Linearização dos coeficientes de reflexão de ondas qP em meios anisotrópicos

Abstract

The reflection coefficients at a planar interface separating two anisotropic media have a nonlinear dependence on the elastic parameters and densities of both media. Linear approximations on the elastic parameters for the qP wave reflectivity are more convenient for AVO/AVD analysis. We present the solution of the Zoeppritz equations in terms of impedance and polarization matrices. Using this approach and assuming weak impedance contrast and weak anisotropy, a simple derivation of linearized approximations for qP the reflectivity is presented for general anisotropy. The linear approximations of reflection coefficients, qP and converted waves, for qP incidence are very close to the exact results for incidence angles up to 30 degrees considering moderate impedance contrast and anisotropy.