Electrical Resistivity Imaging

An extension of resistivity measurements in both the laboratory and field situations is demonstrated. Using high density computer-controlled measurements images of the electrical resistivity distribution in a core, or over an area of ground are produced. At both scales the variability in electrical properties over relatively small distances is evident. In a sediment-core the electrical image shows high resolution detail which complements a conventional photo, thus enhancing the usual interpretation. The electrical resistivity imaging is then used to monitor the passage of a saline intrusion through a volume of rock. Firstly this is demonstrated for a large volume of ground, and then separately for a core sample, This technique can be used to zone areas of investigation, assigning different characteristics to each zone, or to monitor the movement of fluids with time. Its application to both core and site investigations includes hydrocarbon and geotechnical characterisation, as well as aquifer and pollution monitoring.