Provenance Characteristics of Pinghu Tectonic Zone in Xihu Sag

With the process of oil and gas exploration in Pinghu tectonic zone of Xihu Sag,East China Sea shelf basin in recent years,it is found that there are different provenance characteristics in the different parts of this tectonic zone,and which affect the development of sand bodies and the physical properties of the reservoirs.No study,however,has carried out on these differences in the previous publications.Based on the study of heavy mineral assemblage,microscope observation,physical property data,the authors analyzed the provenance characteristics of sandstones in Pinghu Formation and Huagang Formation,respectively.It indicates that there are obvious differences in the heavy mineral assemblages in Pinghu Formation between the north segment and the south segment of Pinghu tectonic zone,but with relatively less difference in Huagang Formation.The combined study of sedimentation and paleo-tectonic evolution in the slope zone indicates that during the sedimentary period of Pinghu Formation in the fault depression stage,the difference in the rock composition of exposed basement resulted in the relatively obvious difference in the development of sandstones in the different segments,but relatively less difference occurred in Huagang Formation that was deposited in the depression stage.