oa First Numerical ERT Models for CO2 Plumes in Saline Reservoir with Diverse Crosshole Configurations

Electrical resistivity tomography ERT survey performance in boreholes BRT is studied by numerical forward and inverse simulations to test its sensitivity to changes induced by CO2 injection and migration. Compared with seismic, BRT has lower resolution, but its permanent installation and continuous time-lapse monitoring make it an economical alternative. ERT applications in CO2 storage in saline aquifers are powerful in quantifying intrinsic property changes with time due to the strong contrast between resistive (supercritical) CO2 and conductive saline water reservoir. The resolution of ERT-time lapses is enhanced by applying a constrained inversion with exact apriori geological/structural information on the subsurface from seismic and log data. Our numerical 2D and 3D modelling reveals the capability of BRT techniques to map CO2 plumes and changes as a function of thickness, concentration and electrode configuration as well as modelling and inversion constraints. Some configurations are more favoured due to their better spatial resolution and lower artefacts.