Neogene differential structural inversion and hydrocarbon accumulation in the Yitong Basin, NE China

摘要

Based on the latest seismic and drilling data, this paper analyzes the differential transformation features, evolution/ deformation rules and kinetic background of the Neogene inversion structures in the Yitong Basin, Northeastern China, aiming to find the relation of differential structure inversion and hydrocarbon accumulation. At the northwestern edge of the basin, inversion structures are dominated by right-lateral strike-slip thrusts, which can be divided into three types: high-swelling overturn thrust, moderate-swelling echelon thrust and low-swelling rupture thrust – all of them formed a fault-fold belt 2 to 4 km wide along the northwestern, providing good conditions for hydrocarbon accumulation. At the southeastern edge, inversion structures are mainly composed of right-lateral compresso-shear and uplifting tilts, and also arch-tension faults at the tops of Jianshan, Wanchang, Soudeng and other structural belts, which destructed the pre-existed reservoirs. These structures originated as a result of the compression and uplifting of the northeastern China continent which occurred due to the back-arc spreading after the westward subduction of the Pacific plate, and also the long-distance compression caused by the collision between the Indian plate and the Eurasian plate. In addition, their origin is related to the position and intensity of uplifts at the edges of the Yitong Basin.