Patent Application
20250020025
This disclosure relates generally to positive displacement fluid motors and, in an example described below, more particularly provides a Moineau-type fluid motor with enhanced operational longevity.
A Moineau-type positive displacement fluid motor includes a rotor having a number of external helical profiles or “lobes,” and a stator having a number of internal helical profiles or lobes. The number of lobes in the stator is typically greater than the number of lobes on the rotor.
A positive displacement fluid motor can be used to rotate a drill bit, mill or other tool in a well. In that case, a fluid is typically flowed through a tubular string to the fluid motor, thereby causing the rotor to rotate within the stator.
It will, therefore, be readily appreciated that improvements are continually needed in the art of constructing and utilizing positive displacement fluid motors. The present disclosure provides such improvements, which may be used in a variety of different environments and for a variety of different purposes.
Representatively illustrated in
In the
However, in other examples a wellbore may not be further drilled using the principles of this disclosure. The principles of this disclosure could, for example, be used in operations other than drilling, such as, a milling operation. The principles of this disclosure could be used to reduce friction between the tubular string 12 and the wellbore 14, or to produce vibration or fluid pulses (for example, as described in U.S. Pat. No. 11,525,307). Thus, the principles of this disclosure are not limited to well drilling operations or to use of a fluid motor with any well.
The drill bit 16 is part of a bottom hole assembly 18 connected at the distal end of the tubular string 12. In the
The fluid motor 20 is operated by fluid flow 26 through the tubular string 12 (for example, using a pump connected to the tubular string at surface). The fluid flow 26 passes through the bottom hole assembly 18, exits through nozzles in the drill bit 16 and returns via an annulus 28 formed between the tubular string 12 and the wellbore 14.
The fluid flow 26 causes a rotor in the fluid motor 20 to rotate in a stator of the fluid motor. The rotor in this example rotates with an eccentric (or rotational and orbital) motion in the stator. The flexible joint assembly 22 “converts” the eccentric motion to concentric (or only rotational) motion suitable for driving the drill bit 16. The bearing assembly 24 rotationally and axially supports an internal shaft connected between the flexible joint assembly 22 and the drill bit 16. Other or different components may be used in other examples.
The
Referring additionally now to
In the
The fluid flow 26 between the rotor 30 and the stator 32 causes the rotor to rotate in the stator. A distal end of the rotor 30 is connected to a flexible joint 36 in the flexible joint assembly 22. The flexible joint 36 allows the rotor 30 to orbit as it rotates in the stator 32, while a distal end of the flexible joint is constrained by the bearing assembly 24 to only rotate (i.e., without also orbiting).
As depicted in
As mentioned above, the bearing assembly 24 constrains a distal end of the flexible joint 36 to rotate without also orbiting. In this example, the bearing assembly 24 also reacts thrust loads, so that the rotor 30 remains appropriately positioned in the stator 32, the flexible joint 36 remains appropriately positioned in the outer housing 40, and so that thrust loads can be applied to the drill bit 16 in the
For these purposes, the bearing assembly 24 includes bearings 42 in an outer housing 44 for rotationally and axially supporting an internal drive shaft 46. An upper end of the internal drive shaft 46 is connected to the distal end of the flexible joint 36. Other bearing assembly configurations may be used in other examples, or no bearing assembly may be used.
A lower connector 48 is provided at a distal end of the drive shaft 46 in this example. The lower connector 48 is suitably configured to connect to the drill bit 16 in the
Referring additionally now to
As depicted in
The internal helical profiles 54 are positioned between opposite ends 56, 58 of the outer housing 52. However, the internal helical profiles 54 are not located equidistant from the opposite ends 56, 58. Instead, the internal helical profiles 54 are closer to the housing end 56 than they are to the housing end 58.
In the
The stator housing 52 is reversible, so that the internal helical profiles 54 can engage different sections of the rotor external helical profiles 50, depending on the orientation of the stator housing on the rotor 30. In the
In the
It can be advantageous to reverse the stator 32 on the rotor 30. For example, in one method that may be used with the
In some examples, it may not be necessary to disconnect the rotor 30 from the flexible joint 36 when the stator 32 is reversed on the rotor. End connections at the opposite ends 56, 58 of the stator housing 52 can be configured the same, and the upper connector 34 lower connection and housing 40 upper connection can be configured the same, for convenient reversing of the stator housing 52 between the upper connector 34 and housing 40.
Referring additionally now to
In the
As depicted in
Each of the end connections 62, 64 includes threads 66 and a seal portion 68 (in this example, a seal bore). The threads 66 and seal portion 68 are the same in the end connections 62, 64.
However, in other examples other types or configurations of end connections may be used. For example, the threads 66 could be external threads instead of internal threads, or the seal portion 68 could include a seal (such as, an o-ring) or an external seal surface instead of a seal bore. The scope of this disclosure is not limited to use of any particular type of end connections, or to any particular combination of elements in the end connections.
Referring additionally now to
The
In the
It has been observed by the present inventor that the section of the internal helical profiles 54 that engages the lower section of the external helical profiles 50 in operation more rapidly wears as compared to the section of the internal helical profiles that engages the upper section of the external helical profiles. By reversing the stator 32 on the rotor 30 after a first time period of operation, the less worn section of the internal helical profiles 54 that previously engaged the upper section of the external helical profiles 50 can then engage the lower section of the external helical profiles, and the more worn section of the internal helical profiles 54 that previously engaged the lower section of the external helical profiles 50 can then engage the upper section of the external helical profiles, thereby permitting the useful life of the fluid motor 20 to be extended.
