Seismic Attribute-Based Characterization of Heterogeneous Sand Reservoirs in the Niger Delta Basin, Nigeria

Abstract

Accurate characterization of heterogeneous reservoirs in the Niger Delta remains challenging because conventional seismic interpretation alone often fails to resolve complex structural features and lateral variations in reservoir properties. These limitations increase uncertainty in identifying hydrocarbon-bearing intervals and predicting reservoir continuity. This study integrates structural interpretation with seismic attribute analysis to improve reservoir characterization and hydrocarbon prospect identification in the onshore Omicron Field, Niger Delta, Nigeria. High-quality 3D seismic data, check-shot data, and well logs from four wells were integrated to delineate reservoir units, correlate lithologies, interpret faults and horizons, generate time and depth structure maps, and analyse coherency and root-mean-square (RMS) amplitude attributes. Two laterally continuous reservoir sands (Sand A and Sand B) were identified across the field, together with five major faults and two key seismic horizons. Structural interpretation revealed a fault-supported NW–SE-trending anticlinal closure, with structural highs concentrated in the central part of the field and structural lows toward the northwest. RMS amplitude maps show pronounced high-amplitude anomalies in the western part of both reservoirs, indicating potential hydrocarbon accumulation, while Sand B exhibits stronger amplitude responses than the shallower Sand A. The mapped fault-controlled closures and bright-spot anomalies collectively indicate favourable hydrocarbon potential within the study area. The results demonstrate that integrating seismic attributes with structural interpretation reduces uncertainty in reservoir characterization and provides a robust workflow for evaluating heterogeneous reservoirs and identifying exploration targets in the Niger Delta.