Enhanced CO2 trapping by hydrophobically modified polymer stabilized foam: Significance for CO2 geo-storage

A well-designed aqueous foam promotes CO2 capillary trapping, facilitating in-situ gas storage. This study utilizes hydrophobically modified polymers (HMPs) to enhance conventional foam properties. Comparative analysis using HMPs and classical polymers highlights the improvement of CO2-foam strength and viscosity. Static foam tests reveal that HMP-stabilized foam could maintain foamability compared to HPAM-stabilized foam. The lower molecular weight HMP even could demonstrate high foam capacity and stability. Rheological behavior and texture visualization under supercritical conditions were assessed to understand the impact of polymer addition on foam apparent viscosity and shear tolerance under insitu conditions. HMP presence doubled the foam viscosity, refining its texture and optimizing the foam properties through hydrophobic interactions and molecular networks. This leads to high-strength foam films effectively restraining CO2 flow. Moreover, HMP-stabilized foam achieved over twofold mobility control in porous media compared to polymer-free foam. The research advocates the extended use of this innovative foam formulation to enhance foam properties and flow behavior, with implications for effective CO2 flow diversion and capillary trapping for improved CO2 placement in subsurface formations.