True amplitude weights for converted-wave prestack migration

摘要

Preserving amplitudes in converted-wave prestack migration is important for subsequent AVO processing and interpretation. However, it has not received as much attention as amplitude preservation for P wave migration. In this paper, we derive common offset true amplitude weight functions in a v(z) medium for 2. 5D and 3D converted-wave Kirchhoff migration. The weight formulas are then simplified into terms involving travel time, ray path and velocity functions for efficient computation. The simplified weight functions are also examined with numeric modeling data for depth migration, which demonstrates well controlled amplitude behavior in offset and depth.