Influence of electrode polarization on the potential of DC electrical exploration

Abstract

The accuracy of data obtained with the Direct Current (DC) electrical method is reduced by the electrode polarization effect, which is caused by current stimulation when the electrodes of the multi-electrode acquisition system are alternately used as the current and the potential electrodes. With the purpose of studying the characteristics of electrode polarization, the continuous potential responses of the electrodes in a conventional multi-electrode acquisition system (single-mode multi-electrode acquisition system) and the proposed double-mode multi-electrode acquisition system were adopted before and after current stimulation, by varying the electrode material, voltage amplitude and current duration. The results showed that for the single-mode acquisition system the electrode polarization was stronger and the electrodes possessed a stronger chemical activity, a longer current duration and a higher voltage amplitude that increased rapidly and then decayed after current stimulation. The average time for the potential to be restored to the background level was greater than 1.5h, and the electrode polarization of a stainless steel electrode was found to be stronger than a copper one. Thus, along with the action of current stimulation, the potential data was significantly influenced by the electrode polarization when adopting a conventional multi-electrode acquisition system. The results also demonstrated that the electrode polarization had a relatively weak influence on the resistivity data due to the data reprocessing.