(201h) CO2 Foam Stabilization using Zwitterionic and Nonionic Surfactants

Selection of surfactant for enhanced oil recovery and other upstream applications is a challenging task. For upstream foaming applications, it should be thermally stable, compatible with reservoir brine and other chemicals, have lower adsorption on reservoir rock, has high foamability and foam stability, and should be economically viable. In this work, Foamability and foam stability of three different surfactants were evaluated using dynamic foam analyzer. These surfactants were fluorinated nonionic, fluorinated zwitterionic, and hydrocarbon zwitterionic surfactants. Effect of surfactant type and structure, concentration, temperature, polymer additions, salt addition, and type of injected gas was investigated on foamability and foam stability. The foamability was assessed using the volume of foam produced by injecting a constant volume of gas and foam stability was determined by half-life time. The maximum foam generation was obtained using hydrocarbon zwitterionic surfactant. However, the foam generated using fluorinated zwitterionic surfactant was more stable. A mixture of solution containing zwitterionic fluorinated and hydrocarbon fluorinated surfactant showed better foam generation and foam stability. The foam generated using CO₂ has less stability compared to the foam generated using air injection. Addition of polymer significantly improved the foam stability and have no effect on foam generation. Presence of salts increases the foam stability and foam generation. This study helps in optimizing the conditions of foam injections for enhanced oil recovery.