Measuring and modeling of Ostwald Ripening in Residually Trapped CO2
Dr. Charlotte GaringResearch AssociateStanford Center for Carbon StorageDepartment of Energy Resources EngineeringDespite its major influence on storage capacity, CO2 plume migration rate, and rates of CO2 dissolution and mineralization, residual trapping remains perhaps the least understood of the trapping mechanisms following CO2 injection in geologic formations. Whereas conventional multi-phase flow models assume that the residually trapped non-wetting phase is permanently immobilized, multiple physiochemical mechanisms exist which could potentially invalidate this assumption. One mechanism is CO2 transfer driven by differences in capillary pressure between disconnected neighbor ganglia, called Ostwald Ripening.
This present works investigates i) the potential for Ostwald ripening to remobilize trapped CO2 using synchrotron X-ray microtomography (micro-CT) measurement of trapped gas ganglia capillary pressure and pore-scale modeling of Ostwald ripening mechanism, and ii) the stability of residually trapped scCO2 during the early stages following imbibition CO2 in a sandstone by conducting a drainage-imbibition experiment with reservoir conditions and time-resolved micro-CT imaging.