Residual and cascaded migration can be described as a continuous process of velocity continuation in the post-migration domain. This process moves reflection events on the migrated seismic sections according to changes in the migration velocity. Understanding the laws of velocity continuation is crucially important for a successful application of migration velocity analysis. In this paper, I de...

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...

Conventional velocity analysis applied to images produced by wave-equation migration makes use either of moveout information from space-lags, or of focusing information from timelags. However, more robust velocity estimation methods can be designed to take advantage at the same time of the moveout and focusing information provided by the migrated images. Such joint velocity estimation requires ...

To correctly image primary or multiple reflections in a heterogeneous earth, migration reigns supreme, although its computational cost may be nontrivial over complex geology, in 3-D, or when a “true amplitude” image is required. My earlier (Brown, 2002) technique to jointly image primaries and pegleg multiples used normal moveout (NMO), because of NMO’s speed and its amplitude predictability, i...

Differential semblance velocity analysis flattens image gathers automatically by minimizing the mean square difference of neighboring traces in an image volume. Implementations based on normal moveout correction as “imaging” method are relatively fast, can accomodate arbitrary acquisition geometry, and can be organized to output 1D, 2D, or 3D interval velocity models. Within the limits of its i...

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...