CAUSES OF ABNORMALLY LOW PRESSURE AT BRAVO DOME AND ITS IMPLICATIONS FOR CARBON CAPTURE AND STORAGE (CCS)
Common explanations for abnormally low pressures include erosional unloading (Neuzil and Pollock 1983), regional groundwater circulation through low permeability beds (Senger et al. 1987), and cooling (Barker 1972) cannot explain the observed low pressure. Here we introduce the dissolution of CO2 into the brine as a new process that can reduce gas pressure in a compartmentalized reservoir. This research suggests that erosional unloading, cooling of volcanic CO2, and dissolution of CO2 into brine can only explain 5%±1%, 14%±4%, and 14%±3% of the total pressure drop, respectively. This suggests that CO2 dissolution may contribute significantly to reduce the initial pressure build-up due to injection. Our results also imply that the formation was already significantly below hydrostatic pressure before the CO2 was emplaced and that abnormally low-pressured formations should be primary targets for geological CO2 storage.