Cross-Hole ERT Measurements in Slotted PVC Cased Boreholes - A New Perspective in Geoelectrical Prospection

In this work we study the case of performing cross-hole ERT measurements in plastic PVC cased slotted observation boreholes by inserting a multi-electrode cable directly into the borehole. We present results from an experimental study by setting up simulations in a water tank using different PVC casings, with various number of slots and by testing them using different electrode array configurations.

The findings of the experimental test were also tested by field data. We conclude that the applicability of this measurement set-up depends on the density of the slots on the PVC casing, with denser slot configurations leading to a better data quality. Among the tested configurations, the pole-dipole array is shown to be the most preferable array. The previous findings are verified by the field data results, giving a new perspective for geoelectrical prospecting, since the obtained results suggest that slotted PVC cased observation wells can be efficiently employed for ERT mapping, reducing the overall survey costs, reliability and effort, especially in urban environments.