P-wave reflectivity parameterization for HTI medium with the effect of horizontal stress

Abstract

P-wave reflectivity parameterization for transversely isotropic medium with a horizontal axis of symmetry (HTI medium) with the effect of initial stress plays an important role in in-situ stress inversion, fracture characterization and safe production. In this work, we propose a linearized P-wave reflectivity equation of HTI medium under horizontal stress to associate seismic signals and horizontal stress. Utilizing the solid acoustoelasticity theory, we decouple the seismic anisotropy into the horizontal stress-induced anisotropy and vertical fracture-induced anisotropy to distinguish the effect of stress and fracture on P-wave reflectivity. First, we investigate the effect of horizontal stress on AVAZ characteristic. Then the sensitivity of P-wave reflectivity to five anisotropic parameters is analyzed. Furthermore, we establish a horizontal stress inversion operator by utilizing difference of P-wave reflection coefficients at different azimuths. Model examples illustrate the accuracy and robustness of our proposed linearized P-wave reflectivity equation and horizontal stress inversion operator at small incident angle.