|Wide-azimuth angle gathers for wave-equation migration|
Angle decomposition based on wavefield extrapolation methods is
characterized by robustness in areas with sharp velocity variation and
by accuracy in the presence of steeply dipping reflectors.
Extended common-image-point gathers constructed at discrete image
points provide sufficient information for angle decomposition. The
decomposition is based on the planar approximation of the source and
receiver wavefields in the immediate vicinity of the image
Both space-lag and the time-lag extensions are required to completely
characterize the reflection geometry given by the local reflection and
azimuth angles. However, assuming that information about the reflector
slope is available, we could avoid computing one lag of the extended
image, usually the vertical. This increases the computational
efficiency of the method and makes it affordable for large-scale
wide-azimuth imaging projects.