Reservoir characteristics of Shahejie Formation in Qingdong Sag, Jiyang Depression

The exploration degree of the Qingdong Sag of the Jiyang Depression is very low,so it is necessary to carry out studies of basic geological conditions such as sedimentary reservoir.The Shahejie Formation is the main oil-bearing sequence in the Qingdong Sag.Based on core,thin section and physical property analyses,the reservoir characteristics in the study area have been systematically researched.Pores in the Shahejie Formation are mainly primary intergranular,intergranular dissolved and intragranular dissolved ones.The 4th member of the Shahejie Formation is from the early diagenesis stage B to the late diagenetic stage A,and has strong heterogeneity.The 3rd member of the Shahejie Formation is during the early diagenesis stage B,and has high porosity and high permeability.Sedimentary microfacies and diagenesis are the main influencing factors for reservoir property in the study area.Corrosion happens when organic acid generates as organic matter expulsing,which improving reservoir property.Cementation and compaction make the reservoir porosity and permeability become worse.