Grabens overlying diapirs have previously been ascribed to intrusion, withdrawal, or dissolution of salt. We propose, however, that many grabens or half grabens above diapirs form by regional thin-skinned extension of a brittle overburden. This regional extension can initiate and promote piercement of diapiric walls through extremely thick overburdens. This Piercement induced by faulting applies regardless of the overburden density.

The Gas Research Institute, U.S. Department of Energy, and the State of Texas cooperated in joint-venture research to evaluate the infield reserve growth potential of mature gas fields containing conventional reservoirs. Whole cores from fluvial (middle Frio) and deltaic (Vicksburg and Wilcox) reservoirs of the Gulf Coast Basin were compared to diverse types of well logs, analyzed for diagenetic alteration, and calibrated to porosity, permeability, and petrophysical parameters.