BIT BREAKER
A bit breaker for loosening or tightening a drill bit on a drill string incorporating a mud motor permits rotation of the drill bit while the bit box is held stationary. The bit breaker has a lower body which is held stationary on the rig floor and an upper body which houses the drill bit and which is connected to the lower body through a rotational connection. An actuator connected between the upper and lower bodies causes the upper body to rotate relative to lower body for co-rotating the drill bit. The bit box of the mud motor is held stationary using the lower tong of a conventional make-and-break unit.
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Embodiments of the invention are related to apparatus used during threaded connection and disconnection of drill bits to a tubular drill string and, more particularly, for use where a mud motor is incorporated into the drill string.
BACKGROUND OF THE INVENTIONIn the oil and gas industry, drill bits are connected to a downhole end of a string of tubulars for drilling a wellbore. The drill bit is threaded to a bottom of the downhole-most drill string tubular or to a bottomhole assembly connected thereto.
Conventional wrenches or tongs cannot be used directly to tighten or loosen bits from the drill string tubular or bottomhole assembly. It is known to provide a shaped box called a bit breaker. The bit breaker is fit to the rig floor, such as to the rotary table. The bit breaker is configurable to the bit shape so as to engage and control bit rotation without damage to the bit. The bit breaker holds the bit stationary while the drill string is rotated for tightening or loosening the bit thereto.
In other implementations, mud motors are incorporated into drill string tubulars or a bottomhole assembly to drive and steer the drill bit. While mud motors are known to be used to enhance rate of penetration (ROP) when drilling vertical wellbores, they are more typically incorporated into bottomhole assemblies for directional drilling of deviated wellbores. Mud motors use mud flow to generate bit rotational speed and torque. Mud is pumped down the drill string to a power section of the mud motor. The power section consists of a lobed steel rotor inside a lobed stator made from a special resilient compound. The rotor, which is usually chromed or polished, has one less lobe than the stator so the mud forces the rotor to rotate within the stator. The rotation of the rotor is transmitted to a drive shaft and transmission section which drives a rotatable bit box on the motor's distal end to hold the drill bit.
In the case where a mud motor is used, the bit box of the mud motor rotates independent from the drill string. Thus, make-up and break-out of a drill string incorporating the mud motor, using a conventional bit breaker with rotation of the drill string, will not result in rotation of the mud motor's bit box and therefore will not act to tighten or loosen the bit thereto.
The oil and gas industry has made a great effort to eliminate the use of manual power tongs wherever possible as they are very dangerous to rig personnel. Further, the process using manual tongs becomes very time consuming to make-up and break-out drill string connections and valuable drilling time is lost.
In order to increase safety and efficiency, hydraulic make-and-break units which comprise power tongs or wrenches are now used to replace manual methods of making-up and breaking out drill strings. Typically, such units comprise rotatable upper tongs for rotating a new stand of drill pipe and stationary lower tongs for holding the string stationary. In the case where a mud motor is used, when the drill bit is positioned and held stationary in the bit breaker, the rotatable bit box is generally adjacent the lower stationary tongs. The power wrench cannot be lowered sufficiently on the rig floor to permit the upper rotatable tongs to engage the bit box of the mud motor for rotation relative to the stationary bit. Accordingly, Applicant notes that, despite the risks to personnel and the mud motor itself, the industry continues to use a manual rotary tong to rotate the bit box while a conventional bit breaker holds the bit stationary.
In addition to the undesirable use of a manual rotary tong, rotation of the bit box may result in damage to the mud motor. When engaging the bit box one must be sure to avoid contacting the end cap directly above the bit box with the tong dies. Further, it has been recommended that the bit box not be held stationary while rotating the mud motor counter-clockwise, or that the mud motor be held stationary while the bit box is rotated clockwise. Such actions may cause the internal mud motor connections to back off resulting in damage to the mud motor. Although rotating in the opposite counterclockwise direction will result in drilling fluid being pushed out the top end, the internal connections will not be at risk of disconnecting or getting wet and causing damage to the motor.
