Development of a Gas Condensate Reservoir: Case Study of the Niger Delta

Abstract

Gas condensate reservoirs are single phase at the initial condition. It changes to multiphase when the reservoir conditions are located between the critical point and the cricondentherm of the reservoir in the phase envelope. This makes it unique to providing a reliable source of energy for human usage. The objective of this study is to use a 3D compositional model of the Niger Delta field to evaluate the production of a gas condensate reservoir. This study is integrated into two main segments; the reservoir and fluid pressure, volume and temperature (PVT) model followed by reservoir simulation studies. The simulation involves running several development scenarios using the 3D compositional model of the Niger Delta field to optimize the recovery from the reservoir of interest. Two vertical and horizontal wells were drilled in the model to study the production of the gas condensate reservoir using two development methods; natural depletion and gas cycling to maintain the reservoir pressure. Production of the gas condensate reservoir by maintaining a higher reservoir pressure through gas cycling maximized the hydrocarbon recovery. Economic analyses carried out on the net present value (NPV) of the various production methods studied in this work, revealed that gas cycling with vertical wells proved to be economical as a result of higher cash flow and the effect of injection cost on the project profitability. The results of this study gave further insights into the need to conduct detailed fluid PVT characterization and the importance of evaluating various reservoir optimization techniques in order to maximize recovery of oil from gas condensate reservoirs.