How will reservoir and caprock react with injected CO{sub 2} at Sleipner? Preliminary evidence from experimental investigations

Geochemical investigations are being undertaken, as part of the Saline Aquifer CO{sub 2} Storage (SACS) project, to determine the potential for chemical reactions between injected CO{sub 2} formation water and the reservoir rock (Utsira sand) or caprock (Nordland Shale). Closed-system batch experiments and open-system core-flood experiments are being conducted under reservoir conditions for timescales up to 24 months. Preliminary analysis of (up to 3-month) experiments indicate very little change in Utsira sand composition and that the synthetic porewater used in the experiments is close to chemical equilibrium with the Utsira sand. The presence of CO{sub 2} initiated limited carbonate dissolution, due to a decrease in pH. These experiments are ongoing with some having over 12 months left to run. The results from the experiments will be interpreted using standard geochemical codes, and chemical simulators developed for the SACS project. 5 figs., 1 tab.