PETROPHYSICAL AND SEDIMENTOLOGICAL ANALYSIS OF RESERVOIR UNITS IN ELLIS CENTRAL KANSAS UPLIFT

The Central Kansas Uplift is the largest positive relief in the state of KS covering roughly 5,700 square miles. The uplift slices to the South through Kansas in a wedge shape, bounded to the west by the Hugoton embayment and the Anadarko basin and to the east by the Salina and Sedgwick basins. The timing of the Central Kansas Uplift has been roughly defined as a pre-Desmonesian to post Mississippian, structural feature that was largely completed by the Mesozoic. The basement rock is the stable Precambrian craton, which is an extension of the Canadian Shield. The composition of the basement rock transitions from rhyolitic in the north, to granitic in the south. Of great economic importance are the stores of oil and gas trapped in the uplift. The target intervals for petroleum exploration are located between 2000 to 3500 feet in depth within the sedimentary deposits. Characteristic facies include limestone, dolomite, and sandstone intervals. Limestone and dolomite comprise the majority of produced zones. The goal of this research is to characterize the petrophysical and sedimentary properties of the producing intervals. The objectives of this research are: generation of a facies map, characterize geochemical compositions, and estimation of possible hydrocarbon reserves. Three wells within a 7 mile radius were selected for this study. Well logs, cuttings, and geochemical data were used. Comparisons between well logs show similar log curve trends across all wells, indicating the same environment of deposition. Porosity averages 10-20% across the producing zones. Some of the highest porosities were seen in shale units which can be attributed to shale effect on the neutron log. Geochemistry data agrees with log responses, showing high amounts of clays consistent with shale layers, where logs indicate shales. Gamma ray log responses indicate zones consisting of shale layers interbedded with carbonate, dolomite, and siltstones. By combining geochemical and geophysical data to more thoroughly understand the nature of the reservoir, new wells can be placed with more certainty.