Increasing confidence in reef interpretation using dip angle gathers analysis

The uncertainty associated with the seismic interpretation of carbonate reef boundaries primarily relates to the generally limited difference between the velocities characterizing the reef body, and those of the encasing strata. In addition, the carbonate overburden section also generates strong multiple waves, whose physical characteristics are similar to those of the primary reflections, hindering the unequivocal identification of the latter. As a result, through conventional processing, it is often difficult to achieve a high signal-to-noise ratio and to confidently define the reef boundaries. Even employing industry-established, traditional seismic attributes a reef may just appear as a faint shadow or even not be visible. For a more confident interpretation of the reef we propose the adoption of an advanced methodology, based on analysis of dip angle gathers. Such an approach allows for a straightforward and reliable identification of the reef edges, reducing the uncertainties connected with their interpretation and possibly highlighting areas of different reservoir properties.