Vortex gas separator assembly and flexible shaft unit

Abstract

An electric submersible progressive cavity pump (ESPCP) system may include a vortex gas separator assembly (VGSA), comprising a head comprising holes for inserting pin for installation, grooves disposed at both ends for the pin installation, a stator having an internal bore, and a rotor disposed in the internal bore of the stator. The ESPCP system may comprise a flexible shaft unit (FSU) between the VGSA and the ESPCP.

Description

IS24.1145VORTEX GAS SEPARATOR ASSEMBLY AND FLEXIBLE SHAFT UNITCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims the priority benefit of Singapore Provisional Application No. 10202403007V filed September 27, 2024 and U.S. Provisional Application No. 63 / 816,387 filed June 2, 2025, the entirety of which is incorporated by reference herein and should be considered part of this specification.BACKGROUNDField

[0002] The low reliability of progressive cavity pumps (PCPs) in wells with a high gas volume factor is primarily due to the fact that, all other factors being equal, an increase in the pressure drop across the stages (stator pitch) of a PCP can lead to elastomer degradation and significant fluid leaks, which in turn decreases the pump's efficiency. The calculated pressure drop across the stages of a PCP depends on the compression fit between the rotor and stator before the pump is lowered into the well, as well as on the properties of the elastomer, the length of the stator pitch, and the characteristics of the gas-liquid mixture.

[0003] If the PCP is lowered to a deep well and low intake pressure is required, this results in a maximum pressure drop across the pump stages when operating on a homogeneous liquid. However, when a gas-liquid mixture with a high gas content (e.g., over 50% by volume) enters the pump, pulsations occur in the cavities between the rotor and stator, disrupting the compression fit between adjacent cavities. This leads to leaks in the decompression area of the pump, a decrease in pump flow, and, with prolonged operation in this mode, deformation of the elastomer element.

[0004] This application is also related to present advancements in the design of the Flexible Shaft Unit (FSU) for use in Electrical Submersible Progressive Cavity Pump (ESPCP) strings with a Vortex Gas Separator Assembly (VGSA).SUMMARY

[0005] An electric submersible progressive cavity pump (ESPCP) system may include a vortex gas separator assembly (VGSA), which itself may include a head with one or more holesIS24.1145 for inserting pins during installation, one or more grooves located at both ends of the VGSA shaft for installing those pins, a stator with an internal bore, and a rotor positioned within that bore.

[0006] The rotor may be designed to rotate clockwise within the stator’s internal bore to pump fluid through a series of progressive cavities. The rotor may include one or more inducers and one or more cavitation wheels. One or more bearings in the system may be configured to support clockwise shaft rotation. The ESPCP may include an electric motor that is coupled to a hollow rotor. The ESPCP may be part of a hydrocarbon extraction system. The hole in the VGSA head may be closed at both ends using two plugs, one on each end. The VGSA shaft may include one or more grooves extending from both ends. The grooves may be designed to allow installation of one or more pins into one or more couplings.

[0007] The grooves may also be designed to allow installation of one or more stencils into one or more couplings. The VGSA may be positioned beneath a flexible shaft unit (FSU). The system may be configured to allow fluid to flow first through one or more VGSA intake openings, then through the FSU, and finally through the ESPCP. The VGSA may be designed to operate at rotational speeds ranging from 200 rpm to 1000 rpm. A flexible shaft unit (FSU) may include a base with two sides, a sleeve, a lower bushing, and an upper bushing that includes one or more rings to allow radial movement. The FSU may also include one or more shredder rings and one or more shredder protectors, which may be installed on both sides of the base to shield the clearance between the lower or upper bushing and the sleeve.

[0008] The FSU may include a split housing composed of an upper housing, a center housing, and a lower housing. The base of the FSU may include one or more flow passages. The flow passages may be arranged in groups with spaces between each group. The base of the FSU may include three ribs. A method of pumping fluid in a borehole may include assembling a hollow rotor for an electric submersible progressive cavity pump (ESPCP), and installing the hollow rotor within the internal bore of a stator, where the rotor is configured to rotate clockwise to pump fluid through a series of progressive cavities. The method may further include pumping fluid through a vortex gas separator assembly (VGSA), then through a flexible shaft unit (FSU), and finally through the ESPCP.IS24.1145BRIEF DESCRIPTION OF THE FIGURES

[0009] 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.

