The Research Of Relative Permeability Curves Of Polymer Flooding Based On Digital Pore Model

The phase permeability curve of polymer flooding is an important parameter in the process of polymer flooding,and the acquisition of relative permeability curve is an important task faced by oilfield workers.The traditional methods of indoor experimental acquisition have some shortcomings,such as long time,high cost and poor repeatability.Using the digital pore network model to simulate the process of polymer flooding and obtain the phase seepage curve,which can provide rapid and powerful support for the further study of the process of polymer flooding and the improvement of the recovery rate.In this paper,based on the basic structural parameters of reservoir rocks,the pore throat ratio,coordination number and shape factor are considered,and the complex pore throat channels are described by the corrugated tubular structure.The digital pore model based on the adaptive porosity method conforms to the actual core structure.Based on the principle of fluid mechanics and percolation mechanics,the mathematical model of saturated oil process and polymer flooding process is established by cons idering the wettability of reservoir rock,rheological properties of polymer,adsorption property and void volume,and the mathematical integration and iterative equation are used to describe the polymer solution in the digital pore network model.The rela tive permeability of polymer flooding was calculated and the effects of pore structure parameters and polymer characteristics on the permeability curve were studied.The results show that the constructed digital pore network model matches the reservoir rock,and the calculated permeability curve is basically consistent with the experimental curve.The digital pore model can fully reflect the influence of pore structure parameters and polymer characteristics on the permeability curve of polymer flooding.The pore throat ratio is small,the coordination number is large,the shape factor is large,the oil phase relative permeability curve is high,the relative permeability curve of the polymer phase is low,the two phase co flow area is large and the residual o il saturation is low.The polymer concentration is high,the molecular weight is large,the relaxation time is long,the oil phase relative permeability curve is high,the isotonic point moves to the right side,and the residual oil saturation is low.Cons idering the polymer adsorption characteristics,the relative permeability of polymer phase is high and the isotonic point moves to the left side.Considering the influence of polymer pore volume,the relative permeability curve of oil phase is high,the relative permeability curve of polymer phase is low,and the residual oil saturation is low.This indicates that the digital pore model is feasible for obtaining the phase permeability curve of polymer flooding.