Gas Lift Valves - Tubing Retrievable

Valves whose opening and closing are controlled principally by casing (injection) gas pressure acting on a nitrogen-charged bellows or spring. They are the most common unloading valve type in continuous-flow gas lift and are set to close in sequence as injection gas reaches the operating point.

Valves controlled mainly by tubing (production) pressure, also called fluid-operated valves. They respond to changes in flowing tubing pressure and are used where production-pressure sensing gives more stable operation or in intermittent lift applications.

The deepest active valve in a continuous-flow design, sized and set to pass the steady injection gas rate at the planned point of injection. It establishes the operating gas-liquid ratio that sustains stable production.

Valves with larger ports and seats designed to dump a slug of gas quickly beneath a liquid column, then snap closed. They suit low-rate or depleted wells lifted in cyclic bursts rather than continuous flow.

Fixed-orifice devices, often with a reverse-flow check, that meter injection gas at the operating depth without pressure-actuated opening and closing. They provide a simple, predictable point of continuous injection.

Welded, full-bore mandrels that carry tubing-retrievable valves externally as part of the tubing string. The valve and mandrel are run and retrieved together with the tubing, distinguishing them from side-pocket wireline-retrievable systems.

Check assemblies that prevent backflow of tubing fluid into the casing annulus, and blank dummy valves used to seal a mandrel pocket or station that is not in service.