Fracturing of subterranean formations

Abstract From the Canadian patent

Novel aqueous crosslinked gels are described herein which are useful for fracturing subterranean formations. The novel gels are comprised of a solvatable polysaccharide and a soluble zirconium crosslinking agent. The zirconium cross linking agents are novel and are prepared by reacting a zirconium alkoxide with certain alkanolamines under anhydrous conditions. The zirconium compounds are activated by contact with water. As an example a, zirconium crosslinker was prepared by reacting zirconium tetra(n-propoxide) with triethanolamine in an n-propanol solvent under anhydrous conditions. The zirconium compound thus prepared was activated with water and used to form a stable aqueous crosslinked …