[0010] FIG. 1 is a diagram illustrating a vortex gas separator assembly for progressive cavity pump, according to one or more examples of the disclosure.

[0011] FIG. 2 is a graph illustrating parametric curves (permissible gas content at the intake at residual gas content - 25% and 50%) of gas separators: Qint.nom.= 500 m3 / day [4.2Hz(200rpm) - 16Hz( 1 OOOrpm), highly viscous fluid 200cP, according to one or more examples of the disclosure.

[0012] FIG. 3 is a diagram illustrating grooves placed at both ends of a shaft, according to one or more examples of the disclosure.

[0013] FIG. 4 is a diagram illustrating a technological through hole at a head of the vortex gas separator assembly, according to one or more examples of the disclosure.

[0014] Figure 5 shows a bushing design according to some embodiments.

[0015] Figure 6 shows a split housing design.

[0016] Figure 7 shows an FSU base according to some embodiments.

[0017] Figure 8 shows another view of an FSU base according to some embodiments.

[0018] Figures 9A and 9B show a base with flow slots for FSU design according to some embodiments.

[0019] Figures 10A and 10B show another view of a base with flow slots for FSU design according to some embodiments.

[0020] Figure 11 shows an FSU assembly overview according to some embodiments.

[0021] Figure 12 shows an FSU assembly overview according to some embodiments.DETAILED DESCRIPTION

[0022] 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 theIS24.1145 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.

[0023] Embodiments of this disclosure relate to a device designed to reduce the volume of gas at the inlet of a progressive cavity pump (PCP) wherein the device is a vortex gas separator assembly (VGSA), which differs from other VGSAs in at least the following ways, as illustrated in FIG. 1 : a. Rotor components may be adapted for clockwise shaft rotation (including inducers and cavitation wheels); b. Bearings may be designed for clockwise shaft rotation; c. The shaft may have special grooves on both ends which are used for installing pins; and d. The head of the device may have special holes for pin installation.

[0024] The VGSA 100 of Fig. 1 may comprise a head 102, a coupling 104, a bearing housing 106, impeller VGSA 108, bearing support 110, housing 112, inducer gas separator 114, shaft 116, inducer spiral 118, and base 120. An ESPCP may be a hybrid pumping system that combines the high-lift capabilities of an electric submersible pump (ESP) with the viscous-fluid handling of a progressive cavity pump (PCP). It is designed to operate in wells with high gas content, sand, or heavy oil. The ESPCP may comprise an electric motor, a rotor-stator assembly, and associated components (e.g., shaft, bushings, separators) arranged in a downhole string. The rotor rotates inside the stator to form cavities that move fluid upward. An electric motor in an ESPCP system may be a downhole power source that converts electrical energy into mechanical rotation to drive the rotor. It may beIS24.1145 designed to operate under high temperature and pressure conditions and is typically coupled directly to the rotor via a shaft.

[0025]

[0026] The VGSA 100 may be a downhole device configured to separate gas from liquid before the fluid enters the pump, thereby reducing gas interference and improving pump efficiency. Structurally, the VGSA may include a head, a shaft with grooves at both ends, impellers or inducers, and internal flow paths that induce a vortex effect to facilitate phase separation. The VGSA may be positioned beneath the flexible shaft unit (FSU) in the ESPCP string.

[0027] The head of the VGSA may be a structural component that serves as a mounting and alignment interface for connecting the VGSA to adjacent components. It may include one or more machined holes designed to receive pins that secure the VGSA shaft to couplings or other parts of the assembly. These holes may be closed from both ends with plugs to prevent fluid ingress.

[0028] In various embodiments in this application, a VGSA shaft may include one or more grooves machined into both ends, which are configured to receive pins or stencils for mechanical coupling. These grooves may facilitate secure installation and alignment of the shaft with couplings, helping to maintain rotational integrity during operation. Stencils may refer to alignment or locking components used in conjunction with pins and grooves to secure couplings to the VGSA shaft. They may help ensure precise positioning and rotational stability during operation.

[0029] The stator may be a stationary component of the progressive cavity pump, and may be made of steel lined with elastomer. It may have a helical internal bore that matches the geometry of the rotor, allowing the formation of progressive cavities as the rotor turns. The stator’s bore may be useful for fluid displacement and sealing performance.

[0030] A rotor may be a helical metal shaft that is positioned within the internal bore of the stator. As it rotates, it forms a series of cavities that progressively move fluid upward through the pump. The rotor may be designed for clockwise rotation (or counterclockwiseIS24.1145 rotation) and may include features such as inducers or cavitation wheels to enhance fluid handling.

