Abstract:
The present invention generally relates to a connector for coiled tubing that resists torque developed by rotating downhole equipment. The connector couples to an inside diameter of the coiled tubing and can use a torque ring that rotationally locks the connector to the coiled tubing. Additionally, the connector can have a slot on an outside diameter thereof adapted to receive a weld bead on the inside diameter of the coiled tubing in order to rotationally lock the connector to the coiled tubing.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention generally relates to connectors for use with tubular members. More particularly, the present invention relates to a connector for use with coiled tubing that connects to an inside of the coiled tubing and provides torque resistance.  
           [0003]    2. Description of the Related Art  
           [0004]    Hydrocarbon wells typically involve wellbores that extend from the earth&#39;s surface to a selected depth in order to intersect a hydrocarbon bearing formation. Therefore, the wellbores can be several thousand feet in depth. Since tools must be lowered into the wellbore quickly and efficiently, drilling, completion, and production operations often utilize coiled tubing to support the tools used in operations performed within the wellbore instead of jointed pipe or jointed tubing. Therefore, tools connected to the end of coiled tubing include various kinds of downhole equipment tools, bottom hole assemblies, stabilizers, drill motors, and bits. Often times, the coiled tubing must be run through wellbores with restrictions or within other tubulars having a relatively small inside diameter such as production tubing. Therefore, smaller diameter connections between the coiled tubing and the downhole equipment prevent the connections from becoming stuck at a restriction. By engaging the downhole tool to the inside diameter of the coiled tubing instead of the coiled tubing&#39;s outside diameter, U.S. Pat. No. 5,251,695 discloses a connector with a smaller outside diameter.  
           [0005]    The ability of the connector to withstand torque is important. If the connector is allowed to spin freely, the downhole equipment runs a high risk of failure. Additionally, rotation between the coiled tubing and downhole equipment can result in the downhole equipment disconnecting from the coiled tubing. The connector in U.S. Pat. No. 5,251,695 fails to withstand torque transmitted to the connection by rotating downhole equipment. U.S. Pat. No. 6,056,051 discloses a slip assembly providing a configuration of rotationally locked slips with wickers to promote resistance of applied torque. However, this connection requires preventing rotation of the slip assembly and internally locking the connector to the slip assembly in order to prevent rotation.  
           [0006]    In the manufacturing of coiled tubing, the coiled tubing is initially a flat piece of metal that is formed into a tubular shape and welded. This process forms a weld bead that typically must be removed from the inside diameter prior to connecting to the coiled tubing. However, removing the weld bead takes time and removes a portion of the coiled tubing that can provide rotational resistance.  
           [0007]    Therefore, there is a need for an improved apparatus that couples downhole equipment to a segment of coiled tubing and also resists the torque that occurs as a result of rotating downhole equipment.  
         SUMMARY OF THE INVENTION  
         [0008]    A connector for coiled tubing is disclosed that resists torque developed by rotating downhole equipment. The connector couples to an inside diameter of the coiled tubing and can use a torque ring that rotationally locks the connector to the coiled tubing. Additionally, the connector can have a slot on an outside diameter thereof adapted to receive a weld bead on the inside diameter of the coiled tubing in order to rotationally lock the connector to the coiled tubing. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]    So that the manner in which the above recited features of the present invention can be understood in detail, a more particular description of the invention, 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 invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments.  
         [0010]    [0010]FIG. 1 is a sectional view of an embodiment of a connector.  
         [0011]    [0011]FIG. 2 is a sectional view of the connector coupled to a portion of coiled tubing.  
         [0012]    [0012]FIG. 3 is a view of a torque ring on the connector engaged with an end of the coiled tubing.  
         [0013]    [0013]FIG. 4 is a view of the connector with a fishing neck partially inserted in the portion of coiled tubing. 
