Abstract:
A method for driving a ramped drive assembly longitudinally, to drive a penetrator transversely, to cause the penetrator to penetrate and withdraw from a downhole tubular element. An anchor holds the tubing punch assembly in place in the downhole tubular element. A double piston assembly drives the drive assembly hydraulically in the downhole direction, thereby driving the ramp downhole, to force the penetrator outwardly to penetrate the tubular element. Thereafter, pulling uphole on the work string shears a shear sleeve, separating the housing of the tubing punch assembly from the work string. Further pulling on the work string partially withdraws the ramped drive assembly from the tubing punch assembly, thereby withdrawing the penetrator into the tubing punch assembly.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [1]    1. This application is a divisional application of copending U.S. Ser. No. 124,816, filed Jul. 29, 1998, for “Hydraulic Tubing Punch and Method of Use”.  
     
    
     
       STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
         [2]    2. Not Applicable  
         BACKGROUND OF THE INVENTION  
         [3]    3. 1. Field of the Invention  
           [4]    4. This invention is in the field of methods and apparatus used to punch holes through, or place fittings or markers in, downhole tubular elements, such as casing pipe.  
           [5]    5. 2. Background Information  
           [6]    6. In the completion of oil wells, and the production of oil from such wells, it can often become necessary or beneficial to punch one or more holes through, or perforate, the casing which lines the well bore, or the production tubing within the casing. These perforations can have several purposes, such as the creation of a gas lift flow path, the production of different zones or different formations from the well bore, the creation of a circulation path to kill the well, the loosening of sand or mud between the production tubing and the casing, or the placement of an orifice, check valve, or marker in the production tubing or casing. Further, such perforations can be used to create a circulation path to squeeze cement around a leaking packer element or perforation, or to create a circulation path for use in other remedial work, such as stimulation. A tool used for this purpose will ideally be able to be positioned within a highly deviated or even horizontal well bore, it will reliably and safely generate sufficient power to puncture thick walled tubing or casing, it will give the operator a positive indication of complete penetration of the tubing or casing, and it will reliably withdraw completely from the tubing or casing without hanging up.  
           [7]    7. Some tools are available for puncturing tubing, using either a burn-through technique, or a mechanical punch driven by a jarring tool, for creation of the penetration. These tools are typically carried by a wireline. None of the known tools exhibit the ideal attributes listed above. Wireline tools can not be positioned reliably in highly deviated holes. Bum-through tools and jar driven punches do not give reliable indications of complete and uniform penetration, and they are sometimes subject to hanging in the perforation, making withdrawal difficult or impossible.  
         BRIEF SUMMARY OF THE INVENTION  
         [8]    8. The present invention is a method for operating a hydraulically driven punch which generates sufficient, smoothly applied, power to penetrate thick walled tubing and casing. Conveyed on a tubular work string, the punch can be positively positioned at any desired location in a deviated or horizontal well bore before activation. Full penetration is positively signalled to the operator. Withdrawal is positive, and full withdrawal is achieve prior to lifting of the tool, virtually preventing hangup.  
           [9]    9. In the preferred embodiment, a drive assembly, consisting of two stacked pistons and a plunger, moves longitudinally to drive a penetrator element transversely into the production tubing or casing. The housing of the hydraulic tubing punch of the present invention consists of a piston housing and a plunger housing, connected by a releasable sub. The piston housing contains the two stacked hydraulic pistons. The upper piston applies force to the center of the lower piston by means of an upper piston rod. The lower piston is connected by a lower piston rod to the plunger, which is located in the plunger housing. The plunger incorporates a pair of oppositely facing ramped surfaces, angled slightly relative to the longitudinal axis of the tool. The ramped surfaces on the plunger mate with similarly angled surfaces on a penetrator element which can move transversely relative to the longitudinal axis of the tool. In the preferred embodiment, the oppositely facing ramped surfaces on the plunger comprise at least one groove, and the mating surfaces on the penetrator element comprise at least one ridge. The penetrator element incorporates an outwardly oriented punch of hard, durable material, capable of penetrating the production tubing or casing.  
