KAUST DepartmentPhysical Sciences and Engineering (PSE) Division
Earth Science and Engineering Program
Permanent link to this recordhttp://hdl.handle.net/10754/625252
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AbstractWavefield tomography can handle complex subsurface geology better than ray-based techniques and, ultimately, provide a higher resolution. Here, we implement forward and adjoint wavefield extrapolation for VTI (transversely isotropic with a vertical symmetry axis) media using a pseudospectral operator that employes a separable approximation of the P-wave dispersion relation. This operator is employed to derive the gradients of the differential semblance optimization (DSO) and modified stack-power objective functions. We also obtain the gradient expressions for the data-domain objective function, which can incorporate borehole information necessary for stable VTI velocity analysis. These gradients are compared to the ones obtained with a space-time finite-difference (FD) scheme for a system of coupled wave equations. Whereas the kernels computed with the two wave-equation operators are similar, the pseudospectral method is not hampered by the imprint of the shear-wave artifact. Numerical examples also show that the modified stack-power objective function produces cleaner gradients than the more conventional DSO operator.
CitationLi V, Wang H, Tsvankin I, Diaz E, Alkhalifah T (2016) Gradient computation for VTI acoustic wavefield tomography. SEG Technical Program Expanded Abstracts 2016. Available: http://dx.doi.org/10.1190/segam2016-13967436.1.
SponsorsThis work was supported by the Consortium Project on Seismic Inverse Methods for Complex Structures at CWP and competitive research funding from King Abdullah University of Science and Technology (KAUST).
PublisherSociety of Exploration Geophysicists
Conference/Event nameSEG International Exposition and 86th Annual Meeting, SEG 2016