Well Bottom Gas Separator Assembly, Method for Lifting Liquid in a Well Borehole, and Method for Assembling an Electric Submersible Pump Assembly

Abstract

A downhole gas separator assembly, a method for lifting liquid in a wellbore, and a method for assembling an electric submersible pump assembly. A downhole gas separator assembly. The gas separator comprises a drive shaft; a first fluid mover mechanically coupled to the drive shaft having a fluid inlet and a fluid outlet; a fluid reservoir arranged concentrically around the drive shaft and located downstream of the first fluid mover, wherein an inner surface of the fluid reservoir and an outer surface of the drive shaft define a first annular space that is fluidically coupled to the fluid outlet of the first fluid mover;a second fluid mover having a fluid inlet and a fluid outlet, wherein the second fluid mover is located downstream of the fluid reservoir, and wherein the fluid inlet of the second fluid mover is fluidically coupled to the first annular space; and a separator of the gas flow path and the liquid flow path having a gas phase discharge orifice open to an exterior of the assembly and a liquid phase discharge orifice.

Description

1 / 38 “WELLBOTTOM GAS SEPARATOR ASSEMBLY, METHOD FOR LIFTING LIQUID IN A WELLBORE AND METHOD FOR ASSEMBLING AN ELECTRIC SUBMERSIBLE PUMP ASSEMBLY” Fundamentals

[0001] Electric submersible pumps (hereinafter “ESP” or “ESPs”) can be used to lift production fluid in a wellbore. Specifically, ESPs can be used to pump production fluid to the surface in wells with low reservoir pressure. ESPs can be important in wells having low bottomhole pressure or for use with production fluids with a low gas / oil ratio, a low slug point, a high water cut, and / or a low API gravity. Additionally, ESPs can also be used in any production operation to increase the flow rate of production fluid to a target flow rate.

[0002] Generally, an ESP comprises an electric motor, a sealing section, a pump inlet, and one or more pumps (e.g., a centrifugal pump). These components may all be connected to a series of shafts. For example, the pump shaft may be coupled to the motor shaft via the inlet and sealing shafts. An electrical power cable supplies electrical power to the electric motor from the surface. The electric motor provides mechanical torque to the shafts, which provide mechanical power to the pump. Fluids, for example, reservoir fluids, may enter the wellbore where they may flow past the exterior of the motor to the pump inlet. These fluids may then be produced by being pumped to the surface within the production tubing via the pump, which discharges the reservoir fluids into the production tubing.

[0003] Reservoir fluids entering the ESP may sometimes comprise a gas fraction. These gases may flow upwards through the liquid portion of the reservoir fluid into the pump. The gases may even separate from other fluids when the pump is in operation. If a large volume of gas enters the ESP, or if a sufficient volume of gas accumulates on the suction side of the ESP, the gas may interfere with the operation of the ESP and potentially prevent reservoir fluid from entering. This phenomenon is sometimes referred to as a “gas lock” because the ESP is unable to operate. Petition 870260045189, dated 05 / 13 / 2026, p. 9 / 72 2 / 38 properly due to gas buildup inside the ESP. Brief description of the drawings

[0004] For a fuller understanding of the present disclosure, reference is now made to the brief description, taken together with the accompanying drawings, and the detailed description, where similar reference numbers represent similar parts.

[0005] FIG. 1 is an illustration of an electric submersible pump (ESP) assembly according to an embodiment of the disclosure.

[0006] FIG. 2 is an illustration of a gas separator assembly according to an embodiment of the disclosure.

[0007] FIG. 3 is an illustration of another gas separator assembly according to an embodiment of the disclosure.

[0008] FIG. 4 is an illustration of an annular space in the interior of the gas separator assembly according to an embodiment of the disclosure.

[0009] FIG. 5A is an illustration of an annular space corresponding to the annular space within the gas separator assembly of FIG. 4.

[0010] FIG. 5B is an illustration of a cross-sectional area of ​​the annular space of FIG. 5A.

[0011] FIG. 6A is an illustration of another annular space and a spider bearing in an interior of the gas separator assembly according to an embodiment of the disclosure.

[0012] FIG. 6B is an illustration of a cross-section of the spider bearing according to an embodiment of the disclosure.

[0013] FIG. 6C is a further illustration of another annular space and a plurality of spider bearings in an interior of the gas separator assembly according to an embodiment of the disclosure.

[0014] FIG. 7A and FIG. 7B are a flowchart of a method according to a modality of disclosure.

[0015] FIG. 8A and FIG. 8B are a flowchart of another method according to a modality of disclosure.

[0016] FIG. 9 is an illustration of a tandem gas separator assembly according to Petition 870260045189, dated 05 / 13 / 2026, p. 10 / 72 3 / 38 with a method of disclosure. Detailed description

[0017] It should be understood from the outset that, although illustrative implementations of one or more embodiments are illustrated below, the disclosed systems and methods may be implemented using any number of techniques, whether currently known or not yet existing. The disclosure shall in no way be limited to the illustrative implementations, drawings and techniques illustrated below, but may be modified within the scope of the appended claims, along with their full scope of equivalents.

[0018] As used in this document, the guidance terms “upstream,” “downstream,” “upward,” “downward,” “up-hole,” and “down-hole” are defined in relation to the direction of well fluid flow in the well casing. “Upstream” is directed against the direction of well fluid flow, toward the source of well fluid (e.g., toward perforations in the well casing through which hydrocarbons flow out of a subsurface formation and into the casing). “Downstream” is directed in the direction of well fluid flow, away from the source of well fluid. “Downward” and “down-hole” are directed against the direction of well fluid flow, toward the source of well fluid. “Upward” and “up-hole” are directed in the direction of well fluid flow, away from the source of well fluid."Fluidically coupled" means that two or more components have internal communicating passages through which fluid, if present, can flow. A first component and a second component can be "fluidically coupled" through a third component located between the first and second components if the first component has internal passage(s) that communicate(s) with internal passage(s) of the third component, and if the same internal passage(s) of the third component communicate(s) with internal passage(s) of the second component.

[0019] Gas entering a centrifugal pump in an electric submersible pump (ESP) assembly can cause various difficulties for the centrifugal pump. In an extreme case, the pump can become blocked by gas and become unable to pump. Petition 870260045189, dated 05 / 13 / 2026, page 11 / 72 4 / 38 fluid. In less extreme cases, the pump may experience detrimental operating conditions when transiently passing through a gas slug. When in operation, the centrifugal pump rotates at a high speed (e.g., around 3,600 RPM) and relies on the continuous flow of liquid from the reservoir to cool and lubricate its bearing surfaces. When this continuous flow of liquid from the reservoir is interrupted, even for a brief period of seconds, the centrifugal pump bearings can rapidly overheat and suffer significant wear, shortening the operational life of the centrifugal pump, thus increasing operating costs due to replacement and / or repair of the centrifugal pump. The downtime involved in repairing or replacing the centrifugal pump can also undesirably interrupt well production.In some operating environments, for example, in some horizontal wellbores, gas slugs that persist for at least 10 seconds are repeatedly experienced. Some gas slugs may persist for up to 30 seconds or more. This disclosure prescribes a novel gas separator assembly that mitigates the effects of gas slugs.

[0020] A gas separator assembly may comprise an inlet that feeds fluid from the reservoir to a first fluid mover (e.g., a multi-stage centrifugal pump or a rotary auger) and the first fluid mover drives the fluid from the reservoir through a second fluid mover and the second fluid mover (e.g., a paddle wheel, a stationary auger, a vortex inducer) imparts a rotary motion to the reservoir fluid. The rotating reservoir fluid flows from the second fluid mover to a separation chamber. The rotation of the reservoir fluid in the separation chamber tends to separate the gaseous phase fluid from the liquid phase fluid.Due to the rotation of the reservoir fluid, the relatively lower density gaseous phase fluid tends to concentrate near a centerline axis of the gas separator assembly (e.g., near a drive shaft of the gas separator assembly), and the relatively higher density liquid phase fluid tends to concentrate near an inner wall of a housing or separation chamber of the gas separator assembly. The fluid near the centerline axis enters a gaseous phase discharge of the gas separator assembly and exits the gas separator assembly into an annular space formed between the wellbore and the... Petition 870260045189, dated 05 / 13 / 2026, p. 12 / 72 5 / 38 outside the ESP assembly; the fluid near the inner wall enters a liquid phase discharge of the gas separator assembly and is directed downstream to another stage of the gas separator assembly or to an inlet of the centrifugal pump assembly. In this way, it can be said that the reservoir fluid that is fed downstream of the inlet of the centrifugal pump assembly is a liquid-enriched reservoir fluid or a liquid-enriched fraction of the reservoir fluid.

[0021] In the event that a large gas slug reaches the ESP assembly, however, a conventional gas separator assembly can quickly fill with gas. In this circumstance, there is no liquid phase fraction to separate and forward as a liquid-enriched fraction of the reservoir fluid. When the large gas slug first reaches the gas separator assembly, for a short period of time, the liquid phase fluid retained within the fluid mover passages can mix with the slug gas, and a mixture of gas phase fluid and liquid phase fluid can be briefly supplied by the gas separator assembly to the centrifugal pump assembly.This mixture of gas-phase and liquid-phase fluid can provide lubrication to the bearing surfaces of the centrifugal pump assembly, provide heat transfer away from the bearing surfaces of the centrifugal pump assembly, and prevent the centrifugal pump assembly from entering a gas slug condition. However, the fluid mover passages (e.g., impeller vane channels and diffusers) are limited in volume, and the retained liquid-phase fluid is rapidly depleted in the presence of a large gas slug.This disclosure outlines the creation of additional internal volumes within the gas separator assembly between fluid mover stages (e.g., between centrifugal pump stages) that operate as liquid-phase fluid reservoirs, which can extend the transition time from normal operation to a condition where the gas separator assembly is completely filled with gas and does not supply liquid-phase fluid to the centrifugal pump assembly inlet.

