RESERVOIR MODELLING AND SEAL INTEGRITY PREDICTION

Abstract

ABSTRACT Reservoir modelling and seal integrity prediction of ‘Sonia field,’ Onshore Niger Delta, vital for reservoir management are carried out in this work. The research utilized 3D seismic data and well logs to characterize the reservoirs and evaluate the sealing potential of the fault planes in the field. The methods employed include reservoir evaluation via the generation of facies, volume of shale, permeability, porosity and the 3D models, the fault seal analysis involves the computation of fault gouge parameters (Shale Smear Factor (SSF), Shale Gouge Ratio (SGR), Hydrocarbon Column Height (HCH), Fault Permeability and Fault Transmissibility). Four reservoirs were identified, the result of their petrophysical analysis shows porosity and permeability that are in the range of 0.27 - 0.30 and 5944 - 9000mD respectively, and are indicative of very good to excellent reservoir quality. The result of the SGR was validated with the SSF and their correlation shows SSF of 1 and 2.3 correspond to the SGR value of 25% and 24% respectively, indicating a continuous smear on the considered fault plane. The SGR therefore, suggests that the reservoirs mapped are dominantly in poorly sealing category with SGR values of 20 - 40%. The hydrocarbon column height for the faults ranges between 26.6 and 28 m, suggesting that the fault can only support a small column of hydrocarbon accumulation before leaking occurs. The predicted permeability model of the faults is less than 1mD in some regions along the fault plane with corresponding transmissibility values ranging between 0 and 0.20 revealing that these regions are potentially sealed with the consequence of preventing migration of fluid out of the reservoir. Based on the generated 3D models which indicate the distribution of the reservoir parameters, new hydrocarbon prospect locations are suggested for future drilling.