Migration scheme for imaging offset VSP data within local phase space

Abstract

The imaging of offset VSP data in local phase space can improve the image of the subsurface structure near the well. In this paper, we present a migration scheme for imaging VSP data in a local phase space, which uses the Gabor-Daubechies tight framebased extrapolator (G-D extrapolator) and its high-frequency asymptotic expansion to extrapolate wavefi elds and also delineates an improved correlation imaging condition in the local angle domain. The results for migrating synthetic and real VSP data demonstrate that the application of the high-frequency G-D extrapolator asymptotic expansion can effectively decrease computational complexity. The local angle domain correlation imaging condition can be used to weaken migration artifacts without increasing computation.

Imaging of vertical seismic profiling data using weighted generalized radon transform migration in dip-angle domain

“…Lou et al (2009) attenuated migration smiles and artifacts of VSP images by defining and selecting an appropriate migration aperture angle. Zhou et al (2010) used a local-angle-domain correlation imaging condition to attenuate migration artifacts. Lou and Simpson (2019) presented an efficient and effective dip filter consistent with the local velocity model in VSP migration, which preserves true dip structures, and in the meantime suppresses migration artifacts.…”