that these areas are fractured shale.

Information from the seismic survey is being integrated with core, log, and well-test data to understand the active controls on shale gas production in the study area.

End_of_Article - Last_Page 1439------------