Patent Publication Number: US-9428977-B2

Title: Multi-stage locking system for selective release of a potential energy force to set a subterranean tool

Description:
FIELD OF THE INVENTION 
     The field of the invention is actuation devices for subterranean tools and more particularly devices that enable selective remote actuation while avoiding wall openings and their associated seals that can present potential leak paths. The device will allow actuation of equipment without a need to have any plug in the tubing against which pressure has to be applied. 
     BACKGROUND OF THE INVENTION 
     Pressure actuated assemblies that are designed to selectively actuate a subterranean tool typically involves a ball seat and a ball that is dropped or pumped to the ball seat and landed. Once the ball is landed internal pressure is built up through a wall opening to a piston housing surrounding the main bore so that a tool can be actuated. Typically a piston receives the internal pressure through a wall port and has an opposite end referenced to annulus pressure. Raising the tubing pressure moves the piston which actuates the tool. In one example of a liner hanger, the piston can move slips and a sealing element to support a liner from a surrounding casing. 
     There can be issues with such a design. The tool can be in a long horizontal run so that it may take the ball a long time to get to the seat without having to be pumped. In a horizontal run the ball may not locate on the seat even with a flowing stream urging the ball to the seat. Wall openings to piston housings can also present potential leak paths if seals deteriorate or fail. 
     Accordingly, an actuation system is needed that can be selectively operated from a remote location to operate a tool at the desired location. In the preferred embodiment an actuation system is described that locks in potential energy with a lock that is disabled to release the potential energy to set the tool. In a preferred application a liner hanger slip system and seal can be set with the device. The lock is defeated with physical movement that is induced with an applied field or with an electromechanical device to name a few preferred options. In one embodiment the field is magnetic and the release is accomplished with a repelling response to a magnet while other locking dogs serve at least in part as a locking key for the potential energy that actuates the tool when ultimately released. Those skilled in the art will better appreciate aspects of the preferred embodiments of the invention from a review of the description of the preferred embodiment and the associated FIGS. while recognizing that the full scope of the invention is to be found in the appended claims. 
     U.S. Publication 2012/0234530 A1 has a locking dog system that is put under load by the potential energy force that will ultimately set the tool. The potentially high force that can be needed to set the tool exerts a high friction force on the locking dog member that can make it hard to move the dog sufficiently to release the stored potential energy force. The objective of the present invention is to control the friction load on the locking dogs that respond to the indirect force such as an applied magnetic field to then allow other dogs that hold the actuating potential energy force to release the setting potential energy force. Doing this reduces or eliminates a sticking situation when trying to use an indirect force of limited quantity to move a lock member being pushed on with a very large actuating force for the associated tool. 
     U.S. Pat. No. 7,703,532 illustrates moving a magnet in position to hold open a flapper in a safety valve in the open position and to reduce its tendency to chatter in the open position. U.S. Publication 2009/0032238 illustrates a magnet used to assist the movement of a flapper in a safety valve to go to an open position by adding to the gravity force of the flapper weight that tends to move it to the open position. Another magnet can be used to urge the flapper to the closed position. U.S. Pat. No. 7,828,066 transmits power through a magnetic shaft coupling. U.S. Pat. No. 3,264,994 shows the use of a magnet on a dart that is pumped past a tool to use the field to trigger tool actuation. U.S. Publication 2010/0126716 illustrates a hard wired system for initiating tool actuation using a magnetic field. Other patents of interest with regard to the present invention are: U.S. Pat. Nos. RE 30,988; 7,703,532; 7,669,663; 7,562,712; 7,604,061; 7,626,393 and 7,413,028. 
