Refining prospect extent in a faulted deltaic reservoir through integrated structural interpretation and seismic attributes: evidence from Field-X, Rio Del Rey Basin, Cameroon

Abstract Field-X in the western offshore Rio Del Rey Basin, Cameroon, is a faulted deltaic prospect where structural segmentation and lateral variations in seismic character create uncertainty in defining the effective extent of reservoir-bearing intervals. This study integrates fault interpretation, horizon mapping, depth conversion, and horizon-constrained seismic attributes to evaluate prospect extent within three reservoir-equivalent intervals (S.7 C, S.8 C, and S.9 A) using an approximately 5 km² 3D seismic volume extending to 3.0 s two-way travel time. The mapped horizons were depth-converted using well-calibrated pseudo-velocity surfaces, while amplitude, spectral decomposition, and similarity attributes were used to assess fault segmentation, reflector continuity, and possible stratigraphic termination. Results show that Field-X is divided into several fault-bounded compartments rather than forming a single continuous structural closure. Reflector packages are more continuous in the central and western parts of the field but become weaker, thinner, or terminate toward the eastern and southern margins. Of the three intervals evaluated, S.8 C displays the strongest and most laterally coherent attribute response and defines the clearest seismic-supported fairway, whereas S.7 C shows weak and localized responses and S.9 A contains smaller anomalies distributed among several fault-bounded compartments. Structural disturbance and reduced reflector continuity are also observed adjacent to the possible shale diapir. The results demonstrate that mapped structural closure alone can overestimate prospect extent where reflector continuity is not maintained. The main contribution of this study is therefore the demonstration that integrating structural geometry with reflector continuity and horizon-constrained seismic attributes provides a more constrained definition of effective prospect extent than structural mapping alone in faulted deltaic reservoirs.