Semi-continuous electrical resistivity tomography monitoring for CO<sub>2</sub> injection at the CaMI Field Research Station, Newell County, Alberta, Canada
Marie Macquet, Don C. Lawton, Dennis Rippe, Cornelia Schmidt‐Hattenberger
Abstract
CMC’s CaMI Field Research hosts a broad range of geophysical and geochemical instruments used to quantify the detection threshold for different monitoring technologies for CO2 injected and stored in the subsurface. In this paper, we show results from the borehole-borehole Electrical Resistivity Tomography (ERT) method. We present the method and the dataset, the time-lapse inversion results, and the future work. The raw data shows a good correlation between resistivity index (ratio between baseline resistivity and monitor resistivity) and the CO2 injection history. The inversion results show two zones with resistivity increase: at 300 m depth (corresponding to the injection zone) and at 280 m depth (corresponding to a coal zone). The CO2 saturation estimated from the inverted resistivity models is in good correlation with the CO2 reservoir modelling. Between the two high-resistivity zones is a zone where the resistivity decreases. A full comprehensive analysis of the system complexity (CO2 injection, dissolution, geochemical processes, CO2 migration) and their impacts on the resistivity are still being addressed to fully understand these results.