It may now be fully appreciated that the above disclosure provides significant advancements to the art of constructing and utilizing positive displacement fluid motors. In examples described above, the stator 32 can be reversed on the rotor 30 after an initial time period of operation, to thereby extend the useful life of the fluid motor 20.
The above disclosure provides to the art a positive displacement fluid motor 20. In one example, the fluid motor 20 can include a stator 32, and a rotor 30 configured to rotate in response to fluid flow 26 between the stator 32 and the rotor 30. The stator 32 comprises a housing 52 and at least one internal helical profile 54 disposed between first and second end connections 62, 64 at respective first and second opposite ends 56, 58 of the housing 52, the first end connection 56 being the same as the second end connection 58.
The rotor 30 may have at least one external helical profile 50 configured to engage the stator housing internal helical profile 54. The internal helical profile 54 may be spaced apart from the first end connection 62 a first distance, the internal helical profile 54 may be spaced apart from the second end connection 64 a second distance, and the first and second distances may be the same. The first and second distances may be different.
Each of the first and second end connections 62, 64 may comprise threads 66 and a seal portion 68. The threads 66 may comprise internal threads. The seal portion 68 may comprise a seal bore.
The internal helical profile 54 may be formed on an elastomer or a metal material.
The stator housing 52 may be configured to receive the rotor 30 into the first end connection 62, and the stator housing 52 may be configured to receive the rotor 30 into the second end connection 64.
The above disclosure also provides to the art a method of utilizing a fluid motor 20 with a subterranean well. In one example, the method can comprise: deploying the fluid motor 20 into the well; operating the fluid motor 20 by fluid flow 26 between a rotor 30 and a stator 32 of the fluid motor 20; retrieving the fluid motor 20 from the well; and then reversing the stator 32 on the rotor 30.
The rotor 30 may be received into a first end connection 62 of a housing 52 of the stator 32 in the deploying step. The reversing step may comprise receiving the rotor 30 into a second end connection 64 of the stator housing 52.
The stator 32 may comprise first and second end connections 62, 64. In the deploying step, the first end connection 62 may be directly connected to a housing 40 surrounding a flexible joint 36, and the reversing step may comprise directly connecting the second end connection 64 to the housing 40.
The rotor 30 may remain connected to the flexible joint 36 during the reversing step. In other examples, the rotor 30 may be disconnected from the flexible joint 36 in the reversing step.
The reversing step may comprise withdrawing the rotor 30 from a first end connection 62 of a housing 52 of the stator 32, and inserting the rotor 30 into a second end connection 64 of the housing 52. The first end connection 62 may be configured the same as the second end connection 64.
At least one internal helical profile 54 may be disposed in the housing 52. The internal helical profile 54 may be spaced apart from the first end connection 62 a first distance, the internal helical profile 54 may be spaced apart from the second end connection 64 a second distance, and the first and second distances may be the same. The first and second distances may be different.
The stator 32 may comprise a housing 52 having first and second opposite ends 56, 58. The operating step may comprise the fluid flow 26 into the second end 58 and out of the first end 56, and the method may further comprise the fluid flow 26 into the first end 56 and out of the second end 58 after the reversing step.
Also described above is a positive displacement fluid motor 20 that can include a stator 32 and a rotor 30 configured to rotate in response to fluid flow 26 between the stator 32 and the rotor 30. The stator 32 may comprise a housing 52 and at least one internal helical profile 54 disposed between first and second end connections 62, 64 at respective first and second opposite ends 56, 58 of the housing 52. The stator housing 52 may be configured to receive the rotor 30 into the first end connection 62, and the stator housing 52 may be configured to receive the rotor 30 into the second end connection 64.
Although various examples have been described above, with each example having certain features, it should be understood that it is not necessary for a particular feature of one example to be used exclusively with that example. Instead, any of the features described above and/or depicted in the drawings can be combined with any of the examples, in addition to or in substitution for any of the other features of those examples. One example's features are not mutually exclusive to another example's features. Instead, the scope of this disclosure encompasses any combination of any of the features.
Although each example described above includes a certain combination of features, it should be understood that it is not necessary for all features of an example to be used. Instead, any of the features described above can be used, without any other particular feature or features also being used.
It should be understood that the various embodiments described herein may be utilized in various orientations, such as inclined, inverted, horizontal, vertical, etc., and in various configurations, without departing from the principles of this disclosure. The embodiments are described merely as examples of useful applications of the principles of the disclosure, which is not limited to any specific details of these embodiments.
In the above description of the representative examples, directional terms (such as “above,” “below,” “upper,” “lower,” “upward,” “downward,” etc.) are used for convenience in referring to the accompanying drawings. However, it should be clearly understood that the scope of this disclosure is not limited to any particular directions described herein.
The terms “including,” “includes,” “comprising,” “comprises,” and similar terms are used in a non-limiting sense in this specification. For example, if a system, method, apparatus, device, etc., is described as “including” a certain feature or element, the system, method, apparatus, device, etc., can include that feature or element, and can also include other features or elements. Similarly, the term “comprises” is considered to mean “comprises, but is not limited to.”
Of course, a person skilled in the art would, upon a careful consideration of the above description of representative embodiments of the disclosure, readily appreciate that many modifications, additions, substitutions, deletions, and other changes may be made to the specific embodiments, and such changes are contemplated by the principles of this disclosure. For example, structures disclosed as being separately formed can, in other examples, be integrally formed and vice versa. Accordingly, the foregoing detailed description is to be clearly understood as being given by way of illustration and example only, the spirit and scope of the invention being limited solely by the appended claims and their equivalents.
