Assessing the Cost‐Benefit of Multi‐Core Cables and Non‐Polarizable Electrodes on Shallow Time‐Domain IP Surveys

Abstract

It has become a common procedure to acquire electrical data for environmental surveys with multi-core cables and multi-channel readers. These systems use pre-loaded protocols that instruct the relay box to combine the electrodes in hundreds of possible arrangements. When acquiring Induced Potential (IP) data, there is always a fear of electromagnetic (EM) coupling on the cables and polarization effects on the steel electrodes. As a precaution, current cables are usually separated from the potential cables and non-polarizable electrodes are used for potential readings. This also implies that special care must be taken when writing the acquisition sequence protocols. All these precautions increase considerably the time needed to assemble and disassemble a line thus leading to greater cost and lesser production. In this work, the effects of multi-core cables and non-polarizable electrodes on shallow time-domain IP surveys are analyzed from a practical point of view. It is shown that, if the instrument is able to perform Self Potential (SP) correction before integration, the results obtained with stainless steel electrodes and multicore cables are virtually the same as those obtained with separate cables and non-polarizable electrodes.

Geoelectrical imaging in the interpretation of geological conditions affecting quarry operations

“…With some electrical resistivity equipment, it is possible to measure IP at the same time as ERI, to complement it. This is particularly useful where noise affects the IP data as the ERI data will almost always be acceptable (Dahlin et al 2002;Leroux and Dahlin 2003;Maia and Castilho 2008). Electrode contact resistance also plays an important role, and generally high resistivity material at the surface is problematic.…”