Abstract:
A coiled tubing assembly includes coiled tubing having a side wall that defines an opening and an insert covering the opening and affixed to the coiled tubing. The coiled tubing has a longitudinal axis. The insert defines a capillary window therethrough. The opening and the insert include ends that are non-perpendicular to the longitudinal axis. A method of making a coiled tubing assembly includes providing coiled tubing defining a side wall opening and pulling a capillary tube into the interior of the coiled tubing through the side wall opening. The method further includes attaching the capillary tube to a capillary window of an insert for covering the side wall opening and affixing the insert to the coiled tubing.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority from U.S. Provisional Application 61/246,815, filed on Sep. 29, 2009, which is incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to coiled tubing used in oilfield operations. 
         [0004]    2. Description of Related Art 
         [0005]    Information concerning, for example, the temperatures and pressures exhibited within a wellbore is used to predict the production interval of the well. Knowledge of the production interval is used to enhance the recovery rate of a well and, in turn, make the well more economical to operate. Tools exist to retrieve such information relating to conventional wells that exhibit temperatures below about 204° C. (400° F.). In wells that exhibit higher temperatures, such as steam assisted gravity drainage (SAGD) wells, cyclic steam wells, and the like, design of such tools becomes difficult, as elastomer materials often cannot withstand such high temperatures. 
         [0006]    Other downhole devices have been constructed to measure characteristics, such as temperature and pressure, within a wellbore. For example, one such conventional device employs a coiled tubing in which a plurality of capillary tubes is disposed. Some of the plurality of capillary tubes have temperature sensors disposed therein, while others of the plurality of capillary tubes are used to measure pressure. In high temperature applications, however, such coiled tubing devices are susceptible to failure due to fatigue. 
         [0007]    There are devices for measuring characteristics, such as pressure and temperature, in a downhole environment that are well known in the art, however, considerable shortcomings remain. 
       BRIEF SUMMARY OF THE INVENTION 
       [0008]    In one aspect, the present invention provides a coiled tubing assembly. The coiled tubing assembly includes a coiled tubing having a side wall that defines an opening and an insert covering the opening and affixed to the coiled tubing. The coiled tubing has a longitudinal axis. The insert defines a capillary window therethrough. The opening and the insert include ends that are non-perpendicular to the longitudinal axis. 
         [0009]    In another aspect, the present invention provides a method of making a coiled tubing assembly. The method includes providing a coiled tubing defining a side wall opening and pulling a capillary tube into an interior of the coiled tubing through the side wall opening. The method further includes attaching the capillary tube to a capillary window of an insert for covering the side wall opening and affixing the insert to the coiled tubing. 
         [0010]    The present invention provides significant advantages, including increasing fatigue life of coiled tubing assemblies over conventional coiled tubing assemblies. Additional objectives, features and advantages will be apparent in the written description which follows. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    The novel features characteristic of the invention are set forth in the appended claims. However, the invention itself, as well as a preferred mode of use, and further objectives and advantages thereof, will best be understood by reference to the following detailed description when read in conjunction with the accompanying drawings, in which the leftmost significant digit(s) in the reference numerals denote(s) the first figure in which the respective reference numerals appear, wherein: 
           [0012]      FIG. 1  is a top, plan view of an illustrative embodiment of a coiled tubing assembly; 
           [0013]      FIG. 2  is a top, plan view of the coiled tubing assembly of  FIG. 1 , wherein an insert of the coiled tubing assembly is displaced from an opening of a coiled tubing of the coiled tubing assembly; 
