Study On The Polymer Flooding Numerical Simulation Considering The Dynamic Relative Permeability Curve

So far,the majority of maturing oil fields of China have already entered into the stage of high water cut.But there is still a mass of oil getting stuck in the reservoirs.Polymer flooding which is one of the means of enhanced oil recovery can reduce water cut while increasing the oil recovery and has a wide application.Vast studies have found that there is a change in the oil-water phase relative permeability curve(O-WPRP curve)during the polymer flooding process.In some commercial reservoir numerical simulation software,in order to correct the water phase permeability,the permeability reduction coefficient is applied.However,in addition to the water phase relative permeability,the oil phase relative permeability and the two ends of the O-WPRP curve will also change.In other words,the O-WPRP curve is always in a dynamic changing process.If this overall dynamic changing process is not considered in the numerical simulation,the final calculation result will not be close to the reality,which will affect the related polymer flooding history matching and remaining oil analysis.Therefore,this paper begins with the analysis of features of the dynamic O-WPRP curve in polymer flooding.Then,an interpolation method which is based on the normalized polymer concentration is proposed to characterize the dynamic change of the O-WPRP curve with the concentration change during the polymer flooding process.After that,a mathematical model for polymer flooding coupled with the dynamic relative permeability curve is established,solved by finite difference and fully implicit methods,and related polymer flooding simulation software was compiled,and its rationality and engineering applicability were verified.The sensitivity analysis of the dynamic relative permeability curve is conducted based on this complied software.Sensitivity analysis shows that after considering the dynamic change,the “funnel” of the calculated water cut is lower,the “hump” of the daily oil production rate is higher,and the oil recovery is increased,which can better describe the changes in oil-water flow capacity during the polymer flooding.And the compiled software is also applied to the history matching work of the target polymer injection well group in Z oilfield.And the calculation result has a higher matching accuracy than ECLIPSE,which further illustrates the rationality and application significance of the research content in this paper.