Sensitivity analysis of technical and economic parameters for natural gas management in enhanced oil recovery projects

Abstract

Since oil reservoirs have different properties, each reservoir performs differently during enhanced oil recovery (EOR) processes. In some cases, water injection is the most effective method, while in others, gas injection or other methods will result in better performance. Most reservoir simulations assume that the amount of injection fluid is sufficient. However, in practice, the amount of available gas is enough to supply only a limited number of reservoirs. This study presents a comprehensive model which examines oil reservoirs in concert based on mathematical programming, and considers the competition between them. This model entails sensitive analysis of gas injection projects in order to determine effective factors (technical and economic parameters) on decision-making relating to gas injection projects. Results show that technical and economic parameters such as oil price, gas quality and gas price variation have a marked effect on economic results and may lead to favorable economic conditions. Variations were made in the model regarding changes in interest rate, number of wells and injection pressure, but these variations did not lead to unfavorable economic conditions; in other words, changes in these factors had no significant effect on stability.