Methods and compositions are disclosed for controlled addition of components that decrease the viscosity of the viscoelastic surfactant fluids or for controlled changes in the electrolyte concentration or composition of the viscoelastic surfactant fluids. One aspect of the invention relates to the use...http://www.google.com/patents/US6908888?utm_source=gb-gplus-sharePatent US6908888 - Viscosity reduction of viscoelastic surfactant based fluids
