Geological Behavior (GBR)

This study integrates Lithostratigraphic descriptions, palynological analyses and gamma-ray wireline data from Uduak-1well at (340–3,510 ft) interval to characterize the lithofacies, establish palynostratigraphy and reconstruct depositional setting and paleoclimate of the Benin Formation in the Greater Ughelli depo-belt. Forty-three ditch-cutting samples were collected at ~60 ft intervals and were examined and combined with GR-log motifs and sand/shale ratios. Two principal lithofacies packages were identified: a sand-dominated continental unit (340–2,600 ft; sand:shale ≈ 98:2) and a continental–transitional unit (2,600–3,510 ft; ≈85:15). GR logs are generally low with intermittent peaks reflecting thin shaly interbeds/paleosols, while cylindrical and bell-shaped motifs indicate stacked channel and point-bar architectures. Palynological assemblages are dominated by freshwater-swamp taxa (e.g., Retitricolporites irregularis, Pachydermites diederixi) and Botryococcus, with only sporadic dinoflagellate occurrences near the base. Three palynozones/subzones (P624, P580, P560) were recognized and dated to the Rupelian–Chattian (Early–Late Oligocene), supporting a tentative Benin/Agbada boundary near ~3,490 ft. The sequence records a shift from marginal-marine/deltaic to fully continental, high-energy fluvial deposition under a warm, humid tropical climate. Integration of these data refines local biostratigraphy, improves lithofacies correlation for reservoir prediction, and enhances understanding of late Oligocene depositional dynamics in the onshore Niger Delta Basin.