There is a need for apparatus which permits safe and relatively rapid connection and disconnection of a drill bit from a drill string when the drill string incorporates a mud motor and which does not cause costly damage to the mud motor.
SUMMARY OF THE INVENTIONIn embodiments disclosed herein, a conventional hydraulic make-and-break unit can now be employed to make and break a drill bit from the bit box of a mud motor. A bit breaker includes that which permits a drill bit to be bi-directionally and rotationally indexed for loosening and tightening a threaded connection to the mud motor's bit box. The bit box 6 can be held stationary, such as by using lower stationary tongs of the conventional hydraulic make-and-break unit. In one embodiment, the bit breaker 10 has an upper rotatable body for rotating the drill bit relative to a lower stationary body and about an axis common with the bit box. The upper body can be rotationally guided by an arcuate track between the upper and lower bodies. A double-acting hydraulic actuator, between the upper and lower bodies, can provide the bidirectional rotation of the upper body and drill bit. Use of an actuator such as a hydraulic ram provides for a modest rotational range sufficient for making and breaking the threaded connection.
In one broad aspect, a bit breaker for use in threading a drill bit to or from a mud motor having a lower, normally rotatable bit box, the bit breaker comprising: a rotatable bit breaker body for housing the drill bit for co-rotation therewith; and an actuator connected between the bit breaker body and a stationary member, wherein, when the mud motor's bit box is held stationary, the actuator is actuable to co-rotate the bit breaker body and drill bit housed therein relative to the stationary member about an axis common to the drill bit, the bit breaker and the mud motor, the body being rotated in a first direction for loosening a threaded connection between the drill bit and the mud motor's bit box; and in a second direction for tightening the threaded connection between the drill bit and the mud motor's bit box.
In another broad aspect, a system for applying torque to a drill bit on a mud motor with a lower, normally rotatable bit box, the system comprising: a bit breaker having a rotatable bit breaker body for housing the drill bit for co-rotation therewith; and an actuator connected between the bit breaker body and a stationary member, the actuator causing the body to rotate relative to the stationary member; and a tong for holding the bit box stationary, wherein, when the tong is actuated to hold the mud motor's bit box stationary, the actuator is actuable to co-rotate the bit breaker body and drill bit housed therein relative to the stationary member about a common axis, the body being rotated in a first direction for loosening a threaded connection between the drill bit and the mud motor's bit box; and in a second direction for tightening the threaded connection between the drill bit and the mud motor's bit box.
In a broad method aspect, a method for applying torque to a drill bit on a mud motor with a lower, normally rotatable bit box for loosening or tightening a threaded connection between the drill bit and the bit box, comprises: providing a bit breaker having a rotatable bit breaker body having an enclosure for housing the drill bit therein for co-rotation therewith; and an actuator connected between the bit breaker body and a stationary member, the actuator being actuable to cause the body to rotate relative to the stationary member about an axis common to the drill bit and the bit box; inserting the drill bit threaded to the bit box into the enclosure of the bit breaker body; engaging the bit box for holding the bit box stationary; actuating the actuator to co-rotate the bit breaker body and the drill bit housed therein in a first direction for loosening a threaded connection between the drill bit and the mud motor's bit box; or in a second direction for tightening the threaded connection between the drill bit and the mud motor's bit box.
As shown in
Having reference to
As shown in
Having reference to
The upper body 16 defines an enclosure 20 for housing the drill bit 4 therein. In embodiments, the enclosure 20 is configured to a shape of the drill bit 4. The upper body 16 and the lower body 18 are connected therebetween by a rotational connection 22 (
The rotational connection 22 may be any suitable rotational connection, such as a pin connection, arcuate track or the like, which permits the upper body 16 to rotate relative to the lower body 18. The actuator 12 is operatively connected to the upper body 16 so as to move the upper body 16 for rotation about the rotational connection 22.
