渤海湾盆地新生代断裂活动及其对含油气系统和油气分布的影响

渤海湾盆地是一个以新生代为主要成盆期的大型板内裂谷盆地,断裂和裂陷活动是新生代构造变形的主导方式,对含油气系统形成及其油气成藏有广泛和深刻的影响。数量众多、走向不同的断裂活动,形成了多断块、多断陷和凹凸相间的构造格局,奠定了多含油气系统发育的基础。古近纪时期断裂幕式活动引起可容纳空间和湖盆范围周期性扩张与收缩,形成了多套层序和生储盖组合,控制了纵向上多套含油气层系的形成。裂陷中心从盆地外带向盆地中心迁移,使得盆地各凹陷发育史不同,可分为三种类型凹陷;各类凹陷的主要生储盖组合、油气生成-运移-聚集作用过程、圈闭形成史不同,进而导致其油气分布特点存在明显差异。

Cenozoic faulting and its influence on the hydrocarbon-bearing systems and hydrocarbon distribution in the Bohai Bay Basin

The Bohai Bay Basin is a huge intraplate rift basin developed mainly in the Cenozoic. Faulting and rifting were its predominant way of tectonic deformation, which had a broad and profound influence on forming hydrocarbon-bearing systems and hydrocarbon reservoirs. Numerous faulting with different trend decided structure framework with the multi-fault block, multi-fault depression and sag alternating with uplift, which laid down a foundation for the development of multi-petroleum systems in the basin. Episodic fault activities in Palaeogene led to cyclic expansion and reduction in the depositional accommodation space and the lake extent area, and formed multiple sets of sequences and source-reservoir-caprock assemblage and controlled forming multiple sets of hydrocarbon-bearing formations in vertical. The shifting of rifting center from outer part to the central part of the basin resulted in three types of sags with different developing history. The petroleum distribution characteristics in each type of sag had obvious differences because of different major source-reservoir-caprock assemblage, hydrocarbon generation-migration-accumulation processes, and trap formation history.