The use of bellows is well known within the field of mechanical engineering. In that context, bellows are generally elastic vessels that are compressible and expandable when subjected to positive and negative pressures. These bellows are typically made of a suitable metal material and are designed to assume its original shape when the pressures are relieved. Metal bellows are typically made by forming, electroforming or by welding individual metal diaphragms to each other. Welded metal bellows are generally preferred for applications requiring high strength, precision, sensitivity and durability. The materials of welded bellows may be titanium, stainless steel or other high-strength, corrosion resistant, material.
Bellows, and particularly welded metal bellows, find may applications, such as mechanical seals and valves. For example, welded metal bellows are widely used in so-called gas lift valves that are installed in subterranean hydrocarbon wells.
Hydrocarbons, such as oil, gas and/or mixtures thereof, are normally found in subterranean reservoirs. These natural hydrocarbon reservoirs are exploited by drilling one or more boreholes (wells) into the reservoirs and extracting (producing) the hydrocarbons via suitable piping and process equipment. However, there are hydrocarbon reservoirs where the natural flow of hydrocarbons to the surface is not sufficient to allow or maintain profitable production of the well. This may, for example, be due to the viscosity and/or weight of the hydrocarbons, or that the pressure in the oil well is too low to counter the hydrostatic pressure of the fluid in the well as well as the counter-pressure that the processing installations on the surface exert on the fluid in the oil and/or gas well. The hydrocarbon reservoir may also, after being in production for some time, lose the pressure that is necessary to drive the hydrocarbons out of the reservoir.
Therefore, over the years, a number of systems and principles have been developed to increase the production of the well with the aid of artificial lifting. One common artificial lift method involves the use of injected gas. In such so-called gas lift method, a gas is injected at high pressure into the annular space between the casing and the production tubing. Pressure-controlled valves, so-called injection valves or gas lift valves, are used to supply and control the amount of gas that flows into the production tubing. The most common gas lift technique is that of continuous flow, which is very similar to natural flow. In continuous-flow gas lift systems, the gas emanating from the formation is supplemented with additional gas high-pressure, supplied from an external source. This external gas is injected continuously into the annulus and into the production tubing, and mixes with the produced well fluid. This process decreases the fluid density and the flowing pressure gradient of the mixture, and promotes fluid to flow into the wellbore. Gas lift valves may also be used during a start-up phase of a well, where completion fluid is found in both the well annulus and the production tubing. To start production in a well, completion fluid that is in the annulus must first be displaced, through one or more of the gas lift valves, and up to the surface through the production tubing.
The configuration and arrangement of these pressure-controlled valves will depend on a number of parameters. For example, depending on the size (diameter) of the production tubing and the injection pressure available, so-called gas injection points will be provided at one or more locations in and along the production tubing, the specific configuration for each individual well thus being adapted for optimal gas injection. The pressure-operated valve, e.g. a gas lift valve, will then be installed at these gas injection points, at the same or different locations along the longitudinal direction of the production tubing with the purpose of being able to initiate gas injection, such that through this artificial “lifting” an optimal production of the well is obtained.
The gas lift valve(s) may then be operated or controlled according to a number of different principles, for example, by means of pressure, where there are pressure differences around and/or across the valve that effect the control of the valve(s), i.e., the opening and closing of the valve.
The website www.prweb.com/releases/high_pressure/bellows_seal/prweb11869363.htm describes that Sensor Operations LLC Metal Bellows has developed a high pressure bellows seal for use in injection valve applications.
U.S. Pat. No. 6,932,581 B1 (Messick) discloses a gas lift valve usable with a subterranean well, and describes a housing, a valve stem and at least one bellows. The housing has a port that is in communication with a first fluid, and the valve stem is responsive to the first fluid to establish a predefined threshold to open the valve. The bellow(s) form a seal between the valve stem and the housing. The bellow(s) are subject to a force that is exerted by the first fluid; and a second fluid contained in the bellow(s) opposes the force that is exerted by the first fluid. The valve stem is comprised of a gas stem and a fluid stem, and the cross-sectional diameters of the gas and fluid stems are different. The gas stem and fluid stem may be separated parts that are coupled together by pressure during activation, or be manufactured as a single part.
