Patent Publication Number: US-10787889-B2

Title: Gas lift valve having shear open mechanism for pressure testing

Description:
BACKGROUND OF THE DISCLOSURE 
     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. 
     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. 
     A typical wireline-retrievable gas lift system  10  is shown in  FIG. 1 . Operators inject compressed gas G into the annulus  22  between a production tubing string  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 . 
     Side pocket mandrels  30  spaced along the production string  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 string  20  and prevent reverse flow from the production string  20  into the annulus  22 . 
     A production packer  14  located on the production string  20  forces the flow of production fluid P from a formation up through the production string  20  instead of up through the annulus  22 . Additionally, the production packer  14  forces the gas flow from the annulus  22  into the production string  20  through the gas lift valves  40 . 
     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 string  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&#39;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 string  20 . As the injected gas I rises to the surface, it helps to lift the production fluid P up the production string  20  to the surface. 
     Gas lift valves  40  have been used for many years to assist production of fluid to the surface. The 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 valve  40  into the tubing string. As differential pressure is reduced on the bellows, the valve mechanism in the valve  40  can close. 
     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&#39;s ports  34 , acting as isolation devices. 
     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. 
     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 
     According to the present disclosure, an apparatus is used for a gas lift valve on tubing in a wellbore. The gas lift valve has a pressure-sensitive valve and a check valve. The pressure-sensitive valve is configured to control communication from an inlet toward an outlet. The inlet can be exposed to one of an annulus pressure and a tubing pressure of the wellbore, and the outlet can be exposed to the other of the annulus pressure and the tubing pressure. 
     For example, the gas lift valve can be configured for a tubing flow application. As such, the inlet would be exposed to the annulus pressure, and the outlet would be exposed to the tubing pressure of the tubing. For its part, the check valve is configured to prevent communication from the outlet toward the inlet. Alternatively, the gas lift valve can be configured for an annulus flow application. As such, the inlet would be exposed to the tubing pressure, and the outlet would be exposed to the annulus pressure. 
     The apparatus comprises a piston, a first connection, and a second connection. The piston is disposed between the check valve and the outlet and is exposed to a pressure differential between the annulus pressure and the tubing pressure. The piston is movable from a closed condition to an opened condition relative to the outlet. 
     The first connection holds the piston in the closed condition and is configured to release hold of the piston in response to a predetermined level of the pressure differential. The second connection connects the piston to the check valve. The second connection with the piston in the first position holds the check valve open, whereas the second connection with the piston in the second position releases the hold of the check valve to close. 
     In one configuration, the piston comprises a piston body and a sleeve body. The piston body is sealed in the valve and is exposed to the pressure differential between the annulus pressure in the valve and the tubing pressure via a tubing port of the valve. The sleeve body is sealed in the valve and is movable from the closed condition to the opened condition relative to the outlet port. The first connection connects the piston body to the sleeve body, and the second connection connects the sleeve body to the check valve. 
     The first connection can include a rod having a first end coupled to the piston body and having a second end coupled to the sleeve body. The rod can be breakable in response to a predetermined load between the first and second ends caused by the annulus pressure greater than the tubing pressure. The second connection can include a wire having a first end affixed to the check valve and a second end affixed to the sleeve body. The sleeve body in the closed condition holds the check valve open with tension of the wire, whereas the sleeve body in the opened condition releases the tension of the wire on the check valve to close. 
     In another configuration, the piston comprises a sleeve body sealed in the valve and exposed to the pressure differential. The sleeve body is movable from the closed condition to the opened condition relative to the outlet. The first connection connects the sleeve body to a fixed portion of the valve, and the second connection connects the sleeve body to the check valve. 
     Again, the first connection can include a rod having a first end coupled to the sleeve body and having a second end coupled to the fixed portion of the valve. The rod can be breakable in response to a predetermined load between the first and second ends caused by the tubing pressure greater than the annulus pressure. Also, the second connection can include a wire having a first end affixed to the check valve and a second end affixed to the sleeve body. The sleeve body in the closed condition holds the check valve open with tension of the wire, whereas the sleeve body in the opened condition releases the tension of the wire on the check valve to close. 
     In a number of variations, the check valve can include a dart body biased with a biasing element toward a seat in the valve. The piston can include a lock locking the piston in the opened condition once moved. For example, the lock can include a collet disposed on the piston engageable with a shoulder defined in the valve. 
     In additional variations, the piston can include seals sealing off the outlet with the piston in the closed condition. The piston can include an aperture communicating an interior of the piston outside the piston, the aperture being misaligned from the outlet with the piston in the closed condition and being aligned with the outlet with the piston in the opened condition. The piston can include a biasing element biasing the piston from the closed condition toward the opened condition. 
     The apparatus can further comprise a housing having the piston, the first connection, and the second connection. The housing can be integral to the gas lift valve or can be separately affixable to the gas lift valve. 
     According to the present disclosure, an apparatus is used on tubing in a wellbore. The apparatus comprises a gas lift valve disposed on the tubing and having an inlet and an outlet. The inlet can be exposed to one of an annulus pressure and a tubing pressure of the wellbore, and the outlet can be exposed to the other of the annulus pressure and the tubing pressure. For example, the gas lift valve can be configured for a tubing flow application. As such, the inlet would be exposed to the annulus pressure, and the outlet would be exposed to the tubing pressure of the tubing. 
     A pressure-sensitive valve disposed in the gas lift valve is configured to control communication from the inlet toward the outlet, and a check valve disposed in the gas lift valve is configured to prevent communication from the outlet toward the inlet. 
     A piston is disposed in the gas lift valve between the check valve and the outlet and is exposed to a pressure differential between the annulus pressure and the tubing pressure. The piston is movable from a closed condition to an opened condition relative to the outlet port. 
     The first connection holds the piston in the closed condition and is configured to release hold of the piston in response to a first predetermined level of the pressure differential. The second connection connects the piston to the check valve. The second connection with the piston in the first position holds the check valve open, whereas the second connection with the piston in the second position releases the hold of the check valve to close. 
     The piston, the first connection, and the second connection can have any of the previously described features. Again, the first connection can be configured to release the hold of the piston in response to the first predetermined level of the annulus pressure greater than the tubing pressure, or the first connection can be configured to release the hold of the piston in response to the first predetermined level of the tubing pressure greater than the annulus pressure. 
     The apparatus can further include a plurality of the gas lift valve disposed on the tubing. In fact, the apparatus can even further include a shearable orifice disposed on the tubing downhole of the gas lift valves. The shearable orifice is configured to open in response to a second predetermined level greater than the first predetermined level. 
     The present disclosure discloses a method for gas lift in a completion string disposed in a wellbore. A gas lift valve having an inlet and an outlet is configured by holding a piston in the gas lift valve with a first hold in a first closed condition relative to the outlet and holding a check valve in the gas lift valve with a second hold in a second opened condition between the inlet and the outlet. The gas lift valve is installed on the completion string disposed in the wellbore. The inlet can be exposed to one of an annulus pressure and a tubing pressure of the wellbore, and the outlet can be exposed to the other of the annulus pressure and the tubing pressure. For example, the gas lift valve can be configured for a tubing flow application. As such, the inlet would be exposed to the annulus pressure, and the outlet would be exposed to the tubing pressure of the tubing. 
     The method comprises testing pressure integrity of the completion by alternatingly increasing a pressure differential (i) between the tubing pressure relative to the annulus pressure and (ii) between the annulus pressure relative to the tubing pressure. The gas lift valve are actuated for operation after testing the pressure integrity by: releasing the first hold on the piston to move from the first closed condition toward a first opened condition relative to the outlet by increasing the pressure differential beyond a predetermined limit of the first hold; and releasing, in response to the movement of the piston, the second hold of the check valve to move from the second opened condition toward a second closed position between the inlet and outlet. 
     Installing the gas lift valve on the completion string disposed in the wellbore can comprise deploying the gas lift valve with wireline, or deploying the gas lift valve on tubing. 
     Testing the pressure integrity of the completion can comprise first increasing the tubing pressure relative to the annulus pressure followed by increasing the annulus pressure relative to the tubing pressure. Accordingly, actuating the gas lift valve can comprise releasing a temporary connection to the piston by increasing the pressure differential of the annulus pressure relative to the tubing pressure beyond the predetermined limit for releasing the temporary connection. 
