FIELD: chemistry.
SUBSTANCE: invention relates to an inverse emulsion containing a cationic polymer which is stable under high salinity conditions. Reverse emulsion water-in-oil for preparation of fluid for hydraulic fracturing contains oil, water, water-soluble cationic copolymer with weight-average molecular weight of more than 3 million daltons, including from 18 to 32 mol.% cationic monomers and from 68 to 82 mol.%. non-ionic monomers, an inverting agent and an emulsifying agent, wherein the weight ratio R between the total amount of the inverting agent and the total amount of the emulsifying agent is more than 1.8. Inverting agent is selected from ethoxylated nonylphenol, ethoxylated/propoxylated alcohol, ethoxylated tridecyl alcohol and ethoxylated/propoxylated fatty alcohol and the emulsifying agent is selected from sorbitan monooleinate, polyethoxylated sorbitan esters or diethanolamide of tall oil fatty acids. Invention also relates to a method of producing fluid for hydraulic fracturing, to a method of hydraulic fracturing of an underground formation and to a method of reducing friction of the fluid for hydraulic fracturing.
EFFECT: obtaining an inverse water-in-oil emulsion of a certain composition with excellent operational characteristics relating to reduction of friction under conditions of very high salinity at high levels of content of divalent salts.
14 cl, 2 tbl, 9 ex
