Change to Low Salinity Brine Injection in Combination with Surfactant Flooding

It is known that surfactant flooding can be efficient when using a salinity gradient. A gradual reduction in<br>salinity with time controls the surfactant phase behaviour, and ensures minimum interfacial tension (IFT)<br>to be achieved within the salinity gradient. The surfactant ends up as oil in water microemulsion in the low<br>salinity water chasing the surfactant slug.