DEVELOPMENT OF A GAS CONDENSATE RESERVOIR

DEVELOPMENT OF A GAS CONDENSATE RESERVOIR

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.

Keywords: Gas condensate, reservoir modeling, reservoir development methods, NPV analysis,compositional fluid characterization

CHAPTER 1

1.0         INTRODUCTION

1.1         Problem Definition

The global demand for fossil energy is increasing immensely because of high population and development. With the unbundling of the power sector in Nigeria, and the fact that the country currently suffers from energy poverty complicated by low oil price or oil price volatility, oil companies are looking for ways to minimize costs and increase productivity.

Nigeria has an estimated 180 trillion standard cubic feet of natural gas proven reserves, making it ninth in the world, and the largest in Africa (World Factbook, 2014) with about a 50/50 distribution ratio between Non-Associated Gas (NAG) and Associated Gas (AG). The Natural gas available in Nigeria could either be associated or non-associated.

DEVELOPMENT OF A GAS CONDENSATE RESERVOIR