[0031] Pins may be cylindrical mechanical fasteners used to secure and align components within the ESPCP system. In this context, they may be inserted through holes in the VGSA head and into grooves on the shaft to lock the VGSA in place. These pins may be made of corrosion-resistant metal (or other material) and designed to withstand downhole mechanical stresses.

[0032] An inducer gas separator 114 may be a specialized component within a vortex gas separator assembly (VGSA) designed to initiate and enhance the separation of gas from liquid in multiphase flow environments. It helps reduce gas ingestion into the pump by creating a controlled vortex or helical flow pattern that promotes centrifugal separation of gas from liquid. The inducer gas separator may include rotating intake elements, stationary vortex-inducing geometries, and internal liquid reservoirs that stabilize flow and mitigate gas slugs.

[0033] An inducer spiral 118 may be a helical or spiral-shaped component integrated into the shaft or intake section of a VGSA or ESPCP system. It may be designed to impart rotational motion to incoming fluid, thereby enhancing the vortex effect and improving phase separation between gas and liquid. The inducer spiral may be machined or affixed to the shaft and configured to direct fluid flow in a spiral path, increasing residence time and centrifugal force within the separator. This spiral geometry contributes to smoother fluid intake and reduced turbulence, which are critical for maintaining pump efficiency and preventing gas lock.

[0034] The use of the new Vortex Gas Separator with electrical submersible PCP (ESPCP) may provide a decrease of the gas volume at the intake of the PCP at operating speeds of up to 1000 rpm in viscous fluids with viscosities up to 200 cP.

[0035] Tests were conducted across a range of rotational speeds from 200 to 1000 rpm in fluid with viscosity of 200 cP, simulating the operating conditions of the wells with flow rates between 25 and 100 m3 / day. The pressure and temperature at the gas separator inlet were maintained constant throughout the tests. The results of the tests are shown in FIG. 2.IS24.1145

[0036] The VGSA 300 of FIG. 3 may comprise shipping cap 302, pipe PVC 304, screw 306, pins 310, head VGSA 312, coupling 314, and shaft grooves 326. In one embodiment, the gas separator, may have special grooves from both ends on its shaft to install the pins into the couplings, as shown in FIG. 3. The VGSA of FIG. 3 may comprise hex nut 318, shaft 316, shipping cap 320, screw hex 322, shaft grooves 326, and spacer block 324. Coupling 314 may be a mechanical connector used to join the VGSA shaft to adjacent components in the ESPCP system, such as the flexible shaft unit (FSU) or the rotor assembly. It may serve to transmit torque and maintain alignment between rotating parts while allowing for secure installation and disassembly. The coupling may be designed to interface with grooves on the shaft and receive pins for locking the connection in place. It may be made of high-strength, corrosion-resistant metal and engineered to withstand downhole pressure, temperature, and rotational forces.

[0037] Shaft 316 may be the central rotating element of the VGSA, responsible for transmitting torque from the motor to the inducer and other rotating components. It may be machined from high-strength metal and designed to accommodate grooves, pins, and other features that enable secure coupling and efficient fluid handling.

[0038] Hex nut 318 may be a six-sided threaded fastener used to secure components of the VGSA assembly, such as the shaft or coupling. It may be tightened onto a corresponding bolt or threaded shaft to lock parts in place and prevent loosening due to vibration or rotation during pump operation.

[0039] Shipping cap 320 may be a protective cover placed over the ends of the VGSA shaft or other exposed components during transport and handling. It may prevent contamination, physical damage, or deformation before installation in the well.

[0040] Screw hex 322 may be a hexagonal-headed screw used to fasten components such as the shipping cap, spacer block, or coupling. It may be designed for easy installation and removal using standard hex tools, and may be made of corrosion-resistant material suitable for downhole environments.

[0041] Spacer block 324 may be a structural element used to maintain a fixed distance between components in the VGSA assembly, such as between the shaft and coupling orIS24.1145 between bushings. It may help distribute mechanical loads and ensure consistent alignment during operation.

[0042] Shaft grooves 326 may be recessed channels machined into both ends of the VGSA shaft. These grooves may be designed to receive pins or stencils that secure the shaft to couplings or other components, ensuring proper alignment and rotational stability.

