Azimuthal seismic dispersion analysis and inversion based on a frequency-dependent fractured model

Wave velocity dispersion and attenuation due to wave-induced fluid flow are important properties for seismic exploration studies of fracture characterization and hydrocarbon identification. Existing seismic inversions are based primarily on an isotropic theory. However, both dispersion and anisotropy should also be considered together. Based on a fracture model describing attenuation, we introduce a frequency-dependent stiffness matrix for azimuthal dispersion analysis, where the dispersion gradient of fracture weakness is a novel fluid indicator. Then, a method of inverting the frequency-dependent amplitude changes with angle and azimuth is proposed to extract the fluid indicator from the seismic data. An inversion test on field data demonstrates the validity of the proposed method.