Method for increasing the stability of water-based fracturing fluids

摘要

A method for increasing the stability of water-based fracturing fluids is shown in which a base fracturing fluid is formulated by mixing together a hard mix water containing multivalent cations, a water soluble polymer and a cross-linking agent for the water soluble polymer. A water softener is added to the base fracturing fluid which hinders the ability of the multivalent cations present in the hard mix water to compete with the water soluble polymer for borate based cross-linking agent, thereby stabilizing the resulting fracturing fluid.