Identification of sandstone-rich zones in upper bathyal deep-water slope environment, south Texas Gulf Coast

Abstract

This abstract documents results of a 3D seismic investigation undertaken to search for prospective hydrocarbon sandstone-rich zones within the Eocene Yegua Formation, which is located in a shale-dominated environment in Jackson County, South Texas. Because of the preponderance of shale in this environment, diligent efforts and methods are required to identify sandstone-rich zones. First, we used seismic sweetness and instantaneous frequency attributes to identify sandstone zones. This procedure was then followed by the frequency-fusion method to validate the results and estimate the thickness of the predicted sandstone-rich intervals. Our results show that the sandstone-rich zones are characterized by low frequencies ranging from 0–15 Hz. We interpret the depositional pattern to be slope channels, and slope fans deposited in upper bathyal environment, trapped by down-to-the-basin growth-faults and shale ridges. On the basis of the frequency-fusion, we infer that the thickness of the sandstone-rich zones range from about 30–45 m (∼100–150 ft.).