ABSTRACT: Analysis of Carbonate and Siliciclastic Strata at a Depositional Shelf Edge Utilizing High-Resolution Reflection Seismic Imaging, Pennsylvanian, SE Kansas

FELDMAN, HOWARD R., EVAN K. FRANSEEN, RICHARD D. MILLER, and NEIL L. ANDERSON, Kansas Geological Survey, Lawrence, KS

The Drum Limestone (Kansas City Group) in outcrop and in the shallow subsurface of southeastern Kansas contains an oolite facies that is potentially analogous to petroleum reservoirs in central and western Kansas. Outcrop, core, and high-resolution seismic data have been integrated to characterize and better understand the depositional history of the Drum oolite and associated strata. The oolite was deposited along the seaward edge of a shale delta. Overlying the delta plain, the Drum in a 3-20 ft thick stromatolitic mudstone and oolitic grainstone. As the underlying delta thins basinward, the oolite thickens abruptly up to as much as 75 ft thick. In a continued basinward direction the Drum thins and pinches out. This entire transition occurs over a distance of as little as 0.75 mi.

Geophysical logs and cores along two transects chosen for high resolution seismic surveys indicate significant elevation and geometric changes in the Drum Limestone (at about 200 ft depth). A 12-fold CDP line was designed to determine the feasibility and practical resolution limits of the CDP method. With a dominant frequency in excess of 180 Hz the predicted resolution limit at this site, using the 1/4-wavelength criterion, is approximately 6 ft. Practical resolution is closer to 4 ft. Two subparallel 48-fold CDP lines (offset by 0.5 mi) acquired using a split-spread geometry imaged geometric changes in the Drum oolite and overlying channelized sandstones. High-resolution seismic reflection imaging provides critical data for determining stratigraphic relationships crucial to understa ding the origin of the oolite.

AAPG Search and Discovery Article #91012©1992 AAPG Annual Meeting, Calgary, Alberta, Canada, June 22-25, 1992 (2009)