PERMEABILITY OR FLUID MOBILITY REDUCTION TREATMENT FOR A HYDROCARBON-BEARING FORMATION USING A DUAL MOLECULAL WEIGHT POLYMER GEL

摘要

A process is provided for reducing the permeability of or fluid mobility within a high-temperature treatment region in or proximate to a hydrocarbonbearing formation below an earthen surface penetrated by a well bore. The process is initiated by preparing a gelation solution at the earthen surface which includes a base loading of a high molecular weight acrylamide polymer, an additive loading of a low molecular weight acrylamide polymer, a crosslinking agent, and an aqueous solvent. The crosslinking agent is preferably a chromium(III) complex having one or more chromium(III) cations and one or more carboxylate anions. The resulting gelation solution is injected into the well bore and displaced into the treatment region where it is gelled in situ to form a gel which substantially reduces the permeability of or fluid mobility within the treatment region.