EVALUATION OF CEMENTING PHASES IN THE CHERRY CANYON FORMATION OF THE DELAWARE MOUNTAIN GROUP, FORD GERALDINE FIELD, TEXAS

The sandstones of the Delaware Mountain Group are an important hydrocarbon reservoir in the Permian Basin. These deep-water submarine fan deposits contain a mixture of skeletal debris and detrital grains deposited during sea level lowstands during Guadalupian time. Intragranular porosity in these sand units can be as high as 30% making them relevant targets for subsurface CO₂ storage. In the Cherry Canyon Formation, the pore space is largely filled with either silica or with authigenic clay minerals. There are also some zones which have been cemented with calcite cements. The calcite cemented zones appear to be linked to the development of secondary porosity derived from the alteration of organic matter and dissolution of skeletal grains. The calcite cemented zones are irregularly distributed and are tightly cemented. These non-reservoir zones are markedly different from the surrounding silica and clay cemented sandstones. Understanding the distribution of the calcite cemented non-reservoir intervals is important for our ability to characterize the reservoir for both hydrocarbon production and potential CO₂ storage because the distribution of cement influences fluid flow paths, reduces reservoir porosity, and causes reservoir compartmentalization. Here, petrographic thin sections from two cores through the lower Cherry Canyon Formation in the Ford Geraldine Field, the 6 Ramsey #26 and Continental TXL 31-3 are used to evaluate the mineralogy, textures, and pore space occlusion by cementing phases in the sandstones. Specifically, the distribution and composition of authigenic clay and carbonate cements is evaluated with both traditional petrographic techniques, cathodoluminescence petrography, and scanning election microscopy with energy dispersive x-ray spectroscopy (SEM-EDS). This work will provide key constraints on the mineralogy and distribution of cementing phases in the Cherry Canyon Formation in the Ford Geraldine field that can be used to inform reservoir models for potential geologic CO₂ sequestration.