ELECTRIC MOTORS AND RELATED SYSTEMS FOR DEPLOYMENT IN A DOWNHOLE WELL ENVIRONMENT
A method can include providing a motor that includes a housing, axially aligned stationary electromagnets disposed in the housing, an aperture defined by the axially aligned stationary electromagnets, movable axially aligned permanent magnets disposed in the aperture and a connector shaft connected at an end of the movable axially aligned permanent magnets; disposing the motor and a rod pump in a well; controlling operation of the motor to linearly reciprocate the axially aligned movable permanent magnets and the connector shaft; pumping fluid from the well via the rod pump responsive to the linear reciprocation of the axially aligned movable permanent magnets and the connector shaft; and substantially blocking the pumped fluid from flowing through the aperture defined by the axially aligned stationary electromagnets of the motor. Various other apparatuses, systems, methods, etc., are also disclosed.
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This application is a continuation of a co-pending U.S. patent application having Ser. No. 12/572,548, filed 2 Oct. 2009, now U.S. Pat. No. 8,587,163, issued 19 Nov. 2013, which are incorporated by reference herein.
FIELDThe present application relates to the oil field industry and more specifically to motors that supply output to an operable production device in a well, such as for example a pump, sleeve, valve or other mechanical device. The disclosures provided herein can be particularly useful in small-bore applications.
BACKGROUNDArtificial lift in wells can be achieved by the use of downhole electric motors that convert rotational motion to linear motion, or by the use of surface-bound rod pumps. Electric motors typically employ magnetic forces to create rotational motion, which is then converted to linear motion in order to provide output to an operable production device, such as a pump or other mechanical device. The conversion of rotational motion to linear motion involves failure-prone mechanisms and complex moving parts, which disadvantageously introduce efficiency and/or reliability losses to the system. This rotational-to-linear conversion is also impractical in special small-bore applications, where space constraints limit the size of the motor and therefore its output capabilities. Current non-rotational artificial lift methods, such as rod pumps, disadvantageously require surface motors and extensive shafting to couple a source of power to a downhole linear pump. These methods are not a viable option in areas where above-ground space is at a premium.
SUMMARYThe present disclosure provides improved electric motor configurations for deployment in a downhole well environment. The unique configurations employ linear reciprocating movement of a series of aligned magnets including one or more movable magnets in combination with one or more stationary magnets. This advantageously provides raw linear output, while taking up relatively little annular space in the well. This technology is thus especially suitable for use in small wellbores where other artificial lift methods are difficult to implement.
In one example, two groups of magnets are interdigitated and have opposing faces. Reversing the polarity of one of the groups of magnets causes reciprocation of the movable magnet(s) and provides linear output to the noted production device. In another example, the groups of magnets are aligned adjacent each other and the movable magnet(s) is/are movable axially between a first position proximate the outer end of one of the stationary magnets and a second position proximate the outer end of another of the stationary magnets. Reversing the polarity of one of the groups of magnets causes reciprocation of the movable magnet(s) and provides the linear output to the production device. The magnets can be, for example, disc-shaped or rod-shaped.
In broader terms, one example of the electric motor includes a housing containing a series of magnets. The series includes at least three magnets, including two outer magnets and an inner magnet disposed between the two outer magnets. The two outer magnets have inside faces with like poles and outside faces with like poles. One of the inner magnet and the two outer magnets is stationary, while the other is movable. The one of the inner magnet and the two outer magnets that is movable moves between a first position in which the inner magnet is located proximate to one of the outer two magnets, and a second position in which the inner magnet is located proximate to the other of the two outer magnets. The one of the inner magnet and the two outer magnets that is movable is configured for connection to an operable production device. A supply of alternating current is coupled to the series of magnets so as to alternate the polarity of one of the inner magnet and the two outer magnets to thereby cause the one of the inner magnet and the two outer magnets that is movable to reciprocate between the first and second positions, and to thereby provide reciprocating linear output to drive the operable production device.
Another example of the electric motor includes a housing containing a plurality of aligned magnets. The plurality of magnets includes at least two adjacent, axially-aligned stationary magnets having outer ends having the same polarity and inner ends having the same polarity. The plurality of magnets also includes at least one movable magnet disposed adjacent to, or more specifically, within the stationary magnets. The movable magnet is movable axially between a first position proximate the outer end of one of the stationary magnets and a second position proximate the outer end of the other stationary magnet. The movable magnet is configured for connection to an operable production device in the well. A supply of alternating current is coupled to the plurality of magnets so as to alternate the polarity of one of the movable and stationary magnets to thereby cause the movable magnet to reciprocate between the first and second positions, and to thereby provide reciprocating linear output to drive the operable production device.
