Patent Publication Number: US-9845661-B2

Title: Exercising a well tool

Description:
RELATED APPLICATIONS 
     This application is a continuation of and claims the benefit of priority to U.S. patent application Ser. No. 13/759,257, filed Feb. 5, 2013, which claims the benefit of priority to PCT/US2012/023937, filed Feb. 6, 2012. The contents of these two prior applications are incorporated herein by reference. 
    
    
     BACKGROUND 
     Many well tools operated in response to a hydraulic signal also have provisions for mechanical operation, for example with a shifting tool of a work string or a wire run actuator tool. Such provisions enable contingent mechanical operation of the well tool when the hydraulic operation is impossible or impracticable. For example, a deep set Surface Controlled Subsurface Safety Valve (SCSSV) can sometimes become inoperable due to well debris and can stick in an open, closed or partially closed position when operated during periodic downhole testing. Because of the small operating piston area of the hydraulic actuator and the limited forces produced by the valve&#39;s return spring, it is sometimes not possible to fully operate the SCSSV with the available control line pressure. Wire run and operated exercise tools exist, for example, the Safety Valve Exercise Tool “42TLXXX” made and sold by Halliburton Energy Services, Inc. Such an exercise tool is locked into a profile in the SCSSV flow tube and upward and downward jarring along with control line pressure is used to force movement of the actuator sleeve in the SCSSV. This jarring action is sometimes ineffective because the exercise tool must work against the SCSSV spring, hydraulic piston and the lubricator seal. 
     SUMMARY 
     Certain aspects encompass an exercise tool assembly for operating a downhole tool auxiliary to a primary actuator system of the downhole tool. The exercise tool assembly includes a cylinder mandrel configured to be received in the central bore of the downhole tool. A piston mandrel is in and sealed with the cylinder mandrel. The exercise tool assembly is configured to couple to an actuator sleeve of the downhole tool and to couple to the downhole tool at a location apart from the actuator sleeve. The piston mandrel is responsive to a change in pressure in the central bore to translate relative to the cylinder mandrel and translate the coupling with the actuator sleeve relative to the coupling at the location apart from the actuator sleeve. 
     Certain aspects encompass a method of operating a downhole tool auxiliary to a primary actuator system of the downhole tool. According to the method an exercise tool assembly grips a wall of a central bore of the downhole tool. The exercise tool assembly grips an actuator sleeve of the downhole tool. In response to a pressure change of fluid in the central bore, the exercise tool assembly is operated to shift the actuator sleeve and operate the downhole tool. 
     Certain aspects encompass a well system. A downhole tool is provided in a wellbore of the well system. The downhole tool has a signal responsive actuation system for actuating the downhole tool in response to a remotely generated signal and an actuator sleeve for manually actuating the downhole tool. An exercise tool assembly is received in the downhole tool. The exercise tool assembly grips the downhole tool at a first location on the actuator sleeve and grips the downhole tool at a second location apart from the actuator sleeve. The exercise tool assembly is responsive to pressure in the downhole tool to translate the first location relative to the second location. 
     Other features, objects, and advantages will be apparent from the description and drawings, and from the claims. 
    
    
     
       DESCRIPTION OF DRAWINGS 
         FIG. 1  is a side cross-sectional view of an example well system with an exercise tool assembly. 
         FIGS. 2A-2C  are side cross-sectional views of a Surface Controlled Subsurface Safety Valve with an example exercise tool assembly received in its central bore. The views sequentially depict the operation of the exercise tool assembly.  FIG. 2A  depicts the exercise tool assembly coupled to a running tool after having been initially run and located in the SCSSV.  FIG. 2B  depicts the exercise tool assembly located in the proper position for actuation locked in gripping engagement within the SCSSV.  FIG. 2C  depicts the exercise tool assembly extended having translated the actuator sleeve of the SCSSV downhole to open the safety valve closure.  FIG. 2D  depicts the exercise tool assembly coupled to a pulling tool. The exercise tool assembly is equalized and prepared to be pulled from the SCSSV and the well. 
