Depositional Model and Geological Significance of Turbidite in Western Bohai Bay Basin

There are a series of typical slump turbidite fans in the deep lake of the downthrown block in Qinan fault zone of the eastern Qikou sag in Bohai Bay basin,which have been major domains for oil-gas exploration in this area.According to the lithofacies,electrofacies and grain size features,the turbidite fans here can be divided into inner-fan,mid-fan and outer-fan subfacies.Fault episodic activity,flood events and the paleotopography are the main factors affecting the formation and distribution of the turbidite fans.These turbidite fans are characterized by the small area distribution of a single fan,a series of turbidite fans along the contemporaneous fault downthrown block; thin single-phase sand body,good inheritance,multi-phase superimposition and big cumulative sand thickness; good assemblage of source-reservoir-cap rock and high fullness of oil and gas.