Process for the selective controlled reduction of the relative water permeability in high permeability oil-bearing subterranean formations

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 an anionic 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 negative 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 anionic polymer aqueous solution towards the interior of the formation, whereby will be separated the slug of anionic polymer solution already injected and the slug of cationic polymer/cationic or non-ionic microgel suspension to be injected;
• c) injecting a slug of cationic polymer and cationic or non-ionic microgel suspension in a sufficient amount to form a layer of cationic polymer and said cationic or non-ionic microgel adsorbed to the anionic 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 displacement of the slug of cationic polymer/cationic or non-ionic microgel 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
• h) resuming well production.