Syntectonic depositional systems within the Mt. Enterprise fault zone: Implications for hydrocarbon exploration in Cherokee and Rusk Counties, Texas.

摘要

Central basin faulting such as the Mt. Enterprise Fault Zone (MEFZ) has recently been of interest in the pursuit of new oil and gas plays within the East Texas Basin. Jurassic rifting and basin subsidence allowed a restricted environment depositing an estimated 1200 ft of salt in the central basin followed by late Jurassic Smackover and Haynesville carbonate deposition. Third order progradation of marginal marine influenced deltas onto the shelf margin occurred and was affected by 4th order cycles of sea level change in which Cotton Valley Sands were vertically stacked within the study area. Contemporaneous faulting caused by salt withdrawal produced further accommodation in which Bossier shale has been documented up to 80% thicker. Faulting possibly served as migration pathways linking reservoirs and source beds within the basin. Timing of deposition and faulting indicates that potential oldest reservoir facies are assumed to be thin distal sands within the fault zone but possibly improve upwards through time. Given the depositional system, lateral discontinuity of reservoirs is considered to exist.