           [0014]      FIG. 3  is a cross-sectional view of the coiled tubing assembly of  FIG. 1 , taken along the line  3 - 3  in  FIG. 1 , wherein the insert of the coiled tubing assembly is displaced from the opening of the coiled tubing of the coiled tubing assembly; 
           [0015]      FIG. 4  is an enlarged view of a portion of the insert of the coiled tubing assembly of  FIG. 1  including a first end thereof; 
           [0016]      FIG. 5  is an enlarged view of a portion of the insert of the coiled tubing assembly of  FIG. 1  including a second end thereof; 
           [0017]      FIG. 6  is an enlarged view of a portion of the coiled tubing of the coiled tubing assembly of  FIG. 1  including a first end of the opening in the coiled tubing; 
           [0018]      FIG. 7  is an enlarged view of a portion of the coiled tubing of the coiled tubing assembly of  FIG. 1  including a second end of the opening in the coiled tubing; 
           [0019]      FIG. 8A  is a cross-sectional view of the coiled tubing assembly of  FIG. 1 , taken along the line  8 A- 8 A in  FIG. 1 , depicting an illustrative configuration of the coiled tubing assembly prior to welding; 
           [0020]      FIG. 8B  is a cross-sectional view of the coiled tubing assembly of  FIG. 1 , corresponding to the view of  FIG. 8A , depicting an illustrative configuration of the coiled tubing assembly after welding; 
           [0021]      FIG. 9A  is a cross-sectional view of the coiled tubing assembly of  FIG. 1 , taken along the line  9 A- 9 A in  FIG. 1 , depicting an illustrative configuration of the coiled tubing assembly prior to welding; 
           [0022]      FIG. 9B  is a cross-sectional view of the coiled tubing assembly of  FIG. 1 , corresponding to the view of  FIG. 9A , depicting an illustrative configuration of the coiled tubing assembly after welding; 
           [0023]      FIG. 10A  is a cross-sectional view of the coiled tubing assembly of  FIG. 1 , taken along the line  10 A- 10 A in  FIG. 1 , depicting an illustrative configuration of the coiled tubing assembly prior to welding; 
           [0024]      FIG. 10B  is a cross-sectional view of the coiled tubing assembly of  FIG. 1 , corresponding to the view of  FIG. 10A , depicting an illustrative configuration of the coiled tubing assembly after welding; 
           [0025]      FIG. 11  is a cross-sectional view of the coiled tubing assembly of  FIG. 1 , taken along the line  11 - 11  in  FIG. 1 ; 
           [0026]      FIG. 12  is a cross-sectional view of the coiled tubing assembly of  FIG. 1 , taken along the line  12 - 12  in  FIG. 1 ; 
           [0027]      FIG. 13  is a cross-sectional view of an illustrative embodiment of an assembled coiled tubing assembly corresponding to the view of  FIG. 3 , except that the insert of the coiled tubing assembly is not displaced from the opening of the coiled tubing of the coiled tubing assembly; 
           [0028]      FIGS. 14 and 15  are top, plan views of alternative, illustrative embodiments of the insert of the coiled tubing assembly of  FIG. 1 ; 
           [0029]      FIG. 16  is a cross-sectional view, corresponding to the view of  FIG. 3 , illustrating a method for assembling the coiled tubing assembly of  FIG. 1  and depicting devices useful in the practice of the method; 
           [0030]      FIGS. 17 and 18  are end, elevational views of an illustrative embodiment of a secondary pulling tool of  FIG. 16 ; 
           [0031]      FIG. 19  is a cross-sectional view of the secondary pulling tool of  FIG. 16 , taken along the line  19 - 19  in  FIG. 17 ; 
           [0032]      FIG. 20  is a cross-sectional view of the secondary pulling tool of  FIG. 16 , taken along the line  20 - 20  in  FIG. 19 ; 
           [0033]      FIG. 21  is a perspective view of portions of the coiled tubing and capillary tube of  FIG. 16 , illustrating an exemplary use of an illustrative embodiment of a capillary tube guide; 
           [0034]      FIG. 22  is an end, elevational view of the capillary tube guide of  FIG. 21 ; 
           [0035]      FIG. 23  is a top, plan view of the capillary tube guide of  FIG. 21 ; 
           [0036]      FIG. 24  is an end, elevational view of the capillary tube guide of  FIG. 21 ; and 
           [0037]      FIG. 25  is a cross-sectional view, corresponding to the view of  FIG. 16 , illustrating a method for assembling the coiled tubing assembly of  FIG. 1  and depicting a device useful in the practice of the invention. 