[0043] The head of the VGSA 400 of FIG. 4 may comprise a plug socket 402 and a pin 404. Further, as seen in FIG. 4, the head may comprise a through hole to insert the pin(s) and stencil(s) the coupling to fix the pin(s) in its / their position. The through hole may be closed from both ends with plugs to prevent the well fluid entry through.

[0044] This disclosure is also directed to solving other problems related to traditional ESPCP strings. Traditional ESPCP strings, lacking VGSA integration beneath the FSU, allow well fluid to enter the string through multiple openings on the FSU housing's side wall, subsequently moving upwards into the progressive cavity pump (PCP) via the rotation of the helical rotor. The PCP may be engineered to manage fluids with high viscosity and sand concentration, tolerating a certain degree of gas content. However, excessive gas content leads to lubrication loss within the PCP cavity, resulting in dry friction between the PCP rotor and stator. This condition induces localized heat spots, causing deformation and degradation of the rubber in the PCP stator.

[0045] To address operation within gassy wells, the VGSA has been proposed for connection beneath the FSU to separate gas from the well fluid. This novel ESPCP and VGSA configuration is disclosed herein. With VGSA integration, the FSU housing holes do not exist, directing fluid to enter through VGSA intake openings, progressing through the FSU to the PCP. Sands and solids also enter through VGSA intake and proceed into the FSU.

[0046] The traditional FSU design, intended for operation without VGSA, is ill-equipped to transport sands through its internal structures, posing a high risk of clogging within the tight clearances of the FSU bushing supports. Furthermore, the eccentric shaft movement from the PCP rotor exacerbates wear on the FSU base bushings. This disclosure introduces a redesigned FSU that addresses sand accumulation and bushing damage issues, ensuring compatibility with the VGSA.IS24.1145

[0047] A flexible shaft may be a torque-transmitting component that accommodates bending and eccentric motion between the motor and rotor. It may be designed to reduce side loads and wear on bushings by flexing under dynamic conditions.

[0048] The bushing design in FIG. 5 may comprise shredder 502, spacer 504, base 506, shaft 508, shredder 510, lower bushing 512, upper bushing 514, and square rings 516 (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 square rings).

[0049] Shredder 502 and shredder 510 may be components (e.g., ring-like) positioned on either side of the FSU base to help break up or deflect sand and solid particles. These shredders may prevent abrasive materials from accumulating near the bushings and sleeve, reducing wear and extending the life of the assembly.

[0050] Spacer 504 may be a structural element used to maintain a fixed distance between components within the FSU, such as between the bushings and the shaft or sleeve. It may help distribute mechanical loads evenly and ensure proper alignment during operation.

[0051] Base 506 may be a part of the FSU assembly that supports the shaft, bushings, and other internal components. It may include flow passages, ribs, or slots designed to manage fluid movement and prevent sand accumulation.

[0052] Shaft 508 may be the rotating element within the FSU that transmits torque from the motor to the rotor. It may be designed to accommodate bending and eccentric motion while maintaining alignment with the bushings and couplings.

[0053] Lower bushing 512 may be a wear-resistant sleeve located at the bottom of the FSU base, designed to support the shaft and absorb side loads. It may be made thicker than traditional bushings to improve impact resistance and reduce the risk of cracking under stress.

[0054] Upper bushing 514 may be a mount-style bushing located at the top of the FSU base, designed to allow for radial movement of the shaft. It may include square rings that provide compliance and flexibility, helping to mitigate side loads caused by shaft deflection.

[0055] Square rings 516 may be elastomeric or polymer rings or metallic rings integrated into the upper bushing to allow controlled radial movement of the shaft. These rings mayIS24.1145 help absorb mechanical stress and reduce wear by providing a flexible interface between the shaft and bushing.

[0056] The bushing design in this disclosure provides several improvements. The lower bushing 512 of the FSU base may be enhanced with increased thickness to bolster side load capacity, improving impact and crack resistance.

[0057] Applied to the upper bushing 514 (e.g., mount bushing), a compliant mount design with square rings 516 (e.g., 4 square rings) may allow for radial movement, mitigating side load forces from the flexible shaft during bending deflection due to eccentric movement.

[0058] Shedder Protection: Shedder 502 rings and protectors may be installed on both sides of the base to shield the clearance between the bushing and sleeve, reducing the likelihood of sand and solids accumulation that could cause abrasive wear.

