Patent ID: 7387987

Claim:
An oilfield treatment method of fracturing, gravel packing or fracturing and gravel packing comprising: a. viscosifying a fluid with a viscoelastic surfactant system comprising a viscoelastic surfactant selected from at least one of zwitterionic, amphoteric, and cationic surfactants and mixtures thereof, said fluid having an entangled wormlike micelle structure, b. adding to said fluid from about 0.005 to about 0.5 weight % of a rheology enhancer, thereby increasing viscosity of said fluid, and decreasing shear rehealing time of said fluid, said rheology enhancer selected from the group consisting of polypropylene glycols and block copolymers of polypropylene glycol and polyethylene glycol; and c. injecting said fluid down a well, further comprising shearing the viscosified fluid to disrupt the micelle structure and then reducing shear for said rehealing.