       
    
    
       [0038]    While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and are herein described in detail. It should be understood, however, that the description herein of specific embodiments is not intended to limit the invention to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the scope of the invention as defined by the appended claims. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0039]    Illustrative embodiments of the invention are described below. In the interest of clarity, not all features of an actual implementation are described in this specification. It will be appreciated that in the development of any such actual embodiment, numerous implementation-specific decisions must be made to achieve the developer&#39;s specific goals, such as compliance with system-related and business-related constraints, which will vary from one implementation to another. Moreover, it will be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking for those of ordinary skill in the art having the benefit of this disclosure. 
         [0040]    The present invention relates to a coiled tubing assembly comprising a coiled tubing having an opening in which an insert is affixed. The insert defines a capillary window in which a capillary tube is affixed. The capillary tube is used in the measurement of various downhole conditions, such as temperature, pressure, or the like. 
         [0041]      FIGS. 1-3  depict various views of an illustrative embodiment of a coiled tubing assembly  101  configured to be operatively associated with a capillary tube, such as a capillary tube  1301  shown in  FIG. 13 , and associated devices for measuring conditions, such as temperature, pressure, and the like, that exist downhole in oilfield operations.  FIG. 1  depicts a top, plan view of coiled tubing assembly  101 .  FIG. 2  depicts a top, plan view of coiled tubing assembly  101 , in which an insert  103  is displaced from an opening  105  in a coiled tubing  107 .  FIG. 3  is a cross-sectional view, taken along the line  3 - 3  in  FIG. 1 , in which insert  103  is displaced from opening  105  in coiled tubing  107 . 
         [0042]    In the embodiment illustrated in  FIGS. 1-3 , coiled tubing assembly  101  comprises coiled tubing  107  defining opening  105  in a side wall  109  thereof. Coiled tubing assembly  101  further comprises insert  103  affixed in opening  105 , such as by a weldment or the like, to isolate an interior of coiled tubing  107  from an environment about coiled tubing  107 . Opening  105  and insert  103  incorporate particular features that inhibit fatigue-related failure of such coiled tubing assemblies, as are discussed in greater detail herein. 
         [0043]    Referring in particular to  FIG. 2 , insert  103  includes a first side  201  and a second side  203  that extend generally parallel to a longitudinal axis  205  of coiled tubing  107 . Insert  103  further includes a first end  207  and a second end  209  that are angled at non-right angles with respect to first side  201  and second side  203 .  FIG. 4  is an enlarged, top, plan view of first end  207  of insert  103  and  FIG. 5  is an enlarged, top, plan view of second end  209  of insert  103 . As best shown in  FIGS. 4 and 5 , respectively, first end  207  is angled with respect to first side  201  and second side  203  by an angle A, while second end  209  is angled with respect to first side  201  and second side  203  by an angle B. It should be noted that angle A may be the same as or different from angle B. In the illustrated embodiment, angles A and B are generally about 30 degrees, although the present invention contemplates many other angles A and B. For example, in various embodiments of the present invention, angles A and B may be within a range of about 15 degrees to about 70 degrees; however, the scope of the present invention is not so limited. First end  207  meets first side  201  at a first transition  211  and second end  209  meets second side  203  at a second transition  213 . First transition  211  defines a radius R 1  and second transition  213  defines a radius R 2 . Note that radius R 1  may be the same as or different from radius R 2 . In the illustrated embodiment, radius R 1  and radius R 2  are greater than about 3 millimeters. It should be noted that radius R 1  and radius R 2  are preferably not so large as to cause angles A and B, respectively, to be outside of the range of about 15 degrees to about 70 degrees. 
