Meso-cenozoic tectonic evolution and significance in petroleum geology of Wudun sag in Dunhuang basin

Wudun Sag of Dunhuang basin was newly discovered in Hexi corridor petroliferous sag, its research was still in the initial stage. The structural characteristics and the evolution history were analyzed comprehensively based on 2 D seismic and some boreholes interpretation. Study results indicate based on the structure, the Wudun sag can be divided into three parts: the northern slope belt, central depression belt and the southern fault-bench belt. The evolution history can be classified into five stages, which is early-middle Jurassic faulting period, middlelate Jurassic depression period, early Cretaceous faulting period, late Cretaceous to early Neogene compressional uplift period, late Neogene and quaternary strike slip thrust depression. The sedimentary period of Dashankou group in early Jurassic and Zhongjiangou group in middle Jurassic was favorable for major source rocks, the future direction of exploration area is the braided river delta distributary channel in northern slope belt and the fan delta in southern fault-bench belt.