Enhanced carbon utilization and storage: An application of nonionic-based binary surfactant CO foam.

Mobility control of CO is important for effective subsurface utilization and sequestration of anthropogenic CO in depleted formations. This not only enhances oil recovery but also increases CO storage efficiency, addressing a key challenge for a future zero-carbon economy. In this study, novel techniques were developed by injecting CO foam generated with a nonionic-based binary surfactant system to improve geological CO storage and to co-optimize carbon utilization and storage efficiency in high salinity carbonate porous media, based on hypotheses from our previous works. Carbonate core samples from a producing oil field were used as the porous media to evaluate oil production and CO storage with varying injectants. The introduction of foam as a mobility control fluid significantly increased the CO retention factor by 4.6 times. With the addition of a nonionic-based binary surfactant system as a foaming agent, the retention factor further increased to 5.6 times. This is in addition to an 85% increase in oil recovery. This study demonstrates the potential of surfactant foams to control the mobility of injected gas, thereby enhancing CO retention in carbonate porous media. The findings highlight the effectiveness of nonionic-based binary surfactant systems as foaming agents for the co-optimization of carbon utilization and storage in depleted oil formations.