Geologically Constrained Full-Waveform Inversion Using an Anisotropic Diffusion Based Regularization Scheme : Application to a 3D Offshore Brazil Dataset

Full-waveform inversion (FWI) has now become a standard part of the workflow for building earth-models in the industry given its ability to provide high-resolution high-fidelity earth-models especially in complex geological settings. Inverse problems like FWI are ill-posed and ill-conditioned, which means that their solution is not unique and unstable. Some kind of regularization, usually in the form of smoothing of the model updates, is essential to obtain a stable solution. The most common approaches used in FWI previously, have been ad hoc in the sense that the smoothing parameters have not been influenced by the geology of the subsurface, which results in smoothing across major geological interfaces, such as, between salt and sediment. Here we present a method to regularize the FWI problem using an anisotropic diffusion-based regularization scheme to conform the earth model updates along geological structure automatically derived from a seismic image. We apply this method on a 3D offshore Brazil field dataset and show that it leads to a more geologically plausible model.