In this study, the resolution capabilities of electrical resistivity tomography (ERT) in the monitoring of CO 2 injection are investigated. The pole-pole and bipole-bipole electrode configuration types are used between two uncased boreholes straddling the CO 2 plume. Forward responses for an initial pre-injection model and three models for subsequent stages of CO 2 injection are calculated for the two different electrode configuration types, noise is added and the theoretical data are inverted

more »

... ith both L1-and L2-norm optimisation. The results show that CO 2 volumes over a certain threshold can be detected with confidence. The L1-norm proved superior to the L2-norm in most instances. Normalisation of the inverted models with the pre-injection inverse model gives good images of the regions of changing resistivity, and an integrated measure of the total change in resistivity proves to be a valid measure of the total injected volume.