           [10]    10. Application of high pressure drilling fluid or other hydraulic pressure to the upper surface of the upper piston drives it downwardly to cause its piston rod to exert downward force on the lower piston. Throughout this specification, the term “downward” will be used to mean “downhole”, and “upward” will mean “uphole”, even though in some applications the tool will be located in a highly deviated or horizontal well bore. Simultaneous application of hydraulic pressure to the upper surface of the lower piston also forces it downwardly. Downward travel of the lower piston is accompanied by downward travel of the plunger. As the ramped surfaces on the plunger move longitudinally downwardly, they cause the penetrator element to move transversely outwardly, which causes the punch portion of the penetrator element to exit through a window in the plunger housing and punch through the wall of a production tube or a casing surrounding the hydraulic tubing punch tool. A support dog, radially opposite the punch portion of the penetrator element, is forced radially outwardly, simultaneously with, or just prior to, the transverse travel of the penetrator element. The support dog bears against the opposite side of the production tubing or casing to maintain the tubing punch tool axially aligned with the tubing or casing. Additional support dogs can be used to further stabilize the axial alignment of the tool.  
           [11]    11. A bleed port is positioned in the piston housing, at a location just above the full travel position of the upper piston. As the upper piston reaches its full travel position, the bleed port is uncovered, allowing the hydraulic fluid to exit from the interior of the tubing punch to the annulus surrounding the tool. This reduces the hydraulic pressure applied to the pistons, and the pressure drop is seen by the operator at the surface of the well site, signalling full travel of the upper piston. Because of the rigid connection between the pistons and the plunger, full travel of the upper piston is accompanied by substantially full transverse travel of the penetrator element, thereby ensuring full penetration of the production tubing or casing.  
           [12]    12. The work string is then pulled upwardly, with the first upward movement of the work string causing the piston housing to separate from the plunger housing at the releasable sub. Release can be accomplished by shearing a shear pin in the releasable sub upon pulling up on the work string, or by releasing a release dog in the releasable sub upon full downward travel of the lower piston. In either case, pulling of the work string continues upwardly, pulling the piston housing, the pistons, and the plunger upwardly. This upward pulling of the plunger causes the ramped surfaces to pull the penetrator element transversely inward, withdrawing the punch from the tubing or casing. If desired, a fitting, such as an orifice, check valve, or marker tag, can be releasably mounted on the punch, to be left in the tubing or casing upon withdrawal of the punch into the plunger housing. After full retraction of the punch from the tubing or casing, a support profile on the plunger contacts a mating profile on the plunger housing, to enable withdrawal of the plunger housing from the well bore, along with the rest of the tool.  
           [13]    13. An anchor mechanism can be provided to anchor the tubing punch tool within the well bore at any selected location. The anchor mechanism can be hydraulically set, and mechanically released by upward pulling on the work string.  
