Depositional Facies of Hydrocarbon Reservoirs of Upper Cherokee Group, Anadarko Basin

James O. Puckette, Zuhair Al-Shaieb

The Desmoinesian upper Cherokee Group sequence in the Anadarko basin is the subsurface equivalent of the Cabaniss Group of eastern Oklahoma. This sequence includes the Pink limestone, Skinner sandstone, Verdigris limestone, and Prue sandstone intervals.

The upper Skinner sandstone, which has not been well documented, is an important hydrocarbon-producing reservoir in the Anadarko basin. The Skinner sandstone is represented by channel, delta-front-prodelta, and shallow marine facies. Channel facies consist of a primary elongate trend extending 40 mi southeast-northwest across Custer and Roger Mills Counties, Oklahoma. Several small secondary channels trending northeast-southwest were also observed. Active channel-fill sequences in the primary trend exceed 100 ft in thickness and represent the major producing reservoir of the upper Skinner sandstone. Delta-front-prodelta sequences are dominated by shale and interbedded sandstone-shale units. Shallow marine facies consist of massive coarsening-upward units that reach 300 ft in thickness This facies belt is broad and slightly elongated, approximately 12 mi wide by 20 mi long, and trends northeast-southwest somewhat normal to channel facies orientation.

Lithologically, the upper Skinner channel sandstone is feldspathic litharenite with abundant feldspar and quartz overgrowth. Both primary and secondary porosity were observed in the upper Skinner sandstone. Secondary porosity evolved mainly from dissolution of feldspar and lithic fragments. However, extensive cementation in the shallow marine facies has reduced porosity to negligible amounts and consequently reduced reservoir quality.

AAPG Search and Discovery Article #91025©1989 AAPG Midcontinent, Sept. 24-26, 1989, Oklahoma City, Oklahoma.