This book is about CO2-philic surfactants evaluation for application in foam assisted CO2-WAG injection (FAWAG), under immiscible conditions of a Malaysian reservoir. The conventional foaming surfactants suffer from detrimental effect of oil, need of copious amount of water, adsorption or partitioning between water and oil, and sensitivity to the reservoir conditions. Addition of CO2-philic functionalities in surfactant structure is suggested to enhance foam stability, mobility control, and propagation. However, there is a lack of general guideline on CO2-philic surfactant blending that is complied with surfactant structure, properties and foaming functioning. In this book, the structure-property analyses of CO2-philic surfactants are presented under the reservoir conditions in terms of CO2 dissolution in aqueous phase, effect of surfactant on fluid/fluid/gas interfaces, and foam stability and mobility control in the presence of oil. The surfactant with sufficient CO2-philic functionalities and a high degree of branches in structure proved to be stronger foam, which is supported by high surfactant activity at gas/water interface in terms of dissolution and interfacial tension.