Our work in carbon dioxide enhanced oil recovery and reactive flow transport provides a natural connection to the all-important area of CO2 sequestration. Our emphasis has been on reactivity of brine, rock and CO2, and on the integrity of storage in fractured and faulted systems, where the possibilities of fault and seal breaches create significant potential liabilities when considering large-scale CO2 injections in deep, saline aquifers. Some of the important considerations are changes in pore structure as reactions take place. Some of our early work (low-pressure) is focused on imaging the pore space and understanding multiphase fluid distribution.