In an embodiment, as shown in
As one of skill will appreciate, the drill bit 4 is not continuously rotated for completely threading onto or for completely unthreading from the bit box 6. The bi-directional rotation of the upper body 16 is a short-arc or indexed rotation, typically about 30-40 degrees in either direction. The indexed rotation is sufficient to tighten the drill bit 4 to the bit box after the drill bit 4 has been manually hand-threaded onto the bit box 6 when making up the string 5. Similarly, when breaking out the drill string 5, the indexed rotation is sufficient to loosen the threaded connection so that the bit 4 can be manually hand-rotated for removal from the bit box 6.
The actuator 12 is any actuator which is actuable to impart movement to the upper body 16 relative to the lower body 18. As one of skill in the art would appreciate, the actuator 12 may be a linear actuator such as an air cylinder or a hydraulic cylinder, a screw actuator or the like or could be a worm gear arrangement or rack and pinion and the like.
In embodiments of the invention, the actuator 12 causes the upper body 16 to move in a first direction to loosen the threaded connection between the drill bit 4 and the bit box 6 when breaking out a drill string 5. Further, the actuator 12 causes the upper body 16 to move in a second direction to tighten the threaded connection between the drill bit 4 and the bit box 6 when making up the drill string 5.
As shown in
In an embodiment, as shown in
Having reference again to
In an embodiment, as seen in
Alternatively, as seen in
As can be appreciated by one of skill in the art, by mounting the hydraulic actuator 12 to act in an opposing direction relative to the bit breaker 10, compared to that described, the upper body 16 and the lower body 18 would be aligned in the make-up position and misaligned in the break-out position.
In embodiments, the upper body 16 is rotated into and out of alignment with the lower body 18 from about 30° to about 40° relative to the lower body 18. Such rotation is generally sufficient to loosen or tighten the threaded connection between the drill bit 4 and the bit box 6.
Having reference again to
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More particularly, as shown in
As described above for conventional drill string or tubular threading, with the bit breaker 10 in the make-up position (
In the case of the methodology for breaking-out a drill string 5 which incorporates a mud motor M, the drill string 5 is raised from the wellbore and tubulars which form the drill string 5 are unthreaded from the drill string 5 in a conventional manner. When the lowermost tubular 72, incorporating the mud motor M and the drill bit 4, is raised above the rig floor F, the bit breaker 10, having the upper and lower bodies 16, 18 oriented relative to one another in the break-out position, is secured to the rig floor F. The drill string 5 is lowered for engaging the drill bit 4 in the shaped enclosure 20 of the upper body 16 for securing the bit 4 therein for co-rotation with the upper body 16. The lower stationary tong 8 of the power wrench 70 is positioned to engage the mud motor's bit box 6 for holding the normally rotatable bit box 6 stationary. Thereafter, the bit breaker's actuator 12 is actuated to act on the upper body 16 causing the upper body 16 and the drill bit 4 housed therein to co-rotate from about 30° to about 40° relative to the stationary lower body 18 for loosening the threaded connection between the drill bit 4 and bit box 6.
As described above for conventional drill string, with the bit breaker 10 in the break-out position and the actuator being a double-acting hydraulic actuator, the hydraulic cylinder 32 and rod 36 act to push the upper body 16 relative to the lower body 18 for rotating the upper body 16 clockwise about the rotational connection 22. In an embodiment wherein the upper body 16 is aligned with the lower body 18 in the break-out position (
Claims
1. A bit breaker for use in threading a drill bit to or from a mud motor having a lower, normally rotatable bit box, the bit breaker comprising:
- a rotatable bit breaker body for housing the drill bit for co-rotation therewith; and
- an actuator connected between the bit breaker body and a stationary member,
- wherein,
- when the mud motor's bit box is held stationary, the actuator is actuable to co-rotate the bit breaker body and drill bit housed therein relative to the stationary member about an axis common to the drill bit, the bit breaker and the mud motor, the body being rotated
- in a first direction for loosening a threaded connection between the drill bit and the mud motor's bit box; and
- in a second direction for tightening the threaded connection between the drill bit and the mud motor's bit box.
