Gas Lift Valve Having Variable Orifice

Abstract

A gas lift valve includes a housing with an interior passage and first and second ports. The first port is exposed to either annulus pressure or tubing pressure, while the second port is exposed to the other. The interior passage has upper and lower shoulders on both sides of the first port. A pressure-sensitive piston is movably positioned in the housing, capable of axial movement in response to a pressure differential between the interior passage and a dome pressure. An indexing assembly includes a rotatable collar within the interior passage, between the upper and lower shoulders. The collar has an orifice port, an internal profile, and upper and lower edges. A biasing element pushes the collar toward the lower shoulder. A collet on the piston engages the collar's profile and moves the collar, which then rotates incrementally when the edges contact the respective shoulders.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Appl. No. 63 / 772,525 filed Mar. 15, 2023 and is filed concurrently with U.S. Non-Provisional application Ser. No. 19 / 089,232, entitled “Gas Lift Valve Having Ratcheting Orifice” (Atty. Dkt. No. 230-0854US), both of which are incorporated herein by reference in their entirety.BACKGROUND OF THE DISCLOSURE

[0002] To obtain hydrocarbon fluids from an earth formation, a wellbore is drilled into an area of interest within a formation. The wellbore may then be “completed” by inserting casing in the wellbore and setting the casing using cement. Alternatively, the wellbore may remain uncased as an (“open hole”), or it may be only partially cased. Regardless of the form of the wellbore, production tubing is run into the wellbore to convey production fluid (e.g., hydrocarbon fluid, which may also include water) to the surface.

[0003] Often, pressure within the wellbore is insufficient to cause the production fluid to naturally rise through the production tubing to the surface. In these cases, an artificial lift system can be used to carry the production fluid to the surface. One type of artificial lift system is a gas lift system, of which there are two primary types of systems: tubing-retrievable gas lift systems and wireline-retrievable gas lift systems. Each type of gas lift system uses several gas lift valves spaced along the production tubing. The gas lift valves allow gas to flow from the annulus into the production tubing so the gas can lift production fluid in the production tubing. Yet, the gas lift valves prevent fluid to flow in the opposite direction from the production tubing into the annulus.

[0004] A reverse arrangement can also be used for gas lift in which produced fluid travels up the annulus as annular flow (also referred to as revered flow). In this reverse arrangement, gas is injected into the tubing string, and the gas lift valves allow gas to flow from the tubing string to the annulus so the gas can lift production fluid in the annulus. Yet, the gas lift valves prevent fluid to flow in the opposite direction from the annulus to the tubing string.

[0005] A typical wireline-retrievable gas lift system 10 is shown in FIG. 1.

[0006] Operators inject compressed gas G into the annulus 22 between the tubing 20 and the casing 24 within a cased wellbore 26. A valve system 12 supplies the injection gas G from the surface and allows produced fluid to exit the gas lift system 10.

[0007] Side pocket mandrels 30 spaced along the production tubing 20 hold gas lift valves 40 within side pockets 32. As noted previously, the gas lift valves 40 are one-way valves that allow gas flow from the annulus 22 into the production tubing 20 and prevent reverse flow from the production tubing 20 into the annulus 22.

[0008] A production packer 14 located on the production tubing 20 forces the flow of production fluid P from a formation up through the production tubing 20 instead of up through the annulus 22. Additionally, the production packer 14 forces the gas flow from the annulus 22 into the production tubing 20 through the gas lift valves 40.

[0009] In operation, the production fluid P flows from the formation into the wellbore 26 through casing perforations 28 and then flows into the production tubing 20. When it is desired to lift the production fluid P, compressed gas G is introduced into the annulus 22, and the gas G enters from the annulus 22 through ports 34 in the mandrel's side pockets 32. Disposed inside the side pockets 32, the gas lift valves 40 control the flow of injected gas I into the production tubing 20. As the injected gas I rises to the surface, it helps to lift the production fluid P up the production tubing 20 to the surface.

[0010] Gas lift valves 40 have been used for many years to assist production of fluid to the surface. The gas lift valve 40 uses pressure-sensitive valve mechanism having a metal bellows and a piston to convert pressure into movement. Injected gas acts on the bellows to open the pressure-sensitive valve mechanism, and the gas passes through the gas lift valve 40 into the tubing string. As differential pressure is reduced on the bellows, the valve mechanism in the gas lift valve 40 can close.

[0011] Depending on the completion, other types of downhole devices may be installed in the side pocket mandrels 30. For example, “dummy” valves can be installed in the side pockets 32 of the mandrels 30 to allow for certain pressure tests to be performed. These dummy valves are not actually valves because they merely position in the mandrels 30 to seal of the mandrel's ports 34, acting as isolation devices.

[0012] With the dummy valves installed, for example, the integrity of the tubing and the casing of the completion can be tested at high pressures. After testing, the dummy valves are removed and replaced by live gas lift valves 40. Typically, wireline intervention is used to remove the dummy valves from the mandrels 30 and to then install the live gas lift valves 40 in the mandrels 30. The wireline intervention can be very time consuming, technically challenging, and expensive particularly in offshore applications.

[0013] The subject matter of the present disclosure is directed to overcoming, or at least reducing the effects of, one or more of the problems set forth above.SUMMARY OF THE DISCLOSURE

[0014] In one configuration of the present disclosure, a gas lift valve comprises a housing, a piston, and an indexing collar. The housing defines an interior passage having a first port and a second port. The first port is exposed to one of an annulus pressure and a tubing pressure, and the second port is exposed to the other of the annulus pressure and the tubing pressure. The piston is disposed in the housing and is biased by a dome pressure in the housing. The piston is movable in first and second axial directions with axial movement in the interior passage at least in response to a pressure differential between the dome pressure and an internal pressure in the interior passage. The indexing collar is disposed in the interior passage and defines an orifice port therein. The indexing collar is rotatably indexed in rotational positions in the interior passage in response to the axial movement of the piston in at least one of the first and second axial directions. Alignment of the orifice port with the first port is variable based on the rotational positions of the indexing collar.

[0015] In one arrangement, an indexing mechanism is arranged between the indexing collar and the interior passage. The indexing mechanism is configured to rotatably index the indexing collar in the rotational positions in the interior passage in response to the axial movement of the piston in the at least one of the first and second axial directions.

[0016] The indexing mechanism can comprise first and second shoulders and first and second edges. The first shoulder can be disposed in the interior passage and can define first castellations on one side of the first port. The second shoulder can be disposed in the interior passage and can define second castellations on an opposite side of the first port. The first edge of the inner collar can define first teeth; and the second edge of the inner collar can define second teeth. The first castellations can be ramped, and the first teeth can be ramped and can be configured to index in a first indexing engagement with the first castellations to rotate the indexing collar. The second castellations can also be ramped, and the second teeth can be ramped and can be configured to index in a second indexing engagement with the second castellations to rotate the indexing collar. The first teeth and the first castellations can match one another and can be smaller than the second teeth and the second castellations. Alternatively, the second teeth of the indexing collar can be configured to engage in a locking engagement with the second castellations.

[0017] In another arrangement, the indexing mechanism can comprise a slot profile and at least one pin. The slot profile can be defined on an outer surface of the indexing collar or on an inner surface of the interior passage, and the slot profile can have resting positions offset from one another. The at least one pin can extend from the outer surface or the inner surface and can be disposed in the slot profile.

[0018] The at least one pin can be configured to ride in the slot profile alternating between the resting positions.

[0019] In yet another arrangement, the indexing mechanism can comprise a slot profile and splines. The slot profile can be defined on one of an outer surface of the indexing collar or on an inner surface of the interior passage and can have cammed ridges. The splines can be defined on the other of the outer surface or the inner surface and can be disposed in the slot profile. The splines can have cammed ends alternating engaging between the cammed ridges.

[0020] In another configuration of the present disclosure, a gas lift valve comprises a housing, a piston, a collar, a collet, and an indexing arrangement. The housing defines an interior passage having a first port and a second port. The first port is exposed to one of an annulus pressure and a tubing pressure. and the second port is exposed to the other of the annulus pressure and the tubing pressure. The interior passage defines a first shoulder on one side of the first port and defines a second shoulder on an opposite side of the first port. The piston is disposed in the housing and is biased by a dome pressure in the housing. The piston is movable with axial movement in first and second axial directions in the interior passage at least in response to a pressure differential between the dome pressure and an internal pressure in the interior passage. The collar is disposed in the interior passage. The collar defines an internal profile and defines an orifice port therein. The collet is disposed on a distal end of the piston and is selectively engageable with the internal profile in the collar. The collet engaged with the internal profile of the collar is configured to move the collar with the axial movement at least in the first axial direction. The indexing arrangement is configured to rotate the collar in rotational positions in the interior passage at least in response to the collar is moved in the first axial direction. Alignment of the orifice port of the collar with the first port of the housing is variable with respect to the rotational positions of the collar.

[0021] In another configuration of the present disclosure, a method is used for a gas lift completion in a wellbore. The method comprises: producing pressure differentials in an interior passage of a gas lift valve between an annulus pressure of the wellbore and a tubing pressure of the gas lift completion; moving a piston in first and second axial directions in the gas lift valve in response to the pressure differentials; and indexing an alignment of an orifice port defined in an indexing collar in the gas lift valve with a first port in the gas lift valve. The step of indexing comprises: moving the indexing collar in the first axial direction with the piston engaged with the indexing collar and moved in the first axial direction; moving the indexing collar in the second axial direction; and rotating a rotational position of the indexing collar by an increment with at least one indexing engagement between the indexing collar and the interior passage in response to the indexing collar moved in at least one of the first and second axial directions.

[0022] The foregoing summary is not intended to summarize each potential embodiment or every aspect of the present disclosure.BRIEF DESCRIPTION OF DRAWINGS

[0023] FIG. 1 illustrates a conventional gas lift system.

[0024] FIG. 2A illustrates a gas lift mandrel with a gas lift valve of the present disclosure installed.

[0025] FIG. 2B illustrates a completion having gas lift valves according to the present disclosure.

[0026] FIGS. 3A-3B illustrate an elevational view and a cross-sectional view of a gas lift valve having an orifice varying assembly according to the present disclosure.

[0027] FIG. 4 illustrates a cross-section of the gas lift valve without features of a piston, bellows, and orifice varying assembly.

[0028] FIG. 5 illustrates a cross-section of the piston with its collet.

[0029] FIGS. 6A-6B illustrate a cross-sectional view and an elevational view of the movable collar of the orifice varying assembly relative to cam features of the housing.

[0030] FIG. 7 illustrates a cross-sectional view of a portion of the gas lift valve with the orifice varying assembly in an initial stage of operation.

[0031] FIG. 8 illustrates a cross-sectional view of the portion of the gas lift valve with the orifice varying assembly in a first stage of operation.

[0032] FIG. 9 illustrates a cross-sectional view of the portion of the gas lift valve with the orifice varying assembly in a second stage of operation.

[0033] FIG. 10 illustrates a cross-sectional view of the portion of the gas lift valve with the orifice varying assembly in a third stage of operation.

[0034] FIG. 11 illustrates a cross-sectional view of the portion of the gas lift valve with the orifice varying assembly in a fourth stage of operation.

[0035] FIG. 12 illustrates an elevational view of the side port on the gas lift valve in the fourth stage of operation.

[0036] FIGS. 13A-13B schematically illustrate another cam arrangement for the variable orifice assembly.

[0037] FIGS. 14A-14B schematically illustrate yet another cam arrangement for the variable orifice assembly.DETAILED DESCRIPTION OF THE DISCLOSURE

[0038] Referring to FIG. 2A, a gas lift mandrel 60 is installed on tubing 20 of a wellbore completion. The mandrel 60 is shown with a gas lift valve 100 of the present disclosure installed. As shown here, the gas lift valve 100 is wireline-retrievable, but the teachings of the present disclosure can apply to other types of valves, such as tubing-retrievable valves when used with an appropriate mandrel and tubing running procedures. The gas lift valve 100 includes a variable orifice assembly 150 according to the present disclosure. The variable orifice assembly 150 may be initially in a closed condition, but is configured to open once activated, as discussed later.

[0039] While the variable orifice assembly 150 is in the closed condition, the gas lift valve 100 can be run into the tubing 20 by wireline and can be inserted into the side pocket 65 of the mandrel 60. A latch 109 of the gas lift valve 100 engages a profile 69 in the side pocket 65 to hold the gas lift valve 100 therein. Packing seals 103a-b on the gas lift valve 100 isolate fluid communication between a port 66 on the mandrel 60 and the gas lift valve's side port 114 on the gas lift valve 100.

[0040] The gas lift valve 100 with the variable orifice assembly 150 can be an unloading-type of gas lift valve used for a typical tubing flow application. In this instance as will be described throughout the present disclosure, gas is injected down the annulus 22 in order to enter the tubing 20 through the mandrel 60 and the gas lift valve 100 so the injected gas can then lift production fluid up the tubing 20.

[0041] As an alternative, the gas lift valve 100 with the variable orifice assembly 150 can be used in an annular flow configuration in which gas is instead injected down the tubing 20 in order to enter the annulus 22 through the gas lift valve 100 and the mandrel 60 so the injected gas can then lift production fluid up the annulus 22. Although the annular flow configuration is less common, it is applied in certain circumstances. To achieve the annular flow configuration, features, and operation of the gas lift valve 100 and the variable orifice assembly 150 are essentially reversed, and a different form of gas lift mandrel may be used. In general, one port of the gas lift valve 100 is exposed to the tubing 20, while another port of the gas lift valve 100 is exposed to the annulus 22. The variable orifice assembly 150 operates with the pressure differential between the ports to configure the active opening of the gas lift valve 100. In this reverse arrangement, produced fluid travels up the annulus as annular flow (also referred to as revered flow). Gas is injected into the tubing string, and the gas lift valve 100 allows gas to flow from the tubing string to the annulus so the gas can lift production fluid in the annulus. Yet, the gas lift valve 100 prevents fluid to flow in the opposite direction from the annulus to the tubing string.

[0042] Instead of being conventional, the gas lift valve 100 is configured to be selectively vary the flow that can pass through the gas lift valve 100 during operation. For example, the variable orifice assembly 150 can keep the gas lift valve 100 closed so pressure testing can be performed. For pressuring testing, the tubing pressure TP can be increased in the tubing 20 to test the tubing's integrity. Alternatively, the annulus pressure TP can be increased to test the casing's integrity.

[0043] The gas lift valve 100 can also be opened when ready to inject gas through the side pocket mandrel 60 and the gas lift valve 100 for entry into the tubing 20 of the completion string. In particular, using different predetermined pressure differentials the gas lift valve 100 is configured to vary the opening and closing between the annulus pressure and the tubing pressure so the gas lift valve 100 can be used for gas injection. In this way, wireline intervention to remove a dummy valve and replace it with a live gas lift valve is not needed to test the completion's integrity as required in conventional practice. Also, workover is not needed to switch out the gas lift valve 100 for another vale with a different flow setting or to alter the gas lift valve to provide a different flow setting.

[0044] To vary the opening and closing of fluid communication, the gas lift valve 100 includes the variable orifice assembly 150, details of which are discussed later.

[0045] An example completion assembly 50 is shown in FIG. 2B having multiple gas lift valves 100 installed on tubing 20 disposed in casing 24 of a wellbore. Each of the gas lift valves 100 is installed in a gas lift mandrel 60 on the tubing 20, and each of the valves 100 has a variable orifice assembly 150 to vary the flow setting of the gas lift valve 100.

[0046] The multiple gas lift valves 100 can be used together with a shear orifice valve 70 installed at the deepest point in the completion assembly 50. The shearable orifice valve 70 has a shear open mechanism set to open at a higher pressure than the activation pressure for the variable orifice assembly 150 on the gas lift valves 100. An example of such a shearable orifice valve 70 is the “RDDK-2A Shearable Orifice Gas-Lift Valve” available from Weatherford International, Inc.

[0047] The variable orifice assemblies 150 allow the casing 24, the tubing 20, and other components (e.g., packers) in the well completion assembly 50 to be tested. Then, the gas lift valves 100 can be varied open and closed with a variable orifice. The variable orifice assemblies 150 allow gas lift operations to proceed without wireline intervention.

[0048] In one configuration, the variable orifice assemblies 150 of the gas lift valves 100 are activated in response to a predetermined pressure differential between the annulus pressure AP and the tubing pressure TP (i.e., the annulus pressure AP in the annulus 22 increased a predetermined level above the tubing pressure TP). As used herein, “annulus pressure” AP refers to the pressure in the annulus 22 between the tubing 20 and the casing 24. By contrast, “tubing pressure” TP refers to the pressure in the tubing 20 of the completion string in the wellbore.

[0049] For example, the tubing 20 and the annulus 22 are filled with completion fluid, which creates hydro-static pressure on each inlet and outlet side of the ports 112, 114 of the gas lift valves 100. With communication through the ports 112, 114 closed, operators can first perform a tubing test by increasing the tubing pressure TP to a set test pressure. This tests the integrity of the tubing 20 of the completion string. The operators then bleed off the tubing pressure TP.

[0050] At this point, operators increase the annulus pressure AP to apply a set test pressure to the annulus 22 from the surface. This increase in annulus pressure AP can test packers (not shown) and the casing 24 of the completion assembly 50 by creating a pressure differential between the casing 24 and the tubing 20.

[0051] With the casing's integrity tested, the annulus pressure AP is then increased to a first predetermined level above the set test pressure to open the variable orifice assemblies 150 of the gas lift valves 100. The annulus pressure AP can then be increased even further to a second, higher predetermined level to open the shearable orifice valve 70.

[0052] Once the annulus pressure AP reaches the opening pressure differential of the shearable orifice valve 70, the annulus and tubing pressures AP, TP throughout the wellbore will equalize. With the pressures AP, TP then equalized, the gas lift valves 100a-c are now in open conditions and ready for gas injection operations.

[0053] The variable orifice assemblies 150 of the gas lift valves 100 can be configured to open after testing in response to increased tubing pressure TP. (This installation may not use the shearable orifice valve 70 on the completion assembly 50.) During testing, for example, the tubing 20 and the annulus 22 are filled with completion fluid, which creates hydro-static pressure on each side of the gas lift valves 100. Operators first perform a casing integrity test by increasing the annulus pressure AP from the surface to a set test pressure. This increase in annulus pressure AP tests any packers and tests the casing 24 of the completion assembly 50 by creating a pressure differential in the annulus 22 relative to the tubing 20. The annulus pressure AP is then bled off.

[0054] Operators then increase the tubing pressure TP to a predetermined level that opens the variable orifice assemblies 150 of the gas lift valves 100. Although the gas lift valves 100 are now open, certain check valves (e.g., check valve 140 in FIG. 3A) in the gas lift valves 100 will close and prevent reverse flow of pressure from the tubing 20 to the annulus 22. The operators can now test the tubing integrity by increasing the tubing pressure TP to a set test level. The tubing pressure TP is then bled off, and the gas lift valves 100a-c are now in open conditions and ready for gas injection.

[0055] After testing, the amount of flow that can pass through the gas lift valves 100 can then be varied by cycling the pressure differentials between the annulus pressure AP and the tubing pressure TP. The cycling varies the available orifice for flow through the gas lift valves 100 in a manner discussed in more detail below.

[0056] Having an understanding of how an variable orifice assembly 150 of the present disclosure is used on a gas lift valve 100 in a completion assembly 50, discussion now turns to particular details of the different configurations of the variable orifice assembly 150.

[0057] FIGS. 3A-3B illustrate an elevational view and a cross-sectional view of a gas lift valve 100 having a variable orifice assembly 150 according to the present disclosure. As shown, the gas lift valve 100 is an unloading-type of gas lift valve, and the variable orifice assembly 150 is configured to open and close the gas lift valve 100 in response to pressure differentials between the annulus pressure AP and the tubing pressure TP.

[0058] The gas lift valve 100 can be configured as a tubing-conveyed valve or can be a wireline retrievable valve. In the configuration shown in FIG. 3A, for example, the gas lift valve 100 is wireline retrievable and can be removable from and (installable in) a side pocket of a side pocket mandrel (60) while the production tubing string remains downhole within the wellbore. A kickover tool (not shown) or other known deployment tool can be used to retrieve and install the gas lift valve 100. Any suitable latch 109 known in the art can be used for deploying the gas lift valve 100 in a side pocket mandrel (60). In general, the latch 109 threads to the tail piece 105 of the gas lift valve 100. A latching profile can be engaged by the retrieving tool. A frangible member, such as a shear pin, disposed of on the body, releasably connects the latch mechanism within a latch recess area. A spring on the latch body is biased against a latch ring abutted against a latch stop. The latch ring and latch stop cooperate to provide means for connecting the latching mechanism within the latch recess area to anchor the gas lift valve 100 within a side pocket.

[0059] The gas lift valve 100 has a housing 101, a piston 130, and a variable orifice assembly 150. The housing 101, which is shown in cross-section with some internal components missing, defines an interior flow passage 110 therein and has an end port 112 and a side port 114. In one configuration, the end port 112 can be an outlet exposed to tubing pressure TP of the tubing, while the side port 114 can be an inlet exposed to the annulus pressure AP. A reverse arrangement of exposure can be used.

[0060] For ease of assembly, the housing 101 can be composed of several housing components connected together. For example, the housing components can include an end port housing 102, a side port housing 104, a bellows adapter 106, a dome housing 108, and a tail piece 105. The end port housing 102 has the end port 112 communicating with interior flow passage 110, and the side port housing 104 has the side port 114 communicating with the interior flow passage 110. A tail plug 107 and a core valve 122 on the tail piece 105 holds a dome pressure in a dome chamber 120 of the gas lift valve 100. Typically, the dome chamber 120 can hold a compressed gas, typically nitrogen, which is filled through the core valve 122 in the tail piece 105.

[0061] The housing 101 has annular seal 103a-b, such as packing stacks, disposed about the housing 101 on both sides of the side port 114. In this way, the annular seals 103a-b seals the side port 114 from the end port 112 and isolates the annulus pressure AP and the tubing pressure TP when installed in a typical side-pocket gas lift mandrel (e.g., 60; FIG. 2A). Accordingly, the gas lift valve 100 run into the mandrel (60) is exposed to annular pressure AP through the side port 114 communicating with the mandrel's injection ports (66), and the end port 112 is exposed to tubing pressure TP. Thus, the term “annular pressure” used in reference to the gas lift valve 100 refers to the pressure in the wellbore annulus at the side port 114 of the gas lift valve 100, whereas the term “tubing pressure” refers to the pressure in the completion string at the end port 112 of the gas lift valve 100.

[0062] Internally, the gas lift valve 100 uses a pressure-sensitive mechanism to control gas injection. In particular, a piston 130 disposed in the housing 101 includes a bellows 135 connected between the piston 130 and the interior flow passage 110. The gas lift valve 100 uses this bellows 135 as a membrane that separates the dome chamber 120 from the interior flow passage 110 exposed to the end port 112 and the side port 114. The dome chamber 120 and the bellows 135 bias movement the piston 130, and the piston 130 is movable in the gas lift valve 100 in response to pressure differential across the bellows 135.

[0063] A collet 132 on the piston 130 interacts with the variable orifice assembly 150 discussed in more detail below. (FIG. 5 shows an isolation view of the piston 130 and collet 132 in cross-section.) The interaction of the collet 132 with the variable orifice assembly 150 can alter how much flow of injected gas entering from the side port 114 can pass through the interior flow passage 110 to the housing's end port 112 (or vice versa depending on the installation).

[0064] To prevent reverse flow from the tubing to the annulus through the gas lift valve 100, a check valve 140 can be used in the interior flow passage 110 of the gas lift valve 100. As is typical, the check valve 140 can be a dart valve with ports and can have a spring that biases the check valve 140 toward a seat.

[0065] Rather than having a conventional inlet and outlet for passage of injected gas directly out of the gas lift valve 100 from the interior flow passage 110 to a completion string (not shown), the gas lift valve 100 of FIGS. 3A-3B includes the variable orifice assembly 150 installed at the side port 114 for controlling fluid communication with the interior flow passage 110. This variable orifice assembly 150 can vary the amount of fluid communication through the gas lift valve 100 in a manner described latter.

[0066] In general, the variable orifice assembly 150 includes an indexing collar 160 disposed in the interior flow passage 110. The indexing collar 160 has a bore 162 and defines one or more orifice ports 164 (one shown) therein. (FIGS. 6A-6B show an isolated, cross-sectional view and an isolated, elevational view of the indexing collar 160 relative to cam features of the housing (101). Briefly, the indexing collar 160 has first and second (upper and lower) edges or intermediate cams 165a-b, which are illustrated relative to first and second (upper and lower) shoulders or cams 115a-b defined in the interior flow passage (110) of the housing (101). In this arrangement, the intermediate cams 165a-b include ramped teeth 167a-b, and the housing's cams 115a-b include ramped castellations or teeth 117a-b.)

[0067] During operation, the indexing collar 160 is rotatably indexed in rotational positions in the interior flow passage 110 in response to the axial movement of the pressure-sensitive piston 130 in at least one of the first and second axial directions. Alignment of the orifice port 164 with the first port 114 is variable with respect to the rotational positions of the indexing collar 160.

[0068] In particular, the piston 130, being sensitive to the pressure, is movable with axial movement in a first (upward) direction in the interior flow passage 110 in response to a first pressure differential between the first and second ports 112 and 114. The collet 132 of the piston 130 is selectively engageable inside the collar's bore 162, and the indexing collar 160 is movable with the axial movement by the pressure-sensitive piston 130 engaged with the indexing collar 160. As noted, for example, the piston 130 includes the collet 132 disposed on a distal end of the piston 130. The collet132 is selectively engageable with an internal profile 166 of the indexing collar 160. In this way, the indexing collar 160 is movable in the first (upward) direction by the collet 132 engaged with an internal profile 166 of the indexing collar 160. The indexing collar 160 moved in the first (upward) direction is rotatable in an increment of the rotational positions in response to an indexing engagement (115a, 165a) between the indexing collar 160 and the interior flow passage 110.

[0069] The engagement of the collet 132 with the profile 166 can permit the incremental rotation of the indexing collar 160 when it is indexed. The collet 132 includes fingers 134 separated by flexing slots, and the fingers 134 have keys 136, which can engage in the internal profile 166.

[0070] In turn, a biasing element 168, such as a collar spring, biases the indexing collar 160 in a second (downward) direction in the interior flow passage 110. Biased by the collar spring 168, the indexing collar 160 is also movable in the second (downward) direction in response to the collet 132 of the piston 130 being disengaged with the indexing collar 160. The indexing collar 160 moved in the (downward) direction is at least fixable in the given rotational position in response to a locking engagement (115b, 165b) between the indexing collar 160 and the interior flow passage 110. Moreover, the indexing collar 160 moved with the second direction can be rotatable in another increment of the rotational positions in response to an indexing engagement (115b, 165b) between the indexing collar 160 and the interior flow passage 110.

[0071] In one configuration for the indexing engagement (115a, 165a), the interior flow passage 110 defines a first (upper) shoulder 115a on a first (upper) side of the side port 114, and the indexing collar 160 defines a first (upper) edge 165a. The upper shoulder 115a and the upper edge 165a can be ramped or cammed. In particular and as also shown in FIGS. 6A-6B, the upper edge 165a can include a plurality of ramped teeth (167a) disposed circumferentially about the upper end of the indexing collar 160, and the upper shoulder 115a can include a plurality of ramped castellations (117a) disposed circumferentially thereabout. As the ramped teeth (167a) engage the ramped castellations (117a), the offset of the ramped teeth (167a) and castellations (117a) can cause the indexing collar 160 to rotate an increment, which varies the alignment of the orifice port 164 with the side port 114.

[0072] During operation, the piston 130 can be moved with the second axial movement in the interior flow passage 110 in response to a second pressure differential in the gas lift valve 100 opposite to the first pressure differential. The indexing collar 160 can remain fixed in the given rotational position with the locking engagement regardless of the pressure-sensitive piston 130 being engaged in the second axial movement with the indexing collar 160.

[0073] In one configuration, the locking engagement (115b, 165b) can also use an indexing engagement to produce an increment in the rotational position. Accordingly, the interior flow passage 110 defines a second (lower) shoulder 115b on a second (lower) side of the side port 114, and the indexing collar 160 defines a second (lower) edge 165b. The lower shoulder 115b and the edge 165b can be ramped or cammed. In particular and as also shown in FIGS. 6A-6B, the lower edge 165b can include a plurality of ramped teeth (167b) disposed circumferentially thereabout, and the lower shoulder 115b can include a plurality of ramped castellations (117b) disposed circumferentially thereabout. As the ramped teeth (167b) engage with the ramped castellations (117b), offset of the ramped teeth (167b) and castellations (117b) may cause the indexing collar 160 to rotate a further increment, which varies the alignment of the orifice port 164 with the side port 114. Preferably, the ramped teeth (167a) and castellations (117a) of the upper edge 165a and the upper shoulder 115a are smaller than the ramped teeth (167b) and castellations (117b) of the lower edge 165b and the lower shoulder 115b, which can enhance the offset used to rotate the indexing collar 160.

