In this particular geometry, the wells are not confined to a single plane. Instead, they deviate gradually form the vertical plane that contains both wells at the near surface. We have taken this effect into account following this two-steps procedure:
When correcting for the well deviation in this way, true source-receiver separations are used in the inversion. The relative position of the two wells after considering the deviation is shown in Figure 10. To use the true distances, it is necessary to move the receivers positions horizontally in the deviated well. This is way the receiver positions in Figure look like horizontally smeared. The selection of the vertical well used as a reference to measure the relative deviations is irrelevant if we assume that the model is 1-D. In 2-D somewhat different distorsions may occur depending on which well is chosen as a reference.