SEQUENCE STRATIGRAPHY OF WELL AE, NIGER DELTA SOUTHERN NIGERIA.

This study presents a detailed sequence stratigraphic and biostratigraphic interpretation of Well “AE”, located in the onshore Niger Delta, Southern Nigeria. The research integrates wireline log data and foraminiferal assemblages to establish a reliable depositional framework and age characterization for the studied interval. Lithologic analysis revealed alternating sandstone and shale units, representing typical deltaic sedimentation influenced by fluctuating sea levels. Twenty ditch cutting samples between 8,040 ft and 8,610 ft were processed and analyzed for foraminiferal content using standard micropaleontological procedures. The foraminiferal assemblages, comprising both benthic and planktonic species, were diverse and abundant enough to allow the delineation of six biostratigraphic zones. These include: Siphouvigerina ampullacea, Neogloboquadrina dutertrei, Haplophragmoides spp., Cristellaria spp., Lenticulina cultrata, and Valvulina flexilis zones. These zones correlate with the N7–N9 zones of the Blow et al. (1978) scheme, indicating an Early to Middle Miocene age for the studied sequence. The planktonic–benthic ratio and variations in species diversity were used to interpret the depositional environments, which ranged from middle neritic to upper bathyal settings. Sequence stratigraphic interpretation identified key surfaces, including a Maximum Flooding Surface (MFS) at approximately 8,400 ft (19.17 Ma) and a Sequence Boundary (SB) at about 8,460 ft (20.4 Ma). These surfaces correspond to major eustatic sea-level changes, helping define the Transgressive and Highstand Systems Tracts (TST and HST) within the well. The integration of biostratigraphy and wireline log data provided a clearer understanding of sedimentary processes, depositional history, and reservoir architecture.