[0074] Alternatively, the incremental rotation of the indexing collar 160 can be achieved exclusively with the upper engagement (115a, 165a), and the lower teeth and castellations may not be ramped or cammed, may not have any offset, and may merely align to engage one another. The reverse is also possible in which the incremental rotational can be achieved exclusively with the lower engagement (115b, 165b).

[0075] Other configurations can be used for the indexing and locking engagement of the indexing collar 160. In one example discussed below with reference to FIGS. 13A-13B, a pin and slot arrangement can be used between the indexing collar 160 and the interior flow passage 110 of the housing 101. The indexing collar 160 can include a profiled slot, which can ride along one or more pins extending in the side of the housing 101 into the interior flow passage 110. As the indexing collar 160 is reciprocated, movement of the profiled slot along the pin can produce the incremental rotation of the indexing collar 160 to vary the alignment between the orifice port 164 and the side port 114.

[0076] In another example discussed below with reference to FIGS. 14A-14B, a profiled slot can be defined on the outside of the indexing collar 160 and can be engaged with complementary cammed ribs defined on the inside surface of the passage. As the indexing collar 160 is reciprocated, engagement between the cammed ribs and profiled slot produce the incremental rotation of the indexing collar 160 and vary the alignment between the orifice port 164 and the side port 114. These and other indexing arrangements can be used.

[0077] FIG. 7 illustrates a cross-sectional view of a portion of the disclosed gas lift valve 100 with the variable orifice assembly 150 in an initial stage of operation. No load has been applied to the pressure-sensitive piston (130) by a pressure differential. As can be seen, the orifice port 164 of the indexing collar 160 is misaligned with the side port 114 of the housing 101 so that a reduced or choked flow condition can be achieved. As generally shown, the orifice port 164 can include a tapered, cutout, teardrop, or another non-circular shape so that variations in flow can be achieved. Other configurations can be used. For example, the indexing collar 160 may include various smaller orifice ports 164 that can be consecutively aligned with a larger side port 114 to vary the orifice area for fluid communication.

[0078] Although not explicitly shown, sliding seals can be used between the indexing collar 160 and the interior flow passage 110 to seal off communication of the orifice port 164 with the side port 114. Because the orifice port 164 would still be radially exposed to the side port 114 if only circumferential seals (e.g., radial O-ring seals) were used, other forms of sealed isolation could be used if desired.

[0079] During operations, the first pressure differential is produced in the interior flow passage 110 of the gas lift valve 100 between annulus pressure AP of the wellbore and tubing pressure TP of the gas lift completion. For example, FIG. 8 illustrates a cross-sectional view of the portion of the disclosed gas lift valve 100 with the variable orifice assembly 150 in a first stage of operation. The application of pressure has begun, producing a greater pressure in the interior flow passage 110 compared to the charge pressure in the dome chamber (120). In response to the first pressure differential, the piston 130 is subject to the first pressure differential across the bellows (135) separating the charge pressure in the dome chamber (120) from the pressure present in the interior flow passage 110. The piston 130 starts to move with a first (upward) movement in the gas lift valve 100 in response to the first pressure differential. As can be seen, the lower ramped teeth 167b lose contact with the lower ramped constellations 117b as the piston (130 moves the collet 132 upward and starts to shift the indexing collar 160 upward.

[0080] Pressure can be communicated into the interior flow passage 110 either from annulus pressure or tubing pressure via the ports 112, 114. Because some fluid communication can be achieved between the side port 114 and orifice port 164 and can bypass the misalignment of the indexing collar 160, annulus pressure from the side port 114 can still enter the interior flow passage 110 to produce the desired pressure differential.

[0081] FIG. 9 illustrates a cross-sectional view of the portion of the disclosed gas lift valve 100 with the variable orifice assembly 150 in a second stage of operation.

[0082] The continued application of pressure in the interior flow passage 110 has moved the pressure-sensitive piston 130 and collet 132 further upward, shifting the indexing collar 160 so that the upper teeth 167a engage with the upper castellations 117a. An alignment of the orifice port 164 defined in the indexing collar 160 is thereby varied relative to the side port 114 as the piston 130 engages with the indexing collar 160, as the indexing collar 160 then moves with the first (upward) movement, and the rotational position of the indexing collar 160 is incremented by the indexing engagement between the indexing collar 160 and the interior flow passage 110.

[0083] FIG. 10 illustrates a cross-sectional view of the portion of the disclosed gas lift valve 100 with the variable orifice assembly 150 in a third stage of operation. The continued application of pressure causes the collet's fingers 134 to collapse so the keys 136 start to release from the profile 166 of the indexing collar 160. The collar spring 168 can then push the indexing collar 160 in the downward direction as the collet 132 loses its engagement with the indexing collar 160.

[0084] FIG. 11 illustrates a cross-sectional view of the portion of the disclosed gas lift valve 100 with the variable orifice assembly 150 in a fourth stage of operation.

[0085] The continued application of pressure has caused the collet's keys 136 to be released completely from the profile 166 of the indexing collar 160. The biasing force of the collar spring 168 forces the indexing collar 160 downward so that the lower teeth 167b engage the lower castellations 117b. This produces an additional rotation of the indexing collar 160, varying the rotational position of the orifice port 164 to the side port 114. The indexing collar 160 is now fixed in the given rotational position with the locking engagement between the indexing collar 160 and the interior flow passage 110.

[0086] When the application pressure is reduced, a reverse pressure differential can result in the charge pressure in the dome chamber 120 being greater than the pressure in the interior flow passage 110. The piston 130 can move downward. The collet 132 can collapse and re-enter inside the bore 162 of the indexing collar 160 so that the gas lift valve 100 is reset. Even with the re-entry of the collet 132, the existing alignment between the orifice port 164 and the side port 114 can be maintained because the downward movement of the collet 132 against the indexing collar 160 will not rotate the indexing collar 160, which remains fixed by the locking engagement between the ramped teeth and castellations 117b, 167b.

[0087] As can be seen in FIG. 12, the incremented rotation of the indexing collar 160 has exposed a portion of the orifice port 164 with the gas lift valve's side port 114. Repeated applications and releases of pressure as discussed above can rotate the indexing collar 160. Different alignments can be achieved between the orifice port 164 of the side port 114. The different alignments can vary the available orifice area through which fluid (e.g., injected gas) can communicate.

[0088] The variable orifice assembly 150 allows the orifice size to be changed in the gas lift valve 100 without needing workover. The variable orifice assembly 150 allows a new orifice size to be utilized each time an operator reduces and reapplies casing pressure during gas injection. The variable orifice assembly 150 uses the collet 132 attached to the piston 130, which is bellows-biased and pressure sensitive, to grab and release the indexing collar 160 when casing pressure is reduced and then reapplied. The indexing collar 160 rotates to either allow or interfere with the side port 114 to change the orifice size.

[0089] The fingers 134 of the collet 132 will travel with the application and reduction of the casing pressure to grab and release the indexing collar 160, which is biased with the collar spring 168. The indexing collar 160 can have a teardrop shaped opening that interfaces with the housing's side port 114 allowing communication between annulus and tubing. The indexing collar 160 also contains teeth 167a-b on each end that interacts with castellations 117a-b on the housing 101, which are out of phase with each other. When the collet's fingers 134 grab the indexing collar 160, the indexing collar 160 is rotated when it begins interacting with the housing castellations 117a-b. With continued casing pressure, the collet 132 eventually releases the indexing collar 160, which is then biased to the lower castellations 117a on the other end of the housing 101 by the collar spring 168. This causes further rotation of the indexing collar 160. The repetition of the casing pressure cycle causes the indexing collar 160 to continue rotation that changes the amount of orifice port 164 is exposed to the housing's side port 114, changing the flow area (or orifice size) of the variable orifice assembly 150.

[0090] As noted above, the variable orifice assembly 150 can use cams to produce the indexed rotation of the indexing collar 160 that changes the alignment of the orifice port 164 and the side port 114. For example, the offset teeth and castellations disclosed above is one of several mechanisms to index or rotate the inner collar inside the housing 101 in controlled increments. Teeth or cogs on the indexing collar 160 engage with mating teeth or castellation defined on shoulders inside the housing 101. Each indexed position is defined by the engagement of new alignments between the teeth and castellation. The teeth can have different shapes, such as V-notch teeth to provide positive engagement and hold the inner collar in place. The teeth can be asymmetrical to facilitate rotation in one direction. The indexing can be self-locking and can resist back-driving of the inner collar.

[0091] Depending on the design requirements and constraints, other indexing mechanisms can be used for the variable orifice assembly 150. The indexing mechanisms can convert the axial movement of the indexing collar 160 into indexed rotational movement within the housing. Several axial-to-rotational indexing mechanisms can be used.

[0092] In one example, a pin and slot arrangement (i.e., an indexing slot mechanism) can be used between the indexing collar 160 and the interior flow passage 110 of the housing 101. In the pin and slot arrangement, axial shifting of the inner collar produces rotation through a slotted pattern.

[0093] For example, the indexing collar 160 can include a profiled slot, which can ride along one or more pins extending from the side of the housing 101 into the interior flow passage 110. As the indexing collar 160 is reciprocated, movement of the profiled slot along the pin can produce the incremental rotation of the indexing collar 160 to vary the alignment between the orifice port 164 and the side port 114.

[0094] FIGS. 13A-13B schematically illustrate a pin and slot indexing arrangement for the variable orifice assembly 150. FIG. 13A shows the circumference of the outer surface of the indexing collar (160) schematically rolled out. The orifice port 164 is defined in the indexing collar, and the outer surface defines a continuous slot 163 having upper and lower resting positions offset from one another.

[0095] Features of the inner surface of the interior flow passage are only shown in dashed lines and include a pin 113 and the side port 114. For stability, more than one pin can be used. The pin may or may not be spring loaded. In another example, the pin may use a spring-loaded ball. The pin engages with the stepped slot defined about the outer surface of the inner collar, which guides both the rotation and axial movement of the inner collar and produces a stepped or indexed rotation. When the indexing collar (160) is moved between upward and downward positions relative to the interior flow passage (110), for example, the pin 113 follows the slot 163, causing the indexing collar (160) to rotate and shift the alignment of the orifice port 164 with the side port 114.

[0096] Segments between upper and lower resting positions in the stepped slot can produce discrete rotational steps. One-way or two-way indexing can be used. For example, upward axial movement can rotate the inner collar, but the return stroke can be free of rotation. In two-way indexing, axial movements of the inner collar in both directions produce rotation.

[0097] In a reverse configuration, the indexing collar 160 can have the pin (113), which may or may not be spring loaded. The pin extends from the outer surface 161 of the indexing collar 160 and engages with a stepped slot (163) defined about the inner surface of the housing. The stepped slot (163) guides both the rotation and axial movement of the indexing collar 160 and produces a stepped or indexed rotation.

[0098] Similar to the pin and slot arrangement, a spline and keyway arrangement can be used for indexing. In FIGS. 14A-14B, for example, cammed ribs 113′ can be defined on the inside of the interior flow passage and can alternatingly engage cammed edges of a profiled slot 163′ defined on the outer surface 161 of the indexing collar 160. As the indexing collar 160 is reciprocated, engagement between the cammed ribs 113′ and edges of the profiled slot 163′ can produce the incremental rotation of the indexing collar 160 and vary the alignment between the orifice port 164 and the side port 114. A reverse arrangement can also be used.

[0099] In another example (not shown), an internal profile in the interior flow passage 110 can have circumferentially spaced splines and gaps (keyways) between them. The splines are not continuous, instead being staggered or interrupted to create indexing positions. The indexing collar 160 has external splines that engage with the internal splines of the interior flow passage 110. When splines align, the indexing collar 160 can resist rotation. When the indexing collar 160 is moved axially, the splines disengage, allowing rotation into the next indexed position upon re-engagement.

[0100] During indexing, the indexing collar 160 is pulled by the collet 132 in an axial upstroke. The splines are disengaged so rotational can rotate the indexing collar 160 is slightly rotated. The rotational bias can be achieved using cam surface, ramped edge, a spring, or the like. After rotation, the indexing collar 160 can be pushed down by the biasing element 168 in an axial downstroke. The splines re-engage in the next indexed rotational position. Each axial cycle rotates the indexing collar 160 by one increment based on spline / keyway spacing. Each axial stroke can produce a partial rotation as the splines shift into the next indexed position. When re-engaged, the spline can lock in a new indexed position. Segmented splines can be used for incremental rotation per axial shift, while J-Cut splines can combine axial and rotational displacement into a stepped pattern.

[0101] In another example, an axial ratchet and pawl arrangement can produce incremental rotation when the indexing collar 160 is shifted axially and teeth engage. As the indexing collar 160 is moved with an axial stroke, a pawl on the indexing collar 160 can engage with teeth or grooves along the interior flow passage 110 of the housing 101 to index the indexing collar 160 in discrete steps. Rotation in one direction is permitted, but reverse rotation is resisted or restricted. In two-way indexing, each axial stroke of the indexing collar 160 can turn the indexing collar 160 by one indexed position. A spring or biasing element can reset the pawl after each stroke. One-way indexing can be used. For example, upward axial movement can rotate the indexing collar 160, but the return stroke can be free of rotation.

[0102] In yet another example, axial movement of the indexing collar 160 can drive its rotation by following a spiral or cam profile. The indexing collar 160 can have a multi-step cam profile. Axial movement of the indexing collar 160 causes a cam follower or dog to ride along the profile, causing rotation. Locking features, such as indexed detents, can be added at intervals for positive positioning. Biased by the collar spring 168, the indexing collar 160 can be held in each indexed position.

[0103] Further still, a ball and ramp arrangement can be used so that axial movement of the indexing collar 160 drives rotary indexing. Axial force rolls balls along angled ramps. The balls can be positioned between opposing ramp surfaces on the indexing collar 160 and the housing's interior flow passage 110. Axial movement of the indexing collar 160 drives the balls along the ramps, causing rotation. Distinct indexing positions can be defined by detents.

[0104] In a J-Slot arrangement, axial movement of the indexing collar 160 follows a slot path with rotational steps. An axial stroke of the indexing collar 160 drives a pin into a J-shaped or multi-step slot. Each axial cycle shifts the pin to the next rotational position. The pin can be spring-loaded pin to ensure engagement and resetting. These and other indexing arrangements can be used and can be combined as desired.

[0105] Any referential language with respect to direction, such as up, down, upper, lower, longitudinal, lateral, vertical, horizontal, etc. is merely used to assist with explanation. The features disclosed herein can be arranged in any orientation relative to a frame of reference.

