Bearing Assemblies, Apparatuses, Devices, Systems, and Methods Includingbearings

This application is a divisional of U.S. patent application Ser. No. 18/095,490, filed Jan. 10, 2023, for “DOWNHOLE CENTRIFUGAL PUMPS INCLUDING LOCKING FEATURES AND RELATED COMPONENTS AND METHODS,” the disclosure of which is incorporated herein in its entirety by reference.

The present disclosure generally relates to pumps and, in particular, to pump diffusers of a downhole centrifugal pump including one or more locking features for at least partially resisting rotational movement of components of the diffusers relative to another component of the pump during the operation of a downhole centrifugal pump system.

Submersible pumps are generally used to provide “artificial lift” or artificial methods that increase upward fluid flow from downhole sources, such as production wells. In most instances, submersible pumps include a motor portion that drives a shaft coupled to impellers which are in turn rotationally coupled to diffusers. The impellers and diffusers are alternatingly situated around the shaft in a manner that causes fluid to flow from one impeller into a diffuser, and from the diffuser into another impeller as the shaft rotates. This process of fluid transfer from impeller to diffuser, and from diffuser to an adjacent upper impeller, repeats until the fluid travels from the downhole source to an upper destination.

Impellers are designed to accelerate fluid flow upwardly as the fluid is input into the pump from a fluid inlet. Diffusers are built to direct fluid flow to an adjacent upper impeller. Specifically, diffusers generally have vanes that direct the fluid flow and build fluid pressure when transferring fluid to the adjacent upper impeller. The vanes of a diffuser include a lower pressure surface that receives fluid from an adjacently lower impeller and a higher pressure surface that directs the fluid to the adjacently upper impeller. After being moved through the impellers and diffusers of the pump, the fluid exits the pump, for example, to an uphole component in a downhole string.

During the rotation the impellers and the artificial lifting of the fluid through the pump, the components of the pump may be subjected to internal and/or external forces (e.g., rotational forces) that may impact operation of the pump. For example, such forces may act to loosen and/or fail couplings and/or orientations between components of the pump. Accordingly, such forces may impact the efficiency of the pump and/or may cause operational failure of the pump.

Some embodiments of the instant disclosure may relate to a downhole centrifugal pump including: impellers; a rotational shaft passing through the impellers to impart rotation to the impellers; diffusers having a body housing the impellers; bearings positioned within at least some of the diffusers, the bearings being positioned within a central portion of the body of each of the at least some of the diffusers with the rotational shaft extending through each of the bearings to support the rotational shaft during the rotation of the impellers; coupling pins positioned between and engaged with the bearings and the at least some of the diffusers, the coupling pins configured to at least partially secure each of the bearings to one of the at least some of the diffusers against a rotational force applied to the bearings from the rotation of the rotational shaft; and bushings positioned adjacent to the bearings, the bushings each configured to secure one of the bearings along the rotational shaft in the central portion of the body of the at least some of the diffusers.

Some embodiments of the instant disclosure may relate to a centrifugal pump including: impellers; a rotational shaft passing through the impellers to impart rotation to the impellers; diffusers having a body housing the impellers; bearings positioned within the diffusers to support the rotational shaft extending through each of the bearings during the rotation of the impellers; and coupling pins positioned between and engaged with the bearings and the diffusers, the coupling pins at least partially securing each of the bearings to one of the diffusers to resist a rotational force applied to the bearings.

Some embodiments of the instant disclosure may relate to a method of assembling a centrifugal pump, the method including: forming a stack of a plurality of diffusers; housing a plurality of impellers in the plurality of diffusers; extending a rotational shaft through the plurality of impellers to impart rotation to the plurality of impellers; supporting the rotational shaft with a plurality of bearings positioned within the plurality of diffusers; and positioning coupling pins between the plurality of bearings and the plurality of diffusers to at least partially secure each of the plurality of bearings to restrict, limit, and/or minimize relative rotation between the plurality of bearings and the plurality of diffusers.

