Patent ID: 7084093

Claim:
A method for breaking viscosity of aqueous fluids gelled with polysaccharides comprising adding to an aqueous fluid gelled with at least one polysaccharide, at least one low molecular weight polyol; adding to the aqueous fluid in any sequence an effective amount of a metal ion to catalyze the polyol to break down the polymer backbone directly, where the metal ion is selected from the Periodic Table Groups VIB, VIIB, VIII, IB and IIB, where the metal ion is selected from the group consisting of: metal ions chelated or complexed prior to adding; metal ions that are a component of organometallic complexes; metals in oxide, sulphate, or phosphate form; metal ions plated onto particle surfaces; metal ions dispersed within a matrix; metal ions distributed within a synthetic porous particle; encapsulated or pelletized metal ions; and metal ions attached to the surface of clays; and in the absence of an oxidizer breaker.