Single Sand Body Carving And Well Network Adaptability Study For Low Permeability Reservoirs

Low permeability reservoirs are rich in reserves,but have poor natural properties,are difficult to develop and have low levels of extraction.A reasonable well network and well network parameters can effectively improve the development of low permeability reservoirs.Therefore,studying the adaptability of well networks and selecting reasonable well networks and well network parameters can effectively reduce the development cost of low-permeability reservoirs.To analyse and study the current issues of greatest concern for the development of low permeability reservoirs in an oilfield and to make rational recommendations,this thesis carries out the following research.The advantages of conventional piezometric tests,constant velocity piezometric tests,nuclear magnetic resonance,scanning electron microscopy,cast thin sections and CT scanning digital core techniques in terms of microscopic pore and throat structures are compared and analysed.The results and characteristics of the tests are used to gain a deeper understanding of the microscopic pore and throat structure and to study the microscopic seepage mechanism,reservoir oil-water reservoir state and seepage characteristics.The results show that the reservoir properties are mainly controlled by the throat channel,the pore types in the reservoir core are complex,with more small pores,and the oil-water reservoir state in the core is mainly influenced by the non-homogeneity of the pore structure.Based on CT scanning 3D digital core technology,the method and discriminatory model of reservoir classification are constructed to recognize and classify the reservoir structure of an oil field.Based on the inter-well pressure gradient field model and the start-up pressure gradient,a well spacing adaptability discrimination model for low permeability reservoirs was constructed to analyse the adaptability of the well spacing and well network in the field and establish an inter-well drive pressure system;to address the problem of poor reservoir physical properties in low permeability reservoirs and the difficulty in establishing an effective drive pressure system,an unequal production,one source,one sink injection and recovery model was used to derive and establish an inter-well The pressure gradient field model is used to determine whether an effective replacement pressure system is established between wells by combining the start-up pressure gradient and to analyse the adaptability of the inter-well distance of the well network.The water supply radius and oil recovery radius are calculated by integrating the injection and recovery pressure difference and reservoir flow rate to determine the limiting well spacing to guide the adjustment of well spacing in the field.Combined with the analysis of actual production data in the field,rational suggestions are made for the adjustment of well spacing in the well network,providing a theoretical basis for the efficient development of low permeability reservoirs.