Patent Publication Number: US-11643892-B2

Title: Wellbore apparatus for setting a downhole tool

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This Application is a Division of application Ser. No. 16/270,426, filed on Feb. 7, 2019, which application is incorporated herein by reference in its entirety. 
    
    
     BACKGROUND 
     Field 
     Embodiments described herein generally relate to a wellbore apparatus for setting a downhole tool. More particularly, the embodiments relate to an apparatus and methods for setting a packer downhole. 
     Description of the Related Art 
     Downhole operations are often accomplished with multiple tools on a single work string. Depending on the operation required, the tools are operated in a predetermined sequence. In some instances, it is necessary to ensure one tool does not operate prematurely. There is a need for a downhole mechanism to prevent inadvertent or premature operation of a tool. More specifically, there is a need to prevent inadvertent or premature setting of a downhole packer. 
     SUMMARY 
     The present disclosure generally relates to a locking system for a downhole tool comprising a first portion having a plurality of displaceable members, a second portion disposed around the first portion; a locked position wherein axial movement between the members is prevented; and an unlocked position wherein axial movement between the members is permitted. In one embodiment, the invention includes a downhole tool comprising a set of slips for maintaining the tool in an axial location in a wellbore. The slips are flow-actuated initially and then maintained in a set position due to a first upward force applied to the tool in the wellbore. A packer for sealing an annular area around the tool includes a locking system actuated by an additional upward force applied to the tool in the wellbore. In one embodiment, the tool is used in connection with a cutting tool to sever and remove a section of a tubular string lining the wellbore. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       So that the manner in which the above recited features of the present disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this disclosure and are therefore not to be considered limiting of its scope, for the disclosure may admit to other equally effective embodiments. 
         FIG.  1    is a front view of a tool according to one embodiment of the invention. 
         FIG.  2    is a section view of the tool of  FIG.  1   . 
         FIG.  3 A  is an exploded view showing different parts of the tool. 
         FIG.  3 B  is an exploded view showing different parts of the tool. 
         FIG.  3 C  is an exploded view showing different parts of the tool. 
         FIG.  3 D  is an exploded view showing different parts of the tool. 
         FIGS.  4 A-D  are section views showing the tool in a run-in positon in a wellbore, the tool having a slip assembly and a packer assembly. 
         FIGS.  5 A-D  are section views showing the tool with slips of the slip assembly set in the wellbore and a locking system of the packer assembly in a locked position. 
         FIGS.  6 A-D  are section views showing the tool in the wellbore with the locking system of the packer in an unlocked position. 
         FIGS.  7 A-D  are section views of the tool showing the packer set in the wellbore. 
         FIG.  8    shows the tool run into a wellbore on a work string with a cutting tool disposed on the string therebelow. 
         FIG.  9    shows another view of the tool run into a wellbore on a work string with a cutting tool disposed on the string therebelow. 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments of the present disclosure including a tool having a slip assembly and a packer assembly having a locking system to prevent inadvertent or premature setting of the packer. 
       FIG.  1    is a front view of a tool  100  according to one embodiment of the invention. The tool described herein is one that includes a slip assembly  200  and a packer assembly  300 , with the packer having a locking system  400  that prevents operation of and setting of the packer until certain conditions are met. Embodiments as shown in  FIGS.  8  and  9    also include a cutting tool  30  disposed below the tool  100  on the same work string  20 . It will be understood however that any number of different tools could be utilized with the tool described herein and the locking system described in relation to the packer assembly  300  is of use on any number of different tools where inadvertent actuation is a potential problem.  FIG.  2    is a section view of the tool  100  of  FIG.  1   . 
       FIG.  3 A  is an exploded view showing different parts of the tool  100 . The portions illustrated generally refer to the slip assembly  200  visible in an assembled manner in  FIGS.  4 A , B. Included are a cap  203 , an upper  205  and lower  210  piston surfaces as well as a spring  212  and spring housing  215  to bias the plurality of slips in a run-in and unset position. A slip housing  225  is shown as well as an exemplary slip  220  and slip retainer  230 . The various parts of the slip assembly  200  are installed on a mandrel  110 . 
