南堡凹陷断层对中、上部含油组合油气成藏的控制作用

南堡凹陷断层极其发育,依据断层形成时期、变形特征及形成演化机制,可将南堡凹陷断裂系统划分6种类型(Ⅰ—Ⅵ)。其中,Ⅲ型、Ⅴ型和Ⅵ型断裂系统是中、上部含油组合的主要断层类型,也是重要的控藏断层类型;Ⅲ型断裂系统为晚期形成的断层,主要对中—上部含油组合的油气起封闭或调节作用;Ⅴ型和Ⅵ型断裂系统为长期发育的断层,是油气从源岩层向中浅层储层垂向运移的主要通道。晚期活动断层形成的断层相关圈闭是形成油气藏的主要圈闭类型;晚期形成的断裂密集带控制油气藏的分布;断层分段生长形成的古转换带控制了沉积体系及砂体的展布,控制了油气藏的分布;断层对盖层的破坏程度控制了油气聚集的层位;断层封闭性演化控制了断层圈闭中油气的富集程度。

Control Action of Faults on Hydrocarbon Migration and Accumulation in the Middle and Upper Oil-Bearing Group in Nanpu Sag

Nanpu sag faults and their development can be systematically classified into 6 types (ⅠⅥ)according to the periods of fault development, the deformation behaviour, and the evolution mechanisms.Fault systems Ⅲ,Ⅴ,and Ⅵ are the main fault types in the middle and upper oil-bearing group,and they are also the important controlling pool fault types.Among them,type Ⅲ,a latterly-developed fault system,serves to seal and adjust the hydrocarbon in the middle and upper oil-bearing groups;while type Ⅴ and Ⅵ,which are fault systems with a long history,serve as the main pathways for the vertical migration of hydrocarbon from source rock to intermediate and shallow reservoirs.The traps related to the faults resulting from latterly developed faults are the primary candidates for the development of hydrocarbon reservoirs; The fault intensive areas developed latterly control the distribution of hydrocarbon reservoirs;The palaeo-transition areas caused by the faults development at different periods provide the location of the depositional systems and sand systems,and limit the distribution of the hydrocarbon reservoirs;The breakdown of the cap rock by the faults controls the positions of the hydrocarbon accumulation;And the sealing of the fault controls the enrichment degree of the hydrocarbon in the fault traps.