     Testing the pressure integrity of the completion can comprise first increasing the annulus pressure relative to the tubing pressure followed by increasing the tubing pressure relative to the annulus pressure. Accordingly, actuating the gas lift valve can comprise releasing a temporary connection to the piston by increasing the pressure differential of the tubing pressure relative to the annulus pressure beyond the predetermined limit for releasing the temporary connection. 
     The foregoing summary is not intended to summarize each potential embodiment or every aspect of the present disclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates a conventional gas lift system. 
         FIGS. 2A-2B  illustrate a gas lift mandrel without and with a gas lift valve of the present disclosure installed. 
         FIG. 2C  illustrates a completion having gas lift valves according to the present disclosure. 
         FIG. 3  illustrates a gas lift valve having a first activation assembly according to the present disclosure. 
         FIGS. 4A-4B  illustrate details of the first activation assembly during stages of operation. 
         FIG. 5  illustrates a gas lift valve having a second activation assembly according to the present disclosure. 
         FIGS. 6A-6B  illustrate details of the second activation assembly during stages of operation. 
     
    
    
     DETAILED DESCRIPTION OF THE DISCLOSURE 
     Referring to  FIGS. 2A-2B , a gas lift mandrel  60  is installed on a completion string  20  of a wellbore completion. The mandrel  60  is shown without and 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 an activation assembly  200  according to the present disclosure. The activation assembly  200  is initially in a closed condition, but is configured to open once activated, as discussed later. 
     While the activation assembly  200  is in the closed condition, the valve  100  can be run into the tubing sting  20  by wireline and can be inserted into the side pocket  64  of the mandrel  60 . A latch  101  of the valve  100  engages a profile  65  in the side pocket  64  to hold the valve  100  therein. Packing seals  114   a - b  on the valve  100  isolate fluid communication between a port  66  on the mandrel  60  and a valve port  116  on the valve  100 . 
     The valve  100  with the activation assembly  200  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 . As an alternative, the valve  100  with the activation assembly  200  can be used in 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 disclosed valve  100  and the activation assembly  200  are essentially reversed, and a different form of gas lift mandrel may be used. In general, the inlet of the gas lift valve  100  is exposed to the tubing  20  instead of the annulus  22 , while the outlet of the gas lift valve  100  is exposed to the annulus  22  instead of the tubing  20 . The activation assembly  200  operates with the pressure differential between the inlet and outlet to configure the active opening of the valve  100 . 
     Instead of being conventional, the gas lift valve  100  is configured to remain closed during installation and during initial testing of the completion. Therefore, once the valve  100  is installed, the activation assembly  200  keeps the valve  100  closed so pressure testing can be performed. For example, the tubing pressure T P  can be increased in the tubing string  20  to test the tubing&#39;s integrity, and the annulus pressure T P  can be increased to test the casing&#39;s integrity. 
     After testing is completed, the valve  100  can be opened when ready to inject gas through the side pocket mandrel  60  and the valve  100  for entry into the tubing  20  of the completion string. In particular, the gas lift valve  100  is configured to open at a predetermined pressure so the 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&#39;s integrity as required in conventional practice. To achieve the configured opening of the valve  100 , the valve  100  includes the activation assembly  200  to control the initial activation of the gas lift valve  100 . Details of the activation assembly  200  are discussed later. 
     An example completion assembly  50  is shown in  FIG. 2C  having multiple gas lift valves  100  installed on a completion string  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 completion string  20 , and each of the valves  100  has an activation assembly  200  to control the initial activation of the gas lift valve  100 . 
     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 activation assembly  200  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. 
     The activation assemblies  200  allow the casing  24 , tubing string  20 , and other components (e.g., packers) in the well completion  50  to be tested. Then, once activated open, the open assemblies  200  allows gas lift operations to proceed without wireline intervention. Different configurations can be used for the activation. 
     In one configuration, the activation assemblies  200  of the valves  100  are configured to open after testing in response to increased annulus pressure A P  in the annulus  22 . As used herein, “annulus pressure” A P  refers to the pressure in the annulus  22  between the tubing  20  and the wellbore casing  24 . By contrast, “tubing pressure” T P  refers to the pressure in the tubing of the completion string  20  in the wellbore. 