     
    
     DETAILED DESCRIPTION  
       [0014]    Referring to FIG. 1, the connector  100  comprises a mandrel  102 , a sleeve  104 , a torque ring  106 , a slip  108  positioned between a lower slip cone  110  and an upper slip cone  112 , a packer  114 , and a fishing neck  116 . A first end  118  of the mandrel  102  comprises a threaded portion  120  that can be used to attach a downhole tool (not shown) such as a mud motor or any assembly of tools. The fishing neck  116  attached to a second end  122  of the mandrel  102  receives an end portion of coiled tubing (not shown). The mandrel  102  extends through the sleeve  104  so that a relative movement between the mandrel  102  and the sleeve  104  radially expands the slip  108  and places the packer  114  in compression. A thread  124  connects the sleeve  104  to the mandrel  102  and allows the ability to provide the relative movement between the mandrel  102  and the sleeve  104 .  
         [0015]    The torque ring  106  circumscribes the mandrel  102  adjacent a lower shoulder  126  created by an end of the sleeve  104 . A locking assembly (not shown) such as a slot in the torque ring  106  and a key in the mandrel  102  aligns in order to rotationally lock the torque ring  106  to the mandrel  102 . The torque ring  106  comprises a series of teeth  128 . Both the lower slip cone  110  and the upper slip cone  112  circumscribe the mandrel  102  adjacent the slip  108  and have a wedge shape with inclined surface  111  and inclined surface  113 , respectively. Initially, the slip  108  is in an unexpanded position since the slip  108  is positioned proximate a portion of the upper slip cone  112  having a smaller outside diameter and a portion of the lower slip cone  110  having a smaller outside diameter. An outside diameter of the slip  108  can have formations  109  that grip an inside surface of the coiled tubing (See FIG. 2) to prevent axial movement between the connector  100  and the coiled tubing. The slip  108 , upper slip cone  112 , and lower slip cone  110  compose a slip assembly  107 ; however, any slip assembly  107  design that prevents axial movement between the connector  100  and the coiled tubing is within the scope of the invention. As shown, the packer  114  circumscribes the mandrel  102  between an upper shoulder  130  created by an end of the fishing neck  116  and a packing ring  132  adjacent the upper slip cone  112 . Alternatively, the packer  114  can be positioned around the mandrel  102  between the slip assembly  107  and the torque ring  106 . Preferably, the packer  114  is an elastomeric material that can have a smooth outside diameter surface or an outside diameter surface with formations.  
         [0016]    As shown in FIG. 1, the connector  100  can include the packing ring  132  and a round retaining ring  134  that circumscribe the mandrel  102  between the upper slip cone  112  and the packer  114 . The packing ring  132  translates axial movement from the upper slip cone  112  and provides a surface for contacting an edge of the packer  114 . Since a portion of the retaining ring  134  contacts a preformed profile  136  around an outside diameter of the mandrel  102 , axial movement of the retaining ring  134  relative to the mandrel  102  is limited to a length of the preformed profile  136 . A portion of the retaining ring  134  also contacts a shoulder  138  on the upper slip cone  112  in order to prevent axial movement of the upper slip cone  112  past the retaining ring  134 .  
         [0017]    [0017]FIG. 2 and FIG. 3 illustrate the connector  100  connected to an end portion of coiled tubing  200 . However, the connector  100  can be used to connect to an end of any tubing used in a wellbore such as a pipe or any tubular section. As shown, the connector  100  has an outside diameter with no portion substantially greater than an outside diameter of the coiled tubing  200 . An end  202  of the coiled tubing  200  is advanced over the fishing neck  116  and the mandrel  102  until the end  202  contacts the torque ring  106 . Once the end  202  contacts the torque ring  106 , the sleeve  104  is rotated relative to the mandrel  102  in order to axially move the sleeve  104  with respect to the mandrel  102 . Therefore, the lower shoulder  126  formed by the end of the sleeve moves axially with respect to the mandrel  102  pushing the torque ring  106  axially in order to engage the teeth  128  of the torque ring  106  with the end  202  of the coiled tubing  200 . Engaging the teeth  128  with the end  202  of the coiled tubing  200  provides frictional contact between the teeth  128  and the end  202 . Preferably, the teeth  128  at least partially deform the end  202  of the coiled tubing  200  when the teeth  128  engage the end  202 . Alternatively, the teeth  128  can embed into or penetrate the metal forming the end  202  of the coiled tubing  200  when the teeth  128  engage the end  202 . Once the teeth  128  engage the end  202  of the coiled tubing  200 , the teeth  128  prevent rotational movement between the coiled tubing  200  and the connector  100 . Since the torque ring  106  is rotationally locked to the mandrel  102  of the connector  100 , the connector  100  transfers torque from downhole tools (not shown) to the coiled tubing  200  through the torque ring  106  that resists rotational movement.  