As used herein, relational terms, such as “first,” “second,” “top,” “bottom,” etc., are generally used for clarity and convenience in understanding the disclosure and accompanying drawings and do not connote or depend on any specific preference, orientation, or order, except where the context clearly indicates otherwise.

As used herein, the term “and/or” means and includes any and all combinations of one or more of the associated listed items.

As used herein, the terms “vertical,” “lateral,” “radial,” “uphole,” and “downhole” refer to the orientations as depicted in the figures.

Embodiments of the instant disclosure are directed to exemplary fluid handling devices (e.g., pumps) that include one or more locking features. Such locking features may act to at least partially maintain (e.g., substantially maintain, substantially prevent movement of) the position of one or more components of the fluid handling device.

For example, a pump (e.g., a submersible pump, an electric submersible pump (ESP), a centrifugal pump, a multistage centrifugal pump, or any suitable pump, without limitation) may include or be coupled to a motor that drives a shaft coupled to impellers which are, in turn, rotationally coupled to diffusers. The impellers and diffusers are alternatingly situated around the shaft in a manner that causes fluid to flow from one impeller into a diffuser, and from the diffuser into another impeller as the shaft rotates. This process of fluid transfer from impeller to diffuser, and from diffuser to an adjacent upper impeller, repeats until the fluid travels from the downhole source to an upper destination.

In such a configuration, the diffusers and the components of the diffuser (e.g., diffuser bearings) are intended to remain substantially (e.g., entirely) stationary relative to the impellers and the shaft that rotate within the diffusers. The diffusers include one or more components that are positioned adjacent to (e.g., in contact with) one or more of the rotating shaft or the impellers. For example, one or more wear components (e.g., diffuser bearings or bushings) may provide a support surface for the rotating shaft as the shaft and impellers are driven by a motor.

In some embodiments, such diffuser bearings may be coupled to respective diffusers using an interference fit. For example, the diffusers may be heated to expand the material forming a housing or body of the diffuser bearings and the bearing may be installed. Once cooled, the diffusers may form a relatively tight fit to hold the bearings in place and minimize relative movement between the diffuser and an associated bearing.

However, during use, the couplings or connections between diffusers and the bearings may begin to degrade, enabling movement (e.g., rotational movement) of the bearing relative to the diffusers due to the rotation of the shaft. Such movement of the diffuser bearings may be relatively more common in relatively high heat applications where deformation (e.g., expansion) of the diffusers may loosen the couplings between the diffusers and the bearings to enable relative movement between the diffusers and the bearings. In additional embodiments, manufacturing defects, wear, damage, and/or other defects may cause the bearings to begin rotating within the diffusers.

In accordance with some embodiments of the disclosure, one or more locking features (e.g., mechanical stops) may be implemented in such pumps to at least partially ensure that one or more components of the diffusers remain in a stationary configuration where the one or more components do not substantially move relative to the rotating impellers and shaft, which are rotated by a motor to operate the pump. For example, the one or more components of the diffusers including such locking features may be components that are directly adjacent to or in direct contact with one or more of the spinning shaft or the impellers coupled to the shaft. The locking features may resist (e.g., minimize, substantially prevent) these components (e.g., wear components, such as the bearings or bushings that support the shaft within the pump) from beginning to rotate with the shaft due to the rotational forces (e.g., torque) associated with the spinning shaft.

As discussed below, the locking features may include one or more pins positioned to extend between diffusers and bearings housed by the diffusers in order to resist or minimize (e.g., substantially prevent) rotational movement of the diffuser bearings.

In some embodiments, an additional locking feature (e.g., a bushing housed by the diffuser via an interference fit) may be used to resist movement of the component (e.g., the bearing) in another direction of movement (e.g., movement in an axial direction along the shaft).

In some embodiments, the material of such a bushing may be selected to be similar to the material of the diffuser such that expansion and/or contraction of the diffuser and bushing may occur in a similar manner and/or rate due to heating and/or cooling during operation of the pump (e.g., by providing similar coefficients of thermal expansion (CTEs)). In such a configuration, the collective expansion and contraction of the bushing and the diffuser together may render it less likely that the bushing becomes loose in the body of the diffuser that houses the bushing.