     During testing in this configuration, 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 valves  100 . Operators first perform a tubing test by increasing the tubing pressure T P  to a set test pressure. This tests the integrity of the tubing of the completion string  20 . The operators then bleed off the tubing pressure T P . 
     At this point, operators increase the annulus pressure A P  to apply a set test pressure to the annulus  22  from the surface. This increase in annulus pressure A P  tests packers (not shown) and the casing  24  of the completion  50  by creating a pressure differential between the casing  24  and the tubing  20 . 
     With the casing&#39;s integrity tested, the annulus pressure A P  is then increased to a first predetermined level above the set test pressure to open the activation assemblies  200  of the gas lift valves  100 . The annulus pressure A P  is then increased even further to a second, higher predetermined level to open the shearable orifice valve  70 . 
     Once the annulus pressure A P  reaches the opening pressure differential of the shearable orifice valve  70 , the annulus and tubing pressures A P , T P  throughout the wellbore will equalize. With the pressures A P , T P  then equalized, the gas lift valves  100  are now in open conditions and ready for gas injection operations. 
     In another configuration, the activation assemblies  200  of the gas lift valves  100  are configured to open after testing in response to increased tubing pressure T P . (This installation may not use the shearable orifice valve  70  on the completion  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 valves  100 . Operators first perform a casing integrity test by increasing the annulus pressure A P  from the surface to a set test pressure. This increase in annulus pressure A P  tests any packers and tests the casing  24  of the completion  50  by creating a pressure differential in the annulus  22  relative to the tubing  20 . The annulus pressure A P  is then bled off. 
     Operators then increase the tubing pressure T P  to a predetermined level that opens the activation assemblies  200  of the gas lift valves  100 . Although the valves  100  are now open, certain check valves (e.g., check valve  160  in  FIGS. 3 and 4A-4B ) in the gas lift valves  100  will close and prevent reverse flow of pressure from the tubing  20  to the annulus  22 . The operators now test the tubing integrity by increasing the tubing pressure T P  to a set test level. The tubing pressure T P  is then bled off, and the gas lift valves&#39; activation devices  200  are now in opened conditions and ready for gas injection. 
     Having an understanding of how an activation assembly  200  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 activation assembly  200 . 
     Referring to  FIG. 3 , a gas lift valve  100  having an activation assembly  200  according to a first configuration is shown in cross-section. As shown, the valve  100  is an unloading-type of gas lift valve, and the activation assembly  200  is configured to open the valve  100  in response to an increased annulus pressure (i.e., the pressure that can enter the valve  100  through its injection ports  116 ). 
     The valve  100  includes a housing  110  having packing stacks  114   a - b  disposed thereabout and having the activation assembly  200  disposed toward the valve&#39;s outlet side. The packing stacks  114   a - b  provide a seal that isolates the annulus and tubing pressures when installed in a typical side-pocket gas lift mandrel, such as the mandrel  60  of  FIGS. 2A-2C . In this way, the valve  100  of  FIG. 3  run into the mandrel ( 60 ) is exposed to annular pressure through the injection ports  116 . Thus, when the term “annular pressure” is used in reference to the valve  100 , it means the pressure communicated inside the valve  100 . Reference to tubing pressure, however, refers to the pressure in the completion string to which the outlet of the valve  100  is exposed. 
     Internally, the valve  100  uses a pressure-sensitive valve mechanism to control gas injection. In particular, the valve  100  has a dome chamber  120  and a bellows  135  that bias a valve piston  130  in the valve  100  to control the flow of injected gas entering from the valve port  116  to an injection passage  115  inside the valve  100 . The dome chamber  120  holds a compressed gas, typically nitrogen, which is filled through a port  113  in a top member  112 . This port  113  typically has a core valve (not shown) for filing the chamber  120  and typically has an additional tail plug (not shown) installed during assembly. (Various other components of the valve  100 , such as a latch connected to the top end, are not shown, but would be present, as one skilled in the art would be appreciated.) 
