US Patent 10472555 Polymer gel for water control applications

A method for reducing a permeability of at least one zone in a subterranean formation that includes introducing a treatment fluid to at least one permeable zone in a subterranean formation. The treatment fluid contains a solvent, a crosslinking agent, and a water-soluble polymer that is a copolymer of an acrylamide monomer and an n-vinyl amide monomer, or a terpolymer of an acrylamide monomer, an n-vinyl amide monomer, and an acrylic-acid based monomer. The treatment fluid is then allowed to crosslink and form a gel in the zone.