Impact of inversion tectonics on the spatial distribution of hydrocarbon traps in the NW Persian Gulf and the southern Dezful Embayment, SW Iran

Inversion tectonics has a major impact on distribution of fault-controlled hydrocarbon traps in the fold-andthrust belts. In order to characterize the spatial distribution of several fault-controlled hydrocarbon traps adjacent to the Nourooz-Hendijan-Izeh Fault, this study describes the structural and tectono-sedimentary evolution of the fault based on the geological interpretation and tectono-sedimentary analysis of seven seismic sections in the Bahregansar, Hendijan, Tangu, and Rag-e-Sefid oilfields in the NW Persian Gulf and the southern Dezful Embayment. The results indicate that the Nourooz-Hendijan-Izeh Fault is a segmented pre-existing basement fault with steep dip, which reactivated to at least seven tectonic phases. Three-phase inversion tectonics along the Nourooz-Hendijan-Izeh Fault occurred at the Late Devonian-Carboniferous (positive inversion), PermianEarly Triassic (negative inversion), and Late Cenomanian-Early Turonian (positive inversion) boundaries and modified the evolutionary history of the sedimentary basin. Inversion affected hydrocarbon trap development at the Late Cretaceous and controlled their current conditions in the NW Persian Gulf and the southern Dezful Embayment along the northeastern margin of African-Arabian plates. Considering the hydrocarbon migration at the Late Miocene in these regions up to now, the N-S trending anticlines (Arabian trend) have a larger share of oil and gas in their hydrocarbon traps and lower hydrocarbon exploration risk than the NW-SE trending anticlines (Zagros trend). Mild to moderate inversion structures can be considered as preferred petroleum exploration targets.

Automated summary

The study revealed that the Nourooz-Hendijan-Izeh Fault is a segmented pre-existing basement fault that underwent reactivation in at least seven tectonic phases. Inversion tectonics affected hydrocarbon trap development in the Late Cretaceous and controlled their current conditions in the NW Persian Gulf and the southern Dezful Embayment. Mild to moderate inversion structures are considered preferred petroleum exploration targets in the region.