Patent ID: 7117093
Filing Date: 2006-10-03
Classification: G01V

Abstract:
1. A method for producing an initial velocity field estimate for a control plane from seismic data associated with said control plane and comprising time-amplitude representations associated with source-receiver locations spaced apart by an offset distance and having a midpoint therebetween, the seismic data being arranged into common midpoint (CMP) gathers associated with respective CMP locations and the control plane having an edge intersecting a plurality of the CMP locations, the method comprising: a) producing a starting velocity field estimate from an initial range of velocity values and an initial range of time values; b) producing a migrated starting velocity field from said starting velocity field estimate and said seismic data; c) producing pre-stack imaged gathers by performing a 2-dimensional pre-stack imaging process on said seismic data; d) producing normal moveout gathers in response to said migrated starting velocity field, including performing a normal moveout operation on said pre-stack imaged gathers; e) adjusting said migrated starting velocity field in response to said normal moveout gathers and said migrated starting velocity field to produce a plurality of time-velocity values for each of the OMP locations, said plurality of said time-velocity values acting as said initial velocity field.