     The bellows  135  is disposed on the valve piston  130  in an ancillary chamber  124  separated from the dome chamber  120  by a chamber seat  122 . The bellows  135  separates the compressed gas in the dome chamber  120  from communicating with the valve port  116  and the injection passage  115  so pressure can be maintained in the chamber  120 . Accordingly, the valve  100  uses this bellows  135  as the membrane between the dome chamber  120  and the annulus injection pressure that opens the valve  100 . 
     Looking at the valve piston  130  in more detail, the valve piston  130  can move between opened and closed conditions in the valve  100 . Opposite the bellows  135 , the valve piston  130  has a distal end  140  that moves relative to an inner seat  150  of the housing  110 . The piston&#39;s distal end  140  has a valve head  142 , which can be spherical in shape to engage the seat  150 . In controlling the flow of injected gas, the valve head  142  on the piston&#39;s distal end  140  engages or disengages the seat  150  to close and open communication from the valve port  116  to the injection passage  115 . 
     To prevent reverse flow from the tubing to the annulus through the valve  100 , a check valve  160  is used at the injection passage  115  of the valve  100 . As is typical, the check valve  160  can be a dart valve with ports  162 . A spring  166  biases the check valve  160  toward a seat  164 , which may have an elastomeric component and a retainer, although other types of seals could be used. 
     Rather than having a conventional outlet for passage of injected gas directly out of the valve  100  from the injection passage  115  to a completion string (not shown), the valve  100  of  FIG. 3  includes the activation assembly  200  installed on the outlet end of the valve  100  for controlling initial fluid communication from the inject passage  115  out of the valve  100 . The activation assembly  200  modifies the initial operation of the valve  100  in a manner described latter. 
     In general, the activation assembly  200  can be attached/threaded to the end of the gas lift valve  100  in place of a conventional nose. As will be appreciated, the activation assembly  200  can be adapted to fit to standard gas lift valves and to be used in standard gas lift mandrels. For example, the activation assembly  200  can be a module threaded onto a packing housing component  170  of the gas lift valve  100 . As discussed in more detail later, the activation assembly  200  is configured to remain initially closed for completion integrity testing and is configured to open at a predetermined pressure after the integrity tests have been completed so the valve  100  can be opened for gas injection. 
     In regular operation, however, injected gas passing into the valve  100  through the injection ports  116  above an injection pressure can overcome the bias of the valve piston  130 . The injected gas can pass into the injection passage  115  when the valve head  142  is distanced opened from the seat  150 . The injected gas can then overcome the bias of the reverse check valve  160  and can exit injection ports  204  to enter the completion tubing for the gas lift operation. 
     Before such regular operation can be performed, however, the activation assembly  200  that modifies the initial operation of the valve  100  must first be opened. Detailed views of the activation assembly  200  are shown in a closed condition of  FIG. 4A  and in an opened condition of  FIG. 4B . (The piston&#39;s stem end  140  is not depicted with any particular operational position in  FIGS. 4A-4B  and is merely depicted in a given position for illustrative purposes. As will be appreciated, the piston&#39;s stem end  140  will move opened and closed depending on the piston&#39;s exposure to annular pressure relative to the dome pressure in the piston&#39;s chamber.) 
     The activation assembly  200  includes a piston housing  202  affixed to the packing housing  170  of the valve  100 . In fact, the piston housing  202  may retain the lower packing stack  114   b  on the packing housing  170 . The piston housing  202  has outlet ports  204  communicating the interior of the housing  202  out of the assembly  200  for injection of gas from the valve  100  to the completion string. The piston housing  202  also has a nose  206  affixed on its end having a tubing pressure port  208 . 
     Internally, the housing  202  contains a piston sleeve or sleeve body  210  movable in the housing  202  from a closed condition (with openings  214  unaligned with the outlet ports  204  as shown in  FIG. 4A ) to an opened condition (with openings  214  aligned with the outlet ports  204  as shown in  FIG. 4B ). The piston sleeve  210  includes seals  213  sealing off the outlet ports  204  when the sleeve  210  is in the closed condition of  FIG. 4A . The piston sleeve  210  also includes a collet  216  or other form of lock for engaging a lock profile either in the piston housing  202  or elsewhere, such as in a lock profile  176  in the packing housing  170  as shown in  FIGS. 4A-4B . 
