Research About The Nonlinearity Filtering Flow In Extra-high Watercut Stage

China's major land on the old oil fields have entered the late development of water injection.Due to the long-term erosion of the injected water and the heterogeneity of the reservoir,the advantage seepage channel gradually formed and greatly affected the production capacity of the oil field.When the oil field was in the high water cut period,the flow law did not simply accord with the linear seepage law.In this paper,the formation and development of the advantage seepage channel are analyzed,and the relationship between the existing linear and nonlinear flow and the relationship between the flow state and the resistance are summarized.On this basis,the highspeed non-Darcy physical simulation experiment is carried out,and the similarity criterion is used to establish the physical Simulation model.The influence law of the high-speed non-Darcy flow in the dominant channel and the critical value of the Reynolds number Re are analyzed,and the corresponding mathematical equation is established.Based on this,a one-dimensional radial flow mathematical model was established.The curves of bottom hole pressure distribution under different seepage flow and seepage flow were obtained,and the influence of nonlinear seepage was analyzed.In addition to the formation of the advantage channel,long-term waterflooding has also led to the continuous improvement of the water content of the effluent.The movement of the underground liquid is mainly water flow,and the simple oil-water two-phase or water singlephase seepage does not accurately describe its flow In this paper,the relative relationship between oil saturation and pressure gradient under high water content is analyzed by carrying out the physical simulation experiment of sand filling pipe.The oil pressure starting point is proposed,and the permeability of the model is studied qualitatively.The effect of crude oil viscosity and medium particle size on it,and then the results were verified by artificial core simulation experiment.According to the experimental results,a two-dimensional mathematical model of two-dimensional oil-water two-phase is established,and the influence on the remaining oil distribution is analyzed and the theoretical guidance is given to the remaining oil development.