Abstract: Wu-Xia fault belt is located in the eastern part of thrust zone in northwestern margin of Junggar basin, which was tectonically the most active area here. The multistage tectonic activities allowed the lateral and vertical styles of the fault belt to be of complexity and diversity. It is vertically divided into the deep fault system and the shallow fault system bounded by the bottom of Jurassic. Because of differences in active period and intensity of the fault, the deep and shallow fault systems showed obvious differences in controlling the hydrocarbon accumulation. The Triassic-Jurassic fault active period matched well with the hydrocarbon generation and expulsion periods and had an important effect on hydrocarbon migration and accumulation. The active faults and the unconformities form the Z-like transportation networks, resulting in stepped hydrocarbon migration and accumulation from deep strata to shallow strata and from sag centers to basin margins in this region.

Key words: Junggar basin, Wuerhe-Xiazijie fault belt, fault activity, hydrocarbon migration and accumulation, fault system, migration network