       FIG.  3 B  is an exploded view showing the parts of the slip assembly  200  as well as a portion of the locking system  400  for the packer assembly  300 . Areas of  FIG.  3 B  labeled A and B correspond to similarly labeled areas of  FIG.  3 C . Visible is a housing for sub-assemblies  252  with anti-rotation keys  256  and ribs  115  disposed there upon. The keys interact with key slots  258  formed in piston body adjacent piston surface  210  and ribs  115  interact with slots  130  ( FIG.  3 D ) to permit axial but not rotational movement. Fluid passageways  254  serve to provide a fluid path for fluid used to set the slip assembly  200 . Also visible are portions of the slip assembly  200  with the slips  220  installed as well as the upper and lower piston bodies with piston surfaces  205 ,  210  formed thereon for flow-actuating the slips. Also shown are portions of the locking system  400  for the packer assembly  300  consisting of a collet sleeve  410  having displaceable collet fingers  415  and stop sleeve  336 , the functions of which will be described herein. 
       FIG.  3 C  is an exploded view showing different parts of the tool. On the left hand side of the tool are packer elements  320  separated by spacers  321  that correspond to area A of  FIG.  3 B  and will be disposed on the mandrel  110  below the slip assembly  200  of  FIG.  3 B . A slot housing  325  includes slots  330  that correspond to the anti-rotation ribs  115  of  FIG.  3 B . On the right side of the Figure are additional portions of the locking system  400  for the packer including a collet housing  420  for housing the collet sleeve  410  of  FIG.  3 B  as well as a spring loaded sleeve  425  and a spring  430  and spring housing  431  for urging the sleeve upwards into contact with the collet sleeve  410 . 
       FIG.  3 D  is an exploded view showing different parts of the tool. In the center of the Figure is the mandrel  110  constructed and arranged to be rotatable in order to rotate another tool (not shown) disposed on the lower end of mandrel via threads  112 . The mandrel includes radially disposed fluid slots  235  for the passage of fluid in order to set the slip assembly  200 . On each side of the Figure are components, most of which are prevented from rotation by a keyed arrangement between a ring with lugs  120  that operates in conjunction with a sleeve  125  having mating vertical slots  130  permitting axial but not rotational movement between the components. A bearing member  135  facilitates the rotation of the mandrel  110  and other center portions of the assembly in relation to the outer portions. 
       FIGS.  4 A-D  are section views showing the tool  100  in a run-in positon in a wellbore, the tool including the slip assembly  200  and packer assembly  300  with its locking system  400 . In this document the term “wellbore wall” refers to an inside wall of a tubular that lines the earthen borehole. Portions of the slip assembly already introduced are visible in  FIG.  4 A  including the cap  203 , upper and lower piston surfaces  205 ,  210  and a port  235  providing a fluid path between an interior of the mandrel  110  and the two piston surfaces. The fluid path includes ports  235  formed in the mandrel  110  as well as fluid passageways  254  formed in the sub-assembly housing  252 .  FIG.  4 B  illustrates additional portions of the slip assembly  200  including the slips  220  and a conical shape  240  that serves to urge the slips outwards and into contact with the wellbore wall as they are set. Generally, the slip assembly includes a number of slips  220  constructed and arranged to be urged along the conically shaped member  240  and into a wedging relationship with the walls of the surrounding wellbore  101 . 
