渤海海域新生代褶皱作用

The Cenozoic folding in the Bohai Sea waters

基于地震资料解释,总结了渤海海域新生代褶皱作用的类型、控制因素及分布。从力学成因上看,渤海海域褶皱作用可以划分为4种类型,即与拉张作用有关的、与扭动作用有关的、与重力滑动诱导的挤压作用有关的和与压实、底辟等重力作用有关的褶皱作用。与拉张和挤压有关的褶皱作用发生在古近纪,分别沿长期活动的控制性断裂和斜坡带分布。与扭动有关的褶皱作用发生在新近纪晚期,主要分布在盆地东部郯庐断裂经过的地方。重力褶皱中的披覆褶皱作用贯穿于整个新生代,分布在凸起上;而盐底辟褶皱作用分布局限,目前仅在盆地南部的莱州湾凹陷有所发现。从目前渤海海域油气勘探实践看,沿断裂带分布的与新近纪晚期扭动褶皱相关的圈闭是有利的储油气构造。

This paper summarizes the types of the Cenozoic folding, their controlling factors and distribution in the Bohai Sea waters based on seismic data interpretations. According to their mechanical genesis, the folding can be classified into four types which are respectively related to extension, wrench, compression induced by gravity sliding, and compaction and diapirism caused by gravity. Extension-related folding and compression-related folding happened during the Paleogene and these two types of folds are distributed along the long-active main faults and slopes respectively. Wrench-related folding happened during the Neogene and the folds are distributed in the eastern part of the Bohai Bay Basin where the Tanlu fault zone passes by. Among the gravity-related folding types, the drape folding had been active in the whole Cenozoic and the folds are distributed on the salient. While the salt diapirism folding was restricted to certain areas and the faults occur only in the Laizhou Bay sag at the south of the basin. The current exploration results in the Bohai Sea waters show that traps located along the faults and related to the wrench folds of the Late Neogene are favorable for oil and gas accumulation.