Patent ID: 6785612
Filing Date: 2004-08-31
Classification: G01V

Abstract:
A method of updating, in a CPU, velocity determinations for anisotropic P-P and P-S prestack depth migration in a transversely isotropic media with vertical symmetry, which comprises:identifying corresponding reflections from P-P and P-S near-offset seismic waves received from a seismic source and reflected by a subsurface layer to form P-P and P-S depth consistent image gathers; performing a joint velocity inversion in depth on said P-P and P-S depth consistent image gathers to estimate a vertical depth zo, a vertical P-wave velocity vpo, and a vertical S-wave velocity vso of said subsurface layer; determining an isotropic depth migration of P-P depth consistent image gathers comprising said depth consistent image gathers based upon said vertical depth zo, said vertical P-wave velocity vpo, and said vertical S-wave velocity vso to estimate vertical isotropic depth zpp of said subsurface layer; calculating anisotropic parameters &dgr; and &sgr; based upon said vertical isotropic depth zpp, said vertical P-wave velocity vpo, and said vertical S-wave velocity vso; and repeating the above steps beginning with the step of performing a joint velocity inversion in depth until said vertical P-wave velocity vpo and said vertical S-wave velocity vso are substantially unchanged.