Assessment of the Atoka Group of southwest Kansas as a Potential System

Abstract

The purpose of this thesis is to determine if the Atokan Series of Southwest Kansas represents a petroleum system. This thesis is focused on determining the source rock characteristics of the Atoka using stable carbon isotope, gas composition, Rock-Eval, and total organic carbon (TOC) analyses. Rock-Eval data indicate that the Atoka contains Type II and III kerogens that are oil prone. Atoka TOC values are greater than the minimum TOC content of 0.5 % required for hydrocarbon source rock classification. d13CCH4 values and vitrinite reflectance data indicate that Atoka rocks increase in maturity from south to north while depth of the Atoka decreases. This trend may reflect the preferential removal of overburden in the north following the Cretaceous. Within a given well, maturity increases with increasing depth. Overall, Atoka rocks have the potential to source overlying reservoirs and include a trend to the north of increasing gas-oil ratios.