A detailed geological understanding of the reservoir combined with reservoir simulation to test the reservoir description and determine optimum recovery method is important for successful operation of mature fields. This South Slattery field case study demonstrates how a geologist using sequence stratigraphic concepts and moderately priced software can develop a reservoir model that can be analyzed by an engineer using a reservoir simulator affordable by independent operators. The full-length paper presents the method of geologic characterization in the Slattery field, a description of the input data needed for simulation, the history matching process, and results of the simulation to determine optimum recovery techniques.