Patent Application
20240125220
Any and all applications for which a foreign or domestic priority claim is identified in the Application Data Sheet as filed with the present application are hereby incorporated by reference under 37 CFR 1.57. The present application claims priority benefit of U.S. Provisional Application No. SG 10202101753Y, filed Feb. 22, 2021, the entirety of which is incorporated by reference herein and should be considered part of this specification.
The present disclosure generally relates to electric submersible pumps (ESPs), and more particularly to seals for use in ESPs.
Various types of artificial lift equipment and methods are available, for example, electric submersible pumps (ESPs). An ESP includes multiple centrifugal pump stages mounted in series, each stage including a rotating impeller and a stationary diffuser mounted on a shaft, which is coupled to a motor. In use, the motor rotates the shaft, which in turn rotates the impellers within the diffusers. Well fluid flows into the lowest stage and passes through the first impeller, which centrifuges the fluid radially outward such that the fluid gains energy in the form of velocity. Upon exiting the impeller, the fluid flows into the associated diffuser, where fluid velocity is converted to pressure. As the fluid moves through the pump stages, the fluid incrementally gains pressure until the fluid has sufficient energy to travel to the well surface.
In some configurations, an electric submersible pump includes a plurality of impellers; a plurality of diffusers; at least one sealing ring positioned axially between two consecutive diffusers of the plurality of diffusers; and at least one O-ring positioned axially between the at least one sealing ring and a lower of the two consecutive diffusers.
The impellers, diffusers, sealing ring, and O-ring can be disposed in a housing of the electric submersible pump. As the impellers, diffusers, sealing ring, and O-ring are slid into the housing during assembly, a gap is formed axially between a portion of the at least one sealing ring and an upward facing surface of the lower of the two consecutive diffusers. Once the impellers, diffusers, sealing ring, and O-ring are positioned at a desired location within the housing, stage compression is applied, thereby closing the gap such that the sealing ring contacts the upward facing surface of the lower of the two consecutive diffusers and the O-ring becomes compressed against an inner surface of the housing. When the O-ring is compressed against the inner surface of the housing, the O-ring seals against the inner surface of the housing to reduce housing-diffuser annular pressure and therefore stress on the diffusers below the seal. The pump can include a plurality of sealing rings, each positioned axially between two consecutive diffusers, and a plurality of O-rings, each positioned axially between an associated sealing ring and the lower of the two consecutive diffusers between which the associated sealing ring is positioned.
The sealing ring can have a radially inner portion and a radially outer portion. The O-ring is positioned axially between the radially outer portion and the lower of the two consecutive diffusers. A lower surface of the radially inner portion contacts an upward facing surface of the lower of the two consecutive diffusers in use. A lower edge of the radially outer portion can be angled or inclined.
In some configurations, a method of assembling an electric submersible pump includes positioning a sealing ring axially between two diffusers such that a gap is formed axially between the sealing ring and an upward facing surface of a lower diffuser of the two diffusers; positioning an uncompressed O-ring axially between the sealing ring and the lower diffuser of the two diffusers; sliding the diffusers, sealing ring, and O-ring into a housing to a desired position; and applying stage compression to close the gap, thereby compressing the O-ring to create a seal that prevents or inhibits leakage of fluid.
The method can include positioning a plurality of sealing rings each axially between two consecutive diffusers of a plurality of diffusers, positioning a plurality of uncompressed O-rings each axially between an associated sealing ring and the lower diffuser of the two consecutive diffusers between which the associated sealing ring is positioned, and sliding the plurality of diffusers, plurality of sealing rings, and plurality of O-rings into the housing to a desired position.
In some configurations, an electric submersible pump system includes an electric submersible pump, a shaft extending axially through the pump, a protector, and a motor. The pump includes a housing, a plurality of impellers, a plurality of diffusers, and at least one O-ring positioned axially between two consecutive diffusers of the plurality of diffusers.
