Gas Lift Design and Analysis with WellFlo® Software
Using the program’s specialized capabilities for gas lift, engineers can design and model gas-lift installations and determine the number and position of the gas-lift valves, as well as the optimum injection rate taking account of the available injection pressure.
Gas-lift design section showing gas-lift valve spacing and valve calculations.
AGVM injection pressure sensitivity for an IPO valve.
Gas-lift design and diagnosis is a particular strength of the software making it (with its link to the only commercially available dynamic gas-lift simulator, Weatherford’s DynaLift™ program) a uniquely powerful gas-lift system. This is critical in a tool used for full gas-lift system modeling and optimization.
This program will allow you to incorporate gas injection rate or gas-liquid ratio terms as preferred. Together with the casing head pressure, these factors are input as sensitivity variables. For every rate specified, the program will determine which valve is being used for gas injection so that the system’s predictions are always accurate.
WellFlo features include the following modes of operation for analyzing and designing gas-lift systems:
- Continuous gas-lift design–deepest point of injection
- Gas-lift design–valve spacing for continuous and intermittent gas-lift installations
- Gas-lift design–valve sizing
- Gas-lift performance analysis–for continuous gas lift
- Advanced gas-lift valve modeling (AGVM)–for continuous gas lift, true valve performance
Advanced Gas-lift Valve Modeling
The pressures at which gas-lift valves allow gas to pass and the amounts of gas they pass depend upon the way they are constructed.
Orifice valves are simple: if there is sufficient pressure in the casing to reach the valve, then the major limitations on how much gas can be passed through the valve are the port size and the casing pressure.
Pressure controlled, or live, valves open at a pressure that is dependent upon overcoming a resisting force (bellows or spring). These mechanisms also allow the valve to be fully or partially open and to pass variable amounts of gas depending upon the balance of tubing and casing pressures and the valve port size.
The AGVM facility in the software introduces true valve performance into the computation of operating points.