Characterization of VTI media with P-Sv AVO attributes

Amplitude variation with offset (AVO) signatures in vertically transverse isotropic (VTI) media vary as the degree of the anisotropy contrast varies between layers. When the values of two parameters (δ and e) that quantify the VTI elastic anisotropy are varied, the fraction of energy that reflects from a given layer interface as a modeconverted shear wave (RPS ) also varies for specified angles of incidence. Mode-converted AVO crossplots might potentially be used to map stratigraphic layers exhibiting intrinsic VTI with the moderate to high degrees of weak elastic anisotropy that are often associated with shale formations. When the parameter δ varies from -0.06 to 0.1, some spread can be observed on a mode-converted AVO crossplot. Therefore, AVO attribute maps might be capable of delineating the degree of anisotropy present in subsurface rocks. Additionally, using this mode-converted AVO information in conjunction with PP, SV-SV, and SH-SH AVO crossplot analysis might increase the confidence in sweet spot delineation for organic shale formations.