Abstract:
A completion assembly has one or more control lines. The control lines can develop differing degrees of slack depending on the completion assembly configuration and also on the particular use of the completion assembly. A line slack compensator cooperates with the completion assembly to provide or remove slack in one or more control lines as necessary for a given operation and a given completion assembly.

Description:
This application claims the benefit of U.S. Provisional Application 60/521,767 filed on Jul. 1, 2004. 

   BACKGROUND 
   1. Field of Invention 
   The present invention pertains to a downhole completion assembly having at least one control line, and particularly to a completion assembly in which the at least one control line has at least one splice. 
   2. Related Art 
   It is often desirable to run one or more control lines in, on, or through assemblies to be placed in a well. Control lines include, but are not limited to, hydraulic conduits, electrical line conduits, and fiber optic cables. A control line is generally used to communicate in some manner with one or more tools placed in the well. For example, a packer placed downhole may be set by hydraulic fluid pressure communicated from the surface to an actuator mechanism of the packer. Alternatively, a fiber optic cable may be pumped through a control line and used, for example, to measure the temperature profile of the well, or communicate a command to a tool downhole. 
   Control lines can be comprised of two or more segments. Those segments are typically (but not always) joined at the surface. Using segments may require the control line to have one or more splice. Once assembled, the control line is typically attached to the tubular or completion assembly being run into the well and the combined tubular or completion assembly and control line are run in the well together. 
   SUMMARY 
   The present invention provides for a completion assembly having a line slack compensator to provide or remove slack in a control line. 
   Advantages and other features of the invention will become apparent from the following description, drawings, and claims. 

   
     BRIEF DESCRIPTION OF DRAWINGS 
       FIG. 1  is a schematic view illustrating a line slack compensator constructed in accordance with the present invention. 
       FIGS. 2A-2C  is a schematic view illustrating an alternate embodiment of a line slack compensator constructed in accordance with the present invention. 
       FIG. 3  is a perspective view of a ring used in the embodiment of the line slack compensator of  FIGS. 2A-2C . 
       FIG. 4  is a schematic view of a completion assembly incorporating a line slack compensator constructed in accordance with the present invention. 
       FIG. 5A  is a schematic view of a line slack compensator constructed in accordance with the present invention. 
       FIG. 5B  is a schematic view of a component of the line slack compensator of  FIG. 5A . 
       FIG. 6A  is a schematic view of a line slack compensator constructed in accordance with the present invention. 
       FIG. 6B  is a schematic view of a component of the line slack compensator of  FIG. 6A . 
       FIG. 7A  is a schematic view of a line slack compensator constructed in accordance with the present invention. 
       FIG. 7B  is a schematic view of a component of the line slack compensator of  FIG. 7A . 
       FIG. 8  is a schematic view of a line slack compensator constructed in accordance with the present invention. 
       FIG. 9  is a schematic view of a line slack compensator constructed in accordance with the present invention. 
   

   DETAILED DESCRIPTION 
   Referring to  FIG. 1 , a line slack compensator  10  comprises a coiled control line section  12  and a straight control line section  14 . Control line sections  12 ,  14  include, but are not limited to, hydraulic conduits, electrical line conduits, and fiber optic cables conduits. Fiber optic cable conduits include conduits having one or more fiber optic strands pumped therethrough or pre-packaged fiber optic strands housed in a self-contained protective covering. Straight control line section  14  can be above or below coiled control line section  12 , or both. Coiled control line section  12  comprises coils  16  that can expand or contract to allow or take up slack, as desired. 
   Coiled control line section  12  is carried on a mandrel  18 . An upper slider sleeve  20  or a lower slider sleeve  22 , or both, are also carried on mandrel  18  and engage coils  16  with slots  24 . Mandrel  18  may have threads on its outer surface complementary to threads on the inner surfaces of sleeves  20 ,  22  so sleeves  20 ,  22  can be axially displaced along mandrel  18  when sleeves  20 ,  22  are rotated relative to mandrel  18 . Alternatively, the outer surface of mandrel  18  and the inner surface of sleeves  20 ,  22  may be smooth to allow sliding displacement of sleeves  20 ,  22  along mandrel  18 . A protective sleeve  26  covers at least coiled control line section  12  and protects it from damage. Slider sleeves  20 ,  22  can be releasably fixed to mandrel  18 , for example, by set screws. Those set screws or other fixing means are accessed through openings in protective sleeve  26 . Guide lines may be provided to assist alignment. 
   A possible assembly method includes attaching mandrel  18  to a top sub  28 . Upper slider sleeve  20  is installed on mandrel  18 . Coiled control line section  12  is placed on mandrel  18  and upper slider sleeve  20  is spun down to engage coils  16 . Preferably a few turns of coils  16  are positioned above upper slider sleeve  20 . The upper portion of straight control line section  14  is joined to the upper portion of coiled control line  12  to allow fluid communication therethrough. 
   Lower slider sleeve  22  is installed on mandrel  18  and spun onto coiled control line  12  with slots  24  engaging coils  16 . Preferably a few turns of coils  16  are positioned below lower slider sleeve  22 . Protective sleeve  26  is mounted over coiled control line section  12  and slider sleeves  20 ,  22 , for example, by joining it to top sub  28 . Set screws, locking bolts, or other fixing means are passed through openings in protective sleeve  26  and releasably secure slider sleeves  20 ,  22  to mandrel  18 . The lower portion of straight control line  14  is joined to the lower portion of coiled control line  12  to allow fluid communication therethrough. A bottom sub  30  may be joined to the lower end of mandrel  18 . 
   In operation, say to provide slack at the lower end of line slack compensator  10 , the set screws (fixing means) holding lower slider sleeve  22  to mandrel  18  are loosened sufficiently to allow lower slider sleeve  22  to be moved downward. As lower slider sleeve  22  moves downward, coils  16  are stretched, producing slack at the lower end of line slack compensator  10 . To remove the slack, lower slider sleeve  22  is displaced upward to compress coils  16 . The extra coils below lower slider sleeve  22  compensate if the full slack provided is not all returned. Slack at the upper end of line slack compensator  10  is achieved in the same manner using upper slider sleeve  20 . 
   An alternate embodiment of a line slack compensator  100  is shown in  FIGS. 2A-2C . In this embodiment, rings  102  are used to provide or remove slack. Preferably three rings  102  are used, but the invention may have more or fewer rings  102 , as desired. For ease of discussion, an embodiment using three rings  102  is discussed below. 
   In the embodiment shown, each ring  102  has at least one longitudinal or axially-directed hole  104  running through the sidewall  106  of ring  102 , as shown in  FIG. 3 . Hole  104  may have some curvature as it passes through sidewall  106 . Ring  102  also has at least one radially-directed hole  108  through sidewall  106 . Rings  102  are carried on a mandrel  110 . Upper and lower rings  102  are fixed to mandrel  110  with holes  104  aligned. Middle ring  102  is free to rotate on mandrel  110 . Hole  108  can be used to allow access to mandrel  118  to releasably secure ring  102  to mandrel  110 . For example, hole  108  may have threads to receive a set screw. 
   Control line  112  is fed through holes  104 . When holes  104  of each ring  102  are aligned, slack is provided. While slack is provided, splicing operations may be performed with control line  112 . To remove slack, middle ring  102  is turned in either direction, wrapping control line  112  around mandrel  110 . Once the desired amount of slack is removed, middle ring  102  can be fixed to mandrel  110 . Using more rings  102  will permit management of larger amounts of slack in control line  112 . 
   Although rings  102  are described as having holes  104  therethrough, control line  112  can also be clamped or otherwise secured to ring  102  so as to rotate with ring  102 . For example, the embodiment of line slack compensator  10  shown in  FIG. 5A  has a curved groove  300  on ring  302  in which control line  112  is carried.  FIG. 5B  shows an enlarged view of ring  302  and groove  300 . If desired, a strap could be placed over control line  112  once placed in groove  300  to protect and restrain control line  112 . 
   Similarly, in  FIG. 6A  a catch  304  is shown releasably mounted on mandrel  110 . Catch  304  preferably has a curved nose  306  with a channel  308  to carry control line  112  without inducing undue bending stress in control line  112 .  FIG. 6B  shows an enlarged view of catch  304 . 
     FIG. 7A  shows yet another embodiment of line compensator  10  in which a hook  310  is used to capture control line  112  and remove slack therefrom. Hook  310  is removably mounted on mandrel  110  and has a curved end  312  to snare control line  112 .  FIG. 7B  shows an enlarged view of hook  310 . 
   In  FIG. 8 , an alternate arrangement of catches  304  is shown. In this embodiment, catches  304  are longitudinally and radially misaligned or offset. Control line  112  is laced or woven around catches  304  to remove slack therefrom.  FIG. 9  shows a similar arrangement in which catches  304  are longitudinally staggered around the circumference of mandrel  110 . Control line  112  is again interlaced or interwoven around catches  304  to take up or remove slack therefrom. Many other variations are possible and within the scope of this invention. 
   Referring to  FIG. 4 , line slack compensator  10  can be incorporated into a completion assembly  210  comprising a contraction joint  212 , a line slack compensator  10 , a make-up sub  216 , and a stinger  218 . In the embodiment shown, a fiber optic cable  220 , having at least one splice, extends from the surface to stinger  218 . 
   When assembled and ready to be run into the well, contraction joint  212  is joined to line slack compensator  10 , line slack compensator  10  is joined to make-up sub  216 , and make-up sub  216  is joined to stinger  218 . 
   An assembly method includes joining stinger  218  and make-up sub  216  and placing that combination in the rotary. In the embodiment shown, a lower free end of fiber optic cable  220  extends from the stinger/make-up sub combination. Contraction joint  212  and line slack compensator  10  are joined and that combination is stabbed or otherwise joined to the stinger/make-up sub combination, preferably without rotation of either combination. An upper free end of fiber optic cable  220  extends from the contraction joint/line slack compensator combination. 
   The upper and lower free ends of fiber optic cable  220  must be spliced together before assembly  210  can be run into the well. If slack is need, it may be obtained from line slack compensator  10 . Once the splice is made, slack is removed by line slack compensator  10 . If desired, a splice of fiber optic cable  220  can also be made between contraction joint  212  and line slack compensator  10 . Line slack compensator  10  can provide or remove slack at its upper and lower ends. 
   Line slack compensator  10  is able to provide or remove slack by extension or contraction of various turns of fiber optic cable  220  wrapped around a mandrel  18  in line slack compensator  10 . Movement of those loosely wrapped coils allows extension or contraction similar to that of a coil spring. 
   Make-up sub  216  is a tool well known in the art, and is sometimes referred to as a “quick connect” or “make-up union”. It comprises upper and lower halves with a clutch interface to transmit torque when the two halves are joined. The two halves are stabbed together and the collar (and only the collar) is rotated to secure the two halves together. 
   Although only a few exemplary embodiments of this invention have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of this invention.