ROTATING CONTROL LINE CUTTING SUB

FIELD OF THE INVENTION

[0001] The field of the invention is devices that cut one or more control lines when the tubular string that supports those lines is cut and removed from a subterranean location.

BACKGROUND OF THE INVENTION

[0002] There are occasions where a tubular string with external control lines for operating tools integral to the string needs to be cut and removed from a borehole. In order to get the string above the cut out of the borehole, the associated control lines need to be cut. Typically, the lower end of the string is supported by a packer so the portion of the string below the cut will remain in the hole. After the string is cut the control lines are typically cut using a cutting tool that surrounds the control lines and picking up the string above the cut to bring the cutting blade to the control lines to shear each of them off. However, to accomplish this the string above the cut has to come up a number of inches and this puts significant tensile stress on the control lines. Since the control lines have splice subs where the connection is essentially a push into a receptacle held with a ferrule (see FIG. 7) there was a significant risk that the control line on one side or the other of a connector could release an end of the control line. If that happens there would then be a loose segment between the cut location for the control line and the pullout location from the connector. This loose segment or segments could then jam the cut portion of the string that is being removed and cause a very expensive milling job to get the components freed up for removal from the borehole.

[0003] This problem is illustrated with an existing tool whose typical use is illustrated in FIGS. 1-7. Referring to FIG. la and lb body 10 is connected on opposed ends as part of a tubular string to be cut. A milled sleeve 12 has slots 14 for control lines 16. A splice sub assembly 18 is essentially a connector for opposed ends 15 and 17 of a given control line 16 as shown in FIG. 7. The cut sub 20 has a cutting edge 22 that is moved up to a location of enlarged outer dimension 24 where each of the control lines 16 come out of a respective channel 26 so that edge 22 shears off each line 16 upon relative movement with respect to the portion of the body 10 that remains in the hole, usually supported by a packer that is not shown.

[0004] Arrow 28 in FIG. 2 shows the axial distance the body 10 above the cut has to be lifted to get the edge 22 to the enlarged outer dimension 24 to make the cut. FIG. 3 shows the onset of movement to make the cut with such movement putting a tensile force on the control lines, which can have the effect of pulling one or more control lines 16 out of a respective assembly 18. Arrow 30 indicates the direction of movement of the cut sub 20 with respect to segment 32 that remains stationary supported by a packer that is not shown. FIG. 4 shows further movement to the location of the actual cut.

[0005] FIG. 5 shows the separation from segment 32 of the cut sub 20 as movement continues in the direction of arrow 30. It also shows the control lines 16 pulled out of the splice sub 18 so that multiple segments 36 are formed with their top end 34 and their lower end at the cut location 38. As shown in FIG. 6 these segments 36 are loose and can fall down the hole making subsequent operations such as latching onto segment 32 impossible. If this occurs a very expensive milling operation would be in order.

[0006] The present invention addresses this issue by limiting the tensile stress on the control lines from a cutting mechanism that operates with rotary motion induced from axial movement so that a very limited axial stretching occurs as the lines are cut with a rotatably mounted cutter that is induced to turn as the cut segment of the tubular is axially raised. The axial tensile force is severely limited compared to the all axial design with the result that the applied axial force to the control lines to sever them does not pull out ends of a control line from a connector. These and other aspects of the present invention will be more readily understood by those skilled in the art from a review of the detailed description of the preferred embodiment and the associated drawings while appreciating that the full scope of the invention is to be determined by the appended claims.

SUMMARY OF THE INVENTION

[0007] A control line cutting tool is mounted for rotation in response to lifting the cut segment. The blade is oriented to cut as the cutter is forced to rotate to follow a spiral groove in the portion of the body below the cut. When the follower pin in the cutter reaches the end of the spiral slot all the control lines have been cut with minimal stress on the control lines to accomplish the cut. The pin then enters a longitudinal slot to allow separation of the body above the cut from the remaining portion in the borehole supported by a packer.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] FIGS, la and lb are perspective views of a prior art design for a control line cutter showing the run in position;

[0009] FIG. 2 is a detailed view of FIGS, la and lb showing the amount of axial stroke required to cut the control lines;

[0010] FIG. 3 is the view of FIG. 2 after the tubular is cut and at the onset of movement of the portion of the tubular above the cut;

[0011] FIG. 4 is the view of FIG. 3 showing sufficient movement to cut the control lines;

[0012] FIG. 5 is the view of FIG. 4 showing some control lines pulled out of connector to form loose segments;

[0013] FIG. 6 is the view of FIG. 5 upon further axial movement showing the loose segments before they fall downhole to the remaining part of the cut tubular;

[0014] FIG. 7 is a detailed view of a single connector such as those shown in FIG. lb with the control lines secured in it;

