Abstract:
Apparatus and methods for increasing the torque capacity of connections between tubular members. In some embodiments, the connection is threaded. The apparatus may include a first tubular end having a torque member moveable thereon. A second tubular end is made up with the first tubular end. The torque member is moveable back toward the second tubular end. The torque member can be moved into engagement with the second tubular end, and then torqued against the second tubular end. A first torquing interface is provided between the first tubular and the second tubular by making up their respective ends, and a second torquing interface is provided therebetween by torquing the torque member against the second tubular end. A torque capacity of the made up connection is increased thereby.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application is the U.S. National Stage under 35 U.S.C. §371 of International Patent Application No. PCT/US2009/041645 filed Apr. 24, 2009, which claims the benefit of U.S. Provisional Patent Application No. 61/047,673 filed Apr. 24, 2008, entitled “Torque Member For Threaded Connections.” 
     
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0002]    Not applicable. 
       BACKGROUND 
       [0003]    The disclosure relates to threaded tubular connections and the like. More particularly, the disclosure relates to an apparatus and method for joining tubular members using threaded sections in a manner that increases the thread torque capacity. 
         [0004]    In the oil and gas production industry, pipe or other tubular sections may be connected via threaded connections, such as mating pin and box ends. The threaded connections are often subjected to large torsion forces, such as during downhole operations like drilling. The torque or yield strength of the connection is dictated by the thread profile, the material properties and the dimensions of the mating threaded components. However, due to space or other constraints in a well bore, often times the threaded connection design is limited as to the size and thread type that can be used, thereby limiting the yield strength of the connection. It is particularly problematic to achieve increased yield strength in a connection that is made up onto the threaded pin face. Sometimes it is necessary to have a connection that is stronger than what can be achieved in an existing design. Thus, it is advantageous to increase the yield or torque strength of a threaded connection. 
         [0005]    To increase the torque capacity of a particular threaded connection, a thread locking compound (such as Loctite®) is sometimes applied to the threads. This tends to increase the friction between the mating threaded components, thus increasing the torque capacity of the overall connection. However, thread locking compounds are undesirable because the threaded connection can be very difficult to disassemble after makeup because the connection must be heated to break down the locking compound. This is a time consuming process and the high heat required to break apart the thread locking compound can damage equipment. 
         [0006]    Other attempts to increase the torque capacity of the connection include using higher strength material for the threaded components or using a double shoulder type design. However, higher strength materials are generally more expensive and might not be available. Furthermore, even high strength materials, alone, might fail to meet the high torque requirements of drilling operations. Additionally, double shoulder type threaded connections require precise dimensional tolerances among the fixed outer pin face to outer box face interface and the fixed inner pin face to inner box face interface. Should these dimensions be imprecise, similar threaded connections may have torque strengths that are dissimilar, unpredictable, and yield little advantage over standard threaded connections. 
         [0007]    Applying thread locking compound, changing the thread profile or changing material selection all present significant disadvantages when attempting to improve the yield strength of a threaded connection under high torsional loads. Thus, there remains a need for a threaded connection that advantageously increases the torque strength of a threaded connection, particularly while also staying within current downhole design specifications. 
       SUMMARY 
       [0008]    The disclosed embodiments described herein overcome the various deficiencies of the prior art by providing an apparatus and method for joining tubular members with increased torque capacity. In general, embodiments include an additional torque member that is coupled to a pin component and then back against a box component that has been made up with the pin component. The torque member may be a torque nut threaded onto a threaded pin end and then back against an outer box end face while the pin end face is made up onto an inner box face. Threading the torque member back against the outer box face increases the yield strength of the threaded connection. Additionally, the moveable torque member provides the flexibility to adjust the position of the torque member shoulder relative to the interface between the pin face and the inner box face. This flexibility avoids the need for precise dimensional tolerances associated with a fixed shoulder. 
         [0009]    In some embodiments, an apparatus for increasing the torque capacity of a tubular connection includes a first tubular member comprising a first end and a torque member moveably coupled on the first end, a second tubular member comprising a second end coupled to the first end, and wherein the torque member is moveable from a first untorqued position to a second torqued position against the second tubular member. 
         [0010]    In some embodiments, an apparatus for increasing the torque capacity of a tubular connection includes a first tubular member coupled to a second tubular member and having a first torquing interface therebetween, and a moveable torque member coupled to the first tubular member and the second tubular member and providing a second torquing interface between the first tubular member and the second tubular member. The first torquing interface may include a pin end face and an inner box face, and the second torquing interface may include a torque member face and an outer box face. 
