METHOD OF TREATING NON-UNIFORM PERMEABILITY OIL RESERVOIR BY INJECTION OF INVERT EMULSION Russian patent published in 2018 - IPC E21B43/22 C09K8/92 

FIELD: oil and gas industry.

SUBSTANCE: invention relates to the development of oil fields and can find application in the development of an oil reservoir with heterogeneous permeabilities of flooded layers for regulating the input profile of a well and limiting the water inflow in the production well by equalizing the permeability heterogeneity of the formation. In the method for treating a non-uniform permeability oil reservoir by injection of an invert emulsion obtained by mixing the emulsifier and an aqueous solution in a certain proportion, an emulsifier consisting of an oxyethylated alkylphenol AF₉-6 and oleic acid in a ratio of 2:1, as well as a benzene-containing fraction, the total concentration of oxyethylated alkylphenol AF₉-6 and oleic acid in the emulsifier is 15–39 %, the rest is a benzene-containing fraction, as an aqueous solution, mineral water is used, before injecting the emulsion determine the allowable injection pressure and injectivity of the well, with injectivity below 250 m³/day emulsifier is mixed before pumping with mineralized water in a volume ratio of 2:1, and when the injectivity is above 250 m³/day – in a ratio of 1:2, with the injection in both cases conducted with pressure control, when the injection pressure is increased by 1.1–1.2 times from the initial pressure, the volume ratio of mineralized water in the emulsion is doubled to a ratio of 1:4, with a further increase in pressure of 1.1–1.2 times the ratio is increased to 1:10 and then successively doubled to 1:40, while the injection pressure should not exceed 0.95 of the allowable pressure.

EFFECT: increased formation coverage due to more uniform distribution of the emulsion along the reservoir, increased aggregative stability of the invert emulsion and improved rheological properties of the injected emulsion.

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