Downhole well pumping systems for artificial lift are also provided. The systems include a production pump disposed in a downhole well environment and an electric motor coupled to the production pump and operable to provide reciprocating linear output to drive the production pump. The configuration of the electric motor can be that of either of the two examples described above. A controller is configured to control operation of the electric motor by selectively supplying alternating current to the electric motor and to thereby provide reciprocating linear output to drive the operable production device.
A best mode is described herein below with reference to the following drawing figures.
In the following description, certain terms have been used for brevity, clearness, and understanding. No unnecessary limitations are to be implied therefrom beyond the requirement of the prior art because such terms are used for descriptive purposes and are intended to be broadly construed. The different configurations described herein may be used alone or in combination with other configurations and systems. Various equivalents, alternatives, and modifications are possible within the scope of the appended claims.
In the example shown, the magnets 26a-26c are stationary magnets, while the magnets 28a, 28b are movable magnets. The outer magnets 26a-26c are fixed in relation to the housing 32 and thus remain stationary relative to the housing 32. In contrast, the inner magnets 28a, 28b are movable in the axial direction (A) and movable relative to the outer magnets 26a-26c between first and second positions shown in
In the example shown, the movable magnet 28a is connected to the movable magnet 28b by a connector shaft 30b. Another connector shaft 30a connects the movable magnet 28a and the movable magnet 28b to the operable production device 20 (schematically shown in dashed lines) in such a manner that movement of the magnets 28a, 28b is conveyed to the operable production device 20. Another connector shaft 30c is also provided and is optionally removably connected to another series of magnets 31 (schematically shown in dashed lines) to increase or decrease productive output of the motor 18. In this unique modular design, the amount of linear output provided to the device 20 can be easily increased by adding additional series of magnets 31 to the motor 18a in a stacked formation and easily decreased by subtracting additional series of magnets 31 from the formation. The three connector shafts 30a-30c are separate, but could alternately be replaced with a single connector shaft extending through and/or around the various magnets in the series 23.
In the example shown, the source of power 17 is connected to the stationary outer magnets 26a-26c by a wired link 21, preferably wired through the housing 32, to provide a supply of alternating current to the magnets 26a-26c and to thereby cause the poles of the magnets 26a-26c to alternate between the orientation in which the opposing faces of 26a, 26b have like south poles and the opposing faces of 26b, 26c have like north poles (shown in
Providing alternating current to alternate the polarity of the outer magnets 26a-26c thereby causes the inner magnets 28a, 28b to reciprocate back and forth between the noted first position (
In another example, the source of power 17 could be connected to the movable magnets 28a, 28b to alternate their polarity but not the polarity of the stationary magnets 26a-26c, and to thereby cause the same reciprocation of the magnets 28a, 28b described above. It is to be understood that the three magnets 26a-26c could be movable, while the magnets 28a, 28b could be stationary. The polarity of either the magnets 28a, 28b or the magnets 26a-26c could be alternated in this configuration as well to provide reciprocating linear output to the operable production device 20.
It is also to be understood that the configuration in
The electric motor 18a may have various geometries, examples of which are shown in
The movable magnet 50 and connector shafts 60a, 60b are configured such that they substantially block any fluid from flowing through the through-going aperture 54. This provides an advantage over the prior art, in which fluid can come into direct contact with the magnets in the housing and the magnets connected to the shaft. Fluids pumped from wells often contain small metallic pieces that stick to permanent magnets in the motor, and eventually clog the motor. By preventing fluid from flowing through the through-going aperture 54, this will not occur.
In the example shown, the source of power 17 is connected to the stationary magnets 48a, 48b by a wired link 21 to provide a supply of alternating current to the magnets 48a, 48b and to thereby cause the poles of the magnets 48a, 48b to alternate between the orientation in which the inner ends of the stationary magnets 48a, 48b are north poles (shown in
In another example, the source of power 17 is connected to the movable magnet 50 by a wired link 21 to alternate the polarity of the movable magnet 50 and thereby cause the same reciprocation of the movable magnet 50 as described above. However, this is not preferable because providing power to the movable magnet 50 would require that the wired link 21 reciprocate along with the movable magnet 50. Over time, this causes the wired link 21 to wear out, necessitating repair of the electric motor 18. Therefore, it is preferable that the movable magnet 50 be a permanent magnet, which does not require a wired link 21 to supply it with power.
