SELECTIVE EMULSION COMPOSITION FOR WATER INSULATION AND ALIGNMENT OF PRODUCTION WELL INFLUX PROFILE Russian patent published in 2020 - IPC E21B33/138 C09K8/502 E21B43/32 

FIELD: chemistry.

SUBSTANCE: invention relates to compositions for limiting water influx during repair of oil and gas wells, as well as when leveling the profile of inflow of production wells when pumping it into injection well and elimination of absorption of flushing liquid when drilling wells using solutions on hydrocarbon base (SHB). Selective emulsion composition contains a hydrocarbon liquid, a calcium chloride solution, esters of fatty acids. Ester of fatty acids contains a mixture of modified esters of fatty acids and polyatomic alcohol. Calcium chloride solution is used in the form of a solution with density of 1.06–1.32 g/cm³. Composition additionally contains oleic acid, a direct emulsion which is an aqueous dispersion of colloidal particles of copolymers of styrene and/or butadiene, stabilized with ionic surfactants, and marble chips, with the following ratio of components, wt%: hydrocarbon fluid 23.5–74.3; oleic acid – 0.4–1.7; mixture of modified ethers of fatty acids and polyatomic alcohol – 1.7–7.9; said direct emulsion – 1.6–15.8; marble chips – 0.5–30.2; said solution of calcium chloride is the rest.

EFFECT: reduced permeability of the productive reservoir in water with preservation of selective properties due to increased structural-mechanical properties in time during contact with water, reduced wash-out and increased residual resistance to movement of water in the porous space of the collector.

3 cl, 2 ex, 2 tbl