Banca de QUALIFICAÇÃO: RENATO RAMOS DA SILVA DANTAS

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
DISCENTE : RENATO RAMOS DA SILVA DANTAS
DATA : 27/07/2017
HORA: 09:00
LOCAL: Auditório DGEF
TÍTULO:

FWI INVERSION WITH WAVEFORM, ENVELOPE AND PHASE FUNCTIONALS

PALAVRAS-CHAVES:

Seismic Inversion, Full Waveform Inversion, Hilbert Transform

PÁGINAS: 58
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Geociências
RESUMO:

Full waveform inversion (FWI) is a technique that achieves excellent resolution in velocity models. However, its classic waveform functional have multiple local minimum. This problem makes FWI very dependent on the starting model. Moreover, the starting model needs to have a good content of long wavelengths. In order to mitigate these limitations, a popular approach has been to replace the classic waveform functional by other functionals. In this document, using the Marmousi model, we test the functionals of envelope and instantaneous phase of the seismic trace under accoustic approximation, with uniform density, and we compare them with the waveform functional. We used a 3 Hz linear source, supplying enough low frequency content so that it doesn’t become an issue to waveform inversion.  The results prove that the envelope is sensitive to smooth model features, and the phase is sensitive to the model reflectivity. A sequential inversion, starting with envelope and ending with phase, leads to a great resolution improvement and removes some artifacts. No functional was able to fit intermediary time reflections, likely because the transmitted component energy of the seismic trace dominates the reflected component energy. We are testing methodologies to mitigate this issue.

MEMBROS DA BANCA:
Interno - 1451214 - ADERSON FARIAS DO NASCIMENTO
Interno - 1863578 - JORDI JULIA CASAS
Presidente - 349684 - WALTER EUGENIO DE MEDEIROS