GUY, WILLARD J., LYNN W. WATNEY, and RANDALL C. CARLSON, Kansas Geological Survey, Lawrence, KS

ABSTRACT: The Lansing-Kansas City (Upper Pennsylvanian) Limestone in the Hugoton Embayment (Western Kansas) - An Independent's Exploration Target

The Lansing-Kansas City cyclical limestone reservoirs (Missourian) in western Kansas continue to be an economic exploration and development target. The prospective area is primarily located beneath the Hugoton Gas field which produces gas from shallow Permian limestones, which also restricted deeper exploration until the late 1860's. The Lansing-Kansas City production was first established in 1823 on the Central Kansas Uplift and has become a very significant reservoir in the U. S. Mid-Continent area (600 million barrels +/-). Most of the production has occurred on the Central Kansas Uplift. The ten separate Lansing-Kansas City cyclic shallowing-upward grainstones vary from 2-40 feet in thickness at depths of 3000-5000 feet.

These extremely heterogeneous bioclastic and oolitic grainstone reservoirs have intergranular, intercrystalline, vugular, and oomoldic porosity with the latter being of greatest economic significance. The supreme challenge is to predict and evaluate the "effective porosity" in normally bimodal porous grainstones. Past exploration efforts concentrated on drilling subsurface anomalies with great success, but occasionally with great disappointments in finding an inadequate reservoir. Comprehensive statewide studies in the past few years by the Kansas Geological Survey have established some concepts and techniques which should decrease the risk in exploration and development of Lansing-Kansas City reservoirs. The concepts of sequence stratigraphy, sea-level changes, and compartmentalizati n must be considered. Individual cycles or sequences must not be individually studied, but rather in conjunction with the overlying end underlying sequences, since there is almost always a significant relationship between vertically stacked sequences. Using the combination of porosity-resistivity cross plots, bulk volume water, resistivity index, capillary properties, and resistivity gradients, a full understanding of the limestone reservoir is possible. Analysis of drill stem test pressure data can add to the reservoir characterization.

AAPG Search and Discovery Article #90987©1993 AAPG Annual Convention, New Orleans, Louisiana, April 25-28, 1993.