FIELD: physics.
SUBSTANCE: invention relates to a composition and methods for delayed liquefaction with respect to gels of viscoelastic surfactants within subterranean formations. Dilution is performed without mechanical intervention or use of the second fluid medium. Composition comprises an aqueous fluid, a viscoelastic surfactant, a delayed-action delay agent is selected from alkyl ether phosphates and salts thereof, alkylaryl ether ethers and salts thereof, alkyl sulphates and salts thereof, alkylaryl sulphates and salts thereof, alkyl ether sulphates and salts thereof, alkylaryl ether sulphates and salts thereof and mixtures of any of said compounds. Method of treating a subterranean formation comprising a wellbore comprises providing said composition, injecting it into a subterranean formation, where it is present in form of a viscous fluid medium, and possibility of action of fluidising agent on viscous fluid medium with reduction of its viscosity. Above composition is used in treating a subterranean formation as a diluting medium for the composition of a viscoelastic surfactant.
EFFECT: technical result is the increase in the treatment efficiency.
13 cl, 8 dwg, 8 ex