           [14]    14. The novel features of this invention, as well as the invention itself, will be best understood from the attached drawings, taken along with the following description, in which similar reference characters refer to similar parts, and in which:  
       
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS  
       [15]    15.FIG. 1 is a longitudinal section view of the piston housing of a first embodiment of the hydraulic tubing punch tool of the present invention, before longitudinal travel of the drive assembly;  
         [16]    16.FIG. 2 is a longitudinal section view of the releasable sub and plunger housing of the tool shown in FIG. 1, using a shearable release sub;  
         [17]    17.FIG. 3 is a transverse section view of the penetrator element and support dog of the tool shown in FIG. 2, before extension of the punch;  
         [18]    18.FIG. 4 is a transverse section view of the penetrator element and support dog of the tool shown in FIG. 2, after extension of the punch;  
         [19]    19.FIG. 5 is a transverse section view of the penetrator element and support dog of the tool shown in FIG. 2, showing optional side support dogs;  
         [20]    20.FIG. 6 is a longitudinal section view of the piston housing of the hydraulic tubing punch tool shown in FIG. 1, after full longitudinal travel of the drive assembly;  
         [21]    21.FIG. 7 is a longitudinal section view of the releasable sub and plunger housing of the tool shown in FIG. 6, showing full extension of the penetrator element;  
         [22]    22.FIG. 8 is a longitudinal section view of the lower end of the plunger housing of the tool shown in FIG. 6, showing full downward extension of the plunger;  
         [23]    23.FIG. 9 is a longitudinal section view of the piston housing of a second embodiment of the hydraulic tubing punch tool of the present invention, before longitudinal travel of the drive assembly;  
         [24]    24.FIG. 10 is a longitudinal section view of the releasable sub and plunger housing of the tool shown in FIG. 9, using a release dog in the releasable sub;  
         [25]    25.FIG. 11 is a longitudinal section view of the piston housing of the hydraulic tubing punch tool shown in FIG. 9, after full longitudinal travel of the drive assembly;  
         [26]    26.FIG. 12 is a longitudinal section view of the releasable sub and plunger housing of the tool shown in FIG. 11, showing full extension of the penetrator element; and  
         [27]    27.FIG. 13 is a longitudinal section of a hydraulically settable anchor mechanism for use with the present invention.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [28]    28. As seen in FIG. 1, a first embodiment of the hydraulic tubing punch tool  10  of the present invention includes a piston housing  12 , which preferably consists of an upper piston housing  14  threaded to a lower piston housing  16 . An upper connector sub  18  is threaded to the upper end of the upper piston housing  14 , for connecting the hydraulic tubing punch tool  10  to a work string, such as a drill pipe or coiled tubing (not shown). An upper piston  20  is slidably mounted within the upper piston housing  14  for longitudinal movement. A lower piston  22  is slidably mounted within the lower piston housing  16  for longitudinal movement. A rigid, hollow, upper piston rod  24  extends downwardly from the upper piston  20  to contact the central portion of the upper surface of the lower piston  22 . The abutment between the upper piston rod  24  and the upper central surface of the lower piston  22  can be by means of a loose fit into a cavity within the lower piston  22 , as shown. The inner bore of a work string connected to the upper end of the tool  10  is in fluid flow communication with the upper surface of the upper piston  20 . Simultaneously, the inner bore of the work string is in fluid flow communication with the upper surface of the lower piston  22  via the inner bore of the upper piston rod  24  and via one or more side ports  25  in the upper piston rod  24 .  
         [29]    29. A rigid lower piston rod  26  extends downwardly from the lower piston  22 , with the lower piston rod  26  being pinned to the lower piston housing  16  by one or more shear pins  28 . A plurality of seals  30  provide a fluid seal between the upper piston  20  and the upper piston housing  14 , between the upper piston rod  24  and the upper piston housing  14 , and between the lower piston  22  and the lower piston housing  16 . One or more bleed ports  32  are provided in the wall of the upper piston housing  14 , connecting the interior of the upper piston housing  14  with the annulus surrounding the upper piston housing  14 . The longitudinal placement of the bleed ports  32  is just above the longitudinal position where the upper piston  20  will reach substantially full travel in the downward direction.  
         [30]    30.FIG. 2 shows a releasable sub  34  releasably attached to the lower end of the lower piston housing  16 , and a plunger housing  36  attached to the lower end of the releasable sub  34 . One or more shear pins  38  releasably attach the releasable sub  34  to the lower piston housing  16 . The plunger housing  36  is shown positioned at a selected longitudinal position within a production tubing or casing C. A plunger  40  is fixedly attached to the lower end of the lower piston rod  26 , for instance by means of threads as shown. As seen in FIGS. 2 and 3, a double faced ramp contour, in the form of at least one angled groove  42 , is seen on the interior wall of a longitudinal channel  43  formed in the plunger  40 . Each angled groove  42  includes an outwardly facing angled surface  44  and an inwardly facing angled surface  46 . Further, the ramp contour includes the outwardly facing angled surface  47  at the bottom of the longitudinal channel  43 .  
