Mobility control requirement in multiphase displacement processes in porous media

According to the conventional mobility control requirement, the displacing phase mobility (e.g. polymer) should be equal to or less than the sum of the mobilities of several displaced phases (e.g. water and oil). When the oil mobility is much lower than the water mobility, the sum of the displaced phase mobilities will be almost the same as the water mobility. Then, according to the requirement, the displacing polymer mobility is almost the same as the water mobility. As a result, the polymer solution will flow preferentially along water channels, leaving oil undisplaced. In this paper, we propose that the displacing phase mobility (polymer) should be equal to or less than the lowest mobility of displaced phases (generally, oil phase mobility) multiplied by its normalized saturation. This mobility requirement is validated by extensive simulation results at different conditions. It is also justified by field practices. Some published experimental data are analyzed to justify the proposed requirement. The proposed mobility requirement provides a criterion for mobility control design in multiphase displacement processes in porous media.