Rotating Control Line Cutting Sub
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.
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This application is claims priority from U.S. Provisional Patent Application Ser. No. 62/157,255, filed on May 5, 2015, the disclosure of which is incorporated herein by reference in its entirety.
FIELD OF THE INVENTIONThe 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 INVENTIONThere 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
This problem is illustrated with an existing tool whose typical use is illustrated in
Arrow 28 in
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 INVENTIONA 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.
Referring to
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.
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:
Claims
1. An auxiliary line cutting apparatus mounted to a tubular string for subterranean use, comprising:
- at least one line mounted to a mandrel;
- a cutting apparatus selectively in contact with said line to cut said line with relative rotational movement of said cutter relative to said mandrel.
2. The apparatus of claim 1, wherein:
- said cutting apparatus moves axially relative to said mandrel.
3. The apparatus of claim 1, wherein:
- said cutting apparatus further comprises a cutting edge oriented closer to axial alignment with a longitudinal axis of said mandrel than to a plane perpendicular to said longitudinal axis of said mandrel.
4. The apparatus of claim 1, wherein:
- said cutting apparatus is mounted on said mandrel on a bearing to facilitate said relative rotation.
5. The apparatus of claim 1, wherein:
- at least a portion of said mandrel moves axially to induce said cutting apparatus to relatively rotate with respect to said mandrel.
6. The apparatus of claim 5, wherein:
- at least a portion of said mandrel remains stationary to induce said cutting apparatus to relatively rotate with respect to said stationary portion of said mandrel.
7. The apparatus of claim 6, wherein:
- said cutting apparatus connected to said stationary mandrel portion with a pin in a spiral slot connection such that axial movement of the moving portion of said mandrel induces said cutting apparatus to rotate as said pin follows said spiral slot.
8. The apparatus of claim 7, wherein:
- said spiral slot is open ended to allow removal of said cutting apparatus with said movable portion of said mandrel.
9. The apparatus of claim 8, wherein:
- said spiral slot continuing into an axial slot further comprising said open end to allow said movable portion of said mandrel to take said cutting apparatus and a portion of the line above the cut away from the subterranean location.
10. The apparatus of claim 9, wherein:
- said portions of said mandrel separable as said pin exits said open end in said axial slot.
11. The apparatus of claim 10, wherein:
- said portions of said mandrel are created with a transverse cut through a wall of said mandrel.
12. The apparatus of claim 2, wherein:
- said relative rotational movement of said cutting apparatus allows a reduction of axial movement of said cutting apparatus as compared to exclusively axial movement of said cutting apparatus for cutting said line.
13. The apparatus of claim 12, wherein:
- said reduction of axial movement is by a factor of at least 10:1.
14. The apparatus of claim 1, wherein:
- said at least one line comprises a plurality of circumferentially spaced lines sequentially cut as said cutting apparatus rotates relatively to said mandrel.
15. The apparatus of claim 2, wherein:
- said cutting apparatus further comprises a cutting edge oriented closer to axial alignment with a longitudinal axis of said mandrel than to a plane perpendicular to said longitudinal axis of said mandrel.
16. The apparatus of claim 15, wherein:
- at least a portion of said mandrel moves axially to induce said cutting apparatus to relatively rotate with respect to said mandrel.
17. The apparatus of claim 16, wherein:
- at least a portion of said mandrel remains stationary to induce said cutting apparatus to relatively rotate with respect to said stationary portion of said mandrel.
18. The apparatus of claim 17, wherein:
- said cutting apparatus connected to said stationary mandrel portion with a pin in a spiral slot connection such that axial movement of the moving portion of said mandrel induces said cutting apparatus to rotate as said pin follows said spiral slot.
19. The apparatus of claim 18, wherein:
- said spiral slot is open ended to allow removal of said cutting apparatus with said movable portion of said mandrel.
20. The apparatus of claim 19, wherein:
- said relative rotational movement of said cutting apparatus allows a reduction of axial movement of said cutting apparatus as compared to exclusively axial movement of said cutting apparatus for cutting said line.
21. The apparatus of claim 20, wherein:
- said reduction of axial movement is by a factor of at least 10:1.
Type: Application
Filed: Nov 10, 2015
Publication Date: Nov 10, 2016
Applicant: BAKER HUGHES INCORPORATED (Houston, TX)
Inventor: Alasdair R. Tait (Portlethen)
Application Number: 14/937,350