[0106] Configurations of the present disclosure can be characterized as follows:

[0107] 1. A gas lift valve (100) comprising:

[0108] a housing (101) defining an interior passage (110) having a first port (112) and a second port (114), the first port (112) being exposed to one of an annulus pressure (AP) and a tubing pressure (TP), the second port (114) being exposed to the other of the annulus pressure (AP) and the tubing pressure (TP);

[0109] a piston (130) disposed in the housing (101), the piston (130) being biased by a dome pressure (DP) in the housing (101), the piston (130) being movable in first and second axial directions with axial movement in the interior passage (110) at least in response to a pressure differential between the dome pressure (DP) and an internal pressure in the interior passage (110); and

[0110] an indexing collar (160) disposed in the interior passage (110) and defining an orifice port (164) therein, the indexing collar (160) being rotatably indexed in rotational positions in the interior passage (110) in response to the axial movement of the piston (130) in at least one of the first and second axial directions, alignment of the orifice port (164) with the first port (112) being variable based on the rotational positions of the indexing collar (160).

[0111] 2. The gas lift valve of clause 1, wherein:

[0112] the gas lift valve further comprises a check valve (140) disposed in the interior passage (110), the check valve (140) being configured to prevent communication from the second port (114) toward the first port (112) and being configured to allow communication from the first port (112) toward the second port (114);

[0113] the housing (101) defines a dome chamber (120) having the dome pressure (DP); and wherein the piston (130) comprises a bellows (135) connected between the piston (130) and the interior passage (110), the bellows (135) separating the dome chamber (120) from the interior passage (110) having the first port (112) and the second port (114); and / or

[0114] the piston (130) is movable with the axial movement in the first axial direction in response to a first of the pressure differential of the internal pressure over the dome pressure (DP), and the piston (130) is movable with the axial movement in the second axial direction in response to a second of the pressure differential of the dome pressure (DP) over the internal pressure.

[0115] 3. The gas lift valve of clause 1 or 2, wherein:

[0116] the gas lift valve (100) comprises a biasing element biasing the indexing collar (160) in the second axial direction in the interior passage (110);

[0117] the piston (130) is selectively engageable with the indexing collar (160), the indexing collar (160) being movable with the axial movement in the first axial direction by the piston (130) engaged with the indexing collar (160); and / or

[0118] the indexing collar (160) defines an internal profile (166), and the piston (130) comprises a collet disposed on a distal end of the piston (130), the collet being selectively engageable with the internal profile (166) of the indexing collar (160).

[0119] 4. The gas lift valve of clause 1, 2 or 3, wherein the indexing collar (160) moved in response to the axial movement in the first axial direction is rotatable in a first increment of the rotational positions in response to a first indexing engagement between a first intermediate cam (165a) on the indexing collar (160) with a first cam (115a) in the interior passage (110)

[0120] 5. The gas lift valve of clause 4, wherein the indexing collar (160) is movable in the second axial direction in response to the piston (130) disengaged with the indexing collar (160), the indexing collar (160) moved in the second axial direction being fixable in the rotational positions in response to a locking engagement between the indexing collar (160) and the interior passage (110) optionally wherein the indexing collar (160) is movable in the second axial direction in response to the piston (130) disengaged with the indexing collar (160), the indexing collar (160) moved in the second axial direction being rotatable in a second increment of the rotational positions in response to a second indexing engagement between a second intermediate cam (165b) on the indexing collar (160) with a second cam (115b) in the interior passage (110).

[0121] 6. The gas lift valve of any one of clauses 1 to 5, wherein the interior passage (110) defines a first cam (115a) on one side of the first port (112) and defines a second cam (115b) on an opposite side of the first port (112); and wherein the indexing collar (160) has a first intermediate cam (165a) and a second intermediate cam (165b).

[0122] 7. The gas lift valve of clause 6, wherein the first and second cams (115a-b) have an offset from one another, the first and second intermediate cams (165a-b) being configured to alternately engage the first and second cams (115a-b), the offset of the first and second cams (115a-b) being configured to rotate the indexing collar (160) in incremented rotations in response to the first and second intermediate cams (165a-b) alternately engaged with the first and second cams (115a-b).

[0123] 8. The gas lift valve of any one of clauses 1 to 5, comprising an indexing mechanism arranged between the indexing collar (160) and the interior passage (110), the indexing mechanism being configured to rotatably index the indexing collar (160) in the rotational positions in the interior passage (110) in response to the axial movement of the piston (130) in the at least one of the first and second axial directions.

[0124] 9. The gas lift valve of clause 8, wherein the indexing mechanism comprises:

[0125] a first shoulder (115a) disposed in the interior passage (110) and defining first castellations (117a) on one side of the first port (112);

[0126] a second shoulder (115b) disposed in the interior passage (110) and defining second castellations (117b) on an opposite side of the first port (112);

[0127] a first edge (165a) of the inner collar (160) defining first teeth (167a); and

[0128] a second edge (115b) of the inner collar (160) defining second teeth (167b).

[0129] 10. The gas lift valve of clause 9, wherein the first castellations (117a) are ramped; and wherein the first teeth (167a) are ramped and are configured to index in a first indexing engagement with the first castellations (117a) to rotate the indexing collar (160), optionally wherein:

[0130] the second castellations (117b) are ramped, and the second teeth (167b) are ramped and are configured to index in a second indexing engagement with the second castellations to rotate the indexing collar (160);

[0131] the second teeth (167b) of the indexing collar (160) are configured to engage in a locking engagement with the second castellations (117b); and / or

[0132] the first teeth (167a) and the first castellations (117a) match one another and are smaller than the second teeth (167b) and the second castellations (117b).

[0133] 11. The gas lift valve of clause 8, wherein the indexing mechanism comprises:

[0134] a slot profile (163) defined on an outer surface of the indexing collar (160) or on an inner surface of the interior passage (110), the slot profile (163) having resting positions offset from one another; and

[0135] at least one pin (113) extending from the outer surface or the inner surface and disposed in the slot profile (163), the at least one pin (113) being configured to ride in the slot profile (163) alternating between the resting positions.

[0136] 12. The gas lift valve of clause 8, wherein the indexing mechanism comprises:

[0137] a slot profile (163′) defined on one of an outer surface of the indexing collar (160) or on an inner surface of the interior passage (110) and having cammed ridges; and

[0138] splines (113′) defined on the other of the outer surface or the inner surface and disposed in the slot profile (163′), the splines (113′) having cammed ends alternating engaging between the cammed ridges.

[0139] 13. A method for a gas lift completion in a wellbore, the method comprising:

[0140] producing pressure differentials in an interior passage (110) of a gas lift valve (100) between an annulus pressure (AP) of the wellbore and a tubing pressure (TP) of the gas lift completion;

[0141] moving a piston (130) in first and second axial directions in the gas lift valve (100) in response to the pressure differentials; and

[0142] indexing an alignment of an orifice port (164) defined in an indexing collar (160) in the gas lift valve (100) with a first port (112) in the gas lift valve (100) by:

[0143] moving the indexing collar (160) in the first axial direction with the piston (130) engaged with the indexing collar (160) and moved in the first axial direction;

[0144] moving the indexing collar (160) in the second axial direction; and

[0145] rotating a rotational position of the indexing collar (160) by an increment with at least one indexing engagement between the indexing collar (160) and the interior passage (110) in response to the indexing collar (160) moved in at least one of the first and second axial directions.

[0146] 14. The method of clause 13, wherein moving the indexing collar (160) in the first axial direction with the piston (130) engaged with the indexing collar (160) comprises engaging a collet on the piston (130) with an internal profile (166) of the indexing collar (160), optionally wherein moving the indexing collar (160) in the second axial direction comprises biasing the indexing collar (160) in the second axial direction with a spring (168).

[0147] 15. The method of clause 13 or 14, wherein rotating the rotational position of the indexing collar (160) by the increment with the at least one indexing engagement comprises engaging a first edge (165a) of the indexing collar (160) in a first of the at least one indexing engagement with a first shoulder (115a) on a first side of the first port (112) in the gas lift valve (100) in response to the indexing collar (160) moved in the first axial direction, optionally wherein rotating the rotational position of the indexing collar (160) by the increment with the at least one indexing engagement comprises engaging a second edge (165b) of the indexing collar (160) in a second of the at least one indexing engagement with a second shoulder (115b) on a second side of the first port (112) in the gas lift valve (100) in response to the indexing collar (160) moved in the second axial direction.

[0148] The foregoing description of preferred and other embodiments is not intended to limit or restrict the scope or applicability of the inventive concepts conceived of by the Applicants. It will be appreciated with the benefit of the present disclosure that features described above in accordance with any embodiment or aspect of the disclosed subject matter can be utilized, either alone or in combination, with any other described feature, in any other embodiment or aspect of the disclosed subject matter.

[0149] In exchange for disclosing the inventive concepts contained herein, the Applicants desire all patent rights afforded by the appended claims. Therefore, it is intended that the appended claims include all modifications and alterations to the full extent that they come within the scope of the following claims or the equivalents thereof.

Examples

Embodiment Construction

[0038]Referring to FIG. 2A, a gas lift mandrel 60 is installed on tubing 20 of a wellbore completion. The mandrel 60 is shown with a gas lift valve 100 of the present disclosure installed. As shown here, the gas lift valve 100 is wireline-retrievable, but the teachings of the present disclosure can apply to other types of valves, such as tubing-retrievable valves when used with an appropriate mandrel and tubing running procedures. The gas lift valve 100 includes a variable orifice assembly 150 according to the present disclosure. The variable orifice assembly 150 may be initially in a closed condition, but is configured to open once activated, as discussed later.

[0039]While the variable orifice assembly 150 is in the closed condition, the gas lift valve 100 can be run into the tubing 20 by wireline and can be inserted into the side pocket 65 of the mandrel 60. A latch 109 of the gas lift valve 100 engages a profile 69 in the side pocket 65 to hold the gas lift valve 100 therein. Pac...

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Appl. No. 63 / 772,525 filed Mar. 15, 2023 and is filed concurrently with U.S. Non-Provisional application Ser. No. 19 / 089,232, entitled “Gas Lift Valve Having Ratcheting Orifice” (Atty. Dkt. No. 230-0854US), both of which are incorporated herein by reference in their entirety.BACKGROUND OF THE DISCLOSURE

[0002] To obtain hydrocarbon fluids from an earth formation, a wellbore is drilled into an area of interest within a formation. The wellbore may then be “completed” by inserting casing in the wellbore and setting the casing using cement. Alternatively, the wellbore may remain uncased as an (“open hole”), or it may be only partially cased. Regardless of the form of the wellbore, production tubing is run into the wellbore to convey production fluid (e.g., hydrocarbon fluid, which may also include water) to the surface.

[0003] Often, pressure within the wellbore is insufficient to cause the production fluid to naturally rise through the production tubing to the surface. In these cases, an artificial lift system can be used to carry the production fluid to the surface. One type of artificial lift system is a gas lift system, of which there are two primary types of systems: tubing-retrievable gas lift systems and wireline-retrievable gas lift systems. Each type of gas lift system uses several gas lift valves spaced along the production tubing. The gas lift valves allow gas to flow from the annulus into the production tubing so the gas can lift production fluid in the production tubing. Yet, the gas lift valves prevent fluid to flow in the opposite direction from the production tubing into the annulus.

[0004] A reverse arrangement can also be used for gas lift in which produced fluid travels up the annulus as annular flow (also referred to as revered flow). In this reverse arrangement, gas is injected into the tubing string, and the gas lift valves allow gas to flow from the tubing string to the annulus so the gas can lift production fluid in the annulus. Yet, the gas lift valves prevent fluid to flow in the opposite direction from the annulus to the tubing string.

[0005] A typical wireline-retrievable gas lift system 10 is shown in FIG. 1.

[0006] Operators inject compressed gas G into the annulus 22 between the tubing 20 and the casing 24 within a cased wellbore 26. A valve system 12 supplies the injection gas G from the surface and allows produced fluid to exit the gas lift system 10.

[0007] Side pocket mandrels 30 spaced along the production tubing 20 hold gas lift valves 40 within side pockets 32. As noted previously, the gas lift valves 40 are one-way valves that allow gas flow from the annulus 22 into the production tubing 20 and prevent reverse flow from the production tubing 20 into the annulus 22.

[0008] A production packer 14 located on the production tubing 20 forces the flow of production fluid P from a formation up through the production tubing 20 instead of up through the annulus 22. Additionally, the production packer 14 forces the gas flow from the annulus 22 into the production tubing 20 through the gas lift valves 40.

[0009] In operation, the production fluid P flows from the formation into the wellbore 26 through casing perforations 28 and then flows into the production tubing 20. When it is desired to lift the production fluid P, compressed gas G is introduced into the annulus 22, and the gas G enters from the annulus 22 through ports 34 in the mandrel's side pockets 32. Disposed inside the side pockets 32, the gas lift valves 40 control the flow of injected gas I into the production tubing 20. As the injected gas I rises to the surface, it helps to lift the production fluid P up the production tubing 20 to the surface.

[0010] Gas lift valves 40 have been used for many years to assist production of fluid to the surface. The gas lift valve 40 uses pressure-sensitive valve mechanism having a metal bellows and a piston to convert pressure into movement. Injected gas acts on the bellows to open the pressure-sensitive valve mechanism, and the gas passes through the gas lift valve 40 into the tubing string. As differential pressure is reduced on the bellows, the valve mechanism in the gas lift valve 40 can close.

[0011] Depending on the completion, other types of downhole devices may be installed in the side pocket mandrels 30. For example, “dummy” valves can be installed in the side pockets 32 of the mandrels 30 to allow for certain pressure tests to be performed. These dummy valves are not actually valves because they merely position in the mandrels 30 to seal of the mandrel's ports 34, acting as isolation devices.

[0012] With the dummy valves installed, for example, the integrity of the tubing and the casing of the completion can be tested at high pressures. After testing, the dummy valves are removed and replaced by live gas lift valves 40. Typically, wireline intervention is used to remove the dummy valves from the mandrels 30 and to then install the live gas lift valves 40 in the mandrels 30. The wireline intervention can be very time consuming, technically challenging, and expensive particularly in offshore applications.

