US3396795A

US3396795A - Tubing cutter

Info

Publication number: US3396795A
Application number: US578189A
Authority: US
Inventors: Alexis A Venghiattis
Original assignee: Dresser Industries Inc
Current assignee: Dresser Industries Inc
Priority date: 1966-09-09
Filing date: 1966-09-09
Publication date: 1968-08-13
Anticipated expiration: 1985-08-13

Description

Aug. 13, 1968 A. A. VENGHIATTIS TUBING CUTTER 2 Sheets-Sheet 2 Filed Sept. 1966 2 8 6 6 7 9 9 6 3 4 E E R R w u m F F 8 O O 2 7 8 4 I 4 O a a A m/ h//////// r/ //A////// o a w 8 m O O o o o o d o 9 //Vv 4 2 INVENTOR. ALEXIS A. VENGHIATTIS g r a 4m FIGURE 5 ATTORNEY United States Patent 3,396,795 TUBING CUTTER Alexis A. Venghiattis, Weston, Conn., assignor to Dresser Industries, Inc., Dallas, Tex., a corporation of Delaware Filed Sept. 9, 1966, Ser. No. 578,189 Claims. (Cl. 16655.7)

This invention relates generally to improved apparatus for cutting tubing, pipe, or the like from the interior thereof along a plane disposed substantially perpendicularly to the longitudinal axis of the tubing. More particularly, but not by way of limitation, this invention relates to an improved cutter arranged to be run into the tubing on a wire line and to utilize centrifugal force for maintaining the cutters in cutting engagement with the tubing.

In completing an oil or gas well for production, a length of relatively small diameter tubing is disposed in the well bore with the lower end thereof situated adjacent the productive formation. Frequently, the tubing extends through one or more packers that function to isolate various formations Within the well bore.

Occasionally, the tubing must be removed from the well bore. In removing the tubing, it will generally pass through one or more of the packers. Sometimes, the tubing becomes stuck and cannot be removed or, perhaps, only a section thereof is to be removed. In such instances, and if the section to be removed must pass through the packers, it is important that the tubing be cut without expanding or severely burring the outside diameter of the tubing. If such expansion or burring occurs, the tubing will not pass through the packers without damage to or destruction of the packers.

Various devices have been constructed for the purpose of cutting the tubing. A great deal of difficulty has been encountered in the attempt to construct a mechanical tubing cutter due to the relatively small diameter through which the cutter must pass and the small area in which the cutter must operate. Most mechanical cutters have included some form of gear train for driving the cutting blades whereby they will perform the cutting operation. Manifestly, cutters utilizing gear train drives have been ineffective due to their complexity and also due to their inherent weakness when such gear trains are reduced to the size necessary to pass through the tubing. Cutting devices of this type have been efiective for use in the relatively larger diameter casing and similar pipes and conduits.

Explosive cutting devices have also been constructed, but they have not been entirely satisfactory due to their inherent tendency to deform the pipe and thereby increase the outside diameter so that the tubing will not pass through the packers. Various forms of the explosive cutting devices have been constructed, but none have avoided the problem of deformation of the tubing.

Various forms of chemical cutting devices have also been constructed. By and large, the chemical cutters have proved to be the most successful in cutting tubing since they do not expand the tubing diameter.

This invention provides an improved tubing cutter comprising: a motor including a rotatable shaft; holding means responsive to the reaction of the motor for en gaging the tubing to prevent rotation of the motor; a pair of spaced sleeves slidingly disposed on the shaft and rotatable therewith; resilient means biasing the sleeves relatively apart; and, a cutter assembly located between the sleeves and including a plurality of segmented cutter members arranged circumferentially around the shaft, and linkage means interconnecting the cutter members and sleeves, whereby the cutter members are moved relatively outwardly into cutting engagement with the tubing 3,396,795 Patented Aug. 13, 1968 ice by centrifugal force when the shaft is rotating and are biased relatively inwardly out of engagement with the tubing when the rotation ceases.

One object of this invention is to provide an improved mechanical tubing cutter that can be utilized in relatively small diameter tubing.

Another object of this invention is to provide an improved tubing cutter that utilizes centrifugal force for moving the cutters into cutting engagement with the tubmg.

An additional object of the invention is to provide an improved tubing cutter for severing tubing located in a well bore and that is positioned therein by means of a Wire line.

An additional object of the invention is to provide an improved mechanical tubing cutter that can be easily and economically manufactured.

