Abstract:
A key assembly is press fit into an annular space between a box and pin member to resist relative rotation of the box and pin members. The key assembly includes wedge like members that contact one another along complementary tapered surfaces, and when in contact generate radial forces into the box and pin member to secure the connection between the box and pin. The outer wedge is inserted first into the annular space between the box and pin members, and has rows of elongate teeth that project radially outward into contact with an inner surface of the box member. Because the outer wedge is pushed radially outward against the box member rather than axially sliding therebetween, the teeth protrude into the surface of the box member thereby increasing the anti-rotation force created by the outer wedge.

Description:
FIELD OF THE INVENTION 
       [0001]    This invention relates in general to threaded tubular connections, such as for offshore oil well large diameter pipe, and particularly to a device to prevent rotation of threaded members after they are made up. 
       BACKGROUND OF THE INVENTION 
       [0002]    Oil and gas wells can have several strings of casing of differing diameters cemented in the well. Each casing string is usually made up of joints of pipe having threaded ends secured together. A typical casing joint has external threads on its upper and lower ends. A casing collar with internal threads secures the threaded ends together. In larger casing diameters, a box connector with internal threads may be affixed, such as by welding, to one end of each pipe, the other end having a pin connector with external threads. Normally, the operator relies on the friction of the made-up joint preventing the threaded connectors from loosening while running the string into the well. With larger diameter casing, for example, from 16 inch to 36 inch, the friction of the made-up connector may be inadequate to prevent loosening while running the casing. 
         [0003]    Operators have employed anti-rotation keys to prevent loosening. A rectangular pocket or slot is machined on the outer surface of the pin connector. The box connector is machined to include tabs that accept the anti-rotation key. The box connector tab and pin connector pocket will line up after making up the connectors. The workers will then drive a key through the box connector tab and into the pin connector pocket. The key has a slightly greater thickness than the distance from the box connector tab to the innermost wall of the pin connector pocket, resulting in an interference fit. The workers typically will drive the key into place with a hammer In some easing setups, the key inserts through a threaded hole in the box connector tab and a wrench may be employed to position and secure the key. 
       SUMMARY 
       [0004]    Disclosed here in is an example of a connection system for a tubular string. In one example the system includes a box end on an end of a second tubular, a pin end on an end of a first tubular, where the first tubular is selectively inserted into the box end. Also included is a key assembly that includes interface and backing members that are wedged together in an annular space between the box end and pin end and frictionally couple to both the box end and pin end. A pocket can be provided in the annular space between the box end and pin end, wherein the pocket extends along a portion of the circumference of the box end. The interface and backing members may have complementary tapered surfaces, and wherein when the backing member is inserted into the annular space a and the tapered surfaces are in sliding contact, the interface and backing members project radially outward into frictional engagement with the box and pin members. In an example, the interface member has teeth on a radially outward projecting surface that engage an inner surface of the box member when the backing member is inserted into the annular space. Optionally, an inset groove is formed on an outer radial surface of the backing member that is selectively engaged by a wedge installation tool. In one embodiment, the hacking member has an upper portion and a lower portion, wherein the upper portion has a downward facing surface that selectively lands on an upper surface of the box end when the backing member is inserted into the annular space. In this example, the lower portion of the backing member has a tapered surface that is complementary to a tapered surface on a radially inward facing surface of the interface member. Further in this example, teeth are on the tapered surfaces of the backing member and the interface member. 
         [0005]    Also disclosed herein is a connection joint for downhole tubulars, that in one example includes a box member having an open end, a pin member inserted into the open end to define an annular space between the box member and the pin member, an interface member in the annular space having an outer radial surface in contact with a portion of the pocket in the box member, and a backing member wedged into the annular space between the interface member and the pin member. In this example, a radial force is exerted across the interface member, backing member, pin member, and box member that counters a rotational force on one of the box member and pin member. Optionally, an inner radial surface of the backing member in the annular space contacts an outer radial surface of the pin member along an interface that is generally parallel with an axis of the pin member. The backing member can include an upper portion with an inset groove selectively engaged by a wedge installation tool. In an example, an outer radial surface of the backing member and inner radial surface of the interface member are tapered along complementary angles, so that when the backing member and interface member are inserted into the annular space, the backing member and interface member are in contact along an interface that is oblique with an axis of the pin member. The backing member can insert into a pocket formed on an outer surface of the pin member. 