[0059] This application also discloses a constant flow velocity design. The split housing design of FIG. 6 may comprise an upper housing 602, a center housing 604, and a lower housing 606. A split housing may be a multi-section casing design (e.g., upper, center, and lower housing) used in the FSU to simplify assembly and improve fluid flow. It may minimize cross-sectional changes to maintain consistent axial velocity.

[0060]

[0061] To maintain consistent axial velocity, this split housing design minimizes cross- sectional area variations, ensuring stable and efficient fluid flow.

[0062] The base of FIG. 7 may comprise one or more flow passages 702. The base of FIG.8 may also comprise one or more flow passages 802 (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20). The flow passages 802 may be arranged in groups of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 with or without a space between each group. In some embodiments, certain groups may have a different amount of passages. The FSU base may be modified with extra slots of uniform size and reduced settling area to enhance sand handling and minimize clogging risks.

[0063] In some embodiments, the base may have flow slots for the FSU. The base of FIG.9 may comprise body 902, and flow passage 904.IS24.1145

[0064] Certain embodiments may prevent sand accumulation through a three-rib structure (or two-rib, four-rib, five-rib, six-rib, seven-rib, eight-rib, or nine-rib structure), maintaining optimal flow conditions and ensuring uninterrupted operation.

[0065] The FSU design of FIG. 10 may comprise flow passages / ribs 1002 (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 flow passages). Flow passages may be channels or openings integrated into the base or housing of the flexible shaft unit (FSU) to guide fluid through the assembly. These passages may be designed to maintain consistent axial velocity, reduce turbulence, and prevent sand or solid accumulation.They may vary in number and arrangement, sometimes grouped with spacing between them to optimize flow distribution and minimize clogging. By directing fluid efficiently, flow passages help maintain pump performance and reduce wear on internal components. Ribs may be raised structural features within the base or housing of the FSU that help support the internal geometry and guide fluid flow. They may also serve to prevent sand buildup by disrupting settling zones and maintaining movement through the flow passages. Ribs may be arranged in configurations such as three-rib, four-rib, or more, depending on the design. Their presence contributes to mechanical strength and helps ensure uninterrupted operation in sandy or viscous fluid environments.

[0066] The assembly overview of FIG. 11 may comprise a flex shaft 1102, coupling 1104, shaft 1106, base 1 108, lower housing 11 12.

[0067] The assembly overview of FIG. 12 may comprise a body 1202, coupling 1206, VGSA shaft 1208, VGSA head 1210, and shaft 1212.

[0068] The novel and inventive assembly allows for several benefits. The Center Spacer may cause increased flow uniformity by preventing sudden area changes and pressure drops. The Unified Coupling Design may eliminate the need for additional spacers, simplifying installation and dismantling for easier rework.

[0069] The Extended Shedder Bushing Design may provide extra protection to friction pairs under upthrust conditions. High-Strength Shaft Material may be utilized to withstand high torque demands.IS24.1145

[0070] The Lower sideload design may mitigate the issue of increased side load on the top bushing. The newly optimized design may incorporate a smaller diameter shaft, effectively reducing the side load significantly. This reduction is further enhanced by adjustments in the bushing span, contributing to an additional decrease in load. Consequently, this design modification alleviates the stress exerted on the bushing, enhancing the system's reliability.

[0071] A hollow rotor may be a rotor with an internal cavity or bore, which can reduce weight, allow fluid passage, or accommodate instrumentation. In ESPCP systems, it may be used to optimize torque transmission and reduce mechanical stress.

[0072] A hydrocarbon extraction system may refer to the complete set of equipment and processes used to recover oil and gas from a well. This may include the ESPCP system, surface facilities, separators, and flowlines configured to handle multiphase fluids and deliver hydrocarbons to processing or storage.

[0073] A sleeve in the FSU may be a cylindrical casing that surrounds the shaft and bushings, providing structural support and protection. It may also serve as a flow conduit or housing for internal components.

[0074] Flow slots may be elongated openings or channels in the FSU base that allow fluid and solids to pass through. They may be designed to reduce settling and clogging by maintaining consistent flow velocity.

[0075] A center spacer may be a structural element positioned between components in the ESPCP or FSU assembly to maintain uniform spacing and promote even fluid distribution. It may help prevent pressure drops and turbulence.

[0076] A unified coupling design may refer to a simplified coupling configuration that integrates multiple connection functions into a single unit. This may reduce the need for separate spacers or adapters, streamlining installation and rework.

