| 摘要 |
A pilot operated gas lift valve utilizing a diaphragm formed of polymeric or elastomeric material and exposed to lift gas pressure on one side and atmospheric pressure on the other side, the diaphragm being able to withstand very high differential pressures and endure an extremely great number of operating cycles. The gas lift valve may be provided with an extension on the pilot valve member and this extension is exposed at all times to production fluid pressure, in which case, production fluid pressure will affect the operation of the gas lift valve. Thus, the gas lift valve may be 100 percent sensitive to production fluid pressure and totally insensitive to lift gas pressure, or its sensitivity to production fluid pressure may be as little as about four percent, depending upon the cross sectional area of the extension. Use of the diaphragm in the pilot valve mechanism provides essentially friction free operaton. Use of atmospheric pressure and a spring on the side of the diaphragm opposite the lift gas pressure avoids the effects of downhole temperatures on the pilot valve. Diaphragms formed of Teflon, especially virgin Teflon are disclosed should last for the life of most gas lift wells, and for operation in excess of 100,000 cycles. Also, diaphragms formed of elastomeric materials are also disclosed.
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