Angle gathers in wave-equation imaging for transversely isotropic media

Alkhalifah, Tariq Ali; Fomel, Sergey B.

Angle gathers in wave-equation imaging for transversely isotropic media

Type

Article

Authors

Alkhalifah, Tariq Ali

Fomel, Sergey B.

KAUST Department

Earth Science and Engineering Program
Environmental Science and Engineering Program
Physical Science and Engineering (PSE) Division
Seismic Wave Analysis Group

Online Publication Date

2010-11-12

Print Publication Date

2011-05

Date

2010-11-12

Abstract

In recent years, wave-equation imaged data are often presented in common-image angle-domain gathers as a decomposition in the scattering angle at the reflector, which provide a natural access to analysing migration velocities and amplitudes. In the case of anisotropic media, the importance of angle gathers is enhanced by the need to properly estimate multiple anisotropic parameters for a proper representation of the medium. We extract angle gathers for each downward-continuation step from converting offset-frequency planes into angle-frequency planes simultaneously with applying the imaging condition in a transversely isotropic with a vertical symmetry axis (VTI) medium. The analytic equations, though cumbersome, are exact within the framework of the acoustic approximation. They are also easily programmable and show that angle gather mapping in the case of anisotropic media differs from its isotropic counterpart, with the difference depending mainly on the strength of anisotropy. Synthetic examples demonstrate the importance of including anisotropy in the angle gather generation as mapping of the energy is negatively altered otherwise. In the case of a titled axis of symmetry (TTI), the same VTI formulation is applicable but requires a rotation of the wavenumbers. © 2010 European Association of Geoscientists & Engineers.

Citation

Alkhalifah, T., & Fomel, S. (2010). Angle gathers in wave-equation imaging for transversely isotropic media. Geophysical Prospecting, 59(3), 422–431. doi:10.1111/j.1365-2478.2010.00930.x