Hydrocarbon Potential Assessment Methods in Complex Fault Zones: A Case Study of the Southern Pinghu Structural Belt, East China Sea

Frequent tectonic activity in rift basins has led to complex fault zones, which have led to extensive hydrocarbon distributions and tremendous resource potential. This study investigated the hydrocarbon potential in the southern Pinghu structural belt, focusing on fault traps in complex fault zones. Through fault sealing analysis and gas detection attenuation methods, this study aims to improve exploration success rates. The application outcomes demonstrate that the Shale Gouge Ratio (SGR) threshold for achieving the lateral sealing of faults in the southern Pinghu structural belt is 34%, with a critical fault throw of 100 m. Regions where the fault’s lateral sealing zone corresponds with areas exhibiting anomalous gas responses are deemed promising for hydrocarbon accumulation. Additional analysis indicates that favorable fault trap development occurs along the foot walls of significant faults, particularly in the eastern sector of the study area. The findings are corroborated by actual drilling data, affirming the efficacy of these methods in pinpointing hydrocarbon traps within complex fault zones and offering valuable insights for their broader global application.