Hydrocarbon accumulation characteristics and exploration prospects of stratigraphic unconformity in basin margin of Junggar Basin

Based on a large number of geological and geophysical data,it was analyzed in this paper the structural characteristics of stratigraphic unconformity styles in basin margin of the Junggar Basin.The hydrocarbon ac-cumulation feature and pattern were concluded,and the exploration prospect in the future was pointed out.Multiphase tectonic movements and frequent facies change in the Junggar Basin led to the wide development of unconformity in basin edge.In the macro style,three types of on lap truncation,leveled truncate and parallel conformity developed.In vertical direction,there were three or two layers,forming many combination forms of permeability.Influenced by unconformity style structure,permeability combination,geologic background in basin margin and source rock generation condition in basin,the accumulation of unconformity reservoir in basin margin has three characteristics.a) Unconformity trap can form stratigraphic trap and other related types.b) Hydrocarbon generates from multiple sources and charges during different phases.Primary and secondary reservoirs co-exist.c) Unconformity itself has a certain ability of conducting,but the scope of transverse conducting is limited and petroleum migrates along "fault-blanket" type migration systems formed by faults,framework sand body and unconformity.Basin edge unconformity reservoirs have great exploration potentials,so relevant research and eva-luation are needed to develop according to the exploration degree in each area.