Tectonic Characteristics Of The Third Number Of Shahejie Formation And Tectonic Effects On Sedimentary System And Reservoir Forming In Gaoliu Region Of Nanpu Sag

Nanpu sag lies in the north of Huanghua depression,Bohaiwan Basin,it is an continental fault basin,with the characteristic of northern-faulted and southern-overlapped structure.Gaoliu region lies in the north of Nanpu sag,which consists of Gaoshangbao structure,Liuzan structure and Shichang sub-sag.This paper takes theories of structural geology,sedimentology,basin analysis and petroleum geology,based on the data of seismic,logging,and cores.Firstly,studying the areal structure,characteristics of tectonic evolution and the activity rate of bounding faults in different depositional stage.Then,combining the ancient landform characteristics,analysis tectonic control function to the depositional system,make sure the characteristics of sedimentary responses in different tectonic evolution stages.From this,summarize the tectonic function to the reservoir-formation.And research the relationship among tectonic,sediment,and reservoir-formation.According to the surface of unconformity,stratigraphy depositional pattern and the characteristic of bounding faults,the tectonic evolution in Gaoliu region can be divided into four phrases,such as the original rift phase?Es₃⁵?,the major rift phase?Es₃⁴-Es₃¹?,the rift subducting phase?Es₁-Ed?and the depression phase?Ng-now?.The target stratum can be divided into three sub-structural layers,such as Es₃⁵sub-structural layer,Es₃⁴-Es₃² sub-structural layer,Es₃¹ sub-structural layer.The activities of Xinanzhuang fault and Bogezhuang fault exist differences and episodic features,as a result,it cause the characteristic of stratum thicken in different depositional stages.The mainly sedimentary facies Gaoliu region is fan delta plain,fan delta front and lacustrine facies.The bounding faults control the type and diffusion of depositional system.In Es₃⁵,the bounding faults just start to develop,with the characteristic of low sedimentation rate and fast landscape changing,the mainly fan delta plain is distributed near the bounding faults.In Es₃⁴-Es₃²,due to the fast rifting,the activity of Xinanzhuang fault increases,as a result,source-materials mainly come from Bogezhuang fault,the fan delta plain and fan delta front prograde to Shichang sub-sag.In Es₃¹,with the increasing activity of Bogezhuang fault,tectonic transfer happens,the source-materials mainly come from Matouying uplift,and the depositional system prograde to the Shichang sub-sag.Gaoliu region exists six kinds of traps,such as pinch-out of updip sandstone,lens-shaped sandstone,fault barrier,lateral pinch of sandstone,unconformity barrier and unconformity overlap.Due to the activity of bounding faults,the types of traps and distribution in different sedimentary are diverse.Three kinds of favorable traps can be predicted in plane.Multi-phase source rock,reservoir and cap rock are conducive to the formation of lithologic traps.