Abstract:
A technique enables extending the useful life of tubing deployed in a wellbore. The technique involves routing a damaged or distorted tubing through a straightening device. The tubing straightening device bends and counter bends the tubing along predetermined axes as it passes through the tubing straightening device. The bending and counter bending are selected so the tubing exits the straightening device with a predetermined form.

Description:
BACKGROUND 
       [0001]    The statements in this section merely provide background information related to the present disclosure and may not constitute prior art. In many types of well related operations, various types of tubing are deployed downhole into a wellbore. Smaller diameter tubing, e.g. control lines, may be used in conjunction with larger diameter tubing, e.g. production or coiled tubing. For example, control lines may be deployed within or along a coiled tubing string to facilitate the transmission of signals along the wellbore. In some applications, control lines utilize a carrier tubing for enclosing a signal carrier, such as an optical fiber. However, many of these types of tubing are susceptible to being bent or otherwise deformed during operations and/or during movement into and out of the wellbore. If sufficiently bent or otherwise damaged, the tubing may not be available for reuse. 
       SUMMARY 
       [0002]    In general, the present disclosure provides a system and method for extending the useful life of tubing deployed in a wellbore. Initially, a damaged or distorted tubing is selected, and the tubing is routed through a straightening device. The tubing straightening device bends and counter bends the tubing along predetermined axes as it passes through the tubing straightening device. The bending and counter bending are selected so the tubing exits the straightening device with a predetermined form, e.g. a straightened form. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0003]    Certain embodiments of the invention will hereafter be described with reference to the accompanying drawings, wherein like reference numerals denote like elements, and: 
           [0004]      FIG. 1  is a schematic illustration of one embodiment of a tubing straightening device; 
           [0005]      FIG. 2  is a schematic illustration similar to that of  FIG. 1  but with additional features; 
           [0006]      FIG. 3  is a schematic representation of a bending regimen useful in straightening certain types of tubing; 
           [0007]      FIG. 4  is an illustration of one embodiment of a straightening station wheel acting on tubing passing through the tubing straightening device; and 
           [0008]      FIG. 5  is a flowchart providing one example of a procedure which may be employed to straighten tubing with the tubing straightening device. 
       
    
    
     DETAILED DESCRIPTION 
       [0009]    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. 
         [0010]    The present disclosure generally relates to a system and method for extending the useful life of certain types of tubing employed in downhole applications. For example, the technique enables returning control line tubing, e.g. fiber carrier tubing, to a form which allows continued use in subsequent downhole applications. In many well related operations, deployment and use of tubing downhole creates bends or other distortions in the tubing, and those distortions can be substantially removed by employing the methodology described herein. 
         [0011]    In one embodiment, a tubing straightening device is used to return a distorted length of tubing to its original shape by re-straightening the distorted length of tubing. The technique may be designed to correct many types of distortions in several types of tubing, e.g. control line tubing. One embodiment employs the tubing straightening device to straighten optical fiber carrier tubing, such as fiber carrier tubing formed from Inconel™ or from a variety of other materials, including other metal tubing materials. Once straightened, the fiber carrier tubing can be reinjected into a coiled tubing string and reused as opposed to purchasing a new spool of fiber carrier tubing for injection into the coiled tubing string. 
         [0012]    According to one application, the tubing straightening device comprises a series of stations mounted along a rigid chassis. Each of the stations is designed to bend the tubing in a direction along a predetermined axis as the tubing is moved through the tubing straightening device. In one specific embodiment, the series of stations comprises a series of roller or wheel sets which subject the tubing to a sequence of bending cycles and cause the tubing to straighten before exiting the tubing straightening device. The series of wheel sets may comprise a series of four wheel sets which bend and counter bend the tubing along two distinct axes, e.g. a Y-axis and an X-axis. The wheel sets are adjustable to bend and counter bend the tubing in the desired sequence of directions regardless of how the tubing enters the tubing straightening device. In some applications, the final two wheel sets are employed to “set the bend” which results in a straight tube upon exit. 
         [0013]    Referring generally to  FIG. 1 , one embodiment of a system  20  for straightening a tubing  22  is illustrated. In this embodiment, system  20  comprises a tubing straightening device  24  which returns the tubing  22  to a desired form as the tubing  22  is passed through device  24 . By way of example, tubing  22  enters the tubing straightening device  24  as a distorted, e.g. bent, tubing (as represented by reference character  26 ) and exits tubing straightening device  24  in a desired form, e.g. a straight tube (as represented by reference character  28 ). The tubing  22  may be control line tubing, such as a communication line carrier. In one embodiment, tubing  22  is a small diameter communication line carrier in the form of an optical fiber carrier tubing. 