     A spring  218  biases the piston sleeve  210  from the closed condition ( FIG. 4A ) to the opened condition ( FIG. 4B ), but a temporary connection  230  affixed to an activation piston or piston body  230  in the assembly  200  prevents the biased movement of the piston sleeve  210 . (The temporary connection  230  is shown here as a fracture or shear rod. As will be appreciated, the temporary connection  230  can use other shearable or breakable connections.) 
     As shown, the piston sleeve  210  sealed in the housing  202  with the seals  213  is exposed to a pressure differential between annulus pressure (via piston housing  202 ) and tubing pressure (via outlet ports  204 ). As also shown, the activation piston  220  sealed in the nose  206  with seals  223  is exposed to a pressure differential between annulus pressure (via piston housing  202 ) and tubing pressure (via tubing pressure port  208 ). The fracture rod  230  has a division or breakable portion  235  configured to break/fracture under a predetermined load caused by the pressure differential (and the added bias of the spring  218 ). 
     Once the valve  100  is installed and before regular operation can commence, pressure integrity tests can be performed as described above. With the assembly  200  in its initial condition as in  FIG. 4A , for example, the tubing integrity is tested first. Pressure in the tubing of the completion is increased to a predetermined test pressure while the piston sleeve  210  remains held in its closed condition. The differential pressure between the tubing and annulus pressures (A P , T P ) act on the effective area between the lower and upper seals  213  (e.g., O-rings) on the piston sleeve  210 . The differential pressure also acts on the activation piston  220 , but the assembly  200  does not shear open during this phase of testing. After the tubing test is done, the assembly  200  remains in the closed position. 
     The next step is to pressure test the casing annulus to a first predetermined pressure. This allows the differential between the annulus and tubing pressures (A P , T P ) to act on the full area of the lower piston  220 . Once the casing is tested to the predetermined pressure, the assembly  200  is activated by increasing the pressure in the valve  100 , which is the annulus pressure of the completion. At the surface, for example, an operator increases the pressure in the annulus around the completion string, but not within the completion string. The annulus pressure (A P ) is increased to a predetermined breaking pressure of the fracture rod  230 . 
     In particular, the increasing annulus pressure A P  can pass through the injection ports  116 , through the open piston  130 , past the open check valve  160 , and into the activation assembly  200 . Meanwhile, the sleeve  210  in the assembly&#39;s piston housing  202  is held closed by the fracture rod  230  coupled to the activation piston  220 . For its part, the activation piston  220  is exposed on its uphole-side to the increasing annulus pressure (A P ) inside the piston housing  202  and is exposed on its downhole-side via the tubing port  208  to the lower tubing pressure (T P ) present in the completion string. 
     By increasing the annular pressure (A P ) relative to the tubing pressure (T P ), the activation piston  220  is pushed downward with respect to the other parts of the valve  100 . When the force pushing on the piston  220  is great enough, the fracture rod  230  is stretched to failure at its breaking point  235 , causing failure of the fracture rod  230 . When the casing pressure is bled off, the spring  218  inside the piston housing  202  is then able to push the inner sleeve  210  so that the openings  214  in the sleeve  210  align with the ports  204  in the piston housing  210 . At this point, the valve  100  is in fluid communication, though the side pocket mandrel, with the inside of the completion string. 
     As the wellbore equalizes, however, a string or wire  240  connected to the piston sleeve  210  and the check valve  160  holds the check valve  160  momentarily in the open position, allowing the annulus pressure (A P ) to evacuate the area between the check valve  160  and the lower piston sleeve  210 . This function is desired because pressure trapped in the area between the check valve  160  and the piston housing  170  may act on the larger net force of the piston sealing area and prevent the piston sleeve  210  from shifting to the open position. 
     Once the wellbore equalizes, the spring  218  forces the piston sleeve  210  to the opened condition as shown in  FIG. 4B , allowing the collets  216  to lock into the mating shoulder  176  in the packing housing  170 . After the piston sleeve  210  is shifted, the slack in the wire  240  allows the check valve  160  to then function normally as a spring-loaded, one-way valve. 