Claims
1. A method comprising:
- providing a controller;
- providing a rod pump;
- providing a motor that comprises a housing, axially aligned stationary electromagnets disposed in the housing, an aperture defined by the axially aligned stationary electromagnets, movable axially aligned permanent magnets disposed in the aperture and a connector shaft connected at an end of the movable axially aligned permanent magnets;
- coupling the motor to the rod pump via the connector shaft;
- disposing the motor and the rod pump in a well;
- controlling operation of the motor by selectively supplying alternating current to the axially aligned stationary electromagnets via a power source controlled by the controller to linearly reciprocate the axially aligned movable permanent magnets and the connector shaft;
- pumping fluid from the well via the rod pump responsive to the linear reciprocation of the axially aligned movable permanent magnets and the connector shaft; and
- substantially blocking the pumped fluid from flowing through the aperture defined by the axially aligned stationary electromagnets of the motor.
2. The method of claim 1 comprising providing a position sensor and sensing position of the axially aligned movable permanent magnets.
3. The method of claim 1 further comprising providing another connector shaft at the other end of the axially aligned permanent magnets and connecting another moveable permanent magnet to the axially aligned permanent magnets via the other connector shaft.
4. The method of claim 1 wherein the well extends from a surface into a well environment and wherein the disposing the motor and the rod pump in the well comprises disposing the motor and the rod pump horizontally with respect to the surface.
5. The method of claim 1 wherein the controller comprises a memory and programmable code wherein the programmable code is executable for controlling operation of the motor.
6. The method of claim 1 wherein the controller is provided at a surface and is communicatively attached to a source of power via a wired link.
7. The method of claim 1 wherein the controller is provided at a surface and is communicatively attached to a source of power via a wireless link.
8. The method of claim 1 wherein the controller is attached directly to the motor.
9. The method of claim 1 wherein the connector shaft comprises an annular component for substantially blocking the pumped fluid from flowing through the aperture defined by the axially aligned stationary electromagnets of the motor.
10. The method of claim 1 wherein the substantially blocking the pumped fluid from flowing through the aperture defined by the axially aligned stationary electromagnets of the motor prevents clogging of the axially aligned permanent magnets disposed in the aperture defined by the axially aligned stationary electromagnets of the motor.
11. The method of claim 1 wherein the pumped fluid comprises a fluid from a reservoir.
12. A method comprising:
- providing a controller;
- providing a rod pump;
- providing a motor that comprises a housing, axially aligned stationary electromagnets disposed in the housing, an aperture defined by the axially aligned stationary electromagnets, movable axially aligned permanent magnets disposed in the aperture and a connector shaft connected at an end of the movable axially aligned permanent magnets;
- coupling the motor to the rod pump via the connector shaft;
- disposing the motor and the rod pump in a well;
- controlling operation of the motor by selectively supplying alternating current to the axially aligned stationary electromagnets via a power source controlled by the controller to linearly reciprocate the axially aligned movable permanent magnets and the connector shaft;
- pumping fluid from the well via the rod pump responsive to the linear reciprocation of the axially aligned movable permanent magnets and the connector shaft; and
- preventing clogging of the axially aligned permanent magnets disposed in the aperture defined by the axially aligned stationary electromagnets of the motor by substantially blocking the pumped fluid from flowing through the aperture defined by the axially aligned stationary electromagnets of the motor.
13. The method of claim 12 wherein the pumped fluid comprises metallic pieces.
14. The method of claim 13 wherein the metallic pieces are attracted to a magnet.
15. The method of claim 12 wherein the pumped fluid comprises a fluid from a reservoir.
Type: Application
Filed: Nov 16, 2013
Publication Date: May 29, 2014
Applicant: SCHLUMBERGER TECHNOLOGY CORPORATION (Sugar Land, TX)
Inventor: Alejandro Camacho Cardenas (Missouri City, TX)
Application Number: 14/082,127
International Classification: E21B 43/12 (20060101);