[0022] Returning now to FIG. 1, a well site environment 100, according to one or more aspects of the disclosure, is described. The well site environment 100 comprises a wellbore 102 that is at least partially lined with casing 104. As depicted in FIG. 1, the wellbore 102 has a deviated or horizontal portion. Petition 870260045189, dated 05 / 13 / 2026, page 13 / 72 6 / 38 106, but the electric submersible pump (ESP) assembly 132 described in this document can be used in a wellbore 102 that does not have a deviated or horizontal portion 106. The well site environment 100 can be in a coastal location or an offshore location. The ESP assembly 132 in one embodiment comprises a sensor package 120, an electric motor 122, a sealing unit 124, a gas separator assembly 126, and a centrifugal pump assembly 128. The centrifugal pump assembly can couple to a production pipeline 134 via a connector 130. An electrical cable 135 can attach to the electric motor 122 and extend to the surface 158 to connect to an electrical power source. The gas separator assembly 126 comprises inlet ports 136 and gas phase discharge ports 138.Casing 104 and / or wellbore 102 may have boreholes 140 that allow reservoir fluid 142 to pass from the underground formation through the boreholes 140 and into wellbore 102. In one embodiment, a distance between inlet boreholes 136 and gas discharge boreholes 138 is less than 500 feet and at least 4 feet, at least 6 feet, at least 8 feet, at least 10 feet, at least 12 feet, at least 14 feet, at least 16 feet, at least 18 feet, at least 20 feet, at least 22 feet, at least 24 feet, at least 26 feet, at least 28 feet, at least 30 feet, at least 32 feet, at least 35 feet, at least 40 feet, at least 45 feet, at least 50 feet, at least 60 feet, at least less than 70 feet, at least 80 feet, at least 90 feet, at least 100 feet, at least 120 feet, or at least 140 feet.

[0023] Reservoir fluid 142 can flow uphole toward the ESP assembly 132 and into the inlet holes 136. Reservoir fluid 142 may comprise a liquid-phase fluid. Reservoir fluid 142 may comprise a gas-phase fluid mixed with a liquid-phase fluid. Reservoir fluid 142 may comprise only a gas-phase fluid (e.g., simply gas). Over time, the gas-to-fluid ratio of reservoir fluid 142 may change drastically. For example, in the horizontal portion 106, wellbore gas may accumulate at high points on the roof of the wellbore 102 and after accumulating sufficiently may “expel” from these high points and flow downstream to the ESP assembly 132 as what is commonly referred to as a gas slurry. Thus, immediately before Petition 870260045189, dated 05 / 13 / 2026, page 14 / 72 7 / 38 When a gas slurry reaches ESP 132 assembly, the gas-fluid ratio of reservoir fluid 142 may be very low (e.g., reservoir fluid 142 in ESP 132 assembly is primarily liquid-phase fluid); when the gas slurry reaches ESP 132 assembly, the gas-fluid ratio is very high (e.g., reservoir fluid 142 in ESP 132 assembly is entirely or almost entirely gas-phase fluid); and after the gas slurry has passed through ESP 132 assembly, the gas-fluid ratio may again be very low (e.g., reservoir fluid 142 in ESP 132 assembly is primarily liquid-phase fluid).

[0024] Under normal operating conditions (e.g., reservoir fluid 142 is flowing out of boreholes 140, ESP assembly 132 is powered by electrical energy, electric motor 122 is rotating and a gas slurry is not present in ESP assembly 132), reservoir fluid 142 enters inlets 136, reservoir fluid 142 is separated by gas separator assembly 138 into a gas phase fluid (or a mixed phase fluid having a higher liquid-to-gas ratio than reservoir fluid 142 entering inlet ports 136) and a liquid phase fluid (or a mixed phase fluid having a lower liquid-to-gas ratio than reservoir fluid 142 entering inlet ports 136). The gas phase fluid is discharged through the gas phase discharge ports 138 and the liquid phase fluid is discharged downstream to the centrifugal pump assembly 128 as liquid phase fluid 154.Under normal operating conditions, the gaseous phase fluid discharged into the annular space between casing 104 and the exterior of the ESP assembly 132 may comprise both the gaseous phase fluid 150 rising uphole in wellbore 102 and the liquid phase fluid 152 falling downhole in wellbore 102. The centrifugal pump assembly 128 flows the liquid phase fluid 154 (e.g., a portion of reservoir fluid 142) up the production piping 134 to a wellhead 156 at the surface 158.

[0025] An orientation of wellbore 102 and ESP assembly 132 is illustrated in FIG. 1 by an x-axis 160, a y-axis 162, and a z-axis 164. In one embodiment, the centrifugal pump assembly 128 comprises one or more centrifugal pump stages, wherein each stage comprises an impeller that is mechanically coupled to a shaft of Petition 870260045189, dated 05 / 13 / 2026, page 15 / 72 8 / 38 drive within the centrifugal pump assembly 128 and a corresponding diffuser which is stationary and retained by a housing of the centrifugal pump assembly 128. In one embodiment, the impellers may comprise a keyway that mates with a corresponding keyway on the drive shaft of the centrifugal pump assembly 128 and a key may be installed in the two keyways, wherein the impeller may be mechanically coupled to the drive shaft of the centrifugal pump assembly.

[0026] Returning now to FIG. 2, further details of the gas separator assembly 126 are described. The gas separator assembly 126 comprises a base 403, a housing 312, a crossover 350 and a head 355. The base 410 has inlet holes 136 and is threaded at a downstream end to an upstream end of the housing 312, for example, via the threaded coupling 403. In some contexts, the base 410 may be said to be mechanically coupled to the housing 312. In one embodiment, the base 410 couples to the sealing unit 124, for example, with a bolted connection (not shown) or a threaded coupling. The housing 312 may be a hollow cylindrical metal tube. In one embodiment, the interior of housing 312 may be machined or drilled in one or more locations to create slots or shallow holes for securing and retaining components within housing 312, for example, diffusers or other components.

[0027] In one embodiment, the housing 312 encloses a plurality of centrifugal pump stages 405, for example, a first centrifugal pump stage 405A and a second centrifugal pump stage 405B. Each centrifugal pump stage 405 comprises an impeller 406 mechanically coupled to a drive shaft 172 of the gas separator assembly 126 and a diffuser 408 that is retained and held stationary by the housing 312. In one embodiment, the impeller 406 may have a keyway that mates with a keyway in the drive shaft 172, and the keyway of the impeller 406 may be attached to the keyway in the drive shaft 172 by a key. In one embodiment, the impeller 406 may be mechanically coupled to the drive shaft 172 in a different manner. When the drive shaft 172 rotates, the impeller 406 rotates.The first stage of centrifugal pump 405A comprises a first impeller 406A and a first diffuser 408A; the second stage of centrifugal pump 405B. Petition 870260045189, dated 05 / 13 / 2026, page 16 / 72 9 / 38 comprises a second impeller 406B and a second diffuser 408B. Although two centrifugal pump stages 405A and 405B are illustrated in FIG. 2, in another embodiment there may be a single centrifugal pump stage 405, three centrifugal pump stages 405, four centrifugal pump stages 405, five centrifugal pump stages 405, six centrifugal pump stages 405 or more centrifugal pump stages 405 located between the base 410 and the fluid reservoir 172. The centrifugal pump stages 405 may be referred to as a first fluid mover in some contexts.In one embodiment, the centrifugal pump stages 405 of the gas separator assembly 126 are replaced by another fluid movement mechanism, for example, replaced by a screw conveyor mechanically coupled to the drive shaft 172, one or more impellers mechanically coupled to the drive shaft 172 (for example, without a corresponding diffuser) and / or a paddle wheel mechanically coupled to the drive shaft 172.

[0028] In one embodiment, the drive shaft 172 is mechanically coupled to a drive shaft of the sealing unit 124, and the drive shaft of the sealing unit 124 is mechanically coupled to a drive shaft of the electric motor 122. Thus, the drive shaft 172 and the impellers 406 (for example, impellers 406A and 406B in FIG. 2) of one or more centrifugal pump stages 405 are indirectly rotated by the electric motor 122 when it is energized by electrical power through the electric cable 135. The drive shaft 172 is mechanically coupled to a drive shaft of the centrifugal pump assembly 128 and transfers rotational energy to the drive shaft of the centrifugal pump assembly 136 and to the impellers of the centrifugal pump stages of the centrifugal pump assembly 136.Various different drive shaft mechanical couplings can be provided by splines cut into the shaft coupling ends and coupled by a splined coupler or hub. In another embodiment, drive shaft mechanical couplings can be provided by other devices.

[0029] Housing 312 also encloses a fluid reservoir 170. In one embodiment, the fluid reservoir 170 is formed as an annular space between the exterior of the drive shaft 172 and the inner wall of housing 312. In a Petition 870260045189, dated 05 / 13 / 2026, page 17 / 72 In the 10 / 38 embodiment, the fluid reservoir 170 is formed by a sleeve retained within the housing 312 which has an inlet at an upstream end of the fluid reservoir 170 that is fluidically coupled to an outlet of the second diffuser 408A and has an outlet 304 at a downstream end of the fluid reservoir 170 that is fluidically coupled to an upstream end of a second fluid mover, for example, a stationary auger 302.The fluid reservoir 170 can primarily retain liquid phase fluid when the ESP assembly 132 is experiencing normal operating conditions (e.g., when the electric motor 122 is energized and rotating, when reservoir fluid 142 is entering the wellbore 102 and flowing out of the inlet ports 136, and in the absence of a gas slurry), and this liquid phase fluid can be progressively mixed with gas when the ESP assembly 132 receives a gas slurry to extend the time that the gas separator assembly 126 is able to continue supplying at least some liquid phase fluid to the centrifugal pump assembly 128.

