Exploring Cole-Cole parameters: TDIP data inversion and subsurface characterization

Abstract

The present research investigates the outcomes of inverting time domain induced polarization (TDIP) data, emphasizing the influence of parameters governing the IP response curve. In the subsurface, a resistive network follows relaxation patterns governed by the Cole-Cole model, where parameters like resistivity (ρ), chargeability (m), relaxation time (τ), and frequency exponent (c) shape the IP decay curve. Our exploration commences with exercises in forward modeling to understand how each parameter individually impacts the IP phenomenon. Subsequently, we introduce a tailored 1D forward modeling code dedicated to time domain IP, followed by a non-linear inversion process using the heat bath algorithm. These modeling equations are inherently non-linear, with the Cole-Cole parameters acting as independent variables. Using MATLAB, we implemented and rigorously validated this code using synthetic data and real field data gathered from the Sundarbans delta in West Bengal’s lower deltaic region. To delve deeper into subsurface dynamics, we created contour plots resembling pseudo sections for each Cole-Cole parameter, unveiling their subsurface variations. Notably, our results demonstrate a strong correlation with the geological features of the studied area.