Noise strikes, but signal wins in full waveform inversion

Huang, Yi; Mao, Jian; Xing, Hao; Chiang, Chris

doi:10.1190/segam2020-3427856.1

Cited by 6 publications

(1 citation statement)

References 5 publications

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“…ULF Ambient OBN Seismology 7 After analyzing the ambient data and identifying ambient wavefield characteristics that suggested subsurface influence, we were provided with a P-wave velocity (V P ) model by TGS. This FWI model was derived from the higher-frequency active-source P-component data using acoustic FWI (Huang et al 2020). TGS personnel subsequently downsampled the high-resolution model to a uniform 0.1 km spacing in all three dimensions.…”

Section: Amendment Obn Data Setmentioning

confidence: 99%

Observations from the Seafloor: Ultra-low-frequency Ambient Ocean-Bottom Nodal Seismology at the Amendment Field

Girard,

Shragge,

Danilochkine

et al. 2024

Preprint

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Large-scale ocean-bottom node (OBN) arrays of 1000s of multi-component instruments deployed over 1000s of square kilometers have been used successfully for active-source seismic exploration activities including full waveform inversion (FWI) at exploration frequencies above about 2.0 Hz. The analysis of concurrently recorded lower-frequency ambient wavefield data, though, is only just beginning. A key long-term objective of such ambient wavefield analyses is to exploit the sensitivity of sub-2.0 Hz energy to build long-wavelength initial elastic models, thus facilitating FWI applications. However, doing so requires a more detailed understanding of ambient wavefield information recorded on the seafloor, the types, frequency structure and effective source distribution of recorded surface-wave modes, the near-seafloor elastic model structure, and the sensitivity of recorded wave modes to subsurface model structure. To this end, we present a wavefield analysis of low- and ultra-low-frequency ambient data (defined as <1.0 Hz and <0.1 Hz, respectively) acquired on 2712 OBN stations in the Amendment Phase 1 survey covering 2750 km^2 of the Gulf of Mexico. After applying prestack ambient data preprocessing and seismic cross-coherence interferometry workflows, we demonstrate that the resulting virtual shot gather (VSG) volumes contain evidence for surface-wave and guided P-wave mode propagation between the 0.01-1.0 Hz that remains coherent to distances of at least 80 km. Evidence for surface-wave scattering from near-surface salt-body structure between 0.35-0.85 Hz is also present in a wide spatial distribution of VSG data. Finally, the interferometric VSG volumes clearly show waveform repetition at 20 s intervals in sub-0.3 Hz surface-wave arrivals, a periodicity consistent with the mean active-source shot interval. This suggests that the dominant contribution of surface-wave energy acquired in this VSG frequency band is likely predominantly related to air-gun excitation rather than by naturally occurring energy sources. Overall, these observations may have important consequences for the early stages of initial model building for elastic FWI analysis.

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Section: Amendment Obn Data Setmentioning

confidence: 99%

Observations from the Seafloor: Ultra-low-frequency Ambient Ocean-Bottom Nodal Seismology at the Amendment Field

Girard,

Shragge,

Danilochkine

et al. 2024

Preprint

View full text Add to dashboard Cite

show abstract

Full-waveform Inversion Based on q-Laplace Distribution

Silva

Araújo

Corso

2021

Pure Appl. Geophys.

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Observations from the seafloor: ultra-low-frequency ambient ocean-bottom nodal seismology at the Amendment field

Girard,

Shragge,

Danilouchkine

et al. 2024

Geophysical Journal International

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Summary Large-scale ocean-bottom node (OBN) arrays of 1000s of multi-component instruments deployed over 1000s of square kilometers have been used successfully for active-source seismic exploration activities including full waveform inversion (FWI) at exploration frequencies above about 2.0 Hz. The analysis of concurrently recorded lower-frequency ambient wavefield data, though, is only just beginning. A key long-term objective of such ambient wavefield analyses is to exploit the sensitivity of sub-2.0 Hz energy to build long-wavelength initial elastic models, thus facilitating FWI applications. However, doing so requires a more detailed understanding of ambient wavefield information recorded on the seafloor, the types, frequency structure and effective source distribution of recorded surface-wave modes, the near-seafloor elastic model structure, and the sensitivity of recorded wave modes to subsurface model structure. To this end, we present a wavefield analysis of low- and ultra-low-frequency ambient data (defined as <1.0 Hz and <0.1 Hz, respectively) acquired on 2712 OBN stations in the Amendment Phase 1 survey covering 2750 km2 of the Gulf of Mexico. After applying ambient data conditioning prior to cross-correlation and seismic cross-coherence interferometry workflows, we demonstrate that the resulting virtual shot gather (VSG) volumes contain evidence for surface-wave and guided P-wave mode propagation between the 0.01-1.0 Hz that remains coherent to distances of at least 80 km. Evidence for surface-wave scattering from near-surface salt-body structure between 0.35-0.85 Hz is also present in a wide spatial distribution of VSG data. Finally, the interferometric VSG volumes clearly show waveform repetition at 20 s intervals in sub-0.3 Hz surface-wave arrivals, a periodicity consistent with the mean active-source shot interval. This suggests that the dominant contribution of surface-wave energy acquired in this VSG frequency band is likely predominantly related to air-gun excitation rather than by naturally occurring energy sources. Overall, these observations may have important consequences for the early stages of initial model building for elastic FWI analysis.

show abstract

Noise strikes, but signal wins in full waveform inversion

Cited by 6 publications

References 5 publications

Observations from the Seafloor: Ultra-low-frequency Ambient Ocean-Bottom Nodal Seismology at the Amendment Field

Observations from the Seafloor: Ultra-low-frequency Ambient Ocean-Bottom Nodal Seismology at the Amendment Field

Full-waveform Inversion Based on q-Laplace Distribution

Observations from the seafloor: ultra-low-frequency ambient ocean-bottom nodal seismology at the Amendment field

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