Patent Publication Number: US-11649687-B1

Title: High expansion anti-rotation anchor catcher

Description:
FIELD 
     There is described a high expansion anchor, which was developed for use with a progressive cavity pump (PC Pump) for preventing rotation of the PC Pump and associated tubing string and vertically arrest (“catch”) the PC Pump from falling down the well, but potentially has other applications. 
     BACKGROUND 
     An anti-rotation anchor is used with a PC pump to stop rotation of the tubing string caused by pump rotation. Rotation of the tubing string can cause a backing off of threaded connections and the loss of the PC pump down the well. 
     U.S. Patent Publication 215/0233199 (Moore et al) titled “Quarter Turn Tubing Anchor Catcher” describes a tubing anchor which is set by rotation in a first direction and released by rotation in a second direction. 
     U.S. Pat. No. 6,796,380 (Xu) titled “High Expansion Anchor System” describes an anchor system that uses linkages to increase the expansion limit of the anchor system. 
     SUMMARY 
     There is provided a high expansion anti-rotation anchor catcher which includes a tubular body having an axis, a first end, a second end, and an exterior surface. At least one coupling is positioned at the first end of the tubular body or the second end of the tubular body. A helical track is positioned on the exterior surface of the tubular body. An expandable gripper cage is provided having an axially fixed hub mounted for rotation about the tubular body and an axially movable hub mounted for rotation about the tubular body. Pivoting linkages which support outwardly oriented grippers extend between the axially fixed hub and the axially movable hub. The axially movable hub has a track follower that engages the helical track on the exterior surface of the tubular body. Rotation of the tubular body in a first rotational direction causes the track follower to move along the helical track toward the axially fixed hub, thereby placing the expandable gripper cage in compression and causing the pivoting linkages and grippers to pivot outwardly away from the tubular body. Rotation of the tubular body in a second rotational direction causes the track follower to move along the helical track away from the axially fixed hub, thereby placing the expandable gripper cage in tension and causing the pivoting linkages and grippers to pivot inwardly toward the tubular body. 
     The high expansion anti-rotation anchor catcher, as described above, is easily set in position downhole by rotation of the tubing string. Should the operation of the PC pump impart a further rotational force, any rotation of the tubular body merely serves to further expand the expandable gripper cage. The range of expansion of the high expansion anti-rotation anchor catcher allows the high expansion anti-rotation anchor catcher to be used with different sizes of pipe. It also allows for a measure of safety, as a high expansion anti-rotation anchor catcher that is functioning at its outer expansion limit could become dislodged if a great enough force is applied. The tool serves as both an anti-rotation role to anchor against rotation and a catcher role to vertically arrest (“catch”) the PC pump and prevent it from falling down the well. 
     To assist in running the high expansion anti-rotation anchor catcher into and out of the well, it is preferred that centralizers be provided. To fulfil this function, an expandable centralizer cage is provided having an axially slidable hub that slides axially along the exterior of the tubular body toward a second hub. Pivoting linkages which support centralizer blocks extend between the axially slidable hub and the second hub. A spring is provided which acts against a shoulder on the exterior surface of the tubular housing to exert a force upon the axially slidable hub urging the axially slidable hub along the exterior of the tubular body toward the second hub. This places the expandable centralizer cage in compression and causes the pivoting linkages and centralizer blocks to pivot outwardly away from the tubular body. 
     In operation, the spring compresses the expandable centralizer cage which causes the centralizer blocks to engage the inside of the pipe as the high expansion anti-rotation anchor catcher is inserted into or drawn out of the well. 
     In order to keep the tubular body of the high expansion anti-rotation anchor catcher as short as possible, it is preferred that the axially movable hub of the expandable gripper cage serve as the second hub for the expandable centralizer cage. This also plays a role in deployment of expandable gripper cage, as it maintains the expandable gripper cage in a stationary position while the tubular body rotates. 
     When the high expansion anti-rotation anchor catcher is to be positioned below the PC Pump, it is possible to provide the high expansion anti-rotation anchor catcher with a single coupling. However, if the high expansion anti-rotation anchor catcher is to be positioned above the PC Pump, two couplings are required. To provide maximum flexibility, it is preferred that a first coupling be positioned at the first end of the tubular body and a second coupling be positioned at the second end of the tubular body. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other features will become more apparent from the following description in which reference is made to the appended drawings, the drawings are for the purpose of illustration only and are not intended to be in any way limiting, wherein: 
         FIG.  1    is a perspective view of a high expansion anti-rotation anchor catcher 
         FIG.  2    is a detailed side elevation view of the expandable gripper cage of the high expansion anti-rotation anchor catcher of  FIG.  1   . 
