Evaluation of Seismic Attribute Applications for Reservoir Characterisation in the Coastal Swamp Depobelt, Western Niger Delta

Seismic attribute analysis has become an indispensable tool for sub-surface characterisation in the highly channelised and structurally complex depositional systems of the Niger Delta. This study evaluates the application of post-stack seismic attributes including acoustic impedance inversion, sweetness, and amplitude versus offset response for reservoir characterisation in the Coastal Swamp Depobelt of the Western Niger Delta, offshore Bayelsa and Delta States. A 3D seismic dataset over a producing field block was used to compute and interpret multiple seismic attributes in relation to known well penetrations. Coloured inversion was applied to derive acoustic impedance volumes, which were cross-plotted against wireline-derived porosity logs to establish a robust petrophysical transform. Sweetness attribute maps generated by dividing the envelope attribute by the instantaneous frequency were validated against reservoir sand thickness maps from well-to-well correlations. Amplitude versus offset class II anomalies were identified in three prospective intervals, correlating with known hydrocarbon columns in existing wells. The combination of acoustic impedance and sweetness attributes correctly predicts net pay thickness within plus or minus 15 percent across six blind well tests. The study demonstrates that integrated multi-attribute analysis reduces exploration risk in stratigraphically complex environments typical of the Coastal Swamp Depobelt and recommends a structured attribute selection workflow for future characterisation campaigns. Keywords: seismic attribute, reservoir characterisation, Niger Delta, acoustic impedance, coastal swamp depobelt.