Author:
Yang Jidong,Xu Jie,Huang Jianping,Yu Youcai,Sun Jiaxing
Abstract
Multi-scale strategies such as starting from the low-frequency and early-arrival part of recorded data are commonly used in full waveform inversion (FWI) to maneuver complex nonlinearity. An alternative way is to apply appropriate filtering and conditioning to the misfit gradient in the model domain. In acoustic constant-density media, we prove that velocity and impedance sensitivity kernels are equivalent to applying a high-pass and a low-pass scattering-angle filter to a conventional single-parameter velocity (CSV) kernel. The high-pass scattering-angle filter allows the velocity kernel to include low-wavenumber updates (tomography component). In contrast, the low-pass scattering-angle filter helps the impedance kernel to yield high-wavenumber updates (migration component). The velocity model can be updated using a hybrid gradient of two components combined with appropriate weights. This FWI scheme is able to overcome the potential nonlinearity and partially mitigate the cycle-skipping problem. Numerical examples for the SEG/EAGE overthrust model and the Marmousi model demonstrate that the hybrid gradient facilitates FWI to converge faster to the true model even in cases when conventional CSV-based FWI fails.
Subject
General Earth and Planetary Sciences
Reference59 articles.
1. Gradient orthogonalization in adjoint scattering-series inversion;Albertin,2013
2. Full-model wavenumber inversion: An emphasis on the appropriate wavenumber continuation;Alkhalifah;Geophysics,2016
3. Scattering-angle based filtering of the waveform inversion gradients;Alkhalifah;Geophys. J. Int.,2015
4. Tomographic full waveform inversion (TFWI) by successive linearizations and scale separations;Almomin,2013
5. Applications of multiscale waveform inversion to marine data using a flooding technique and dynamic early-arrival windows;Boonyasiriwat;Geophysics,2010