Abstract: Subterranean formations are fractured by use of an aqueous fracturing fluid containing an effective amount of a copolymer of acrylamide and potassium acrylate crosslinked with a titanium or zirconium compounds. The fracturing fluid also contains an oxidative gel breaker. The method is particularly suited for treatment of deep, high temperature formations.

Abstract: A method of fracturing a subterranean formation involving the use of crosslinked gels to form a fracture and deposit particulate proppant therein followed by the introduction of dilute aqueous solutions of chlorine dioxide in the propped fracture to degrade the gel.

Abstract: A rotational molding process for slush casting mold with plastisol includes providing a conveyor having a plurality of spaced reversing arm assemblies, each arm assembly having opposite ends carrying molds thereon; providing first and second conveyor paths for the molds on the opposite ends of each arm assembly and locating one of the first and second conveyor paths inside the outer perimeter of the other of the first and second conveyor paths; preheating a mold on one of the arm assemblies on the first conveyor path and filling the preheated mold with an excessive charge of plastisol to form a gel layer thereon while on the first conveyor path and thereafter dumping plastisol from the preheated mold for return to a supply source of plastisol; and simultaneously curing a gel layer on another of the arm assemblies by directing the mold through the second conveyor path as the preheated mold on the other end of the arm assembly is being filled and dumped whereby the movement of an arm assembly produces simultane

Abstract: A mixture of dry ingredients capable of forming a crosslinked polymer upon hydration for use as a fracturing fluid in processes for recovering minerals from subterranean formations. The dry mix comprises a polysaccharide, a crosslinking agent selected to become active after the polysaccharide has been substantially hydrated, and a pH-adjusting agent to facilitate the crosslinking reaction. The mix is hydrated while being pumped and reaches maximum viscosity in the subterranean formation.