VSP Velocity Analysis Using a Phase Spectral Method

F-41 VSP VELOCITY ANALYSIS USING A PHASE SPECTRAL METHOD Abstract 1 This paper presents a phase spectral method for VSP velocity analysis based on Fourier time-shift theorem. A borehole seismic velocity survey was analyzed using this approach. This phase spectral method accurately measures the differential times between VSP receivers at different frequencies. Travel times were found to vary with frequency. This may explain time-tie mismatches between VSP and surface seismic data in some areas. Further phase spectral analysis is able to quantify the seismic velocity dispersion in the medium. These dispersion curves were used to estimate the quality factor Q.