Gas lift

This article does not cite any references or sources. Please help improve this article by adding citations to reliable sources. Unverifiable material may be challenged and removed. (February 2008)

Gas lift is one of a number of processes used to artificially lift oil or water from wells where there is insufficient reservoir pressure to produce the well. The process involves injecting gas through the tubing-casing annulus. Injected gas aerates the fluid to reduce its density; the formation pressure is then able to lift the oil column and forces the fluid out of the wellbore. Gas may be injected continuously or intermittently, depending on the producing characteristics of the well and the arrangement of the gas-lift equipment.

Gas lift is a form of artificial lift where gas bubbles lift the oil from the well.

The amount of gas to be injected to maximize oil production varies based on well conditions and geometries. Too much or too little injected gas will result in less than maximum production. Generally, the optimal amount of injected gas is determined by well tests, where the rate of injection is varied and liquid production (oil and perhaps water) is measured.

Although the gas is recovered from the oil at a later separation stage, the process requires energy to drive a compressor in order to raise the pressure of the gas to a level where it can be re-injected.

The gas-lift mandrel is a device installed in the tubing string of a gas-lift well onto which or into which a gas-lift valve is fitted. There are two common types of mandrels. In a conventional gas-lift mandrel, a gas-lift valve is installed as the tubing is placed in the well. Thus, to replace or repair the valve, the tubing string must be pulled. In the side-pocket mandrel, however, the valve is installed and removed by wireline while the mandrel is still in the well, eliminating the need to pull the tubing to repair or replace the valve.

A gas-lift valve is a device installed on (or in) a gas-lift mandrel, which in turn is put on the tubing string of a gas-lift well. Tubing and casing pressures cause the valve to open and close, thus allowing gas to be injected into the fluid in the tubing to cause the fluid to rise to the surface. In the lexicon of the industry, gas-lift mandrels are said to be "tubing retrievable" wherein they are deployed and retrieved attached to the production tubing. See gas-lift mandrel.

Examples of typical gas-lift valves and mandrels may be found at: http://www.tejasre.com/Products_Gas_Lift_Home.cfm

Other typical examples of equipment also used in connection with gas-lift production may be found at: http://www.bstlift.com

See also

• Pumpjack
• Progressive cavity pump
• Submersible pump

v • d • e The petroleum industry Exploration Petroleum engineering (Reservoir simulation · Seismic to simulation) · Petroleum geology · Geophysics · Seismic (Seismic inversion) · Petrophysics · Core sampling Drilling Drilling engineering · Underbalanced drilling · Directional drilling · (Measurement while drilling · Geosteering) · Drilling fluid · Drill Stem Test Development Completion (Squeeze job) · Well logging · Pipeline transport · Tracers Production Artificial lift (Pumpjack · ESP · Gas lift) · EOR (Steam injection · Gas reinjection)  · Water injection · Well intervention · Upstream · Midstream · Downstream Technical challenges Differential sticking, Drilling fluid invasion, Blowouts, Lost circulation Oil and gas agreements Production sharing agreements, Concessions, Service Agreements, Risk agreements Data by country Total energy (consumption per capita · intensity) · Natural gas (consumption · production · reserves · imports · exports) · Petroleum (consumption · production · reserves · imports · exports) Supermajors ExxonMobil · Royal Dutch Shell · BP · Chevron Corporation · ConocoPhillips · Total S.A. (See also: National oil companies) Major oil provinces North Sea · East Texas · Persian Gulf · Athabasca oil sands · Gulf of Mexico · Venezuela · Niger Delta · Russia Related articles OPEC · Peak oil · Oil price increases since 2003 · Price of petroleum · Society of Petroleum Engineers