VSP Imaging by Wave-field Extrapolation Technique

Abstract

Imaging of Vertical Seismic Profile (VSP) data is routinely performed using Pre-stack Depth Migration (PSDM) processing. This approach requires an accurate subsurface velocity model, which is not always available, particularly in complex geological environments. In this work, we present a procedure to accurately image the subsurface by using common image gathers to update the velocity model. Using a wave-field extrapolation technique, the up-going and the down-going wave-fields from the VSP data are converted into a pseudo surface seismic dataset, while preserving the relative amplitudes and fidelity of the VSP data. Once transformed to the surface domain, the whole range of surface seismic imaging algorithms can be utilized to produce a more accurate subsurface image. Synthetic and real walk-away VSP data examples have shown significant improvements in the imaging quality when wave-field extrapolation is used compared to regular VSP data processing techniques. This technology will help to exploit the full potential of the VSP data.