Analysis Of Reservoir Characteristics And Main Control Factors Of Chang-9 In The Southeast Of Wanggoumen Area

In recent years,China’s economy has developed rapidly,and its dependence on oil and gas resources is high,which is not conducive to national security.The resource endowment of the Ordos Basin is excellent,which has a huge supporting role for China’s energy security.With the deepening of development,the Chang 9 section has shown potential for development.However,there is currently a lack of clear understanding of geological issues such as sedimentary microfacies,reservoir characteristics and its main control factors in the southeastern Chang 9section of the Wanggoumen area.Many designs during the development process are unreasonable,which is not conducive to oil and gas exploration and development.Based on the analysis and test data such as logging data,thin section and scanning electron microscope,we studied the stratum division,sedimentary microfacies identification,sand body distribution characteristics,diagenesis,reservoir characteristics and its main control factors analysis of Chang 9 reservoir in the southeast of Wanggoumen area,and the comprehensive reservoir evaluation was finally carried out.Chang 9 member was mainly gray medium fine grained lithic arkose and feldspathic lithic sandstone;the structural maturity was poor to moderate;the storage space was composed of intergranular pores and dissolution pores;the Chang 9₁section had the best development of pore throats and good physical properties,and then,the Chang 9₃section,the Chang 9₂section has poor physical properties,on the plane,the distribution of physical properties was consistent with the distribution characteristics of sedimentary microfacies and sand bodies.The reservoir quality was mainly controlled by sedimentation,diagenesis and microscopic pore structure characteristics.The underwater distributary channel microfacies had large sand body thickness,best physical properties,strong dissolution,large pore throat,good sorting and connectivity.The physical properties of estuarine dams and underwater natural embankments were moderate to poor,with similar development of dissolution and cementation,moderate pore throats,and moderate to poor sorting and connectivity.The physical properties,pore throat sorting and connectivity of the inter-distributary bay were poor.The Chang 9 could be divided into four types of reservoirs,with Class I high-quality reservoirs developed in the core of underwater distributary channels and relatively few overall;Class II good reservoirs were located in the main body of underwater distributary channels;Class III fair reservoirs were located at the edge of underwater distributary channels and in underwater natural embankments;Class IV poor reservoirs were located in the inter-distributary bay.Analyzing the reservoir characteristics and controlling factors in the research area can provide theoretical guidance for the rational exploration and development of Wanggoumen Oilfield in the later stage,and further improve the economic benefits of the oilfield.