Such locking features may be of particular use in applications where the pump is implemented in high heat environments and/or where the fluid being pumped includes a relatively high amount of fluid that is in an at least partially gaseous state. Such an environment may include a relatively higher amount of gas intermittently flowing or flowing in a substantially constant stream through the pump. In embodiments where a submersible pump is implemented, the pump may at least partially lack a separate lubrication or working fluid. Such a pump configuration at least partially relies on the process fluid being supplied through the pump to cool one or more components of the pump. As a result, in a relatively high gas environment where adequate lubrication may be intermittent or relatively less reliable, the components of the pump may be subjected to periods of relatively high heating that increase the probability of the components of the diffusers, such as the bearings, becoming dislodged and beginning to move. Embodiments of the instant disclosure including one or more locking features may enable the reduction of efficiency and/or failure of the pump due to movement of the components of the diffusers even in such high gas applications.

As discussed below, in some embodiments, the components of the diffusers may be coupled using a nonthreaded coupling device, such as, for example, a pin (e.g., protrusion) that is received in (e.g., slidingly received in) one or more complementary recesses defined between the body of the diffusers and one or more components of the diffusers. The use of such nonthreaded pins or protrusions may enable relatively simplified manufacture, assembly, and/or disassembly of the diffuser stack and associated componentry.

It is noted that the use of such locking features is discussed below primarily in relation to connections between the body of a diffuser and a diffuser bearing that is held by the body of the diffuser in order to interact with the shaft and/or impellers. However, in additional embodiments, such locking features may be used with any suitable components of the pump to resist relative movement between two or more components of the pump during use.

is a simplified side or elevation view of a downhole centrifugal pump system. Downhole centrifugal pump systems generally include at least a downhole structure housing a pump coupled to a motor. In some implementations, the downhole structure may include a plurality of pumps coupled to a plurality of motors. Depending on the use scenario, the downhole structure can be submerged in one or more fluid sources (e.g., oil or gas reservoir, aquifer, etc.) as needed. The plurality of pumps in the downhole structure may upwardly pump the fluid from the fluid source to receiving containers (e.g., tanks, vessels, etc.) at a higher elevation relative to the fluid source.

As shown in, the downhole centrifugal pump systemmay include one or more pumps, one or more gas handling devices, one or more protector devices, one or more motors, and one or more monitoring devices.

The pumpmay include a series of impellers and diffusers that are alternatingly coupled to each other. For example, and as shown in, the series of impellers and diffusers of the pumpmay include impellersrotationally coupled to associated diffusers. As above, in some implementations, the pumpmay be an electric submersible pump (ESP) configured to operate in high-volume wells and/or horizontal or highly deviated wells. For example, the pumpmay facilitate fluid production from 150 barrels per day (BPD) to 10,000 BPD and may range in size from 2 inches to more than 7 inches (5.08 to 17.78 centimeters) in diameter (e.g., 4 inches (10.16 centimeters)). This wide specification range allows the pumpto be adaptable to varying drilling conditions. Additionally, the pumpmay be abrasion-resistant and may enable the ability to handle solids in, for example, high sand production scenarios.

Turning back to, the gas handling devicemay be configured to mitigate against gas locking by reducing gas interference in the pump. In some implementations, the gas handling devicemay incorporate rotary and vortex gas separators that enhance pump efficiency by preventing free gas from entering the pumpin the first place. Operations executed by the gas handling devicemaximize fluid production by lowering pump drawdown and facilitating well uptime.

The protector devicemay be configured to ensure electrical and mechanical integrity of the motor. The motor(e.g., an electric motor, a hydraulic motor, an internal combustion engine, another type of prime mover, etc.) may operate the pumpby rotating one or more shafts that run through the length of pumpand that are coupled to impellers disposed in respective diffusers of the pump.

