Shallow-water-platform carbonate reservoirs of Permian age have accounted for more than half of the oil production in the Permian Basin, one of the largest oil-producing regions in the United States. Despite more than 70 yr of production, including advanced primary and secondary development, however, these reservoirs still contain as much as two-thirds of the original oil in place. This low recovery efficiency is linked to an incomplete understanding of the geological and petrophysical heterogeneities of these reservoirs and their controls on fluid flow in the subsurface.

This study offers a high-frequency sequence stratigraphic model of carbonate-ramp strata of the San Andres Formation. It also documents, at the cycle scale,  the inner-ramp through outer-ramp portions of three high-frequency sequences and describes and maps carbonate facies within a high-frequency sequence framework.

Authors of this report summarize the results of integrated geologic characterization of the Frontier Formation along the Moxa Arch in southwestern Wyoming in four major areas of study: (1) stratigraphic and depositional systems, (2) diagenesis of reservoir sandstones, (3) disttribution of natural fractures, and (4) horizontal stress orientation. The authors describe the geological elements that were found to be important in characterizing these low-permeability sandstone reservoirs.