HYDROCARBON ACCUMULATION CHARACTERISTICS OF COMBINATION TRAPS IN THE ABDOMEN OF JUNGGAR BASIN

Junggar Basin is a highly explored basin,with few unexplored structural traps remaining.Thus the lithologic trap,and even the structural lithologic trap,have become the main target of oil-gas exploration.This is especially evident in the abdomen of Junggar Basin,where the weak structural movement resulted in less structural trap,making it more urgent to look for lithologic or structural lithologic combined traps.According to the sedimentary facies analysis with seismic stratigraphy and sequence stratigraphy,in the abdomen of Junggar Basin,the Jurassic Sangonghe formation and Bandaowan formation in the main target strata are mainly flurial-delta-semi-deep lake facies.And the reservoirs are mainly composed of various kinds of channel sand and deltaic front sand.In accordance with the research on structural evolution,the suprastructure (Jurassic and overlying formation) in the abdomen of Junggar Basin is mainly monoclinal formation uplift to the north.This structural background,combined with various kinds of lithologic sand,forms combination trap.The complicated distribution of Jurassic and Cretaceous sand results in the complex relationship between oil and water in the study area,thereby makes the combination on accumulation quite complicated.