Nonlinear waves and localized structures in two-phase flow through porous media

Three problems of two-phase flow through porous media are considered. In the first two flows in the region of near-critical saturations are investigated. Since under these conditions the active saturation and hence the phase permeability of one of the phases are small, it is important to take into account the delay in phase redistribution — such types of flow as nonlinear waves and localized structures become important. In the third problem it is assumed that the capillary jump is insignificant as compared with the phase pressures. It is shown that in this case localized structures may also occur.