Robust estimation of vertical symmetry axis models via joint migration inversion: Including multiples in anisotropic parameter estimationAnisotropic joint migration inversion

Abstract

Since the Earth is predominately anisotropic, the anisotropy of the medium needs to be included in seismic imaging to avoid mispositioning of reflectors and unfocused images. Deriving accurate anisotropic velocities from the seismic reflection measurements is a highly nonlinear and ambiguous process. To mitigate the nonlinearity and trade-offs between parameters, we propose to include anisotropy in the so-called Joint Migration Inversion (JMI) method, where we limit ourselves to the case of transverse isotropy with a vertical symmetry axis (VTI). The JMI method is based on strictly separating the scattering effects in the data from the propagation effects. The scattering information is encoded in the reflectivity operators, while the phase information is encoded in the propagation operators. This strict separation enables the method to be more robust, in that it can appropriately handle a wide range of starting models …