         [0011]    In some embodiments, an apparatus for increasing the torque capacity of a threaded tubular connection includes a first tubular member including a pin end having a section of threads with an axial length, a second tubular member including a box end having a section of threads with an axial length less than the axial length of the pin end threaded section, and a torque member including a section of threads with an axial length less than the axial length of the pin end threaded section, wherein the pin end threaded section is configured to threadedly receive the torque member threaded section and the box end threaded section at the same time. 
         [0012]    In some embodiments, a method for increasing the torque capacity of a tubular connection includes connecting a torque member to an end of a first tubular member, connecting an end of a second tubular member to the end of the first tubular member, torquing the first tubular member against the second tubular member, and moving the torque member into engagement with the second tubular member while the first tubular member is torqued against the second tubular member. The method may further include torquing the torque member against the second tubular member, thereby providing a second torque interface between the first tubular member and the second tubular member. The method may further include providing a first torque capacity by torquing the second tubular member against the first tubular member and providing an additional torque capacity by torquing the torque member against the second tubular. The method may further include threading the torque member onto pin end threads of the first tubular member in a first direction, threading box end threads of the second tubular member onto the pin end threads of the first tubular member in the first direction, and threading the torque member in a second opposite direction toward the box end of the second tubular member. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    For a more detailed description of the preferred embodiments of the present disclosure, reference will now be made to the accompanying drawings, wherein: 
           [0014]      FIG. 1  is a schematic of one embodiment of a torque member apparatus; 
           [0015]      FIG. 2  is a schematic of the torque member apparatus of  FIG. 1  at a first step of assembly; 
           [0016]      FIG. 3  is a schematic of the torque member apparatus of  FIG. 1  at a second step of assembly; 
           [0017]      FIG. 4  is a schematic of the torque member apparatus of  FIG. 1  at a third step of assembly; 
           [0018]      FIG. 5  is a schematic of the torque member apparatus of  FIG. 1  at a fourth and final step of assembly; 
           [0019]      FIG. 6  is a schematic of the torque member apparatus of  FIG. 1  at a first step of disassembly; 
           [0020]      FIG. 7  is a schematic of the torque member apparatus of  FIG. 1  at a second step of disassembly; 
           [0021]      FIG. 8  is a schematic of the torque member apparatus of  FIG. 1  at a third step of disassembly; and 
           [0022]      FIG. 9  is a schematic of the torque member apparatus of  FIG. 1  at a fourth and final step of disassembly. 
       
    
    
     DETAILED DESCRIPTION 
       [0023]    In the drawings and description that follow, like parts are typically marked throughout the specification and drawings with the same reference numerals. The drawing figures are not necessarily to scale. Certain features of the disclosure may be shown exaggerated in scale or in somewhat schematic form and some details of conventional elements may not be shown in the interest of clarity and conciseness. The present disclosure is susceptible to embodiments of different forms. Specific embodiments are described in detail and are shown in the drawings, with the understanding that the present disclosure is to be considered an exemplification of the principles of the disclosure, and is not intended to limit the disclosure to that illustrated and described herein. It is to be fully recognized that the different teachings of the embodiments discussed below may be employed separately or in any suitable combination to produce desired results. 
         [0024]    Unless otherwise specified, any use of any form of the terms “connect”, “engage”, “couple”, “attach”, or any other term describing an interaction between elements is not meant to limit the interaction to direct interaction between the elements and may also include indirect interaction between the elements described. In the following discussion and in the claims, the terms “including” and “comprising” are used in an open-ended fashion, and thus should be interpreted to mean “including, but not limited to . . . ”. The term “box” refers to an end of a length of pipe having female threads cut into the inner diameter and the term “pin” refers to an end of a length of pipe having male threads cut into the outer diameter. In addition, reference to the terms “left” and “right” are made for purposes of ease of description. The terms “pipe,” “tubular member,” “casing” and the like as used herein shall include tubing and other generally cylindrical objects. The various characteristics mentioned above, as well as other features and characteristics described in more detail below, will be readily apparent to those skilled in the art upon reading the following detailed description of the embodiments, and by referring to the accompanying drawings. 
         [0025]    Use of the concepts of the present disclosure is not limited to pipe thread connections and may find utility in other threaded connection applications, both within oilfield technology and other areas to which the concepts of the current disclosure may be applied. 
         [0026]    Referring to  FIG. 1 , torque member apparatus  100  includes an end  110  of a first tubular member, an end  120  of a second tubular member, and a torque member or torque nut  130 . In some embodiments, the end  110  is a pin end and the end  120  is a box end. In general operation, torque member  130  is threaded onto the unengaged pin end  110 , and the box end  120  is then made up onto the pin end  110 . Other manners of making up the apparatus  100  are also contemplated in accordance with the principles herein. 