[0030] For example, at a first point in time, before the gas slurry reaches the inlet ports 136, the outlet 304 of the fluid reservoir 170 can supply fluid having a first gas-liquid ratio (GLR) to the stationary auger 302. As the gas from the gas slurry enters the inlet ports 136, at a second point in time (after the first point in time) the gas mixes with the fluid in the fluid reservoir 170, and the outlet 304 of the fluid reservoir 170 can supply fluid having a second GLR to the stationary auger 302, where the second GLR is greater than the first GLR. At a third point in time (after the second point in time), the gas continues to mix with the fluid in fluid reservoir 170, and outlet 304 of fluid reservoir 170 can supply fluid having a third GLR to the stationary auger 302, where the third GLR is greater than the second GLR.At a fourth point in time (after the third point in time), when the gas slurry passes through the ESP assembly 132 and is no longer extracted to the inlet ports 136, the reservoir fluid 142 entering the inlet ports 136 may again be primarily liquid phase fluid, and the outlet 304 of the fluid reservoir 170 may supply fluid having a fourth GLR to the stationary auger 302, where the fourth GLR is less than a. Petition 870260045189, dated 05 / 13 / 2026, p. 18 / 72 11 / 38 third GLR. At a fifth point in time (after the fourth point in time), outlet 304 of fluid reservoir 170 can supply fluid having a fifth GLR to the stationary auger 302, where the fifth GLR is less than the fourth GLR and approximately equal to the first GLR.It is noted that without the primarily liquid phase fluid retained in the fluid reservoir 170 at the time the gas slurry reached the ESP assembly 132 and the inlet ports 136, the GLR would have increased very rapidly and would have flowed unmixed gas from the outlets of the second diffuser 408B to the auger 302, from the stationary auger 302 to the separation chamber 303, from the separation chamber 303 to the liquid phase discharge 316 of the crossing 350 and from the liquid phase discharge 316 to the inlet of the centrifugal pump assembly 128, with the undesirable effect that the bearings of the centrifugal pump assembly 128 would lose lubrication, heat up rapidly, degrade rapidly and likely leave the centrifugal pump stages in the centrifugal pump assembly 128 in a gas blockage situation.In one embodiment, the gas separator assembly 126 may also have one or more centrifugal pump stages between the fluid reservoir 170 and the stationary auger 302.

[0031] The housing 312 also encloses a stationary auger 302. In one or more embodiments, the stationary auger 302 is disposed or positioned within a sleeve 322. The centrifugal pump stages 405 communicate or force the reservoir fluid 142 received at one or more inlet ports 136 through the fluid reservoir 170 and through the stationary auger 302. In one embodiment, an outer edge of the stationary auger 302 engages tightly with an inner surface 330 of the sleeve 322, and the flow of reservoir fluid 142 through the sleeve 322 is consequently confined to the passage or passages defined by the stationary auger 302. The sleeve 322 may be disposed or positioned within and retained by the housing 312. In one embodiment, the stationary auger 302 and the sleeve 322 may be constructed or manufactured as a single component.

[0032] In one embodiment, there is no sleeve 322 and the stationary auger 302 is disposed inside the housing 312. The stationary auger 202 can be retained inside the housing 312. In one embodiment, the stationary auger 302 engages with Petition 870260045189, dated 05 / 13 / 2026, p. 19 / 72 12 / 38 sealed form with an inner surface of the housing 312. In one embodiment, there is a space between the outer edges of the stationary auger 302 and the inner surface 330 of the sleeve 332 or a space between the outer edges of the stationary auger 302 and the inner surface of the housing 312.

[0033] In one or more embodiments, the stationary auger 302 comprises one or more propellers or vanes 324. In one or more embodiments, the propellers or vanes 324 may be crescent-shaped. In one or more embodiments, the stationary auger 302 comprises one or more propellers or vanes 324 arranged around a solid core, for example, a shaft 318 enclosing the drive shaft 172, or an open core (for example, a coreless auger or a helical auger). The stationary auger 302 may cause the reservoir fluid 142 to be separated into a liquid phase 308 and a gaseous phase 306 based, at least in part, on the rotational flow of the reservoir fluid 142.

[0034] For example, one or more propellers or vanes 324 can impart rotation to the reservoir fluid 142 as the reservoir fluid 142 flows through, via, or around one or more propellers or vanes 324. The stationary auger 302 can then be referred to as a fluid mover at least by virtue of imparting a rotary motion to the reservoir fluid 142 as the reservoir fluid 142 flows through the stationary auger 302. For example, the fluid mover 310 forces the reservoir fluid 142 at a velocity or flow rate into the sleeve 322 and up or through one or more propellers or vanes 324 of the stationary auger 302. The rotation of the reservoir fluid 142 induced by the stationary auger 302 can be based, at least in part, on the velocity or flow rate of the reservoir fluid 142 generated by the stages. 405 centrifugal pump.For example, centrifugal pump stages 405 can increase the flow rate or velocity of reservoir fluid 142 to increase the rotation of reservoir fluid 142 through the stationary auger 302 to create a more efficient and effective separation of reservoir fluid 142 into a plurality of phases, for example, a liquid phase fluid 428 and a gas phase fluid 426. As reservoir fluid 142 flows through the stationary auger 302, centrifugal, static friction, or both cause the heavier component of the... Petition 870260045189, dated 05 / 13 / 2026, p. 20 / 72 13 / 38 Reservoir fluid 142, a liquid-phase fluid 428, circulates along an outer perimeter of the stationary auger 112 while the lighter fluid component of reservoir fluid 142, the gas-phase fluid 426, is circulated along an inner perimeter of the stationary auger 302. In one or more embodiments, reservoir fluid 142 may begin to separate as it flows through the stationary auger 302. In one or more embodiments, liquid-phase fluid 428 may comprise residual gas that has not separated into the gas-phase fluid 426. However, the embodiments discussed in this document reduce this residual gas to protect the centrifugal pump assembly 128 against gas buildup or gas blockage.

[0035] In one embodiment, the stationary auger 302 is not present and, instead, a different type of second fluid mover is provided. The second fluid mover may be provided by an auger mechanically coupled to the drive shaft 172, a paddle wheel mechanically coupled to the drive shaft 172, a centrifugal rotor mechanically coupled to the drive shaft 172, or an impeller mechanically coupled to the drive shaft 172 that induces rotational motion of the reservoir fluid 142. In one embodiment, a third fluid mover is provided downstream of the stationary auger 302, for example, a paddle wheel may be installed downstream of the stationary auger 172 that induces and / or increases the rotational motion of the reservoir fluid 142.

[0036] A separation chamber 303 is provided downstream of the second fluid mover (e.g., the stationary auger 302) and downstream of the optional third fluid mover. An upstream end of the separation chamber 303 is fluidically coupled to a downstream end or outlet of the stationary auger 302 or another second fluid mover. Alternatively, the upstream end of the separation chamber 303 is fluidically coupled to a downstream end or outlet of the optional third fluid mover and is fluidically coupled to the third fluid mover and, through the third fluid mover, fluidically coupled to the second fluid mover. The separation chamber 303 is defined by an annular space formed between the inside of the housing 312 and the outside of the drive shaft 172. In one embodiment, the separation chamber is less than 36 Petition 870260045189, dated 05 / 13 / 2026, page 21 / 72 14 / 38 inches in length and at least 4 inches in length, at least 6 inches in length, at least 8 inches in length, at least 10 inches in length, at least 12 inches in length, or at least 14 inches in length. In one embodiment, the separation chamber is at least 6 inches long and less than 17 inches long. The stationary auger 302 (or other second fluid mover and / or third fluid mover) induces a rotational motion in the reservoir fluid 142. As the reservoir fluid 142 exits the stationary auger 302 (or other second fluid mover and / or third fluid mover) and enters the separation chamber 303, this rotational motion of the reservoir fluid 142 continues.The rotational movement of the reservoir fluid 142 within the separation chamber 303 induces the gas phase fluid (which is less dense than the liquid phase fluid) to concentrate near the drive shaft 172 and the liquid phase fluid to concentrate near the inner surface of the housing 312.

[0037] In one or more embodiments, the separated fluids (e.g., liquid phase fluid 428 and gas phase fluid 426) are directed to a crossover 350. For example, the crossover 350 may be disposed of or positioned at a downstream end of the separation chamber 303 or housing 312. In some contexts, the crossover 350 may be referred to as a gas flow path and liquid flow path separator. The crossover 350 may comprise a plurality of channels or define a plurality of channels, for example, a gas phase discharge 314 (a first path) and a liquid phase discharge 316 (a second path). A gaseous phase fluid 426 from reservoir fluid 142 can be discharged through gaseous phase discharge 314, out of gaseous phase discharge ports 138, and a liquid phase fluid 428 from reservoir fluid 142 can be discharged through liquid phase discharge 316.In one or more embodiments, the gas phase discharge 314 may correspond to any one or more discharge ports 138 of FIG. 1. In one or more embodiments, any one or more of the gas phase discharge orifices 314 and one or more liquid phase discharge ports 316 may be defined by a channel or path having an opening, for example, a teardrop-shaped opening, a. Petition 870260045189, dated 05 / 13 / 2026, p. 22 / 72 15 / 38 round opening, an elliptical opening, a triangular opening, a square opening, or another opening shape. The 350 crossing can be threaded at an upstream end by threaded coupling 351 to a downstream end of the housing 312. The 350 crossing can be threaded at a downstream end by threaded coupling 357 to a head 355. Alternatively, the head 355 can be integrated with the head 355 instead of being threaded to the head 355. The head 355 can provide screw holes for coupling to an upstream end of the centrifugal pump assembly 128. In some contexts, the 350 crossing can be said to be mechanically coupled at an upstream end to a downstream end of the housing 312.When the 350 crossing and the 355 head are not integrated as a single component, it can be said that the 350 crossing is mechanically coupled to a downstream end of an upstream end of the 355 head.

[0038] Returning now to FIG. 3, another embodiment of the gas separator assembly 126 is described. In one embodiment, the gas separator assembly 126 of FIG. 3 may be similar to the gas separator assembly 126 of FIG. 2, but, in addition, it may comprise a plurality of fluid reservoirs. In one embodiment, the gas separator assembly 126 may comprise a plurality of fluid reservoirs separated by a plurality of centrifugal pump stages 405, 415, 425.

