NEWELL, K. DAVID, Kansas Geological Survey, University of Kansas, Lawrence, KS, 66046-3736; and JOSEPH R. HATCH, United States Geological Survey, Denver, CO 80225-0046
Abstract: Petroleum Geology and Geochemistry of a Production Trend Along the McPherson Anticline in Central Kansas, with Implications for Long- and Short-Distance Oil Migration
The McPherson anticline trends NNE-SSW and traverses the arch between the Salina and Cherokee basins in Kansas. It extends 50 miles and contains 10 multi-pay oil and gas fields that produce from reservoirs in Paleozoic rocks. Subtle structural movement occurred throughout Paleozoic time, but the anticline is primarily a Late Mississippian - Early Pennsylvanian feature. It has a steeply dipping downto-the-west fault on its western flank that has up to 400 feet of throw. Culminations (and greater vertical offsets along the flanking fault) are generally adjacent to N-S-trending fault segments. Lesser vertical offsets along the flanking fault and structural sags are associated with NNE-SSW-trending fault segments. Reverse faulting is indicated by repeated stratigraphic sections encountered in wells, thus an overall right-lateral NNE-SSW wrench-fault regime can account for the distribution of structural traps.
The cross-fault juxtaposition of the Devonian-Mississippian Chattanooga Shale against a given pay zone may affect the chemical characteristics of the produced oils. Oils produced from Mississippian strata, relatively high in the section, have chemistries that suggest a mature Chattanooga Shale source rock and south-to-north migration up the crest of the anticline. Similarly, oils produced from pay zones in Ordovician rocks, where the Chattanooga Shale across the fault is shallower than the pay zone, are typical ?Ordovician? oils of low relative maturity. If, however, because of faulting, an Ordovician-age pay zone is located above or directly against the Chattanooga Shale, then oils produced from the Ordovician pay zone may have compositions indicating mixing of Chattanooga-Shale oils with ?Ordovician? oils.
AAPG Search and Discovery Article #90921©1999 AAPG Mid-Continent Section Meeting, Wichita, Kansas