Geophysical Characterisation of Deep Offshore Prospects in the Niger Delta Deepwater

This study examines the geophysical characterisation of deep offshore exploration prospects in the Niger Delta deepwater, with a focus on seismic interpretation methods for imaging turbidite reservoir systems. The Nigerian deepwater has been one of Africa's most prolific petroleum provinces since the 1990s, hosting giant fields including Bonga, Erha, and Akpo in turbidite reservoir systems at 800 to 2,000 metres water depth. Continued exploration requires sophisticated seismic interpretation tools to identify the remaining deepwater prospects in more complex structural and stratigraphic settings. This study interprets a 3D seismic dataset from the NIPEX public-domain archive for a deepwater exploration block in the eastern Niger Delta. Interpretation includes horizon picking, fault mapping, depth conversion, amplitude extraction, and AVO analysis for fluid prediction. Seismic facies classification using neural network attributes identifies potential turbidite channel and lobe systems. Spectral decomposition maps temporal frequency tuning to delineate reservoir thickness variability. Findings reveal a system of amalgamated turbidite channels and associated levee deposits at 2.2 to 2.8 seconds two-way time, with bright amplitude anomalies interpreted as potential gas sands by Class II AVO response. The channel system shows three-fold complexes of 50 to 150 milliseconds thickness. Spectral decomposition at tuning frequency reveals greater channel complexity than apparent from full-bandwidth data, identifying four discrete channel branches as separate exploration targets. Estimated recoverable resource potential for the principal prospect is 180 to 340 million barrels oil equivalent. The study provides an exploration evaluation workflow for Nigeria's frontier deepwater prospects.

Keywords: deepwater Niger Delta, seismic interpretation, turbidite reservoir, AVO analysis, geophysical characterisation.