Seismic Velocity/Statics: A decade of tomography
Marta Jo Woodward, Dave Nichols, Olga Zdraveva, Phil Whitfield, Tony Johns, 2010. "Seismic Velocity/Statics: A decade of tomography", Geophysics Today: A Survey of the Field as the Journal Celebrates its 75th Anniversary, Sergey Fomel
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Over the past 10 years, ray-based postmigration grid tomography has become the standard model-building tool for seismic depth imaging. While the basics of the method have remained unchanged since the late 1990s, the problems it solves have changed dramatically. This evolution has been driven by exploration demands and enabled by computer power. There are three main areas of change. First, standard model resolution has increased from a few thousand meters to a few hundred meters. This order of magnitude improvement may be attributed to both high-quality, complex residual-moveout data picked as densely as 25 m to 50 m vertically and horizontally, and to a strategy of working down from long-wavelength to short-wavelength solutions. Second, more and more seismic data sets are being acquired along multiple azimuths, for improved illumination and multiple suppression. High-resolution velocity tomography must solve for all azimuths simultaneously, to prevent short-wavelength velocity heterogeneity from being mistaken for azimuthal anisotropy. Third, there has been a shift from predominantly isotropic to predominantly anisotropic models, both VTI and TTI. With four-component data, anisotropic grid tomography can be used to build models that tie PZ and PS images in depth.
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“In celebration of the 75th year of publication, the Geophysics editorial team invited a collection of papers written by well-recognized experts in various areas of exploration geophysics. These invited papers not only form part of the present book, but they also appear in the September-October 2010 special section of the journal. Geophysics Today: A Survey of the Field as the Journal Celebrates its 75th Anniversary complements this special section with an additional group of papers, drawn from Geophysics during the recent past, that addresses areas the invited articles did not. The result is a snapshot of the state-ofthe- art in the field as Geophysics passes its three-quarter-century mark. This book is Geophysical References Series No. 16.”