The foregoing and additional objects and advantages of the invention will become more apparent as the following description is read in conjunction with the accompanying drawings wherein like reference characters denote like parts in all views and wherein:

FIGURE 1A is a vertical, cross-sectional view of the upper portion of a tubing cutter constructed in accordance with the invention and disposed in a section of tubmg;

FIGURE 1B is a vertical, cross-sectional view of the lower portion of the cutter disposed in the section of tubing;

FIGURE 2 is a cross-sectional view taken substantially along the line 22 of FIGURE 1A;

FIGURE 3 is a cross-sectional view taken substantially along the line 33 of FIGURE 1B;

FIGURE 4 is a cross-sectional view taken substantially along the line 44 of FIGURE 1B; and,

FIGURE 5 is a vertical, cross-sectional view similar to FIGURE 1B, but illustrating the cutters in cutting engagement with the tubing.

Referring to the drawing and FIGURES 1A and 1B in particular, shown therein and generally designated by the reference character 10 is a tubing cutter constructed in accordance with the invention. The tubing cutter 10 is disposed in the interior of a tubing 12 that is positioned in a well bore (not shown).

As illustrated, the cutter 10 is suspended in the tubing 12 on a wire line or cable 14. The cable 14 is connected by a conventional cable head 16 to a hollow housing member 18 that forms a portion of the tubing cutter 10.

A motor 20 is disposed within the housing member 18 and is electrically connected by means not shown through the wire line 14 with a source of electrical energy (not shown). The motor 20 is pivotally supported in the housing member 18 between an upper motor support 22 and a lower motor support 24.

As illustrated in FIGURE 1A, the upper motor support 22 is restrained against upward movement in the housing member 18 by a conventional internal lock ring 25. A spherical bearing 26 is disposed between the upper motor support 22 and the upper end of the motor 20 to permit pivotal or rotational movement of the motor 20 relative to the upper motor support 22 and housing member 18.

A cam 28, which will be described in more detail hereinafter, is connected with the lower end of the motor 20 by a plurality of threaded fasteners 30. A thrust bearing 32 encircles a portion of the cam 28 and is in engagement with the lower motor support 24, thereby pivotally supporting the lower end of the motor 20 in the housing member 18.

As clearly illustrated in FIGURE 1A, the lower motor support 24 is in threaded engagement with the housing member 18 and is therefore movable longitudinally with respect to the housing member 18 to permit adjustment of the

thrust bearings

26 and 32 supporting the motor 20. A set screw 34 extends through the housing member 18 into engagement with the lower motor support 24 to prevent inadvertent rotation of the motor support 24 after assembly of the motor in the housing member 18.

An output shaft 36, which is rotatably supported in the motor 28, extends through an opening 38 formed in the cam 28. The output shaft 36 is connected with a shaft extension 40 by a threaded fastener 42 that extends through the extension 40 and through the output shaft 36.

The housing member 18 is provided with a pair of threaded openings 44 that extend through the wall thereof in diametrically opposed locations. Each of the openings 44 are provided with a threaded guide bushing 46 having an aperture 48 extending therethrough.

A holding dog or plunger 50 is slidingly disposed in each of the apertures 48. The plungers 50 have a pointedouter end 52 arranged to engage the tubing 12 as illustrated in dash lines in FIGURE 2. A rounded inner end 54 on each of the plungers 50 is disposed in sliding engagement with the surface of the cam 28.

A compression spring 56 encircles a portion of each of the plungers 50 and has one end connected thereto adjacent the inner ends 54. The opposite end of each of the springs 56 is disposed in engagement with a respective one of the guide bushings 46. The springs 56 are of the compression type so that the plungers 50 are constantly biased inwardly, whereby the inner ends 54 thereon remain in engagement with the surface of the cam 28 at all times.

As may be seen more clearly in FIGURE 2, the surface of the cam 28 is substantially elliptical in configuration. The inner ends 54 on the plungers 50 are in engagement with the cam 28 along its minor axis when they are in the retracted position as illustrated by the solid lines in FIGURE 2.

When the motor 20 is energized to rotate the shaft 36, the motor 20 and the attached cam 28 react to the rotation by pivoting on the

bearings

26 and 32 in the opposite direction, that is, into the position illustrated by the dash lines in FIGURE 2. As the cam 28 pivots, the plungers 50 ride along the elliptical surface and, therefore, move outwardly as the major axis of the cam 28 moves toward the plungers 50. When the rotation of the shaft 36 ceases, the springs 56 drive the dogs 50 relatively inwardly, thereby returning the cam 28 and the motor 20 to the position shown in FIGURE 1A wherein the plungers 50 are fully retracted.

