Foamed treatment fluids comprising water, a gas, and a foaming and foam stabilizing surfactant mixture comprising an alkali salt of an alkyl ether sulfate, wherein the alkali salt of the alkyl ether sulfate comprises an alkali salt of a C.sub.6-10 alkyl ether sulfate, and an alkali salt of a C.sub.4 alkyl ether sulfate, an alkyl amidopropyl amphoteric surfactant selected from the group consisting of an alkyl amidopropyl hydroxysultaine, an alkyl amidopropyl betaine, and combinations thereof, and an alkyl amidopropyl dimethylamine oxide. Methods comprising providing the foamed treatment fluid and introducing the foamed treatment fluid into a subterranean formation.
A method is described for treating a subterranean formation with a low viscosity fluid system that contains a viscoelastic surfactant at a concentration too low to viscosify the fluid, but that is concentrated in the formation so that the fluid system gels. The fluid also contains a formation-dissolving agent. The fluid is used in acidizing, acid fracturing, and diversion.
