Systems and methods for enhanced waterfloods

摘要

Methods for enhanced oil recovery from a subterranean formation including adding a first salt to a first aqueous stream to form a first injection stream with an increased concentration of a first ion. A second salt is added to a second aqueous stream to form a second injection stream with an increased concentration of a second ion. The second injection stream is of different composition than the first injection stream and the first injection stream and the second injection stream have substantially the same interfacial tension with a hydrocarbon and substantially the same kinematic viscosity. The first injection stream is injected into the formation at a first time and the second injection stream is injected into the formation at a second time. The first injection stream and second injection stream contact at least some overlapping portion of the formation. Oil is recovered from the overlapping portion of the formation.

主权项

1. 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.