Azimuthally anisotropic 3D velocity continuation

Velocity continuation describes how a seismic image changes given a change in migration velocity. This description turns out to be a wave propagation process, in which images propagate along a velocity axis. In the anisotropic case, the velocity model is multi-parameter. Therefore, anisotropic image propagation is multi-dimensional. We extend time-domain velocity continuation to the 3D azimuthally anisotropic case. We use a three-parameter slowness model, which can be related to azimuthal variations in velocity, as well as their principal directions. This information is useful for fracture and reservoir characterization from seismic data. We provide synthetic diffraction imaging examples to illustrate the concept of azimuthal continuation and to analyze the impulse response of the 3D velocity continuation operator.