COX, DAN, Consulting Geophysicist, Carthage, TX, and RON FOSHEE, Seagull Mid-South Inc., Shreveport, LA

ABSTRACT: Structural/Stratigraphic Reconstruction of Frontal "Choctaw" Triangle Zone Within Oklahoma Atoka Trend: Early Controls (Prethrusting) on Deposition of Deep-Water Clastic Reservoirs

A structural and stratigraphic study in southwestern Oklahoma, encompassing approximately 30 townships in Atoka, Coal, and Pittsburg counties, was done using several hundred wells, surface geologic maps, and more than 400 mi of 1980 seismic data. Isopach maps of six Atokan sands covered various areas, all within a deep-water fan setting. Structural balancing, done on numerous geologic cross sections of six mi or less, allowed correlation of logs of the various reservoirs and structural details within the frontal "Choctaw" triangle zone. Two regional cross sections were made based, respectively. on 12 and 16 mi of recent high-fold common-depth-point seismic lines, with a minimum of one-well-per-mile control, diameter data, and surface geology. These cross sections were reconstructed by line balancing to illustrate the amount of thrusting in the section and the pre-Pennsylvanian normal faulting that subtly controlled the Atoka sands depositional framework. The thickest and most channelized sands are found downthrown to these earlier faults, with this past relationship now obscured by post-Atokan thrusting.

AAPG Search and Discovery Article #90989©1993 GCAGS and Gulf Coast SEPM 43rd Annual Meeting, Shreveport, Louisiana, October 20-22, 1993.