The aim of this study is to determine the impact of uncertainty in PVT properties on enhance oil recovery using CO2 Injection. A homogeneous 3D model using Eclipse 300 a compositional simulator was constructed with eleven components of hydrocarbon constituents present. The Peng –Robinson Equation of state (EOS) was used to characterize the fluids and the sensitivity study. The sensitivities were performed on the Binary interaction Coefficient, Fluid composition, miscibility, Temperature and Pressure of the reservoir system. The studies show that Fluid composition has a significant impact on the reservoir recovery factor .The miscibility effect sensitivity also shows that the recovery improves as the process becomes more miscible, while the sensitivity on the Binary interaction coefficient has no effect on the recovery factor of the reservoir ,also reservoir fluid composition with heavier hydrocarbons is unsuitable for CO2 enhanced oil recovery due to low API gravity. A 2D model sensitivity carried out on the temperature and pressure show that an increase in temperature gives an increase in the recovery based on the model, while a decrease in the reservoir pressure also has a significant increase in the reservoir recovery. The model result was linked to an economic model to determine the impact of uncertainty in PVT properties on the CO2 EOR to take economic decision based on economic indices such as NPV and IRR.

The management of oil and gas reservoirs is a dynamic process that require the cooperation of technical, operating, and management groups for the success of petroleum assets. It is a team that consists of robust seismic, geophysics, geology, petrophysical analysis, drilling, logging, geochemistry, reservoir engineering and reservoir management groups to mitigate the effects of uncertainties in reservoir characterization and flow processes via collection and analyses of key geologic, reservoir, and performance data through a logical application of multidisciplinary technologies. Thus, this paper presents a concise reservoir study workflow and challenges to assist new reservoir simulator users and a check for experts in this field with a detailed description of the activities involved in a complete reservoir simulation process from initialization, history matching to predictions. This was achieved by carefully considering the step by step process involved and the data required at each stage of the reservoir model building.