METHOD FOR OIL DEPOSIT DEVELOPMENT Russian patent published in 2016 - IPC E21B43/22 

FIELD: oil and gas industry.

SUBSTANCE: method comprises pumping into formation through an injection well a composition in form of aqueous solution of surfactants, an alkaline agent and a polymer. Pre-pumping into injection well a fringe of low-mineralised water to prevent formation of insoluble residue during reaction of said composition with formation water. Volume of said fringe is calculated depending on initial water mineralisation in formation by an analytical expression considering volume of fringe, pore volume of section of formation, water mineralisation of fringe, specific geological-physical conditions of deposit. Thereafter, said composition is pumped, wherein surfactant used is nonionic and anionic surfactants. Concentration of components in composition is taken in amount of 0.1-0.6 pore volume. Method then includes pumping fringe of polymer solution with viscosity equal to crude oil viscosity, in amount of 0.3-0.6 pore volume. Common flooding is then carried out. Pumping process is carried out without delay for impregnation.

EFFECT: increasing oil recovery factor from formation due to reduction of capillary forces, retaining residual oil.

1 cl, 2 tbl