Study On The Control Mechanism Of Micro Pore Structure Of Tight Sandstone Reservoir To The Occurrence Of Tight Oil

With the exploration and development of conventional reservoirs becoming more and more advanced,tight reservoirs become the hot spot of future development.The reservoir characteristics of tight sandstone reservoir are complex,which affects the development of tight oil.In this paper,the pore structure characteristics of Chang 8 reservoir in study area are quantitatively characterized by core routine physical property test,field emission electron microscope scanning,thin section identification,movable fluid test,high pressure mercury injection and other experiments.On this basis,CT scanning and nuclear magnetic resonance technology are used to carry out the static experiment of tight oil occurrence and the dynamic experiment of oil displacement,and to analyze the occurrence state of tight oil.The key factors affecting the occurrence characteristics of tight oil are determined by correlation analysis between the experimental results and the micro pore characteristic parameters of the reservoir.The results show that Chang 8 reservoir has strong heterogeneity,poor physical properties and complex pore structure.Tight oil mainly occurs in the range of 0.001 ? m ~ 1.0 ? m pore throat radius,and the occurrence forms are oil film,cluster,porous and isolated.In the process of reservoir formation simulation of oil displacement water,oil always preferentially enters into medium pore throat and large pore throat.With the increase of injection volume,the oil content in small pore throat is also slowly rising,but the oil content in large pore throat and medium pore throat increases rapidly in small pore throat.Pore type,pore related parameters,throat parameters and pore throat combination are the key factors affecting the occurrence of tight oil.