Abstract:
A technique facilitates joining of coiled tubing sections. A framework has one or more movable stands with features designed to grip and manipulate an end of a coiled tubing section. The ability to hold and selectively move an end of a coiled tubing section or the ends of both coiled tubing sections enables an operator to easily prepare the coiled tubing ends and to couple the coiled tubing ends with a coiled tubing connector.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]     The present document is based on and claims priority to U.S. provisional application Ser. No. 60/720,832, filed Sep. 27, 2005. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The present invention relates to joining sections of coiled tubing. More specifically, the present invention relates to an assembly skid for connecting two segments of coiled tubing. Once the segments of coiled tubing are held in the assembly skid, the coiled tubing can be prepared for the installation of a connector and then secured to the connector.  
       BACKGROUND  
       [0003]     When performing coiled tubing services, if the amount of coiled tubing required to perform the service cannot be contained on a single reel as one continuous length of pipe, two or more sections of coiled tubing must be joined together. The joining of sections of coiled tubing can be necessitated, for example, by the lift capacity of handling equipment or the volume capacity of the work reel.  
         [0004]     However, there are limited mechanisms and techniques that have been developed for gripping and handling sections of coiled tubing to facilitate connection of the coiled tubing sections. Accordingly, the formation of coiled tubing connections can be difficult, costly and time-consuming.  
       SUMMARY  
       [0005]     In general, the present invention provides a system and a methodology for gripping and manipulating sections of coiled tubing to facilitate the formation of a connection between the sections of coiled tubing. A framework is provided with one or more vise stands having features designed to grip and manipulate the end of a coiled tubing section. This ability enables an operator to easily and consistently prepare and move ends of coiled tubing sections into engagement with a coiled tubing connector. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0006]     Certain embodiments of the invention will hereafter be described with reference to the accompanying drawings, wherein like reference numerals denote like elements, and:  
         [0007]      FIG. 1  illustrates an embodiment of a spoolable connector installation skid and a shipping container, according to an embodiment of the present invention;  
         [0008]      FIG. 2  is generally a side view of the spoolable connector installation skid illustrated in  FIG. 1 ;  
         [0009]      FIG. 3  is top view of the spoolable connector installation skid illustrated in  FIG. 2 ;  
         [0010]      FIG. 4  is an orthogonal view of a rounding/machining fixture for preparation of a coiled tubing end, according to an embodiment of the present invention;  
         [0011]      FIG. 5  is a side view of two coiled tubing sections held by the spoolable connector installation skid for movement into engagement, according to an embodiment of the present invention;  
         [0012]      FIG. 6  is a side view similar to that of  FIG. 5  but showing the two coiled tubing sections connected together, according to an embodiment of the present invention and  
         [0013]      FIG. 7  is an orthogonal view of a fixture for deforming the ends of the coiled tubing sections to secure engagement with the coiled tubing connector, according to an embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION  
       [0014]     In the following description, numerous details are set forth to provide an understanding of the present invention. However, it will be understood by those of ordinary skill in the art that the present invention may be practiced without these details and that numerous variations or modifications from the described embodiments may be possible.  
         [0015]     The present invention relates to a system and methodology for connecting sections of coiled tubing. The need for connecting one segment of coiled tubing to another segment of coiled tubing arises, for example, when the required length of coiled tubing for a given application cannot be contained on a single reel as one continuous length of pipe. The required length of coiled tubing may be too great due to limited volume capacity of the work reel or limited lift capacity of the handling equipment. An assembly or installation skid is used in retrieving sections of coiled tubing from separate reels. The skid also is used to grip and manipulate the ends of each coiled tubing section to facilitate connection of the coiled tubing ends with an appropriate coiled tubing connector.  
         [0016]     Referring generally to  FIG. 1 , an embodiment of the present invention is illustrated. In this embodiment, a skid  20  is designed as a spoolable connector installation skid able to greatly facilitate the handling and connection of separate sections of coiled tubing. In the embodiment illustrated, skid  20  is housed within a shipping container  22  and mounted within a protective cage  24 . The protective cage  24  may be covered with a protective layer, such as corrugated siding, to protect the work area and skid  20  from the elements at a given well site location. The skid  20  also may be mounted on extensible legs  26  sized to enable movement of skid  20  between a position fully enclosed within shipping container  22  and a position above shipping container  22 , as illustrated. The extensible legs  26  may be powered by one or more lifting mechanisms, such as hydraulic cylinders  28 , that enable selective movement of skid  20  between the enclosed transport position and the raised operational position. Once shipping container  22  is moved to an appropriate well site, skid  20  can be elevated above the shipping container  22 , via hydraulics cylinders  28 , for use in connecting sections of coiled tubing.  