U.S. Pat. No. 3,208,398 A (Douglas) describes a gas lift valve having a pressure chamber, an upper sealed bellows diaphragm suspended below the pressure chamber and being in fluid communication with therewith, and where the pressure chamber and bellows diaphragm are charged at a predetermined pressure above the atmospheric pressure. A valve assembly is attached below the upper bellows diaphragm and includes a sealed chamber, and a lower bellows diaphragm is suspended below the chamber and is in communication therewith. A valve head which is configured to interact with a valve seat is attached to the lower end of the lower bellows diaphragm.
WO 2008/150179 A1 (Tveiten, et al.) describes a valve device comprising an external structure with a longitudinal axis and a valve seat, and a valve body mounted movably inside the external structure. The valve device comprises a first bellows device permitted to be moved in a substantially radial direction, in fluid connection with a first fluid, and hydraulically connected to a second bellows device permitted to be moved in a substantially axial direction. The second bellows device is connected to a first part piston cooperating with a second part piston, thereby giving the second part piston an oppositely directed movement relative to the first part piston, which thereby moves the valve body relative to the valve seat.
U.S. Pat. No. 2,542,259 A (O'Leary) describes a valve having an expandable elastic bellows, cooperating with a valve member. U.S. Pat. No. 2,797,700 A (McGowen), U.S. Pat. No. 2,698,024 A (Canalizo), U.S. Pat. No. 2,610,644 A (Carlisle, et al.) describe flow valves utilizing bellows.
WO 2010/062187 A1 (Tveiten, et al.) describe a valve for use in an offshore or onshore oil and/or gas well for the purpose of increasing the production of the well. The valve comprises an outer structure in which a first and a second pressure-actuated bellows device are arranged, the first and second pressure-actuated bellows device, via a support means, being in fluid communication with each other. The support means is fixedly mounted internally in the outer structure, the support means thereby delimiting an open and a closed space for respectively the first and the second pressure-actuated bellows device, wherein the closed space is filled with a fluid under pressure, whilst the open space is in fluid communication with a surrounding fluid. Internally in the support means a movable piston is provided; the piston being allowed to be moved in the axial direction of the support means. The piston can further be configured such that, together with the through-hole in the top and/or bottom face of the support means, it forms a metal-to-metal seal, whereby when the piston is brought into contact with the top or bottom face of the support means, the first or the second pressure actuated bellows device will not be allowed a further movement in its axial direction.
U.S. Pat. No. 7,370,706 B2 (Becker, et al.) discloses a gas lift valve bellows assembly in which an internal piston incorporated within the bellows provides over travel prevention and over pressure protection during valve operation, independent of the set or operating gas pressures exerted on the gas lift valve. The piston separates a hydraulic damping reservoir in the interior convolutions of the bellows from the upper gas volume chamber. The piston travels a pre-set distance between two stops to provide a fluid dampened hydraulic balance across the bellows convolutions in both the open and closed positions of the valve.
U.S. Pat. No. 6,827,146 B2 (Faustinelli) discloses a double bellows gas lift valve to be seated in a gas lift pocket mandrel in an oil well. The valve comprises a casing with an adjustable choke installed in said oil well; a tubing within said casing, wherein a liquid slug may move from an oil reservoir to a surface of said oil well; an upper bellow having a stem operatively engaging a first seat and the upper bellow having a first pressure; and a lower bellow having a perforated lower stem operatively engaging a second seat and the lower bellow having a second pressure which is different than the first pressure of the upper bellow.
U.S. Pat. No. 8,701,779 B2 (Kleppa, et al.) discloses a valve device which is employed in connection with oil and gas wells with the object of increasing the well's production. The valve device comprises an external housing, where at least one inlet in the external housing is connected to an outlet through a longitudinal bore in the housing longitudinal direction. Between the valve device inlet and outlet a valve seat is mounted in the bore, where a valve body shuts off the connection between the inlet and the outlet. The valve body position is controlled by a support which is connected with a pressure-sensitive bellows device, comprising an upper and a lower bellows element. At a given external pressure, the lower bellows element in the bellows device will be compressed in the valve device axial direction, whereby this compression causes the two bellows elements' impact elements to be moved relative to each other, thereby causing the valve body to be lifted out of abutment with the valve.