Lawrence Berkeley National Laboratory

If carbon dioxide capture and storage (CCS) technologies are implemented on a large scale, the amounts of CO2 injected and sequestered underground could be extremely large. The stored CO2 then replaces large volumes of native brine, which can cause considerable pressure perturbation and brine migration in the deep saline formations. If hydraulically communicating, either directly via updipping formations or through interlayer pathways such as faults or imperfect seals, these perturbations may impact shallow groundwater or even surface water resources used for domestic or commercial water supply. Possible environmental concerns include changes in pressure and water table, changes in discharge and recharge zones, as well as changes in water quality. In compartmentalized formations, issues related to large-scale pressure buildup and brine displacement may also cause storage capacity problems, because significant pressure buildup can be produced. To address these issues, a three-year research project was initiated in October 2006, the first part of which is summarized in this annual report.