Forward modelling and inversion of self-potential anomalies caused by 2D inclined sheets

Abstract

Self-potential anomalies observed over sulfide ore bodies can be closely associated with electrochemical reactions and the ohmic potential drop within the rocks. Self-potential surveys based on laboratory measurements of electrochemical potentials allow us either to measure the amplitude of the anomalies generated by this mechanism or to determine the model parameters. In order to achieve these goals, two sheets of zinc and copper were joined together to simulate sheet-like ore bodies. Self-potential surveys were conducted over 684 electrodes with the purpose of revealing the influence of various angles of the sheet. In a laboratory experiment, four different inclinations were chosen to perform the forward modelling. The last part of this paper involves the inversion of measured data to recover the distribution of generated self-potential signals. The inversion results show a satisfactory agreement with the laboratory measured data. Finding the geometry of the buried source from the shape of the SP response is not intended as it is fixed in advance. The first aim of this paper is to show how the SP response is affected under the presence of a 2D conductive structure (sheet-like) in tank experiments. The second aim is to obtain one of the model parameters (coefficient M) using data regression.