         FIG.  3    is a detailed side elevation view of the expandable centralizer cage of the high expansion anti-rotation anchor catcher of  FIG.  1   . 
         FIG.  4    is a side elevation view of pivotal links and gripper of the expandable gripper cage of the high expansion anti-rotation anchor catcher of  FIG.  1   . 
         FIG.  5   , is a section view of the pivotal links and gripper, taken along section lines A-A of  FIG.  4   . 
         FIG.  6    is a section view of the high expansion anti-rotation anchor catcher positioned in a pipe of a producing oil well. 
     
    
    
     DETAILED DESCRIPTION 
     A high expansion anti-rotation anchor catcher generally identified by reference numeral  10 , will now be described with reference to  FIG.  1    through  FIG.  6   . 
     Structure and Relationship of Parts: 
     Referring to  FIG.  1   , high expansion anti-rotation anchor catcher  10  includes 
     a tubular body  12  having an axis  14  (indicated in broken lines), a first end  16 , a second end  18 , and an exterior surface  20 . A first coupling  22  is positioned at first end  16  of tubular body  12 . A second coupling  24  is positioned at second end  18  of tubular body  12 . A helical track  26  is positioned on exterior surface  20  of tubular body  12 . Positioned around tubular body  12  is an expandable gripper cage, generally indicated by reference numeral  30 , which will hereinafter be further described. Also positioned around tubular body  12  is an expandable centralizer cage, generally indicated by reference numeral  50 , which will hereinafter be further described. 
     Referring to  FIG.  2   , expandable gripper cage  30  consists of an axially fixed hub  32  mounted for rotation about tubular body  12  and an axially movable hub  34  mounted for rotation about tubular body  12 . Pairs of pivoting linkages  36  and  38  which support outwardly oriented grippers  40  extend between axially fixed hub  32  and axially movable hub  34 . Axially fixed hub  32  has a track follower  42 , in the form of set screws that engage a circular track (not shown) on exterior surface  20  of tubular body  12 . (Set screws have been used for convenience of assembly, it will be understood that track follower  42  can be pins, protrusions or take other forms as long as they function to follow the track) This engagement facilitates rotation of axially fixed hub. Axially movable hub  34  has a track follower  44 , in the form of set screws, which engages helical track  26  on exterior surface  20  of tubular body  12 . (Set screws have been used for convenience of assembly, it will be understood that track follower  44  can be pins, protrusions or take other forms as long as they function to follow the track) 
     As will hereafter be further described, rotation of tubular body  12  in a first rotational direction causes the track follower  44  to move along helical track  26  toward axially fixed hub  32 . This movement places expandable gripper cage  30  in compression and causes pivoting linkages  36  and  38  with grippers  40  to pivot outwardly away from tubular body  12 . Rotation of tubular body  12  in a second rotational direction causes the track follower  44  to move along helical track  26  away from axially fixed hub  32 , thereby placing expandable gripper cage  30  in tension and causing pivoting linkages  36  and  38  and gripper  40  to pivot inwardly toward tubular body  12 . 
     Referring to  FIG.  4   , pivoting linkages  36  and  38 , with associated gripper  40 , are illustrated. Gripper  40  has on its surface carbide buttons  45 . Referring to  FIG.  5   , pivot pins  46  pivotally connect gripper  40  with pivoting linkages  36  and  38 . Pivot pins  48  connect pivoting linkages  36  and  38 , with axially fixed hub  32  and axially movable hub  34 , respectively. Gripper  40  has a tooth  41 . Tooth  41  is pivotally mounted on a support pin  43  and is biased outwardly by a torsion spring  47 . As will hereinafter be further described, tooth  41  is serves to prevent gripper  40  from becoming dislodged by rotation as a result of torque imparted by the PC pump. Tooth  41  is sometimes referred to in the industry as a “door”, because tooth  41  pivots and swings outwardly in the manner similar to or reminiscent of a door. 
