Table‐Driven 3‐D Angle‐Domain Imaging Approach for Kirchhoff Prestack Time Migration

Abstract

To overcome some of the shortages of conventional Kirchhoff presatck time migration technique and to provide more powerful supports for amplitude versus incidence‐angle and azimuth (AVA/AVAZ) analysis, we develop a 3‐D angle‐domain imaging approach based on the classical ray tracing equations in laterally homogeneous media. Numerical tables of one‐way travel times and take‐off angles of rays are firstly established by a modified raytracing algorithm. Once the two‐way travel times, weighted factors, average azimuth and local incidence angles at the reflectors are estimated, 3‐D structural images and angle‐domain common‐image gathers are generated through superposition of impulse responses in the process of Kirchhoff migration. Unlike the conventional approach, the implementation of this method has taken ray bending and propagation property of seismic waves in 3‐D lateral invariant media into account. As a result, it helps to extract variations of amplitude and moveout versus azimuth and incidence‐angle more accurately. Synthetic and real data examples demonstrate the advantage and practicability of this technique.