2. The bit breaker of claim 1 wherein the bit breaker body further comprises:
- an upper body having an enclosure therein for housing the drill bit;
- a lower body held stationary for forming the stationary member; and
- a rotational connection operatively connected between the upper rotatable body and the lower stationary body for permitting rotation of the upper body relative to the lower stationary body about the common axis; and
- wherein the actuator is connected between the upper body and the lower body for moving the upper body relative to the lower body for rotation about the rotational connection in the first and second directions.
3. The bit breaker of claim 2 wherein
- the upper body is oriented relative to the lower body in a break-out position for rotating the upper body in the first direction relative to the lower body; and
- the upper body is oriented relative to the lower body in a make-up position for rotating the upper body in the second direction relative to the lower body.
4. The bit breaker of claim 3 wherein the actuator is a double-acting hydraulic actuator further comprising:
- a hydraulic cylinder pivotally connected to the lower body; and
- a rod operatively connected to the hydraulic cylinder for extension and retraction therefrom, the rod being pivotally connected at a distal end to the upper body wherein
- in the break-out position, the rod is extended to push the upper body to move relative to the stationary lower body to rotate in the first direction about the rotational connection; and
- in the make-up position, the rod is retracted to pull the upper body to move relative to the stationary lower body to rotate in the second direction about the rotational connection.
5. The bit breaker of claim 3 wherein the upper body is aligned with the lower body in the break-out position and wherein the upper body is rotated about the common axis out of alignment relative to the lower body in the make-up position.
6. The bit breaker of claim 2, for use with conventional threading, wherein when viewed from a top the first direction is a clockwise direction and the second direction is a counter-clockwise direction.
7. The bit breaker of claim 2 further comprising a connector acting between the lower body and a rig floor holding the lower body stationary for forming the stationary member.
8. The bit breaker of claim 7 wherein the connector comprises:
- a shaped projection extending from a lower surface of the lower body for engaging a corresponding shaped opening in the rig floor.
9. The bit breaker of claim 2 wherein the rotational connection operatively connected between the upper rotatable body and the lower stationary body further comprises:
- an arcuate projection; and
- an opposing, arcuate groove, wherein
- when the arcuate projection is mated in the arcuate groove and the actuator causes the upper body to move relative to the lower stationary body, the upper body rotates about the common axis.
10. The bit breaker of claim 9 wherein the arcuate projection extends upwardly from an upper surface of the lower body and the arcuate groove is formed on a lower surface of the upper body.
11. The bit breaker of claim 1 wherein the body is rotated about 30 degrees to about 40 degrees relative to the stationary member.
12. A system for applying torque to a drill bit on a mud motor with a lower, normally rotatable bit box, the system comprising:
- a bit breaker having a rotatable bit breaker body for housing the drill bit for co-rotation therewith; and an actuator connected between the bit breaker body and a stationary member, the actuator causing the body to rotate relative to the stationary member; and
- a tong for holding the bit box stationary,
- wherein,
- when the tong is actuated to hold the mud motor's bit box stationary, the actuator is actuable to co-rotate the bit breaker body and drill bit housed therein relative to the stationary member about a common axis, the body being rotated in a first direction for loosening a threaded connection between the drill bit and the mud motor's bit box; and in a second direction for tightening the threaded connection between the drill bit and the mud motor's bit box.
13. The system of claim 12 wherein the bit breaker body further comprises:
- an upper body having an enclosure therein for housing the drill bit;
- a lower body held stationary for forming the stationary member; and
- a rotational connection operatively connected between the upper rotatable body and the lower stationary body for permitting rotation of the upper body relative to the lower stationary body about the common axis; and
- wherein the actuator is connected between the upper body and the lower body for moving the upper body relative to the lower body for rotation about the rotational connection in the first and second directions.
