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The AAPG/Datapages Combined Publications Database

Tulsa Geological Society

Abstract


Pennsylvanian Sandstones of the Mid-Continent, 1979
Pages 313-326

Channel Sandstone Oil Reservoirs of Pennsylvanian Age in Northwestern Ness County, Kansas

Robert F. Walters, Robert J. Gutru, Alfred James III

Abstract

Channel sandstones of Pennsylvanian (Desmoinesian, Cherokee) age are unusual oil reservoirs in Township 17 South, Range 24 West, Ness County, Kansas. A thickness map of the interval from an overlying marine marker, the Fort Scott Limestone, to the underlying Mississippian carbonate rocks depicts the topography of a former land surface now buried 4,400 ft deep. Where the mapped interval exceeds 125 ft, sandstone deposits fill incised paleovalleys.

The sandstones are interpreted as channel-fill sandstones because of (1) their position filling sinuous valleys; (2) their cross-section shape, convex base, and flat upper surface; (3) their dimensions - to 60 ft thick, frac14.gif (857 bytes) ml wide, and over 6 ml long; (4) the coarsening downward from very fine quartz grains to coarse sand and pea gravel at the base; (5) the enhanced permeability (over one darcy) near points of change of valley direction (point bar deposits?); (6) the common presence of 10° to 20° dips and cross-bedding in cores; and (7) the lateral gradational mixing of quartz sand with clastic chert fragments from residual cherts. Greenish clay is present in the upper fine-grained sandstones and glauconite in the lower coarse sandstones.

Six wells encountered isolated sandstone lenses (pressure decline on drill-stem tests) and produced only 7,148 bbls of oil per well before abandonment. One well is new. The other 28 wells produce oil from channel sandstone reservoirs with water drive. Over 100,000 bbls of oil per well (40-acre spacing) will be recovered from them. It is estimated that the 17 best wells (50% of the wells) will have an average gross ultimate production of 200,000 bbls per well of black paraffin base crude oil, gravity 35°.

Prospecting for channel sandstone oil reservoirs is hazardous with 49 dry holes surrounding the 35 channel sandstone oil wells. Discovery has been largely by chance while prospecting for oil in the Mississippian dolomites.


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