Forward and inverse Cole?Cole modelling in the analysis of frequency domain electrical impedance data

Abstract

An interactive computer program to model frequency domain complex resistivity data has been developed using the Cole?Cole model. This simple, well established model, based on the mathematical response of an electrical circuit, is effective in modelling the electrical impedance of a mineralized rock, particularly sulphide mineralization. Model parameters: Resistivity R; chargeability, m; frequency dependence, c; and time constant r, are estimated by forward modelling. An inversion technique, ridge regression, is used to obtain the parameters corresponding to the "best fit" curve. The program, written in Turbo Basic, is designed to run on any IBM PC/XT/AT or close compatible. It incorporates a well structured approach with ease of operation, employing simple to use menus and descriptive error messages. Input is via the keyboard or through a file system. Output is tabular and graphical, showing the measured and predicted data, and a least squares error estimate.