Sedimentary evolution and oil-bearing sand body distribution of Chunguang area,western margin of Junggar basin

Through comprehensive utilization of core,drilling,logging and seismic data,the research of sedimentary facies of spring exploration area in Chunguang oilfield has been carried out,and four kinds of sedimentary systems,namely fan delta-lacstrine,braided river delta-lacustrine,alluvial fan-braided river and meandering river-meandering river delta have been determined.Under a sequence stratigraphic framework,in combination with paleo geomorphology characteristics of exploration area in Chunguang oilfield,it is believed that the distribution characteristics in each series of strata of sedimentary system are controlled by paleo geomorphology.On the basis of this,the sedimentary evolution characteristics of exploration area in Chunguang oilfield has been made clear,and then the favorable sedimentary facies belt for each series of strata has been determined.Combining with characteristics of hydrocarbon accumulation of exploration area in Chunguang oilfield,gulch sand bodies of alluvial fan in first member of Neogene Shawan formation,lateral pinchout belt of Shawan river channel sand body,Paleogene beach-bar sand body and cretaceous fan-delta stratigraphic onlap/denudation zone are favorable exploration zone.