CO₂‐Switchable Foams for Enhanced Oil Recovery and Carbon Sequestration

Carbon dioxide (CO₂) foams have emerged as a promising strategy for enhanced oil recovery (EOR), providing effective gas mobility control. However, challenges in maintaining subsurface stability and enabling surface-controlled collapse persist, and a comprehensive assessment of their CO₂ storage potential remains unexplored. This study presents an innovative approach using switchable foams stabilized by a CO₂-responsive surfactant, N-erucamidopropyl-N,N-dimethylamine (UC₂₂AMPM). Through integrated laboratory experiments under simulated reservoir conditions, the reversible foaming/defoaming, in situ foam generation and transport in porous media, as well as CO₂ storage capacity were systematically evaluated. The results reveal a unique reversible foam modulation mechanism driven by alternating CO₂ and N₂ exposure with CO₂-induced foams displaying distinct pressure-dependent stability profiles. Microfluidic visualization technique demonstrates efficient in situ foam generation within porous media, further corroborated by core-flooding experiments revealing resistance factors of up to 14, underscoring their robust conformance control capability. Absorption experiments operating under simulated oil reservoir indicates a 22% increase in CO₂ sequestration efficiency compared to traditional brine flooding. These findings provide a quantitative framework for harnessing the potential of CO₂-responsive foams in both EOR operations and sustainable carbon sequestration.