[0039] For example, a second set of centrifugal pump stages 415 may be located within housing 312 downstream of fluid reservoir 170 and upstream of a second fluid reservoir 174. The second set of centrifugal pump stages 415 comprises a third pump stage 415A comprising a third impeller 416A mechanically coupled to the drive shaft 172, and a third diffuser 418A held stationary and retained by housing 312, and a fourth pump stage 415B comprising a fourth impeller 416B mechanically coupled to the drive shaft 172 and a fourth diffuser 418B held stationary and retained by housing 312. One or more inlets of the third impeller 416A are fluidically coupled to the fluid reservoir 170. In another embodiment, the second set of centrifugal pump stages 415 may comprise a single centrifugal pump stage, three-stage centrifugal pump, four-stage centrifugal pump, Petition 870260045189, dated 05 / 13 / 2026, page 23 / 72 16 / 38 five-stage centrifugal pump, six-stage centrifugal pump, or some other number of centrifugal pump stages. When the drive shaft 172 rotates, the third impeller 416A and the fourth impeller 416B rotate.

[0040] In one embodiment, the second fluid reservoir 174 is formed as an annular space between the exterior of the drive shaft 172 and the inner wall of the housing 312. Alternatively, the second fluid reservoir 174 is formed as an annular space between the exterior of the drive shaft 172 and the interior of a sleeve retained within the housing 312 which has an inlet at an upstream end of the second fluid reservoir 174 fluidically coupled to the outlets of the fourth diffuser 418B of the fourth centrifugal pump stage 415B and an outlet at a downstream end of the second fluid reservoir 174 which is fluidically coupled to another set of centrifugal pump stages, for example, centrifugal pump stages 425.

[0041] A third fluid reservoir 176 may be located downstream of the second fluid reservoir 174 and upstream of a third set of centrifugal pump stages. 425.In one embodiment, the third fluid reservoir 176 is formed as an annular space between the exterior of the drive shaft 172 and the inner wall of the housing 312. Alternatively, the third fluid reservoir 176 is formed as an annular space between the exterior of the drive shaft 172 and the interior of a sleeve retained within the housing 312 which has an inlet at an upstream end of the third fluid reservoir 176 and an outlet at a downstream end of the third fluid reservoir 176. Additional centrifugal pump stages (not shown) may be located between the second fluid reservoir 174 and the third fluid reservoir 176, for example, between the cut lines in FIG. 3. Additional fluid reservoirs (not shown) may be located between the second fluid reservoir 174 and the third fluid reservoir 176, for example, between the cut lines in FIG. 3.In one embodiment, one or more of the centrifugal pumps 405, 415, 425 may be supplied by a different type of fluid mover, for example, a screw conveyor mechanically coupled to the drive shaft 172, a paddle wheel mechanically coupled to the drive shaft 172, or an impeller mechanically coupled to the drive shaft 172. In one embodiment, an outlet of the... Petition 870260045189, dated 05 / 13 / 2026, page 24 / 72 17 / 38 second fluid reservoir 174 is fluidically coupled to an inlet of the third fluid reservoir 176. In one embodiment, the second fluid reservoir 174 may be fluidically coupled to the inlet of the third fluid reservoir 176 through internal passages of one or more centrifugal pump stages located between the second and third fluid reservoirs 174, 176.

[0042] In one embodiment, the second fluid reservoir 174 and the third fluid reservoir 176 may not be separated by any centrifugal pump stages, but may feature a spider bearing fixed and retained by the inside of the housing 312 to support the drive shaft 170. A large fluid reservoir may be formed by chaining together a plurality of fluid reservoirs together with spider bearings in between to support the drive shaft 170 at regular intervals, for example, every 6 inches, every 8 inches, every 9 inches, every 10 inches, every 11 inches, every 12 inches, every 13 inches, every 14 inches or every 16 inches. The spacing between the spider bearings may be dependent on a diameter of the drive shaft 170.For example, if the 170 drive shaft has a smaller diameter, the spider bearings can be placed closer together; if the 170 drive shaft has a larger diameter, the crosshead bearings can be placed further apart.

[0043] The second fluid reservoir 174 provides the same function as the fluid reservoir 172 and further extends the amount of time that the ESP assembly 132 can sustain a gas slurry (e.g., a larger gas slurry, a more extensive gas slurry) without losing liquid phase fluid flow 154 to the centrifugal pump assembly 128, without bearings in the centrifugal pump assembly 128 overheating, and without the centrifugal pump assembly 128 experiencing gas lock-up. The third fluid reservoir 176 (and possibly additional fluid reservoirs between the second fluid reservoir 174 and the third fluid reservoir 176) again provides greater capacity to sustain a gas slurry for a longer period of time without losing liquid phase fluid flow 154 to the centrifugal pump assembly 128.The greater the sum of the volume of fluid reservoir 170, the volume of the second fluid reservoir 174, and the volume of the third fluid reservoir (and the... Petition 870260045189, dated 05 / 13 / 2026, p. 25 / 72 18 / 38 volumes of any other intervening fluid reservoirs), the longer the duration of the gas slurry (the greater the gas slurry) that the ESP 132 assembly can sustain.

[0044] In one embodiment, the gas separator assembly 126 has one or more centrifugal pump stages downstream of the third fluid reservoir 176 and upstream of a paddle wheel 327 (in FIG. 3, the stationary auger 302 is replaced by a paddle wheel 327 that imparts rotational motion to the reservoir fluid 142 before it flows into the separation chamber 303), for example, a fifth centrifugal pump stage 425A and a sixth centrifugal pump stage 425B. The fifth stage of centrifugal pump 425A comprises a fifth impeller 426A mechanically coupled to the drive shaft 172 and a fifth diffuser retained and held stationary by the housing 312. The sixth stage of centrifugal pump 425B comprises a sixth impeller 426B mechanically coupled to the drive shaft 172 and a sixth diffuser retrained and held stationary by the housing 312. When the drive shaft 172 rotates, the fifth impeller 426A and the sixth impeller 426B are rotated.Although two centrifugal pump stages 425A, 425B are illustrated downstream of the third fluid reservoir 176 and upstream of the paddle wheel 303, in another embodiment a single centrifugal pump stage, three centrifugal pump stages, four centrifugal pump stages, five centrifugal pump stages, six centrifugal pump stages or more centrifugal pump stages may be located downstream of the third fluid reservoir 176 and upstream of the stationary auger 302 in the gas separator assembly 126. The paddle wheel 303 is mechanically coupled to the drive shaft 172.

[0045] Returning now to FIG. 4, the fluid reservoir 170 is illustrated as an annular space defined between the drive shaft 172 and the inner surface 171 (e.g., the inner wall of the housing 312 or a sleeve within the inner wall of the housing 312). The volume of the annular space defined by the fluid reservoir is best shown in FIG. 5A and FIG. 5B. The volume can be found as the cross-sectional area of ​​the annular space 180 (best seen in FIG. 5B) multiplied by the length of the fluid reservoir 170 indicated as 'L1' in FIG. 4 and FIG. 5A. The cross-sectional area of ​​the annular space 180 can be found as the difference in the area of ​​a circle of diameter D2 (the inner diameter of the housing 312 or Petition 870260045189, dated 05 / 13 / 2026, page 26 / 72 19 / 38 (the inner diameter of the sleeve) and the area of ​​a circle of diameter D1 (the diameter of the drive shaft 172). By increasing the sum volume of fluid reservoirs within the gas separator assembly 126, the gas separator assembly 126 is able to sustain gas slugs of increasing duration.

[0046] In one embodiment, the fluid reservoir 170 is at least 2 inches long and less than 14 inches long. In one embodiment, the fluid reservoir 170 is at least 6 inches long and less than 14 inches long. In one embodiment, the fluid reservoir 170 is at least 14 inches long and less than 28 inches long. In one embodiment, the fluid reservoir 170 is at least 17 inches long and less than 34 inches long. In one embodiment, the fluid reservoir 170 is at least 24 inches long and less than 42 inches long. In one embodiment, the annular space 180 of the fluid reservoir 170 is at least 18 cubic inches and less than 1,000 cubic inches. In one embodiment, the annular space 180 of the fluid reservoir 170 has at least 50 cubic inches and less than 1,000 cubic inches.In one embodiment, the fluid reservoir 170 may comprise one or more crosshead bearings to support the drive shaft 172 as discussed further below.

[0047] In one embodiment, the gas separator assembly 126 may be less than 500 feet long and at least 5 feet long, at least 8 feet long, at least 10 feet long, at least 12 feet long, at least 14 feet long, at least 16 feet long, at least 18 feet long, at least 20 feet long, at least 22 feet long, at least 24 feet long, at least 26 feet long, at least 28 feet long, at least 30 feet long, at least 32 feet long, at least 34 feet long, at least 40 feet long, at least 50 feet long, at least 60 feet long, at least 70 feet long, at least 80 feet long, at least 90 feet long, at least 100 feet long, at least 120 feet long, or at least 140 feet long. length. With gas separator assemblies Petition 870260045189, dated 05 / 13 / 2026, page 27 / 72 20 / 38 long 126, the gas separator assembly may comprise a first housing that is thread-coupled with a second housing, and the first housing and the second housing joined together contain the centrifugal pump stages, the fluid reservoirs, and the stationary auger 302 of the gas separator assembly 126. With long gas separator assemblies 126, the drive shaft 172 may comprise two drive shafts that are coupled together by a splined coupling.

[0048] In one embodiment, during normal operation (e.g., no gas slurry present in the inlet ports 136), liquid-phase fluid can fill the annular space 210 from the bottom end of the gas separator assembly 126 (e.g., at the fluid inlets 136) to the level of the discharge ports 138. This liquid-phase fluid can also mix with gas in the inlet ports 136 and centrifugal pump stages 405 when a gas slurry reaches the ESP assembly 132. Thus, the longer the gas separator assembly 126, the greater the volume of liquid-phase fluid retained in the annular space 210 and the longer the ESP assembly 132 can sustain a gas slurry while still feeding some of the liquid-phase fluid to the centrifugal pump assembly 128. Thus, extending the length of the gas separator assembly 126 with fluid reservoirs 170, 174, 176 can also create additional liquid fluid reservoirs in the annular space 210.

