Stochastic Facies Architecture, Spatial Anisotropy, and Implications for Potential Reservoir Connectivity in a Heterogeneous Fluvio-Deltaic System, Onshore Niger Delta, Nigeria

Reservoir connectivity in fluvio-deltaic systems depends on the spatial arrangement of sand bodies and shale barriers. This study examines the potential static geological connectivity of the C2000–D1000 and D1000–D2000 intervals in the Chinak Field, onshore Niger Delta, using well logs, seismic interpretation, structural modelling, variogram analysis, and Sequential Indicator Simulation. The available modelled net-to-gross (NTG) ranges are 0.53882–0.95224 for C2000–D1000 and 0.47117463–0.99902231 for D1000–D2000. Fitted horizontal variogram ranges of 1,234 m and a vertical range of 3.9 m give a horizontal-to-vertical correlation-range ratio of approximately 316.4. The facies-model illustrations suggest potentially greater lateral sand-body continuity in C2000–D1000 and more channel-scale variability and possible compartmentalization in D1000–D2000. These are qualitative interpretations of potential static connectivity, not measurements of connected sand volumes or evidence of dynamic fluid communication. The absence of cell-level facies-grid exports prevented calculation of component counts, largest connected components, connected sand fractions, and uncertainty across realizations.