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|Type:||Artigo de periódico|
|Title:||Coherence Measures In Automatic Time Migration Velocity Analysis|
|Abstract:||Time-migration velocity analysis can be carried out automatically by evaluating the coherence of the migrated seismic events in the common-image gathers CIGs. The performance of gradient methods for automatic time-migration velocity analysis depends on the the coherence measures used in the objective function. We compare the results of four different coherence measures, being conventional semblance, differential semblance, an extended differential semblance using more neighboring traces, and the product of the latter with conventional semblance. In our numerical experiments, the objective functions based on conventional semblance and on the product of conventional semblance with extended differential semblance provided the best velocity models, as evaluated by the flatness of the resulting common-image gathers. The method can be easily extended to anisotropic media. © 2011 Society of Exploration Geophysicists.|
|Appears in Collections:||Unicamp - Artigos e Outros Documentos|
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