Abstract: Controlled by the factors including anticline, fault, sedimentary cycle and sedimentary facies, four oil-bearing horizons series of the 1st member of Shahejie Formation, the 1st,2nd and 3rdmembers of Dongying Formation developed in Taiyangdao -Kuihuadao structural belt frombottom to top.Vertically, oil-gas reservoirs are characterized by the gas-bearing layers developed in the top and the bottom, and oil formation developed in the middle part, that is to say, gas reservoir mainly formed in the middle-upper part of the 2ndmember of Dongying Formation, oil-gas reservoir mainly formed in the lowerpart of the 2nd member of Dongying Formation,the thicker pure gas reservoir developed in the 3rd member ofDongying Formation. Based on the study of organic evolution history and the configuration of faulting movement, trap forming and oil-gas migration, the result shows that three stages of reservoir forming had occurred in the study area, namely, early stage of reservoir forming occurred in the end of the 1st member of Shahejie Formation deposition, mediumstage of reservoir forming occurred in the end of Dongying Formation deposition, the late stage of reservoir forming occurred during a period fromGuantao Formation toMinghuazhen Formation.This area stillhas a relatively big potentialityboth vertically and horizontally,which result fromthemulti-stagereservoir-forming anddifferential migrating and accumulating.Several promising traps such asTaiyangdao structure,Kuihuadao structure, faulted nose in the easternKuihuadao, and faulted nose in the western Kuihuadao, are determined through study

Key words: oil-bearinghorizonsseries, oil-gasreservoir;reservoir-formingpattern;exploration potential;Taiyangdao-Kuihuadaostructural belt