Azimuth anisotropy prediction and correction of wide-azimuth seismic data

Abstract

For seismic wave propagation in HTI media, both kinematic and dynamic attributes are anisotropic. P-waves run slower in the direction perpendicular to fracture azimuth than in the direction parallel to fracture azimuth; meanwhile, reflection strength and frequency vary with azimuth. We quantitatively analyzed azimuthal effects of reflection coefficients and velocities of seismic waves in HTI medium. The anisotropy on the azimuth gathers from theory and real wide-azimuth data was studied as well. Therefore, ellipse fitting was performed to quantitatively predict the direction and strength of the anisotropy in the study area, which was consistent with that obtained by the shear wave splitting prediction method. In wide azimuth data processing, in order to eliminate the influence of azimuthal anisotropy, the coherent spectrum pickup method was utilized to accurately calculate the azimuthal velocity of underground HTI media, and conducts azimuthal anisotropy correction processing, which eliminates the fast and slow wave time difference caused by azimuthal anisotropy, and achieves good results, providing a support for subsequent high-resolution imaging.