Patent ID: 6493634
Filing Date: 2002-12-10
Classification: G01V

Abstract:
A method for constructing a velocity model for use in stacking a set of seismic data traces, said method comprising the steps of:(a) separating said set of seismic data traces into a plurality of gathers of seismic data traces; (b) selecting a plurality of velocity analysis locations and, for each such velocity analysis location (1) selecting a group of gathers in the neighborhood of said velocity analysis location, (2) determining a coherence function for said velocity analysis location with respect to a plurality of preselected seismic attributes by calculating the trace-to-trace coherence within each of said selected gathers and the spatial coherence between said selected gathers, said within-gather coherence being calculated at least with respect to seismic moveout velocity and said spatial coherence being calculated at least with respect to reflector dip, (3) determining a set of seismic events for said velocity analysis location by locating all peaks in said coherence function with respect to said preselected seismic attributes, and (4) editing said set of seismic events to determine a subset thereof containing primary reflections only; and (c) adjusting the velocity coordinates of said edited seismic events at said selected velocity analysis locations as needed to produce a smooth velocity model for stacking said set of seismic data traces.