Mississippian Combination Trap, Bindley Field, Hodgeman County, Kansas

Abstract

Bindley field, Hodgeman County, Kansas, is a combination paleogeomorphic and facies trap developed in lower Mississippian dolomite. Mapped originally as a simple domal anticline in an area of slightly thicker Mississippian section, this oil trap was found to be localized in a highly porous, low relief, bryozoan-mound facies of the Warsaw Formation. The reservoir facies was exhumed and given additional relief by at least two periods of erosion before final burial beneath Middle Pennsylvanian sediments. Paleontologic evidence indicates that beds of Salem age are present in the so-called Warsaw of the Bindley field area. Diagenesis drastically has modified original patterns of sediment texture. Early cementation of crinoid grainstones occluded porosity; dolomitization of muddy facies and dissolution of skeletal particles enhanced porosity; and silica replacement of evaporite and carbonate sediments further modified original sediment properties. Solution cavities and nontectonic fracturing are obvious results of subaerial weathering overprinted on other sediment features. Factors to be considered in future exploration for other oil traps in the subcropping trend of rocks of similar age in western Kansas are: (1) the difficulty of predicting areas of bryozoan-mound facies development, and (2) the fact that seismic-reflection mapping may not disclose the true vertical relief of the reservoir facies within the enclosing sedimentary rocks. Once production is established, complex reservoir behavior in fields of this type may be explicable in terms of details of reservoir lithology.