The relative efficiency of Common Azimuth wave equation depth migration based on the double square root equation makes it an attractive engine for use in automated velocity updating schemes. One such automated velocity analysis procedure is Differential Semblance Optimization, which constructs velocity updates to reduce, and eventually minmize, a quantitative measure of image gather misfocussin...

Diierential semblance is unique amongst velocity inversion objectives in having well-deened and smooth high frequency asymptotics. A version appropriate for analysis of CMP gathers and layered models is particularly easy to analyse and economical for numerical experimentation. For model-consistent data, the DS objective measures the error in RMS velocity, weighted by the energy in the data-with...

the purpose of velocity analysis is to extract the normal moveout velocity as a function of the zero-offset travel time at selected cdp locations along the seismic line. since results of velocity analysis depend on coherency estimator, an estimator that provides a high velocity resolution is essential. even though the conventional semblance method which is the most popular coherency estimator (...

Prestack wave equation migration using the double square root equation produces prestack image volumes free of artifacts, even in the presence of multipathing due to complex structure. In particular image gathers in angle or offset ray parameter are flat at correct velocity, and gathers in offset are concentrated at zero offset. Differential semblance measures the deviation from flatness or con...