     
    
    
     Like reference symbols in the various drawings indicate like elements. 
     DETAILED DESCRIPTION 
     The present disclosure encompasses a hydraulically operated exercise tool assembly which can operate a well tool auxiliary to the well tool&#39;s on-board remote actuator system (i.e., primary actuator system), either to supplement the well tool&#39;s actuator system (i.e., both the exercise tool assembly and actuator system being operated to operate the well tool) or to operate the well tool without the actuator system being operated, via the well tool&#39;s provisions for mechanical operation. The exercise tool assembly can be used to cycle the well tool uphole and downhole through its operating states, for example, to cycle the tool&#39;s actuator sleeve both uphole and downhole, repeatedly. In the context of a SCSSV, the exercise tool assembly can open and close a SCSSV one, two, or more times. The exercise tool assembly need not be supported by or even coupled to a wire (e.g., wireline, slickline, e-line, and/or other) or a tubing string (e.g., coiled tubing, jointed tubing and/or other) when operating the well tool, thus enabling the exercise tool assembly to be run into a well on a running tool via wire or tubing, and then the wire slacked or the running tool and wire or tubing string removed from the well. With the wire or tubing removed from the well, the well can be robustly closed in (e.g., by a downhole or surface valve) and the exercise tool assembly can be hydraulically operated to cycle the well tool without needing a rig or wire capable vessel at the well. 
       FIG. 1  depicts an example subsea well system  10  incorporating an exercise tool assembly  12  constructed in accordance with the concepts herein. The well system  10  has a subterranean well bore  14  that extends from a wellhead  16  at the terranean surface  18  into one or more subterranean zones of interest. Here, the well system  10  is a subsea well, so the terranean surface  18  is the sea floor, but the concepts described herein could be equally applied to a surface well system. The wellhead  16  includes one or more valves  20  that can be selectively opened or closed for closing in the well by closing off flow through the wellhead  16 . The wellhead  16  may include other components, such as blow out preventers and/or other components. A completion string  22  including tubing and well tools extends downhole from the wellhead  16 . Among other things, the completion string  22  includes a well tool  24  to be operated by the exercise tool assembly  12 . In certain instances, for example, when the exercise tool assembly  12  is run into the well on a conveyance  30 , such as coiled tubing or wire, the wellhead  16  can further include a lubricator  26  to seal around the tubing or wire and seal the well. 
     The exercise tool assembly  12  is configured to be run into the well bore  14 , into the central interior bore of the completion string  22  and well tool  24 , carried on a running tool  28  that is coupled with the exercise tool assembly  12 . In the example depicted in  FIG. 1 , the running tool  28  and exercise tool assembly  12  are run in a tool string on wireline, but in other instances, the exercise tool assembly  12  and running tool  28  can be run on tubing (coiled and/or jointed). In certain instances, the tool string further includes wireline jars and stem. Running the exercise tool assembly in a tool string on wireline, slickline or the like enables the tool string to be run into the well system  10  with a vessel having wire handling capabilities. Thus, a rig with jointed tubing or coiled tubing handling capabilities is not needed. Such vessels with only wire handling capabilities are typically smaller and more plentiful, and thus less expensive to hire and operate and easier to schedule than a rig with jointed or coiled tubing handling capabilities. 
