Integrated reservoir management in a Niger Delta oil rim field

Abstract

Several hundred million barrels of oil and trillions standard cubic feet of gas are enclosed within the oil rim reservoirs in the Niger Delta. The low recovery from these reservoirs can be attributed to the excessive early water and gas breakthrough at the wells which requires immediate attention. However, the majority of oil rims are thinly bedded and exist between strong aquifers and large gas caps which make preventing water and gas coning a very difficult task. The best approach to optimize production from these oil rims is effective reservoir management which involves evaluation, monitoring, goal setting, and revision of a few strategies for efficient field development. Current strategies to lessen these problems are limited due to their complexities and low recovery factor. This paper presents an integrated reservoir management approach for improved exploitation of an oil rim reservoirs in the Niger Delta. Seven development strategies were evaluated using Net-Present Value (NPV), Internal Rate of Return (IRR), and Discounted Payout Period (DPOP) criteria. In all these strategies, well placement, number of years of production, and production cycle were considered uncertain. The results show that well placement has a significant impact on efficient oil rims development. Therefore, by using a 1500 ft horizontal well, and a concurrent development strategy, maximum return on investment of 24.2% was achieved within a 3 years payout period. The framework developed in this present study is simple and reproducible and therefore recommended for oil rim development.