Delineation of Depositional Sequences, Systems Tracts and Stratigraphic Model for Reservoir Prediction in Bilio-1 and Bilio-2 Oil Fields, Niger Delta, Nigeria

Abstract

The objective of this paper was to delineate the depositional sequences, systems tracts, and establish a reliable stratigraphic model for reservoir prediction in Bilio-1 and Bilio-2 oil fields, within Agbada Formation, Niger Delta Area, Nigeria using well log signature. Results identify a primary reservoir unit, designated as "B1000," characterized by an aggradational stacking pattern (3425–3400 SSTVD in BILIO-1 and 3410–3380 SSTVD in BILIO-2) indicative of stable-energy distributary channel fills. A regional maximum flooding surface (MFS) was precisely correlated at approximately 3375 SSTVD, marked by a prominent condensed section that serves as a field-wide chronostratigraphic marker. Electrofacies analysis reveals a transition from basal retrogradational transgressive phases to progradational shoreface sequences, reflecting the interplay between sediment supply and accommodation space. Correlation between wells confirms the lateral continuity of the reservoir sands, although structural shallowing is observed toward BILIO-2. This paper contributes a predictive model for hydrocarbon-bearing intervals, providing a robust geological basis for optimizing future development strategies in the Bilio Field.