[0077] An extended shedder bushing design may include additional protective features such as longer shredder rings or enhanced geometry to shield friction pairs from solids under upthrust conditions. It may improve durability and reduce abrasive wear.IS24.1145

[0078] High-strength shaft material may refer to alloys or composites selected for their ability to withstand high torque, bending, and corrosive environments. These materials may include stainless steel, Inconel, or other engineered metals used in downhole applications.

[0079] A lower sideload design may be an optimized configuration that reduces lateral forces on the upper bushing by adjusting shaft diameter and bushing span. This may improve reliability and reduce wear in the FSU.

[0080] The foregoing description, for purposes of explanation, used specific nomenclature to provide a thorough understanding of the disclosure. However, it will be apparent to one skilled in the art that the specific details are not required in order to practice the systems and methods described herein. The foregoing descriptions of specific examples are presented for purposes of illustration and description. They are not intended to be exhaustive of or to limit this disclosure to the precise forms described. Obviously, many modifications and variations are possible in view of the above teachings. The examples are shown and described in order to best explain the principles of this disclosure and practical applications, to thereby enable others skilled in the art to best utilize this disclosure and various examples with various modifications as are suited to the particular use contemplated. It is intended that the scope of this disclosure be defined by the claims and their equivalents below.

[0081] 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.IS24.1145

[0082] 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.

[0083] 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.

Claims

IS24.1145CLAIMSWhat is claimed is:

1. An electric submersible progressive cavity pump (ESPCP) system comprising: a vortex gas separator assembly (VGSA), comprising: a head comprising one or more holes for inserting one or more pins for installation; one or more grooves disposed at both ends of a VGSA shaft for the installation of the one or more pins; a stator having an internal bore; and a rotor disposed in the internal bore of the stator.

2. The ESPCP system of claim 1, wherein the rotor is configured for clockwise shaft rotation within the internal bore to pump fluid via a plurality of progressive cavities.

3. The ESPCP system of claim 1, wherein the rotor may comprise one or more inducers and one or more cavitation wheels.

4. The ESPCP system of claim 1, wherein one or more bearings are configured for clockwise shaft rotation.

5. The ESPCP system of claim 1, wherein the ESPCP comprises an electric motor coupled to the hollow rotor.

6. The ESPCP system of claim 1, comprising a hydrocarbon extraction system having the ESPCP.

7. The ESPCP system of claim 1, wherein the hole is closed from two ends with two plugs, one plug on each end.

8. The ESPCP system of claim 1, wherein the VGSA comprises one or more grooves running from both ends on its shaftIS24.11459. The ESPCP system of claim 1, wherein the one or more grooves are configured for the install of the one or more pins into one or more couplings.

10. The ESPCP system of claim 1, wherein the one or more grooves are configured for the install of the one or more stencils into one or more couplings.

11. The ESPCP system of claim 1, wherein the VGSA is located beneath a flexible shaft unit (FSU).

12. The ESPCP system of claim 1, wherein the ESPCP system is configured to allow fluid to flow through one or more VGSA intake openings, then through the FSU, and then through the ESPCP.

13. The ESPCP system of claim 1, wherein the VGSA is configured for a rotational speed of 200 rpm to 1000 rpm.

14. A flexible shaft unit (FSU), the FSU comprising:A base, the base comprising two sides; a sleeve; a lower bushing; an upper bushing, the upper bushing comprising one or more rings to allow for radial movement; one or more shredder rings; one or more shredder protectors, wherein the one or more shredder rings and one or more shredder protectors are configured to be installed on both sides of the base to shield clearance between the lower bushing or the upper bushing and the sleeve;IS24.114515. The FSU of claim 14, wherein the FSU comprises a split housing with a upper housing, center housing, and lower housing.

16. The FSU of claim 14, wherein the base comprises one or more flow passages.

17. The FSU of claim 16, wherein the one or more flow passages are configured in groups with a space between each group.

18. The FSU of claim 14, wherein the base comprises three ribs.

19. A method of pumping fluid in a borehole, the method comprising: assembling a hollow rotor of an electric submersible progressive cavity pump (ESPCP); and installing the hollow rotor within an internal bore of a stator of the ESPCP, wherein the hollow rotor is configured for clockwise shaft rotation within the internal bore to pump a fluid via a plurality of progressive cavities.

20. The method of claim 19, further comprising pumping fluid through a VGSA, then through a flexible shaft unit (FSU), then the ESPCP.

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