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侏罗系和下白垩统下段在库车坳陷南缘由北向南尖灭 ,形成一系列地层超覆圈闭。侏罗系圈闭以侏罗系下段滨浅湖砂体为储层 ,中上段滨浅湖沼泽相泥质岩为盖层。下白垩统下段滨浅湖砂体为储层 ,中上段浅 -半深湖泥质岩为盖层 ,具有良好的储盖组合。圈闭底板为前震旦系和震旦 -下奥陶统 ,其底板的封堵性直接影响圈闭的有效性。研究认为 3种情况下底板可以形成较好的封堵 :( 1)底板为前震旦系 ;( 2 )底板为震旦 -奥陶系碳酸盐岩 ,当圈闭前端底板岩溶不发育 ,可成为有效封堵面 ,形成有效圈闭 ;( 3 )底板为震旦 -奥陶系岩溶发育的碳酸盐岩 ,但地层圈闭储层与底板岩溶储集体连为一体 ,圈闭前端震旦 -奥陶系与前震旦系呈断层接触 ,上覆下白垩统中上段盖层 ,构成复合圈闭。库车坳陷具有丰富的油气资源 ,南缘地处坳陷内三叠系 -侏罗系烃源岩油气运移指向区 ,油源、运移聚集和圈闭条件都比较优越。因此库车坳陷南缘地层超覆圈闭具有良好的含油气前景。
The lower Jurassic and Lower Cretaceous strata plunge from north to south in the southern margin of the Kuqa Depression, forming a series of overlying stratigraphic traps. The Jurassic traps are mainly composed of the Lower Jurassic littoral-shallow sand body as the reservoir and the upper-middle-shallow bank swamp facies as the cap rock. Lower-Lower Cretaceous Binanshahu sandstone reservoir is reservoir, middle-upper shallow-semi-deep lake mudstone is cap rock, with good combination of reservoir and cover. The traps are the Pre-Sinian and Aurora-Lower Ordovician traps, and the sealing of the trays directly affects the effectiveness of traps. The study shows that the bottom plate can form a better sealing in three cases: (1) the bottom plate is the former Sinian system; (2) the bottom plate is Aurora-Ordovician carbonate rock. When the trailing front bottom plate karst is not developed, (3) the bottom plate is a carbonate rock with Aurora-Ordovician karst development, but the stratum trap reservoir is connected with the floor karst reservoir, and the front end of the trap is Aurora - Ordovician faulted contact with the former Sinian, overlying the upper Cretaceous caprock and forming a composite trap. The Kuqa Depression is rich in oil and gas resources. The southern margin is located in the oil-gas migration point of the Triassic-Jurassic hydrocarbon source rocks in the depression. The oil source, migration, accumulation and trapping conditions are superior. Therefore, the overlying traps in the southern margin of the Kuqa Depression have good hydrocarbon-bearing prospects.