FIELD: special-destination fluids. SUBSTANCE: invention relates to viscous aqueous fluid possessing elastic properties and used as thickener in water-based hydraulic fluids, for example in hydraulic breaking fluids in oil-production wells. Surfactants contained in viscoelastic fluid are of zwitterion/amphoteric nature such as dihydroxyalkyl glycinates, alkyl amphoacetate or propionate, alkyl betaine, alkylamidopropyl betaine, and alkylamino mono- or dipropionates obtained from waxes, fats, and oils. Thickening agent is used in combination with water-soluble inorganic salt or organic additive such as phthalic acid, salicylic acid, or their salts. Zwitterionic surfactant represents 77% and more of the weight of all surfactants and 0.5 to 10% of the total weight of fluid. EFFECT: improved viscosity characteristics in dependence of shear thrust. 99 cl, 5 dwg, 5 tbl, 10 ex
