THE ROLE OF NOBLE GASES IN FUTURE STRATEGIES FOR MONITORING CARBON CAPTURE AND STORAGE (CCS) WITH EXAMPLES OF APPLICATIONS TO GEOLOGICAL RESERVOIRS IN THE DEEP SOUTH

Sedimentary strata in various settings offer potential for injection and storage of captured CO₂ and the options for land-based storage offer certain advantages in cost of injection and versatility in access, management and monitoring of injected CO₂. CO₂ becomes a supercritical fluid at crustal depths > 800 meters, where it can be stored beneath relatively impermeable strata in naturally occurring deep crustal fluids (commonly brines), preferably within reservoirs offering relatively simple stratigraphic context. Geological reservoirs in Alabama, Mississippi, Georgia, South Carolina and northern Florida have the capacity to store injected CO₂ at a scale of hundreds of gigatons (Gt). Noble gases can be utilized to ‘fingerprint’ CO₂ captured from various sources and monitor the distribution and ultimate fate if injected CO₂. Atmospheric, crustal, and mantle reservoirs for Earth’s fluids have distinctive compositions of naturally occurring He, Ne, Ar, Kr and Xe isotopes, and can be used in combination with measurements of traditional stable isotopes and isotopologues of the light hydrocarbons to derive monitoring strategies appropriate to the geological storage. Characterization of the naturally occurring deep crustal microbiome can also be conducted in combination with isotopic studies. It is ideal for such characterizations to be made in a purely scientific context to study the natural system, prior to the application of CO₂ injection at scale, so that changes to isotopic systems and the endemic populations of bacteria and archaea can be tracked following CO₂ injection. The Auburn Noble Isotope Mass Analysis Lab (ANIMAL) includes three MAP-215 noble gas mass spectrometers suitable for analysis of the entire suite of noble gases that can be configured with extraction lines for analysis of fluid samples. With new funding from the American Chemical Society, we seek to help create opportunities for student-driven research with a broad range of collaborators in the isotopic and biologic systems of deep crustal fluids in anticipation of CO₂ storage at scale in our region. This presentation will highlight the potential for CCS in the Deep South in settings including the Tuscaloosa and Eutaw Formations of southern Alabama and Mississippi and strata beneath Mesozoic basalts of the South Georgia rift basin.