         [31]    31. A penetrator element  48  is slidably mounted for transverse movement in the lower end of the plunger housing  36 . The penetrator element  48  can consist of a sliding block  49  within which is affixed a hard, durable punch  50 . Various means known in the art can be used to affix the punch  50  to the sliding block  49 , including the use of a retainer plate  51 , which can be bolted to the sliding block  49 . The punch  50  can be fitted with any of several different types of fittings  52 , if desired, such as a marker tag, an orifice, or a check valve. This allows the fitting  52  to be left in the tubing or casing C after penetration by the punch  50 . Alternatively, the punch  50  can be used simply to create a hole in the tubing or casing C.  
         [32]    32. A support dog  54  is mounted for transverse movement within the lower end of the plunger housing  36 , substantially radially opposite the penetrator element  48 . The penetrator element  48  slides in and out of a penetrator window  56  in the lower end of the plunger housing  36 , and the support dog  54  slides in and out of a support dog window  58  in the lower end of the plunger housing  36 . As best seen in FIG. 3, one or more ridges  60  are formed on the lateral sides of the penetrator element  48 , with the ridges being formed at substantially the same angle as the grooves  42  in the plunger  40 . The ridges  60  fit into and mate with the grooves  42 . Further, the angled inside edge  53  of the penetrator element  48  abuts the angled surface  47  at the bottom of the longitudinal channel  43  in the plunger  40 .  
         [33]    33. When the plunger  40  is at the upward limit of its travel as shown in FIGS. 2 and 3, the support dog  54  can rest entirely within the plunger housing  36 , abutting an undercut surface  62  in the lower end of the plunger  40 . In this position, the ridges  60  on the penetrator element  48  follow the grooves  42  on the plunger  40  to cause the penetrator element  48  to be at the inward limit of its transverse travel, fully withdrawn within the plunger housing  36 . It can be seen in FIG. 4 that downward movement of the plunger  40  will cause the full diameter surface  64  of the plunger  40  to force the support dog  54  outward through the support dog window  58  to abut the casing C. Further, in this downward position of the plunger  40 , the ridges  60  on the penetrator element  48  slide in the grooves  42  in the plunger  40  to cause the penetrator element  48  to move transversely outwardly to exit the plunger housing  36  through the penetrator window  56  and penetrate the casing C. As seen in FIG. 5, one or more additional support dogs  66  can be mounted peripherally around the plunger housing  36  to further stabilize the axial alignment of the hydraulic tubing punch tool  10  with the casing C.  
         [34]    34.FIG. 6 shows the upper and lower pistons  20 ,  22  substantially at the lower limit of their longitudinal travel within the upper and lower piston housings  14 ,  16 . When hydraulic pressure is increased to a predetermined value, the shear pins  28  shear, releasing the upper and lower pistons to move downwardly. The pressure level at which the shear pins  28  will shear can be designed to provide an initial impulse to the drive assembly, to facilitate penetration of the tubing or casing C. Upon substantially full downward travel of the upper piston  20 , the bleed ports  32  are uncovered, allowing hydraulic pressure to bleed off from the interior of the upper piston housing  14  to the annulus surrounding the tool  10 . This signals the operator that the upper piston  20  has reached substantially full longitudinal travel, and that, consequentially, the penetrator element  48  has reached substantially full transverse travel. Downward travel of the pistons  20 ,  22  can be stopped by abutment against seats  21 ,  23  in the piston housing  12 . Alternatively, the size and number of the bleed ports  32  can also be designed to bleed off sufficient pressure to essentially stop the downward travel of the pistons  20 ,  22 . The relative length of the upper piston rod  24  can be designed to allow the lower piston  22  to have some additional downward travel after the bleed ports  32  are uncovered by the downward travel of the upper piston  20 .  
