Geologic Parameters Controlling Natural Gas Production from Single, Deeply Buried Coal Reservoir

David Decker

Methane occluded in coal reservoirs is being commercially produced in the Appalachian, Warrior, San Juan, and Piceance basins. Of these, the Piceance basin, with an estimated 100 tcf of coal-bed methane, represents the largest coal-bed methane resource in the United States. Exploration efforts applied to this vast resource have been hampered by lack of appropriate exploration, drilling, completion, stimulation, and production methods. The Deep Coal Seam Project sponsored by the Gas Research Institute and operated by Resource Enterprises, Inc., at the Red Mountain site, Mesa County, Colorado, was established to develop, improve, evaluate, and communicate the technology required to produce gas from deeply buried coal reservoirs.

Regional geologic studies have established the Red Mountain site as representing most of the coal-bed methane resource within the Piceance basin. The project is focused on the D coal seam, belonging to the Cameo coal group of the Williams Fork Formation, Upper Cretaceous Mesaverde Group. The D coal seam thickness ranges from 16 to 20 ft (5 to 6 m) throughout the site, with an average drilling depth of 5,500 ft (1,700 m). This coal seam is medium-volatile bituminous in rank, with an average gas content of 250 standard ft³/ton (8 standard cm³/g).

AAPG Search and Discovery Article #91043©1986 AAPG Annual Convention, Atlanta, Georgia, June 15-18, 1986.