         [0014]    In the embodiment illustrated, tubing straightening device  24  comprises a chassis  30  having a tubing inlet  32  through which tubing  22  enters and a tubing outlet  34  through which tubing  22  exits the tubing straightening device. Tubing straightening device  24  further comprises a plurality of stations  36  which are designed to manipulate the tubing  22  in a manner that removes the undesired distortions, e.g. bends and/or remove local deformations on the tubing  22 . The number, arrangement and type of stations  36  can be altered according to the type of tubing  22  being reconditioned. However, in one embodiment of the tubing straightening device  24 , the stations  36  each comprise a roller or wheel set  38 . 
         [0015]    Each wheel set  38  comprises a plurality of wheels  40  through which tubing  22  is passed. The wheels  40  are positioned to bend the tubing  22  to a desired degree and in a desired direction. The desired bending at each sequential wheel set  38  may be achieved by forming at least one of the wheels  40  as an adjustable wheel  42  while the other wheels  40  are mounted in a stationary position on chassis  30 . In the illustrated embodiment, the desired bending is achieved at each wheel set  38  by utilizing one adjustable wheel  42  which acts on the tubing  22  between two stationary wheels  40  as the tubing  22  is passed through that specific wheel set  38 . 
         [0016]    The adjustable wheel  42  may be moved toward or away from the cooperating stationary wheels  40  to apply a greater or lesser bending force for reconditioning the tubing  22 . Movement of each adjustable wheel  42  may be accomplished by a corresponding actuator  44  which may be a manual or powered actuator. In one example, each actuator  44  is a mechanical actuator, such as a ball and screw actuator or a stepper motor actuator. 
         [0017]    In the embodiment illustrated in  FIG. 1 , the actuators  44  are oriented in different directions relative to each other to apply desired bending forces to the tubing  22 , via wheels  42 , in corresponding directions. By way of example, the actuators  44  and wheel sets  38  may be positioned to enable bending and counter bending of the tubing  22  along a plurality of different axes. In the specific example illustrated, tubing  22  moves into the first station  36  and a bending force is applied to the tubing  22  in a direction along a first axis. From the first station  36 , the tubing  22  is directed through a second station  36  which applies a bending force to the tubing  22  in a direction along a second axis, e.g. a perpendicular axis. From the second station  36 , the tubing  22  is directed to a third station  36  which applies a counter bending force to the tubing  22  in an opposite direction along the first axis. Subsequently, the tubing  22  is directed from the third station to a fourth station  36  which applies a counter bending force to the tubing  22  in an opposite direction along the second axis. In this example, the sequential and controlled bending of tubing  22  creates a straight tube which exits tubing straightening device  24  through tubing outlet  34 . 
         [0018]    Movement of tubing  22  through tubing straightening device  24  may be facilitated by a feeder mechanism  46 , as illustrated in  FIG. 2 . The feeder mechanism  46  is employed to guide the deformed tubing  26  into tubing inlet  32  of tubing straightening device  24 . A puller mechanism  48  also may be used to provide a pulling force which helps move tubing  22  through tubing straightening device  24 . In some applications, actuators  44  may be in the form of automated actuators controlled by a control system  50 . For example, control system  50  may be a processor based control system which may be programmed to automatically adjust the actuators  44  to apply desired bending forces to the tubing  22  at each sequential station  36 . 
         [0019]    In one specific embodiment, the tubing  22  undergoes bending and counter bending in directions along both a Y-axis and an X-axis, as illustrated in  FIG. 3 . In this embodiment, the distorted tubing, e.g. distorted carrier tubing, is fed into tubing straightening device  24  through tubing inlet  32  and routed through the first wheel set  38 . The first wheel set bends the tubing  22  in a direction along the −Y axis relatively aggressively, as represented by arrow  52 . This bending action pre-forms the tubing  22  in the −Y axis direction, thereby removing any opposing Y axis residual bend it may have had before entering tubing straightening device  24 . The bending at the first wheel set  38  pre-shapes the Y-axis of the tubing  22 . 
         [0020]    Subsequently, tubing  22  is routed through the second wheel set  38  between the adjustable and stationary wheels  40 . The second wheel set bends the tubing  22  in a direction along the −X axis relatively aggressively, as represented by arrow  54 . This bending action pre-forms the tubing  22  in the −X axis direction, removing any opposing X axis residual bend it may have had before entering tubing straightening device  24 . 
         [0021]    The tubing  22  is then routed through the third wheel set  38 , which is oriented and adjusted to counter bend tubing  22  in a direction along the +Y axis, as represented by arrow  56 . The tension or bending force applied by the third wheel set  38  may be somewhat less than applied by the first and second wheel sets  38 . Because the residual bend of the tubing  22  is known at this point in the tubing straightening device  24 , the tension/bending force applied by the third wheel set  38  is selected to neutralize the Y axis residual bend of the tubing  22 . 
