Abstract：It is difficult to find more structure traps bigger than 1 km2 in Shichang sub-sag.So finding litho-stratal traps may be the focus of exploration in the future.Combining with the theory of stratigraphy,structure geology and sedimentolgy,through delicate structure and generalized depositional interpretation,we put forward in this paper a new observation that the downthrow side of Baigezhuang fault is intermittently subsided,and the counterpart of Xinanzhuang fault is continuously subsided.We also point out a rule that more litho-stratal traps develop in the active downthrow side than the stable one and the oil pool scale is larger in the former one.So it is the favorable petroleum exploration zone.In this article,we divide Shichang sub-depression into seven different types of litho-stratal traps development area for the first time.This will provide help for the litho-stratal traps exploration.
