Coupling For Downhole Tools
Transferring rotary power between a first rotating member and a second rotating member may performed by using a first element associated with the first rotating member; and a second element associated with the second rotating member. The first element and the second element may be configured to rotate the first rotating member either substantially synchronously or non-synchronously with the second rotating member. A hysteresis material may be utilized in either or both of the first element and the second element. A modulator may be used to control a speed of the first element or the second element.
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1. Field of the Disclosure
This disclosure relates generally to oilfield downhole tools and more particularly to methods and devices for transferring a rotary motion to a consumer.
2. Description of the Related Art
To obtain hydrocarbons such as oil and gas, boreholes or wellbores are drilled by rotating a drill bit attached to the bottom of a BHA (also referred to herein as a “Bottom Hole Assembly” or (“BHA”). The BHA is attached to the bottom of a tubing, which is usually either a jointed rigid pipe or a relatively flexible spoolable tubing commonly referred to in the art as “coiled tubing.” The string comprising the tubing and the BHA is usually referred to as the “drill string.” When jointed pipe is utilized as the tubing, the drill bit is rotated by rotating the jointed pipe from the surface and/or by a mud motor contained in the BHA. In the case of a coiled tubing, the drill bit is rotated by the mud motor. BHA's, as well as other wellbore devices, may often incorporate equipment that require the transfer of rotary power from a generator to a consumer; e.g., from a turbine to an oil pump. The transfer of such rotary power often occurs across two or more rotating members such as shafts. Conventional couplings or gears may utilize magnetic contact between input side and output side. The couplings may utilize Permanent Magnet Synchronous Couplings (PMSC). Such couplings have input drive and an output drive coupled magnetically by using permanent magnets. As long as the maximum torque is not exceeded, both parts of the coupling run synchronously. When the torque is exceeded, the coupling de-couples such that no meaningful rotary power is conveyed across the coupling.
The present disclosure addresses the need for couplings that provide enhanced control over the transfer of rotary power between two or more rotating elements.
SUMMARY OF THE DISCLOSUREIn aspects, the present disclosure provides an apparatus for transferring rotary power between a first rotating member and a second rotating member. In one embodiment, the apparatus may include a first element associated with the first rotating member; and a second element associated with the second rotating member. The first element and the second element may be configured to rotate the first rotating member either substantially synchronously or non-synchronously with the second rotating member. In arrangements, a magnetic field may connect the first element with the second element. Also, the first rotating member and the second rotating member may shift from a synchronous rotation to a non-synchronous rotation when a predetermined torque value is applied by the first rotating member to the second rotating member. In arrangements, the apparatus may include a modulator that controls a rotational speed of the second rotating member. The modulator may reduce a strength of a magnetic field connecting the first element and the second element. In some applications, the modulator may be an eddy current brake connected to the second rotating member, an oil-pump and nozzle, or an additional load imposed by a consumer such as an alternator. In embodiments, the first element circumferentially surrounds the second element. Also, the second rotating member may be substantially isolated from a drilling fluid. In arrangements, the first element and the second element may be further configured to rotate the second rotating member at a substantially constant speed that is greater than zero when the first rotating member rotates non-synchronously with the second rotating member.
In aspects, the present disclosure provides a method for transferring rotary power between a first rotating member and a second rotating member. The method may include coupling the first rotating member to the second rotating member, rotating the first rotating member substantially synchronously with the second rotating member; and rotating the first rotating member substantially non-synchronously with the second rotating member when the first rotating member exceeds a specified rotary speed. In embodiments, the method may include rotating the second rotating member at a substantially constant speed after the first rotating member exceeds the specified rotary speed. The method may also include rotating the first rotating member at a speed greater than the substantially constant speed. The coupling may utilize a magnetic field and the method may include shifting the first rotating member and the second rotating member from a synchronous rotation to a non-synchronous rotation when a predetermined torque value is applied by the first rotating member to the second rotating member. Illustrative methods may further include modulating a rotational speed of the second rotating member. The modulating may reduce a magnetic field connecting the first element and the second element. The method may further include substantially isolating the second rotating member from a drilling fluid. In arrangements, the method may include rotating the second element at a substantially constant speed that is greater than zero when the first element rotates non-synchronously with the second element.