         [0044]    Referring again to  FIG. 2 , opening  105  defined by coiled tubing  107  comprises a first side  215  and a second side  217  that extend generally parallel to longitudinal axis  205  of coiled tubing  107 . As best shown in  FIG. 6 , which is an enlarged, top, plan view of a portion of opening  105 , opening  105  further includes a first end  219  that is angled at angle A with respect to first side  215 , i.e., generally corresponding to angle A of insert  103 . Referring to  FIG. 7 , which is an enlarged, top plan view of a portion of opening  105 , opening  105  further includes a second end  221  that is angled at angle B with respect to second side  217 , i.e., generally corresponding to angle B of insert  103 . First end  219  meets first side  215  at a first transition  223  and second end  221  meets second side  217  at a second transition  225 . First transition  223  of opening  105  exhibits generally the same radius R 1  as first transition  211  of insert  103 . Second transition  225  of opening  105  exhibits generally the same radius R 2  as second transition  213  of insert  103 . 
         [0045]    Referring again to  FIG. 2 , coiled tubing  107  defines a chamfer  227  about opening  105 . Insert  103  defines a chamfer  229  along first end  207  of insert  103 . Insert  103  further defines a chamfer  231  along second end  209  of insert  103 . When insert  103  is mated with coiled tubing  107  in opening  105 , as shown in  FIG. 1 , chamfers  227 ,  229 , and  231  form joints between insert  103  and coiled tubing  107  where insert  103  is welded and joined to coiled tubing  107 . For example, as shown in  FIG. 8A , which is a cross-sectional view taken along the line  8 A- 8 A in  FIG. 1 , a joint  801  extends along and between first sides  201  and  215  and exhibits an included angle C. A joint  803  extends along and between second sides  203  and  217  and exhibits an included angle D. It should be noted that angle C may correspond to or be different than angle D. Preferably, angles C and D are at least 45 degrees, to allow full weld penetration. As shown in  FIG. 8B , which is a view corresponding to that of  FIG. 8A , insert  103  is joined to coiled tubing  107  by weldments  805  and  807  where joints  801  and  803 , respectively, existed prior to weldments  805  and  807  being generated. 
         [0046]    Similarly, as shown in  FIG. 9A , which is a cross-sectional view taken along the line  9 A- 9 A in  FIG. 1 , a joint  901  extends along and between first end  207  of insert  103  and first end  219  of opening  105  and exhibits an included angle E. Similarly, joint  1001  extends along and between second end  209  of insert  103  and second end  221  of opening  105  and exhibits an included angle F, as shown in  FIG. 10A , which is a cross-sectional view taken along the line  10 A- 10 A in  FIG. 1 . Note that angle E may correspond to or be different than angle F. Preferably, angles E and F are about 90 degrees to allow full weld penetration and to inhibit fatigue-related failure of coiled tubing assembly  101 . As shown in  FIG. 9B , which is a view corresponding to  FIG. 9A , insert  103  is joined to coiled tubing  107  by weldment  903  where joint  901  existed prior to weldment  903  being generated. As shown in  FIG. 10B , which is a view corresponding to  FIG. 10A , insert  103  is joined to coiled tubing  107  by weldment  1003  where joint  1001  existed prior to weldment  1003  being generated. 
         [0047]      FIG. 11  is a cross-sectional view taken along the line  11 - 11  in  FIG. 1 , while  FIG. 12  is a cross-sectional view taken along the line  12 - 12  in  FIG. 1 . Referring in particular to  FIGS. 3 ,  11 , and  12 , insert  103  includes a fitting  301  that defines a capillary window  111  (shown only in  FIGS. 3 and 11 ) communicating between an interior of coiled tubing assembly  101  and an environment external to coiled tubing assembly  101 . Fitting  301  and capillary window  111  are also shown in  FIGS. 8A and 8B . As shown in  FIG. 13 , capillary tube  1301  is received in capillary window  111  such that an environment external to coiled tubing assembly  101  is communicated via capillary window  111  to capillary tube  1301 . Capillary tube  1301  is used in the measurement of various characteristics of the environment external to coiled tubing assembly  101 , such as temperature, pressure, or the like. For example, capillary tube  1301  may convey pressure, corresponding to the pressure of the environment external to coiled tubing assembly  101 , to a pressure sensor that may be located inside coiled tubing  107  or proximate a wellhead at a surface of a well. Capillary window  111  may be configured to allow a pressure test fixture, a screen, a burst plug, or the like to be fitted to capillary window  111 . 
         [0048]    As discussed herein, opening  105  of coiled tubing  107  and insert  103  incorporate particular features that inhibit fatigue-related failure of such coiled tubing assemblies. Generally, fatigue cracks tend to propagate radially in coiled tubing, i.e., generally circumferentially about the coiled tubing perpendicular to a longitudinal axis of the coiled tubing, such as longitudinal axis  205  of coiled tubing  107 . Weldments reduce fatigue life and tend to fail along heat affected zones adjacent weldments where the material of the coiled tubing is more brittle. Thus, axial weldments, i.e., weldments that are generally parallel to a longitudinal axis of the coiled tubing, such as longitudinal axis  205  of coiled tubing  107 , perform better than radial weldments. As shown in at least  FIG. 2 , ends  207  and  209  of insert  103  and ends  219  and  221  of opening  105  are configured to be non-perpendicular to longitudinal axis  205  of coiled tubing  107 , so that the heat affected zones adjacent weldments  903  (shown in  FIG. 9B) and 1003  (shown in  FIG. 10B ) are not aligned with a plane of crack propagation. Such configurations inhibit the likelihood of crack initiation and propagation in coiled tubing assembly  101  and increase the fatigue life of coiled tubing assembly  101 . Moreover, referring to  FIG. 3 , insert  103  tapers from greater thicknesses proximate fitting  301  to thinner thicknesses proximate first end  207  and second end  209 . Fitting  301  is also preferably thinner, rather than thicker. These features allow fitting  301  to be more flexible and to reduce the amount of heat needed to generate weldments  805  and  807  (shown in  FIG. 8B ) proximate fitting  301 . 
         [0049]    It should be noted that the present invention is not limited to the particular shape of insert  103  depicted in the drawings. For example, an insert for the present coiled tubing assembly may exhibit shapes such as those depicted in  FIGS. 14 and 15 . In the embodiment of  FIG. 14 , an insert  1401  includes a first end  1403  and a second end  1405  that exhibit semi-circular shapes. In the embodiment of  FIG. 15 , an insert  1501  includes a first end  1503  and a second end  1505  that exhibit angular shapes having central apexes  1507  and  1509 , respectively. Generally, other aspects of inserts  1401  and  1501  correspond to the aspects of insert  103 , shown in at least  FIG. 1 . Irrespective of the particular shape of the insert, the opening defined by the coiled tubing, e.g., opening  105  of coiled tubing  107 , exhibits the same general shape as the insert used with the coiled tubing to make up the coiled tubing assembly. It should be noted that the present invention contemplates various shapes for insert  103  and opening  105  of coiled tubing  107  other than the shapes shown in the figures. 
         [0050]    Coiled tubing assembly  101  may include one insert and corresponding capillary tube, such as insert  103  and capillary tube  1301 , or coiled tubing assembly  101  may include many inserts and corresponding capillary tubes. While there are many ways to assemble coiled tubing assembly  101 ,  FIGS. 16-25  depict one particular method of assembling coiled tubing assembly  101  and associated devices used in the method. It should be noted that, while the description herein relates to coiled tubing assembly  101  including insert  103 , the description applies equally to any insert contemplated by the present invention. 