     With the piston sleeve  210  in the locked and opened condition as shown in  FIG. 4B , the flow passages  214 ,  204  are aligned in the piston sleeve  210  and the housing  202  allowing for passage of injected gas. In this way, lift gas can enter the valve  100  from the casing via ports  116  to the tubing via ports  204 , thereby allowing the unloading and producing process to begin without wireline intervention. 
     Although a shear or fracture rod  230  is disclosed, it is possible to use other types of shearable or breakable connections. For example, although the rod  230  is configured to break in response to a longitudinal load, shear pins, screws, or other temporary connections could be used and configured to break due to a lateral or shear load. 
     The interconnecting wire  240  can be intended to remain inside the valve  100  during operations, as long as the wire  240  does not interfere with the operation of the check valve  160  or the flow of injection gas out of the valve  100 . Alternatively, the wire  240  can be composed of a material that is degradable, dissolvable, or disintegrable over time in response to certain environmental conditions. For example, the wire  240  can be composed of a reactive metal alloy, such as an aluminum-based alloy or a magnesium-based alloy, or can be composed of a degradable plastic material, such as polyglycolic acid (PGA), polylactic acid (PLA), or the like. 
     Although described above as a wire  240  using tension and slack to temporarily hold the check valve  160  open, other forms of connection can connect the piston sleeve  210  to the check valve  160  to hold the check valve  160  open and then release the hold of the check valve  160 . For example, the connection  240  can be a stiff rod of a given length holding the check valve  160  open as long as the piston sleeve  210  is closed. Shifting of the piston sleeve  210  open can allow the check valve  160  to open, but the difference in displacement between the two can break the stiff rod  240  in one or more places. The broken rod  240  can remain in the valve  100  or can be composed of a material that is degradable, dissolvable, or disintegrable. These and other forms of connection  240  can be used between the piston sleeve  210  and check valve  160 . 
     Referring to  FIG. 5 , a gas lift valve  100  having an activation assembly  200  according to a second configuration is shown in cross-section. The valve  100  is similar to that disclosed above with respect to  FIGS. 3 and 4A-4B  so that like reference numerals are used for similar components. 
     As before, the valve  100  in  FIG. 5  is an unloading-type of gas lift valve. The valve  100  installs in a typical gas lift mandrel, and the packing stacks  114   a - b  provide a seal that isolates the annulus and tubing pressures. The valve  100  includes a housing  110  having packing stacks  114   a - b  disposed thereabout and having the activation assembly  200  disposed toward the valve&#39;s outlet side. The packing stacks  114   a - b  provide a seal that isolates the annulus and tubing pressures when installed in a typical side-pocket gas lift mandrel, such as the mandrel  60  of  FIGS. 2A-2C . 
     The activation assembly  200  is installed on the outlet end of the valve  100  for controlling initial fluid communication from the inject passage  115  out of the valve  100 . Rather than being configured to open in response to an increased annulus pressure (La, the pressure that can enter the valve  100  through its injection ports  116 ), the activation assembly  200  of  FIG. 5  is configured to open the valve  100  in response to an increased tubing pressure (i.e., the pressure to which the outlet of the valve  100  is exposed). 
     Detailed views of the activation assembly  200  are shown in a closed condition of  FIG. 6A  and in an opened condition of  FIG. 6B . (The piston&#39;s stem end  140  is not depicted with any particular operational position in  FIGS. 6A-6B  and is merely depicted in a given position for illustrative purposes. As will be appreciated, the piston&#39;s stem end  140  will move opened and closed depending on the piston&#39;s exposure to pressure relative to the dome pressure in the piston&#39;s chamber.) 
     The activation assembly  200  includes a piston housing  202  affixed to the packing housing  170  of the valve  100 . The piston housing  202  has outlet ports  204  communicating the interior of the housing  202  out of the assembly  200  for injection of gas from the valve to the tubing of a completion. The piston housing  202  also has a closed nose  206  affixed on its end. 
     Internally, the housing  202  contains a piston sleeve or sleeve body  210  movable in the housing  202  from a closed condition (with openings  214  unaligned with the outlet ports  204  as shown in  FIG. 6A ) to an opened condition (with openings  214  aligned with the outlet ports  204  as shown in  FIG. 6B ). The piston sleeve  210  includes seals  213  sealing off the outlet ports  204  when the sleeve  210  is in the closed position of  FIG. 6A . The piston sleeve  210  also includes a collet  216  or other form of lock for engaging a lock profile either in the piston housing  202  or elsewhere, such as in the lock profile  176  in the packing housing  170  as shown in  FIGS. 6A-6B . 