     When run into the well tool  24 , the exercise tool assembly  12  initially engages to and grips the well tool  24  at an actuator sleeve of the well tool  24  and at a location apart from the actuator sleeve. Then, the running tool  28  is operated (hydraulically, electrically, by mechanical manipulation and/or otherwise) to lock the exercise tool assembly  12  in gripping engagement with the well tool  24 . When the running tool  28  is removed, an equalizing valve of the exercise tool assembly  12  is closed to close off communication of pressure between the central bore of the well tool  24  (as well as the central bore of the exercise tool assembly  12 ) and the exterior of the exercise tool assembly  12 . With the exercise tool assembly  28  in gripping engagement with the well tool  24 , the weight of the exercise tool assembly  28  is supported and the exercise tool assembly  28  is anchored in the well tool  24 . The running tool  28  can be released from the exercise tool assembly  12  and can be removed from the well  10 , along with the remaining tool string and wire (or tubing) the running tool  28  was run in on. Removing the tool string and wire from the well  10  allows the well  10  to be robustly closed-in by the valve  20  at the wellhead  16  for safety. Valves are typically more robust than the seal achieved by a blow-out-preventer sealed around a tubing or lubricator sealed around a wire, and multiple valves can be used to ensure a redundant seals that meet regulatory requirements. In certain instances, the valve  20  can be of a type having a metal to metal, gas tight seal. 
     The exercise tool assembly  12  can be operated to cycle the actuator sleeve of the well tool  24  uphole and downhole, and thus operate the well tool  24  to open and close, as many times as is desired without intervention into the well. For example, the exercise tool assembly  12  can be operated by alternately increasing pressure and decreasing pressure in the central bore of the completion string  22  relative to a specified pressure. In certain examples, the specified pressure is the pressure that the exercise tool assembly  12  was equalized at (i.e., the pressure in the central bore when the equalizing valve of the exercise tool assembly  12  was closed). For example, fluids can be pumped into and released from the central bore via a port in the wellhead  16 . In certain examples of a subsea well, the fluids can be pumped into the well  10  using a subsea remote operated vehicle (ROV) or another remote surface or subsea pump system. As methanol is typically readily available at subsea wells for prevention of hydrates, the fluid pumped into the well, in certain instances, can be methanol and/or other treatment chemicals used in the well completion or production. Still other fluids can be used. In one example, the exercise tool assembly  12  strokes down (i.e., expands) in response to increased pressure in the central bore, thus causing the exercise tool assembly  12  to move the well tool  24  actuator sleeve downhole and operate the well tool  24  one half of a cycle. The exercise tool assembly  12  strokes up (i.e., contracts) in response to decreased pressure in the central bore to retract the well tool  24  sleeve uphole and complete the cycle. In certain instances, the exercise tool assembly  12  can be spring biased to a retracted state to facilitate contracting in response to decreased pressure. In other instances, the exercise tool assembly  12  can be alternately configured to contract upon increases in pressure in the central bore and expand in response to decreased pressure. The actuator system of the well tool  24  (i.e., the system that would normally be operated to operate the well tool  24 ) can, in certain instances, be operated in cooperation with the exercise tool assembly  12  to facilitate cycling the well tool  24 . In other instances, the actuator system of the well tool  24  can be not operated and the well tool  24  cycled by operation of the exercise tool assembly  12  alone. 
     The exercise tool assembly  12  can be removed by running the running tool  28 , or a specific pulling tool, back into completion string  22  on wire and/or tubing and engaging the fishing neck of the exercise tool assembly  12 . Withdrawing the exercise tool assembly  12  releases the engagement and gripping of the exercise tool assembly  12  with the well tool  24 , allowing the exercise tool assembly  12  to be pulled from the well  10 . 
     Turning now to  FIGS. 2A-D , an example exercise tool assembly  200  is shown in half side cross section in connection with an example well tool and running tool, SCSSV  210  and running tool  212 . The example exercise tool assembly  200  can be used as the exercise tool assembly  12 , and like the exercise tool assembly  12 , the example exercise tool assembly  200  can be used in other types of well tools than the specific SCSSV  210  depicted. The exercise tool assembly  200  includes a lock mandrel  244  coupled (threadingly and/or otherwise) to an exercise sub  288 , and an equalizing valve  246  received in the exercise sub  288 . In other instances, the features of the lock mandrel  244  and/or equalizing valve  246  can be integrated into a single tool. Also, although depicted with a specific lock mandrel  244  and equalizing valve  246 , there are other types of lock mandrels and equalizing valves that could be used. 
     The example SCSSV  210  is a primarily hydraulically operated valve configured to remain open in response to a hydraulic signal received through a control line  214  and close when the hydraulic signal at the control line  214  is reduced or ceased. The hydraulic signal is a hydraulic pressure above a specified control pressure. The pressure acts on an actuator piston  216  of the SCSSV  210  to drive the piston  216  downhole (toward the right of  FIG. 2A ) to an actuated position. The piston  216 , in turn, engages an actuator sleeve  218  of the SCSSV  210  and drives the actuator sleeve  218  downhole to its actuated position. The actuator sleeve  218  interacts with the valve closure  220  to open the valve closure  220 , and allow flow through the central bore  226  of the SCSSV  210 , when in the actuated position. In the example depicted, the valve closure  220  is a flapper spring biased closed to seal against flow through the central bore  226 , and the actuator sleeve  218  pushes the flapper open when moved downhole to its actuated position. In other examples, the valve closure  220  can be a ball valve, and the actuator sleeve  218  is coupled to the linkage that rotates the ball. A return spring  222  reacts between a fixed location on the SCSSV housing  224  and the actuator sleeve  218  to bias the actuator sleeve  218  and piston  216  uphole to their respective unactuated positions, thus allowing the SCSSV  210  to default with the valve closure  220  closed. Notably, as a safety valve, the primary actuator system of the SCSSV  210  is the hydraulic actuation system, including the control lines  214  and actuator piston  216 . The example SCSSV  210  has provisions for contingency operation apart from the hydraulic actuation system, for example, if the hydraulic actuation system fails or cannot produce enough force to open the closure  220 . Particularly, the SCSSV  210  includes a key engaging profile  228  in the interior of the actuator sleeve  218  that allows the actuator sleeve  218  to be engaged by keys of a shifting tool deployed in a working string. Once engaged, the shifting tool can be used to manually manipulate the actuator sleeve  218  via the working string and without hydraulically operating the hydraulic actuation system. 
     The exercise tool assembly  200  is depicted in  FIG. 2A  as set in the SCSSV  210  engaged with the SCSSV  210 , and partially locked to the SCSSV  210 . The exercise tool assembly  200  has been carried into the well and into the SCSSV  210  on the running tool  212 , and as will be discussed in more detail below, the pressure uphole and downhole of the exercise tool assembly  200  has been equalized. 
     The running tool  212  depicted is an Otis RO running tool, where OTIS is a registered trademark of Halliburton Energy Services, Inc. However, other, different running tools could be used. 
     The exercise sub  288  includes a cylinder mandrel  230  and a piston mandrel  232  in and sealed with (via seals  234   a  and  234   b ) the interior of the cylinder mandrel  230 . The piston mandrel  232  carries a plurality of exercise keys  236  arrayed around its circumference. The piston mandrel exercise keys  236  are configured to engage and grip the exercise profile  228  of the actuator sleeve  218 . The lock mandrel key retainer  244  carries another set of lock keys  238  arrayed around its circumference and axially spaced from the exercise keys  236 . The lock mandrel keys  238  are configured to engage and grip the lock mandrel profile  240 , a profile provided apart from the actuator sleeve  218 . For example,  FIG. 2A  shows a lock mandrel profile  240  in the wall of the SCSSV housing  224  that is engaged by lock mandrel keys  238 , but the profile  240  could be at another location above the SCSSV  210 . The lock mandrel keys  238  are each spring biased radially outward by springs  243 . The exercise keys  236  are each spring biased radially outward by springs  243 . Being spring biased as such allows the keys  236 ,  238  to slide along the interior of the central bore  226  as the exercise tool assembly  200  is run into the SCSSV  210 , and snap into initial engagement when the exercise tool assembly  200  is fully received in the SCSSV  210  and the lock mandrel keys  238  align with the lock mandrel profile  240 . The keys of the exercise sub  236  are positioned so they will engage and lock into the exercise profile  228  when they shift down. The illustrated lock profile  240  and lock mandrel  238  are configured with a no-go type initial engagement that stops further downhole movement of the exercise tool assembly  200  as it is being received into the SCSSV  210  to precisely position the exercise tool assembly  200  relative to the SCSSV  210 . 
