Using an aquifer as CO2 buffer storage

We investigate the prospect of using an offshore aquifer for both CO2 sequestration and as buffer storage for CO2-based enhanced oil recovery (EOR), to reduce the cost of storage and increase flexibility and availability of the CO2. We review the state changes in the well, water content in back-produced CO2, pressure and temperature development of CO2 in well and reservoir, for both injection and back-production. We find that although there is a small window for back-production, it places a high demand on operational stringency and will only deliver a small portion of the total CO2 injected. Our conclusion is that such a project is only theoretically possible and is not recommended.