     A spring  218  biases the piston sleeve  210  from the closed condition ( FIG. 6A ) to the opened condition ( FIG. 6B ), but a temporary connection  230  (e.g., a fracture rod) affixed to the housing  202  via an anchor  250  prevents the biased movement of the piston sleeve  210 . As shown, the piston sleeve  210  sealed in the housing  202  with seals  213  is exposed to a pressure differential between annulus pressure (via piston housing  202 ) and tubing pressure (via out ports  204 ). The fracture rod  230  has a division or breakable portion  235  configured to break/fracture under a predetermined load caused by the pressure differential (and the added bias of the spring  218 ). 
     Once the valve  100  is installed and before regular operation can commence, pressure integrity tests can be performed as described above. With the assembly  200  in its initial condition as in  FIG. 6A , for example, the casing integrity is tested first. Pressure is applied to the casing annulus of the well for testing. The force from the annulus pressure (A P ) acts on the piston sleeve  210 , which will hold the piston sleeve  210  in the closed position of  FIG. 6A . 
     Once the annulus pressure test is completed, the annulus pressure (A P ) is released. As the annulus pressure (A P ) is released, the connected string or wire  240  holds the spring loaded check valve  160  in the open position, thereby allowing the pressure between the check valve  160  and the nose  206  of the assembly  200  to be evacuated. This function is desired because pressure trapped in the area between the check valve  160  and the nose  206  may act on the larger net force of the piston sealing area (upper and lower seals  213 ) and prevent the piston sleeve  210  from opening during the tubing shear operation discussed below. 
     After the casing pressure test, the next step is to test the tubing integrity. The tubing pressure (T P ) is increased to a test level to test the integrity of the tubing of the completion. The fracture rod  230  can be configured to break at a pressure differential higher or lower than the planned tubing test. Either way, the increased tubing pressure can reach the breaking pressure of the fracture rod  230 . 
     In a completion of multiple gas lift valves, all the activation assemblies  200  can designed to open at relatively the same differential pressure. However, as each fracture rod  230  breaks, the piston sleeve  210  travels in the upward position. As this occurs, the tension of the connecting wire  240  is released and allows the check valve  160  to travel to the closed position. Because the check valves  160  shift to the closed position after each individual assembly  200  shears, the tubing pressure can be increased at some value above the designed shear value. This can help insure all the assemblies  200  of the multiple gas lift valves  100  are shifted in the open position. 
     After the tubing shear operation is complete, the piston sleeve  210  shifts in the upward position allowing the piston ports  214  to be aligned with the outlet ports  204  on the housing  202  and thereby allow for passage of injected gas. The piston sleeve  210  is held in the open condition by collets  216  that interlock in the mating shoulder  176  in the packing housing  170 . 
     After the piston sleeve  210  is shifted, the slack in the wire  240  allows the check valve  160  to function normally as a spring-loaded one-way valve. Accordingly, the check valve  160  can prevent the increased tubing pressure T P  from communicating out of the gas lift valve  100  so further testing of the tubing integrity can be performed. After the above operations, the gas lift valve  100  is ready for regular operation in which lift gas can enter the valve  100  from casing to tubing via port  116  to the tubing via ports  204 , thereby allowing the unloading and producing process to begin without wireline intervention. 
     Although a shear or fracture rod  230  is disclosed, it is possible to use other types of shearable or breakable connections. For example, although the rod  230  is configured to break in response to a longitudinal load, shear pins, screws, or other temporary connections could be used and configured to break due to a lateral or shear load. 
     Again, the interconnecting wire  240  can be intended to remain inside the valve  100  during operations, or it can be composed of a material that is degradable, dissolvable, or disintegrable over time in response to certain environmental conditions. Moreover, other forms of connection  240  can connect the piston sleeve  210  to the check valve  160  to hold the check valve  160  open and then release the hold of the check valve  160 . 
     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. 
     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.