SULFOSUCCINATE SURFACE-ACTIVE MIXTURES AND METHODS FOR USE THEREOF Russian patent published in 2021 - IPC C09K8/584 

FIELD: oil and gas industry.

SUBSTANCE: invention relates to compounds of sulphosuccinate surfactants, mixed in two- and three-component compositions to obtain synergetic mixtures of sulphosuccinate surfactants, and their use in methods of increasing oil recovery of formation and hydraulic fracturing of formation. Mixture of surfactants for oil production contains a mixture of: (a) one or more first compounds of diester-sulphosuccinate surfactant according to formula (I): R¹-O-CO-CHX-CHY-CO-O-R² (I) where: R¹ and R² are linear or branched alkyl groups, each of which independently contains from eight to thirteen carbon atoms, X is -H or -SO₃⁻M⁺, and Y is -H or -SO₃⁻M⁺, if X is -H, then Y is -SO₃⁻M⁺, and if Y is -H, then X is -SO₃⁻M⁺, where M⁺ is H⁺, Na⁺, Ca²⁺, Mg²⁺, K⁺, NH₄⁺, NR₄⁺, where R is H, methyl, ethyl, propyl or butyl. And another component of mixture - (b) of one or more first compounds of monoester-sulphosuccinate surfactant according to formula (III): B⁺ -O-CO-CHX-CHY-CO-O(CH₂-CH₂-O)_z-R⁵ (III) where: B⁺ is Na⁺, K⁺, Ca²⁺, Mg²⁺, NH₄⁺ or NR₄⁺, where R is H, methyl, ethyl, propyl or butyl, X is as defined for formula (I), Y is as defined for formula (I); and Z equals 0–30, and R5 is a linear or branched alkyl group containing from eight to twenty carbon atoms (C8-C20). Method of using said surfactant mixture for oil production involves combining their effective amount with brine to form a solution; pumping of effective amount of solution into underground reservoir and increase of pressure in underground reservoir thus ensuring oil extraction from underground reservoir.

EFFECT: technical result is higher efficiency of oil extraction due to reduction to ultra-low values of tension at interface boundary, which will facilitate oil release.

10 cl, 8 tbl, 1 ex