Nonlinear amplitude variation with offset and azimuth inversion for horizontal transverse isotropic media based on the elastic stiffness matrix

Transverse isotropy with a horizontal axis of symmetry (HTI) media is generally considered as parallel vertical cracks embedded in an isotropic matrix or vertically dipping shale sequences and is widely used in unconventional hydrocarbon exploration. Inversion of anisotropy parameters for HTI media is important for characterizing fractures and filled fluids. However, owing to the added azimuthal dimension and small contribution of anisotropic parameters, achieving stable inversion of anisotropy parameters from azimuthal seismic data is challenging. A nonlinear amplitude variation with offset and azimuth inversion is developed to address this issue, indirectly predicting the anisotropy using the stiffness matrix. First, P, SV, and SH exact elastic impedance matrices for HTI media characterized by the stiffness matrix are derived from Hooke's law and used to