) Re-evaluation of A Compartmentalised Reservoir Leads To A Better Estimation of Oil in-Place (OIP): Etim Field Case Study

The Etim Field is located in OML-67 offshore southeastern Niger Delta on NNOC/MPN joint venture asset operated by Mobil Producing Nigeria. It was discovered in 1968 and had its first production in 1972. Thirty-three wells have been drilled to date on a stratigraphic-faulted anticlinal feature. Water depth in the field is 110 feet.The production performance of the Etim field Biafra reservoirs had indicated that its initial reserves estimate has been overproduced. Non-uniform pressure drop and irregular water movements characterized some of the early completions in the reservoir.Updated petrophysical evaluation has been calibrated to core and indicates net-to-gross ration and porosity range of 0.10-0.88 and 0.22-0.31 respectively. This suggests potential heterogeneity of the Biafra reservoir. RFT analysis also suggests the existence of barriers/baffles across the Biafra units and different oil-water contacts for individual units as opposed to a single contact for the whole formation.A new geologic framework was built integrating 3D seismic, core description and well data. Pressure and production performance data were also incorporated in an attempt to explain why cumulative production has exceeded initial estimated reserves.Results from this work suggest that the original oil in place (OIIP) was initially under-estimated and was at least twice the initial estimates.The field is now positioned for a redevelopment program based on the opportunities identified in this study. This will provide production uplift, eliminated or reduce water cut and optimize recovery