SOLUBILITY ENHANCERS BASED ON ALLYL ALCOHOL FOR AQUEOUS COMPOSITIONS OF SURFACTANTS FOR ENHANCING OIL EXTRACTION Russian patent published in 2022 - IPC C09K8/584 E21B43/22 

FIELD: oil industry.

SUBSTANCE: group of inventions relates to the extraction of crude oil from underground oil-bearing reservoirs. A method for the extraction of crude oil from underground oil-bearing reservoirs includes: providing an aqueous composition containing water and a surfactant mixture, injecting the specified composition into an underground oil-bearing reservoir through at least one injection well, reducing the tension at the interface of crude oil-water to less than 0.1 mN/ m, and extracting crude oil from the reservoir through at least one producing well. The surfactant mixture contains at least surfactant (A) with the general formula and a solubility enhancer (B) with the general formula where R¹ is a hydrocarbon fragment with from 8 to 36 carbon atoms, R² is a hydrocarbon fragment with from 2 to 16 carbon atoms, R³ is selected from a simple bond group, an alkylene group -(CH₂)_o-, where o is from 1 to 3, a group -CH₂-CH(OH)-CH₂-, R⁴ is an allyl group H₂C=CH-CH₂-, Y^- is an anionic group selected from -COO^- or -SO₃^-, M⁺ is at least cation selected from a group: H⁺, alkali metal ions, NH₄⁺, and organic ammonium ions, a is a number from 0 to 69, b is a number from 3 to 70, c is a number from 0 to 50, x is a number from 1 to 69, y is a number from 0 to 50, and where R³, Y^- and M⁺ in (A) and (B) are identical, x<b, y=c, and the molar ratio of surfactant (A)/solubility enhancer (B) is from 98:2 to 60:40.

EFFECT: good solubility of surfactants for increasing oil extraction in reservoir water at a reservoir temperature, reduction in the surface tension at the interface between crude oil and reservoir water to a level of less than 0.1 mN/m.

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