Sedimentation And Reservoir Characteristics Of Pinghu-huagang Formation In A Tectonic Region,Xihu Sag Of East China Sea

A tectonic region is located in the south of Western Secondary structure unit in Xihu Sedimentary sag.The study area has good oil and gas show from drilling condition,but due to the complex geological conditions in this region,and the main reservoir is buried deep and scattered,so it is still in the initial stage of exploration and evaluation.Based on core data,well logging and logging data,chemical analysis and seismic data in the study area,the thesis conducts research of sedimentary and reservoir characteristics,clarifies the sedimentary micro facies and their distribution characteristics of the target layers,discusses the influencing factors of reservoir physical property and puts forward reservoir classification evaluation standard.The study has important significance of Drilling Appraisal well and Calculating reserves scale.According to the theory of classical sequence stratigraphy,the target layers,H12 and H11 in Huagang Formation and P4,P2 in Pinghu Formation,are subdivided into three groups.Based on the background of sedimentary paleogeography,according to the characteristics of heavy mineral and seismic progradation reflection characteristics,the thesis determines the main sediment source direction in the study area is the uplift in the western conference.And Combined with granularity and structure of rock and mudstone color,the thesis analyses sedimentary environment and sedimentary evolution in this area,judges that Pinghu and Huagang Formation are developed meandering river delta front and meandering river delta plain deposition.Then,according to coring well lithology,sedimentary structure,and electric logging curve characteristics such as sedimentary facies marks,Pinghu and Huagang Formation are further divided into 11 kinds of sedimentary micro facies.The diagenesis of Pinghu and Huagang Formation mainly include compaction,cementation,dissolution,and the diagenetic stage is in the middle diagenetic A stage.According to physical property,pore structure,content of interstitial material and so on,the thesis divides the reservoir into ?,?,?,? four types and establishes the reservoir classification standard.Core wafer samples of Pinghu and Huagang Formation are classified,P2 section is mainly ?,? types of reservoir,H12 section is mainly ?,?,? types of reservoir and H11 section is mainly ?,?,? types of reservoir.