     SUMMARY OF THE INVENTION 
     An actuation tool uses a lock that when released allows a moving magnet to move into position to repel another magnet. Alternatively a magnetic field can be triggered in a stationary magnet such as one delivered on wireline, for example, to accomplish tool actuation. The repelling force on the second magnet moves it away from a locking position to allow another lock to retract and release the stored potential energy, where the release of the potential energy creates kinetic energy to drive an actuation assembly to set the tool. In a preferred application the tool can be a liner hanger. The release device can be a selectively energized electromagnet or a solenoid that shifts at least one magnet into alignment with at least one second magnet so as to defeat the second magnet from effectively supporting dogs that retain the potential energy whose movement can set the tool. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an application of the lock in a liner hanger shown in the run in position; 
         FIG. 2  is a section view through  FIG. 1 ; 
         FIG. 3  is another section view through  FIG. 1  and offset 12 degrees from  FIG. 2 ; 
         FIG. 3A  is an enlarged view of the dashed box in  FIG. 3 ; 
         FIG. 4  is another section view through  FIG. 1  and offset 6 degrees from  FIG. 2 ; 
         FIG. 4A  is an enlarged view of the dashed box in  FIG. 4 ; 
         FIG. 5  shows the run in view with the dogs that retain the setting force enabled; 
         FIG. 6  is the view of  FIG. 5  showing the dogs that retain the setting force released to radially retract; 
         FIG. 7  is the view of  FIG. 6  showing the dogs that retain the setting force radially retracted; 
         FIG. 8  is the view of  FIG. 7  with the potential energy released so that the movement of the setting ring sets the slips of the tool; 
         FIG. 9  is a perspective view of a magnetic tool being brought into position for setting the tool; 
         FIG. 10  is the view of  FIG. 9  showing initial movement of dogs moving radially by virtue of the magnetic field to enable subsequent movements to set the tool; 
         FIG. 11  is the view of  FIG. 10  showing movement of a first ring, that disables locking dogs that release the potential energy for setting the tool; 
         FIG. 12  is the view of  FIG. 11  with the potential energy released so that the tool can set. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       FIG. 1  shows an application in a liner hanger but the invention is applicable to subterranean tools in general. The slips  8 , which can also be considered the final controlled element of a subterranean tool that in this case of the preferred embodiment is a liner hanger, are operably connected to ring  5  that has openings  10  into which conforming ends  12  of the slips  8  are located. The mandrel  1  supports springs  7 , which are considered the first potential energy source, at support surfaces  14 . The actuating ring  5  is prevented from moving uphole or in the direction of arrow  16  by dogs  4  that are considered the first detent and are supported for radial extension by fingers  18  that extend from release ring  2 .  FIG. 5  shows a close up view of a finger  18  and the dog  4  showing a cantilevered end  20  that is held out radially by an adjacent finger  18 . The same view in section is shown in  FIG. 2  where one of the fingers  18  is seen holding an adjacent dog  4  radially outwardly to extend beyond surface  22  of the mandrel  1  in such a way that the actuating ring  5  cannot move in the direction of arrow  16  because sloping surface  24  on actuating ring  5  engages sloping surface  26  on the dog  4  such that the upper end  26  of dog  4  abuts surface  28  of groove  30  in mandrel  1 . Thus the force of springs  7  is contained during running in because fingers  18  hold dogs  4  in the  FIG. 3  position effectively preventing movement of actuating ring  5  that sets the slips  8 . 
       FIGS. 9-12  illustrate one setting sequence in a design that has no wall openings in the mandrel  1 . A tool X that is capable of moving the retainer  6 , which is considered the second detent, in a radial direction without direct contact is moved in the downhole direction of arrow  32 . As best seen in  FIG. 2  in the run in position the placement of retainer  6  holds ring  2  in the position where dogs  4  are extended to hold the actuating ring  5  from moving. Radial movement of retainer  6  allows dog release ring  2  to move under the influence of springs  3 , considered to be the second potential energy source. As previously explained, axial movement of dog release ring  2  in the direction of arrow  32  will allow the dogs  4  to move radially toward mandrel  1  as the slot  34  aligns with opposed cantilevered ends  20  as best seen when comparing  FIGS. 5 and 6 .  FIG. 7  shows the dogs  4  fully in the slot  34  so that springs  7  can move the actuating ring  5  in the direction of arrow  16  to extend the slips  8  to effectively set the tool.  FIG. 8  shows the onset of motion of the actuating ring  5  after the dogs  4  are fully retracted. 
