Estimativa de Parâmetros de Anisotropia pela Inversão de Levenberg-Marquardt

In this study we investigate the applicability of the Levenberg-Marquardt inversion technique, also called damped least squares for the purpose of estimating the NMO velocity and the Thomsen anisotropy parameters. We used and compared more recent and accurate approximations for the computation of the reflection time of the P wave in a medium with VTI anisotropy. The inversion results for different models have shown that for small values of | | the approaches are accurate, in particular the approximations of Tsvankin and Thomsen (1994) and Fomel (2004). Also, the inversion simulations have shown that the errors in estimated NMO velocity and estimated Thomsen parameters increase when the condition 0.2 | | is used. In this situation the Fomel (2004) approximation gives the smallest errors when compared to other approaches.