Effective ellipsoidal models for wavefield extrapolation in tilted orthorhombic media
Type
ArticleKAUST Department
Earth Science and Engineering ProgramPhysical Science and Engineering (PSE) Division
Seismic Wave Analysis Group
Date
2016-08-27Online Publication Date
2016-08-27Print Publication Date
2016-07Permanent link to this record
http://hdl.handle.net/10754/621539
Metadata
Show full item recordAbstract
Wavefield computations using the ellipsoidally anisotropic extrapolation operator offer significant cost reduction compared to that for the orthorhombic case, especially when the symmetry planes are tilted and/or rotated. However, ellipsoidal anisotropy does not provide accurate wavefield representation or imaging for media of orthorhombic symmetry. Therefore, we propose the use of ‘effective ellipsoidally anisotropic’ models that correctly capture the kinematic behaviour of wavefields for tilted orthorhombic (TOR) media. We compute effective velocities for the ellipsoidally anisotropic medium using kinematic high-frequency representation of the TOR wavefield, obtained by solving the TOR eikonal equation. The effective model allows us to use the cheaper ellipsoidally anisotropic wave extrapolation operators. Although the effective models are obtained by kinematic matching using high-frequency asymptotic, the resulting wavefield contains most of the critical wavefield components, including frequency dependency and caustics, if present, with reasonable accuracy. The proposed methodology offers a much better cost versus accuracy trade-off for wavefield computations in TOR media, particularly for media of low to moderate anisotropic strength. Furthermore, the computed wavefield solution is free from shear-wave artefacts as opposed to the conventional finite-difference based TOR wave extrapolation scheme. We demonstrate applicability and usefulness of our formulation through numerical tests on synthetic TOR models. © 2016 Institute of Geophysics of the ASCR, v.v.iCitation
Waheed UB, Alkhalifah T (2016) Effective ellipsoidal models for wavefield extrapolation in tilted orthorhombic media. Studia Geophysica et Geodaetica 60: 349–369. Available: http://dx.doi.org/10.1007/s11200-015-1151-z.Sponsors
We acknowledge KAUST for financial support. We are grateful to Petr Jilek and two anonymous reviewers for their useful comments that helped in improving the quality of the paper.Publisher
Springer NatureJournal
Studia Geophysica et Geodaeticaae974a485f413a2113503eed53cd6c53
10.1007/s11200-015-1151-z