         [0027]    Pin  110  includes a first threaded section having a plurality of pin male threads  112 , a pin face  114 , and a central flow passage  115 . In some embodiments, pin male threads  112  are located along a significant portion of the axial length of the outer diameter of pin end  110 , and pin face  114  is located at the terminal end of pin  110 . 
         [0028]    Box end  120  includes a second threaded section having a plurality of box female threads  122 , an inner box face  124 , an outer box face  126 , a box cavity  145 , and a central flow passage  125 . In some embodiments, box female threads  122  are located along a significant portion of the axial length of the inner diameter of the box cavity  145 , and inner box face  124  is located at the inner axial portion of the box cavity  145 . Outer box face  126  is located at the terminal end of box  120 . In some embodiments, the axial length of the first threaded section  112  is greater than the axial length of the second threaded section  122 . 
         [0029]    Torque member  130  includes a third threaded section having a plurality of torque member female threads  132 , and torque member face  134 . Torque member female threads  132  are located along the axial length of the inner diameter of torque member  130  forming the through-passage  135 . In some embodiments, the axial length of the first threaded section  112  is greater than the axial length of the third threaded section  132 . 
         [0030]      FIGS. 2-5  depict embodiments of the assembly of the torque member apparatus  100 . Referring initially to  FIG. 2 , pin  110  of torque member apparatus  100  is shown. In  FIG. 3 , torque member  130  is shown with torque member female threads  132  threaded onto pin male threads  112  of pin  110 . In certain embodiments already described, the torque member threaded section  132  includes an axial length less than the axial length of the pin threaded section  112  such that the torque member  130  can be threaded variable distances onto the pin end  110  while also leaving exposed a portion  112   a  of the pin threaded section  112 , as shown in  FIG. 3 . Consequently, there is an engaged portion  112   b  of the pin threads as well as the exposed portion  112   a.    
         [0031]    Referring now to  FIG. 4 , pin  110  and exposed threaded portion  112   a  are shown threaded into box  120  such that pin face  114  contacts inner box face  124 . This creates another engaged portion of threads  112   c  between the pin  110  and the box  120 , in addition to the reduced exposed portion  112   a  and the torque member engaged portion  112   b . In this manner, torque member  130  is spaced apart from outer box face  126  in a first, untorqued position while the pin and box ends are made up. The connection between pin  110  and box  120  is torqued to specification. 
         [0032]    Referring now to  FIG. 5 , torque member  130  is shown having been threaded back along the pin threads  112  toward outer box face  126  (after initially having been threaded onto pin  110  in the opposite direction). This eliminates the gap and the exposed threaded portion  112   a  between the torque member  130  and the outer box face  126 . In this manner, torque member face  134  is brought into contact with outer box face  126 . In some embodiments, the connection made up by torque member  130  and box  120  at the interface between torque member face  134  and outer box face  126  is torqued to specification providing a second, torqued position of the torque member  130  and completing the assembly of torque member apparatus  100 . The controlled torquing of pin  110  into box  120  and of torque member  130  onto box face  126  provides two torque loading interfaces. In this way, the torque capacity of threaded connections is greatly increased. 
         [0033]      FIGS. 6-9  depict embodiments of the disassembly of the torque member apparatus  100 . Referring initially to  FIG. 6 , the connection made up by torque member  130  and box  120  is untorqued. Torque member  130  is shown spaced apart from outer box face  126 . In  FIG. 7 , the connection made up by pin  110  and box  120  is untorqued. In  FIG. 8 , pin  110  is shown with box  120  removed and with torque member female threads  132  threaded onto pin male threads  112  of pin  110 . In  FIG. 9 , pin  110  is shown with torque member  130  unthreaded and removed, completing the disassembly of torque member apparatus  100 . 
         [0034]    Thus, in some embodiments, the moveable torque member provides a moveable shoulder that is brought into contact with the face of the second tubular for torquing purposes. In this manner, the moveable torque member provides flexibility in tolerances allowed at the torque member shoulder. A fixed shoulder provides only set tolerances and no flexibility of same. Certain embodiments include the increased torque capability of threaded connections along with predictability, repeatability and consistency in the amount of torque applied to threaded interfaces without exceeding design constraints associated with drilling operations. 
         [0035]    In other embodiments, the connection between the tubular members includes connection means other than threads, and the torque member is coupled to the end of the first tubular by means other than threads. In such embodiments, the torque member is still adapted to be moveable relative both of the connected tubulars such that it may be clamped down onto the second tubular and provide an increased torque loading capacity of the overall tubular connection. 
         [0036]    While the disclosure is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and description. It should be understood, however, that the drawings and detailed description thereto are not intended to limit the disclosure to the particular form disclosed, but on the contrary, the intention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the present disclosure.