[0049] Returning now to FIG. 6A, a volume of the annular space 182 is illustrated. A spider bearing 184 is illustrated at about half the length L2 of the annular space volume 182. By supporting the drive shaft 172 in an intermediate portion, the length L2 can be larger, for example, it can be increased to 16 inches, 18 inches, 20 inches, 22 inches, 24 inches, 26 inches or 28 inches. The use of spider bearings 184 can easily increase the sum of fluid reservoir volumes within the gas separator and pump assembly 126. In FIG. 6B, a different view of the spider bearing 184 is illustrated. The spider bearing 184 may comprise three struts 188 that stabilize a central bearing 186 of the spider bearing 184. The struts 188 may be fixed by the housing 312.The struts 188 can assume a vane shape oriented to minimally block the communication of reservoir fluid 142 through the spider bearing 184, between the struts 188. The bearing. Petition 870260045189, dated 05 / 13 / 2026, p. 28 / 72 21 / 38 spider 184 provides fluid communication paths between the struts 188. Although FIG. 6A and FIG. 6B illustrate a spider bearing 184 with three struts 188, spider bearings 184 can comprise two struts, four struts, five struts, or some larger number of struts 188. In FIG. 6C, the number of crosshead bearings 184 can be increased to any number, thus increasing the volume of the annular space defined by the fluid reservoir 170, 174, 176. As shown in FIG. 6C, three crosshead bearings 184a, 184b, 184c are used and can provide a fluid reservoir length L3 of 170, 174, 176 of 24 inches, 32 inches, 40 inches, 44 inches, 48 ​​inches, 52 inches or 56 inches.

[0050] In one embodiment, the drive shaft 172 has an outside diameter of about 7 / 8 inch (e.g., about 0.875 inch) and the gas separator assembly 126 has an outside diameter of about 4 inches. In this case, the inside diameter of the housing 312 or the sleeve within the inner wall of the housing 312 is about 3 ½ inches (e.g., 3.5 inches). These dimensions give a value of D1 of about 0.875 inches, a value of D2 of about 3.5 inches. The cross-sectional area in FIG. 5B for these values ​​of D1 and D2 can be calculated to be about 9.0198 square inches. A corresponding annular space volume can be calculated for a plurality of different values ​​for L1 as follows: Value of L1 Corresponding annular space volume 2” 18.040 cubic inches 4” 36.079 cubic inches 6” 54.119 cubic inches 8” 72.158 cubic inches 10” 90.198 cubic inches 12” 108.24 cubic inches 14” 126.28 cubic inches

[0051] In one embodiment, the drive shaft 172 has an outside diameter of about 1 1 / 16 inches (e.g., about 0.6875 inches) and the gas separator assembly 126 has an outside diameter of about 4 inches. In this case, the inside diameter of the housing 312 or the sleeve within the inner wall of the housing 312 is about 3 1 / 2 inches (e.g., 3.5 inches). The cross-sectional area in FIG. 5B for these values ​​of D1 and D2 can be calculated to be about 9.2499 square inches. A corresponding annular space volume can be calculated for a Petition 870260045189, dated 05 / 13 / 2026, page 29 / 72 22 / 38 plurality of different values ​​for L1 as follows: Value of L1 Corresponding annular space volume 2” 18,500 cubic inches 4” 37,000 cubic inches 6” 55,499 cubic inches 8” 73,999 cubic inches 10” 92,499 cubic inches 12” 111,000 cubic inches 14” 129,500 cubic inches

[0052] In one embodiment, the drive shaft 172 has an outside diameter of about 1 3 / 16 inches (e.g., about 1.1875 inches) and the gas separator assembly 126 has an outside diameter of about 5.38 inches. In this case, the inside diameter of the housing 312 or the sleeve within the inner wall of the housing 312 is about 4.77 inches. The cross-sectional area in FIG. 5B for these values ​​of D1 and D2 can be calculated to be about 16.763 square inches. A corresponding annular space volume can be calculated for a plurality of different values ​​for L1 as follows: Value of L1 Corresponding annular space volume 2” 33.526 cubic inches 4” 67.052 cubic inches 6” 100.58 cubic inches 8” 134.10 cubic inches 10” 167.63 cubic inches 12” 201.16 cubic inches 14” 234.68 cubic inches

[0053] In one embodiment, the drive shaft 172 has an outer diameter of about 1 inch, and the gas separator assembly 126 has an outer diameter of about 5.38 inches. In this case, the inner diameter of the housing 312 or the sleeve within the inner wall of the housing 312 is about 4.77 inches. The cross-sectional area in FIG. 5B for these values ​​of D1 and D2 can be calculated to be about 17.085 square inches. A corresponding annular space volume can be calculated for a plurality of different values ​​for L1 as follows: Petition 870260045189, dated 05 / 13 / 2026, page 30 / 72 23 / 38 Value of L1 Corresponding annular space volume 2” 34.170 cubic inches 4” 68.340 cubic inches 6” 102.51 cubic inches 8” 136.68 cubic inches 10” 170.85 cubic inches 12” 205.02 cubic inches 14” 239.19 cubic inches

[0054] The diameter of the drive shaft 172 and the inner diameter of the housing 312 or sleeve can be determined by the wellbore environment to which the ESP 132 assembly may be deployed. By varying the length L1, however, more or less annular space volume can be created in the fluid reservoir 170. More annular space volume provides more buffer or reserve against gas slugs. At the same time, the length L1 cannot be increased indefinitely by virtue of the drive shaft 172 being unsupported and unstabilized in the fluid reservoir 170. In one embodiment, this length L1 may desirably be restricted to less than 16 inches, less than 15 inches, less than 14 inches, less than 13 inches, less than 12 inches, less than 11 inches, or less than 10 inches. The maximum prudent length of L1 depends on the drive shaft diameter 172 and the value of D1.A drive shaft with a larger diameter 172 may allow for a relatively greater maximum length of L1, while a drive shaft with a smaller diameter 172 may allow for a relatively smaller maximum length of L1. Greater annular space volume – and consequently greater capacity to sustain long-duration gas slugs – can be provided by increasing the length L1 or by increasing the number of fluid reservoirs within the gas separator assembly 126. Greater annular space volume can be provided by increasing the length L1 by adding crosshead bearings 184 and desirable intervals within a single fluid reservoir to maintain the desired stability and support for the drive shaft 172.

[0055] Note that the substantial open volumes between centrifugal pump stages and a stationary auger prescribed in this document are not conventionally included in gas separator assemblies by virtue of the additional materials required to do so (longer housing 312, for example), and greater extensions. Petition 870260045189, dated 05 / 13 / 2026, page 31 / 72 24 / 38 where the drive shaft 172 is not supported occurs.

[0056] Returning now to FIG. 7A and FIG. 7B, a method 900 is described. In one embodiment, the method 900 is a method of lifting liquid into a wellbore. In block 902, the method 900 comprises passing an electric submersible pump (ESP) assembly into a wellbore, wherein the ESP assembly comprises an electric motor, a gas separator assembly having a fluid inlet and one or more liquid phase discharge ports (for example, (A) a single assembly of one or more liquid phase discharge ports associated with a single crossing or (B) two assemblies of one or more liquid phase discharge ports, wherein each assembly of liquid phase discharge ports is associated with a different crossing as, for example, in a tandem gas separator configuration) and a centrifugal pump assembly having a fluid inlet fluidically coupled to the liquid discharge port of the gas separator assembly.In one embodiment, method 900 can be practiced with a tandem gas separator assembly in place of the single gas separator assembly described in this document with reference to block 902. A tandem gas separator assembly is illustrated in FIG. 9 and described further below.

[0057] In block 904, method 900 comprises rotating a drive shaft of the gas separator assembly by an electric motor of the ESP assembly. In block 906, method 900 comprises extracting reservoir fluid from the wellbore to the gas separator assembly by a first fluid mover of the gas separator assembly that is coupled to the drive shaft. In block 908, method 900 comprises moving the downstream reservoir fluid by the first fluid mover (e.g., centrifugal pump stages 405A and 405B) within the gas separator assembly.

[0058] In block 910, method 900 comprises filling an annular space within the gas separator assembly with reservoir fluid, wherein the annular space is defined between an inner surface of the separator assembly and an outer surface of the drive shaft, and wherein the annular space is located downstream of the first fluid mover. In one embodiment, the annular space is provided by the fluid reservoir 170 and may be defined between the drive shaft 172 and an inner surface of the housing 312 or by an inner surface of a sleeve retained by the housing 312. In Petition 870260045189, dated 05 / 13 / 2026, page 32 / 72 In one embodiment, the annular space volume is at least 50 cubic inches and less than 1,000 cubic inches. In block 912, method 900 comprises draining fluid from the annular space reservoir within the gas separator assembly to a second fluid mover of the gas separator assembly, wherein the second fluid mover is located downstream of the annular space. In one embodiment, the second fluid mover may be the stationary auger 302. In one embodiment, the second fluid mover may be the paddle wheel 327. In one embodiment, the second fluid mover may be an impeller without a diffuser.

[0059] In block 914, method 900 comprises moving the fluid from the downstream reservoir by the second fluid mover to a separator of the gas flow path and the liquid flow path (e.g., the 350 crossing) of the gas separator assembly. In one embodiment, the processing of block 914 comprises inducing a rotational motion in the reservoir fluid by the second fluid mover and flowing the reservoir fluid to a separation chamber located downstream of the second fluid mover and upstream of the separator of the gas flow path and the liquid flow path. In one embodiment, the processing of block 914 comprises separating the gas phase fluid from the liquid phase fluid in the separation chamber by the rotational motion of the reservoir fluid.In block 916, method 900 comprises discharging a portion of the reservoir fluid through a gas phase discharge orifice of the separator from the gas flow path and liquid flow path to an exterior of the gas separator assembly.

[0060] In block 918, method 900 comprises discharging a portion of the fluid from the reservoir through a liquid phase discharge orifice of the gas flow path separator and the liquid flow path downstream of the gas separator assembly to the centrifugal pump assembly.