In some implementations, the protector devicemay act as an oil reservoir that facilitates the expansion capacity of the motor. The protector devicemay include a secure seal that keeps the motorrunning smoothly. Additionally, the protector devicemay further include one or more chambers adapted to prevent wellbore fluid contamination of the motorby creating a low-pressure boundary between the well fluid and the clean oil used to lubricate the motor. Moreover, the protector devicemay facilitate: torque transfer from the motor shaft to the gas handling deviceand/or pump intake shaft; reinforcement of the pump shaft; and adaptation of the downhole centrifugal pump systemto specific implementation considerations.

The motormay be configured to drive a shaft coupled to the pumpof the downhole centrifugal pump system. In some embodiments, the motormay be an electric submersible motor configured for variable-speed operations, high temperature tolerance, and deep well pumping. The motormay include one or more circuitry that allows 3-phase operations, 2-pole inductions, etc. The motormay be fabricated using corrosion resistant materials such as stainless steel.

The monitoring devicemay include software and/or firmware and other hardware that enables monitoring of the downhole centrifugal pump system. In some embodiments, the monitoring devicemay include one or more sensors (e.g., temperature sensors, pressure sensors, etc.) that capture a plurality of information during the operation of the downhole centrifugal pump system. This information may be transmitted via a wired and/or wireless channel to user interfaces that facilitate viewing of monitoring data associated with various operations of the downhole centrifugal pump systemand/or conditions in which the downhole centrifugal pump systemoperates.

is a cross-sectional view of a portion of a centrifugal pumphaving a longitudinal axis. As shown in, the centrifugal pumpmay include a stack of diffuserswith impellerspositioned in the stack of diffusers. For clarity, only two diffusersare shown (e.g., a middle diffuserand an end diffuser) positioned adjacent to (e.g., coupled with) a pump base. However, any number of diffusersmay be implemented with the diffusers, for example, with a repeated stack of middle diffusersextending to another end (e.g., an upper outlet) of the centrifugal pump.

As discussed above, the centrifugal pumpmay include or be coupled to a motor that drives (e.g., rotates) a shaft. The shaftis coupled to the impellersin order to rotate the impellerswithin the diffusers. Rotation of the impellerswithin the diffusersacts to drive fluid through the centrifugal pump. For example, in a downhole application, the impellersdrive the fluid from a lowermost or downhole portion of the centrifugal pumpwhere the fluid is supplied through an inlet to a fluid outlet at an uppermost or uphole portion of the centrifugal pump. In a downhole application, such a configuration may assist in moving the fluid up through the borehole to a location more proximate to a surface of the well.

Each of the diffusersmay include an outer portion (e.g., radial sidewall) that collectively defines an outer circumference of the stack of diffusers. The diffusersmay be received within an outer housingof the centrifugal pump.

Each of the diffusersand/or the pump basemay include one or more wear components (e.g., bearings) that interact with (e.g., support, provide a bearing surface for) the shaft(e.g., via a spacer sleeveof the shaft). For example, the shaftmay include one or more spacing sleevespositioned between the impellersthat are secured to the shaft. Similar spacing sleevesmay be implemented at the downhole portion of the shaftthat extends through the pump base.

One or more pinsmay be received within openingsdefined between a bodyof the diffusersand the bearings. Similarly, one or more pinsmay be received within an openingdefined between a portion of the pump base(e.g., an insert) and a bearinghoused by the pump base.

In some embodiments, the pinsmay be formed as a slotted pin to provide a biasing effect to the pinsas is shown in relative to the pinin the diffuser. For example, the pinsmay be compressed during assembly and then enabled to expand within the openingsto secure the pins. In some embodiments, the pinsmay be a solid cylindrical structure as is shown in relation to the pinin the pump base. In additional embodiments, the pins,may be selected to all be one type of structure (e.g., slotted, hollow, or solid) or may vary in construction as desired based on the components being secured and location of such components.

As depicted, the pins,may be a structure separate from the diffusers, the bearings, and/or the pump base. However, in additional embodiments, such as that discussed below, the pins,may be an integral protrusion of any suitable shape that is formed with the diffusers, the bearings, and/or the pump baseand may be received in (e.g., secured in) a complementary opening (e.g., recess, hole, depression) of an adjacent component of the centrifugal pump. Further, the pins,may be of any suitable shape, whether integrated or separate, in order to secure the bearings. For example, the pins,may be substantially cylindrical (e.g., as depicted), cuboid, or any other polygonal or suitable shape.

