Estimativa de modelo de velocidade em profundidade a partir de velocidades de migração em tempo
One of the major challenges to seismic imaging in complex geological regions is velocity model building in depth. If lateral variation in the propagation velocity is moderate, a depth velocity model can be build starting from time migration velocities. I review the theoretical relation between th...
| Autor principal: | VALENTE, Leandro da Silva Sadala |
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| Grau: | Trabalho de Conclusão de Curso - Graduação |
| Publicado em: |
2019
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| Assuntos: | |
| Acesso em linha: |
http://bdm.ufpa.br/jspui/handle/prefix/1752 |
| Resumo: |
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One of the major challenges to seismic imaging in complex geological regions is velocity
model building in depth. If lateral variation in the propagation velocity is moderate,
a depth velocity model can be build starting from time migration velocities. I review the
theoretical relation between these velocities using the paraxial ray theory. The estimation
of depth velocities from time migration velocities is unstable. I implement regularized versions
of the time to depth conversion based on Dijkstra-like fast marching methods. Two
more e cient variations from the original algorithm proposed recently in the literature
are evaluated. The relation between the polynomial degree and the regularization value
for the least-squares problem associated with the wavefront interpolation are determined.
Finally, I test these algorithms on 2D synthetic data and compare the results obtained by
three ray tracing algorithms. |