     In the embodiment shown, the slips  220  are biased in an unset position by spring  212 , the force of which must be overcome to move the cap/slip combination downwards in relation to the conical shape  240 . The slips are further held in the run-in position by set screws  245  temporarily connecting the slip members to the conical shape  240 . The slip assembly  200  is flow-actuated by pumping fluid through the work string ( 20 ;  FIG.  8   ) upon which the tool  100  is mounted and run into the well. Port  235  (there are typically several radially spaced around the mandrel) located in a wall of the mandrel  110  permits fluid communication between the work string ( 20 ;  FIG.  8   ) and the two piston surfaces  205 ,  210 , one associated with the slip members and one associated with that part of the assembly on which the conical shape  240  is formed. Fluid pressure separates the two pistons and in doing so, overcomes the bias of the spring  212 , causing the set screws  245  to fail and moves the slips  220  to a set position as shown in  FIGS.  5 A-D . The slips are thereafter retained in the set position due to an upward force applied to the mandrel  110  from the surface which creates a wedge-like condition between the conical shape  240 , slips  220 , and the wellbore wall  101 . 
     Shown primarily in  FIGS.  4 B-D  is the packer assembly  300  with its locking system  400 . The packer is unset. Shown in  FIG.  4 B  are the packing elements  320  and spacers  321  of  FIG.  3 C , each of which is compressible. The elements are retained at an upper end by a downwardly facing shoulder of the conical shape  240  and at a lower end by an upward facing shoulder movable relative to the underside in order to compress the packer elements. As the slips are set in the wellbore, the packer assembly  300  remains in its original, unset position. 
       FIGS.  5 A-D  are section views showing the tool with slips of the slip assembly set in the wellbore and the locking system  400  of the packer retaining the packer in its unset position. Fluid pressure delivered through port  235  has moved lower piston  210  to a lower positon relative to the port and with it, the cap  203  which has compressed the biasing spring  212  that was biasing the slip assembly  200  in the run-in positon. As can be appreciated from  FIG.  5 B , the set screws  245  have failed and the slips  220  have moved down and out along the conical shape  240  and into contact with the walls of the wellbore  101 . Although the slips  220  have been set, the packer assembly  300  remains in the unset position. 
     The locking system  400  of the packer  300  prevents its inadvertent actuation. The locking system includes the collet sleeve  410  with its radially disposed fingers  415 , all of which must be deflected inwardly in order to unlock the packer and allow it to be set. In  FIG.  4 C  two of the fingers are visible. An enlarged view of the locking system in the area of the fingers  415  is provided on the left side of the Figure. Each finger has an outwardly facing tab  435  that, in the locked positon rests above an inwardly facing upset  440  that extends around an adjacent inner surface  442  of the collet housing  420 . The upset  440  can also be appreciated in  FIG.  3 C . To unlock the packer, it is necessary to move the collet housing upwards in relation to the collet sleeve  410 . The position of the upset  440  under the tabs  435  prevents that from happening until enough upwards force is applied to the collet housing to allow an angled surface  416  of the upset  440  to interact with a corresponding angled surface  418  of the fingers and deflect the fingers inwards far enough for the upset to move past the fingers ( FIG.  6 C ). Just below the tabs  435  of the fingers  415  is a spring-loaded sleeve  425  biased upwards by a spring  430  against an underside of the upset. The purpose of the sleeve is to keep the collet fingers in their deflected position as the collet housing  420  moves upwards as the packer elements  320  are compressed from below. In one embodiment, the sleeve  425  is dimensioned whereby the tabs  435  are forced inwards an additional distance as can be appreciated by comparing  FIGS.  5 C,  6 C, and  7 C . The purpose of an additional, slight deflection is to facilitate resetting of the locking system whereby two “steps” are created as the tabs move outwards to their original, non-deflected position as shown in  5 C. 
