Three-Dimensional Reservoir Modelling of the Shallow Marine Sandstones in the Western Niger Delta

Accurate three-dimensional reservoir models integrating seismic and well data are essential for optimising sweep efficiency and recovery factor in mature Niger Delta producing fields, where remaining reserve exploitation increasingly depends on understanding intra-reservoir heterogeneity at fine scales. This study constructs a three-dimensional static reservoir model for a shallow marine sandstone interval within a field in the western Niger Delta, integrating wireline log petrophysics, core data, and interpreted three-dimensional seismic to characterise reservoir architecture. Sequential Gaussian simulation was employed to populate the model grid with porosity and permeability distributions consistent with histogram and variogram statistics derived from upscaled log data. Facies modelling preceded property simulation, using truncated Gaussian simulation constrained by interpreted seismic facies maps and a depositional environment model for a tide-influenced delta front setting. The model was validated against production history at five wells to assess predictive performance prior to scenario testing. Dynamic simulation runs using the static model as input examined the sensitivity of recovery factor to well spacing and water injection strategy. The study fills a research gap regarding the influence of barrier shales on vertical connectivity between sub-units within the Agbada Formation. Results provide field development planning guidance directly applicable to the operating company's infill drilling programme. Keywords: reservoir modelling, Niger Delta, sequential Gaussian simulation, petrophysics, intra-reservoir heterogeneity.