Aiding in restoring the cam 28 and the motor 20 to the retracted position are a pair of springs 58. As shown in FIGURE 1A, each of the springs 58 has one end connected with the housing member 18 by a fastener 60 and the other end connected with the motor 20 adjacent the bearing 26 by a fastener 62. As the motor 20 pivots about the

bearings

26 and 32, a force is imposed on the springs 58 which, when the rotation of the shaft 36 ceases, returns or restores the motor 20 to its original position.

As shown in FIGURE 1B, the lower end of the shaft extension 40 is journalled in a thrust bearing 64 located in a centralizer assembly 66. The shaft extension 40 and centralizer assembly 66 are retained in assembled relationship by the engagement of a washer 68 located on the shaft extension 40 with a shoulder 70 formed in the body 72 of the centralizer assembly 66. A nut 74 is in engagement with a threaded portion 76 of the shaft extension 40, thereby retaining the washer 68 on the shaft extension 40.

As is more clearly shown in FIGURES 3 and 4, the shaft extension 40 is substantially square in cross-section. However, the lower end, which is journalled in the thrust bearing 64 and extends into the body 72 of the centralizer assembly 66, is circular in cross-section as required.

As shown in FIGURES 1A and 1B, a pair of identically constructed, though oppositely disposed, sleeves 78 are slidingly located on the square portion of the shaft extension 40. The sleeves 78 are each provided with a square aperture 80 (see also FIGURE 4) that is sized to receive the shaft extension 40. Due to the square configuration of the shaft extension 40 and the apertures 80, it can be appreciated that the sleeves 78 rotate with the shaft extension 40. A collar 82 is mounted on the upper end of the shaft extension 40 (see FIGURE 1A) to limit the upward movement of the uppermost of the sleeves 78.

A compression spring 84 encircles the shaft extension 40 between the sleeves 78. One end of the spring 84 engages the uppermost sleeve 78 and the other end engages the lowermost sleeve 78, whereby the sleeves are biased relatively apart for reasons that will become more apparent hereinafter.

A plurality of hinges 86 are radially spaced about the sleeves 78. One end of each of the hinges 86 is connected with a respective one of the sleeves 78 in any suitable manner. The opposite end of each of the hinges 86 is connected with one end of a respective elongated member 88. As illustrated in FIGURE 1B, and when in the retracted position, the elongated members 88 extend generally parallel to the shaft extension 40. The opposite end of each of the elongated members 88 is connected with a cutter assembly 90.

Each cutter assembly 90 includes a pair of hinge members 92 and a cutter blade 94 mounted between and con nected to the hinge members 92. As illustrated, adjacent ends of the elongated members 88 are connected with the opposite end of each of the hinge members 92, whereby the cutter blades 94 are supported by an articulated linkage consisting of the hinge members 92, the elongated members 88 and the hinges 86 which, as previously described, are mounted on the sleeves 78.

Referring to FIGURE 3, it can be seen that each of the cutter blades 94 has a toothed arcuate outer edge which, when extended, engages the interior of the tubing 12 to perform the cutting operation on the tubing 12. It will be understood that instead of the toothed outer edge form illustrated, the cutter blades 94 may comprise segments of a circular grinder of any suitable material that will function to perform the cutting operation. When the cutter blades 94 are assembled in the six positions illustrated by the elongated members 88 in FIGURE 3, it can be appreciated that a substantially circular cutter is formed.

The centralizer assembly 66, in addition to the body 72, includes a plurality of radially spaced, resilient centralizer members 96 that are sized to slidingly engage the interior of the tubing 12, thereby holding the tubing cutter 10 substantially centered in the tubing 12. The centralizer members 96 are disposed in slots 98 formed in the body 72 and are each connected to the body 72 by a pair of threaded fasteners 100.

Operation When it is desired to sever the tubing 12, the tubing cutter 10 is connected by the cable 14 with a hoisting apparatus (not shown) located on the surface near the top of the well bore (not shown). The tubing cutter 10 is lowered into the tubing 12 with the various components thereof positioned as illustrated in FIGURES 1A and 1B, that is, in the retracted position. When the blades 94 of the cutters 90 have reached a position in the tubing 12 adjacent the location wherein the tubing 12 is to be cut, the hoisting apparatus (not shown) is stopped, thereby suspending the tubing cutter 10 in the tubing 12.

