PETROLEUM FORMATION TREATMENT METHOD Russian patent published in 2020 - IPC E21B43/22 E21B33/138 C09K8/508 

FIELD: oil and gas industry.

SUBSTANCE: invention relates to oil industry and, in particular, to methods for increasing oil recovery from oil formations non-uniform in permeability. Proposed method comprises injection of invert emulsion consisting of oil or its processing products, tall oil, emulsion stabilizer and water with mineralization from 15 to 300 g/dm³. Invert emulsion additionally includes isopropyl alcohol, and stabilizer in invert emulsion is oxyethylated nonylphenol. Download invert emulsion is carried out in volume of 2-80 m³ at a predetermined component ratio, and using water with salinity of 15 to 300 g/dm³. After injection of 50% of the planned volume of the invert emulsion injection is discontinued and injection of the gelling agent is carried out in volume of 50-400 m³ comprising polyacrylamide, alumina, chromium acetate and water at a predetermined ratio of components. After pumping of gelling agent, pumping of remaining 50% of volume of invert emulsion is resumed and it is pumped into formation with water with mineralization of 0.5-300 g/dm³ in volume of 15 m³.

EFFECT: increased oil recovery, increased coverage of the formation by impact and reduced water content of the extracted product due to involvement of previously uncontrolled remote oil-saturated zones of the formation, high stability of the invert emulsion and broader technological capabilities of the method.

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