From Anisotropic Elastic Tensors to Seismic Data and Back: Extraction of Azimuthal Anisotropy Parameters from a Field Sc

Summary Observations of seismic anisotropy in field seismic data are often used to infer fracture properties in the subsurface. To understand if anisotropic elastic parameters can be measured following extensive seismic processing and migration we created a field scale elastic finite difference model simulating a 4-component ocean bottom seismic dataset. The model was built with realistic geological sequences in the overburden and HTI reservoir compartments. Each HTI compartment had different fracture properties (e.g. fracture azimuth and density). Following industry standard methods for denoise and migration we ran post-migration azimuthal velocity and AVOA analysis. Our results find that azimuthal velocities are robust to seismic processing and we appear to be able to measure the input elastic model HTI δ parameter along with the fracture azimuth direction with a reasonable degree of accuracy. Measurements of AVOA are less successful in comparison. Phi azimuth angles compare fairly well with the input model, however the azimuthal anisotropic gradient term shows a poor correlation with the input model.