[0061] In block 920, method 900 comprises pumping the portion of the reservoir fluid discharged through the liquid phase discharge orifice by the centrifugal pump assembly. In block 922, method 900 comprises draining the portion of the reservoir fluid discharged through the liquid phase discharge orifice out of a discharge from the centrifugal pump assembly through a production pipeline to a Petition 870260045189, dated 05 / 13 / 2026, page 33 / 72 26 / 38 surface location.

[0062] In one embodiment, method 900 further comprises extracting gas from the wellbore to the gas separator by the first fluid mover; flowing the gas downstream by the first fluid mover within the gas separator assembly; mixing the gas with reservoir fluid retained by the annular space to form a gas-fluid mixture; and flowing the gas-fluid mixture from the annular space within the gas separator assembly to the second fluid mover of the gas separator assembly. In one embodiment, method 900 further comprises stabilizing the drive shaft by a spider bearing that is concentric with the drive shaft and located within the annular space within the gas separator assembly, wherein the spider bearing provides flow paths for the reservoir fluid between the spider bearing supports.In one embodiment, the 900 method comprises stabilizing the drive shaft by a plurality of spider bearings, wherein each spider bearing is concentric with the drive shaft, is located within the annular space within the gas separator assembly, and provides flow paths for reservoir fluid between spider bearing supports. The plurality of crosshead bearings may be separated from each other by at least 4 inches and less than 16 inches, at least 6 inches and less than 14 inches, or at least 8 inches and less than 12 inches.

[0063] Returning now to FIG. 8A and FIG. 8B, a method 950 is described. In one embodiment, method 950 is a method of mounting an electric submersible pump (ESP) assembly in a wellbore location. In block 952, method 950 comprises coupling a downstream end of an electric motor to an upstream end of a sealing unit. In block 954, method 950 comprises lowering the electric motor and the sealing unit partially into the wellbore.

[0064] In block 956, method 950 comprises coupling a downstream end of the sealing unit to an upstream end of a gas separator assembly, wherein the gas separator assembly comprises a drive shaft; a fluid reservoir arranged concentrically around the drive shaft and located downstream of the first fluid mover, wherein an inner surface of the reservoir of Petition 870260045189, dated 05 / 13 / 2026, page 34 / 72 27 / 38 fluid and an external surface of the drive shaft define a first annular space that is fluidically coupled to the fluid outlet of the first fluid mover; a second fluid mover having a fluid inlet and a fluid outlet, wherein the second fluid mover is located downstream of the fluid reservoir and wherein the fluid inlet of the second fluid mover is fluidically coupled to the first annular space; a separation chamber arranged concentrically around the drive shaft and located downstream of the second fluid mover,wherein an inner surface of the separation chamber and the outer surface of the drive shaft define a second annular space that is fluidically coupled to the fluid outlet of the second fluid mover; and a gas flow path and liquid flow path separator having a gas phase discharge orifice open to an exterior of the assembly and a liquid phase discharge orifice, wherein the gas flow path and liquid flow path separator has a fluid inlet that is fluidically coupled to the second annular space.

[0065] In Block 958, Method 950 comprises lowering the electric motor, sealing unit, and gas separator assembly partially into the wellbore. In one embodiment, the gas separator assembly comprises a spider bearing concentric with the drive shaft and located within the first fluid reservoir,In one embodiment, the gas separator assembly comprises a plurality of crosshead bearings concentric with the drive shaft and located within the first fluid reservoir, wherein the crosshead bearings each comprise thrusts that provide fluid communication paths between the thrusts. In another embodiment, the gas separator assembly comprises a plurality of fluid reservoirs. In another embodiment, the gas separator assembly comprises a second fluid reservoir arranged concentrically around the drive shaft and located downstream of the second fluid mover, wherein an inner surface of the second fluid reservoir and an outer surface of the drive shaft define a second annular space that is fluidically coupled to the fluid outlet of the second fluid mover.where the second fluid mover is attached, Petition 870260045189, dated 05 / 13 / 2026, page 35 / 72 28 / 38 mechanically to the drive shaft and comprises a third fluid mover having a fluid inlet and a fluid outlet, wherein the third fluid mover is located downstream of the second fluid reservoir and wherein the fluid inlet of the third fluid reservoir is fluidically coupled to the second fluid reservoir, wherein the separation chamber and the separator of the gas flow path and the liquid flow path are located downstream of the third fluid mover, wherein the upstream end of the separation chamber is fluidically coupled to the fluid outlet of the third fluid mover and wherein the fluid inlet of the separation chamber is fluidically coupled to the fluid outlet of the second fluid mover through the third fluid mover and through the second fluid reservoir.

[0066] In block 960, method 950 comprises coupling a downstream end of the gas separator assembly to an upstream end of the centrifugal pump assembly. In block 962, method 950 comprises partially lowering the electric motor, the sealing unit, the gas separator assembly, and the centrifugal pump assembly into the well.

[0067] Returning now to FIG. 9, a tandem gas separator configuration of gas separator assembly 126 is described. A tandem gas separator assembly comprises two gas separator assemblies where an upstream gas separator assembly discharges liquid-phase fluid out of its intersection directly to the inlet of the first fluid mover of the downstream separator assembly, for example, directly to an inlet of a single-stage centrifugal pump impeller. The upstream gas separator assembly has its own intersection and the downstream gas separator assembly has its own intersection. In one embodiment, a tandem gas separator assembly can be used to distribute a richer liquid (e.g., lower gas-fluid ratio) to the centrifugal pump assembly 128, separating gas twice from the reservoir fluid 142.In one embodiment, once some of the reservoir fluid 142 (e.g., a gas-phase rich fraction) is depleted, the fluid flow rate to the downstream gas separator is inherently lower than the fluid flow rate to the upstream gas separator. In one embodiment, the fluid movers of... Petition 870260045189, dated 05 / 13 / 2026, page 36 / 72 29 / 38 upstream gas separators can be designed for a higher fluid flow rate, and downstream gas separators can be designed for a lower fluid flow rate.

[0068] A large part of the tandem gas separator assembly 126 illustrated in FIG. 9 is composed of components described above with reference to FIG. 2 and FIG. 3. The tandem gas separator assembly 126 comprises a single base 410 having inlet ports 136. The upstream gas separator assembly comprises a centrifugal pump 405, a first fluid reservoir 170A, a stationary auger 302, a first separation chamber 303A, and a crossover 350. In one embodiment, the centrifugal pump 405 can be replaced in the upstream gas separator by an auger mechanically coupled to the drive shaft 172 or by a paddle wheel 327. In another embodiment, the stationary auger 302 can be replaced by a paddle wheel 327 mechanically coupled to the drive shaft 172 or an impeller mechanically coupled to the drive shaft 172.A first gas-phase fluid 426A is discharged by the gas-phase discharge 314 of the upstream gas separator into the annular space 210, and a first liquid-phase fluid 428A is discharged by the liquid-phase discharge 316 at the inlet of the centrifugal pump 425 of the downstream gas separator. Note that there is no base having inlet orifices between the intersection 350 of the upstream gas separator and the centrifugal pump 425 of the downstream gas separator.

[0069] The gas separator downstream of the tandem gas separator assembly 126 comprises a centrifugal pump 425, a second fluid reservoir 170B, a paddle wheel 327, a second separation chamber 303B, and a crossover 350. In one embodiment, the centrifugal pump 425 can be replaced in the downstream gas separator by a screw conveyor mechanically coupled to the drive shaft 172. In one embodiment, the paddle wheel 327 can be replaced by a stationary screw conveyor 302 or by an impeller mechanically coupled to the drive shaft 172. A second gas-phase fluid 426B is discharged by the gas-phase discharge 314 from the downstream gas separator to the annular space 210, and a second liquid-phase fluid 428B is discharged by the liquid-phase discharge 316 to the assembly of centrifugal pump 128. Additional disclosure Petition 870260045189, dated 05 / 13 / 2026, page 37 / 72 30 / 38

[0070] The following are specific, non-limiting options under this disclosure:

[0071] A first embodiment, which is a downhole gas separator assembly, comprising a drive shaft, a first fluid mover mechanically coupled to the drive shaft and having a fluid inlet and a fluid outlet, a fluid reservoir arranged concentrically around the drive shaft and located downstream of the first fluid mover, wherein an inner surface of the fluid reservoir and an outer surface of the drive shaft define a first annular space that is fluidically coupled to the fluid outlet of the first fluid mover, a second fluid mover having a fluid inlet and a fluid outlet, wherein the second fluid mover is located downstream of the fluid reservoir and wherein the fluid inlet of the second fluid mover is fluidically coupled to the first annular space,A separation chamber arranged concentrically around the drive shaft and located downstream of the second fluid mover, wherein an inner surface of the separation chamber and the outer surface of the drive shaft define a second annular space that is fluidically coupled to the fluid outlet of the second fluid mover, and a gas flow path separator and liquid flow path separator having a gas phase discharge orifice open to an exterior of the assembly and a liquid phase discharge orifice, wherein the gas flow path separator and liquid flow path separator has a fluid inlet that is fluidically coupled to the second annular space.

[0072] A second embodiment, which is the downhole gas separator assembly of the first embodiment, wherein the first annular space has a volume of at least 18 cubic inches and less than 1,000 cubic inches.

[0073] A third embodiment, which is the downhole gas separator assembly of either of the first and second embodiments, wherein a distance between the fluid inlet of the first fluid mover and the gas phase discharge orifice of the separator of the gas flow path and the liquid flow path is at least 4 feet and less than 500 feet. Petition 870260045189, dated 05 / 13 / 2026, p. 38 / 72 31 / 38

[0074] A fourth embodiment, which is the downhole gas separator assembly of any of the first through third embodiments, wherein the fluid reservoir is at least 6 inches long and less than 17 inches long.

[0075] A fifth embodiment, which is the downhole gas separator assembly of any of the first through fourth embodiments, further comprising a spider bearing located within the fluid reservoir having a central through hole that encircles the drive shaft.

[0076] A sixth embodiment, which is the fifth embodiment of the downhole gas separator assembly, wherein the fluid reservoir is at least 17 inches long and less than 34 inches long.

