2D time domain inversion of induced polarization data

We have developed a new, robust 2D inversion approach for modelling time domain induced potential data. Instead of considering the integral chargeability, the full IP waveform is modelled allowing inversion for spectral content in terms of the Cole-Cole parameters. The method is based on a finite element complex resistivity forward response, which is transformed to the time domain using a Fast Hankel Transform. The forward response is implemented in a general inversion code where constraints can be applied on all model parameters to allow migration of information along the profile. A priori information from e.g. boreholes may also be included to constrain the inversion.