Considering the absorbing factor and inaccessible pore

a five-spot well pattern model of polymer flooding was built on the base of polymer flooding mechanism analysis.By applying the stream tube method

the areal two-dimensional model was simplified to several one-dimensional displacement models

and a one-dimensional mathematical model of polymer flooding was established.On the basis of frontal displacement theory

the whole process of two-dimensional polymer flooding was simulated by superimposing the displacement performance in each stream tube on the five-spot well pattern.This calculation process was compiled into the VBA software to map the relation between the sweep efficiency and mobility ratios under different water cut conditions are draw

thus providing a theoretical criteria for the polymer solution viscosity preparation when performing IOR through polymer flooding.Comparison between the dynamic parameters with the experimental results shows a good consistency.The advantages of the stream tube model set up in this paper are as follo-wing:less input parameters

quick calculation

well-adapting

and no dispersion effect of numerical simulation as in the traditional rectangular grid.Therefore

this method offers an effective tool for the early selection for polymer flooding and reservoir dynamic management.