ABSTRACT: Stratigraphic and Spatial Distribution of Some Upper Pennsylvanian Shales in South-Central Kansas as Related to Oil and Gas Production

Brian M. Allen, D. F. Merriam

Thick shale formations in the Upper Pennsylvanian section of south-central Kansas exhibit a predictable coarsening upward sequence. Lithologically the formations consist of mudstone, siltstone, and channel sandstone, with thin limestones and coal seams locally. These thick shale formations reflect an influx of detrital material, derived mostly from the south and east, and punctuate cyclic marine carbonate bundles. The shales are mainly marginal to nonmarine and exhibit regressive characteristics. Associated with these units downdip are shallow reservoirs that produce oil and gas, mostly from coarser clastic units. Information on the origin and distribution of the shales can be gained from noting thicknesses of specific facies within the formations and total thicknesses. B comparing stratigraphic properties from one unit to another it may be possible to obtain some insight into the geological history of the area and determine clues valuable for further exploration. Comparing the different properties of different units is done by noting the spatial coincidences and similarities of properties from unit to unit. This can be accomplished by pair-wise comparison, stacking and weighting, or combining maps and displaying the results as a coefficient of resemblance or a resultant map.

AAPG Search and Discovery Article #91003©1990 AAPG Annual Convention, San Francisco, California, June 3-6, 1990