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

Abstract

Abstract This study successfully predicted the presence of hydrocarbon-bearing reservoirs in an onshore Niger delta field by combining structural interpretation and seismic attribute analysis. Check-shot data, high-quality 3D seismic data, and four wells log data with requisite petrophysical logs were employed. The approach involved identifying various lithologies from gamma ray and resistivity logs, correlating wells, mapping faults and horizons, creating time and depth structure maps, and analyzing seismic. The four wells were correlated across two major sand bodies labeled as Sand A and Sand B. Five faults, designated F1 through F5, were selected based on amplitude distortion. In the 3D seismic volume, two horizons, designated Sand A and Sand B, were also identified with a similar wavelet nature. A NW-SE trending anticlinal structure supported by faults was delineated in the northern part of both reservoirs. Structural highs typically occur in the middle of the field for both reservoirs. For both reservoirs, structural lows may be seen in the northwest of the field. The western regions of both reservoirs are shown by high amplitudes on the RMS amplitude maps. Because Sand B occurs at a deeper depth than Sand A, Sand A has a higher concentration of low amplitudes than Sand B. The hydrocarbon-bearing structures are essentially based on the temporal and depth patterns of the mappable structures for the reservoir tops under examination, and they are mostly fault-dependent in nature. The detected structures and bright spots from seismic amplitude revealed that the Omicron field had good hydrocarbon potential.