Cenozoic Strike-slip Tectonic Character and the Significance of Oil and Gas Exploraton in Eastern Laizhou Bay

Laizhou bay sag is located in the south of Bohai sea region, being a Cenozoic half-graben developed on the basement of Mesozoic. Tan-Lu fault belt is divided into two fault branches, the west fault branch and east fault branch, running across Laizhou bay sag, being the most complex and typical NNE direction dextral strike-slip fault belt in Cenozoic. The east branch fault was extremely active after Oligocene, resulting in the development of a number of NNE direction strike-slip faults and NE direction associated faults, forming complex fault belt. The fault distribution within strike-slip fault belt is consistent with the brittle shear model of dextral simple shear. The dextral drag faulting evidence can be seen on seismic variance slices. Through analysis of phases of fault activities, it is indicated that this area has experienced three major tectonic activities, forming three tectonic inversions. Due to the regional distribution of dextral stress field, the deformation characteristics is different, resulting in the formation of multi-type structural styles, such as folds, compression inversion structures, tilted fault blocks and flower-shaped structures. In the study area, the tectonic characteristics has been analyzed for the first time with 3D seismic data. The result shows that this area has excellent tectonic setting, predominant source rocks and good hydrocarbon migration conditions, and the hydrocarbon exploration potential is great.