Recuperação de propriedades acústicas da subsuperfície através da inversão sísmica por mínimos quadrados linear e não linear

• Ano de defesa: 2019
• Autor(a) principal: Bautista, Kristian David Torres
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal do Rio de Janeiro; Brasil; Instituto Alberto Luiz Coimbra de Pós-Graduação e Pesquisa de Engenharia; Programa de Pós-Graduação em Engenharia Civil; UFRJ
• Palavras-chave em Português: FWI; LSRTM; Inversão; Geofísica computaciona; CNPQ::ENGENHARIAS::ENGENHARIA CIVIL
• Link de acesso: http://hdl.handle.net/11422/14079

In this work, the inverse problem of exploration geophysics is solved through two techniques based on the minimization of the least squares objective function. The nonlinear problem that estimates the acoustic velocity of the medium is solved by seismic full waveform inversion. For this, two multiscale strategies were considered in order to mitigate the nonlinearity of the problem. In addition, a preconditioner term that approximates the inverse of the Hessian matrix is contemplated to assist in the imaging of the deeper parts of the model and improve the convergence of the optimization algorithm. On the other hand, the linear inverse problem that recovers the true subsurface reflectivity model is solved by the least squares reverse time migration. The numerical examples performed here demonstrate that the inverse operator of the migration problem (implicitly estimated by an iterative solver), has deconvolutive properties, and thus, it can be used to obtain improved seismic sections with better resolution and reflectors with more balanced amplitudes.