Anisotropic multimode joint Rayleigh- and Love-wave inversion

Gofer, Edan; Leaney, Scott; Dash, Ranjan K.; Malcotti, Hermes; DiSiena, James

doi:10.1190/segam2021-3590447.1

Cited by 3 publications

References 14 publications

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Joint wave-equation inversion of Rayleigh and Love dispersion curves

Li,

Zhang,

Hanafy

et al. 2024

GEOPHYSICS

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Wave equation dispersion (WD) inversion techniques for surface waves have proven to be a robust way to invert for the shear-wave (S-wave) velocity model. Unlike 1D dispersion curve inversion, the proposed WD method obviates the need for a layered model assumption and reduces the susceptibility to cycle-skipping issues in surface wave full waveform inversion (FWI). Previous WD inversion experiments conducted on Rayleigh and Love waves have highlighted that inverting Love waves yields better stability due to their independence from the P-wave velocity model. Nevertheless, Rayleigh waves possess the advantage of greater penetration depth compared to Love waves with similar wavelengths. Therefore, combining the two types of surface waves is a feasible way to improve the accuracy of S-velocity tomograms. In light of this, we propose a novel approach: a joint WD inversion encompassing both Rayleigh and Love waves. This innovative technique adjusts the weighting of individual WD gradients using the sensitivity factor of an equivalent layered model, offering a significant advancement in subsurface characterization. Synthetic model tests demonstrate that the joint WD inversion method can generate a more accurate S-velocity model, particularly in the presence of complex low-velocity layers (LVL) or high-velocity layers (HVL), when compared to individual wave WD inversion techniques. Simultaneously, the results of field tests validate the effectiveness of the proposed joint WD inversion strategy in producing a more dependable S-wave velocity distribution that aligns closely with the actual geological structure.

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Joint wave-equation inversion of Rayleigh and Love dispersion curves

Li,

Zhang,

Hanafy

et al. 2024

GEOPHYSICS

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Shear-wave value for seismic imaging: Lupin 9C Seismic 3D Survey, Midland Basin, West Texas

Malcotti

Dash

Davenport

et al. 2022

Second International Meeting for Applied Geoscience &Amp; Energy

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Imaging faults and fractures with the difference of fast and slow shear-wave splitting reflectivity, Δγ^(S): 3D/9C survey in Midland Basin, West Texas, and 3D/3C survey in Washakie Basin, Wyoming

Gaiser,

Malcotti,

Dash

et al. 2024

The Leading Edge

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One of the most important applications of shear-wave (S-wave) seismic exploration has been in reservoir fracture characterization. While many advancements have been made over the past 30 years to compute and correct for the long-wavelength kinematics of S-wave splitting (SWS) (fast S-wave polarization directions and slow S-wave time delays), practically no progress has been made in imaging the short-wavelength reflectivity of fractures directly with Δγ(S). This property is the contrast in the SWS anisotropy parameter, γ(S), and represents the reflection amplitude at vertical incidence for changes in fracture density and orientation across an interface. In this article, we examine the Lupin nine-component survey in Midland Basin, Texas, for the technical reliability of imaging fractures in depth with converted P to S waves (PS waves) guided by pure-mode horizontal shear waves and vertical shear waves. Final Δγ(S) amplitude maps for each mode show sensitivity to fractures, faults, and the maximum horizontal stress direction. These maps are computed from the difference between fast and slow S-wave stacks (after SWS analysis and correction) and P-wave amplitude variation with offset gradient stacks. The S-wave difference maps identify an east–west lineament, possibly a strike-slip fault or fracture corridor, that is not observed by P-wave depth slices. Pure-mode S waves and PS waves are orders of magnitude more sensitive to Δγ(S) than P waves. We also review the development of Δγ(S) and find that it has been relatively unexploited by the exploration industry. In addition, we demonstrate that Δγ(S) can be obtained directly from the objective function of the transverse energy to correct for SWS, and show a four-component Alford rotation example from a previous PS-wave survey in the Washakie Basin, Wyoming.

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Anisotropic multimode joint Rayleigh- and Love-wave inversion

Cited by 3 publications

References 14 publications

Joint wave-equation inversion of Rayleigh and Love dispersion curves

Joint wave-equation inversion of Rayleigh and Love dispersion curves

Shear-wave value for seismic imaging: Lupin 9C Seismic 3D Survey, Midland Basin, West Texas

Imaging faults and fractures with the difference of fast and slow shear-wave splitting reflectivity, Δγ^(S): 3D/9C survey in Midland Basin, West Texas, and 3D/3C survey in Washakie Basin, Wyoming

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Anisotropic multimode joint Rayleigh- and Love-wave inversion

Cited by 3 publications

References 14 publications

Joint wave-equation inversion of Rayleigh and Love dispersion curves

Joint wave-equation inversion of Rayleigh and Love dispersion curves

Shear-wave value for seismic imaging: Lupin 9C Seismic 3D Survey, Midland Basin, West Texas

Imaging faults and fractures with the difference of fast and slow shear-wave splitting reflectivity, Δγ(S): 3D/9C survey in Midland Basin, West Texas, and 3D/3C survey in Washakie Basin, Wyoming

Contact Info

Product

Resources

About

Imaging faults and fractures with the difference of fast and slow shear-wave splitting reflectivity, Δγ^(S): 3D/9C survey in Midland Basin, West Texas, and 3D/3C survey in Washakie Basin, Wyoming