         [35]    35.FIG. 7 shows the plunger  40  substantially at the downward limit of its longitudinal travel, with the support dog  54  abutting the casing C for axial alignment, and with the penetrator element  48  having fully penetrated the casing C. FIG. 8 illustrates the extension of the lower end of the plunger  40  from the lower end of the plunger housing  36 .  
         [36]    36. After the penetrator element  48  has fully penetrated the casing C, the operator can pull upwardly on the work string to shear the shear pins  38 , thereby releasing the piston housing  12  from the releasable sub  34  and the plunger housing  36 . During this shearing process, the upward pulling of the work string is resisted by the punch  50  of the penetrator element  48 , which is extended into the casing C. After shearing of the shear pins  38  to release the releasable sub  34 , the piston housing  12  moves upwardly, and the seat  23  abuts the lower piston  22  and pulls the pistons  20 ,  22 , and the plunger  40  upwardly. As the plunger  40  is withdrawn longitudinally into the plunger housing  36 , it can be seen that the plunger  40  will return to the position shown in FIG. 2, within the plunger housing  36 . This withdraws the penetrator element  48  transversely into the plunger housing  36 . When the punch  50  has withdrawn from the casing C, the upper end  68  of the plunger  40  can abut the lower end  69  of the releasable sub  34 , to support the plunger housing  36  from the work string. The entire hydraulic tubing punch tool  10  can then be withdrawn from the well bore.  
         [37]    37.FIGS. 9 through 12 show a second embodiment of the hydraulic tubing punch tool  100 , which utilizes a release dog  138 , rather than the shear pins  38  used in the first embodiment, to release the piston housing  112  from the plunger housing  136 . As seen in FIG. 9, the piston housing  112  consists of an upper piston housing  114  threaded to a lower piston housing  116 . An upper connector sub  118  is threaded to the upper end of the upper piston housing  114 , for connecting the hydraulic tubing punch tool  110  to a work string, such as a drill pipe or coiled tubing (not shown). An upper piston  120  is slidably mounted within the upper piston housing  114  for longitudinal movement. A lower piston  122  is slidably mounted within the lower piston housing  116  for longitudinal movement. A rigid, hollow, upper piston rod  124  extends downwardly from the upper piston  120  to contact the central portion of the upper surface of the lower piston  122 .  
         [38]    38. A rigid lower piston rod  126 , having an undercut portion  127  and a full diameter portion  129 , extends downwardly from the lower piston  122 . A plurality of seals  130  provide a fluid seal between the upper piston  120  and the upper piston housing  114 , between the upper piston rod  124  and the upper piston housing  114 , and between the lower piston  122  and the lower piston housing  116 . One or more bleed ports  132  are provided in the wall of the upper piston housing  114 , connecting the interior of the upper piston housing  114  with the annulus surrounding the upper piston housing  114 .  
         [39]    39.FIG. 10 shows a releasable sub  134  releasably attached to the lower end of the lower piston housing  116 , and a plunger housing  136  attached to the lower end of the releasable sub  134 . The lower piston rod  126  is pinned to the releasable sub  134  by one or more shear pins  128 . One or more release dogs  138  releasably attach the releasable sub  34  to the lower piston housing  16 . The release dogs  138  are held in an outward position by abutment with the full diameter portion  129  of the lower piston rod  126 , when the lower piston  122  is near the upward limit of its travel.  
         [40]    40. A plunger  140  is fixedly attached to the lower end of the lower piston rod  126 . A double faced ramp contour, in the form of at least one angled groove  142 , is seen on the interior wall of a longitudinal channel  143  formed in the plunger  140 .  