         [0017]     With additional reference to  FIG. 2 , further details of one embodiment of skid  20  can be described. In this embodiment, skid  20  is a spoolable connector assembly skid having at least one vise stand  30 . As illustrated, two vise stands  30  may be mounted to a framework  32  having, for example, a base section  34  and side sections  36 . The vise stands  30  are pivotably mounted to framework  32  to facilitate alignment with the coiled tubing sections to be connected. In the specific embodiment illustrated, vise stands  30  are pivotably mounted about generally vertical axes, and each vise stand is designed to rotate through a desired angular span, such as plus or minus 30° about its generally vertical axis.  
         [0018]     A vise  38  is mounted to each vise stand  30  to enable secure gripping of a section of coiled tubing once directed into engagement with the vise  38 . In the illustrated example, a pair of vises  38  is mounted to each vise stand  30  to further secure a section of coiled tubing that is to be connected to an adjacent section of coiled tubing. A coiled tubing fairlead  40  also is mounted to each vise stand  30  and is designed to guide the section of coiled tubing to the corresponding vise or vises  38 . Each coiled tubing fairlead  40  is movably mounted to its corresponding vise stand  30  to enable manipulation of the coiled tubing end as it is brought into engagement with the corresponding vise  38 . By way of example, each coiled tubing fairlead  40  may be pivotably mounted to its vise stand  30  and controlled by an actuator  42 , such as a hydraulic cylinder. In the specific embodiment illustrated, each coiled tubing fairlead  40  is pivotably mounted to its vise stand  30  for pivoting motion about a generally horizontal axis when moved by the extension and contraction of actuator  42 . The rotatability of each vise stand  30  about its generally vertical axis allows the coiled tubing fairlead  40  and the coiled tubing vises  38  to be aligned with a section of coiled tubing being pulled to skid  20  from its coiled tubing reel.  
         [0019]     Additionally, one or both of the vise stands  30  is translatable to facilitate the actual coupling of coiled tubing sections with a coiled tubing connector once the pair of coiled tubing sections are securely gripped by vises  38 . In the embodiment illustrated, one of the vises  30  (the rightmost vise  30  in  FIG. 2 ) is linearly translatable generally along a line that moves the vise stand  30  either toward or away from the adjacent vise stand  30 . The translatable vise stand  30  may be mounted to a translatable vise sled  43  selectively movable along a corresponding track  44  formed in framework  32 . The translating and pivoting motion of one or more vise stands  30  as well as the pivoting motion of coiled tubing fairleads  40  can be controlled via a hydraulic control system  46 . The hydraulic system  46  and other controllable features of skid  20  may be controlled via an overall system control  48  positioned remotely from skid  20 . Overall system control  48  provides appropriate inputs to the skid through, for example, an umbilical connection  50  or through a wireless connection.  
         [0020]     Skid  20  also may comprise a winch  52  for pulling coiled tubing into engagement with coiled tubing fairleads  40  and vises  38 . As discussed in greater detail below, winch  52  can be coupled to a section of coiled tubing via an appropriate pull line routed through, for example, a cable fairlead  54 . The action of winch  52  also can be controlled remotely via system control  48 .  
         [0021]     As illustrated best in  FIG. 3 , a pull line  56 , such as a cable or wire, is routed from winch  52  and through cable fairlead  54  which is mounted to base section  34  of framework  32 . The pull line  56  is further routed through a series of snatch blocks  58  mounted to framework  32  in a manner to pull a coiled tubing section  60  onto skid  20  from a remotely located coiled tubing reel. The path along which pull line  56  travels is routed through the coiled tubing fairlead  40  mounted on the pivoting vise stand  30  closest to the coiled tubing reel from which the coiled tubing section  60  is drawn.  
