Patent ID: 8739869

Claim:
A method for enhancing oil recovery from a subterranean formation, comprising: adding a first salt to a first aqueous stream to form a first injection stream with an increased concentration of a first ion; adding a second salt to a second aqueous stream to form a second injection stream with an increased concentration of a second ion, wherein the second injection stream is of substantially different composition than the first injection stream, and wherein the first injection stream and the second injection stream have substantially a same interfacial tension with a hydrocarbon and substantially a same kinematic viscosity; injecting the first injection stream into the subterranean formation at a first time; injecting the second injection stream into the subterranean formation at a second time, wherein the first injection stream and the second injection stream contact an overlapping portion of the subterranean formation; and recovering oil from the overlapping portion of the subterranean formation.