       FIGS.  6 A-D  are section views showing the tool in the wellbore with the slip assembly  200  set and the locking system  400  of the packer in an unlocked position. As shown clearly in  FIG.  6 C , the components of the packer assembly  300  and locking system are shown at the instant when the packer is unlocked due to relative movement between the inwardly facing upset  440  of the collet housing  420  and the outwardly facing tabs  435  of the collet fingers  415 . As illustrated, the collet fingers have been deflected inwards due to upward force applied to the collet housing  420  which has permitted a sliding action between angles  416 ,  418  of the upset  440  and tabs  435  of the fingers  415 . The tabs of the displaced fingers have come to rest on an upper end of the spring-loaded sleeve  425  in order to keep them deflected and permit the locking system  400  to be re-set if needed. 
     The force required to deflect the fingers and “unlock” the locking mechanism of the packer assembly  300  is supplied from the surface where, in one embodiment, 70,000 lbs. of upward force is required over and above the upward force already keeping the slip assembly  200  set against the wellbore wall. The upward force on the work string ( 20 ;  FIG.  8   ) acts primarily on an enlarged diameter portion  140  of the mandrel  110  visible in  FIG.  6 D . The enlarged diameter portion serves to urge the movable parts of the lower portion of the assembly, including the collet housing  420  upwards as if they are being pushed, in order to set the packer once the locking system has been unlocked. The distance needed to compress the elements  320  and set the packer is a distance equal to the gap  335  shown between L-shaped member  250  and stop sleeve  336  in  FIG.  6 D . 
       FIGS.  7 A-D  are section views of the tool showing the packer assembly  200  set in the wellbore  101 . As with  FIGS.  5 A-D  and  6 A-D, the slip assembly  200  remains set due to upward fore on the mandrel  110  via a work string ( 20 ;  FIG.  8   ) from the surface of the well. Comparing the Figures to  6 A-D, the upward force applied to unlock the packer assembly has moved the mandrel and its enlarged diameter portion upwards along with the collet housing  420 . The result is a movement between the parts equal to the gap  335  shown in  FIG.  6 D . The portions of the locking system are in essentially the same position as they were in  FIGS.  6 A-D . However, that part of the assembly associated with the collet housing  420  has moved upwards in relation to the collet sleeve  410  in order to compress the packer elements  320 . In  FIG.  7 D , the gap  335  of  FIG.  6 D  has now been closed, reflecting the distance that the elements  320  have been compressed. As described herein, the locking system  400  of the packer assembly  300  requires a high upward force on the work string ( 20 ;  FIG.  8   ) to move the upset  440  of the collet housing  420  against the tabs  435  of the fingers  415  in order to displace the fingers inward and permit upward movement of the housing. Once unlocked, the movement required to actually set the packer and compress the element requires little force and, due the upward force remaining on the string, takes place instantaneously. As shown in  FIGS.  7 A-D , the packer element has been compressed between the underside  241  of the conical shape  240  and the upward facing shoulder formed at the lower end of the element. 
     In operation, the assembly of the present invention can be utilized in a number of different ways. In one example as shown in  FIG.  8   , the tool  100  is used with a cutting tool  30  for separating an upper portion of a casing  12  in the wellbore  101  from a lower portion. Cutting tools for severing tubulars in a wellbore are well known. One example is described in US patent publication number 2018/0258734 assigned to the same assignee as the present invention and that publication is incorporated herein in its entirety. Preferably, the cutting tool  30  has radially extendable cutters (not shown) that extend outwardly at a predetermined time into contact with the walls of the surrounding tubular. Thereafter, the tubing  12  is severed by rotational movement of the cutting tool  30 . As described herein, a center portion of the tool  100 , including the mandrel ( 110 ) is constructed and arranged to be rotatable relying in part on bearing member ( 135 ) and various keyed relationships between portions of the tool, like the ring with lugs ( 120 ) and slots ( 130 ) of sleeve ( 125 ). 
