Walker Ridge, Gulf of Mexico

The 3D SJI workflow started from an existing seismic reflection tomographic model—illustrated in the first image of the adjacent expandable graphic—from which we removed a portion of the salt (top right model) obtaining the initial velocity model and ran several iterations of targeted 3D SJI with reflection seismic and (marine magnetotelluric) MMT data, obtaining the final SJI velocity model (bottom right model) together with its corresponding resistivity model. The bottom left model shows how the 3D SJI has led to a new 3D interpretation of the allochthonous salt base (colored) and positioning of the autochthonous top salt (blue).

The second image of the adjacent expandable graphic features legacy wave-equation migration overlaid by the velocities obtained with the legacy reflection tomography (left), and the new SJI velocity model (middle: updates from initial model, blue is low and red is high update) with interpretations (right).

The high velocity of autochthonous salt is absent in the single-domain velocity model (left) and present only in the SJI velocity model (middle and right) given the MMT capability of seeing the resistive salt anomaly.