     Referring to  FIG.  3   , expandable centralizer cage  50  has an axially slidable hub  52  that slides axially along exterior surface  20  of tubular body  12  toward the axially movable hub  34  of expandable gripper cage  30 . Pivoting linkages  54  and  56  which support centralizer blocks  58  extend between axially slidable hub  50  and the axially movable hub  34  of expandable gripper cage  30 . A spring  60  is provided which acts against a shoulder  62  on exterior surface  20  of tubular housing  12  to exert a force upon axially slidable hub  50  urging axially slidable hub  50  along exterior  20  of the tubular body  12  toward axially slidable hub  34 . As will hereinafter be further described, this movement places expandable centralizer cage  50  in compression and causes pivoting linkages  54  and  56  and centralizer block  58  to pivot outwardly away from tubular body  12 . Spring  60  has been illustrated as a coil spring. It will be understood that a leaf spring or other form of spring could be used. 
     Operation: 
     Referring to  FIG.  1   , first coupling  22  and second coupling  24  are used to secure high expansion anti-rotation anchor catcher  10  to a tubing string being run into a pipe of an oil producing well. As previously noted, anti-rotation anchor  10  may be positioned either above or below a PC pump. During insertion, expandable gripper cage  30  is not deployed and is at rest with pivoting linkages  36  and  38  together with grippers  40  positioned as close as possible to tubular body  12 . However, expandable centralizer cage  50  maintains anti-rotation anchor  10  in a central position, to avoid problems during insertion. Referring to  FIG.  3   , spring  60  acts against shoulder  62  on exterior surface  20  of tubular housing  12  to exert a force upon axially slidable hub  50  urging axially slidable hub  50  along exterior  20  of the tubular body  12  toward axially slidable hub  34 . This movement places expandable centralizer cage  50  in compression and causes pivoting linkages  54  and  56  and centralizer blocks  58  to pivot outwardly away from tubular body  12 . Referring to  FIG.  3   , centralizer blocks  58  on all sides of tubular body  12  contact pipe  100  of the oil producing well. 
     Once the PC pump has been inserted down the well at the end of the tubing string to a desired pumping depth, expandable gripper cage  30  is activated. As previously described, that activation involves rotation of tubular body  12  in a first rotational direction. This is accomplished by rotating the entire tubing string. As noted above, at the time of activation of expandable gripper cage  30 , expandable centralizer cage  50  has already been deployed and centralizer blocks  58  on all sides of tubular body  12  are in contact with pipe  100  of the oil producing well. This results in expandable gripper cage  30  remaining in a stationary position while tubular body  12  rotates. Referring to  FIG.  2   , rotation in a first direction the track follower  44  on axially movable hub  34  to move along helical track  26  toward axially fixed hub  32 . This movement places expandable gripper cage  30  in compression and causes pivoting linkages  36  and  38  with grippers  40  to pivot outwardly away from tubular body  12  to engage pipe  100 , as shown in  FIG.  6   . Rotational force created by the PC pump during operation further rotates tubular body  12  results in the track follower  44  on axially movable hub  34  moving a little further along helical track  26  toward axially fixed hub  32  and causes grippers  40  to engage more forcefully. Tooth  41  biased outwardly by spring  47 , engages pipe  100  to prevent rotational slippage of grippers  40 . Once expandable gripper cage  30  is deployed with grippers  40  engaged, high expansion anti-rotation anchor catcher  10  performs an “anti-rotation” role by preventing rotation and also performs a “catcher” role by vertically arresting (“catching”) the PC pump so it does not and cannot fall down the well. 
     From time to time, PC pump will need to be repositioned or brought up to surface for servicing. In order to release high expansion anti-rotation anchor catcher  10 , it will be understood that rotation of tubular body  12  in a second rotational direction causes the track follower  44  on axially movable hub  34  to move along helical track  26  away from axially fixed hub  32 , thereby placing expandable gripper cage  30  in tension and causing pivoting linkages  36  and  38  and gripper  40  to pivot inwardly toward tubular body  12 . 
     In this patent document, the word “comprising” is used in its non-limiting sense to mean that items following the word are included, but items not specifically mentioned are not excluded. A reference to an element by the indefinite article “a” does not exclude the possibility that more than one of the element is present, unless the context clearly requires that there be one and only one of the elements. 
     The scope of the claims should not be limited by the illustrated embodiments set forth as examples, but should be given the broadest interpretation consistent with a purposive construction of the claims in view of the description as a whole.