         [41]    41. A penetrator element  148  is slidably mounted for transverse movement in the lower end of the plunger housing  136 . The penetrator element  148  includes a hard, durable punch  150 . A support dog  154  is mounted for transverse movement within the lower end of the plunger housing  136 , substantially radially opposite the penetrator element  148 . Similarly to the first embodiment, one or more ridges are formed on the lateral sides of the penetrator element  148 , with the ridges being formed at substantially the same angle as the grooves  142  in the plunger  140 .  
         [42]    42.FIG. 11 shows the upper and lower pistons  120 ,  122  substantially at the lower limit of their longitudinal travel within the upper and lower piston housings  114 ,  116 . When hydraulic pressure is increased to a predetermined value, the shear pins  128  shear, releasing the upper and lower pistons to move downwardly. Upon substantially full downward travel of the upper piston  120 , the bleed ports  132  are uncovered, allowing hydraulic pressure to bleed off from the interior of the upper piston housing  114  to the annulus surrounding the tool  110 .  
         [43]    43.FIG. 12 shows the plunger  140  substantially at the downward limit of its longitudinal travel, with the support dog  154  abutting the casing C for axial alignment, and with the penetrator element  148  having fully penetrated the casing C. The lower piston  122  has moved downward sufficiently to allow the release dogs  138  to fall into the undercut portion  127  of the lower piston rod  126 , thereby withdrawing the outermost portion of the release dog  138  from the recess  170  in the releasable sub  134 , into the hole  172  in the lower piston housing  116 . This releases the releasable sub  134  from the piston housing  112 .  
         [44]    44. After the penetrator element  148  has fully penetrated the casing C, the operator can pull upwardly on the work string to pull the piston housing  112  upwardly. This pulls the pistons  120 ,  122 , and the plunger  140  upwardly. As the plunger  140  is withdrawn longitudinally into the plunger housing  136 , it can be seen that the plunger  140  will return to the position shown in FIG. 10, within the plunger housing  136 . This withdraws the penetrator element  148  transversely into the plunger housing  136 . When the punch  150  has withdrawn from the casing C, the upper end  168  of the plunger  140  can abut the lower end  169  of the releasable sub  134 , to support the plunger housing  136  from the work string. The entire hydraulic tubing punch tool  110  can then be withdrawn from the well bore.  
         [45]    45. In order to assist in the actuation of the hydraulic tubing punch tool  10 ,  110  at any desired location in the casing C, an anchor mechanism can be used in conjunction with the tool. An example of such an anchor mechanism  200  is shown in FIG. 13. An upper connector sub  210  can be threadedly attached to the work string, and the hydraulic tubing punch tool  10 ,  110  can be threadedly attached to the lower connector sub  214 . A hollow mandrel  212  is supported by the upper connector sub  210 , with a drive cone  216  formed on or attached to the outer surface of the mandrel  212 . A split finger collet  218  is slidably mounted on the outer surface of the mandrel  212 , below the drive cone  216 . A port  222  through the wall of the mandrel  212  provides fluid pressure from the work string to drive the collet  218  upwardly. A plurality of slip fingers  220  on the upper ends of the fingers of the collet  218  are driven outwardly by contact with the drive cone  216 . This forces the slip teeth  224  on the outer surfaces of the slip fingers  220  to forcibly contact the casing C, holding the anchor mechanism  200  and the tubing punch  10 ,  110  in position.  
         [46]    46. The same hydraulic pressure that sets the anchor mechanism  200  can actuate the tubing punch  10 ,  110 . After full travel of the drive assembly and the penetrator element  48 ,  148 , pulling upwardly on the work string will cause the drive cone  216  to withdraw from contact with the slip fingers  220 , releasing the anchor mechanism  220 . Thereafter, continued upward pulling on the work string withdraws the penetrator element  48 ,  148  from the casing C, as described above.  
         [47]    47. While the particular invention as herein shown and disclosed in detail is fully capable of obtaining the objects and providing the advantages hereinbefore stated, it is to be understood that this disclosure is merely illustrative of the presently preferred embodiments of the invention and that no limitations are intended other than as described in the appended claims.