The pressure-based acoustic approximation of the elastic wave equations in anisotropic media has advantages corresponding to computational efficiency and numerical stability. However, the numerical scattering potentials from the anisotropic parameter perturbations for the pressure wavefield are not consistent with the elastic scattering theory. In multiparameter full-waveform inversion (FWI), choosing a suitable parameterization, considering the acquisition parameters (e.g., the offset-to-depth ratio and frequency band) and the accuracy of the anisotropy information in the background initial velocity model, is an important component to a successful anisotropic parameter estimation, because the parameterization determines the trade-off between inverted model parameters and their resolution power. However, because it is difficult to perform multiparameter FWI with various types of parameterization using the pressure-based acoustic wave equation, inaccurate scattered wavefields cause the gradient direction to lose its unique properties with respect to each model parameter. To overcome these issues, we adopt the combination of pressure- and vector-based acoustic wave equations converted vector virtual sources, which preserves the computational efficiency and the angular dependency of the partial derivative wavefields in elastic media. With the proposed method, we generate the numerical PP scattering patterns for various parameterizations, which are consistent with the elastic scattering theory. Through the numerical tests using the synthetic anisotropic Marmousi-II models and a real ocean bottom cable dataset from the North Sea, we conduct acoustic FWI with three different parameterizations using the proposed method and verify that the modified scattering patterns accurately reflect the characteristics of the anisotropic parameter perturbations.
|Original language||English (US)|
|Number of pages||11|
|State||Published - 2021|
Bibliographical noteKAUST Repository Item: Exported on 2021-09-09
Acknowledgements: This work was supported by the Basic Research Project of the Korea Institute of Geoscience and Mineral Resources (GP2020-007) funded by the Ministry of Science and ICT, by the National Foundation of Korea (NRF) funded by the Ministry of Science and ICT (NRF-2019K1A3A1A80113341, NRF-2020R111A3073977) and by the Nuclear Safety Research Program through the Korea Foundation Of Nuclear Safety (KoFONS), granted financial resource from the Nuclear Safety and Security Commission (NSSC), Republic of Korea (No.1705010). Also, the North Sea data are released by Equinor and former Volve license Partners under Creative Commons License. We greatly appreciate their efforts to disclose the Volve data. The views on the Volve data expressed in this paper are the views of the authors and do not necessarily reflect the views of Equinor and former Volve license Partners. We would like to thank the editor, an anonymous reviewer, and Prof. Tariq Alkhalifah in King Abdullah University of Science and Technology for their helpful suggestions.
This publication acknowledges KAUST support, but has no KAUST affiliated authors.
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