CO2 migration monitoring by means of electrical resistivity tomography (ERT)-Review on five years of operation of a permanent ERT system at the Ketzin pilot site

摘要

At the Ketzin pilot site, Germany, electrical resistivity tomography (ERT) is a substantial component in a multi-disciplinary monitoring concept established in order to image CO2 injected in a saline aquifer. Since more than five years, crosshole ERT data sets have repeatedly been collected using a borehole electrode array acting as a permanent reservoir monitoring tool. This contribution summarizes the aspects being essential for a successful deployment and operation of such a downhole installation. It is shown that the presented installation can facilitate stable and reliable data collection at least throughout the investigated five-year period of ongoing CO2 injection. Based on the experiences being gained so far, it is concluded that a properly calibrated and integrated downhole ERT system allows for mapping of quantitative CO2 saturation estimates in the subsurface.