| abstract |
A low viscosity wellbore polymer fluid gelling system comprising an aqueous medium and a water-in-water emulsion comprising a plurality of polymers or oligomers, including at least one removable polymer or oligomer, and at least one gelling polymer or oligomer, wherein said fluid has a low viscosity when injected, and the gelling polymer forms a gel downhole which has a storage modulus of at least about 60 Pa after the removable polymer is removed from the fluid. The invention also provides a method of isolating at least one zone of a subterranean formation penetrated by a wellbore, including the steps of preparing a water-in-water emulsion comprising a plurality of polymers or oligomers including at least one removable polymer or oligomer, and at least one gellable polymer or oligomer; combining the water-in-water emulsion with an aqueous medium to prepare a low viscosity polymer fluid; introducing the fluid into a zone in the formation, removing the at least one removable polymer or oligomer, and allowing a remaining gellable oligomer, polymer or polymers to form a gel, isolating the zone from at least one other zone in the formation. |