ANALYSIS OF HYDROCARBON ACCUMULATIONRULE IN GRABEN STYLE BASIN——A CASE FROM SOUTH CHALUHE FAULT DEPRESSION OF THE YITONG GRABEN

Yitong Graben,subordinated to south section of Jia-Yi Graben,is the north-extension part of Tan-Lu Fault Zone.Chaluhe Fault Depression of the Yitong Graben is an graben style basin.According to comprehensive analysis,sublacustrine fan deposit which possesses gravity flow property is the domain sandstone sedimentary in this subsidence.Subaqueous debric flow or collapse-fall accumulational glutenite of inner fan has shut off capacity to hydrocarbon,while,the sandstone of middle fan,to some extent,has storage of hydrocarbon.The sandstone of middle fan is apt to form lithological trap,in case subaqueous debric flow or collapse-fall accumulation of inner fan is developed.Vertically,this style basin possesses comprehensive hydrocarbon potential and is prone to form multiple oil-bearing formations.Meanwhile,horizontally,the profit oil and gas exploration zone is located at basin both sides marginal zone which is away from controlling fault at some distance.Especially,the basin marginal zone where forms fracture is prone to form lithological reservoir.The exploration aim in this style basin should be focused on tongue-shaped lithological reservoir of middle fan and rolling anticline reservoir.