Computational fluid dynamic (CFD) simulation of pilot operated intermittent gas lift valve

Abstract

To design an efficient intermittent gas-lift installation, reliable information is needed in the performance of all process components, from the outer boundary of the reservoir to the surface separators. The gas lift valve is the one critical component that affects the design of the whole system. In intermittent producing system, the pilot gas-lift valve is extremely used to control the point of compressed gas entry into the production tubing and acts as a pressure regulator. A novel approach using computational fluid dynamics simulation was performed in this study to develop a dynamic model for the gas passage performance of a 1-in., Nitrogen-charged, pilot gas-lift valve. Dynamic performance curves were obtained by using Methane as an injection gas with flow rates reaching up to 4.5 MMscf/day. This study investigates the effect of internal pressure, velocity and temperature distribution within the pilot valve that cannot be predicted in the experiments and mathematical models during the flow-performance studies. A general equation of the nonconstant discharge coefficient has been developed for 1-inch pilot valve to be used for further calculation in the industry without using CFD model. The developed model significantly reduces the complexity of the data required to calculate the discharge coefficient.

Keywords

• Gas lift
• Intermittent
• Pilot valve
• CFD
• Discharge coefficient