Velocity-based Wavelet Corrections for Domain Transformation

It is well established that similar vertical wavelength ranges must be preserved in multicomponent data and that wavelengths of P- and S-waves must match in order to sample reflectivity in an equivalent manner. Conversion of a wavefield to another time or depth domain is described by transformation functions that depend on average VP/VS ratios and velocity. Although these functions align corresponding stratigraphic events of different wavefields, they distort the seismic wavelet because global average velocity properties are independent of local interval properties that define wavelength. In this study we develop a theory of velocity-based wavelet corrections for domain transformations, which are expressed as functions of interval and average VP/VS and velocity, to match wavelength of multicomponent wavefields. We examine the effects for both land and marine data examples and find that land surveys are affected more than marine, and may require spectral broadening of the wavelet. Data from the Marcellus shale in northeast Pennsylvania, USA, shows significant bandwidth improvements for C-waves when wavelet corrections based on velocity match their wavelengths with P-waves. Application of these wavelet corrections should benefit registration fidelity, joint AVO/A (offset and azimuth) inversions and attribute analyses.