Study On Es3-4 Pore Evolution In Qiaokou Area Of Dongpu Depression

At present,the researchers have done a lot of research on the Qiaokou area of the Dongpu Sag,but there are few studies on the pore evolution and diagenesis of the deep and ultra-deep reservoirs in the Qiaokou area,and there is no detailed description of the pore evolution law,including the specific The use of methods,formulas,etc.In order to clarify the pore evolution model of the reservoir and the establishment process of its model.The main target stratum of Shahejie Formation Shahe and Shasi in the Qiaokou area of Dongpu Sag is taken as the research object.Using CT technology,scanning electron microscope technology.Based on the regional geological profile,the sedimentary facies types and the plane distribution of sand bodies are studied,and the factors affecting diagenesis are identified.The diagenetic stages of each period are qualitatively divided,the history of pore evolution is analyzed,the evolution model is established,and the reservoir is classified and evaluated..The results show that the Shahe reservoir in Qiaokou mainly develops the subfacies of the fan front in the lake bottom fan,including the sedimentary microfacies such as the underwater natural levee,the meandering delta front,and the underwater distributary channel.Compaction,clay mineral cementation or quartz secondary cementation and metasomatism are the main reasons for the poor permeability of reservoir pores.The dissolution of acidic fluids improves the reservoir properties to some extent.Calculating the pore evolution process,the original porosity is about 34.87%,the porosity after compaction is 19.85%,the porosity after carbonate and quartz cementation is 7.93%,and the porosity after acid dissolution is 11.21%.It can be seen from the reservoir evaluation that the type I reservoirs are mainly distributed in shallower areas and are the main areas for oil and gas exploration and development;the type II reservoirs are widely distributed and have great potential for oil and gas exploration.By carrying out the pore evolution of deep reservoirs,it provides a certain theoretical support for the search for high-quality reservoirs.