渤海海域庙西北洼陷新生代断裂特征及对油气成藏的控制作用

Cenozoic fracturing characteristics of Miaoxibei depression and its control on hydrocarbon accumulation

为了揭示庙西北洼陷断裂与油气成藏的关系,利用该区构造解释成果结合钻井资料对新生代断裂几何学特征、活动演化特征进行了较为系统的分析。结果表明庙西北洼陷经历了裂陷、拗陷、反转等演化过程,不同发育阶段经历了伸展、走滑、反转等单一或多种构造应力复合叠加作用,尤其是郯庐断裂上新世后期新构造运动剧烈,造成该区晚期断裂非常发育;断裂的显著特征为纵向上分层差异变形和相互切割,并构成丰富多样的空间组合样式;不同断裂体系对油气成藏的控制作用不同,基底断裂控制了该区的构造格架及烃源的形成,盖层断裂控制主要圈闭的形成,深浅两套断裂连锁系统共同组成油气垂向运移通道,其平面上的重叠区是油气优势运移聚集区。

In order to make out the relation between fracturing characteristics of Miaoxibei depression and hydrocarbon accumulation, the structural interpretation and drilling data have been used to carry out the systematical analysis of the geometry features and evolution characteristics of the Cenozoic fracturing. The results indicate the Miaoxibei depression has undergone the evolution processes of rift, depression and reversal. In different development stages, the singular and multiple tectonic stress such as stretching, strike-slipping and reversal have been undergone. The obvious fracturing characteristics show layered differences and interaction cutting laterally, and demonstrate various combination styles in space distribution. Different fracturing systems have different control on hydrocarbon accumulation. The structural framework and source rock are controlled by the basement fractures, the main traps are controlled by the cover faulting. Two suits of fracturing systems together formed the migration channel and the superimposed area on the plane is the favorable hydrocarbon migration and accumulation area.