BRADY, LAWRENCE L., and WILLARD J. GUY
Kansas Geological Survey, Lawrence, Kansas

Abstract: Coal Resources and Coalbed Methane Potential in the Kansas Portion of the Forest City Basin

Within the Kansas portion of the Forest City basin is an estimated 16.4 billion tons (14.9 billion metric tons) of coal that is present deeper than 100 ft (30 m) below the surface. Of this amount, 14.3 billion tons (13.0 billion metric tons) is from coals within the Cherokee Group (Middle Pennsylvanian). These resource quantities were determined from 27 coal beds with 23 of the coals within the Cherokee Group. Resource amounts were determined for coals 14 inches (35 cm) or greater in thickness. Apparent rank of the coals is generally high-volatile B bituminous. Of primary concern for methane development is the generally thin [<2 ft (0.6 m)] occurrence of most coal beds in the basin.

A continuous core taken in east central Leavenworth County (S35, T9S, R22E) penetrated 13 coal beds within the depth interval from 721 to 1164 ft (220 - 355 m) for a total thickness of 11.5 ft (3.5 m) of coal. Within the Cherokee Group interval of 721-1130 ft (220-344 m) there are 11 coals present with a total coal thickness of 10.9 ft (3.3 m). The Riverton coal at 2.1 ft (64 cm) thick is the thickest coal in that core. Apparent rank of the Riverton coal is high-volatile B bituminous, and two samples show vitrinite reflectance values of Ro max=0.53 and 0.56.

Review of geophysical logs from areas of the Forest City basin in Kansas indicate that multiple coal beds are widespread throughout the basin, but are generally thin. Preliminary investigations indicate there are a few areas in the basin where the coal bed thickness exceeds 42 inches (107 cm). Additional study and exploration effort is needed to determine if economic quantities of coalbed methane exist in the basin.

AAPG Search and Discovery Article #90921©1999 AAPG Mid-Continent Section Meeting, Wichita, Kansas