Fractional-Flow Theory of CO2 Foam Displacements with Surfactant Dissolved in the CO2

A foam process with surfactant dissolved in supercritical CO2 has the advantage that injection of CO2,<br>once begun, need never be interrupted for surfactant injection in water. In addition, CO2 can carry<br>surfactant to layers that may not be swept by an aqueous surfactant slug. CO2 carries the surfactant and<br>forms foam with water in the formation.