Magnetotelluric surveys (soundings) are a naturalsource electromagnetic (EM) geophysical method that utilizes variations in the Earth’s magnetic field to image subsurface structures. A magnetotelluric sounding was attempted at Weyburn but has not produced results. Consequently, a final assessment of its utility is not available (Monea et al., 2008). Electrical resistance tomography (ERT) is a technique of imaging subsurface electrical conductivity. When deployed in time-lapse mode, it is capable of detecting conductivity changes caused by the injection of CO2. The method utilizes borehole casings as electrodes for both stimulating electrical current in the ground and measuring the electrical potentials that are induced. ERT may be tested in Weyburn Phase II using a single borehole configuration as an.
