Surfactant Selection for Foam Generation: Implications for CO2 Geo-Sequestration

The storage of CO2 foam in saline aquifers is an effective way of CO2 geo-sequestration. However, one of the primary concerns during storage of CO2 in underground geological reservoirs is the rapid upward migration of CO2 plume which eventually challenges the containment security. Injection of foam has been proposed as an effective solution to this problem from decades. Foams have low mobility and prevent the formation of high mobility channels. Surfactant is a crucial component in generating stable aqueous foam. The selection of surfactants as foaming agents is very important for the performance of the foam. The stability of a surfactant generated foam depends on the surfactant type, its concentration, salinity, pressure and temperature. In this study, stability of foam generated with two surfactants sodium dodecylbenzenesulphonate (anionic) and cetyl trimethylammonium bromide (cationic) are investigated at different surfactant concentrations. The effect of salinity and temperature were also investigated. The form was generated by purging air into a brine solution containing the surfactant. The foamability and the stability of the produced foam is first observed under room temperature and are then observed under elevated temperatures. The elevated temperature foam stability is observed by keeping the produced foam in an oven. The foamability was observed to increase with surfactant concentration. The salt inhibits generation of foam and the effect is prominent for CTAB than SDBS. The CTAB assisted foam has a higher stability than SDBS. However, at high temperature the foam stability was found to reduce significantly for both SDBS and CTAB; with CTAB foam has slightly higher stability than SDBS.