         [0022]     When the coiled tubing section  60  is pulled through the coiled tubing fairlead  40  and an end  62  of the coiled tubing is moved adequately past the corresponding vise  38 , the vise stand  30  is rotated to align the coiled tubing with the appropriate vise  38 . The corresponding coiled tubing fairlead  40  is then moved, e.g. pivoted about its horizontal axis, via extension or contraction of actuator  42  to manipulate the coiled tubing section into proper engagement with the adjacent vise or vises  38 . Rollers  64  may be rotatably mounted at opposed ends of each coiled tubing fairlead  40 . The rollers  64  are designed and located to engage the coiled tubing section  60  and to move the coiled tubing section into a bottom half  66  of the vises  38 . A top half  68  of each vise  38  is then placed over the top of the coiled tubing section  60  and secured to firmly grip the coiled tubing section. The top half  68  and bottom half  66  of vises  38  may be joined by appropriate fasteners, such as bolts. When a corresponding coiled tubing section is moved onto the opposed vise stand, a similar procedure is used to draw the corresponding coiled tubing section from a remote reel, to manipulate it via the corresponding coiled tubing fairlead, and to secure the corresponding coiled tubing section via the corresponding vise or vises.  
         [0023]     In the embodiment illustrated, each vise stand  30  uses a plurality of vises  38 , e.g. two vises  38 , to provide redundant clamping of the section of coiled tubing. Once the section of coiled tubing is securely gripped by vises  38 , a cable clamp  70  is released to disconnect the pull line  56  from the section of coiled tubing. At this point, the snatch blocks  58  can be repositioned to enable the corresponding section of coiled tubing to be pulled onto an opposite side of skid  20  from a second coiled tubing reel.  
         [0024]     Once each section of coiled tubing is securely gripped or clamped in its set of vises  38 , the sections of coiled tubing and the coiled tubing ends to be connected can be manipulated freely on each vise stand  30 . This facilitates the preparation of each coiled tubing end for engagement with a coiled tubing connector and also allows the ends of the coiled tubing sections to be easily aligned for connection.  
         [0025]     To prepare coiled tubing ends, e.g. coiled tubing end  62 , for connection to the coiled tubing connector, a variety of procedures can be performed. For example, the interior and/or exterior of the coiled tubing end can be rounded, machined, chamfered, deformed, ground or otherwise prepared to facilitate the formation of a dependable connection. According to one procedural embodiment, the coiled tubing is initially cut perpendicular to the axis of the tubing. Then, a rounding fixture  72 , such as the rounding fixture illustrated in  FIG. 4 , is attached to the end of the coiled tubing section by a rounding clamp  74 . The inside diameter of rounding clamp  74  is sized such that when the clamp is completely closed over the end of the coiled tubing, the coiled tubing wall is stressed beyond a yield point. When the clamp  74  is removed, the tubing expands elastically a small amount but remains round at its original diameter. The rounding clamp  74  may be transitioned to its closed position by tightening a plurality of bolts  76  extending between halves of the rounding clamp. The bolts can be tightened appropriately with a manual torque wrench or an air or hydraulic torque wrench having a gear reduction drive.  
         [0026]     After attaching rounding clamp  74  to an end of the section of coiled tubing, the inside diameter of the coiled tubing is machined. For example, a standard shell reamer tool appropriately sized for the coiled tubing connector can be installed on a rotatable shaft  78  of fixture  72 . In this embodiment, shaft  78  has a standard machine tool taper  79  designed for mating engagement with a conventional shell reamer. The shaft  78  may be rotated by hand or with an air or hydraulic drill or ratchet. As the shell reamer is turned, a fixture lead screw  80  is rotated and advances shaft  78  and the shell reamer into an interior of the coiled tubing. This machining action cuts the inside diameter of the coiled tubing to the correct bore diameter for engagement with a coiled tubing connector. The shell reamer is advanced until the bore is machined to the required depth, and then removed from the coiled tubing. Upon removal of the shell reamer, a chamfering tool is placed on the machine tool taper  79  of shaft  78 . The coiled tubing is then chamfered as desired for the specific type of spoolable coiled tubing connector. The rounding clamp  74  is then removed, and an air or hydraulic powered honing device can be run into the machine bore of the coiled tubing to finish the machining process. Of course, a variety of other end conditioning procedures can be incorporated into preparation of the coiled tubing for engagement with a coiled tubing connector.  
         [0027]     Upon finalizing preparation of the coiled tubing end or ends, a spoolable, coiled tubing connector is engaged with one end of the coiled tubing, as illustrated in  FIG. 5 . Although other types of coiled tubing connectors can be used, the illustrated example comprises a coiled tubing connector  82  having a radially expanded center region  84  and radially smaller insertion portions  86  that are each sized for insertion into the appropriately prepared coiled tubing end. The insertion portions  86  may be designed with a variety of retention mechanisms to enable secure connections between the coiled tubing connector and the corresponding sections of coiled tubing. For example, each insertion portion  86  may comprise one or more recesses  87  into which the coiled tubing ends are deformed. The recesses may be machined into each insertion portion and may comprise grooves, dimples, or other recesses into which each coiled tubing end is plastically deformed to secure the connection.  
