Abstract: Changing concentrations of brine in a gravel pack carrier fluid gelled with a viscoelastic surfactant (VES) increases the fluid efficiency for gravel packing long interval wells, such as wellbore producing interval greater than about 100 feet (about 30 m). VES-gelled fluids used as gravel packing fluids herein also include surfactants, fluid loss control agents, internal breakers and brine in addition to the grave. The viscoelasticity of fluid system can suspend and deliver high concentration of the gravels while reducing carrier fluid volume.