Tomography-mode full-waveform inversion with structural shaping regularization

Abstract

Full waveform inversion (FWI) is the combination of the tomography mode and the migration mode. It is essential to emphasize tomographic component during the early stage of inversion when the initial model is far away from the true model. To prevent the inverted model from falling into local minima, we develop a method to update tomographic lowwavenumber components under the frame of FWI with structural shaping regularization. We firstly separate the conventional FWI gradient into tomography and migration modes based on an implicit wavefield decomposition method. Then the tomography mode is used to emphasize low-wavenumber component updates, while the migration mode is used to estimate local-dip information. Then we introduce structural shaping regularization using seislet transform to mitigate the artifacts caused by the leakage of migration component in tomographic updates. Numerical results show that tomography-mode FWI with structural shaping regularization (RSFWI) is stable and effective to recover a background velocity model. The final inverted velocity model is more accurate than the conventional FWI result.