Mineral trapping of CO_2 at Nagaoka test site

摘要

Mineral trapping of CO_2 is considered as the most secure mechanism in geological sequestration of CO_2. We collected reservoir rocks and formation water from the pilot-scale CO_2 injection site at Nagaoka city, Niigata Prefecture, Japan. By using the reservoir rocks and formation water, we performed batch experiments to examined major geochemical reactions at Nagaoka test site. Our results showed the reactive surface area of the reservoir rock samples were smaller than that obtained from the BET measurements. We found the geometry surface area is better rather than the surface area estimated from the BET measurements in the geochemical reaction modelling. The precipitation of calcite may dominate the mineral trapping of CO_2 in the long term geochemical reactions. This is also supported by the sampling results of CHDT (Cased Hole Dynamic Tester).