         [0028]     Also, the center region  84  may be constructed with a diameter similar or the same as the diameter of the sections of coiled tubing to be joined. Using the same or similar diameter facilitates spoolability of the connector and coiled tubing. In the embodiment illustrated, end  62  of coiled tubing section  60  is to be joined with a corresponding coiled tubing end  88  of a corresponding section of coiled tubing  90  via coiled tubing connector  82 .  
         [0029]     The coiled tubing sections  60  and  90  are securely gripped and held by their corresponding vises  38 . Accordingly, upon insertion of coiled tubing connector  82  into one of the coiled tubing ends  62  or  88 , one or both of the vise stands are rotated until the sections of coiled tubing are aligned. Once aligned, the translating vise stand  30  is moved via translating vise sled  42  toward the opposite vise stand  30 . The relative movement of the vise stands toward each other is continued until the second half of coiled tubing connector  82  is fully engaged, as illustrated in  FIG. 6 .  
         [0030]     Once the two ends of the spoolable coiled tubing connector  82  are fully inserted into ends  62  and  88  of the sections of coiled tubing  60  and  90 , respectively, the connection may be secured. As further illustrated in  FIG. 6 , connection of the coiled tubing section to coiled tubing connector  82  can be secured by plastically deforming the ends of the coiled tubing sections into corresponding recesses  87  on the insertion portions  86  of the coiled tubing connector  82 . For example, a plurality of depressions  92  can be pressed into the exterior of coiled tubing ends  62  and  88  to form internally directed protrusions positioned to match corresponding recesses  87 , thereby securing the coiled tubing sections to the coiled tubing connector.  
         [0031]     A fixture  94  can be used to form the properly positioned protrusions, e.g. dimples. One example of such a fixture is illustrated in  FIG. 7 . In this embodiment, fixture  94  comprises a screw type dimpling fixture having separable housing portions  96  that may be released from each other or secured together by appropriate fasteners, such as bolts  98 . Each housing portion  96  has an arcuate interior shaped to clamp against an end of the coiled tubing when bolts  98  are tightened. Once tightened against the coiled tubing in the proper orientation, a plurality of dimpling screws  100  are tightened to deform the coiled tubing material inwardly into corresponding recesses  87 . The dimpling screws  100  can be turned with, for example, hand tools, air or hydraulic ratchets, air or hydraulic torque wrenches with gear reduction drives or other tightening tools. Additionally, fixture  94  can be designed with an appropriate guide pin or other type of guide feature positioned to mate with a corresponding guide feature located on the coiled tubing or coiled tubing connector. The guide features ensure that fixture  94  is properly positioned such that rotation of dimpling screws  100  deforms the coiled tubing into the recesses  87  formed in the coiled tubing connector. After securing one section of coiled tubing to the coiled tubing connector  82 , bolts  98  are loosened and fixture  94  is moved to the opposite side of coiled tubing connector  82 . The bolts  98  are again tightened, and dimpling screws  100  are rotated to deform the opposite section of coiled tubing into corresponding recesses formed in connector  82 .  
         [0032]     Fixture  94  can be formed in a variety of configurations with many types of deformation mechanisms designed to deform the coiled tubing as necessary to interfere with recesses of various sizes and shapes within the coiled tubing connector  82 . Additionally, the fixture  94  can be designed as a longer fixture that spans both sides of coiled tubing connector  82 . In this latter embodiment, all of the dimples or other deformations can be formed with a single attachment of the fixture  94  rather than moving the fixture from one side of the coiled tubing connector to the other.  
         [0033]     The shape and configuration of components used to grip, manipulate and prepare the sections of coiled tubing for connection can be changed depending on the desired application. Also, other components can be added or interchanged as necessary to facilitate specific coiled tubing connection applications. The size and strength of various components also can be adjusted depending on, for example, the length and diameter of the coiled tubing sections being combined.  
         [0034]     Accordingly, although only a few embodiments of the present invention have been described in detail above, those of ordinary skill in the art will readily appreciate that many modifications are possible without materially departing from the teachings of this invention. Such modifications are intended to be included within the scope of this invention as defined in the claims.