For increasing time values, isochrons can be regarded as expanding wavefronts and their perpendicular lines as the associated orthogonal isochron rays. The speed of the isochron movement depends on the medium velocity and the source-receiver position. We introduce the term equivalent-velocity to refer to the speed of isochron movement. In the particular case of zero-offset data, the equivalent ...

Velocity continuation is an imaginary continuous process of seismic image transformation in the postmigration domain. It generalizes the concepts of residual and cascaded migrations. Understanding the laws of velocity continuation is crucially important for a successful application of time-migration velocity analysis. These laws predict the changes in the geometry and intensity of reflection ev...

Time migration velocity analysis can be performed by velocity continuation, an incremental process that transforms migrated seismic sections according to changes in the migration velocity. Velocity continuation enhances residual normal moveout correction by properly taking into account both vertical and lateral movements of events on seismic images. Finite-difference and spectral algorithms pro...

In this paper, I apply the migration deconvolution to synthetic seismic images that have been distorted by cable feathering, migration velocity errors and recording geometry variations. The results show that migration deconvolution is able to suppress the velocity and geometry errors and can noticeably improve the quality of the migration image for both 2-D poststack and 3-D prestack migration....

This tutorial describes mixed-domain wave-equation migration and migration velocity analysis techniques in a unified theoretical framework. I review two of the most general mixed-domain migration methods, Fourier finite-difference and generalized screen, and show how other commonly used wave-equation migration methods come about as special cases. I use the Born approximation to derive general e...

This paper presents a method of Stolt residual migration applicable to prestack data. The method’s main merit is that instead of requiring an assumption about the magnitude of the new velocity model to which we want to residually migrate, it only calls for an assumption about the ratio of the reference velocity to the new one. Since the method is, in essence, a Stolt-stretch technique, it inher...