Numerical simulation of gas lift systems using the Volume of Fluid method

Resumo

Oil production in reservoirs declines over time as pressure decreases, presenting a challenge in maintaining economically desired production rates. Artificial lift methods can be used to address this issue, considering the characteristics of the production system, such as reservoir and fluid properties, as well as facility constraints. Gas lift involves injecting gas into lower sections of the tubing through strategically placed valves along the pipeline, effectively reducing the density of the fluid mixture and facilitating its upward flow. This lifting method is applicable to offshore operations and is not limited by well depth, allowing for different types of operations, including continuous or intermittent lift. In the present work, a gas lift flow is numerically studied using the volume of fluid method and a fluid mixture of water-air. The method is based on defining the liquid volume fraction and employing a transport equation to capture the interface. The interFoam solver from OpenFOAM-10 is used to simulate  a three-dimensional two-phase gas lift scenario. The setup consists of vertical water flow in a 44 mm pipe diameter, while air is injected through a 2 mm diameter orifice in the ortoghonal-flow direction. The total pressure drop is evaluated and compared with experimental data. The phase fraction and mean velocity profile are also obtained.