To sever the tubing 12, the motor 20 is energized, whereby the shaft 36 begins to rotate in a clockwise direction as seen in FIGURES 2 and 3 when the cutter blades 94 are constructed as illustrated in FIGURE 3. As a reaction to the rotation of the shaft 36, the motor 20 and cam 28 pivot about the

bearing

26 and 32 in a counter-clockwise direction so that the holding dogs 50, which are riding on the surface of the cam 28, are moved relatively outwardly until the pointed outer ends 52 thereon engage the inner wall of the tubing 12. When this occurs, the reactive pivotation of the motor 20 and cam 28 is arrested. Also, it can be appreciated that the tubing cutter is prevented from rotating relative to the tubing 12 and from moving in a vertical direction relative thereto. Furthermore, the greater the force exerted on the rotating parts of the tubing cutter 10, the greater will be the reactive force exerted to hold the dogs 50 in engagement with the tubing 12.

As the motor shaft 36 rotates, the shaft extension 40, the sleeves 78 and the connected articulated linkage and cutter assemblies 90 also rotate. Centrifugal force resulting from the rotation of the cutter assemblies 90 forces the cutter assemblies 90 relatively outwardly bringing the cutter blades 94 into engagement with the interior wall of the tubing 12. It will be noted that the articulated linkage provided permits the cutter blades 94 to move outwardly in a plane disposed perpendicularly to the longitudinal axis of the tubing 12.

As the cutter assemblies 90 move outwardly, a force is imposed on the sleeves 78 through the elongated members 88 moving the sleeves 78 relatively together. As the sleeves 78 move together, the spring 84 is compressed. Continued rotation of the shaft extension 40 results in the formation of a circumferential slot in the tubing 12 as illustrated in FIGURE 1B and ultimately in the severing of the tubing 12.

After the tubing 12 has been severed, the motor 20 is deenergized resulting in the cessation of rotation of the shaft 36 and the shaft extension 40. As the shaft extension 40 slows down and ceases to rotate, the centrifugal force exerted on the cutter assemblies 90 diminishes until it disappears entirely. When and as this occurs, the spring 84 returns to its unstressed condition forcing the sleeves 78 relatively apart. As the sleeves 78 move relatively apart, the cutter assemblies 90 are retracted and the elongated members 88 return to the retracted position illustrated in FIGURE 1B.

Simultaneously, the motor 20 and the cam 28 are returned to the position illustrated in FIGURE 1A and in solid lines in FIGURE 2 due to the restoring force exerted by the springs 58 on the motor 20 and the restoring force exerted by the springs 56 on the holding dogs 50. Thus, the holding dogs 50 are Withdrawn from engagement with the interior wall of the tubing 12 and the tubing cutter 10 is in condition for withdrawal through the tubing 12.

From the foregoing detailed description, it can be appreciated that the tubing cutter 10 is relatively simple in construction. Due to the elimination of the previously used gear drives for the cutters and due to the elimination of the relatively complex holding mechanisms previously utilized in wire line supported cutters, it can be appreciated that the tubing cutter 10 can be constructed in a very small and compact size and can, therefore, be effectively utilized to sever relatively small diameter tubing.

It will be understood that the single embodiment described in detail hereinbefore is presented by way of example only and that many changes and modifications can be made thereto without departing from the spirit of the invention or from the scope of the annexed claims.

What I claim is:

1. In a tubing cutter:

a motor including a rotatable shaft;

holding means responsive to the reaction of said motor for engaging the tubing to prevent rotation of said motor;

a pair of spaced sleeves slidingly disposed on said shaft and rotatable therewith;

resilient means biasing said sleeves relatively apart;

and,

a cutter assembly located between said sleeves, said cutter assembly including a plurality of segmented cutter members arranged circumferentially around said shaft, and

linkage means interconnecting said cutter members and sleeves, whereby said cutter members are moved relatively outwardly by centrifugal force into cutting engagement with the tubing when said shaft is rotating and are biased relatively inwardly out of engagement with the tubing as said rotation ceases.

2. The tubing cutter of claim 1 wherein said holding means includes:

a hollow housing member pivotally supporting said motor, said housing member being arranged for movement through said tubing and having at least two apertures extending through the wall thereof;

a cam member attached to said motor;

a holding dog slidingly disposed in each said aperture and having one end in engagement with said cam member, whereby reactive pivotation of said motor and cam member biases said dogs relatively outwardly into holding engagement with the tubing.

3. The tubing cutter of claim 1 wherein said linkage means includes a pair of elongated members having one end pivotally connected with each of said cutter members and having the other end of each said elongated member pivotally connected with a respective one of said sleeves.

4. The tubing cutter of claim 1 and also including centralizer means journaling one end of said shaft and arranged to slidingly engage the interior wall of the tubing to center said tubing cutter therein.

