Decoupled equations for reverse time migration in tilted transversely isotropic media
KAUST DepartmentPhysical Sciences and Engineering (PSE) Division
Earth Science and Engineering Program
Earth Sciences and Engineering Program
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AbstractConventional modeling and migration for tilted transversely isotropic (TTI) media may suffer from numerical instabilities and shear wave artifacts due to the coupling of the P-wave and SV-wave modes in the TTI coupled equations. Starting with the separated P- and SV-phase velocity expressions for vertical transversely isotropic (VTI) media, we extend these decoupled equations for modeling and reverse time migration (RTM) in acoustic TTI media. Compared with the TTI coupled equations published in the geophysical literature, the new TTI decoupled equations provide a more stable solution due to the complete separation of the P-wave and SV-wave modes. The pseudospectral method is the most convenient method to implement these equations due to the form of wavenumber expressions and has the added benefit of being highly accurate and thus avoiding numerical dispersion. The rapid expansion method (REM) in time is employed to produce a broad band numerically stable time evolution of the wavefields. Synthetic results validate the proposed TTI decoupled equations and show that modeling and RTM in TTI media with the decoupled equations remain numerically stable even for models with strong anisotropy and sharp contrasts. © 2012 Society of Exploration Geophysicists.
SponsorsThe authors wish to thank King Abdullah University of Science and Technology (KAUST) for providing research funding to this project. We appreciate the reviews by Faqi Liu, Hongbo Zhou, and an anonymous reviewer, who made a number of helpful suggestions that improved the quality of our manuscript. We are also grateful to John Etgen, the associate editor for many useful suggestions. We would like to thank BP for making the TTI model and data set available.
PublisherSociety of Exploration Geophysicists