An anisotropic waveform inversion using an optimal transport matching filter objective: an application to an offshore field dataset

• Published in: IEEE transactions on geoscience and remote sensing Vol. 61; p. 1
• Main Authors: Sun, Bingbing, Alkhalifah, Tariq
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.01.2023; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Anisotropic magnetoresistance; Anisotropy; Anomalies; Data models; Datasets; Filtering theory; Frequency measurement; full-waveform inversion; Geologic measurements; Gravitational effects; Gravity; Gravity effects; Isotropy; Matched filters; Matching; matching filter; Nonlinear systems; Nonlinearity; Offshore; optimal transport; P-waves; Seismic waves; Transport; Velocity measurement; Waveforms; Wavelength
• ISSN: 0196-2892; 1558-0644
• DOI: 10.1109/TGRS.2023.3271117

Considering the conventional seismic wavelength, and the nature of the Earth layering, seismic waves experience, in many parts of the subsurface, considerable anisotropy, and with the effect of gravity on sedimentation, the anisotropy tends to be of a transversely isotropic with a vertical axis of symmetry (VTI) nature. Inverting for such a model of the Earth using waveforms, we face considerable nonlinearity and parameter trade-off. A recently introduced optimal transport of the matching filter (OTMF) provided us with a robust misfit function for reducing cycle-skipping in Full-Waveform Inversion (FWI). We apply a VTI FWI using the OTMF misfit on a field dataset from offshore Australia, comparing its performance to that of conventional FWI using the L2-norm misfit in a variety of circumstances. Due to strong anisotropy in this region, an isotropic inversion though can fit the record, leading to common image gathers with sizable linear moveouts. Thus, in an anisotropic VTI setup, starting the inversion from 3 Hz, both the L2 norm and the OTMF misfit functions can generate a geologically meaningful model, and recover similar anisotropy anomalies. We demonstrate that the OTMF misfit, in some sense, can address the nonlinearity of FWI due to its intrinsic global updating features. Compared to the results from isotropic full-waveform inversion, the improvements in the RTM image and the common image gathers further demonstrate the benefits of including anisotropy in the FWI inversion engine, as well as, the good performance of the OTMF in mitigating cycle-skipping.