The Chunguang oilfield is located in a simple structure named Chepaizi slope zone in western margin of Juggar Basin

northwestern China.The reservoirs are mainly stratigraphic and lithologic type of outside hydrocarbon source.The Neogene Shawan Formation

Paleogene

and Cretaceous

are all the exploration targets.Analyses of depositional characteristics show that the Shawan Formation developed mainly alluvial fan and braided river depositional system

the Paleogene and the Cretaceous grew braided river delta sedimentary system.A study based on semdimentary features of the area had been carried out to answer questions concerning on reservoiring conditions.Analyses of oil-source correlation show that the Changji sag in the east and Sikeshou sag in the south of the area had the potential to provide hydrocarbon and their Jurassic and Permian formaiotns were the major hydrocarbon-generating ‘factories'.Migration pathways for hydrocarbon were regarded as the major controlling factor for the reservoiring of oil in the area.Three relevent elements had been thoroughly studied(unconformity

sand sheet and fault).The result indicates the existence of a highly efficient pathway system.A hydrocarbon migration pattern was established for the area based on the study.Reserveroi features analyses of the area were used to determine the major controlling factors

establish of reservoring model and guide the exploration.