The Economic Potential of Strategic Infill Drilling in the San Andres/Grayburg South Central Basin Platform Play

ABSTRACT This paper summarizes the results of a larger study assessing the economic potential of extensive infill drilling in the San Andres/Grayburg, South Central Basin Platform Play.1 The study provides estimates of economically recoverable crude oil and associated gas from infill drilling in 19 West Texas carbonate fields contained in the play. A detailed geologic and engineering analysis was conducted on a specific 640-acre section of the Dune Field (Section 15), which was considered to be representative of the fields in the play and was used for evaluating the potential infill recovery in the analyzed reservoirs. Estimates of recoverable oil and associated gas were contrasted for reductions in well spacing from 80 acres to 10 acres per well, using a uniform or "blanket" infill drilling program compared to a geologically targeted, "strategic" infill drilling program. The results indicate that, due to reservoir heterogeneity, significant volumes of oil and gas are economically recoverable through extensive infill development in the play. Geologically targeted drilling significantly improves project economics and dramatically lowers the threshold oil price required to support project implementation. The results indicate that cost-effective infill development of existing oil and gas fields will increasingly rely on interdisciplinary solutions requiring the expertise of both petroleum geologists and engineers to maximize recovery and economic viability.