An efficient 3D explicit depth migration

Abstract

An explicit, constrained operator is used for wavefield extrapolation in 3D wave equation depth migration. The migration cost and image quality benefit from its reduced number of independent coefficients, negligible numerical anisotropy, and flexibility that allows for different propagation angles and step sizes in the inline and crossline directions. In order to further reduce the computational workload we dynamically select operator lengths and extrapolation step sizes based on the wavenumber of the wave components being migrated. The phase-shifted linear interpolation that we propose for interpolating the extrapolated wavefield is suitable for the explicit migration, and significantly improves the accuracy of the result when compared with the linear interpolation typically used in implicit migrations.