The efficiency of polymer enhanced oil recovery largely depends on the propagation of the injected polymer solution, which is mainly influenced by adsorption and mechanical entrapment of polymer. An efficient polymer displacement process is usually designed to maintain a stable front. The impact of mechanical entrapment on the front stability has as yet not been fully investigated. A quantitative evaluation requires accurate solutions of the relevant two-phase flow equations considering adsorption and a history-dependent entrapment function.The model equations for single phase flow need to solved first and can be used to obtain a few model parameters by comparison to available experimental data. These equations are solved analytically, which yields 1-D concentration and saturation profiles considering both adsorption and entrapment. In addition the pressure history of the displacement process is obtained. The ensuing polymer concentrations with and without entrapment are then considered for the design of the mobility control for a polymer EOR process.We find that by inclusion of mechanical entrapment, the polymer concentration reduces from the injection point towards the displacement front. The severity of the concentration loss at the front is indicated by the history of the previously entrapped polymer molecules.Conditions can be chosen to sufficiently reduce the mobility ratio between the polymer and the oil and can show under which conditions the oil can be displaced in a stable manner.
