FIELD: chemistry.
SUBSTANCE: invention relates to extraction of hydrocarbons from underground formations. An aqueous composition containing a mixture of water, about 0.05-10 wt % of the total weight of at least one water-soluble block copolymer, containing: at least one block which is water-soluble by nature, which contains at least 34 wt % hydrophilic links relative the total number of links of the water-soluble block, and containing hydrophobic links and at least one hydrophobic block containing 67 wt % hydrophobic links relative the total number of links of the hydrophobic block, about 0.01-10 wt % of the total weight of a non-ionic surfactant with HLB value ranging from 1 to 12, and about 0.1-20 wt % of the total weight of at least one inorganic salt. The method of extracting hydrocarbons from underground formations involves feeding an aqueous fluid containing said composition into the formation. The method of forming cracks in an underground formation surrounding a well bore involves a step of feeding a fluid containing said composition into the well for hydraulic fracturing.
EFFECT: maintaining viscosity of aqueous solutions.
14 cl, 1 tbl, 2 dwg
