OIL RECOVERY METHOD Russian patent published in 2019 - IPC C09K8/584 C09K8/60 E21B43/22 

FIELD: oil, gas and coke-chemical industries.

SUBSTANCE: present invention relates to method of oil recovery from underground oil deposits. Method of obtaining by means of carboxymethylation of a mixture of surfactants for use in oil production, containing at least one anionic surfactant (A) of the given general formula, obtained by reacting a nonionic surfactant (B) of the general formula given under said conditions. Concentrate with said surfactant mixture (A) and (B) containing 20–70 wt. %. of said surfactant mixture, 10–40 wt. % water and 10–40 wt. % of additional solvent selected from said group, and is fluid at 20 °C, and at 40 °C having viscosity less than 1500 MPa at 200 Hz. Method of extracting oil from underground deposits, wherein at least through one injection well, an aqueous salt-containing surfactant composition is injected into deposit and at least one crude oil is extracted through at least one production well, wherein said conditions use, at injection, said surfactant (A) and (B) mixture or said concentrate. Invention is developed in dependent items of the formula.

EFFECT: technical result is higher efficiency of treatment of underground deposit.

26 cl, 6 tbl