         [0006]    A method of handling a downhole tubing string is disclosed herein. In one example the method includes providing a wedge shaped interface member with teeth on an outer radius, inserting the interface member into an annular space between a pin member and a box member, providing a wedge shaped backing member, and inserting the backing member into the annular space and between the interface member and pin member. Inserting the backing member creates a radial force that is exerted into the box member and pin member that counters relative rotation of the box member and pin member. The teeth can project into the box member when the backing member is inserted into the annular space. Optionally, the backing member includes a groove on an outer radial surface, the method further involves coupling a hydraulic tool with the groove to insert the backing member into the annular space. In an example, the backing member includes a groove on an outer radial surface, the method further includes coupling a hydraulic tool with the groove to remove the backing member from the annular space. A pocket can be formed on an outer surface of the pin member, and wherein a portion of the backing member inserts into the pocket. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1  is a side partial sectional view of an example of a tubular connection secured by an embodiment of an anti-rotation system in accordance with the present invention. 
           [0008]      FIG. 2  is a side elevational view of interface and backing members of the anti-rotation system of  FIG. 1  in an unset configuration and in accordance with this invention. 
           [0009]      FIG. 3  is a side elevational view of interface and backing members of the anti-rotation system of  FIG. 1  in a set configuration and in accordance with this invention. 
           [0010]      FIG. 4  is a perspective view of interface and backing members of the anti-rotation system  FIG. 1  in an unset configuration and in accordance with this invention. 
           [0011]      FIG. 5  is a perspective view of interface and backing members of the anti-rotation system of  FIG. 1  in a set configuration and in accordance with this invention. 
           [0012]      FIGS. 6 and 7  are side perspective views of an example of a key handling tool installing interface and backing members in a tubular connection and in accordance with the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0013]    Referring to  FIG. 1 , a first pipe  11  has a cuff-like box member  13  on one end with internal threads  15  on an inner surface adjacent box member  13 . The internal diameter of pipe  11  increases along portion having threads  15  and proximate box member  13 . The box member  13  has a smooth surfaced internal rim  17  circumscribing an upper inner surface. In this embodiment, the box member  13  has an outer surface  19  that is substantially smooth. A pipe connection  21  is shown having a annular space  23  formed by the internal rim  17  of the box member  13  and between an outer surface  25  of a pin member  27 . The pin member  27  is formed on the end of a second pipe  29  and has a set of external threads  31  that engage with the internal threads  15  of the box member  13 . The second pipe  29  and the box member  13  are rotated relative to each other to make up a joint. A pocket  32  is shown formed into the outer surface of the pin member and radially inward from annular space  23 . In the example of  FIG. 1 , the pocket  32  extends along a portion of the circumference of the annular space  23 . In an alternate embodiment, a series of pockets  32  are provided along the circumference of the pipe connection  21 . 
         [0014]    An interface member  33  is shown having outward facing teeth, which can be selectively inserted into the annular space  23 . The interface member  33  have a lower support shoulder  35  that rests against the bottom portion of the annular space  23  for positioning the interface member  33  in preparation for insertion of a backing member  37 . The backing member  37  can be selectively inserted into the annular space  23 , and so its lower portion is within pocket  32 . The presence of the backing member  37  in the annular space  23  radially directs the previously inserted interface member  33  towards the internal rim  17  of the box member  13 , thereby rotationally coupling the first pipe  11  and the second pipe  29 . In an example, the backing member  37  and interface member  33  define a key assembly that when wedged into the annular space  23  engage with each other and frictionally engage the box and pin members  13 ,  27  thereby rotationally coupling the box and pin members  13 ,  27 . In the example of  FIG. 1 , the outer radial surface of the interference member  33  and inner radial surface of the backing member  37  are each generally parallel with an axis A X  of pipe  29 . However, alternate embodiments exist where one or both of the inner and outer radial surfaces of members  33 ,  37  are oblique to the axis A X . 
         [0015]      FIG. 2  illustrates a side elevational view of an example of an unset position of the interface member  33  and the backing member  37 . The lower support shoulder  35  of the interface member rests in the annular space  23  (as shown in  FIG. 1 ), while the backing member  37  is pushed downward into the annular space  23 . In an embodiment, the backing member  37  can have a generally rectangular upper portion having a beveled surface on an upper edge that faces radially outward. An inset groove  39  is provided on the outer radial surface, which has a generally rectangular cross section. A lower portion of the backing member  37  depends down from its upper portion having a generally triangularly shaped cross section to define a wedge shaped section  41 . The wedge shaped section  41  has a radially outward facing tapered surface  43  profiled with a series of grooves  44  extending along its width. Further in the example of  FIG. 2 , a lower end of tapered surface  43  is shown mating with an upper end of a tapered surface  45  provided on a radially inward facing side of the backing member  37 . Grooves  46  are formed along a width of tapered surface  45  that engage grooves  44 . In one embodiment, surfaces  43 ,  45  are tapered to complementary angles, so that when the backing member  37  slides into engagement with the interface member  33 , an interface is formed along an axial length of these surfaces  43 ,  45  that is oblique to the axis A X  ( FIG. 1 ). 
