Date of Acceptance: 17/04/2014 Acknowledgments The authors sincerely thank the Guest Editor Irina Artemieva and the two anonymous reviewers for their useful comments. Funding for this Project has been partially provided by the Spanish Ministry of Industry, Tourism and Trade, through the CIUDEN-CSIC-Inst. Jaume Almera agreement (ALM-09-027: Characterization, Development and Validation of Seismic Techniques applied to CO2 Geological Storage Sites) and by the European Union through the Technology Demonstration Plant of Compostilla OXYCFB300 Project (European Energy Programme for Recovery). Additional support has been provided by Spanish Ministry of Education Science (CSD2006-00041), Generalitat de Catalunya (2009SGR006) and CSIC JAE-Doc postdoctoral research contract (E.S.). The sole responsibility of this publication lies with the authors. The European Union is not responsible for any use that may be made of the information contained herein. Juan Alcalde is being currently supported by the Fundación Ciudad de la Energía (CIUDEN) Research training program. The authors would like to sincerely thank Javier Elío for his kind help with the capacity estimation calculations, Institut Geològic de Catalunya for their useful work with the GWs, GEMODELS/UB and to all the people involved directly or indirectly in the elaboration of this work.