[0077] A seventh embodiment, which is the downhole gas separator assembly of any of the first through sixth embodiments, further comprising a housing, wherein the inner surface of the fluid reservoir and the inner surface of the separation chamber are provided by an inner surface of the housing, wherein the first fluid mover and the second fluid mover are located within the housing, and wherein the gas flow path separator and the liquid flow path separator are mechanically coupled to the housing.

[0078] An eighth embodiment, which is the downhole gas separator assembly of any of the first through seventh embodiments, further comprising a housing, wherein the inner surface of the separation chamber is provided by an inner surface of the housing, wherein the inner surface of the fluid reservoir is provided by a sleeve which is retained within the housing, wherein the first fluid mover and the second fluid mover are located within the housing, and wherein the separator of the gas flow path and the liquid flow path is mechanically coupled to the housing.

[0079] A ninth embodiment, which is the downhole gas separator assembly of any of the first through eighth embodiments, wherein the second fluid mover is a stationary auger, an auger mechanically coupled to the drive shaft, an impeller mechanically coupled to the drive shaft, a centrifugal rotor mechanically coupled to the drive shaft, or a paddle wheel coupled Petition 870260045189, dated 05 / 13 / 2026, page 39 / 72 32 / 38 mechanically to the drive shaft.

[0080] A tenth embodiment, which is the downhole gas separator assembly of any of the first through ninth embodiments, wherein the first fluid mover is a centrifugal pump having at least one centrifugal pump stage wherein each centrifugal pump stage comprises an impeller mechanically coupled to the drive shaft and a diffuser.

[0081] An eleventh embodiment, which is the downhole gas separator assembly of any of the first through tenth embodiments, wherein the second fluid mover is mechanically coupled to the drive shaft and further comprising a second fluid reservoir arranged concentrically around the drive shaft and located downstream of the second fluid mover, wherein an inner surface of the second fluid reservoir and an outer surface of the drive shaft define a third annular space that is fluidically coupled to the fluid outlet of the second fluid mover and a third fluid mover having a fluid inlet and a fluid outlet, wherein the third fluid mover is located downstream of the second fluid reservoir and is located upstream of the separation chamber,wherein the fluid inlet of the third fluid mover is fluidically coupled to the third annular space and the fluid outlet of the third fluid mover is fluidically coupled to the second annular space.

[0082] A twelfth embodiment, which is the downhole gas separator assembly of any of the first through eleventh embodiments, further comprising a base having an inlet, a fourth fluid mover mechanically coupled to the drive shaft, located upstream of the base, having a fluid outlet and having a fluid inlet fluidically coupled to the base inlet, a third fluid reservoir arranged concentrically around the drive shaft and located downstream of the fourth fluid mover, wherein an inner surface of the third fluid reservoir and the outer surface of the drive shaft define a fourth annular space that is fluidically coupled to the fluid outlet of the fourth fluid mover, a fifth fluid mover having a fluid inlet and a fluid outlet, wherein the fifth fluid mover is located downstream of the Petition 870260045189, dated 05 / 13 / 2026, page 40 / 72 33 / 38 third fluid reservoir, and wherein the fluid inlet of the fifth fluid mover is fluidically coupled to the fourth annular space, a second separation chamber arranged concentrically around the drive shaft and located downstream of the fifth fluid mover, wherein an inner surface of the second separation chamber and the outer surface of the drive shaft define a fifth annular space that is fluidically coupled to the fluid outlet of the fifth fluid mover and a second separator of the gas flow path and the liquid flow path having a gas phase discharge orifice open to an exterior of the assembly and a liquid phase discharge orifice fluidically coupled to the fluid inlet of the first fluid mover, and wherein the separator of the gas flow path and the liquid flow path has a fluid inlet fluidically coupled to the fifth annular space.

[0083] A thirteenth embodiment, which is a method of lifting liquid in a wellbore, comprising passing an electric submersible pump (ESP) assembly into a wellbore, wherein the ESP assembly comprises an electric motor, a gas separator assembly having a fluid inlet and a liquid phase discharge port and a centrifugal pump assembly having a fluid inlet fluidically coupled to the liquid discharge port of the gas separator assembly, rotating a drive shaft of the gas separator assembly by an electric motor of the ESP assembly, extracting reservoir fluid from the wellbore to the gas separator assembly by a first fluid mover of the gas separator assembly that is coupled to the drive shaft, moving the reservoir fluid downstream by the first fluid mover within the gas separator assembly, filling an annular space within the gas separator assembly with the reservoir fluid,wherein the annular space is defined between an inner surface of the gas separator assembly and an outer surface of the drive shaft and wherein the annular space is located downstream of the first fluid mover, flowing fluid from the reservoir of the annular space within the gas separator assembly to a second fluid mover of the gas separator, wherein the second fluid mover is located downstream of the annular space, moving fluid from the downstream reservoir by the second fluid mover to a, Petition 870260045189, dated 05 / 13 / 2026, page 41 / 72 34 / 38 gas flow path separator and liquid flow path separator of the gas separator assembly, discharge a portion of the reservoir fluid through a gas phase discharge port of the gas flow path and liquid flow path separator to an exterior of the gas separator assembly, discharge a portion of the reservoir fluid through a liquid phase discharge port of the gas flow path separator and the downstream liquid flow path of the gas separator assembly to the centrifugal pump assembly, pump the discharged reservoir fluid portion through the liquid phase discharge port by the centrifugal pump assembly, and drain the discharged reservoir fluid portion through the liquid phase discharge port out of a discharge from the centrifugal pump assembly through a production pipeline to a surface location.

[0084] A fourteenth embodiment, which is the method of the thirteenth embodiment, further comprising extracting gas from the well to the gas separator by the first fluid mover, flowing the gas downstream by the first fluid mover within the gas separator assembly, mixing the gas with the reservoir fluid retained by the annular space to form a gas and fluid mixture, and flowing the gas and fluid mixture from the annular space within the gas separator assembly to the second fluid mover of the gas separator assembly.

[0085] A fifteenth modality, which is the method of the fourteenth modality, in which a volume of the annular space is at least 50 cubic inches and less than 1,000 cubic inches.

[0086] A sixteenth embodiment, which is the twelfth embodiment method, further comprising stabilizing the drive shaft by a spider bearing which is concentric with the drive shaft and which is located within the annular space within the gas separator assembly, wherein the spider bearing provides flow paths for the reservoir fluid between the spider bearing struts.

[0087] A seventeenth embodiment, which is the method of the twelfth embodiment, further comprising the stabilization of the drive shaft by a spider bearing which is concentric with the drive shaft and which is located within the annular space within the gas separator assembly, wherein the spider bearing provides Petition 870260045189, dated 05 / 13 / 2026, page 42 / 72 35 / 38 flow paths for fluid from the reservoir between the spider bearing supports.

[0088] An eighteenth embodiment, which is the method of the seventeenth embodiment, in which each spider bearing is separated from the other spider bearing by at least 4 inches and less than 16 inches.

[0089] A nineteenth embodiment, which is a method of mounting an electric submersible pump (ESP) assembly in a wellbore location, comprising coupling a downstream end of an electric motor to an upstream end of a sealing unit, lowering the electric motor and the sealing unit partially into the wellbore, coupling a downstream end of the sealing unit to an upstream end of a gas separator assembly, wherein the gas separator assembly comprises a drive shaft, a first fluid mover mechanically coupled to the drive shaft and having a fluid inlet and a fluid outlet, a fluid reservoir arranged concentrically around the drive shaft and located downstream of the first fluid mover,wherein an inner surface of the fluid reservoir and an outer surface of the drive shaft define a first annular space that is fluidically coupled to the fluid outlet of the first fluid mover, a second fluid mover having a fluid inlet and a fluid outlet, wherein the second fluid mover is located downstream of the fluid reservoir and wherein the fluid inlet of the second fluid mover is fluidically coupled to the first annular space, a separation chamber arranged concentrically around the drive shaft and located downstream of the second fluid mover,wherein an inner surface of the separation chamber and the outer surface of the drive shaft define a second annular space that is fluidically coupled to the fluid outlet of the second fluid mover and a separator of the gas flow path and liquid flow path having a gas phase discharge orifice open to an exterior of the assembly and a liquid phase discharge orifice, wherein the separator of the gas flow path and liquid flow path has a fluid inlet that is fluidically coupled to the second annular space, lower the electric motor, the sealing unit and the gas separator assembly partially into the wellbore, couple one downstream end of the assembly, Petition 870260045189, dated 05 / 13 / 2026, page 43 / 72 36 / 38 gas separator at one end upstream of the centrifugal pump assembly, and lower the electric motor, sealing unit, gas separator assembly and centrifugal pump assembly partially into the wellbore.

[0090] A twentieth embodiment, which is the nineteenth embodiment method, in which the gas separator assembly comprises a plurality of fluid reservoirs.

[0091] A twenty-first embodiment, which is the method of either of the nineteenth and twentieth embodiments, wherein the second fluid mover is mechanically coupled to the drive shaft and the gas separator assembly comprises a second fluid reservoir arranged concentrically around the drive shaft and located downstream of the second fluid mover, wherein an inner surface of the second fluid reservoir and an outer surface of the drive shaft define a second annular space that is fluidically coupled to the fluid outlet of the second fluid mover, and a third fluid mover having a fluid inlet and a fluid outlet, wherein the third fluid mover is located downstream of the second fluid reservoir and wherein the fluid inlet of the third fluid reservoir is fluidically coupled to the second fluid reservoir,wherein the gas flow path separator and the liquid flow path separator are located downstream of the third fluid mover, wherein the fluid inlet of the gas flow path separator and the liquid flow path separator are fluidically coupled to the fluid outlet of the third fluid mover, and wherein the fluid inlet of the gas flow path separator and the liquid flow path separator are fluidically coupled to the fluid outlet of the second fluid mover through the third fluid mover and through the second fluid reservoir.

[0092] A twenty-second embodiment, which is the method of any of the nineteen through twenty-first embodiments, wherein the gas separator assembly further comprises a spider bearing concentric with the drive shaft and located within the first fluid reservoir, wherein the spider bearing comprises props that provide fluid communication paths between the props.