[0013] The subject matter of the present disclosure is directed to overcoming, or at least reducing the effects of, one or more of the problems set forth above.SUMMARY OF THE DISCLOSURE

[0014] In one configuration of the present disclosure, a gas lift valve comprises a housing, a piston, and an indexing collar. The housing defines an interior passage having a first port and a second port. The first port is exposed to one of an annulus pressure and a tubing pressure, and the second port is exposed to the other of the annulus pressure and the tubing pressure. The piston is disposed in the housing and is biased by a dome pressure in the housing. The piston is movable in first and second axial directions with axial movement in the interior passage at least in response to a pressure differential between the dome pressure and an internal pressure in the interior passage. The indexing collar is disposed in the interior passage and defines an orifice port therein. The indexing collar is rotatably indexed in rotational positions in the interior passage in response to the axial movement of the piston in at least one of the first and second axial directions. Alignment of the orifice port with the first port is variable based on the rotational positions of the indexing collar.

[0015] In one arrangement, an indexing mechanism is arranged between the indexing collar and the interior passage. The indexing mechanism is configured to rotatably index the indexing collar in the rotational positions in the interior passage in response to the axial movement of the piston in the at least one of the first and second axial directions.

[0016] The indexing mechanism can comprise first and second shoulders and first and second edges. The first shoulder can be disposed in the interior passage and can define first castellations on one side of the first port. The second shoulder can be disposed in the interior passage and can define second castellations on an opposite side of the first port. The first edge of the inner collar can define first teeth; and the second edge of the inner collar can define second teeth. The first castellations can be ramped, and the first teeth can be ramped and can be configured to index in a first indexing engagement with the first castellations to rotate the indexing collar. The second castellations can also be ramped, and the second teeth can be ramped and can be configured to index in a second indexing engagement with the second castellations to rotate the indexing collar. The first teeth and the first castellations can match one another and can be smaller than the second teeth and the second castellations. Alternatively, the second teeth of the indexing collar can be configured to engage in a locking engagement with the second castellations.

[0017] In another arrangement, the indexing mechanism can comprise a slot profile and at least one pin. The slot profile can be defined on an outer surface of the indexing collar or on an inner surface of the interior passage, and the slot profile can have resting positions offset from one another. The at least one pin can extend from the outer surface or the inner surface and can be disposed in the slot profile.

[0018] The at least one pin can be configured to ride in the slot profile alternating between the resting positions.

[0019] In yet another arrangement, the indexing mechanism can comprise a slot profile and splines. The slot profile can be defined on one of an outer surface of the indexing collar or on an inner surface of the interior passage and can have cammed ridges. The splines can be defined on the other of the outer surface or the inner surface and can be disposed in the slot profile. The splines can have cammed ends alternating engaging between the cammed ridges.

[0020] In another configuration of the present disclosure, a gas lift valve comprises a housing, a piston, a collar, a collet, and an indexing arrangement. The housing defines an interior passage having a first port and a second port. The first port is exposed to one of an annulus pressure and a tubing pressure. and the second port is exposed to the other of the annulus pressure and the tubing pressure. The interior passage defines a first shoulder on one side of the first port and defines a second shoulder on an opposite side of the first port. The piston is disposed in the housing and is biased by a dome pressure in the housing. The piston is movable with axial movement in first and second axial directions in the interior passage at least in response to a pressure differential between the dome pressure and an internal pressure in the interior passage. The collar is disposed in the interior passage. The collar defines an internal profile and defines an orifice port therein. The collet is disposed on a distal end of the piston and is selectively engageable with the internal profile in the collar. The collet engaged with the internal profile of the collar is configured to move the collar with the axial movement at least in the first axial direction. The indexing arrangement is configured to rotate the collar in rotational positions in the interior passage at least in response to the collar is moved in the first axial direction. Alignment of the orifice port of the collar with the first port of the housing is variable with respect to the rotational positions of the collar.

[0021] In another configuration of the present disclosure, a method is used for a gas lift completion in a wellbore. The method comprises: producing pressure differentials in an interior passage of a gas lift valve between an annulus pressure of the wellbore and a tubing pressure of the gas lift completion; moving a piston in first and second axial directions in the gas lift valve in response to the pressure differentials; and indexing an alignment of an orifice port defined in an indexing collar in the gas lift valve with a first port in the gas lift valve. The step of indexing comprises: moving the indexing collar in the first axial direction with the piston engaged with the indexing collar and moved in the first axial direction; moving the indexing collar in the second axial direction; and rotating a rotational position of the indexing collar by an increment with at least one indexing engagement between the indexing collar and the interior passage in response to the indexing collar moved in at least one of the first and second axial directions.

[0022] The foregoing summary is not intended to summarize each potential embodiment or every aspect of the present disclosure.BRIEF DESCRIPTION OF DRAWINGS

[0023] FIG. 1 illustrates a conventional gas lift system.

[0024] FIG. 2A illustrates a gas lift mandrel with a gas lift valve of the present disclosure installed.

[0025] FIG. 2B illustrates a completion having gas lift valves according to the present disclosure.

[0026] FIGS. 3A-3B illustrate an elevational view and a cross-sectional view of a gas lift valve having an orifice varying assembly according to the present disclosure.

[0027] FIG. 4 illustrates a cross-section of the gas lift valve without features of a piston, bellows, and orifice varying assembly.

[0028] FIG. 5 illustrates a cross-section of the piston with its collet.

[0029] FIGS. 6A-6B illustrate a cross-sectional view and an elevational view of the movable collar of the orifice varying assembly relative to cam features of the housing.

[0030] FIG. 7 illustrates a cross-sectional view of a portion of the gas lift valve with the orifice varying assembly in an initial stage of operation.

[0031] FIG. 8 illustrates a cross-sectional view of the portion of the gas lift valve with the orifice varying assembly in a first stage of operation.

[0032] FIG. 9 illustrates a cross-sectional view of the portion of the gas lift valve with the orifice varying assembly in a second stage of operation.

[0033] FIG. 10 illustrates a cross-sectional view of the portion of the gas lift valve with the orifice varying assembly in a third stage of operation.

[0034] FIG. 11 illustrates a cross-sectional view of the portion of the gas lift valve with the orifice varying assembly in a fourth stage of operation.

[0035] FIG. 12 illustrates an elevational view of the side port on the gas lift valve in the fourth stage of operation.

[0036] FIGS. 13A-13B schematically illustrate another cam arrangement for the variable orifice assembly.

[0037] FIGS. 14A-14B schematically illustrate yet another cam arrangement for the variable orifice assembly.DETAILED DESCRIPTION OF THE DISCLOSURE

[0038] Referring to FIG. 2A, a gas lift mandrel 60 is installed on tubing 20 of a wellbore completion. The mandrel 60 is shown with a gas lift valve 100 of the present disclosure installed. As shown here, the gas lift valve 100 is wireline-retrievable, but the teachings of the present disclosure can apply to other types of valves, such as tubing-retrievable valves when used with an appropriate mandrel and tubing running procedures. The gas lift valve 100 includes a variable orifice assembly 150 according to the present disclosure. The variable orifice assembly 150 may be initially in a closed condition, but is configured to open once activated, as discussed later.

[0039] While the variable orifice assembly 150 is in the closed condition, the gas lift valve 100 can be run into the tubing 20 by wireline and can be inserted into the side pocket 65 of the mandrel 60. A latch 109 of the gas lift valve 100 engages a profile 69 in the side pocket 65 to hold the gas lift valve 100 therein. Packing seals 103a-b on the gas lift valve 100 isolate fluid communication between a port 66 on the mandrel 60 and the gas lift valve's side port 114 on the gas lift valve 100.

[0040] The gas lift valve 100 with the variable orifice assembly 150 can be an unloading-type of gas lift valve used for a typical tubing flow application. In this instance as will be described throughout the present disclosure, gas is injected down the annulus 22 in order to enter the tubing 20 through the mandrel 60 and the gas lift valve 100 so the injected gas can then lift production fluid up the tubing 20.

[0041] As an alternative, the gas lift valve 100 with the variable orifice assembly 150 can be used in an annular flow configuration in which gas is instead injected down the tubing 20 in order to enter the annulus 22 through the gas lift valve 100 and the mandrel 60 so the injected gas can then lift production fluid up the annulus 22. Although the annular flow configuration is less common, it is applied in certain circumstances. To achieve the annular flow configuration, features, and operation of the gas lift valve 100 and the variable orifice assembly 150 are essentially reversed, and a different form of gas lift mandrel may be used. In general, one port of the gas lift valve 100 is exposed to the tubing 20, while another port of the gas lift valve 100 is exposed to the annulus 22. The variable orifice assembly 150 operates with the pressure differential between the ports to configure the active opening of the gas lift valve 100. In this reverse arrangement, produced fluid travels up the annulus as annular flow (also referred to as revered flow). Gas is injected into the tubing string, and the gas lift valve 100 allows gas to flow from the tubing string to the annulus so the gas can lift production fluid in the annulus. Yet, the gas lift valve 100 prevents fluid to flow in the opposite direction from the annulus to the tubing string.

[0042] Instead of being conventional, the gas lift valve 100 is configured to be selectively vary the flow that can pass through the gas lift valve 100 during operation. For example, the variable orifice assembly 150 can keep the gas lift valve 100 closed so pressure testing can be performed. For pressuring testing, the tubing pressure TP can be increased in the tubing 20 to test the tubing's integrity. Alternatively, the annulus pressure TP can be increased to test the casing's integrity.

[0043] The gas lift valve 100 can also be opened when ready to inject gas through the side pocket mandrel 60 and the gas lift valve 100 for entry into the tubing 20 of the completion string. In particular, using different predetermined pressure differentials the gas lift valve 100 is configured to vary the opening and closing between the annulus pressure and the tubing pressure so the gas lift valve 100 can be used for gas injection. In this way, wireline intervention to remove a dummy valve and replace it with a live gas lift valve is not needed to test the completion's integrity as required in conventional practice. Also, workover is not needed to switch out the gas lift valve 100 for another vale with a different flow setting or to alter the gas lift valve to provide a different flow setting.

[0044] To vary the opening and closing of fluid communication, the gas lift valve 100 includes the variable orifice assembly 150, details of which are discussed later.

[0045] An example completion assembly 50 is shown in FIG. 2B having multiple gas lift valves 100 installed on tubing 20 disposed in casing 24 of a wellbore. Each of the gas lift valves 100 is installed in a gas lift mandrel 60 on the tubing 20, and each of the valves 100 has a variable orifice assembly 150 to vary the flow setting of the gas lift valve 100.

[0046] The multiple gas lift valves 100 can be used together with a shear orifice valve 70 installed at the deepest point in the completion assembly 50. The shearable orifice valve 70 has a shear open mechanism set to open at a higher pressure than the activation pressure for the variable orifice assembly 150 on the gas lift valves 100. An example of such a shearable orifice valve 70 is the “RDDK-2A Shearable Orifice Gas-Lift Valve” available from Weatherford International, Inc.

[0047] The variable orifice assemblies 150 allow the casing 24, the tubing 20, and other components (e.g., packers) in the well completion assembly 50 to be tested. Then, the gas lift valves 100 can be varied open and closed with a variable orifice. The variable orifice assemblies 150 allow gas lift operations to proceed without wireline intervention.

[0048] In one configuration, the variable orifice assemblies 150 of the gas lift valves 100 are activated in response to a predetermined pressure differential between the annulus pressure AP and the tubing pressure TP (i.e., the annulus pressure AP in the annulus 22 increased a predetermined level above the tubing pressure TP). As used herein, “annulus pressure” AP refers to the pressure in the annulus 22 between the tubing 20 and the casing 24. By contrast, “tubing pressure” TP refers to the pressure in the tubing 20 of the completion string in the wellbore.

[0049] For example, the tubing 20 and the annulus 22 are filled with completion fluid, which creates hydro-static pressure on each inlet and outlet side of the ports 112, 114 of the gas lift valves 100. With communication through the ports 112, 114 closed, operators can first perform a tubing test by increasing the tubing pressure TP to a set test pressure. This tests the integrity of the tubing 20 of the completion string. The operators then bleed off the tubing pressure TP.

[0050] At this point, operators increase the annulus pressure AP to apply a set test pressure to the annulus 22 from the surface. This increase in annulus pressure AP can test packers (not shown) and the casing 24 of the completion assembly 50 by creating a pressure differential between the casing 24 and the tubing 20.

[0051] With the casing's integrity tested, the annulus pressure AP is then increased to a first predetermined level above the set test pressure to open the variable orifice assemblies 150 of the gas lift valves 100. The annulus pressure AP can then be increased even further to a second, higher predetermined level to open the shearable orifice valve 70.

[0052] Once the annulus pressure AP reaches the opening pressure differential of the shearable orifice valve 70, the annulus and tubing pressures AP, TP throughout the wellbore will equalize. With the pressures AP, TP then equalized, the gas lift valves 100a-c are now in open conditions and ready for gas injection operations.

[0053] The variable orifice assemblies 150 of the gas lift valves 100 can be configured to open after testing in response to increased tubing pressure TP. (This installation may not use the shearable orifice valve 70 on the completion assembly 50.) During testing, for example, the tubing 20 and the annulus 22 are filled with completion fluid, which creates hydro-static pressure on each side of the gas lift valves 100. Operators first perform a casing integrity test by increasing the annulus pressure AP from the surface to a set test pressure. This increase in annulus pressure AP tests any packers and tests the casing 24 of the completion assembly 50 by creating a pressure differential in the annulus 22 relative to the tubing 20. The annulus pressure AP is then bled off.

[0054] Operators then increase the tubing pressure TP to a predetermined level that opens the variable orifice assemblies 150 of the gas lift valves 100. Although the gas lift valves 100 are now open, certain check valves (e.g., check valve 140 in FIG. 3A) in the gas lift valves 100 will close and prevent reverse flow of pressure from the tubing 20 to the annulus 22. The operators can now test the tubing integrity by increasing the tubing pressure TP to a set test level. The tubing pressure TP is then bled off, and the gas lift valves 100a-c are now in open conditions and ready for gas injection.

[0055] After testing, the amount of flow that can pass through the gas lift valves 100 can then be varied by cycling the pressure differentials between the annulus pressure AP and the tubing pressure TP. The cycling varies the available orifice for flow through the gas lift valves 100 in a manner discussed in more detail below.

[0056] Having an understanding of how an variable orifice assembly 150 of the present disclosure is used on a gas lift valve 100 in a completion assembly 50, discussion now turns to particular details of the different configurations of the variable orifice assembly 150.

[0057] FIGS. 3A-3B illustrate an elevational view and a cross-sectional view of a gas lift valve 100 having a variable orifice assembly 150 according to the present disclosure. As shown, the gas lift valve 100 is an unloading-type of gas lift valve, and the variable orifice assembly 150 is configured to open and close the gas lift valve 100 in response to pressure differentials between the annulus pressure AP and the tubing pressure TP.