     In one embodiment as shown in  FIG.  8   , the tool  100  is run into a wellbore  101  on a work string  20  with a cutting tool  30  disposed on the string  20  therebelow. The purpose of the operation is to sever a tubular  12  lining the wellbore  101 . The combination of tools  100 ,  30  is run into a location adjacent the location where the surrounding tubular  12  is to be severed. Thereafter, fluid is pumped through the work string  20  and through port ( 235 ) formed in a wall of the mandrel ( 110 ). As the fluid acts upon two opposing piston surfaces ( 205 ,  210 ), set screws ( 245 ) pinning the slips ( 220 ) in a run-in position relative to the conical shape ( 240 ) are broken and the slips are moved downwards along the conical member and into contact with the walls of the surrounding tubular  12 . Thereafter, an upward force is applied to the work string  20  to keep the slips set in a wedging relationship between the conical shape and the wellbore  101 &#39;s wall. With the tool combination fixed in a predetermined location in the wellbore  101 , the cutting tool  30  is operated by rotating the work string  20  from the surface while upward force is maintained to keep the slips set. Once the cutting tool  30  has successfully severed the tubular  12 , the entire assembly ( 20 ,  30 ,  100 ) including the upper portion of the tubular  12  is lifted using the slips that remain engaged. Due to the weight of the severed tubular  12  being lifted, the packer in most cases will be unlocked and moved to a set positon. However, in this operation having the packer set has no bearing on the result of retrieving the tubular portion to the surface of the well. 
     In another scenario, the operation is carried out as above but, due to interference by wellbore debris between the tubular  12  lining the wellbore  101  and the borehole therearound, the severed tubular  12  cannot be successfully lifted. In this instance, additional lifting force is applied to the work string  20  from the surface of the well. At about 75,000 lbs. of force, the locking system  400  of the packer assembly  300  is unlocked according to the operations described in relation to the forgoing Figures, especially  FIGS.  5 C and  6 C . Thereafter, fluid is pumped out a lower end of the string, below the cutting tool where it “washes” the area between an outer surface of the tubular and the borehole therearound using the area where the tubular was cut as a fluid path to the outer surface. In this manner, debris such as dirt that can hamper the lifting and separation of the upper portion of the tubular from the lower portion can be disturbed. In some instances, such as shown in  FIG.  9   , a barrier  40 , such as another packer, is set below the cutting tool  30  so that the washing fluid is trapped between the lower packer  40  and the packer of the tool  100 , forcing it out of the tubular  12  and into the area of the borehole. In other instances, as shown in  FIG.  9   , a cement plug previously placed in the wellbore  101  creates the barrier  40  below the tool. In addition to its “washing” function, the fluid pumped between the packers/cement plug can be pressurized and provide additional lifting force. If the operation is successful, the tool  100 , cutting tool  30  and upper section of tubular  12  are lifted to the surface with the slip and packer assembly remaining set. 
     In yet another scenario, the initial lifting is unsuccessful and the washing procedure described above is also unsuccessful in loosening the upper portion of tubular  12  to a point where it can be dislodged and raised. In this case, the entire assembly including the tool  100  and cutting tool  30  can be repositioned at another, typically higher location where the process will be attempted again. In order to reposition the assembly, the slips and packer must first be unset. By reducing lifting force on the work string  20 , the locking system  400  of the packer assembly  300  is first re-set as the collet housing  420  with its inwardly facing upset  440  is moved down relative to the collet sleeve  410  with its displaced fingers  415  with their outwardly extending tabs  435 . Due to the same angles  416 ,  418  of the upset  440  and tabs  435 , the re-setting of the locking system requires relatively little force compared to the 70,000 lbs. necessary to move them to the unlocked position. Once the packer is returned to its unset position with its locking system re-set, additional downward movement releases the slips and the spring-loaded cap urges the slips to their run-in position. Thereafter, the assembly including the tool  100  and cutting tool  30 , or any other tool attached thereto, can be raised to a higher location in the wellbore  101  where the slip assembly  200  will be reset and if needed, the locking system  400  of the packer  300  can be unlocked and the packer set just as it was in the prior attempt. 
     While the foregoing is directed to embodiments of the present disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.