     The lock mandrel  244  internally receives a key expander mandrel  242  that can translate axially within the lock mandrel  244  between a position radially beneath the lock mandrel keys  238  and a position apart from the lock mandrel keys  238 . When positioned radially beneath the lock mandrel keys  238 , the key expander mandrel  242  locks the keys  238  in a radially expanded position. For example, as seen in  FIG. 2A , when the lock mandrel keys  238  are initially positioned aligned with the profile  240 , translating the key expander mandrel  242  radially beneath the lock mandrel keys  238  locks the keys into gripping engagement with the lock mandrel profile  240 . The key expander mandrel  242 , however, is initially held apart from the lock mandrel keys  238  by a shear pin (not shown). The running tool  212  engages the internal fishing neck which attaches to the key expander mandrel  242 . Once the exercise tool assembly  200  is located in position with the lock mandrel keys  238  in the SCSSV  210 , the jars and stem (not shown) are used to jar down on the running tool  212  on the fishing neck, shearing the shear pin and locking the keys of the lock mandrel  238  propped into the lock profile  240 . With the lock mandrel keys  238  locked in gripping engagement with the profile  240 , the exercise tool assembly  200  is locked to the SCSSV  210 , and cannot move uphole or downhole. Thereafter, the tool string and the running tool  212  can be released and withdrawn uphole from the exercise tool assembly  200  and the well. 
     The lock mandrel  244  carries seals  245  around its circumference that are configured to seal with the interior of the central bore  226 . Thus, pressure above the valve closure equalization pressure applied uphole in the central bore  226  is communicated through the lock mandrel  244  and cylinder mandrel  230  to act on the piston mandrel  232  and drive the piston mandrel  232  axially downhole relative to the lock mandrel  244  and mandrel  230 . 
     The equalizing valve  246  has one or more equalizing ports downhole of the seal  245  to communicate the interior and exterior of the cylinder mandrel  230  while the exercise tool assembly  200  is being run into/out of the SCSSV  210  and well. The downhole end of the lock mandrel  244  is open to allow fluid communication through the interior of the lock mandrel  244 . However, the piston mandrel  232  includes a check valve  248  that seals against communication of fluid from uphole of the piston mandrel  232  downhole, and allows communication of fluid from downhole of the piston mandrel  232  uphole of the piston mandrel  232 . The check valve  248  is shown as a ball that is spring biased into a seat, but it could take other forms. The equalizing valve ports  246  and check valve  248  cooperate to allow higher pressure downhole of the exercise tool assembly  200  to equalize uphole of the exercise tool assembly  200  when it is run into the SCSSV  210 , thus allowing the pressure to be equalized uphole and downhole of the exercise tool assembly  200  to a specified pressure. In certain instances, the pressure is equalized at hydrostatic pressure in the well bore. 
     The equalizing valve housing  231  internally receives a sealing sleeve  250  that has two axially spaced apart seals  252  that seal against the interior of the equalizing valve housing  231 . The sealing sleeve  250  can axially translate between a downhole position, where both seals  252  are downhole of the equalizing ports  246  and allow fluid communication through the ports  246 , and an uphole position where the seals  252  bracket the ports  246  and seal against fluid communication through the ports  246 . The sealing sleeve  250  is initially in the downhole position when the exercise tool assembly  200  is run into the well ( FIG. 2A ) and pressure is equalized. The sealing sleeve  250  includes one or more spring fingers  254  that are biased radially outward but held radially inward by the inner wall of the equalizing valve housing  231  to grip the downhole, prong end of the running tool  212 . When the running tool  212  is withdrawn uphole from the exercise tool assembly  200 , the sleeve  250  is translated uphole to seal the ports  246 . The spring fingers  254  are also moved to a larger diameter portion  255  of the equalizing valve housing  231  to allow the spring fingers  254  to expand outward, release from the prong end of the running tool  212  and release the sleeve  250  from the running tool  212  ( FIG. 2B ). The spring fingers  254  then abut the downhole end of the larger diameter portion  255  to retain the sleeve  250  sealing the ports  246 . 
