The shift of strike-slip faults in the northern part of the Tahe Oilfield in the Tarim Basin and its structural implications

The strike-slip fault is a crucial transport system for Ordovician oil and gas migration and accumulation in Tahe Oilfield. It controlled the formation and distribution of oil and gas reservoirs. To clarify the formation and evolution processes of strike-slip faults is of important significance for exploring the laws of hydrocarbon transportation and accumulation in this area. Based on high-precision 3D seismic data and detailed structural explanation, this study investigates the development characteristics, structural deflection phenomena, and the evolution process of strike-slip faults in the Tahe area. The results indicate that there is a typical feature of the strike-slip fault system widely developed in the Cambrian to Middle-Lower Ordovician carbonate formations in the Tahe area. Among them, there are mainly characteristic NNE- and NNW-trending conjugate strike-slip fault systems in Tuofutai-Tahe area. In Aiding-Yuqi area, there are mainly NE-trending and SN-trending strike-slip fault systems whose trendings were obviously deflected. Studies on the fault activity and evolution reveal that strike-slip faults with different striking directions have similar activity periods. The strike-slip faults of the early stage in Yuqi area of the northern and Tuofutai-Tahe area of the southern, belong to the same structural system. They were formed and strongly activated due to influnce of the near SN-trending stress during the Middle Caledonian period. During the Early Hercynian period, the shift of the near SN-trending stress to the NW-SE-trending stress caused the rotation of strata from the NW-striking to the SE-striking in Yuqi area. With the material foundation laid for the formation of the Akekule Uplift, the strike-slip faults formed during the Middle Caledonian period in Yuqi area also deflected to the SE-striking faults, with a maximum lateral deflection distance of 25.4 km. The analysis of the deflection phenomena of structures in northern Tahe area reveals the development and evolution processes of faults in the area. This research provides a basis for exploring the process of hydrocarbon transportation and accumulation.