In embodiments, the present disclosure provides a system for transferring rotary power. The system may include a rotary power generator having a first rotating member, a consumer having a second rotating member, and a coupling connecting the first rotating member to the second rotating member. The coupling may be configured to rotate the first rotating member substantially synchronously and non-synchronously with the second rotating member. Either the first rotating member or the second rotating member may include a hysteresis material. In arrangements, a magnetic field connects the first rotating member and the second rotating member. Also, the first rotating member and the second rotating member may shift from a synchronous rotation to a non-synchronous rotation when a predetermined torque value is applied by the first rotating member to the second rotating member. In arrangements, the system may include a modulator that controls a rotational speed of the second rotating member. The modular may reduce a magnetic field connecting the first rotating member and the second rotating member.
Illustrative examples of some features of the disclosure thus have been summarized rather broadly in order that the detailed description thereof that follows may be better understood, and in order that the contributions to the art may be appreciated. There are, of course, additional features of the disclosure that will be described hereinafter and which will form the subject of the claims appended hereto.
For detailed understanding of the present disclosure, references should be made to the following detailed description of the preferred embodiment, taken in conjunction with the accompanying drawings, in which like elements have been given like numerals and wherein:
The present disclosure relates to devices and methods for selectively coupling a driving rotating member to a driven rotating member. The present disclosure is susceptible to embodiments of different forms. The drawings show and the written specification describes specific embodiments of the present disclosure with the understanding that the present disclosure is to be considered an exemplification of the principles of the disclosure, and is not intended to limit the disclosure to that illustrated and described herein.
As will be apparent from this disclosure, the present teachings provide enhanced control over connections between two or more rotating members. While the present teachings may be advantageously applied to any number of applications, for clarity and ease of explanation, reference will be made to
In
Referring now to
In one embodiment, the coupling 100 transfers rotary power from the driving or input section 110 to the driven or output section 120. In embodiments, the sections 110 and 120 may include flexible shafts, tubes, rods or other suitable tubular rotary power transmission elements. The driving or input section 110 may include an energy source such as a turbine 112 that is energized by a flow of drilling fluid. The driving section 110 may also be energized by the rotation of the drill string or drill bit. A load 130, which may be an oil pump 132, is coupled to output section 120 via a shaft 122.
Referring now to
It should therefore be appreciated that the coupling 100 provides meaningful or operation rotary power transfer across an extended rotary speed range. Moreover, the speed may be controlled such that the consumer is not driven at an undesirable speed. While two speed ranges are shown, it should be understood that the coupling 100 may be configured to have three or more operating speeds. That is, in a first input speed range, output speed may vary directly with input speed, in a second input speed range, a first steady output speed is maintained; in a third input speed range, a second steady output speed is maintained, etc.
In embodiments, the values for the transition value at point 144 and the total or complete decoupling at point 152 may be selected based on the operation characteristics or limitations of the load 140. As noted previously, the load 140 may be any consumer of rotary power such as an alternator that generates electricity, an oil pump that supplies pressurized fluid, or a cutting tool that uses rotary power to disintegrate a formation, a wall of a wellbore tubular, or any other material found in a wellbore.
Referring now to
In some embodiments, an electrically conductive material may used as the hysteresis material. Such material may display or exhibit a torque characteristic associated with eddy current coupling. This torque characteristic may be reduced or eliminated through known lamination techniques, e.g., like a winding stack of an electrical motor or alternator.
