Numerical analysis of 2.5-D true-amplitude diffraction stack migration

By considering arbitrary source-receiver configurations, compressional primary reflections can be imaged into time or depth-migrated seismic sections so that the migrated wavefield amplitudes are a measure of angle-dependent reflection coefficients. Several migration algorithms were proposed in the recent past based on the Born or Kirchhoff approach. All of them are given in form of a weighted diffraction-stack integral operator that is applied to the input seismic data. The result is a migrated seismic section where at each reflection point the source wavelet is reconstructed with an amplitude proportional to the reflection coefficient at that point. Based on the Kirchhoff approach, we derive the weight function and the diffraction stack integral operator for a two and one-half (2.5-D) seismic model and apply it to a set of synthetic seismic data in noisy environment. The result shows the accuracy and stability of the 2.5-D migration method as a tool for obtaining important information about the reflectivity properties of the earth's subsurface, which is of great interest for amplitude vs. offset (angle) analysis. We also present a new application of the Double Diffraction Stack (DDS) inversion method to determine three important parameters along the normal ray path, i.e., the angle and point of emergence at the earth surface, and also the radius of curvature of the hypothetical Normal Incidence Point (NIP) wave. (C) 2000 Elsevier Science B.V. All rights reserved.