The characterization of structural compartmentalization and bubble point pressure on production performance of the C−14 reservoir, OEM field, Niger Delta, Nigeria

This study presents an integrated reservoir performance analysis of the C−14 reservoir in the Niger Delta, aimed at optimizing production sustainability in a structurally complex, compartmentalized setting. Utilizing a data-conditioned workflow, the study integrates 3D seismic variance (coherence) attributes, well log interpretation, PVT modeling, and production history matching to construct an applicable geological framework. The reservoir is characterized by a growth-fault architecture, where consistent pressure offsets across fault blocks confirm a highly compartmentalized system. PVT analysis reveals a bubble point pressure of approximately 3,300 psia. Pressure decline below this threshold triggered two-phase flow, evidenced by rapid Gas-Oil Ratio (GOR) increases and elevated oil viscosity, which serve as proxies for depletion in data-sparse zones. A hierarchical weighting strategy was employed to manage variable data quality. High-confidence wells, specifically OEM−1 and OEM−3D, constrained depletion trends, while more volatile wells (e.g., OEM−8D, OEM−6D) served as secondary control points for testing spatial continuity. Over a 37-year production span (1979–2016), the field recovered 20.5 MMSTB. OEM−1 emerged as the primary contributor due to sustained pressure support, whereas wells like OEM−8D and OEM−4 suffered from early gas and water influx. Increasing water cuts post−1986 indicate progressive aquifer encroachment. This integrated approach provides a transferable framework for diagnosing fault-controlled dynamics and identifying redevelopment opportunities in mature deltaic reservoirs.