Gas lift valve with mixed bellows and floating constant volume fluid chamber
A valve apparatus capable of withstanding high pressures and techniques for using this apparatus in various suitable applications are provided. The valve apparatus typically includes both an upper bellows comprising a standard, convoluted bellows and a lower bellows comprising an edge-welded bellows. The valve apparatus may also include a floating, constant volume fluid chamber that travels with the lower edge-welded bellows as the lower bellows compresses and expands in an effort to protect the lower bellows from very high internal volume fluid pressure.
1. A valve for controlling fluid flow between an inlet and an outlet, comprising:
one or more components forming a housing for the valve;
a first bellows coupled to the housing;
a second bellows coupled to the housing, wherein the second bellows is a different bellows type than the first bellows;
a stem configured to move in the housing;
a shaft coupled to the housing, wherein the first bellows is coupled to the stem and to the shaft, such that compression of the first bellows causes the stem to move towards the shaft and expansion of the first bellows causes the stem to move away from the shaft; and
a sliding cylinder containing the first bellows, coupled to the stem, and configured to move along the shaft.
2. The valve of claim 1 , wherein the first bellows comprises an edge-welded bellows and wherein the second bellows comprises a convoluted bellows.
3. The valve of claim 1 , further comprising:
a seating element disposed in the housing, wherein an orifice in the seating element permits the fluid flow between the inlet and the outlet and wherein a sealing element associated with the stem is configured to mate with the orifice to prevent the fluid flow between the inlet and the outlet, thereby closing the valve.
4. The valve of claim 3 , wherein the second bellows is coupled to the housing and to a movable piston of a variable volume chamber in the housing and wherein the second bellows is compressed when the valve is closed.
5. The valve of claim 3 , wherein the first bellows is fully compressed to solid when the valve is open.
6. The valve of claim 3 , wherein the sealing element comprises a tungsten carbide (WC) ball disposed at a tip of the stem.
7. The valve of claim 3 , wherein the shaft is coupled to the housing at a first end of the shaft, wherein the first bellows is coupled to a second end of the shaft, and wherein the sliding cylinder is sealingly engaged to the second end of the shaft.
8. The valve of claim 7 , wherein a first volume between an inner diameter of the sliding cylinder and an outer diameter of the first bellows is filled with a first non-compressible fluid.
9. The valve of claim 8 , wherein the first non-compressible fluid comprises silicone oil.
10. The valve of claim 8 , wherein axial travel of the sliding cylinder relative to the shaft causes equal volumetric displacement of the first non-compressible fluid between an upper portion of the first volume above the second end of the shaft and a lower portion of the first volume below the second end of the shaft.
11. The valve of claim 8 , wherein a second volume formed by an inner diameter of the first bellows, an inner diameter of the second bellows, a duct of the shaft, and a hollow portion of the housing is filled with a second non-compressible fluid that is displaced as the first and second bellows are compressed or expanded.
12. The valve of claim 1 , wherein the valve is configured to operate in external pressures of at least 10,000 psi.
13. A method for performing downhole gas lift operations, comprising:
providing a valve comprising:
one or more components forming a housing having an inlet and an outlet for fluid flow;
a seating element disposed in the housing, wherein an orifice in the seating element permits fluid flow between the inlet and the outlet;
a stem configured to move in the housing, wherein a sealing element associated with the stem is configured to engage the orifice to prevent the fluid flow between the inlet and the outlet, thereby closing the valve;
a first bellows coupled to the housing and to the stem;
a second bellows coupled to the housing and to a movable piston of a variable volume chamber in the housing, wherein the second bellows is a different bellows type than the first bellows;
a shaft coupled to the housing, wherein the first bellows is coupled to the stem and to the shaft, such that compression of the first bellows causes the stem to move towards the shaft and expansion of the first bellows causes the stem to move away from the shaft; and
a sliding cylinder containing the first bellows, coupled to the stem, and configured to move along the shaft; and
opening the valve by injecting gas downhole, wherein an injected gas pressure is greater than a dome gas pressure in the variable volume chamber, such that the stem moves away from the seating element to allow the fluid flow between the inlet and the outlet via the orifice.
14. The method of claim 13 , further comprising closing the valve by discontinuing to inject the gas downhole, wherein the dome gas pressure is greater than an external gas pressure external to the housing such that the stem moves and the sealing element engages the orifice in the seating element.
15. The method of claim 13 , wherein the first bellows comprises an edge-welded bellows and wherein the second bellows comprises a convoluted bellows.
16. The method of claim 13 , wherein injecting the gas downhole fully compresses the first bellows to solid.
17. The method of claim 13 , wherein the shaft is coupled to the housing at a first end of the shaft, wherein the first bellows is coupled to a second end of the shaft, and wherein the sliding cylinder is sealingly engaged to the second end of the shaft.
18. The method of claim 17 , wherein a first volume between an inner diameter of the sliding cylinder and an outer diameter of the first bellows is filled with a first non-compressible fluid.
19. The method of claim 18 , wherein axial travel of the sliding cylinder relative to the shaft causes equal volumetric displacement of the first non-compressible fluid between an upper portion of the first volume above the second end of the shaft and a lower portion of the first volume below the second end of the shaft.
20. The method of claim 18 , wherein a second volume formed by an inner diameter of the first bellows, an inner diameter of the second bellows, a duct of the shaft, and a hollow portion of the housing is filled with a second non-compressible fluid that is displaced as the first and second bellows are compressed or expanded.