     The piston mandrel  232  is initially fixed to the cylinder mandrel  230  by a shear pin  256  when the exercise tool assembly  200  is run into the well ( FIG. 2A ). With the cylinder mandrel  230  locked into the profile  240 , applying pressure uphole through the central bore  226  drives the piston mandrel  232  downhole and shears the pin  256  to release the piston mandrel  232  from the cylinder mandrel  230  ( FIG. 2B ). 
     The exercise keys  236  are retained in the key retainer sleeve  258  received over and configured to translate axially relative to the piston mandrel  232 . The outer surface of piston mandrel  232  proximate the keys  236  defines a key expander profile  260 . When the piston mandrel  232  is retained to the cylinder mandrel  230  by the shear pin  256  ( FIG. 2A ), the key expander  260  is axially positioned to allow the keys  236  to radially retract. However, when pressure is applied uphole through the central bore  226 , the shear pin  256  is sheared, and the piston mandrel  232  is translated downhole, the key expander  260  is moved to an axial position that locks the keys  236  radially extended into gripping engagement with the actuator sleeve profile  228  ( FIG. 2B ). One or more shear pins  262  are carried by the key retainer sleeve  258  and biased inward by springs  264 . When the piston mandrel  232  translates downhole to lock the keys  236  radially expanded, the shear pin(s)  262  spring inward into a shear pin receptacle  266  of the piston mandrel  232  and fixes the piston carrying sleeve  258  to the piston mandrel  232  with the keys  236  locked radially expanded. Further pressure applied uphole through the central bore  226  drives the piston mandrel  232  further downhole to drive the actuator sleeve  218  downhole. The reaction forces of driving the actuator sleeve  218  downhole are born by the keys  238 . Notably, the piston area presented by the piston mandrel  232  and check valve  248  (i.e., the area within seals  234   a ) is substantially larger than the piston area presented by the actuator pistons  216  of the SCSSV  210 . Therefore, a much larger maximum force is applied to drive the actuator sleeve  218  downhole via pressure applied to the exercise tool assembly  200  than via the same magnitude of pressure applied to the actuator piston  216  of the SCSSV  210 . In certain instances, pressure can be applied to both the exercise tool assembly  200  and the actuator piston  216  of the SCSSV  210  concurrently to maximize the force applied to drive the actuator sleeve  218  downhole. 
     An adjusting nut  270  coupled to the piston mandrel  232  abuts a corresponding limiter shoulder  272  on the cylinder mandrel  230  to limit the downhole translation or stroke of the piston mandrel  232  relative to the cylinder mandrel  230  ( FIG. 2B ). In the figures the adjusting nut  270  is threaded to the exterior of the check valve  248 , so its position can be axially adjusted relative to the piston mandrel  232  to enable adjustment of the stroke. In other instances, the adjusting nut  270  can be coupled to the piston mandrel  232  in a different manner (e.g., on the piston mandrel  232  itself or to another component) and need not be threaded. The adjusting nut  270  enables adjusting the stroke of the exercise tool assembly  200  relative to the stroke of the actuator sleeve  218  (e.g., to be equal, slightly shorter, or other) so that operation of the exercise tool assembly  200  does not over extend and damage the actuator sleeve  218  or SCSSV  210 . 
