Effective wavefield extrapolation in anisotropic media: Accounting for resolvable anisotropy

Handle URI:
http://hdl.handle.net/10754/563513
Title:
Effective wavefield extrapolation in anisotropic media: Accounting for resolvable anisotropy
Authors:
Alkhalifah, Tariq Ali ( 0000-0002-9363-9799 )
Abstract:
Spectral methods provide artefact-free and generally dispersion-free wavefield extrapolation in anisotropic media. Their apparent weakness is in accessing the medium-inhomogeneity information in an efficient manner. This is usually handled through a velocity-weighted summation (interpolation) of representative constant-velocity extrapolated wavefields, with the number of these extrapolations controlled by the effective rank of the original mixed-domain operator or, more specifically, by the complexity of the velocity model. Conversely, with pseudo-spectral methods, because only the space derivatives are handled in the wavenumber domain, we obtain relatively efficient access to the inhomogeneity in isotropic media, but we often resort to weak approximations to handle the anisotropy efficiently. Utilizing perturbation theory, I isolate the contribution of anisotropy to the wavefield extrapolation process. This allows us to factorize as much of the inhomogeneity in the anisotropic parameters as possible out of the spectral implementation, yielding effectively a pseudo-spectral formulation. This is particularly true if the inhomogeneity of the dimensionless anisotropic parameters are mild compared with the velocity (i.e., factorized anisotropic media). I improve on the accuracy by using the Shanks transformation to incorporate a denominator in the expansion that predicts the higher-order omitted terms; thus, we deal with fewer terms for a high level of accuracy. In fact, when we use this new separation-based implementation, the anisotropy correction to the extrapolation can be applied separately as a residual operation, which provides a tool for anisotropic parameter sensitivity analysis. The accuracy of the approximation is high, as demonstrated in a complex tilted transversely isotropic model. © 2014 European Association of Geoscientists & Engineers.
KAUST Department:
Physical Sciences and Engineering (PSE) Division; Earth Science and Engineering Program; Environmental Science and Engineering Program
Publisher:
Wiley-Blackwell
Journal:
Geophysical Prospecting
Issue Date:
30-Apr-2014
DOI:
10.1111/1365-2478.12121
Type:
Article
ISSN:
00168025
Sponsors:
I thank KAUST for its support. I also thank the SWAG group within KAUST for their support. I thank the associate editor, Sergey Fomel, and an anonymous reviewer for their comments and suggestions that helped to improve this paper.
Appears in Collections:
Articles; Environmental Science and Engineering Program; Physical Sciences and Engineering (PSE) Division; Earth Science and Engineering Program

Full metadata record

DC FieldValue Language
dc.contributor.authorAlkhalifah, Tariq Alien
dc.date.accessioned2015-08-03T11:53:22Zen
dc.date.available2015-08-03T11:53:22Zen
dc.date.issued2014-04-30en
dc.identifier.issn00168025en
dc.identifier.doi10.1111/1365-2478.12121en
dc.identifier.urihttp://hdl.handle.net/10754/563513en
dc.description.abstractSpectral methods provide artefact-free and generally dispersion-free wavefield extrapolation in anisotropic media. Their apparent weakness is in accessing the medium-inhomogeneity information in an efficient manner. This is usually handled through a velocity-weighted summation (interpolation) of representative constant-velocity extrapolated wavefields, with the number of these extrapolations controlled by the effective rank of the original mixed-domain operator or, more specifically, by the complexity of the velocity model. Conversely, with pseudo-spectral methods, because only the space derivatives are handled in the wavenumber domain, we obtain relatively efficient access to the inhomogeneity in isotropic media, but we often resort to weak approximations to handle the anisotropy efficiently. Utilizing perturbation theory, I isolate the contribution of anisotropy to the wavefield extrapolation process. This allows us to factorize as much of the inhomogeneity in the anisotropic parameters as possible out of the spectral implementation, yielding effectively a pseudo-spectral formulation. This is particularly true if the inhomogeneity of the dimensionless anisotropic parameters are mild compared with the velocity (i.e., factorized anisotropic media). I improve on the accuracy by using the Shanks transformation to incorporate a denominator in the expansion that predicts the higher-order omitted terms; thus, we deal with fewer terms for a high level of accuracy. In fact, when we use this new separation-based implementation, the anisotropy correction to the extrapolation can be applied separately as a residual operation, which provides a tool for anisotropic parameter sensitivity analysis. The accuracy of the approximation is high, as demonstrated in a complex tilted transversely isotropic model. © 2014 European Association of Geoscientists & Engineers.en
dc.description.sponsorshipI thank KAUST for its support. I also thank the SWAG group within KAUST for their support. I thank the associate editor, Sergey Fomel, and an anonymous reviewer for their comments and suggestions that helped to improve this paper.en
dc.publisherWiley-Blackwellen
dc.titleEffective wavefield extrapolation in anisotropic media: Accounting for resolvable anisotropyen
dc.typeArticleen
dc.contributor.departmentPhysical Sciences and Engineering (PSE) Divisionen
dc.contributor.departmentEarth Science and Engineering Programen
dc.contributor.departmentEnvironmental Science and Engineering Programen
dc.identifier.journalGeophysical Prospectingen
kaust.authorAlkhalifah, Tariq Alien
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