Robust Low-Field NMR for CO₂ Geo-Sequestration: Advances, Challenges, and Perspectives

Low-field nuclear magnetic resonance (LF-NMR) has emerged as a robust, nondestructive diagnostic tool for advancing CO2 geo-sequestration in hydrocarbon reservoirs. This review synthesizes recent progress in its application to characterizing key reservoir and caprock properties, including pore structure heterogeneity, pore size distributions, and wettability dynamics. LF-NMR enables quantitative evaluation of petrophysical parameters essential for storage integrity, injectivity, and long-term containment. Customized systems further allow real-time monitoring of multiphase fluid interactions during CO2 injection, with applications ranging from tracking CH4–CO2 competitive displacement to elucidating pore-scale oil mobilization during miscible and immiscible flooding. These insights highlight how CO2 exposure alters fluid accessibility and interfacial interactions, directly influencing trapping efficiency and hydrocarbon recovery. Nonetheless, LF-NMR faces limitations, particularly in resolving nanopore systems and the absence of standardized testing protocols. Future directions include integrating artificial intelligence to interpret complex multidimensional data and developing universal experimental frameworks. Addressing these challenges will help translate LF-NMR from laboratory research to field-scale deployment, enhancing predictive capabilities for climate-safe carbon management.