     A return spring is provided to return the piston mandrel  232  axially uphole relative to the cylinder mandrel  230  when uphole pressure through the central bore  226  is reduced back to the equalization pressure. In  FIG. 2A , the return spring is a fluid type spring defined by chamber  268  between the piston mandrel  232  and cylinder mandrel  230  and sealed by seals  234   a  and  234   b . The chamber  268  can be sealed when the piston mandrel  232  and cylinder mandrel  230  are axially contracted, for example, when pinned by the shear pin  256 . In certain instances, the fluid in the chamber is at atmospheric pressure when the piston mandrel  232  and cylinder mandrel  230  are sealed in the axially contracted state. Thereafter, when the piston mandrel  232  is axially extended from the cylinder mandrel  230  downhole, the chamber  268  is enlarged and a pressure less than atmospheric pressure is created in the chamber  268 . When pressure is released from the central bore  226  and control line  214 , the differential pressure between the chamber pressure versus the hydrostatic pressure forces the piston mandrel  232  back into the cylinder mandrel  230 , and returns the actuator sleeve  218  uphole. In the case of a SCSSV  210 , the return spring  222  of the SCSSV  210  will also assist in pushing the piston mandrel  232  back into the cylinder mandrel  230  and the actuator sleeve  218  uphole. 
     Notably, although described as a fluid spring that operates by reducing pressure within the chamber  268  (i.e., vacuum), the fluid spring could operate on increasing the pressure in the chamber  268 , for example, with the chamber being configured to reduce in size and compress a gas in the chamber when the piston mandrel  232  is axially extended from the cylinder mandrel  230 . Alternatively, or in addition to a fluid spring, a mechanical spring could be used (e.g., coil spring, Belleville washers, and/or another mechanical spring) between the piston mandrel  232  and cylinder mandrel  230 . 
     The operations described above to extend and retract the piston mandrel  232  and actuator sleeve  218  can be repeated once, twice, or as many times as is desired. Further, in the instance of an SCSSV  210 , the valve closure  220  can be pressure tested with pressure downhole of the closure  220 . If there is any leakage past the valve closure  220 , the exercise tool assembly  200  will not retain the pressure, but rather will allow communication of the pressure uphole through the check valve  248 . 
     When it is desired to remove the exercise tool assembly  200 , the tool can be disabled to facilitate removal from the well. To this end, the fluid spring of atmospheric chamber  268  has a relief port  276  in fluid communication with the central bore  226 . The relief port  276  is sealed by a pressure relief plug  274 , such as a rupture disk, pressure relief valve and/or other device, that seals the port  276  until exposed to pressure over a specified pressure. Once over the specified pressure, the pressure relief plug  274  opens ( FIG. 2D ) to allow fluid communication with the interior of the cylinder mandrel  230 , thus disabling the return spring. For example, when it is desired to disable the exercise tool assembly  200 , the specified pressure can be applied through the central bore  226  to open the plug  274 . In certain instances, the specified pressure is selected to be above the expected pressures experienced when operating the exercise tool assembly  200  to cycle the actuator sleeve  218 . 
     A pulling tool  278  ( FIG. 2D ) can be used to equalize the pressure through the equalizing valve  246  and release the lock mandrel keys  238  from gripping engagement with the locking mandrel profile  240 . The pulling tool  278  is run into the lock mandrel  244  to push the equalizing valve  246  to the open position. Upward jarring on the pulling tool  278  releases the lock mandrel keys  238  from the lock profile  240 . The pulling tool  278  is shown as run into/out of the well on wireline, but could be run into/out of the well on tubing. The pulling tool  278  ( FIG. 2D ) can be used to jar the cylinder mandrel  230 , and the piston mandrel  232  with it, uphole relative to the key retainer sleeve  258  and the exercise keys  236 , which are still engaged to the actuator sleeve  218 . The uphole jarring shears the shear pin(s)  262  and releases the piston carrying sleeve  258  from the piston mandrel  232 , allows the exercise keys  236  to be unsupported by the expander mandrel  260 , and allows the exercise keys  236  to be pulled uphole from the actuator sleeve profile  228 . Because the shear pin  262  is sheared by an uphole movement, the actuator sleeve  218  is left in an uphole position. Further uphole translation of the pulling tool  278  withdraws the exercise tool assembly  200  from the SCSSV  210  and from the well. Thereafter, the SCSSV  210  is left for normal operation. 
     A number of embodiments have been described. Nevertheless, it will be understood that various modifications may be made. Accordingly, other embodiments are within the scope of the following claims.