14. The system of claim 13 wherein
- the upper body is oriented relative to the lower body in a break-out position for rotating the upper body in the first direction relative to the lower body; and
- the upper body is oriented relative to the lower body in a make-up position for rotating the upper body in the second direction relative to the lower body.
15. The system of claim 13 wherein the actuator is a double-acting hydraulic actuator further comprising:
- a hydraulic cylinder pivotally connected to the lower body; and
- a rod operatively connected to the hydraulic cylinder for extension and retraction therefrom, the rod being pivotally connected at a distal end to the upper body wherein
- in the break-out position, the rod is extended to push the upper body to move relative to the stationary lower body to rotate in a first direction about the rotational connection; and
- in the make-up position, the rod is retracted to pull the upper body to move relative to the stationary lower body to rotate in a second direction about the rotational connection.
16. The system of claim 14 wherein the upper body is aligned with the lower body in the break-out position and wherein the upper body is rotated about the common axis out of alignment relative to the lower body in the make-up position.
17. The system of claim 12, for use with conventional threading, wherein the first direction is a clockwise direction and the second direction is a counter-clockwise direction.
18. The system of claim 13 further comprising a connector acting between the lower body and a rig floor holding the lower body stationary for forming the stationary member.
19. The system of claim 18 wherein the connector comprises:
- a shaped projection extending from a lower surface of the lower body for engaging a corresponding shaped opening in the rig floor.
20. The system of claim 13 wherein the rotational connection operatively connected between the upper rotatable body and the lower stationary body further comprises:
- an arcuate projection; and
- an opposing, arcuate groove, wherein when the arcuate projection is mated in the arcuate groove and the actuator causes the upper body to move relative to the lower stationary body, the upper body rotates about the common axis.
21. The system of claim 20 wherein the arcuate projection extends upwardly from an upper surface of the lower body and the arcuate groove is formed on a lower surface of the upper body.
22. The system of claim 12 wherein the body is rotated about 30 degrees to about 40 degrees relative to the stationary member.
23. The system of claim 12 wherein the tong for holding the bit box stationary is a lower stationary tong of a power wrench.
24. A method for applying torque to a drill bit on a mud motor with a lower, normally rotatable bit box for loosening or tightening a threaded connection between the drill bit and the bit box, the method comprising:
- providing a bit breaker having a rotatable bit breaker body having an enclosure for housing the drill bit therein for co-rotation therewith; and an actuator connected between the bit breaker body and a stationary member, the actuator being actuable to cause the body to rotate relative to the stationary member about an axis common to the drill bit and the bit box;
- inserting the drill bit threaded to the bit box into the enclosure of the bit breaker body;
- engaging the bit box for holding the bit box stationary;
- actuating the actuator to co-rotate the bit breaker body and the drill bit housed therein in a first direction for loosening a threaded connection between the drill bit and the mud motor's bit box; or in a second direction for tightening the threaded connection between the drill bit and the mud motor's bit box.
25. The method of claim 24 comprising
- actuating the actuator to co-rotate the bit breaker body and the drill bit housed therein from about 30 degrees to about 40 degrees relative to the stationary member.
26. The method of claim 24 further comprising
- securing the bit breaker body to a rig floor, the rig floor being the stationary member.
27. The method of claim 24 wherein the bit breaker further comprises an upper body for housing the drill bit, a lower body, a rotational connection between the upper and lower bodies and an actuator connected therebetween for rotating the upper body relative to the lower body at the rotational connection about the common axis comprising:
- securing the lower body to a rig floor, the lower body acting as the stationary member, wherein
- the actuating the actuator moves the upper body relative to the stationary lower body causing the upper body to rotate about the common axis for rotation in the first or second direction.
Type: Application
Filed: Mar 18, 2011
Publication Date: Sep 20, 2012
Applicant: PRECISION DRILLING CORPORATION (Calgary)
Inventor: HAROLD GRIFFIN (Calgary)
Application Number: 13/051,136
International Classification: E21B 7/00 (20060101); E21B 11/00 (20060101);