A field experimental study of CO2 sequestration into the Ogachi hot dry rock (approximately 200 grad C, mainly consists of granitic rocks) have been conducted to explore safe and permanent CO2 storage by creating carbonate minerals in the subsurface. In the CO2-Injection Experiment by single well testing, CO2 dissolved water with a tracer was injected by free flowing injection through a deep geothermal well (OGC-2) to the reservoir. And chemical monitoring with a wireline sampler in batch has been enforced for the estimation of the release of base cations from reservoir rock, reaction of CO2 with cations. Resultant CO2-Tracer balance suggests that carbonates might precipitate in a few days. In addition, the crystal-growth testing in the borehole using a newly developed chemical reactor sonde was implemented to ascertain CO2 fixation as carbonates under in-situ conditions and it was indicated that a spiral growth rate of calcite was order of mm/year. Laboratory experiments and simulations for CO2-water-rock interaction also have been executed to make long-term evaluation of the CO2 storage process and optimization of reservoir modeling. © 2009 Elsevier Ltd. All rights reserved.
Wakahama, H., Mitoa, S., Ohsumi, T., Ueda, A., Yajima, T., Satoh, H., … Kubota, K. (2009). A concept of CO2 Georeactor sequestration at the Ogachi HDR site, NE Japan. In Energy Procedia (Vol. 1, pp. 3683–3689). https://doi.org/10.1016/j.egypro.2009.02.166