Feasibility of Gas Lift to Increase Oil Production in an Iraqi Giant Oil Field

Abstract

Gas lift is one of the artificial lift techniques which it is frequently implemented to raise oil production. Conventionally, the oil wells produce depending on the energy of reservoir pressure and solution gas which declines due to continuous production. Therefore, many oil wells after a certain production time become unable to lift oil to the surface. Thus, the continuity of production requires implementation of gas lift which works to decrease the average fluid density in the tubing by injection gas through the annulus into the tubing. This paper aims to get maximum oil production of an Iraqi giant oil field at optimum injected gas rate. The field is located in south of Iraq and includes 67 wells. In this paper, new model is designed to matching PVT data, matching vertical pressure drop calculations, making sensitivity analysis of wellhead temperature variation, making sensitivity analysis of productivity index variation, achievement of optimum design of gas lift and finding optimum values of oil production and injected gas rate. The gas lift design is implemented within two cases. The first case aims to get the maximum oil production using flowing bottom hole pressure cut off as 50 psi above the bubble point pressure at certain depth. Whereas in the second plan, the same cut off value is maintained while keeping the injected gas oil ratio below or equals 350 SCF/STB. The two constraints are applied according to the policy of the operating company for the field under study. This results show the implementation of the gas lift technique can increase oil production from 64379 STB/D to 302712 STB/D in the first case and to 272359 STB/D in the second case. In addition, 45 ceased wells were brought to production by implementation of the gas lift. The model predicts that the required injected gas rates to produce the new production are 186.3 MMSCF/D and 74.606 MMSCF/D in the first and second cases respectively. The main conclusions lead to the application of gas lift technique for this reservoir can increase the oil production volume significantly.

Maximizing Production Profits: Optimizing Gas Lift Design in the Halfaya Oil Field

“…In an optimum scenario, it is desired to inject sufficient gas volume into individual wells to increase profitability. However, constraints related to gas availability can restrict the quantity of injected gas, indicating the importance of efficiently distributing gas within the gas lifting system [1,2]. For this purpose, a strategy of increasing the total oil production rate while instantaneously minimizing the amount of gas volume is required to sustain the system [3].…”

“…A Typical Gas-Lift Performance Curve [16] Many researchers have utilized various optimization approaches to enhance production from the Iraqi oil fields using the gas lift method. Al-Fatlawi et al conducted a study on a giant Iraqi oil field to determine the best design for gas lift operations [1]. They developed a new model that accurately matched PVT data, calculated tubing pressure drops, analyzed changes in the productivity index, analyzed variations in wellhead temperature, optimized gas lift design, and identified the best value for injected gas rate and oil production.…”

Optimization of Gas Lifting Design in Mishrif Formation of Halfaya Oil Field

“…Commonly, during the oil production process, oil naturally flows through the well-tubing. As a result of primary oil recovery, that includes a natural driving mechanism that lift oil from the perforation at the bottomhole to the well surface without the use of an artificial method [1,2]. However, in the majority of cases, primary oil recovery; oil production based on natural reservoir mechanism; won't commonly continue to flow naturally for a long period due to declining reservoir pressure [3,4].…”

“…In addition, there is a lot of hydrocarbons remaining in the oil reservoir, which is the reason for a common field problem. To produce the oil that still remains in the reservoir, it is necessary to consider future well/reservoir improvements, studies, and techniques, such as gas injection and water injection for secondary oil recovery or gas lift as an artificial lift technique [1,5]. Based on the status of the reservoir driving mechanisms, several artificial lift techniques are constructed which include electrical submersible pumps, hydraulic and sucker pumps, and gas lift technics, which can be utilized to lift the oil to surface production facilities [6][7][8].…”

“…If there is enough gas available, it is possible to apply the gas lift technique to decrease the required flowing bottomhole pressure to attain an economic flow rate. The most popular technique for activating wells is gas-lift [1,15]. The concept of gas lifting can be explained by the introduction of an external energy source, such as natural gas, through a casing-annular and into the tubing with the assistance of subsurface gas lifting valves.…”