Where separable or removable pins,are implemented, each of the diffusersor the insertof the pump baseand a respective bearingmay include recesses to define the openings,. For example, axially extending recesses on each of the diffusersor the insertof the pump baseand the respective bearingmay collectively define the opening,for receiving the separable pin,.

In some embodiments, only one pin,or other protrusions may be implemented to secure each of the bearings. In additional embodiments, multiple pins,or other protrusions may be implemented to secure each of the bearings.

In some embodiments, an additional locking feature (e.g., retaining bushings) may be used to further secure the bearings. For example, while the bearingsare secured within the bodyof the diffusersor the insertof the pump basein radial directions and retained against rotational forces (e.g., torque) by the pins,, the retaining bushingsmay act to secure the bearingsin an axial direction (e.g., along longitudinal axis, along the shaft).

As depicted, the retaining bushingsmay be positioned within the bodyof the diffusersor the insertof the pump baseadjacent the bearingsto secure the bearingsagainst on one axial side while another portion of the bodyof the diffusersor the insertof the pump basesecures the bearingson the other axial side. In some embodiments, the retaining bushingsmay be positioned downhole of the bearings(e.g., as in the bodyof the diffuser) or uphole of the bearings(e.g., as in the insertof the pump base).

In some embodiments, the retaining bushingsmay be secured in the bodyof the diffusersor the insertof the pump basewith an interference fit similar to that discussed above where heating is used to expand the component that is to receive the retaining bushing.

As noted above, in some embodiments, the materials of the components of the pumpand one or more of the locking features may be selected to provide a similar expansion and/or contraction during heating and cooling periods within the pump. For example, the diffusersand/or pump baseand the retaining bushingsmay be selected to have a similar (e.g., substantially the same) coefficient of thermal expansion (CTE). In some embodiments, the diffusersand/or pump baseand the retaining bushingsmay each be formed from a metallic material (e.g., a ductile iron) in order to exhibit a similar CTE.

In some embodiments, the bearingsmay be formed from a differing material that is more suitable for the wear surfaces required to handle the rotational forces of the shaftand impellers. For example, the bearingsor wear surfaces of the bearingsmay comprise a metallic material (e.g., carbon steel, titanium or titanium alloys, tungsten or tungsten alloys, aluminum or aluminum alloys, or stainless steel, etc.), a carbide material (e.g., tungsten carbide, silicon carbide, etc.), a polycrystalline diamond (PCD) material, or any other suitable material.

is a perspective view of a diffuser of a centrifugal pump, which, in some embodiments, may be similar to the diffusersof the centrifugal pumpdiscussed above. It is noted that the inner portion of the insertof the pump basemay include similar structures for housing an associated bearing.

is a perspective view of a bearing of a centrifugal pump which, in some embodiments, may be similar to the bearingsof the centrifugal pumpdiscussed above.

As shown in, the bodyof the diffusersmay include a central annular portiondefining a recess for receiving an associated bearingand the shaft(). The annular portionmay be positioned at an innermost radial portion of the diffuser. The annular portionmay include a shelfat one axial end for abutting with the bearingwhen the bearingis positioned in the recess defined by the annular portion.

A sidewall of the bodyat the annular portionmay include a recess(e.g., an indentation) on an inner diameter (e.g., an interior diameter) of the bodyof the diffuserthat defines at least part of the openingfor receiving the pin. For example, the recessmay extend in an axial direction along the annular portionto receive approximately half of the pinwhen the pinis inserted between the bearingand the diffuser. As depicted, the recessmay extend to and stop at the shelfto provide a stop for one axial end of the pin,().

The bearingmay include a similar recessdefined in a sidewall of the bearingon an outer or exterior diameter or circumference of the bearing. For example, the recessmay extend in an axial direction along the bearingto receive approximately the other half of the pinwhen the pinis inserted between the bearingand the diffuser.