Referring now to
Referring now to
In one embodiment, the modulator 160 may be configured to control or rectify a rotary speed of the output shaft 122. The modular 160 may include a winding section 162, a permanent magnet section 163 that surrounds the winding section 162, and coils 164 that are electrically coupled to the winding section 162. In this case, the winding section 162 rotates inside a stationary permanent magnet section 160. In embodiments, a rotating rectifier 166 may be utilized to rectify the AC-Current of the winding section 162 before leading it to the coils 164. In other arrangements, the current may be regulated via electronics (either rotating or non-rotating) before leading it to the coils (not shown). The rotation of the shaft 122 causes the windings section 162 to generate a voltage that is applied to the coils 164. In response to the applied voltage, the coils 164 produce a magnetic field that weakens the field of the permanent magnets 104. Weakening the magnetic field of the permanent magnets 104 reduces the magnetic torque capability between the hysteresis ring 102 and permanent magnets 104. The reduced strength of the magnetic field shifts the point of de-synchronization to lower torque between the input section 110 and the output section 120. The magnitude of the voltage is dependent on the speed of the shaft 122; e.g., the voltage varies directly with the rotation speed. Therefore, as the speed of the output section 120 increases, the differential in the rotational speeds of the input section 110 and the output section 120 increases due to the increased slippage. It should be appreciated that appropriate configuration of the modulator 160 may yield a relatively constant input speed for the shaft 122 that drives the load 124.
Referring now to
Referring now to
Additional modulator may include an oil-pump that pumps fluid through a flow restriction element such as a nozzle, an alternator that may be load-controlled by electronics in addition to the required output power just to limit the speed; and any other devise that exhibit a strong progressive torque versus speed.
From the above, it should be appreciated that what has been described includes, in part, an apparatus for transferring rotary power between a first rotating member and a second rotating member. The rotary power may be generated by any suitable generator and the rotary power may be utilized, either directly or indirectly, by a variety of downhole power consumption devices. The apparatus may include a first element associated with the first rotating member; and a second element associated with the second rotating member. The first element and the second element may be configured to rotate the first rotating member either substantially synchronously or non-synchronously with the second rotating member. In arrangements, a magnetic field may connect the first element with the second element. Also, the first rotating member and the second rotating member may shift from a synchronous rotation to a non-synchronous rotation when a predetermined torque value is applied by the first rotating member to the second rotating member. In arrangements, the apparatus may include a modulator that controls a rotational speed of the second rotating member. The modulator may reduce a strength of a magnetic field connecting the first element and the second element. In some applications, the modulator may be an eddy current brake connected to the second rotating member, an oil-pump and nozzle, or an additional alternator load. In embodiments, the first element circumferentially surrounds the second element. Also, the second rotating member may be substantially isolated from a drilling fluid. In arrangements, the first element and the second element may be further configured to rotate the second rotating member at a substantially constant speed that is greater than zero when the first rotating member rotates non-synchronously with the second rotating member.
From the above, it should be appreciated that what has been described includes, in part, a method for transferring rotary power between a first rotating member and a second rotating member. The method may include coupling the first rotating member to the second rotating member, rotating the first rotating member substantially synchronously with the second rotating member; and rotating the first rotating member substantially non-synchronously with the second rotating member when the first rotating member exceeds a specified rotary speed. In embodiments, the method may include rotating the second rotating member at a substantially constant speed after the first rotating member exceeds the specified rotary speed. The method may also include rotating the first rotating member at a speed greater than the substantially constant speed. The coupling may utilize a magnetic field and the method may include shifting the first rotating member and the second rotating member from a synchronous rotation to a non-synchronous rotation when a predetermined torque value is applied by the first rotating member to the second rotating member. Illustrative methods may further include modulating a rotational speed of the second rotating member. The modulating may reduce a magnetic field connecting the first element and the second element. The method may further include substantially isolating the second rotating member from a drilling fluid. In arrangements, the method may include rotating the second element at a substantially constant speed that is greater than zero when the first element rotates non-synchronously with the second element.
From the above, it should be appreciated that what has been described includes, in part, a system for transferring rotary power. The system may include a rotary power generator having a first rotating member, a consumer having a second rotating member, and a coupling connecting the first rotating member to the second rotating member. The coupling may be configured to rotate the first rotating member substantially synchronously and non-synchronously with the second rotating member. Either the first rotating member or the second rotating member may include a hysteresis material. In arrangements, a magnetic field connects the first rotating member and the second rotating member. Also, the first rotating member and the second rotating member may shift from a synchronous rotation to a non-synchronous rotation when a predetermined torque value is applied by the first rotating member to the second rotating member. In arrangements, the system may include a modulator that controls a rotational speed of the second rotating member. The modular may reduce a magnetic field connecting the first rotating member and the second rotating member.
