PETROPHYSICAL PROPERTY EVALUATION AND RESERVOIR CHARACTERIZATION IN THE B-FIELD, NIGER DELTA

Abstract

The Niger Delta Basin in southern Nigeria is a prolific hydrocarbon province characterized by complex structural and stratigraphic settings. This study aimed to characterize and evaluate reservoir intervals within the basin using an integrated approach combining well log analysis, seismic interpretation, and petrophysical assessments. Four reservoir intervals, labeled A-D, were identified through detailed well log analysis of gamma ray, resistivity, neutron, and density logs in four wells (B3 ST1, B10, B2, and B4) aligned in a southwest-northeast direction. Well log signature evaluation revealed a decrease in reservoir quality from the southwest (B10) towards the northeast (B3 ST1 and B4), as evidenced by diminishing electrical resistivity responses. This observation was corroborated by seismic mapping, which indicated a southward dip in the structural elevation of the reservoir beds. The updip/structurally higher positions were represented by B10 and B2, while B3 ST1 penetrated the downdip/structurally lower portion of the reservoirs. Seismic-to-well ties enabled the generation of structure maps for each reservoir top, facilitating the characterization of reservoir distribution and structural styles. Petrophysical assessments provided insights into key reservoir properties, including gross pay, net pay, porosity, and water saturation. The results suggest that the reservoirs have not reached their maximum potential and may involve both structural and stratigraphic trapping mechanisms due to lithological changes. This integrated approach has provided valuable insights into the reservoir characteristics and distribution within the Niger Delta Basin, which can inform future exploration and development strategies in the region.