Fast automatic wave-equation migration velocity analysis using encoded simultaneous sources

Fast automatic wave-equation migration velocity analysis using encoded simultaneous sources

Yaxun Tang

Abstract:

I present a method based on source encoding for fast wave-equation migration velocity analysis (WEMVA). Instead of migrating each impulsive-source gather separately, I assemble all gathers together and migrate only one super shot gather. This procedure results in the computational cost of WEMVA to be independent from the number of impulsive-source gathers, which is typically huge for large surveys. The proposed encoding method can be applied to data acquired from any acquisition geometry, such as land or marine acquisition geometries. The velocity inversion is done automatically by solving a nonlinear optimization problem that maximizes the image stack power, which is shown to be equivalent to the data-domain inversion using only primary reflections. Preliminary results show that WEMVA with encoded sources can produce inversion results similar to those produced by conventional separate-source WEMVA, but with drastically reduced computational cost.

Fast automatic wave-equation migration velocity analysis using encoded simultaneous sources