         [0051]    Referring to  FIG. 16 , coiled tubing  107  is provided with opening  105 . A primary pulling tool  1601  with a first pulling cable  1603  attached to a fore end  1605  thereof is disposed within coiled tubing  107 . A second pulling cable  1607  is attached to an aft end  1609  of primary pulling tool  1601  and is attached through a first clip  1611  of a secondary pulling tool  1613 . A capillary tube  1615 , which corresponds to capillary tube  1301 , is attached to a second clip  1617  of secondary pulling tool  1613 . As primary pulling tool  1601  is advanced through coiled tubing  107 , generally in a direction corresponding to arrow  1619 , capillary tube  1615  is pulled into coiled tubing  107  from a spool  1621 . At the next opening of coiled tubing  107 , another secondary pulling tool  1613  is attached to second pulling cable  1607  via first clip  1611  thereof, so that another capillary tube may be pulled into coiled tubing  107 . 
         [0052]      FIGS. 17-20  depict an illustrative embodiment of secondary pulling tool  1613 .  FIG. 17  is an end, elevational view of secondary pulling tool  1613 , taken generally in a direction corresponding to arrow  FIG. 17  in  FIG. 16 .  FIG. 18  is an end, elevational view of secondary pulling tool  1613 , taken generally in a direction corresponding to arrow  FIG. 18  in  FIG. 16 .  FIG. 19  is a cross-sectional view of secondary pulling tool  1613 , taken along the line  19 - 19  in  FIG. 17 .  FIG. 20  is a cross-sectional view of secondary pulling tool  1613 , taken along the line  20 - 20  in FIG.  19 . Secondary pulling tool  1613  comprises a body  1701  defining a first bore  1703  that extends into and terminates in body  1701  from a first end  1705  thereof. Body  1701  further defines a second bore  1801  that extends into body  1701  from a second end  1803  thereof and terminates at a side surface  2001  of body  1701 , extending through side surface  2001 . Capillary tube  1615  is received in first bore  1703  and is retained therein by one or more fasteners  1901 , which may be in the form of set screws. Second pulling cable  1607  is received in second bore  1801  and is retained therein by one or more fasteners  1903 , which may also be in the form of set screws. 
         [0053]    In one embodiment, as depicted in  FIG. 21 , a capillary tube guide  2101  is disposed on opening  105  of coiled tubing  107  to protect capillary tube  1615  from damage by contact with the edges of opening  105  after secondary pulling tool  1613  is received within coiled tubing  107 .  FIGS. 22-25  depict various views of an exemplary embodiment of capillary tube guide  2101 .  FIG. 22  is an end, elevational view of capillary tube guide  2101  taken generally in a direction corresponding to arrow  FIG. 22  of  FIG. 23 .  FIG. 23  is a top, plan view of capillary tube guide  2101 , while  FIG. 24  is an end, elevational view of capillary tube guide  2101  taken generally in a direction corresponding to arrow  FIG. 24  of  FIG. 23 .  FIG. 25  depicts a cross-sectional view of capillary tube guide  2101 , taken along line  25 - 25  in  FIG. 23 , along with a view of coiled tubing  107  corresponding to the view of  FIG. 16 . Capillary tube guide  2101  comprises a first leg  2201  and a second leg  2203  extending from a base  2205 . First leg  2201 , second leg  2203 , and base  2205  define a slot  2303 , through which capillary tube  1615  passes when capillary tube guide  2101  is in use. As best shown in  FIGS. 22 and 25 , portions of first leg  2201 , second leg  2203 , and base  2205  that define slot  2303  are rounded, curved, radiused, or the like to inhibit damage to capillary tubing  1615  when capillary tube guide  2101  is in use. In the illustrated embodiment, a protrusion  2207  extends from a lower surface  2209  of capillary tube guide  2101  that interfaces with opening  105  of coiled tubing  107  to position capillary tube guide  2101  properly with respect to coiled tubing  107 . 
         [0054]    The particular embodiments disclosed above are illustrative only, as the invention may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. Therefore, no limitations are intended to the details of construction or design herein shown, other than as described in the claims below.