The steep slope zone is an important structural belt for hydrocarbon exploration in half graben-like sag, and the structural-lithologic composite traps are developed in this zone. These traps are important prospecting areas. However, it is very complex in structure, sedimentary facies and control factors on distribution of the structural-lithologic composite traps in this zone. Taking Shinan steep slope of Bozhong sag as an example, this paper focuses on the genesis and distribution regularity of the structural-lithologic composite traps in the steep slope zone. There are four types of structural-lithologic composite traps developing in the Shinan steep slope zone, and they are updip punch-out trap, downdip punch-out trap, lateral punch-out trap and physical property sealing trap. The distribution are controlled by the types and location of slope break zones, collocation relations of direction of drainage system and palaeogeomorphology, and as well as base level change. The steep slope break zone showing corner-like in plane is the most optimal field of the hydrocarbon exploration of the structural-lithologic composite trap. The structural-lithologic composite traps, which develop in the various series of strata and are distributed widely, are helpful to supplement shortages of the singular structural trap slope zone and reduce the exploration risk of the Shinan steep slope zone. The thinking of the structural-lithologic composite trap exploration should be built in the early exploration phase in the Shinan steep slope zone.%陡坡带是箕状凹陷油气勘探的重要构造带,构造-岩性圈闭发育,是油气勘探的重要领域,但是陡坡带构造、沉积相带迁移变化和构造-岩性圈闭分布的控制因素复杂.以渤海海域渤中凹陷石南陡坡带为例,分析陡坡带构造-岩性圈闭的成因与分布规律.石南陡坡带发育上倾尖灭型、下倾尖灭型、侧向尖灭型和物性封闭型等4种类型的构造-岩性复合圈闭,其分布主要受控于坡折带类型与分布、水系方向与古地貌的配置关系以及基准面的旋回性变化.墙角式陡坡折带处是寻找构造-岩性复合圈闭最有利的位置.发育在不同层系、分布广泛的构造-岩性圈闭有利于弥补石南陡坡带纯构造圈闭的不足,降低陡坡带的勘探风险,石南陡坡带从勘探的早期就应建立构造-岩性复合圈闭勘探的思路.
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