Angle-domain illumination gathers by wave-equation-based methods

Abstract:

We present a method for computing the wave-equation-based angle-domain illumination for subsurface structures. It creates subsurface illumination for different scattering or/and dip angles for a given acquisition geometry, velocity model and frequency bandwidth. The proposed method differs from the conventional method in that it does not require local plane-wave decompositions for each source and receiver Green's functions. Instead, it transforms a precomputed subsurface-offset-indexed sensitivity kernel into angle domain using either a Fourier-domain mapping or a space-domain slant stack. We show that the computational cost can be significantly reduced by phase encoding the receiver-side Green's functions, or by simultaneously encoding both the source- and receiver-side Green's functions. Numerical examples demonstrate the accuracy and efficiency of our method. The main anticipated applications of our method are in areas of: (1) accurate amplitude-versus-angle (AVA) analysis by compensating depth-migrated images with angle-dependent illumination, (2) migration velocity analysis that incorporates angle-dependent illumination for robust residual parameter estimation, and (3) optimum seismic survey planning.

Angle-domain illumination gathers by wave-equation-based methods