Patent ID: 7527102

Claim:
A method for directed placement of acid in a subterranean formation comprising: introducing a viscoelastic surfactant gelled fluid into a subterranean formation, where the viscoelastic surfactant gelled fluid comprises: water; at least one viscoelastic surfactant (VES) in an amount effective to increase the viscosity of the water; and at least one internal breaker selected from the group consisting of bacteria, transition metal ion sources, saponified fatty acids, mineral oils, hydrogenated polyalphaolefin oils, saturated fatty acids, unsaturated fatty acids and combinations thereof; and subsequent to introducing the VES gelled fluid, introducing an acid into the subterranean formation to place it as at least partially directed by the VES gelled fluid; and reducing the viscosity of the VES gelled fluid with the internal breaker.