Patent ID: 7706211
Filing Date: 2010-04-27
Classification: G01V

Abstract:
1. A method of determining a seismic velocity, comprising steps of: (a) providing two or more seismic receivers in the subsurface formation at predetermined distances from one another; (b) selecting a seismic receiver m from the two or more seismic receivers as the location of a virtual source; (c) selecting another seismic receiver k from the two or more seismic receivers; (d) activating a seismic source at a location n, thereby exciting a wave in the subsurface formation; (e) recording a wave signal trace u (f) recording a wave signal trace u (g) cross correlating the wave signal traces u (h) repeating steps (d) to (g) inclusive, for different locations n; (i) summing u (j) deriving the seismic velocity based on the time of first arrival of the wave in u