The system can include at least one sealing ring positioned axially between the two consecutive diffusers of the plurality of diffusers. The at least one O-ring can be positioned axially between the at least one sealing ring and a lower of the two consecutive diffusers. The O-ring can be in an uncompressed state as the impellers, diffusers, sealing ring, and O-ring are slid into the housing during assembly. A gap can be formed axially between a portion of the at least one sealing ring and an upward facing surface of the lower of the two consecutive diffusers during assembly as the impellers, diffusers, sealing ring, and O-ring are slid into the housing during assembly. The sealing ring can contact the upward facing surface of the lower of the two consecutive diffusers and the O-ring can be compressed against an inner surface of the housing when the impellers, diffusers, sealing ring, and O-ring are positioned at a desired location within the housing and stage compression is applied. The sealing ring can have a radially inner portion and a radially outer portion. The O-ring can be positioned axially between the radially outer portion and the lower of the two consecutive diffusers. A lower surface of the radially inner portion can contact an upward facing surface of the lower of the two consecutive diffusers in use.
Certain embodiments, features, aspects, and advantages of the disclosure will hereafter be described with reference to the accompanying drawings, wherein like reference numerals denote like elements. It should be understood that the accompanying figures illustrate the various implementations described herein and are not meant to limit the scope of various technologies described herein.
In the following description, numerous details are set forth to provide an understanding of some embodiments of the present disclosure. It is to be understood that the following disclosure provides many different embodiments, or examples, for implementing different features of various embodiments. Specific examples of components and arrangements are described below to simplify the disclosure. These are, of course, merely examples and are not intended to be limiting. However, it will be understood by those of ordinary skill in the art that the system and/or methodology may be practiced without these details and that numerous variations or modifications from the described embodiments are possible. This description is not to be taken in a limiting sense, but rather made merely for the purpose of describing general principles of the implementations. The scope of the described implementations should be ascertained with reference to the issued claims.
As used herein, the terms “connect”, “connection”, “connected”, “in connection with”, and “connecting” are used to mean “in direct connection with” or “in connection with via one or more elements”; and the term “set” is used to mean “one element” or “more than one element”. Further, the terms “couple”, “coupling”, “coupled”, “coupled together”, and “coupled with” are used to mean “directly coupled together” or “coupled together via one or more elements”. As used herein, the terms “up” and “down”; “upper” and “lower”; “top” and “bottom”; and other like terms indicating relative positions to a given point or element are utilized to more clearly describe some elements. Commonly, these terms relate to a reference point at the surface from which drilling operations are initiated as being the top point and the total depth being the lowest point, wherein the well (e.g., wellbore, borehole) is vertical, horizontal or slanted relative to the surface.
Various types of artificial lift equipment and methods are available, for example, electric submersible pumps (ESP). As shown in the example embodiment of
The pump 112 includes multiple centrifugal pump stages mounted in series within a housing 230, as shown in
In use, well fluid flows into the first (lowest) stage of the ESP 110 and passes through an impeller 210, which centrifuges the fluid radially outward such that the fluid gains energy in the form of velocity. Upon exiting the impeller 210, the fluid makes a sharp turn to enter a diffuser 220, where the fluid's velocity is converted to pressure. The fluid then enters the next impeller 210 and diffuser 220 stage to repeat the process. As the fluid passes through the pump stages, the fluid incrementally gains pressure until the fluid has sufficient energy to travel to the well surface.
As shown in
The illustrated bearing assembly also includes an anti-rotation upthrust ring 256 disposed about the bearing sleeve 252. As shown, the anti-rotation upthrust ring 256 can be disposed adjacent an upstream end of the bushing 254. The bearing sleeve 252 is keyed or rotationally coupled to the shaft 202 such that the bearing sleeve 252 rotates with the shaft in use 202. The anti-rotation upthrust ring 256 prevents or inhibits the bushing 254 from rotating such that the bushing 254 is stationary or rotationally fixed relative to the diffuser 220. The anti-rotation upthrust ring 256 can also help prevent or inhibit axial movement of the bushing 254 and/or the bushing 254 from dropping out of place from the bearing housing 260. In use, the bearing assembly can help absorb thrust and/or accommodate the rotation of the shaft relative to the diffuser.
