Hydrogeological applications of electrical impedance tomography

Wherever a process generates a sufficient contrast in ground resistivity (Omega), monitoring the Omega structure over time Delta Omega/Delta t) may give insight into these processes. Electrical Impedance Tomography (EIT) has applications in Enhanced Oil Recovery (EOR). Slurry Fracture injection (SFI), and hydrogcological transport process monitoring. Surface-obtained EIT image resolution is usually poor. Given the same excitation current and ground factors, there are three approaches to improving image resolution: i.) Increasing measuring instrument accuracy and precision, ii.) Optimizing electrode arrangements with respect to the Omega anomaly, and, iii.) Processing data with methods that eliminate noise and improve the Q-distribution map resolution. We examined these approaches for a field experiment near Cambridge, Ontario. Results show that EIT can be used to monitor such processes, but improvements in commercially available instruments are badly needed.