The Use of Second-Order Godunov-Type Methods for Simulating EOR Processes in Realistic Reservoir Models

Enhanced oil recovery using polymer or chemical flooding involves the displacement of oil by slugs with dynamic behavior critical to the response and the efficiency of the process. The numerical modelling of these processes is very difficult, since the dynamics of the slug flow lead to concentration fronts that are not self-sharpening. Conventional upstream-weighted finite differences lead to both substantial grid orientation errors and to smearing of sharp fronts. This paper reports the formulation and performance of a second-order Godunov-type finite difference method for modelling of two-dimensional (2-D), three-component incompressible polymer floods. The scheme successfully handles realistic applications and significantly reduces both the spreading of fronts and grid orientation effects, when compared to the standard upstream-weighted finite difference schemes. Polymer slug injection examples will be shown for both areal and cross sectional models involving various reservoir heterogeneities and realistic reservoir models. Also, a one-dimensional (1-D) example is given.