production · lift
Gas Lift Valve Pressure
click formula to derive ↑
Inputs
psi
psi
—
Description
Computes the casing (injection-gas) pressure required at depth to open a standard unbalanced, nitrogen-charged, injection-pressure-operated (IPO) gas lift valve, from the valve's dome charge pressure at depth temperature, the tubing (production) pressure acting on the port, and the valve's port/bellows area ratio. Used to check or set a valve's operating pressure against the well's actual injection-gas pressure at depth.
Variables
| Symbol | Unit | Description |
|---|---|---|
| Pvo | psi | Valve Opening Pressure (Injection/Casing Pressure at Depth) |
| Pd | psi | Nitrogen dome charge pressure already corrected to the valve's actual temperature at depth — not the 60°F test-rack reference pressure. This calculator does not perform that temperature correction; supply a value already corrected via a manufacturer chart or gas-lift design software (see limitations). |
| Pt | psi | Flowing production (tubing) pressure at the valve's setting depth. |
| R | — | Ratio of the valve's port area to its effective bellows area (Ap/Ab), from the valve manufacturer's specification — typically 0.05-0.20. |
Assumptions
- Valve is a standard unbalanced, single-element, nitrogen-charged, injection-pressure-operated (IPO) valve — the most common gas lift valve type
- Pd is supplied already corrected to the valve's actual well-depth temperature, not the 60°F test-rack reference pressure
- Spring force is neglected — this formula covers the pure nitrogen-charged-bellows case only
Limitations
- This calculator does not perform the nitrogen temperature correction from a 60°F test-rack charge pressure to actual valve-depth temperature. Two independently-checked industry sources describe that correction with opposite directional conventions for the correction factor Ct, and the primary source that would resolve it (Winkler & Eads, 1989, SPE-18871-MS) was not accessible during this calculator's citation-verification research. Supply Pd already temperature-corrected via a manufacturer's nitrogen chart or dedicated gas-lift design software — do not compute it from a naive ideal-gas temperature ratio, which is known to diverge meaningfully from real (compressed) nitrogen behavior at typical dome charge pressures.
- Neglects spring-loaded and fluid-operated (balanced) valve designs, which have different force-balance mechanics not covered by this formula.
- Neglects second-order dome-volume-change-with-stem-travel effects noted in the gas lift valve R-ratio literature — a known limitation of the constant-R assumption this formula makes.
- Does not account for the injection-gas throughput (flow capacity) the valve's port can actually pass at this pressure differential — that is a separate, distinct calculation (a Thornhill-Craver-type orifice flow equation), not covered here.
Use Cases
- → Valve setting design: Confirm a candidate valve's dome charge and R-factor will actually open at the intended casing pressure, given the expected tubing pressure at its setting depth.
- → Valve troubleshooting: Check whether a valve suspected of opening/closing at the wrong point in a gas lift string is behaving consistently with its as-charged dome pressure and R-factor.
Related Calculations
Region Notes
Permian Basin
Continuous-flow gas lift installations in the Permian typically use valves with R = 0.08-0.15 and dome charge pressures in the 800-1,400 psi range at depth, staged down a multi-valve string as part of an unloading sequence.
References
Primary source
Need geoscience support? BauerCalc is just one of the tools we build. If you're looking for independent expertise in well planning, geosteering, reservoir characterization, or opportunity evaluation, visit BauerSubsurface.com.