Wavefield extrapolation in pseudodepth domain

Published as Geophysics, 78, no. 2, S81-S91, (2013)

Wavefield extrapolation in pseudodepth domain

Xuxin Ma and Tariq Alkhalifah
Physical Sciences and Engineering Division
King Abdullah University of Science and Technology
Thuwal 23955-6900, Saudi Arabia

Abstract:

Wavefields are commonly computed in the Cartesian coordinate frame. Its efficiency is inherently limited due to spatial oversampling in deep layers, where the velocity is high and wavelengths are long. To alleviate this computational waste due to uneven wavelength sampling, we convert the vertical axis of the conventional domain from depth to vertical time or pseudo depth. This creates a nonorthognal Riemannian coordinate system. Both isotropic and anisotropic wavefields can be extrapolated in the new coordinate frame with improved efficiency and good consistency with Cartesian domain extrapolation results. Prestack depth migrations are also evaluated based on the wavefield extrapolation in the pseudodepth domain.