Optimized Seismic-Guided Low-Carbon Footprint 3D Marine Magnetotelluric Imaging of Complex Fold-Thrust Belt in NW Borneo, Malaysia

3D magnetotelluric (MT) imaging offers potential as a cost-effective, relatively low carbon footprint solution to imaging subsurface for new energy exploration, such as geothermal ( Soyer et al., 2018 ). In this paper, we studied several practical aspects of seismic-guided marine MT inversion to improve them. Firstly, we establish the suitable regularization weights based on a suite of synthetic inversion tests. Secondly, we compare the use of structure tensors derived from anisotropic pre-stack depth migration (APSDM) reflectivity, high-fidelity full-waveform inversion (FWI) velocity and acoustic impedance inversion volumes to guide cross-gradient anisotropic resistivity inversion with initial half-space resistivity starting models. Thirdly, we determine post-facto the optimum structure tensor weights using well logs as the ground truth. We found that utilizing initial model built using horizon-based interpolated resistivity logs from multiple wells and seismic FWI velocity as guide gave the best match to well logs as compared to a model which used standard smoothness constraint only. For new frontier exploration areas with inadequate well control, our study suggests that the structure tensor from APSDM reflectivity data will be the preferred structural guide since the APSDM reflectivity data have well-defined structural information.