Regional-scale FWI of wide-angle OBN data from a crude initial model using graph-space optimal transport

PreviousNext No AccessFirst International Meeting for Applied Geoscience & Energy Expanded AbstractsRegional-scale FWI of wide-angle OBN data from a crude initial model using graph-space optimal transportAuthors: Andrzej GórszczykRomain BrossierLudovic MétivierAndrzej GórszczykUniversité Grenoble Alpes, ISTerre, F-38058 Grenoble, France and Polish Academy of Sciences, Institute of Geophysics, Warsaw, Poland.Search for more papers by this author, Romain BrossierUniversité Grenoble Alpes, ISTerre, F-38058 Grenoble, France.Search for more papers by this author, and Ludovic MétivierUniversité Grenoble Alpes, ISTerre, F-38058 Grenoble, France and CNRS, Université Grenoble Alpes, LJK, F-38058 Grenoble, France.Search for more papers by this authorhttps://doi.org/10.1190/segam2021-3577774.1 SectionsSupplemental MaterialAboutPDF/ePub ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinked InRedditEmail AbstractRegional-scale imaging with full-waveform inversion of sparse long-offset ocean-bottom node data is inherently difficult. In particular, the large number of wavelengths that have to propagate within the volumetric model-space makes the inversion prone to cycle-skipping. While building an accurate initial model that predict the synthetic data with half-wavelet accuracy might be problematic due to the sparsity of the ocean-bottom nodes, solutions can be found from full-waveform inversion schemes based on alternative misfit functions. The recently developed graph-space optimal transport misfit function is designed for an improved convexity with respect to shifted patterns in the seismic signals - and therefore to the kinematic errors of the velocity model. In principles, this shall make it possible to successfully invert the data starting from a crude initial model. Here we show how using full-waveform inversion based on this misfit function, combined with multiscale data-selection strategy, we are able to make inversion converge from a simple 1D starting model. Despite the fact that the kinematic inaccuracy between the observed and the synthetic first-arrivals is reaching five cycles in the initial stage, we are able to bring the data in phase and obtain geologically consistent velocity model of the complex subduction zone. The presented approach can therefore significantly relax the constraint on the kinematic accuracy of the initial FWI model which is typically derived by traveltime tomography.Keywords: full-waveform inversion, ocean-bottom node, crustal structurePermalink: https://doi.org/10.1190/segam2021-3577774.1FiguresReferencesRelatedDetails First International Meeting for Applied Geoscience & Energy Expanded AbstractsISSN (print):1052-3812 ISSN (online):1949-4645Copyright: 2021 Pages: 3561 publication data© 2021 Published in electronic format with permission by the Society of Exploration GeophysicistsPublisher:Society of Exploration Geophysicists HistoryPublished: 01 Sep 2021 CITATION INFORMATION Andrzej Górszczyk, Romain Brossier, and Ludovic Métivier, (2021), "Regional-scale FWI of wide-angle OBN data from a crude initial model using graph-space optimal transport," SEG Technical Program Expanded Abstracts : 707-711. https://doi.org/10.1190/segam2021-3577774.1 Plain-Language Summary Keywordsfull-waveform inversionocean-bottom nodecrustal structurePDF DownloadLoading ...