Patent ID: 7563750

Claim:
A method comprising: performing an injection operation in a subterranean formation penetrated by at least one injection well and at least one production well, wherein the injection operation comprises: introducing a water-soluble relative permeability modifier comprising a hydrophobically modified water-soluble polymer through at least one injection well into a first zone of the subterranean formation having a permeability to aqueous-based fluids so that the hydrophobically modified water-soluble polymer reduces the permeability of the first zone of the subterranean formation to aqueous-based fluids, wherein the hydrophobically modified water-soluble polymer has a molecular weight in the range of about 100,000 to about 10,000,000 once synthesized and comprises a polymer backbone and a hydrophobic branch, the hydrophobic branch comprising an organic acid derivative selected from the group consisting of: an anhydride of octenyl succinic acid, an ester of octenyl succinic acid, an amide of octenyl succinic acid, an anhydride of dodecenyl succinic acid, an ester of dodecenyl succinic acid, and an amide of dodecenyl succinic acid; and injecting an aqueous injection fluid through at least one injection well into the first zone of the subterranean formation after introducing the water-soluble relative permeability modifier so that the hydrophobically modified water-soluble polymer present in the first zone of the subterranean formation diverts at least a portion of the aqueous injection fluid to a second zone of the subterranean formation.