ABSTRACT
The paper presents a study on the restoration of permeability of the bottomhole formation zone after intervasion of the filtrate of drilling flushing fluid. The author conducted a study on samples of natural core using clay, potassium chloride, polymer clay and polymer flushing fluids. The theoretical part of the study is devoted to the choice of flushing fluid based on the saturation and radius of its invasion into the reservoir. These parameters are determined by calculation based on the theory of two-phase filtration. The formula for the distribution of phase fluxes with regard to capillary pressure is derived and its effect on the saturation and the radius of the filtrate invasion are established. A link has also been established between the restoration of permeability and interfacial tension at the interface of oil and water filtrate.