The pump 112 can also include one or more thrust assemblies, for example, upthrust assemblies and/or downthrust assemblies, disposed axially between portions of and/or operatively connecting an impeller 210 and its associated diffuser 220. A thrust assembly can include a thrust washer and a thrust pad, which may be a portion of the impeller 210 or diffuser 220. In the configuration of
In a typical downhole pump, the maximum number of stages within a section of the pump is typically limited because the first, or lowest, set of diffusers at the pump inlet 114 are not able to withstand the combined axial thrust and radial pressure loads generated by the stages stacked on top of them. Therefore, multiple short sections must be used instead of a single long section pump, which can increase the cost per foot of lift. To address this lower diffuser collapse issue, O-ring seals 290 are often used to seal the annular region between the OD of the diffuser 220 and the ID of the housing 230, for example as shown in
However, pumps including O-ring seals 290 can be difficult to manufacture. During assembly, the O-ring 290 is installed on the OD of the diffuser 220. Then the diffuser 220 and O-ring 290 in a compressed state are pushed through the threads at the end of the housing 230 and must travel through the ID of the housing 230 until the diffuser 220 reaches its desired position within the pump housing 230. In some cases, the diffuser 220 and O-ring 290 must travel a distance in the range of 10-20 feet to reach the desired position.
To properly function as a seal, the O-ring 290 must be squeezed against the ID of the housing 230. The O-ring 290 can therefore be damaged by sharp threads on the housing 230 or rubbed and/or extruded against the ID of the housing 230 during assembly. Assembly can become more complicated and/or have a higher likelihood of damage to the O-rings 290 if multiple stages include O-rings 290. The process of pushing multiple sets of compressed O-rings 290 through long sections of the housing 230 can generate significant friction force, making the manual assembly operation difficult.
The present disclosure provides a crush type seal design and an independent sealing ring stacking along with the pump stages, for example as shown in
An O-ring 295 is positioned axially between the sealing ring 215 and the adjacent or next lower diffuser 220. In the illustrated configuration, the O-ring 295 is positioned axially between the lower edge 217 and an upward facing surface or top face 222 of the adjacent or next lower diffuser 220. In some configurations, a pump includes a plurality of sealing rings 215, each positioned axially between a pair of consecutive diffusers, and a plurality of O-rings 295, each positioned axially between one of the sealing rings 215 and the next lower adjacent or consecutive diffuser 220.
In an initial, uncompressed state, the O-ring 295 is uncompressed, and a gap 213 is formed between the lower surface 218 of the radially inner portion 215a of the sealing ring 215 and an upward facing surface 224 of the adjacent, next lower diffuser 220. During assembly, there may be a relatively small amount of friction generated due to the axial force of pushing the stage stack into the housing 230. However, the O-ring 295 remains generally or mostly free from any compression or squeeze, and any friction generated is considerably lower than the friction force generated during assembly of pumps such as shown in
Once the diffuser 220 and sealing ring 215 are pushed into the correct or desired position within the housing 230, stage compression is applied. Stage compression can bring surface 218 into contact with surface 224, closing the gap 213, as shown in
With the design of
Language of degree used herein, such as the terms “approximately,” “about,” “generally,” and “substantially” as used herein represent a value, amount, or characteristic close to the stated value, amount, or characteristic that still performs a desired function or achieves a desired result. For example, the terms “approximately,” “about,” “generally,” and “substantially” may refer to an amount that is within less than 10% of, within less than 5% of, within less than 1% of, within less than 0.1% of, and/or within less than 0.01% of the stated amount. As another example, in certain embodiments, the terms “generally parallel” and “substantially parallel” or “generally perpendicular” and “substantially perpendicular” refer to a value, amount, or characteristic that departs from exactly parallel or perpendicular, respectively, by less than or equal to 15 degrees, 10 degrees, 5 degrees, 3 degrees, 1 degree, or 0.1 degree.
Although a few embodiments of the disclosure have been described in detail above, those of ordinary skill in the art will readily appreciate that many modifications are possible without materially departing from the teachings of this disclosure. Accordingly, such modifications are intended to be included within the scope of this disclosure as defined in the claims. It is also contemplated that various combinations or sub-combinations of the specific features and aspects of the embodiments described may be made and still fall within the scope of the disclosure. It should be understood that various features and aspects of the disclosed embodiments can be combined with, or substituted for, one another in order to form varying modes of the embodiments of the disclosure. Thus, it is intended that the scope of the disclosure herein should not be limited by the particular embodiments described above.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10202101753Y | Feb 2021 | SG | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US2022/017235 | 2/22/2022 | WO |
