Patent ID: 8550164

Claim:
A process for recovering hydrocarbons in a carbonate reservoir, the process comprising the steps of: (a) introducing a first saline solution into the carbonate reservoir, wherein the first saline solution has a first salt concentration, wherein the first saline solution comprises water, salt, and an absence of a surfactant; (b) recovering an amount of hydrocarbon from the carbonate reservoir; (c) introducing a second saline solution into the carbonate reservoir, wherein the second saline solution has a second salt concentration that is lower than the first salt concentration, wherein the second saline solution comprises water, salt, and surfactant; (d) introducing a third saline solution into the carbonate reservoir, wherein the third, saline solution has a third salt concentration that is tower than the first salt concentration, wherein the third saline solution comprises water and salt; and (e) recovering a second amount of hydrocarbon from the carbonate reservoir.