Patent ID: 8616284

Claim:
A method for removing a residual polymer from a hydraulic fracture comprising not necessarily in this order: injecting a plurality of aliquots of viscoelastic surfactant (VES) gelled fluid into a subterranean formation, where a stop-start interval exists between the injection of each aliquot, where the viscoelastic surfactant gelled fluid comprises: water; and at least one viscoelastic surfactant in an amount effective to increase the viscosity of the water; contacting at least some of the residual polymer in the hydraulic fracture with the VES gelled fluid; reducing the viscosity of the VES gelled fluid with an internal breaker to form a broken fluid where the internal breaker is present in an oil-soluble internal phase of the water of the VES gelled fluid; and removing at least a portion of the residual polymer along with a majority of the broken fluid.