渤中凹陷断裂成因类型及其对成藏的控制作用

GENETIC TYPES OF THE FRACTURE AND ITS CONTROL ON HYDROCARBON ACCUMULATION IN BOZHONG SAG

在对渤中凹陷进行大量精细地震解释基础上,按照断层的发育过程,将渤中凹陷古近系—新近系的断裂划分为消亡型、继承型、继承-改造型和新生型。结合目前所发现的油气藏分布特点,确定不同类型断裂对油气的运移和成藏具有不同的控制作用。消亡型断裂是由早期伸展作用而成的正断层,古近纪发育,新近纪停止活动,与该型断裂有关的油气藏很少;继承型断裂是从古近纪到新近纪持续受伸展作用形成的正断裂,因长期活动,该型断裂以垂向输导油气为主,以油气成藏为辅;继承-改造型断裂在古近纪受控于伸展作用,而在新近纪受控于剪切作用,该型断裂不但有利于油气的输导和运移,而且利于油气的成藏;新生型断裂在新近纪时期受强烈的剪切作用所形成,其与继承型或继承-改造型断裂相伴生时较有利于成藏。

Based on numerous seismic interpretations to Bozhong sag,the study classifies the fracture of Neogene and Paleogene into four types in terms of the process of faults development. They are extinct fracture, inheritance fracture, inheritance-reformed fracture, and new fracture.Combined with the current statistics of reservoir,the analysis shows that each type has a different effect on the hydrocarbon migration and accumulation. Extinct fracture developed from Paleogene to early Neogene is normal fault formed by extensional effect and has few reservoirs. Inheritance fracture is sustained extensional normal fault from early Paleogene to late Neogene. It plays a major role in the vertical transporting oil and gas and a supporting role for hydrocarbon accumulation.Inheritance-reformed fracture controlled by extensional effect in Paleogene and shearing action in Neogene is not only conducive to transport oil and gas, but also conducive to hydrocarbon accumulation. New fracture developed by strong shearing effect in Neogene is more favorable to accumulate oil and gas when accompanying with inheritance fracture or inheritance-reformed fracture.