METHOD FOR INCREASING OIL RECOVERY OF RESERVOIRS BY EXPOSURE TO AN ALKALINE SOLUTION OF A SURFACTANT Russian patent published in 2022 - IPC E21B43/22 E21B33/138 C09K8/584 C09K8/42 

FIELD: oil industry.

SUBSTANCE: invention relates to the extraction of oil by displacing it from a terrigenous and carbonate productive reservoir with a viscous aqueous alkaline solution of zwitterionic surfactants. In the method for increasing oil recovery of reservoirs by exposure to an alkaline solution of a surfactant, fresh water is first injected into the reservoir in an amount of 0.01-5% of the pore volume; then an alkaline technological solution is injected in an amount of 0.1-5% of the pore volume, consisting of, wt. %: a zwitterionic surfactant from the series oleyl amidopropyl dimethyl-betaine, or cocamidopropyl betaine, or alkyl sulfobetaine, or alkyldimethylaminoxide 0.5-10; sodium silicate 0.5-15; sodium chloride 0-25; a component from the series sodium hydroxide, potassium hydroxide, sodium carbonate, sodium bicarbonate 0.05-10; water the rest; then fresh water is pumped in an amount of 0.01-5% of the pore volume; then a technological solution is injected in an amount of 0.1-5% of the pore volume, consisting of, wt. %: a zwitterionic surfactant from the series oleyl amidopropyl dimethyl-betaine, or cocamidopropyl betaine, or alkyl sulfobetaine, or alkyldimethylaminoxide 0.5-5; reservoir water the rest; then water is pumped to maintain reservoir pressure.

EFFECT: increase in the coverage of reservoirs by flooding, the elimination or reduction of the negative influence of the forces holding oil in the flooded areas of the formation, a decrease in the permeability of the flooded areas.

1 cl, 2 dwg, 21 ex