5. The tubing cutter of claim 4 wherein said centralizer means includes:

a body member;

bearing means located in said body member and engaging said shaft, whereby said shaft is rotatable relative to said body member;

connecting means holding said shaft, bearing means and body member assembled; and,

a plurality of radially spaced, resilient centralizer members connected with said body member and pro- -jecting outwardly therefrom for engaging the tubing.

6. A cutter for severing tubing located in a well bore, said cutter comprising:

a hollow housing member arranged to be moved through the tubing;

a motor pivotally disposed in said housing member and including a rotatable shaft projecting therefrom;

holding means responsive to the reaction of said motor for engaging the tubing to prevent rotation of said motor; and

a cutter assembly operably mounted on said shaft, said cutter assembly including a plurality of segmented cutter members arranged circumferentially around said shaft, and

linkage means operably connecting said cutter members with said shaft, whereby said cutter members are moved by centrifugal force, when said shaft is rotating, into cutting engagement with the tubing.

7. The cutter of claim 6 wherein said linkage means includes:

a pair of spaced sleeves slidingly disposed on said shaft and rotatable therewith, one of said sleeves being located on each side of said cutter members;

spring means engaging said sleeves for biasing said sleeves relatively apart;

a pair of elongated members having one end of each of said elongated members connected with a respective one of said cutter members and having the other end of each of said elongated members connected with a respective one of said sleeves.

8. The cutter of claim 6 and also including:

means connected with said housing member for moving said cutter through the tubing; and,

centralizer means journaling one end of said shaft and arranged to slidingly engage the interior wall of the tubing to center said cutter therein.

9. A cutter for severing tubing located in a well bore,

said cutter comprising:

a hollow housing member arranged to be moved through the tubing and having at least two apertures exending through the wall thereof;

a motor pivotally disposed in said housing member and having a rotatable shaft projecting from said motor;

a cam member attached to said motor and pivotal therewith;

a holding dog slidingly disposed in each said aperture and having one end in engagement with said cam member, whereby reactive pivotation of said motor and cam member biases said dogs relatively outwardly into holding engagement with the tubing to prevent rotation of said motor relative to said housing member and to prevent movement of said cutter relative to the tubing;

a shaft extension having one end connected with said motor shaft;

a centralizer assembly spaced from said body member and journaling the other end of said shaft extension;

a pair of spaced sleeves slidingly disposed on said shaft extension, said sleeves being rotatable with said shaft extension;

spring means encircling said shaft extension between and in engagement wi'h said sleeves for biasing said sleeves relatively apart; and,

a. cutter assembly located between said sleeves, said cutter assembly including a plurality of segmented cutter members arranged circumferentially around said shaft extension, and

flexible linkage means interconnecting said cutter members and sleeves, whereby said cutter members are moved relatively outwardly by centrifugal force into cutting engagement with the tubing when said shaft extension is rotating and are biased relatively inwardly out of engagement with the tubing by said spring means when said rotation ceases. 10. The cutter of claim 9 and also including: means connected with said housing member for moving said cutter through the tubing; and wherein said centralizer assembly includes a body member, bearing means located in said body member and engaging said shaft extension, whereby said shaft extension is rotatable relative to said body member, connecting means holding said shaft extension, bearing means and body member assembled, and a plurality of radially spaced, resilient centralizer members connected with said body member and projecting outwardly therefrom for slidingly engaging the tubing to center said cutter therein.

References Cited UNITED STATES PATENTS 1,358,818 11/1920 Bering 16655.7 1,498,463 6/1924 McCloskey et a1. 175-285 2,280,769 4/1942 Page 16655.7 X 2,638,801 5/1953 Klaasen et a1. 16655.7 X

DAVID H. BROWN, Primary Examiner.

Claims

6. A CUTTER FOR SEVERING TUBING LOCATED IN A WELL BORE, SAID CUTTER COMPRISING: A HOLLOW HOUSING MEMBER ARRANGED TO BE MOVED THROUGH THE TUBING; A MOTOR PIVOTALLY DISPOSED IN SAID HOUSING MEMBER AND INCLUDING A ROTATABLE SHAFT PROJECTING THEREFROM; HOLDING MEANS RESPONSIVE TO THE REACTION OF SAID MOTOR FOR ENGAGING THE TUBING TO PREVENT ROTATION OF SAID MOTOR; AND A CUTTER ASSEMBLY OPERABLY MOUNTED ON SAID SHAFT, SAID CUTTER ASSEMBLY INCLUDING A PLURALITY OF SEGMENTED CUTTER MEMBERS ARRANGED CIRCUMFERENTIALLY AROUND SAID SHAFT, AND