[0058] The gas lift valve 100 can be configured as a tubing-conveyed valve or can be a wireline retrievable valve. In the configuration shown in FIG. 3A, for example, the gas lift valve 100 is wireline retrievable and can be removable from and (installable in) a side pocket of a side pocket mandrel (60) while the production tubing string remains downhole within the wellbore. A kickover tool (not shown) or other known deployment tool can be used to retrieve and install the gas lift valve 100. Any suitable latch 109 known in the art can be used for deploying the gas lift valve 100 in a side pocket mandrel (60). In general, the latch 109 threads to the tail piece 105 of the gas lift valve 100. A latching profile can be engaged by the retrieving tool. A frangible member, such as a shear pin, disposed of on the body, releasably connects the latch mechanism within a latch recess area. A spring on the latch body is biased against a latch ring abutted against a latch stop. The latch ring and latch stop cooperate to provide means for connecting the latching mechanism within the latch recess area to anchor the gas lift valve 100 within a side pocket.

[0059] The gas lift valve 100 has a housing 101, a piston 130, and a variable orifice assembly 150. The housing 101, which is shown in cross-section with some internal components missing, defines an interior flow passage 110 therein and has an end port 112 and a side port 114. In one configuration, the end port 112 can be an outlet exposed to tubing pressure TP of the tubing, while the side port 114 can be an inlet exposed to the annulus pressure AP. A reverse arrangement of exposure can be used.

[0060] For ease of assembly, the housing 101 can be composed of several housing components connected together. For example, the housing components can include an end port housing 102, a side port housing 104, a bellows adapter 106, a dome housing 108, and a tail piece 105. The end port housing 102 has the end port 112 communicating with interior flow passage 110, and the side port housing 104 has the side port 114 communicating with the interior flow passage 110. A tail plug 107 and a core valve 122 on the tail piece 105 holds a dome pressure in a dome chamber 120 of the gas lift valve 100. Typically, the dome chamber 120 can hold a compressed gas, typically nitrogen, which is filled through the core valve 122 in the tail piece 105.

[0061] The housing 101 has annular seal 103a-b, such as packing stacks, disposed about the housing 101 on both sides of the side port 114. In this way, the annular seals 103a-b seals the side port 114 from the end port 112 and isolates the annulus pressure AP and the tubing pressure TP when installed in a typical side-pocket gas lift mandrel (e.g., 60; FIG. 2A). Accordingly, the gas lift valve 100 run into the mandrel (60) is exposed to annular pressure AP through the side port 114 communicating with the mandrel's injection ports (66), and the end port 112 is exposed to tubing pressure TP. Thus, the term “annular pressure” used in reference to the gas lift valve 100 refers to the pressure in the wellbore annulus at the side port 114 of the gas lift valve 100, whereas the term “tubing pressure” refers to the pressure in the completion string at the end port 112 of the gas lift valve 100.

[0062] Internally, the gas lift valve 100 uses a pressure-sensitive mechanism to control gas injection. In particular, a piston 130 disposed in the housing 101 includes a bellows 135 connected between the piston 130 and the interior flow passage 110. The gas lift valve 100 uses this bellows 135 as a membrane that separates the dome chamber 120 from the interior flow passage 110 exposed to the end port 112 and the side port 114. The dome chamber 120 and the bellows 135 bias movement the piston 130, and the piston 130 is movable in the gas lift valve 100 in response to pressure differential across the bellows 135.

[0063] A collet 132 on the piston 130 interacts with the variable orifice assembly 150 discussed in more detail below. (FIG. 5 shows an isolation view of the piston 130 and collet 132 in cross-section.) The interaction of the collet 132 with the variable orifice assembly 150 can alter how much flow of injected gas entering from the side port 114 can pass through the interior flow passage 110 to the housing's end port 112 (or vice versa depending on the installation).

[0064] To prevent reverse flow from the tubing to the annulus through the gas lift valve 100, a check valve 140 can be used in the interior flow passage 110 of the gas lift valve 100. As is typical, the check valve 140 can be a dart valve with ports and can have a spring that biases the check valve 140 toward a seat.

[0065] Rather than having a conventional inlet and outlet for passage of injected gas directly out of the gas lift valve 100 from the interior flow passage 110 to a completion string (not shown), the gas lift valve 100 of FIGS. 3A-3B includes the variable orifice assembly 150 installed at the side port 114 for controlling fluid communication with the interior flow passage 110. This variable orifice assembly 150 can vary the amount of fluid communication through the gas lift valve 100 in a manner described latter.

[0066] In general, the variable orifice assembly 150 includes an indexing collar 160 disposed in the interior flow passage 110. The indexing collar 160 has a bore 162 and defines one or more orifice ports 164 (one shown) therein. (FIGS. 6A-6B show an isolated, cross-sectional view and an isolated, elevational view of the indexing collar 160 relative to cam features of the housing (101). Briefly, the indexing collar 160 has first and second (upper and lower) edges or intermediate cams 165a-b, which are illustrated relative to first and second (upper and lower) shoulders or cams 115a-b defined in the interior flow passage (110) of the housing (101). In this arrangement, the intermediate cams 165a-b include ramped teeth 167a-b, and the housing's cams 115a-b include ramped castellations or teeth 117a-b.)

[0067] During operation, the indexing collar 160 is rotatably indexed in rotational positions in the interior flow passage 110 in response to the axial movement of the pressure-sensitive piston 130 in at least one of the first and second axial directions. Alignment of the orifice port 164 with the first port 114 is variable with respect to the rotational positions of the indexing collar 160.

[0068] In particular, the piston 130, being sensitive to the pressure, is movable with axial movement in a first (upward) direction in the interior flow passage 110 in response to a first pressure differential between the first and second ports 112 and 114. The collet 132 of the piston 130 is selectively engageable inside the collar's bore 162, and the indexing collar 160 is movable with the axial movement by the pressure-sensitive piston 130 engaged with the indexing collar 160. As noted, for example, the piston 130 includes the collet 132 disposed on a distal end of the piston 130. The collet132 is selectively engageable with an internal profile 166 of the indexing collar 160. In this way, the indexing collar 160 is movable in the first (upward) direction by the collet 132 engaged with an internal profile 166 of the indexing collar 160. The indexing collar 160 moved in the first (upward) direction is rotatable in an increment of the rotational positions in response to an indexing engagement (115a, 165a) between the indexing collar 160 and the interior flow passage 110.

[0069] The engagement of the collet 132 with the profile 166 can permit the incremental rotation of the indexing collar 160 when it is indexed. The collet 132 includes fingers 134 separated by flexing slots, and the fingers 134 have keys 136, which can engage in the internal profile 166.

[0070] In turn, a biasing element 168, such as a collar spring, biases the indexing collar 160 in a second (downward) direction in the interior flow passage 110. Biased by the collar spring 168, the indexing collar 160 is also movable in the second (downward) direction in response to the collet 132 of the piston 130 being disengaged with the indexing collar 160. The indexing collar 160 moved in the (downward) direction is at least fixable in the given rotational position in response to a locking engagement (115b, 165b) between the indexing collar 160 and the interior flow passage 110. Moreover, the indexing collar 160 moved with the second direction can be rotatable in another increment of the rotational positions in response to an indexing engagement (115b, 165b) between the indexing collar 160 and the interior flow passage 110.

[0071] In one configuration for the indexing engagement (115a, 165a), the interior flow passage 110 defines a first (upper) shoulder 115a on a first (upper) side of the side port 114, and the indexing collar 160 defines a first (upper) edge 165a. The upper shoulder 115a and the upper edge 165a can be ramped or cammed. In particular and as also shown in FIGS. 6A-6B, the upper edge 165a can include a plurality of ramped teeth (167a) disposed circumferentially about the upper end of the indexing collar 160, and the upper shoulder 115a can include a plurality of ramped castellations (117a) disposed circumferentially thereabout. As the ramped teeth (167a) engage the ramped castellations (117a), the offset of the ramped teeth (167a) and castellations (117a) can cause the indexing collar 160 to rotate an increment, which varies the alignment of the orifice port 164 with the side port 114.

[0072] During operation, the piston 130 can be moved with the second axial movement in the interior flow passage 110 in response to a second pressure differential in the gas lift valve 100 opposite to the first pressure differential. The indexing collar 160 can remain fixed in the given rotational position with the locking engagement regardless of the pressure-sensitive piston 130 being engaged in the second axial movement with the indexing collar 160.

[0073] In one configuration, the locking engagement (115b, 165b) can also use an indexing engagement to produce an increment in the rotational position. Accordingly, the interior flow passage 110 defines a second (lower) shoulder 115b on a second (lower) side of the side port 114, and the indexing collar 160 defines a second (lower) edge 165b. The lower shoulder 115b and the edge 165b can be ramped or cammed. In particular and as also shown in FIGS. 6A-6B, the lower edge 165b can include a plurality of ramped teeth (167b) disposed circumferentially thereabout, and the lower shoulder 115b can include a plurality of ramped castellations (117b) disposed circumferentially thereabout. As the ramped teeth (167b) engage with the ramped castellations (117b), offset of the ramped teeth (167b) and castellations (117b) may cause the indexing collar 160 to rotate a further increment, which varies the alignment of the orifice port 164 with the side port 114. Preferably, the ramped teeth (167a) and castellations (117a) of the upper edge 165a and the upper shoulder 115a are smaller than the ramped teeth (167b) and castellations (117b) of the lower edge 165b and the lower shoulder 115b, which can enhance the offset used to rotate the indexing collar 160.

[0074] Alternatively, the incremental rotation of the indexing collar 160 can be achieved exclusively with the upper engagement (115a, 165a), and the lower teeth and castellations may not be ramped or cammed, may not have any offset, and may merely align to engage one another. The reverse is also possible in which the incremental rotational can be achieved exclusively with the lower engagement (115b, 165b).

[0075] Other configurations can be used for the indexing and locking engagement of the indexing collar 160. In one example discussed below with reference to FIGS. 13A-13B, a pin and slot arrangement can be used between the indexing collar 160 and the interior flow passage 110 of the housing 101. The indexing collar 160 can include a profiled slot, which can ride along one or more pins extending in the side of the housing 101 into the interior flow passage 110. As the indexing collar 160 is reciprocated, movement of the profiled slot along the pin can produce the incremental rotation of the indexing collar 160 to vary the alignment between the orifice port 164 and the side port 114.

[0076] In another example discussed below with reference to FIGS. 14A-14B, a profiled slot can be defined on the outside of the indexing collar 160 and can be engaged with complementary cammed ribs defined on the inside surface of the passage. As the indexing collar 160 is reciprocated, engagement between the cammed ribs and profiled slot produce the incremental rotation of the indexing collar 160 and vary the alignment between the orifice port 164 and the side port 114. These and other indexing arrangements can be used.

[0077] FIG. 7 illustrates a cross-sectional view of a portion of the disclosed gas lift valve 100 with the variable orifice assembly 150 in an initial stage of operation. No load has been applied to the pressure-sensitive piston (130) by a pressure differential. As can be seen, the orifice port 164 of the indexing collar 160 is misaligned with the side port 114 of the housing 101 so that a reduced or choked flow condition can be achieved. As generally shown, the orifice port 164 can include a tapered, cutout, teardrop, or another non-circular shape so that variations in flow can be achieved. Other configurations can be used. For example, the indexing collar 160 may include various smaller orifice ports 164 that can be consecutively aligned with a larger side port 114 to vary the orifice area for fluid communication.

[0078] Although not explicitly shown, sliding seals can be used between the indexing collar 160 and the interior flow passage 110 to seal off communication of the orifice port 164 with the side port 114. Because the orifice port 164 would still be radially exposed to the side port 114 if only circumferential seals (e.g., radial O-ring seals) were used, other forms of sealed isolation could be used if desired.

[0079] During operations, the first pressure differential is produced in the interior flow passage 110 of the gas lift valve 100 between annulus pressure AP of the wellbore and tubing pressure TP of the gas lift completion. For example, FIG. 8 illustrates a cross-sectional view of the portion of the disclosed gas lift valve 100 with the variable orifice assembly 150 in a first stage of operation. The application of pressure has begun, producing a greater pressure in the interior flow passage 110 compared to the charge pressure in the dome chamber (120). In response to the first pressure differential, the piston 130 is subject to the first pressure differential across the bellows (135) separating the charge pressure in the dome chamber (120) from the pressure present in the interior flow passage 110. The piston 130 starts to move with a first (upward) movement in the gas lift valve 100 in response to the first pressure differential. As can be seen, the lower ramped teeth 167b lose contact with the lower ramped constellations 117b as the piston (130 moves the collet 132 upward and starts to shift the indexing collar 160 upward.

[0080] Pressure can be communicated into the interior flow passage 110 either from annulus pressure or tubing pressure via the ports 112, 114. Because some fluid communication can be achieved between the side port 114 and orifice port 164 and can bypass the misalignment of the indexing collar 160, annulus pressure from the side port 114 can still enter the interior flow passage 110 to produce the desired pressure differential.

[0081] FIG. 9 illustrates a cross-sectional view of the portion of the disclosed gas lift valve 100 with the variable orifice assembly 150 in a second stage of operation.

[0082] The continued application of pressure in the interior flow passage 110 has moved the pressure-sensitive piston 130 and collet 132 further upward, shifting the indexing collar 160 so that the upper teeth 167a engage with the upper castellations 117a. An alignment of the orifice port 164 defined in the indexing collar 160 is thereby varied relative to the side port 114 as the piston 130 engages with the indexing collar 160, as the indexing collar 160 then moves with the first (upward) movement, and the rotational position of the indexing collar 160 is incremented by the indexing engagement between the indexing collar 160 and the interior flow passage 110.

[0083] FIG. 10 illustrates a cross-sectional view of the portion of the disclosed gas lift valve 100 with the variable orifice assembly 150 in a third stage of operation. The continued application of pressure causes the collet's fingers 134 to collapse so the keys 136 start to release from the profile 166 of the indexing collar 160. The collar spring 168 can then push the indexing collar 160 in the downward direction as the collet 132 loses its engagement with the indexing collar 160.

[0084] FIG. 11 illustrates a cross-sectional view of the portion of the disclosed gas lift valve 100 with the variable orifice assembly 150 in a fourth stage of operation.

[0085] The continued application of pressure has caused the collet's keys 136 to be released completely from the profile 166 of the indexing collar 160. The biasing force of the collar spring 168 forces the indexing collar 160 downward so that the lower teeth 167b engage the lower castellations 117b. This produces an additional rotation of the indexing collar 160, varying the rotational position of the orifice port 164 to the side port 114. The indexing collar 160 is now fixed in the given rotational position with the locking engagement between the indexing collar 160 and the interior flow passage 110.

[0086] When the application pressure is reduced, a reverse pressure differential can result in the charge pressure in the dome chamber 120 being greater than the pressure in the interior flow passage 110. The piston 130 can move downward. The collet 132 can collapse and re-enter inside the bore 162 of the indexing collar 160 so that the gas lift valve 100 is reset. Even with the re-entry of the collet 132, the existing alignment between the orifice port 164 and the side port 114 can be maintained because the downward movement of the collet 132 against the indexing collar 160 will not rotate the indexing collar 160, which remains fixed by the locking engagement between the ramped teeth and castellations 117b, 167b.

[0087] As can be seen in FIG. 12, the incremented rotation of the indexing collar 160 has exposed a portion of the orifice port 164 with the gas lift valve's side port 114. Repeated applications and releases of pressure as discussed above can rotate the indexing collar 160. Different alignments can be achieved between the orifice port 164 of the side port 114. The different alignments can vary the available orifice area through which fluid (e.g., injected gas) can communicate.

[0088] The variable orifice assembly 150 allows the orifice size to be changed in the gas lift valve 100 without needing workover. The variable orifice assembly 150 allows a new orifice size to be utilized each time an operator reduces and reapplies casing pressure during gas injection. The variable orifice assembly 150 uses the collet 132 attached to the piston 130, which is bellows-biased and pressure sensitive, to grab and release the indexing collar 160 when casing pressure is reduced and then reapplied. The indexing collar 160 rotates to either allow or interfere with the side port 114 to change the orifice size.

[0089] The fingers 134 of the collet 132 will travel with the application and reduction of the casing pressure to grab and release the indexing collar 160, which is biased with the collar spring 168. The indexing collar 160 can have a teardrop shaped opening that interfaces with the housing's side port 114 allowing communication between annulus and tubing. The indexing collar 160 also contains teeth 167a-b on each end that interacts with castellations 117a-b on the housing 101, which are out of phase with each other. When the collet's fingers 134 grab the indexing collar 160, the indexing collar 160 is rotated when it begins interacting with the housing castellations 117a-b. With continued casing pressure, the collet 132 eventually releases the indexing collar 160, which is then biased to the lower castellations 117a on the other end of the housing 101 by the collar spring 168. This causes further rotation of the indexing collar 160. The repetition of the casing pressure cycle causes the indexing collar 160 to continue rotation that changes the amount of orifice port 164 is exposed to the housing's side port 114, changing the flow area (or orifice size) of the variable orifice assembly 150.

[0090] As noted above, the variable orifice assembly 150 can use cams to produce the indexed rotation of the indexing collar 160 that changes the alignment of the orifice port 164 and the side port 114. For example, the offset teeth and castellations disclosed above is one of several mechanisms to index or rotate the inner collar inside the housing 101 in controlled increments. Teeth or cogs on the indexing collar 160 engage with mating teeth or castellation defined on shoulders inside the housing 101. Each indexed position is defined by the engagement of new alignments between the teeth and castellation. The teeth can have different shapes, such as V-notch teeth to provide positive engagement and hold the inner collar in place. The teeth can be asymmetrical to facilitate rotation in one direction. The indexing can be self-locking and can resist back-driving of the inner collar.

[0091] Depending on the design requirements and constraints, other indexing mechanisms can be used for the variable orifice assembly 150. The indexing mechanisms can convert the axial movement of the indexing collar 160 into indexed rotational movement within the housing. Several axial-to-rotational indexing mechanisms can be used.

[0092] In one example, a pin and slot arrangement (i.e., an indexing slot mechanism) can be used between the indexing collar 160 and the interior flow passage 110 of the housing 101. In the pin and slot arrangement, axial shifting of the inner collar produces rotation through a slotted pattern.

[0093] For example, the indexing collar 160 can include a profiled slot, which can ride along one or more pins extending from the side of the housing 101 into the interior flow passage 110. As the indexing collar 160 is reciprocated, movement of the profiled slot along the pin can produce the incremental rotation of the indexing collar 160 to vary the alignment between the orifice port 164 and the side port 114.

[0094] FIGS. 13A-13B schematically illustrate a pin and slot indexing arrangement for the variable orifice assembly 150. FIG. 13A shows the circumference of the outer surface of the indexing collar (160) schematically rolled out. The orifice port 164 is defined in the indexing collar, and the outer surface defines a continuous slot 163 having upper and lower resting positions offset from one another.

[0095] Features of the inner surface of the interior flow passage are only shown in dashed lines and include a pin 113 and the side port 114. For stability, more than one pin can be used. The pin may or may not be spring loaded. In another example, the pin may use a spring-loaded ball. The pin engages with the stepped slot defined about the outer surface of the inner collar, which guides both the rotation and axial movement of the inner collar and produces a stepped or indexed rotation. When the indexing collar (160) is moved between upward and downward positions relative to the interior flow passage (110), for example, the pin 113 follows the slot 163, causing the indexing collar (160) to rotate and shift the alignment of the orifice port 164 with the side port 114.

[0096] Segments between upper and lower resting positions in the stepped slot can produce discrete rotational steps. One-way or two-way indexing can be used. For example, upward axial movement can rotate the inner collar, but the return stroke can be free of rotation. In two-way indexing, axial movements of the inner collar in both directions produce rotation.

[0097] In a reverse configuration, the indexing collar 160 can have the pin (113), which may or may not be spring loaded. The pin extends from the outer surface 161 of the indexing collar 160 and engages with a stepped slot (163) defined about the inner surface of the housing. The stepped slot (163) guides both the rotation and axial movement of the indexing collar 160 and produces a stepped or indexed rotation.

[0098] Similar to the pin and slot arrangement, a spline and keyway arrangement can be used for indexing. In FIGS. 14A-14B, for example, cammed ribs 113′ can be defined on the inside of the interior flow passage and can alternatingly engage cammed edges of a profiled slot 163′ defined on the outer surface 161 of the indexing collar 160. As the indexing collar 160 is reciprocated, engagement between the cammed ribs 113′ and edges of the profiled slot 163′ can produce the incremental rotation of the indexing collar 160 and vary the alignment between the orifice port 164 and the side port 114. A reverse arrangement can also be used.

[0099] In another example (not shown), an internal profile in the interior flow passage 110 can have circumferentially spaced splines and gaps (keyways) between them. The splines are not continuous, instead being staggered or interrupted to create indexing positions. The indexing collar 160 has external splines that engage with the internal splines of the interior flow passage 110. When splines align, the indexing collar 160 can resist rotation. When the indexing collar 160 is moved axially, the splines disengage, allowing rotation into the next indexed position upon re-engagement.

[0100] During indexing, the indexing collar 160 is pulled by the collet 132 in an axial upstroke. The splines are disengaged so rotational can rotate the indexing collar 160 is slightly rotated. The rotational bias can be achieved using cam surface, ramped edge, a spring, or the like. After rotation, the indexing collar 160 can be pushed down by the biasing element 168 in an axial downstroke. The splines re-engage in the next indexed rotational position. Each axial cycle rotates the indexing collar 160 by one increment based on spline / keyway spacing. Each axial stroke can produce a partial rotation as the splines shift into the next indexed position. When re-engaged, the spline can lock in a new indexed position. Segmented splines can be used for incremental rotation per axial shift, while J-Cut splines can combine axial and rotational displacement into a stepped pattern.

[0101] In another example, an axial ratchet and pawl arrangement can produce incremental rotation when the indexing collar 160 is shifted axially and teeth engage. As the indexing collar 160 is moved with an axial stroke, a pawl on the indexing collar 160 can engage with teeth or grooves along the interior flow passage 110 of the housing 101 to index the indexing collar 160 in discrete steps. Rotation in one direction is permitted, but reverse rotation is resisted or restricted. In two-way indexing, each axial stroke of the indexing collar 160 can turn the indexing collar 160 by one indexed position. A spring or biasing element can reset the pawl after each stroke. One-way indexing can be used. For example, upward axial movement can rotate the indexing collar 160, but the return stroke can be free of rotation.

[0102] In yet another example, axial movement of the indexing collar 160 can drive its rotation by following a spiral or cam profile. The indexing collar 160 can have a multi-step cam profile. Axial movement of the indexing collar 160 causes a cam follower or dog to ride along the profile, causing rotation. Locking features, such as indexed detents, can be added at intervals for positive positioning. Biased by the collar spring 168, the indexing collar 160 can be held in each indexed position.

[0103] Further still, a ball and ramp arrangement can be used so that axial movement of the indexing collar 160 drives rotary indexing. Axial force rolls balls along angled ramps. The balls can be positioned between opposing ramp surfaces on the indexing collar 160 and the housing's interior flow passage 110. Axial movement of the indexing collar 160 drives the balls along the ramps, causing rotation. Distinct indexing positions can be defined by detents.

[0104] In a J-Slot arrangement, axial movement of the indexing collar 160 follows a slot path with rotational steps. An axial stroke of the indexing collar 160 drives a pin into a J-shaped or multi-step slot. Each axial cycle shifts the pin to the next rotational position. The pin can be spring-loaded pin to ensure engagement and resetting. These and other indexing arrangements can be used and can be combined as desired.

[0105] Any referential language with respect to direction, such as up, down, upper, lower, longitudinal, lateral, vertical, horizontal, etc. is merely used to assist with explanation. The features disclosed herein can be arranged in any orientation relative to a frame of reference.

[0106] Configurations of the present disclosure can be characterized as follows:

[0107] 1. A gas lift valve (100) comprising:

[0108] a housing (101) defining an interior passage (110) having a first port (112) and a second port (114), the first port (112) being exposed to one of an annulus pressure (AP) and a tubing pressure (TP), the second port (114) being exposed to the other of the annulus pressure (AP) and the tubing pressure (TP);

[0109] a piston (130) disposed in the housing (101), the piston (130) being biased by a dome pressure (DP) in the housing (101), the piston (130) being movable in first and second axial directions with axial movement in the interior passage (110) at least in response to a pressure differential between the dome pressure (DP) and an internal pressure in the interior passage (110); and

[0110] an indexing collar (160) disposed in the interior passage (110) and defining an orifice port (164) therein, the indexing collar (160) being rotatably indexed in rotational positions in the interior passage (110) in response to the axial movement of the piston (130) in at least one of the first and second axial directions, alignment of the orifice port (164) with the first port (112) being variable based on the rotational positions of the indexing collar (160).

[0111] 2. The gas lift valve of clause 1, wherein:

[0112] the gas lift valve further comprises a check valve (140) disposed in the interior passage (110), the check valve (140) being configured to prevent communication from the second port (114) toward the first port (112) and being configured to allow communication from the first port (112) toward the second port (114);

[0113] the housing (101) defines a dome chamber (120) having the dome pressure (DP); and wherein the piston (130) comprises a bellows (135) connected between the piston (130) and the interior passage (110), the bellows (135) separating the dome chamber (120) from the interior passage (110) having the first port (112) and the second port (114); and / or

[0114] the piston (130) is movable with the axial movement in the first axial direction in response to a first of the pressure differential of the internal pressure over the dome pressure (DP), and the piston (130) is movable with the axial movement in the second axial direction in response to a second of the pressure differential of the dome pressure (DP) over the internal pressure.

[0115] 3. The gas lift valve of clause 1 or 2, wherein:

[0116] the gas lift valve (100) comprises a biasing element biasing the indexing collar (160) in the second axial direction in the interior passage (110);

[0117] the piston (130) is selectively engageable with the indexing collar (160), the indexing collar (160) being movable with the axial movement in the first axial direction by the piston (130) engaged with the indexing collar (160); and / or

[0118] the indexing collar (160) defines an internal profile (166), and the piston (130) comprises a collet disposed on a distal end of the piston (130), the collet being selectively engageable with the internal profile (166) of the indexing collar (160).

[0119] 4. The gas lift valve of clause 1, 2 or 3, wherein the indexing collar (160) moved in response to the axial movement in the first axial direction is rotatable in a first increment of the rotational positions in response to a first indexing engagement between a first intermediate cam (165a) on the indexing collar (160) with a first cam (115a) in the interior passage (110)

[0120] 5. The gas lift valve of clause 4, wherein the indexing collar (160) is movable in the second axial direction in response to the piston (130) disengaged with the indexing collar (160), the indexing collar (160) moved in the second axial direction being fixable in the rotational positions in response to a locking engagement between the indexing collar (160) and the interior passage (110) optionally wherein the indexing collar (160) is movable in the second axial direction in response to the piston (130) disengaged with the indexing collar (160), the indexing collar (160) moved in the second axial direction being rotatable in a second increment of the rotational positions in response to a second indexing engagement between a second intermediate cam (165b) on the indexing collar (160) with a second cam (115b) in the interior passage (110).

[0121] 6. The gas lift valve of any one of clauses 1 to 5, wherein the interior passage (110) defines a first cam (115a) on one side of the first port (112) and defines a second cam (115b) on an opposite side of the first port (112); and wherein the indexing collar (160) has a first intermediate cam (165a) and a second intermediate cam (165b).

[0122] 7. The gas lift valve of clause 6, wherein the first and second cams (115a-b) have an offset from one another, the first and second intermediate cams (165a-b) being configured to alternately engage the first and second cams (115a-b), the offset of the first and second cams (115a-b) being configured to rotate the indexing collar (160) in incremented rotations in response to the first and second intermediate cams (165a-b) alternately engaged with the first and second cams (115a-b).

[0123] 8. The gas lift valve of any one of clauses 1 to 5, comprising an indexing mechanism arranged between the indexing collar (160) and the interior passage (110), the indexing mechanism being configured to rotatably index the indexing collar (160) in the rotational positions in the interior passage (110) in response to the axial movement of the piston (130) in the at least one of the first and second axial directions.

[0124] 9. The gas lift valve of clause 8, wherein the indexing mechanism comprises:

[0125] a first shoulder (115a) disposed in the interior passage (110) and defining first castellations (117a) on one side of the first port (112);

[0126] a second shoulder (115b) disposed in the interior passage (110) and defining second castellations (117b) on an opposite side of the first port (112);

[0127] a first edge (165a) of the inner collar (160) defining first teeth (167a); and

[0128] a second edge (115b) of the inner collar (160) defining second teeth (167b).

[0129] 10. The gas lift valve of clause 9, wherein the first castellations (117a) are ramped; and wherein the first teeth (167a) are ramped and are configured to index in a first indexing engagement with the first castellations (117a) to rotate the indexing collar (160), optionally wherein:

[0130] the second castellations (117b) are ramped, and the second teeth (167b) are ramped and are configured to index in a second indexing engagement with the second castellations to rotate the indexing collar (160);

[0131] the second teeth (167b) of the indexing collar (160) are configured to engage in a locking engagement with the second castellations (117b); and / or

[0132] the first teeth (167a) and the first castellations (117a) match one another and are smaller than the second teeth (167b) and the second castellations (117b).

[0133] 11. The gas lift valve of clause 8, wherein the indexing mechanism comprises:

[0134] a slot profile (163) defined on an outer surface of the indexing collar (160) or on an inner surface of the interior passage (110), the slot profile (163) having resting positions offset from one another; and

[0135] at least one pin (113) extending from the outer surface or the inner surface and disposed in the slot profile (163), the at least one pin (113) being configured to ride in the slot profile (163) alternating between the resting positions.

[0136] 12. The gas lift valve of clause 8, wherein the indexing mechanism comprises:

[0137] a slot profile (163′) defined on one of an outer surface of the indexing collar (160) or on an inner surface of the interior passage (110) and having cammed ridges; and

[0138] splines (113′) defined on the other of the outer surface or the inner surface and disposed in the slot profile (163′), the splines (113′) having cammed ends alternating engaging between the cammed ridges.

[0139] 13. A method for a gas lift completion in a wellbore, the method comprising:

[0140] producing pressure differentials in an interior passage (110) of a gas lift valve (100) between an annulus pressure (AP) of the wellbore and a tubing pressure (TP) of the gas lift completion;

[0141] moving a piston (130) in first and second axial directions in the gas lift valve (100) in response to the pressure differentials; and

[0142] indexing an alignment of an orifice port (164) defined in an indexing collar (160) in the gas lift valve (100) with a first port (112) in the gas lift valve (100) by:

[0143] moving the indexing collar (160) in the first axial direction with the piston (130) engaged with the indexing collar (160) and moved in the first axial direction;

[0144] moving the indexing collar (160) in the second axial direction; and

[0145] rotating a rotational position of the indexing collar (160) by an increment with at least one indexing engagement between the indexing collar (160) and the interior passage (110) in response to the indexing collar (160) moved in at least one of the first and second axial directions.

[0146] 14. The method of clause 13, wherein moving the indexing collar (160) in the first axial direction with the piston (130) engaged with the indexing collar (160) comprises engaging a collet on the piston (130) with an internal profile (166) of the indexing collar (160), optionally wherein moving the indexing collar (160) in the second axial direction comprises biasing the indexing collar (160) in the second axial direction with a spring (168).

[0147] 15. The method of clause 13 or 14, wherein rotating the rotational position of the indexing collar (160) by the increment with the at least one indexing engagement comprises engaging a first edge (165a) of the indexing collar (160) in a first of the at least one indexing engagement with a first shoulder (115a) on a first side of the first port (112) in the gas lift valve (100) in response to the indexing collar (160) moved in the first axial direction, optionally wherein rotating the rotational position of the indexing collar (160) by the increment with the at least one indexing engagement comprises engaging a second edge (165b) of the indexing collar (160) in a second of the at least one indexing engagement with a second shoulder (115b) on a second side of the first port (112) in the gas lift valve (100) in response to the indexing collar (160) moved in the second axial direction.

[0148] The foregoing description of preferred and other embodiments is not intended to limit or restrict the scope or applicability of the inventive concepts conceived of by the Applicants. It will be appreciated with the benefit of the present disclosure that features described above in accordance with any embodiment or aspect of the disclosed subject matter can be utilized, either alone or in combination, with any other described feature, in any other embodiment or aspect of the disclosed subject matter.

[0149] In exchange for disclosing the inventive concepts contained herein, the Applicants desire all patent rights afforded by the appended claims. Therefore, it is intended that the appended claims include all modifications and alterations to the full extent that they come within the scope of the following claims or the equivalents thereof.

Examples

Embodiment Construction

[0038]Referring to FIG. 2A, a gas lift mandrel 60 is installed on tubing 20 of a wellbore completion. The mandrel 60 is shown with a gas lift valve 100 of the present disclosure installed. As shown here, the gas lift valve 100 is wireline-retrievable, but the teachings of the present disclosure can apply to other types of valves, such as tubing-retrievable valves when used with an appropriate mandrel and tubing running procedures. The gas lift valve 100 includes a variable orifice assembly 150 according to the present disclosure. The variable orifice assembly 150 may be initially in a closed condition, but is configured to open once activated, as discussed later.

[0039]While the variable orifice assembly 150 is in the closed condition, the gas lift valve 100 can be run into the tubing 20 by wireline and can be inserted into the side pocket 65 of the mandrel 60. A latch 109 of the gas lift valve 100 engages a profile 69 in the side pocket 65 to hold the gas lift valve 100 therein. Pac...

Claims

1. A gas lift valve comprising:a housing defining an interior passage having a first port and a second port, the first port being exposed to one of an annulus pressure and a tubing pressure, the second port being exposed to the other of the annulus pressure and the tubing pressure;a piston disposed in the housing, the piston being exposed to an internal pressure in a first portion of the interior passage and being biased by a dome pressure in a second portion of the interior passage the internal pressure being at least associated with the annulus pressure, the piston being movable in first and second axial directions with axial movement in the interior passage at least in response to a pressure differential between the dome pressure and the internal pressure in the interior passage; andan indexing collar disposed in the interior passage and defining an orifice port therein, the indexing collar being rotatably indexed in rotational positions in the interior passage in response to the axial movement of the piston in at least one of the first and second axial directions, alignment of the orifice port with the first port being variable based on the rotational positions of the indexing collar, whereby the orifice port is configured to vary communication between the first port and the second port.2-3. (canceled)4. The gas lift valve of claim 1, wherein the second portion of the interior passage in the housing defines a dome chamber having the dome pressure; and wherein the piston comprises a bellows connected between the piston and the interior passage, the bellows separating the dome chamber from the interior passage having the first port and the second port.

5. The gas lift valve of claim 1, wherein the piston is movable with the axial movement in the first axial direction in response to a first of the pressure differential of the internal pressure over the dome pressure; and wherein the piston is movable with the axial movement in the second axial direction in response to a second of the pressure differential of the dome pressure over the internal pressure.

6. The gas lift valve of claim 1, comprising a biasing element biasing the indexing collar in the second axial direction in the interior passage.

7. The gas lift valve of claim 1, wherein the piston is selectively engageable with the indexing collar, the indexing collar being movable with the axial movement in the first axial direction by the piston engaged with the indexing collar; and wherein the indexing collar defines an internal profile; and wherein the piston comprises a collet disposed on a distal end of the piston, the collet being selectively engageable with the internal profile of the indexing collar.

8. (canceled)9. The gas lift valve of claim 1, wherein the indexing collar moved in response to the axial movement in the first axial direction is rotatable in a first increment of the rotational positions in response to a first indexing engagement between a first intermediate cam on the indexing collar with a first cam in the interior passage.

10. (canceled)11. The gas lift valve of claim 9, wherein one of:the indexing collar is movable in the second axial direction in response to the piston disengaged with the indexing collar, the indexing collar moved in the second axial direction being fixable in the rotational positions in response to a locking engagement between the indexing collar and the interior passage; andthe indexing collar is movable in the second axial direction in response to the piston disengaged with the indexing collar, the indexing collar moved in the second axial direction being rotatable in a second increment of the rotational positions in response to a second indexing engagement between a second intermediate cam on the indexing collar with a second cam in the interior passage.

12. The gas lift valve of claim 1, wherein the interior passage defines a first cam on one side of the first port and defines a second cam on an opposite side of the first port; and wherein the indexing collar has a first intermediate cam and a second intermediate cam.

13. The gas lift valve of claim 12, wherein the first and second cams have an offset from one another, the first and second intermediate cams being configured to alternately engage the first and second cams, the offset of the first and second cams being configured to rotate the indexing collar in incremented rotations in response to the first and second intermediate cams alternately engaged with the first and second cams.

14. The gas lift valve of claim 1, comprising an indexing mechanism arranged between the indexing collar and the interior passage, the indexing mechanism being configured to rotatably index the indexing collar in the rotational positions in the interior passage in response to the axial movement of the piston in the at least one of the first and second axial directions.

15. The gas lift valve of claim 14, wherein the indexing mechanism comprises:a first shoulder disposed in the interior passage and defining first castellations on one side of the first port;a second shoulder disposed in the interior passage and defining second castellations on an opposite side of the first port;a first edge of the inner indexing collar defining first teeth; anda second edge of the indexing collar defining second teeth.

16. (canceled)17. The gas lift valve of claim 15, wherein the first castellations are ramped; and wherein the first teeth are ramped and are configured to index in a first indexing engagement with the first castellations to rotate the indexing collar; and wherein one of:the second castellations are ramped, and the second teeth are ramped and are configured to index in a second indexing engagement with the second castellations to rotate the indexing collar; andthe second teeth of the indexing collar are configured to engage in a locking engagement with the second castellations.

18. (canceled)19. The gas lift valve of claim 14, wherein the indexing mechanism comprises:a slot profile defined on an outer surface of the indexing collar or on an inner surface of the interior passage, the slot profile having resting positions offset from one another; andat least one pin extending from the outer surface or the inner surface and disposed in the slot profile, the at least one pin being configured to ride in the slot profile alternating between the resting positions.

20. The gas lift valve of claim 14, wherein the indexing mechanism comprises:a slot profile defined on one of an outer surface of the indexing collar or on an inner surface of the interior passage and having cammed ridges; andsplines defined on the other of the outer surface or the inner surface and disposed in the slot profile, the splines having cammed ends alternating engaging between the cammed ridges.

21. A gas lift valve comprising:a housing defining an interior passage, the interior passage having a first port and a second port, the first port being exposed to one of an annulus pressure and a tubing pressure, the second port being exposed to the other of the annulus pressure and the tubing pressure, the interior passage defining a first shoulder on one side of the first port and defining a second shoulder on an opposite side of the first port;a piston disposed in the housing, the piston being exposed to an internal pressure in a first portion of the interior passage and being biased by a dome pressure in a second portion of the interior passage the internal pressure being at least associated with the annulus pressure, the piston being movable with axial movement in first and second axial directions in the interior passage at least in response to a pressure differential between the dome pressure and the internal pressure in the interior passage;a collar disposed in the interior passage, the collar defining an internal profile and defining an orifice port therein;a collet disposed on a distal end of the piston, the collet being selectively engageable with the internal profile in the collar, the collet engaged with the internal profile of the collar being configured to move the collar with the axial movement at least in the first axial direction; andan indexing arrangement being configured to rotate the collar in rotational positions in the interior passage at least in response to the collar being moved in the first axial direction, alignment of the orifice port of the collar with the first port of the housing being variable with respect to the rotational positions of the collar, whereby the orifice port is configured to vary communication between the first port and the second port.22-24. (canceled)25. The gas lift valve of claim 21, wherein the indexing arrangement comprises a biasing element biasing the collar in the second axial direction in the interior passage.

26. The gas lift valve of claim 21, wherein the indexing arrangement comprises first and second shoulders defined in the interior passage; and wherein the collar has first and second edges, the collar moved with the axial movement in the at least one of the first and second axial directions being rotatable in an increment of the rotational positions in response respectively to at least one of the first edge being engaged in a first indexing engagement with the first shoulder and the second edge being engaged in a second indexing engagement with the second shoulder.

27. The gas lift valve of claim 26, wherein each of the first and second edges comprises a plurality of ramped teeth disposed circumferentially about the respective edge of the collar; and wherein each of the first and second shoulders comprises a plurality of ramped castellations disposed circumferentially about the respective shoulder.

28. (canceled)29. The gas lift valve of claim 26, wherein:the collar moved in the first and second axial directions is rotatable in the increment in response respectively to the first and second indexing engagements; orthe collar moved in the first axial direction is rotatable in the increment in response to the first indexing engagement, and the collar moved in the first axial direction is fixable in the rotational position in response to a locking engagement between the second edge and shoulder.30-34. (canceled)35. The gas lift valve of claim 21, further comprising a check valve disposed in the interior passage, the check valve being configured to prevent communication of tubing pressure at the second port to the interior passage and being configured to allow communication of the internal pressure to the second port.

36. The gas lift valve of claim 21, wherein the second portion of the interior passage in the housing defines a dome chamber having the dome pressure; and wherein the piston comprises a bellows connected between the piston and the interior passage, the bellows separating the dome chamber from the first port and the second port.

37. The gas lift valve of claim 1, further comprising a check valve disposed in the interior passage, the check valve being configured to prevent communication of tubing pressure at the second port to the interior passage and being configured to allow communication of the interior pressure to the second port.

38. A gas lift valve comprising:a housing defining an interior passage having a first port and a second port, the first port being exposed to one of an annulus pressure and a tubing pressure, the second port being exposed to the other of the annulus pressure and the tubing pressure, the housing defining a dome chamber having a dome pressure;a piston disposed in the housing, the piston comprising a bellows connected between the piston and the interior passage, the bellows separating the dome chamber from the interior passage, the piston being biased by the dome pressure in the dome chamber of the housing, the piston being movable in first and second axial directions with axial movement in the interior passage at least in response to a pressure differential between the dome pressure and an internal pressure in the interior passage; andan indexing collar disposed in the interior passage and defining an orifice port therein, the indexing collar being rotatably indexed in rotational positions in the interior passage in response to the axial movement of the piston in at least one of the first and second axial directions, alignment of the orifice port with the first port being variable based on the rotational positions of the indexing collar.

39. The gas lift valve of claim 38, wherein the indexing collar defines an internal profile; wherein the piston comprises a collet disposed on a distal end of the piston, the collet being selectively engageable with the internal profile in the indexing collar, the collet engaged with the internal profile of the indexing collar being configured to move the indexing collar with the axial movement at least in the first axial direction; and wherein the gas lift valve comprises an indexing mechanism arranged between the indexing collar and the interior passage, the indexing mechanism being configured to rotatably index the indexing collar in the rotational positions in the interior passage at least in response to the indexing collar being moved in the first axial direction.

40. The gas lift valve of claim 39, wherein the indexing mechanism comprises one of:a first portion of the interior passage on one side of the first port being configured to engage in a first camming engagement with the indexing collar, and a second portion of the interior passage on an opposite side of the first port being configured to engage in one of a second camming engagement and a fixed engagement with the indexing collar;a slot profile defined on the indexing collar or the interior passage and having resting positions offset from one another, and at least one pin extending from the interior passage or the indexing collar and being configured to ride in the slot profile alternating between the resting positions; anda slot profile defined on the indexing collar or the interior passage and having cammed ridges, and splines defined on the interior passage or the indexing collar and having cammed ends alternating engaging between the cammed ridges.

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