Structural evolution of Shigang Fault and features of hydrocarbon accumulation in Jinhu Sag

Shigang Fault is located within the centre of Jinhu Sag,which is the major fault zone of this sag with complex structure and evolution process.Based on the 3D seismic data and quantitative analysis,the characteristics of geometry and kinematics of Shigang Fault was analyzed during the late Cretaceous-Cenozoic period,meanwhile the property transferred from extension to strike-slip of the fault and its segmentation character were also discussed.In the late Cretaceous-Cenozoic,Shigang Fault has experienced three processes,including the secondary normal fault stage,boundary normal fault stage and right-lateral strike-slip normal fault stage.On the plane,Shigang Fault has obvious segmentation character,from north to south,the fault property varieties from strike-slip feature to shear-tensional feature,from tensional-shear feature to normal fault feature.It shows a strike-slip component in the northern part,normal fault in the southern part.The differential deformation is controlled by the pre-existing fault in basement,which reveals the change of the extension direction.The extension and strike-slip resulted in the abundant hydrocarbon accumulation in Shigang Fault Zone.