Mineral carbon storage in mafic and ultramafic rock masses has the potential to be an effective and permanent mechanism to reduce anthropogenic CO₂. Several successful pilot‐scale projects have been carried out in basaltic rock (e.g., CarbFix, Wallula), demonstrating the potential for rapid CO₂ sequestration. However, these tests have been limited to the injection of small quantities of CO₂. Thus, the longevity and feasibility of long‐term, large‐scale mineralization operations to store the levels of CO₂ needed to address the present climate crisis is unknown. Moreover, CO₂ mineralization in ultramafic rocks, which tend to be more reactive but less permeable, has not yet been quantified. In these systems, fractures are expected to play a crucial role in the flow and reaction of CO₂ within the rock mass and will influence the CO₂ storage potential of the system. Therefore, consideration of fractures is imperative to the prediction of CO₂ mineralization at a specific storage site. In this review, we highlight key takeaways, successes, and shortcomings of CO₂ mineralization pilot tests that have been completed and are currently underway. Laboratory experiments, directed toward understanding the complex geochemical and geomechanical reactions that occur during CO₂ mineralization in fractures, are also discussed. Experimental studies and their applicability to field sites are limited in time and scale. Many modeling techniques can be applied to bridge these limitations. We highlight current modeling advances and their potential applications for predicting CO₂ mineralization in mafic and ultramafic rocks.

Micromodels have been widely used to visualize surfactant flooding, which provides new insights into understanding pore-scale events during displacement. In this review, recent advances in micromodel studies of surfactant flooding are briefly summarized. The mechanisms of surfactant flooding as demonstrated by micromodel studies are presented, as well as pore-scale findings that cannot be captured by traditional coreflood methods.

Drainage displacement at unfavorable viscosity ratios is often encountered in oil recovery, CO₂ sequestration, and NAPL remediation, which significantly limits recovery of fluids from porous media. Surfactants have been extensively used as wettability modifiers to improve hydrocarbon recovery from rock matrix by imbibition. But little attention has been paid to the effect of surfactant‐assisted wettability alteration on displacement in non‐fractured porous media. In this study, we investigate surfactant‐assisted immiscible displacement in NAPL‐wet microfluidic chips. We find that the change of advancing contact angle by surfactant is velocity dependent. A stable displacement can be achieved at low velocity when wettability‐altering surfactant solution is used as injection fluid. In comparison, fingering occurs at all capillary numbers for water injection, resulting in low NAPL recovery. The generation of NAPL ganglion during waterflooding is significantly different from that during wettability‐altering surfactant flooding. The generation of NAPL ganglion during wettability‐altering surfactant flooding is related to velocity and saturation due to the wettability alteration and interfacial tension reduction. In contrast, the production of NAPL ganglion during waterflooding is only saturation dependent. NAPL ganglia generated during wettability‐altering surfactant flooding are primarily within the pore‐size range and can be easily recovered in subsequent recovery processes. To the best of our knowledge, this study reveals for the first time the pore‐scale mechanism of surfactant‐assisted wettability on the immiscible displacement, which is important for highly efficient NAPL remediation.