Applicability of long-range seismic noise correlation for CO2 geological storage monitoring

As correlation of broadband seismic noise begins to be used for long-term monitoring of geological objects, we assess the theoretical feasibility to monitor CO2 geological storage with this method. We use the Ketzin pilot project speed profile in order to compute the theoretical speed perturbation of Rayleigh waves, and we compare them to natural variations recorded on the field using a broadband network. Our results show that, if we consider a theoretical demonstrator-scale injection at the Ketzin site, the perturbation induced by the CO2 bubble is greater than recorded natural variations. We show that the method is sensible to CO2 bubble cross-sections: a 3D tomography is therefore possible with a carefully placed network. For a CO2 geological storage geology similar to Ketzin, the minimum cross-section that can be detected is 100 000 m(2), 500 meters wide if the whole 200m reservoir level is filled. (C) 2013 The Authors. Published by Elsevier Ltd.