古近系构造样式对油气成藏的影响——以歧口凹陷为例

从歧口凹陷地质构造样式分析入手，结合构造动力学机制，探讨其对输导体系和储集体系的影响，进而探讨油气成藏的主要影响因素。结果表明:歧口凹陷古近系NW-SE向多次凹复式箕状断陷结构和N-S方向歧口主凹双断复式地堑结构，主要受沧东伸展断裂系统和歧口伸展断裂系统的控制，在平面上形成了多凸多凹、凹隆相间的构造古地貌格局，为岩性油气藏的形成创造了有利空间；歧口凹陷构造样式控藏影响，体现为在油气运移时，主干断层控制油藏形成，次级断层改造油气分布，形成优势输导体系；在油气聚集时，有利储积相带发育，构造坡折带发育，有利圈闭发育.结合前人对油气成藏模式的研究，提出歧口凹陷4种成藏模式，即:陡坡带成藏模式、缓坡带成藏模式、断阶带近源成藏模式和盆内坡折带成藏模式。优选了勘探目标区，经钻探实例验证，取得良好效果。

Influence of Paleogene Structural Pattern on Lithologic Reservoir:A Case Study of Qikou Sag

In this paper, we discuss the influence of structural figuration and structural dynamics on the transporting and reservoiring system in the Qikou sag.The results show that the Paleogene graben faults generated complex half graben-like framework on NW-SE orientation and complex duplex fault graben on N-S orientation in the Qikou sag, constrained by the Cangdong extensional fault system and Qikou extensional fault system.On a plane, the structural palaeogeomorphology pattern with the multi-convex and multi-concave, convex and concave separation formed a favorable space for lithologic reservoirs.The tectonic style of Qikou sag controlled the distribution of hydrocarbon accumulation.The main faults control the oil and gas migration and accumulation and secondary faults rework the oil and gas distribution and form the advantages conduit system.Both favorable reservoir facie and structural slope are prone to the formation of favorable trap.In the Qikou sag, we conclude four types of oil-gas accumulation, i.e.steep slope, gentle slope, broken joint associated with near-source, intrabasinal knick zone.The selected exploration targets have been verified by drilling instance.
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