Andrés Pérez Estaun

Passive Seismic Monitoring of an Experimental CO2 Geological Storage Site in Hontomín (Northern Spain)

Carbon dioxide capture and storage (CCS) has been recognized as a promising option for dealing with emissions from fossil fuel combustion to decrease the release of CO2 into the atmosphere. Through the CCS process CO2 is first separated from flue gases, then it is compressed and transported to the storage site, and finally it is injected into deep underground geologic formations (Benson, 2005; CO2 Capture Project, 2009). The geologic formations that offer secure and long‐term potential for the storage of large amounts of CO2 are gas and oil reservoirs that are depleted or nearing depletion, deep saline aquifers, and unminable coal seams or coalbed methane formations (Jean‐Baptiste and Ducroux, 2003). Deep saline formations offer the largest potential storage capacity, according to global storage capacity estimates (Benson, 2005). They are also promising due to their wider regional coverage and potential proximity to CO2 capture sites (CO2 Capture Project, 2009). The number of research and development projects for underground CO2 storage has increased greatly over the past decade, facilitated by the International Energy Agency Greenhouse Gas (IEAGHG) Research and Development (R&D) Program. Information on all known CSS demonstration projects worldwide can be found at the IEAGHG website (http://www.ieaghg.org/, last accessed September 2012). In this context, the Spanish Foundation “Ciudad de la Energia” (CIUDEN) is developing a CO2 Geological Storage Program in saline aquifers in Spain. One of the main objectives of the program, which is now in its pre‐operational stage, is to set up a technological laboratory, to develop technology, and to test methodologies on CO2 storage operation, with the final goal of making the geological storage environmentally safe and technologically viable. The site selection and characterization studies performed on several target geologic formations have identified a suitable experimental and demonstration …