Curved rays anisotropic tomography: Local and global approaches

Zvi Koren, Igor Ravve, Dan Kosloff

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

Abstract

Curved Rays Tomography updates background anisotropy velocity parameters in the time-migrated domain. The tomography uses image gathers generated by Anisotropy Curved Rays Kirchhoff Time Migration. A locally varying 1D Vertical Transverse Isotropy (VTI) model is assumed. The background anisotropy parameters are the instantaneous (interval) vertical compression velocity V and the two Thomsen anisotropy parameters d and e . Interval velocity (or alternatively d ) is updated from short offsets reflection events, while e is updated from the available long offset data. Two complementary approaches are presented in this study: local and global. In the local approach, the medium parameters are updated from top down, layer by layer, one parameter at a time. The residual anisotropy parameters, that best fit the residual moveout curves, are picked. The residual moveout includes overburden and current layer components. In the global approach, all parameters are inverted simultaneously. Due to a large number of offsets, the problem becomes over-defined, and we solve it by a constrained least-squares minimization. The cost function accounts for data and model variances, which reflect the reliability of the data and control parameter variations, respectively. The updated parameters are constrained to a feasible range.

Original languageEnglish
Title of host publicationSociety of Exploration Geophysicists - SEG International Exposition and 76tth Annual Meeting 2006, SEG 2006
PublisherSociety of Exploration Geophysicists
Pages3373-3377
Number of pages5
ISBN (Print)9781604236972
StatePublished - 2018
EventSociety of Exploration Geophysicists International Exposition and 76tth Annual Meeting 2006, SEG 2006 - New Orleans, United States
Duration: 1 Oct 20066 Oct 2006

Publication series

NameSociety of Exploration Geophysicists - SEG International Exposition and 76tth Annual Meeting 2006, SEG 2006

Conference

ConferenceSociety of Exploration Geophysicists International Exposition and 76tth Annual Meeting 2006, SEG 2006
Country/TerritoryUnited States
CityNew Orleans
Period1/10/066/10/06

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