Patent ID: 7508735
Filing Date: 2009-03-24
Classification: G01V

Abstract:
1. A method of analyzing vertical seismic profile data, the method comprising obtaining a multi-offset vertical seismic profiling data set comprising a representation of a wave-field recorded by an array of multi-component seismic receivers; extracting a P-wave slowness-polarization data set from the multi-offset vertical seismic profiling data set, the P-wave slowness-polarization data set resolving P-wave slowness against P-wave polarization angle relative to a reference direction; selecting a function relating P-wave polarization angle to P-wave slowness, the selected function being dependent on at least three free parameters, wherein in at least two of these free parameters information of shear wave velocity is absorbed together with one or more anisotropy parameters descriptive of formation anisotropy; and finding regression values for the at least three free parameters by fitting the selected function to the P-wave slowness-polarization data set; wherein the selected function is derived in a weak anisotropy approximation, and wherein the selected function is derivable from  summed over all combinations of values 1, 2, and 3 for repeated indices i, j, k, and l, wherein the values 1, 2, and 3 represent three orthogonal directions, wherein