         [0016]      FIG. 3  illustrates a side elevational view of the interface member  33  and the backing member  37  in a set position and with their respective grooves  44 ,  46  engaged with one another. Moreover, inserting the backing member  37  into the annular space  23  so the tapered surfaces  43 ,  45  are facing one another, exerts a radial force against the box and pin members  13 ,  27  that urge teeth  47  on a radially outward facing side of the interface member  33  to engage with a radially inward facing surface of internal rim  17 . The teeth  47  are extend along an axial path and are generally transverse to grooves  46 . Engaging the teeth  47  with rim  17 , in combination with radially inwardly pushing backing member against pin member  27 , generates forces on the pipes  11 ,  29  that opposes their relative rotational movement, thereby maintaining the pipe connection  21 . Once installed the first pipe  11  and the second pipe  29  are rotationally coupled together (as shown in  FIG. 1 ). One advantage of radially installing the interface member  33 , as described. In this embodiment, is that the teeth do not need to axially plow through the receiving material, such as internal rim  17  of the box member  13 . By not plowing through this part of the box  13 , the box  13  may last longer in an installation or be used for more installation attempts and the tubulars can see an extended useful life. 
         [0017]      FIG. 4  shows a side perspective view showing the unset position of the interface member  33  and the backing member  37 . As shown, the teeth  47  are aligned in rows that project outward from radially outward facing surface  49  of the interface member  33 . Each tooth has lateral sides that meet to define an edge along the terminal end of each tooth. In an alternate embodiment, teeth  47  may cover only a portion of surface  49 . As noted above, the tapered surfaces  43 ,  45  slide against one another was the backing member  37  is being installed in the annular space  23 . A stab guide  51  on a lower terminal end of the backing member  37  projects into a bottom of the annular space  23 , and a blocking shoulder  53  on a lower facing surface of the upper portion of the backing member  37  lands on an upper surface of rim  17  to provide a stopping position and support for the backing member  37 . In an example, the shoulder  53  is supported on the rim when the backing member  37  is in the installed position ( FIG. 1 ). 
         [0018]      FIG. 5  shows a side perspective view an example of the set position of the interface member  33  and the backing member  37 . In an alternate embodiment, guide rails (not shown) can be on the tapered surface  43  of the backing member  37 . In an example, the guide rail(s) are elongated members that project upward from the tapered surface  43  and extend along a path generally parallel with relative movement of the backing member  37  and interface member  33 . In this example, one or more recesses (not shown) can be provided on the tapered surface  45  in which guide rail(s) are received. The guide rails can help to align the backing member  37  as it is inserted into annular space  23 . The guide rails can also serve to better align the engagement of the teeth  47  of the interface piece  33 . 
         [0019]    Shown in perspective view in  FIG. 6 , is one example of securing a pipe connection against rotation by installing an interface member  33  and backing member  37  with a key installation tool  55 . The example tool  55  includes a main body  57  shown supported over a base  59  by a support rod  61 . Also extending between the base  59  and body  57  are guide rods  63  shown substantially parallel to and forward of the support rod  61 . The guide rods  63  insert into bores (not shown) formed axially through a ram  65  that is slidingly mounted on the rods  63 . A tongue  67  is formed on a forward facing surface of the ram  65 . The tongue  67  projects forward from the ram  65  in a direction opposite from support rod  61 , and extends lengthwise across the forward facing surface of the ram  65 . A shoulder  68  is also provided on an upper edge of the rain that extends lengthwise along its forward facing surface. The ram  65  is actuated on the guide rods  63  by hydraulic fluid stored in a cylinder  69  mounted on an upper surface of the body  57 . Further illustrated in  FIG. 6  is that the sidewalk of the picket  32  are sufficiently spaced apart to allow insertion of the backing member  37  therebetween. Strategic spacing of the sidewalk maintains the backing member  37  at a designated azimuth along the outer surface of the pin member  27 . 
         [0020]      FIG. 7  illustrates an example of using the key installation tool  55  to insert the backing member  37  into annular space  23  and into engagement with interface member  33  ( FIG. 6 ). In this example, a forward facing edge of the body  57  rests against box member  13 , and tongue  67  is inserted into groove  39 . Further, shoulder  68  engages an upper surface of backing member  37 . Hydraulic fluid is supplied to ram  65  via cylinder  69 , which in turn urges ram  65  downward to force backing member  37  into annular space  23 . Through its interaction of the tongue  67  into groove  39 , and shoulder  68  on the upper end of backing member  37 , the ram  65  exerts sufficient force onto backing member  37  to insert it into the annular space  23  and to engage interface member  33 . An optional cleat  71  can be included on the base  59  for engaging a lower facing surface of box member  13 . In the example of  FIG. 7 , cleat  71  is a generally planar member that has a portion extending between guide rods  63 , and a transverse forward portion that extends along a forward edge of the base  59  distal from support rod  61 .