Patent ID: 7395858

Claim:
A process for the selective and controlled reduction of permeability to water of high permeability oil-bearing subterranean formations and temperature up to 110° C. traversed by a well for the production of oil and/or gas, wherein said process comprises, for said well the following steps: a) injecting a slug of a cationic polymer aqueous solution in the amount required for adsorption at a certain penetration radius in said subterranean formation, a portion of said aqueous solution creating a polymer adsorbed to the formation and containing free positive residual charges, while another portion remains non-adsorbed and can be displaced by successive brine and polymer/microgel slugs up to the required penetration radius; b) injecting a spacer slug of an aqueous brine solution, so as to displace said non-adsorbed portion of the slug of aqueous cationic polymer solution towards the interior of the formation, whereby will be separated the slug of cationic polymer solution already injected and the slug of anionic polymer/anionic or non-ionic microgel suspension to be injected; c) injecting a slug of anionic polymer and anionic or non-ionic microgel aqueous suspension in a sufficient amount to form a layer of anionic polymer and said microgel adsorbed to the cationic polymer layer already adsorbed to the subterranean formation rock; d) injecting a spacer slug of an aqueous brine solution for spacing the polymer slugs and displacing the slug of anionic polymer/anionic or non-ionic microgel aqueous suspension towards the interior of the formation; e) if required, repeating the treatment sequence a), b) and c) until the injection pressure of the aqueous solution of step d) attains a value such as to reach the desired value of Residual Resistance Factor to water (RFFw); f) shut-in the well during the required period of time to finish the adsorption process among the layers; and g) resuming well production.