VSP procedures

VSP time section: To obtain a VSP section, the VSP gathers are NMO corrected according to the travel time curve of the down-going wave. No other parameters are needed.

Below is shown a VSP gather before (left) and after (right) NMO correction:

Procedures for VSP data migration: This allows to obtain migrated sections (seismic imaging) which are close to borehole survey by using the weighted Kirchhoff migration procedure. Seismic imaging line could be sour-receiver oriented or arbitrary oriented. The coherence coefficient can be used as a weighting function. The average velocity is used as medium velocity model, which can be obtained either by using near to the well shot point travel times, or by using the down-going wave travel times.

Seismic section (VSP - CDP domain, left), Migrated section (right):