         [0018]    At the same time as the teeth  128  engage the end  202  of the coiled tubing  200 , the axial movement of the torque ring  106  caused by the rotation of the sleeve  104  forces the lower slip cone  110  to move axially along the mandrel  102 . Since the sleeve  104  moves axially with respect to the mandrel  102 , the lower shoulder  126  formed by the end of the sleeve moves axially closer to the upper shoulder  130  that is stationary relative to the mandrel  102 . Therefore, the inclined surface of the lower slip cone  110  forces under the slip  108 , the inclined surface  113  of the upper slip cone  112  forces under the slip  108 , and the packer  114  compresses outward due to a decrease in axial space between the upper shoulder  130  and the packing ring  132 . As a result, the outside diameter of the slip  108  contacts an inside diameter  204  of the coiled tubing  200  preventing axial movement between the connector  100  and the coiled tubing  200 . The slip  108  can have a C-shape with a longitudinal gap that allows the slip  108  to expand radially as the slip  108  moves up the inclined surfaces  111 ,  113  to a portion of the slip cones  110 ,  112  having a larger outside diameter. Once the retaining ring  134  is prevented from further movement along the length of the mandrel  102  due to the preformed profile  136 , the upper slip cone  112  is prevented from further axial movement relative to the mandrel  102 . Therefore, this limits the axial movement of the packing ring  134  in order to prevent damage to the packer  114  while allowing further compression of the slip assembly  107  since the lower shoulder  126  continues to move closer to the upper slip cone  112  that is held stationary relative to the mandrel  102  by its interaction with the retaining ring  134 . Compression of the packer  114  causes the outside diameter of the packer  114  to compress against the inside diameter  204  of the coiled tubing  200  in order to seal an annulus between the inside diameter  204  and the connector  100 . The packer  114  can seal an irregular inside diameter  204  of the coiled tubing  200  when compressed. Once the sleeve  104  has been rotated during the operation of the connector  100 , a set screw  206  can be advanced to rotationally lock the sleeve  104  to the mandrel  102 .  
         [0019]    Furthermore, FIG. 4 illustrates a slot  400  machined along the length of the fishing neck  116  that provides additional resistance against torque between the connector  100  and the coiled tubing  200 . The slot  400  receives a weld bead  402  on the inside diameter  204  of the coiled tubing  200  as the coiled tubing  200  advances onto the connector  100 . Therefore, the slot  400  allows the fishing neck  116  to slide inside the coiled tubing  200  as it cradles the weld bead  402  to prevent rotation of the coiled tubing  200 . Thus, the weld bead  402  acts as a stop once it contacts the slot  400 . The slot  400  may additionally be machined to extend through the slip  108 , the upper slip cone  112 , and the lower slip cone  110  (as shown in phantom) so that the weld bead  402  is cradled throughout the length of the coiled tubing  200  that is positioned around the connector  100 . If the coiled tubing  200  design does not include a weld bead  402  (for example, because it was removed in manufacturing), the connector  100  still resists torque through the function of the torque ring  106  acting alone. On the other hand, the slot  400  on the fishing neck  116  when keyed to the weld bead  402  can resist torque acting alone if the connector  100  does not include a torque ring  106 .  
         [0020]    Coupling a downhole tool to coiled tubing can be accomplished in a method utilizing the connector  100  as described in FIG. 1 through FIG. 4. Establishing a connection that prevents rotational and axial movement between the downhole tool and the coiled tubing  200  can include positioning the connector  100  proximate the coiled tubing  200 , aligning a slot  400  on an outside diameter of the connector  100  with a weld bead  402  on an inside diameter  204  of the coiled tubing  200 , engaging teeth  128  of a torque ring  106  with an end  202  of the coiled tubing  200 , expanding a slip assembly  107  into contact with the inside diameter  204  of the coiled tubing  200 , and connecting the downhole tool to a threaded portion  120  of the connector  100 . As a result, the downhole tool is coupled to the coiled tubing  200  by the connector  100 .  
         [0021]    While the foregoing is directed to embodiments of the invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.