A robust scheme to output angle-domain common image gathers for shot-profile migration

Summary

Angle-domain common image gathers (CIGs) play an important role in migration-based velocity updating. One popular criterion of migration velocity analysis (MVA) is the flatness of common-angle image gathers. We first revisit the popular schemes of generating angle-domain CIGs by wavefield continuation migration. Then, we present an alternative approach to produce commonangle image gathers. Our method, one of multiple-weight methods, is also for shot-profile migration based on oneway wave equation. To avoid the stability problem of multiple-weight methods, our scheme is implemented in complex number domain for every frequency after imaging. The ability of anti-alias resulted from sparse shot geometry is investigated. Numerical examples show that our strategy is efficient, stable, and easy to implement.

Key words::

• angle-domain common image gathers
• oneway wave equation
• shot-profile migration
• sparse shot geometries