A Quantitative Approach to Reconcile Subsalt Images from Overlapping Surveys with Different Geometries

With exploration focusing on more complex targets, there is a high demand for high-quality interpretable seismic images in challenging geological settings such as subsalt areas, combined with an ever increasing interest in multipurpose seismic volumes, adequate for both qualitative and quantitative interpretation. Recent advances in subsalt imaging have focused on qualitative methods to address the main challenge of inadequate subsurface illumination, caused by the complex overburden and seismic acquisition geometry. This paper discusses how point spread functions and depth domain inversion can open the door for new quantitative approaches.

The depth domain inversion workflow is applied to two surveys with different acquisition geometries covering the same area. The survey-specific space-, depth- and dip-dependent illumination effects are captured by the respective grids of point spread functions. The outputs are reflectivity volumes corrected for illumination effects. In areas illuminated by both surveys, the strong similarity between the results obtained independently from each survey proves that this approach removes the survey-specific seismic experiment imprint to unravel the common subsurface response. This opens the door for new quantitative workflows to merge different surveys or partial images and improve both the structural and quantitative interpretability of subsalt images.