     Referring to  FIGS. 4 and 9  it can be seen that retainer  6  is a housing that surrounds a magnet or magnets or other material responsive to the tool X when they are brought in close proximity as shown in  FIG. 10 . As a result the effect of the magnetic field the magnet  36  is repelled in the direction of arrow  38  taking the retainer with it so that the release ring  2  that was held back against the force of springs  3  can now advance axially in the direction of arrow  32  as is best seen when comparing  FIGS. 10 and 11 . Because the dogs  4  have retracted into groove  34  as a result of movement of release ring  2  under the force of springs  3 , the actuating ring  5  can now be biased to move in the direction of arrow  40  to set the slips  8  as shown in  FIG. 12 . The tool X can now be repositioned or removed from the borehole. 
     Referring to  FIG. 4  it can be seen that the retainer  6  is pushed against surface  42  of mandrel  1  by the lower end  44  of the release ring  2  acting under bias from springs  3  that are fairly weak essentially only needing to produce enough force to slide release ring  2  when the retainer  6  is moved radially away from mandrel  1  with tool X. This means that the friction force that has to be overcome between the retainer  6  and the surface  42  is fairly minimal. This is to be contrasted with the design in U.S. Publication 2012/0234530 where the load from the actuating springs that set the tool is held by the equivalent of the retainer  6  which in turn requires a much larger force to be applied to overcome frictional resistance. The required force to overcome friction in the prior tool could be so high that the magnetic field that was used to try to move the retainer was insufficient to initiate the setting process unless the spring force of the actuating springs in that design were reduced. Instead, in the present invention, the friction force against surface  42  is minimized because the source of such a force when trying to move the retainer  6  in the direction of arrow  38  is minimal as its source in springs  3  is minimal and orders of magnitude less than if the actuation springs applied the force as in U.S. Publication 2012/0234530. 
     It should be noted that a leaf spring or equivalent  46  that is schematically illustrated can hold the retainer  6  against mandrel  1  during running in to prevent inadvertent tool actuation. 
     Referring to  FIG. 3  the actuating ring  5  has a tapered leading surface  24  that uses the large force available from springs  7  to cam the dogs  4  into slots  30  as soon as axial movement of release ring  2  enables the dogs  4  to be pushed in radially using surface  24 . The available three from springs  7  is so great as to easily overcome resisting friction forces against surfaces  28 . 
     The present invention can be used to actuate any subterranean tool with a released potential energy source. Although springs  7  are illustrated for that purpose, pressurized fluid or pressure in control lines from the surface or other location can be used. Hydrostatic pressure against an atmospheric chamber can also be deployed. Similarly, alternative sources of potential energy for springs  3  are contemplated. The actuation can be initiated with tool X and employ a magnetic field as explained or other techniques that do not require holes in the wall of mandrel  1  can be employed to move the retainer  6  away from mandrel  1  to get the setting process started. For example, the tool X can flex the wall of mandrel  1  elastically. A cam can lift the retainer  6  in response to a surface signal that is processed locally to drive the cam and raise the retainer  6 . A sealed volume outside the mandrel  1  and below the retainer  6  can be employed to move the retainer  6  radially away from mandrel  1  using well fluid pressure in the annulus or delivered from auxiliary lines from the surface or another location. 
     The use of opposed movement for setting the tool allows for a lightly loaded retainer  6  that can respond to an actuation force that is modest without having to overcome frictional forces of a much higher magnitude such as when the large potential energy force that sets the tool is also retained by the same retainer that has to move to release the setting force. Instead by using opposed movements to set the tool, the generated force to initiate the setting of the tool can be modest such as is needed to overcome friction forces created with springs  3  that only need to be strong enough to move the release ring  2  so that the dogs  4  can drop out of the way to let the tool set. The movement of the actuating ring  5  is in an opposed direction to release ring  2 . This allows the use of tool X using for example a magnetic field to have enough energy to move the retainer  6  while at the same time allowing springs  7  to be as strong as needed. A bi-directional setting sequence allows the separation of the setting function potential energy from the locking mechanism to then permit a much lower force to enable the setting in the form of the actuation tool such as a source of electromagnetic energy. The separation allows the use of lower energy actuation because the components move independently of the actuating ring  5  that sets the tool, which in the case of the preferred embodiment is a liner hanger. 
     The above description is illustrative of the preferred embodiment and many modifications may be made by those skilled in the art without departing from the invention whose scope is to be determined from the literal and equivalent scope of the claims below: