Patent Abstract:
The present invention provides for a cutting device and associated method to cut one or more downhole control lines such that the cut ends of the one or more control lines will not interfere with subsequent fishing operations.

Full Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims the benefit of U.S. Provisional Application No. 60/486,834, filed Jul. 7, 2003. 
     
    
     BACKGROUND OF INVENTION  
       [0002]     1. Field of Invention  
         [0003]     The present invention relates to the field of cutting tools, particularly to a device and method to cut a control line downhole in a well.  
         [0004]     2. Related Art  
         [0005]     With the advent of intelligent completions, running multiple control lines downhole along completions equipment is common practice. Unfortunate occurrences sometimes require cutting the downhole tubing to retrieve the completion equipment. In those cases, the control lines can complicate the retrieval operations if the control lines are pulled apart above the tubing cut. Ideally, the control lines are cut below the tubing cut to recover as much of the control lines as possible and leave a clean “fish” downhole.  
         [0006]     Prior systems use a “splice sub” in which the control lines are anchored above and below the tubing cutting target length. A tubing cutter such as an Explosive Jet Cutter (EJC) is run to target depth and detonated to cut the tubing. Excess impact from the EJC at least partially cuts the control lines. When the tubing is removed, the control lines, if not completed severed, break at the damaged area, leaving the remaining control line portions in the vicinity of the remaining tubing. The remaining tubing is more easily “fished” if it is clear of control line remnants.  
       SUMMARY OF INVENTION  
       [0007]     The present invention provides for a cutting device and associated method to cut one or more downhole control lines such that the cut ends of the control lines will not interfere with subsequent fishing operations. 
     
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0008]      FIG. 1  shows an exploded perspective view of a cutting tool constructed in accordance with the present invention.  
         [0009]      FIG. 2  shows a cross-sectional view of an eccentric embodiment of the cutting tool of  FIG. 1 .  
         [0010]      FIG. 3  shows a first sectional view of the cutting tool of  FIG. 2 .  
         [0011]      FIG. 4  shows a second sectional view of the cutting tool of  FIG. 2 .  
         [0012]      FIG. 5  shows a cross-sectional view of a concentric embodiment of the cutting tool of  FIG. 1 .  
         [0013]      FIG. 6  shows a first sectional view of the cutting tool of  FIG. 5 .  
         [0014]      FIG. 7  shows a second sectional view of the cutting tool of  FIG. 5 .  
         [0015]      FIG. 8  shows a cross-sectional view of an alternate embodiment of the cutting tool of  FIG. 1  in which dual tubing is used.  
         [0016]      FIG. 9  shows a sectional view of the cutting tool of  FIG. 8 .  
         [0017]      FIG. 10  shows a cross-sectional view of an alternate embodiment of the cutting tool of  FIG. 1 . 
     
    
     DETAILED DESCRIPTION  
       [0018]     Referring to  FIG. 1 , a cutting tool  10  comprises four primary components: a mandrel  12 , a cutting sleeve  14 , a housing  16 , and lugs  18 .  FIG. 1  also shows a single control line  19 , though the invention is not limited to just one control line. Other figures (e.g.,  FIGS. 3 and 4 ) show, for example, five control lines  19 . Control line  19  may be, for example, a hydraulic conduit, an electric cable, a fiber optic cable, or a combination of those, as well as other devices manifested as a relatively small diameter longitudinal line. A seal  21  is mounted near the lower end of mandrel  12  and serves to prevent the upward invasion of dust and debris.  
         [0019]     In  FIG. 1 , housing  16  is shown retracted from its operational configuration to expose the underlying components. Housing  16  normally encloses mandrel  12  and sleeve  14 . Mandrel  12  provides a tubing cutting target  20  and carries a cutting base  22  near its lower end below target  20 . Base  22  can be integral to mandrel  12  or can be made as a separate component and attached to mandrel  12 . Mandrel  12  mounts at its upper end to an upper end of housing  16 , and at its lower end to a lower portion of a tubing  24 . Housing  16  attaches at its upper end to an upper portion of tubing  24 . Tubing  24 , housing  16 , and mandrel  12 , when so assembled, form a continuous passageway for fluid flow.  
         [0020]     Sleeve  14  is carried on the lower end of mandrel  12  and can move in both rotation and translation relative to mandrel  12  and base  22 . The relative motion provides a cutting action. Base  22  and sleeve  14  have mating helical surfaces  28  and each has a longitudinal passageway through its respective sidewall to accommodate control line  19 . Those passageways are initially aligned. Axial holes  31  in mandrel  12  and axial holes  33  in base  22  of  FIG. 1  show the passageway openings accommodating control line  19 .  
         [0021]     Lugs  18  are carried in slots  26  of sleeve  14  and placed in sliding engagement with the lower end of mandrel  12 . Lugs  18  extend into a groove  29  in the inner surface of housing  16 , linking sleeve  14  to housing  16  while permitting sleeve  14  to rotate relative to housing  16 . A recess  35  in mandrel  12  allows lugs  18  to disengage from housing  16  upon sufficient displacement of sleeve  14 .  
         [0022]     In operation, a tubing cutter such as an explosive jet cutter is placed in the vicinity of tubing cutting target  20 . The cutter is actuated to sever mandrel  12  somewhere along the length of target  20 . Once mandrel  12  is severed, the upper portion of tubing  24  is pulled upward by the operator. Because housing  16  is attached to the upper portion of tubing  24 , housing  16  is pulled upward as well. Since lugs  18  extend into groove  29  of housing  16 , sleeve  14  is also pulled upward. Thus, housing  16  provides a mechanical link between the upper portion of tubing  24  (that has now been severed from the lower portion of tubing  24 ) and cutting sleeve  14  to generate the relative motion required for cutting control line  19 .  
         [0023]     Helical surfaces  28  between sleeve  14  and cutting base  22  cause sleeve  14  to rotate relative to base  22  when sleeve  14  is pulled upward. The rotational motion advances the cutting edge of sleeve  14  through control line  19 , thereby cutting control line  19 . With sufficient upward travel of cutting sleeve  14 , lugs  18  encounter and retract into recess  35  in mandrel  12  to release housing  16 .  
         [0024]     Once housing  16  is released, the upper portion of tubing  24 , along with housing  16  and the upper portion of (severed) mandrel  12  can all be removed from the well. The newly cut end of the upper portion of control line  19  is enclosed inside housing  16  during retrieval. The severed end of the lower portion of control line  19  left in the well is enclosed inside sleeve  14 . The lower portion of tubing  24  remains in the well and the uppermost end of the severed lower portion of mandrel  12  is clear of control lines  19 . Preferably the severed end of mandrel  12  is beveled to allow for easy overshoot. Additionally, the outside diameter of sleeve  14  is preferably small enough to be swallowed up (Le., enclosed and captured), for example, by a burner mill. This allows for removal of the remaining portion of the completion assembly from the well.  
         [0025]      FIGS. 2-4  show an embodiment of cutting tool  10  in which the elements are eccentrically aligned. The eccentric design accommodates more or larger control lines  19 .  
         [0026]      FIGS. 5-7  show an embodiment of cutting tool  10  in which the elements are concentrically aligned. When requirements permit, a concentric design allows for simpler manufacture.  
         [0027]      FIGS. 8-10  show alternative embodiments of cutting tool  10  in which the roles of cutter sleeve  14  and base  22  are reversed. A thrust bearing  36  is placed above cutter sleeve  14  to better allow sleeve  14  to rotate. Base  22  can be integral to mandrel  12  or can be made as a separate component and attached to mandrel  12 . Base  22  and cutter sleeve  14  remain the two arms of the scissors and their helical profiles induce relative rotation between them. They can be manufactured from the same tube to ensure a conformable mating surface. The roles are reversed because the lower portion (base  22 ) is now fixed to mandrel  12 . The upper portion (sleeve  14 ) is now the component that rotates.  
         [0028]      FIGS. 8 and 9  show an embodiment in which dual tubing strings are used. Primary string  38  and secondary string  40  mount in a fashion similar to that described above to housing  16  and mandrel  12 . If it becomes necessary to cut control lines  19 , tubing strings  38 ,  40  are first cut as before. Gaps in sleeve  14  around string  40  and within housing  16  allow sleeve  14  to rotate, cutting control lines  19 .  
         [0029]      FIG. 10  also shows other features such as housing  16  having a channel  41  along its entire length such that housing  16  effectively forms a “C-ring”. That allows control lines  19  to be laid through channel  41  alongside mandrel  12  without regard to alignment holes  31 . Channel  41  in housing  16  is rotated to align with the channels (instead of holes  33 ) in the base  22  and cutter sleeve  14  and control lines  19  are installed through the channels one line at a time. Housing  16  can then be rotated over control lines  19  to protect them from external hazards in the well. To avoid hoop stresses in housing  16 , square threads  42  and square lugs  18  are preferred. Lugs  18  may also need to be spring loaded to insure proper retraction from housing  16 . Base  22  can be restrained by clutch  43  to limit the motion of base  22  to translation only.  
         [0030]     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. Accordingly, all such modifications are intended to be included within the scope of this invention as defined in the following claims. In the claims, means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents, but also equivalent structures. Thus, although a nail and a screw may not be structural equivalents in that a nail employs a cylindrical surface to secure wooden parts together, whereas a screw employs a helical surface, in the environment of fastening wooden parts, a nail and a screw may be equivalent structures. It is the express intention of the applicant not to invoke 35 U.S.C. §112, paragraph 6 for any limitations of any of the claims herein, except for those in which the claim expressly uses the words “means for” together with an associated function.

Technology Classification (CPC): 4