Computing pseudo-crosswell data by using seismic interferometry with sources on the surface

Adriana Gordon, Raul Cova, Kristopher A. Innanen

Seismic interferometry is a method based on the use of cross correlation and stacking operations to redatum seismic data. The special case of vertical seismic profile (VSP) in a cross-well configuration is the interest of this paper. We present an approach using seismic interferometry to compute pseudo-cross-well information. This study shows an analysis of the aperture effect and fold distribution for direct waves, and full wavefield interferometry at four different maximum offsets. Results indicate that where the maximum offset increases the match between raytraced traveltimes and the interferometric receiver gathers improves. Using direct arrivals it was only possible to retrieve traveltimes at receivers in a lower position on the second well. However, using reflected arrivals provided traveltimes for receiver at a shallower depth in the second well. Thus, use of the full wavefield displays a more complete result. The interferometric fold distribution showed a similar result; as the maximum offset increases the fold is improved and reaches deeper parts of the model. This type of processing may help to generate data suitable to exploit the benefits of the cross-well experiment without the risks involved in the acquisition.