Method and composition for reducing the permeability of a high-permeability zone in an oil reservoir

Abstract From the Canadian patent

A method for reducing the permeability of a high-permeability zone in a high-temperature oil reservoir comprises: - preparing a gellable polymeric aqueous solution operating on, the surface under controlled conditions; - injecting said gellable solution into the oil reservoir through a well;, - moving the solution through the reservoir until it reaches and substantially fills the high-permeability zone to be treated; and - gelling the solution in situ with consequent lowering of the permeability in said high-permeability zone and is essentially characterised in that the gellable solution is an aqueous solution containing a Cr(III) ion cross-linking agent and a water-soluble organic polymer …