A macroprocess to determine the direction and rate of the liquid-liquid interface within an oil-bearing reservoir has been considered. The process of oil displacement by water using the Hele-Show cell has been studied. It has been shown that an optimum filtration rate exists, which is determined by the equality of molecular surface and hydrodynamic forces. Use of water treated by surfactants and composite systems as displacement agents has shown that the Chuoke formula does not always provide reliable results. The possibility of evaluating the pumping rate during the process of downhole treatment has been shown.