[0015] FIGS. 8a and 8b show rotated views of the body of the present invention showing the cut location and the spiral slot;

[0016] FIGS. 9a and 9b show a section view in perspective illustrating the bearing assembly under the cutting sub that allows relative rotation with respect to the body;

[0017] FIGS. 10a and 10b are a section view of the body showing the cut zone and the actual cut, respectively;

[0018] FIG. 11 is a detailed view of the cutting sub;

[0019] FIGS. 12a and 12b illustrate the pin in the cutting sub and the spiral track that causes it to rotate;

[0020] FIG. 13 shows the onset of rotation of the cutting sub;

[0021] FIGS. 14a and 14b are perspective views showing the cut and the onset of rotation of the cutting sub;

[0022] FIG. 15 is a detailed view of the control lines being cut; [0023] FIG. 16 shows an axial portion of the slot after the spiral portion to allow the portion of the body above the cut to separate from the portion below the cut;

[0024] FIGS. 17a and 17b show component separation with the cut control lines remaining in the connectors and in the body portion below the cut to avoid loose control line segments;

[0025] FIG. 18 shows the body components fully separated after the control lines have been cut.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0026] Referring to FIG. 8a the body 40 has a cut zone indicated by arrow 42 and a series of axial grooves 44 into which control lines 46 will extend while coming out of grooves 44 at upper ends 48 as shown in FIG. 9b. A spirally oriented slot 50 ends in an axially oriented slot 52 for inducing rotation of the cutting sub 54 on bearing 56 as will be explained in more detail below.

As with the prior design the body 40 has a milled sleeve 58 with grooves 60 in which connectors 62 connect opposed loose ends to make a continuous control line such as 46 as best shown in FIG. 12a. Milled sleeve 58 supports cutting sub 54 as best shown in FIG. 9b. Spacer sleeve 64 helps to retain the bearing 56 in position under cutting sub 54.

[0027] FIGS. 10a and 10b graphically show the making of the cut 66 in the cutting zone indicated by arrow 42. Once the cut 66 is made the body segment 68 that is above the cut can be picked up. This raises the cutting sub 54 and induces its rotation and with it the rotation of cutting edge 70. Contrary to the orientation of the cutting edge 22 transverse to the direction of tubular motion, the cutting edge 70 in the present invention is more axially oriented than transversely oriented with a slight angle of incline as best seen in FIG. 11. A port 72 accepts a guide pin 74 as best shown in FIG. 12b. The pin 74 initially sits at a starting end 76 of spiral slot 50. Those skilled in the art will appreciate that picking up on segment 68 will induce rotation of cutting sub 54 as the pin 74 follows the spiral path of groove 50 away from end 76 and toward the axially oriented slot 52. At that point the pin 74 can come out of the segment 78 that is below the cut 66 and is held fixed by a packer that is not shown. Since the cutting sub 54 is mounted on a bearing 56 the pin can move in the slot 50 to induce rotation of the cutting sub 54.

[0028] FIG. 13 shows the position of pin 74 from near the end 76 of spiral slot 50 at the onset of picking up segment 68. The cut sub 54 will rise slightly as it rotates on its bearing 56 with pin 74 moving toward axially oriented slot 52. FIGS 14a and 14b show segment 68 moving in the direction of arrow 79 as pin 74 moves in the spiral direction of arrow 80. FIG. 15 shows cut sub 54 raised and rotated in the direction of arrow 80 to bring the cutting edge 70 across the control lines 46 that extend beyond ends 48 of grooves 44. FIG. 16 shows the position of the pin 74 at axial slot 52 so that segments 68 and 78 can come fully apart.

[0029] FIGS. 17a and 17b show the separated segments 68 and 78 with ends 82 of control lines 46 in grooves 44 and coming just short of the ends 48 of grooves 44. In that position the ends 82 are out of the way of later operations. On the other hand, ends 84 move in the direction of arrow 79 and come out of the hole with segment 68 and down to attached cut sub 54. FIG. 18 is a part section perspective of the movement shown ion FIGS. 17a and 17b.

[0030] Those skilled in the art will appreciate that the amount of tension applied to the control lines is greatly diminished because the axial travel has been reduced to get to the cutting position of the prior tool. While there is some axial travel the pitch of the spiral groove is such that the bulk of the motion is rotational for the cut sub 54 rather than axial movement. Depending on the pitch the amount of axial travel to get the cutting done is decreased by a factor of at least 10. The cutting edge is reoriented to accommodate the cutting with rotation rather than a straight axial pull. The control lines are now less likely to be pulled out of connectors which would create a loose segment of control line that could be the cause of a very expensive milling job.

[0031] The above description is illustrative of the preferred embodiment and many modifications may be made by those skilled in the art without departing from the invention whose scope is to be determined from the literal and equivalent scope of the claims below: