Method for reducing formation permeability and compositions for use in the method.

摘要

A method for reducing formation permeability comprising mixing (a) a homopolymer or copolymer of methyl acrylate or hydroxy alkyl acrylate, where the alkyl group is C<Sub>2</Sub>, C<Sub>3</Sub> or C<Sub>4</Sub>, into which polymer hydrazide groups have been introduced, and (b) an aldehyde cross-linking agent, dispersing the mixture in an aqueous medium and injecting the aqueous dispersion into a formation, the amounts of the polymer and aldehyde being such that they will form a gel in the aqueous medium. The invention includes compositions for use in the method.