         [0022]    After leaving the third wheel set  38 , tubing  22  is routed through the fourth wheel set  38 , which is oriented and adjusted to counter bend tubing  22  in a direction along the +X axis, as represented by arrow  58 . The tension or bending force applied by the fourth wheel set  38  also may be somewhat less than applied by the first and second wheel sets  38 . Because the residual bend along this axis of the tubing  22  also is known at this point in the tubing straightening device  24 , the tension/bending force applied by the fourth wheel set  38  is selected to neutralize the X axis residual bend of the tubing  22 . As a result, a straightened tubing  22  or  28  having a generally linear form is delivered through tubing outlet  34 . The operation of the stations  36  and/or wheel sets  38  of straightening device  24  also advantageously removes local deformations from the tubing  22 . The straightened tubing can be reinjected into coiled tubing or otherwise reused in a downhole application. 
         [0023]    Although a variety of wheels, e.g. rollers, and other devices may be used to apply desired bending forces to tubing  22  in directions along predetermined axes, one embodiment of a suitable wheel  40  is illustrated in  FIG. 4 . In this embodiment, each wheel  40  comprises a circumferential groove  60  along its face. Groove  60  is sized to receive tubing  22  and, in some applications, maybe slightly larger than the tubing  22  being straightened (or being returned to another desired form). The groove  60  aids in maintaining the tubing  22  in a desired alignment during the straightening process. 
         [0024]    One or more of the wheels  40  also may be used in cooperation with a shaping mechanism  62 , such as a shaping wheel. The shaping mechanism  62  works in concert with the wheel  40  to provide a desired cross-sectional shape to the tubing  22 . For example, the shaping mechanism  62  may be in the form of a wheel having a shaping groove  64  to correct any undesired ovality of the tubing  22 . If, for example, the tubing  22  has been deformed to an undesirable oval shape, the tubing  22  may be passed along or through an appropriate shaping mechanism  62  to return the tubing  22  to a more circular cross-sectional shape. In some applications, the shaping mechanism  62  works in cooperation with one or more of the wheels  40 , or is constructed as a separate opposing wheel set, to provide sufficient force for reshaping the tubing  22  and returning it toward its original round shape. 
         [0025]    Referring generally to the flowchart of  FIG. 5 , one example of an operational procedure for straightening tubing, e.g. fiber carrier tubing, is illustrated. In this particular embodiment, a control line tubing  22 , such as a fiber carrier tubing, is initially selected for straightening, as represented by block  66 . The tubing  22  is then fed into straightening device  24  through tubing inlet  32 , as represented by block  68 . The tubing is moved through the first station  36  and is bent in a first direction along a first axis, as represented by block  70 . 
         [0026]    The tubing  22  is then routed through the second station  36  which bends the tubing in a second direction along a second axis, as represented by block  72 . As the tubing continues to move through straightening device  24 , it is routed through the third station  36  which counter bends the tubing in an opposite direction along the first axis, as represented by block  74 . Similarly, the tubing  22  is passed through the fourth station  36  which also counter bends the tubing but in an opposite direction along the second axis, as represented by block  76 . After the fourth station, the tubing  22  is discharged through tubing outlet  34  as a straightened tubing for reuse, as represented by block  78 . 
         [0027]    The tubing straightening device  24  may be employed to recondition and remove local deformations from a variety of tubing types for use in many well related applications. The tubing straightening device  24  is particularly amenable for use in straightening and/or removing location deformations from relatively small tubes of formable material, e.g. metallic material. For example, control lines are often formed of metal with relatively small diameters, e.g. diameters equal to or less than 0.25 inch. Fiber carrier tubing often is formed from materials that may be shaped, e.g. metal materials and metal alloys, e.g. Inconel™, having small diameters of, for example, less than 0.10 inch. In some applications, the straightening device  24  also may be employed to reconditioned tubes having larger diameters. 
         [0028]    Additionally, tubing straightening device  24  may be constructed in alternate configurations depending on various factors, such as tubing size, tubing material, type of distortion, and desired finished form. For example, the number of stations mounted along the chassis may be adjusted to accommodate the reconditioning requirements of a given tubing. Wheels or other mechanisms may be employed to provide the bending forces used to bend the tubing along desired axes as the tubing moves through the straightening device. The tubing also may undergo bending/counter bending in negative and/or positive directions along two or more axes. Various feeders and pulling mechanisms may be used in combination with the straightening device to enable controlled movement of the tubing through the straightening device. Additionally, various types of mechanical and/or automated actuators may be used to apply the desired bending forces to the tubing at each station. In many applications, the applied bending force varies between stations and is selected according to the types of tubing and types of distortions being reconditioned. 
         [0029]    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.