A novel CO₂ foam stabilizer based on natural polysaccharide psyllium seed gum: Experimental and molecular dynamics...

The development of eco-friendly polymer foam stabilizers represents an emerging frontier in sustainable oil recovery, addressing the performance limitations and environmental persistence of traditional foam stabilizers under high-temperature and high-salinity conditions. This study proposes a novel use of natural psyllium seed gum (PG) as a foam stabilizer for CO₂ foam flooding technology. A comparative analysis with polyacrylamide and xanthan gum demonstrates the effectiveness of PG in improving foam performance while elucidating its stabilization mechanism. PG exhibits the highest drainage energy barrier (45.13 kJ/mol) and the lowest ripening rate (8.61 × 10³ μm³/min) at high-temperature (110 °C) and high-salinity (1 × 10⁵ mg/L) conditions, significantly improving the CO₂ foam stability. The stabilization of foam under high-temperature and high-salinity conditions is attributed to the formation of polymer/surfactant complexes between PG and the surfactant through hydrogen bonding, which enhances the elasticity of the interfacial film. Furthermore, the double helix configuration of PG forms an interwoven network structure that boosts the viscoelasticity of the bulk solution and strengthens the foam lamella. This study offers innovative insights and robust support for the application of polymer-reinforced CO₂ foam technology, positioning it as a promising next-generation foam stabilizer.