The foregoing description is directed to particular embodiments of the present disclosure for the purpose of illustration and explanation. It will be apparent, however, to one skilled in the art that many modifications and changes to the embodiment set forth above are possible without departing from the scope of the disclosure. It is intended that the following claims be interpreted to embrace all such modifications and changes.
Claims
1. An apparatus for transferring rotary power between a first rotating member and a second rotating member, comprising:
- a first element associated with the first rotating member; and
- a second element associated with the second rotating member, the first element and the second element being configured to rotate the first rotating member substantially synchronously and non-synchronously with the second rotating member.
2. The apparatus of claim 1 wherein one of the first element and the second element includes a hysteresis material.
3. The apparatus of claim 1 wherein a magnetic field connects the first element and the second element, the first and the second element being configured to shift wherein the first rotating member and the second rotating member from a synchronous rotation to a non-synchronous rotation when a predetermined torque value is applied by the first rotating member to the second rotating member.
4. The apparatus of claim 1 further comprising a modulator configured to control a rotational speed of the second rotating member.
5. The apparatus of claim 4 wherein the modulator is configured to reduce a magnetic field connecting the first element and the second element.
6. The apparatus of claim 4 wherein the modulator is one of: (i) an eddy current brake connected to the second rotating member, (ii) an oil-pump and nozzle; and (iii) an additional alternator load.
7. The apparatus of claim 1 wherein the first element circumferentially surrounds the second element.
8. The apparatus of claim 1 wherein the second rotating member is substantially isolated from a drilling fluid.
9. The apparatus of claim 1 wherein the first element and the second element are further configured to rotate the second rotating member at a substantially constant speed that is greater than zero when the first rotating member rotates non-synchronously with the second rotating member.
10. A method for transferring rotary power between a first rotating member and a second rotating member, comprising:
- coupling the first rotating member to the second rotating member;
- rotating the first rotating member substantially synchronously with the second rotating member; and
- rotating the first rotating member substantially non-synchronously with the second rotating member when the first rotating member exceeds a specified rotary speed.
11. The method of claim 10, further comprising:
- rotating the second rotating member at a substantially constant speed after the first rotating member exceeds the specified rotary speed.
12. The method of claim 11 further comprising rotating the first rotating member at a speed greater than the substantially constant speed.
13. The method of claim 10, wherein the coupling is via a magnetic field; and further comprising:
- shifting the first rotating member and the second rotating member from a synchronous rotation to a non-synchronous rotation when a predetermined torque value is applied by the first rotating member to the second rotating member.
14. The method of claim 10 further comprising a modulating a rotational speed of the second rotating member.
15. The method of claim 14 wherein the modulating reduces a magnetic field connecting the first element with the second element.
16. The method of claim 10 further comprising substantially isolating the second rotating member from a drilling fluid.
17. The method of claim 10 further comprising rotating the second element at a substantially constant speed that is greater than zero when the first element rotates non-synchronously with the second element.
18. A system for transferring rotary power, comprising:
- a rotary power generator having a first rotating member;
- a consumer having a second rotating member; and
- a coupling connecting the first rotating member to the second rotating member, the coupling being configured to rotate the first rotating member substantially synchronously and non-synchronously with the second rotating member.
19. The system of claim 18 wherein one of the first rotating member and the second rotating member includes a hysteresis material.
20. The system of claim 18 wherein a magnetic field connects the first rotating member and the second rotating member, and wherein the first rotating member and the second rotating member shift from a synchronous rotation to a non-synchronous rotation when a predetermined torque value is applied by the first rotating member to the second rotating member.
Type: Application
Filed: Oct 23, 2008
Publication Date: Apr 29, 2010
Applicant: Baker Hughes Incorporated (Houston, TX)
Inventor: Eckard Scholz (Eldingen)
Application Number: 12/256,968
International Classification: E21B 31/06 (20060101);