[0093] Although modalities have been shown and described, modifications of these can be made by someone skilled in the technique without departing from the spirit and precepts. Petition 870260045189, dated 05 / 13 / 2026, page 44 / 72 37 / 38 of this disclosure. The modalities described in this document are merely exemplary and are not intended to be limiting. Many variations and modifications of the modalities disclosed herein are possible and are within the scope of this disclosure. When numerical ranges or limitations are expressly stated, such ranges or limitations should be understood as including iterative ranges or limitations of equal magnitude within the explicitly expressed ranges or limitations (e.g., from about 1 to about 10 includes 2, 3, 4, etc., greater than 0.10 includes 0.11, 0.12, 0.13, etc.). For example, whenever a numerical range with a lower limit, Rl, and an upper limit, Ru, is disclosed, any number that falls within the range will be specifically disclosed.In particular, the following numbers within the range are specifically disclosed: R = Rl + k * (RuRl), where k is a variable ranging from 1 percent to 100 percent in increments of 1 percent, i.e., k is 1 percent, 2 percent, 3 percent, 4 percent, 5 percent, ... 50 percent, 51 percent, 52 percent, ...., 95 percent, 96 percent, 97 percent, 98 percent, 99 percent, or 100 percent. Furthermore, any numerical range defined by two R numbers, as defined above, is also specifically disclosed. The use of the term “optionally” in relation to any element of a claim is intended to mean that the element in question is necessary or, alternatively, is not necessary. Both alternatives are intended to be within the scope of the claim. The use of broader terms such as comprises, includes, having, etc.It should be understood as providing support for more restricted terms, such as consisting of, consisting essentially of, composed substantially of, etc.

[0094] Therefore, the scope of protection is not limited by the description set forth above, but is limited only by the claims that follow, the scope of which includes all subject matter equivalents of the claims. Each and every claim is incorporated into the descriptive report as an embodiment of this disclosure. Thus, the claims are a further description and are an addition to the embodiments of this disclosure. The discussion of a reference herein is not an admission that it is prior art, especially any reference that may have a publication date after the priority date of this patent application. Disclosures of all patents, applications and patent publications cited in this document are Petition 870260045189, dated 05 / 13 / 2026, p. 45 / 72 38 / 38 are incorporated herein by reference, insofar as they provide illustrative, procedural or other details that are supplementary to those presented herein. Petition 870260045189, dated 05 / 13 / 2026, p. 46 / 72

Claims

1 / 12 CLAIMS 1. Downhole gas separator assembly, characterized in that it comprises: a drive shaft (172); a first fluid mover (405A, 405B) mechanically coupled to the drive shaft and having a fluid inlet and a fluid outlet;a fluid reservoir (170) arranged concentrically around the drive shaft and located downstream of the first fluid mover, wherein an inner surface of the fluid reservoir and an outer surface of the drive shaft define a first annular space within a portion of the fluid reservoir that does not enclose a radial support of the drive shaft, wherein the first annular space is fluidically coupled to the fluid outlet of the first fluid mover, wherein, when the separator drive shaft is about 0.6875 inches (17.45 mm) in diameter, the first annular space has a volume of at least 73.999 cubic inches (0.0012126 m3) and less than 111.00 cubic inches (0.00182 m3);Whereas, when the separator drive shaft is about 0.875 inches (22.2 mm) in diameter, the first annular space has a volume of at least 90.198 cubic inches (0.0014781 cubic meters) and less than 126.28 cubic inches (0.0020694 cubic meters); whereas when the separator drive shaft is about 1.0 inch (35.4 mm) in diameter, the first annular space has a volume of at least 170.85 cubic inches (0.0027997 cubic meters) and less than 239.19 cubic inches (0.0039196 cubic meters); and whereby, when the separator drive shaft is approximately 1.1875 inches (30.163 mm) in diameter, the first annular space has a volume of at least 167.63 cubic inches (0.0027467 cubic meters) and less than 234.68 cubic inches (0.0038457 cubic meters);a second fluid mover (302) having a fluid inlet and a fluid outlet, wherein the second fluid mover is located downstream of the fluid reservoir, and wherein the fluid inlet of the second fluid mover is fluidically coupled to the first annular space; a separation chamber (303) arranged concentrically around the drive shaft and located downstream of the second fluid mover, wherein an inner surface of the separation chamber and the outer surface of the drive shaft define a second annular space that is fluidically coupled to the fluid outlet of the second fluid mover;and a separator of the gas flow path and the liquid flow path (350) having a gas phase discharge orifice (138) open to an exterior of the assembly and a liquid phase discharge orifice, wherein the separator of the gas flow path and the liquid flow path has a fluid inlet that is fluidically coupled to the second annular space.; 2. Well bottom gas separator assembly, according to claim 1, characterized in that a distance between the fluid inlet (136) of the first fluid mover (405A, 405B) and the gas phase discharge orifice (138) of the separator of the gas flow path and liquid flow path (350) is at least 4 feet (1.2192 m) and less than 500 feet (152.4 m).

3. Downhole gas separator assembly, according to claim 1, characterized in that it further comprises a spider bearing (184) located within the fluid reservoir (170) having a central through hole surrounding the drive shaft (172).

4. Downhole gas separator assembly, according to claim 1, characterized in that it further comprises a housing (312), wherein the inner surface of the fluid reservoir (170) and the inner surface of the separation chamber (303) are provided by an inner surface of the housing, wherein the first fluid mover (405A, 405B) and the second fluid mover (302) are located within the housing, and wherein the separator of the gas flow path and the liquid flow path (350) is mechanically coupled to the housing.

5. Downhole gas separator assembly, according to claim 1, characterized in that it further comprises a housing (312), wherein the inner surface of the separation chamber (303) is provided by an inner surface of the housing, wherein the inner surface of the fluid reservoir (170) is provided by a sleeve (322) which is retained within the housing, wherein the first fluid mover (405A, 405B) and the second fluid mover (302) are located within the housing, and wherein the separator of the gas flow path and the liquid flow path (350) is mechanically coupled to the housing.

6. Well bottom gas separator assembly, according to claim 1, characterized in that the second fluid mover (302) is a stationary auger, an auger mechanically coupled to the drive shaft (172), an impeller mechanically coupled to the drive shaft, a centrifugal rotor mechanically coupled to the drive shaft, or a paddle wheel mechanically coupled to the drive shaft.

7. Downhole gas separator assembly according to claim 1, characterized in that the first fluid mover (405A, 405B) is a centrifugal pump having at least one centrifugal pump stage wherein each centrifugal pump stage comprises an impeller mechanically coupled to the drive shaft (172) and a diffuser (408).

8. Downhole gas separator assembly, according to claim 1, characterized in that the second fluid mover (302) is mechanically coupled to the drive shaft (172) and further comprises: a second fluid reservoir (174) arranged concentrically around the drive shaft and located downstream of the second fluid mover, wherein an inner surface of the second fluid reservoir and an outer surface of the drive shaft define a third annular space that is fluidically coupled to the fluid outlet of the second fluid mover;and a third fluid mover (415A) having a fluid inlet and a fluid outlet, wherein the third fluid mover is located downstream of the second fluid reservoir and is located upstream of the separation chamber (303), wherein the fluid inlet of the third fluid mover is fluidically coupled to the third annular space, and wherein the fluid outlet of the third fluid mover is fluidically coupled to the second annular space.

9. Downhole gas separator assembly according to claim 8, characterized in that it further comprises: a base (403) having an inlet (136); a fourth fluid mover (415B) mechanically coupled to the drive shaft (172), located upstream of the base, having a fluid outlet and having a fluid inlet fluidically coupled to the base inlet; a third fluid reservoir (176) arranged concentrically around the drive shaft (172) and located downstream of the fourth fluid mover, wherein an inner surface of the third fluid reservoir and the outer surface of the drive shaft define a fourth annular space that is fluidically coupled to the fluid outlet of the fourth fluid mover;a fifth fluid mover (425A) having a fluid inlet and a fluid outlet, wherein the fifth fluid mover is located downstream of the third fluid reservoir, and wherein the fluid inlet of the fifth fluid mover is fluidically coupled to the fourth annular space; a second separation chamber (303B) arranged concentrically around the drive shaft and located downstream of the fifth fluid mover, wherein an inner surface of the second separation chamber and the outer surface of the drive shaft define a fifth annular space that is fluidically coupled to the fluid outlet of the fifth fluid mover;and a second separator of the gas flow path and the liquid flow path having a gas phase discharge orifice open to an exterior of the assembly and a liquid phase discharge orifice (138) fluidically coupled to the fluid inlet (136) of the first fluid mover (405A, 405B) and WHEREAS the separator of the gas flow path and the liquid flow path (350) has a fluid inlet fluidically coupled to the fifth annular space.; 10. Method for lifting liquid in a wellbore, characterized in that it comprises: passing an electric submersible pump (ESP) assembly (132) into a wellbore, the ESP assembly comprising an electric motor (122), a gas separator assembly (126) having a fluid inlet (136) and a liquid phase discharge orifice (316) and a centrifugal pump assembly (128) having a fluid inlet fluidically coupled to the liquid discharge orifice of the gas separator assembly; rotating a drive shaft (172) of the gas separator assembly by an electric motor of the ESP assembly; extracting reservoir fluid from the wellbore into the gas separator assembly by a first fluid mover (405A, 405B) of the gas separator assembly which is coupled to the drive shaft; moving the reservoir fluid downstream by the first fluid mover within the gas separator assembly;to fill an annular space within the gas separator assembly with fluid from the reservoir, wherein the annular space is defined between an inner surface of the gas separator assembly and an outer surface of the drive shaft within Petition 870260045189, dated 05 / 13 / 2026, page 52 / 72 7 / 12 of a portion of the fluid reservoir that does not enclose a radial support of the drive shaft, wherein, when the separator drive shaft is about 0.6875 inches (17.45 mm) in diameter, the first annular space has a volume of at least 73.999 cubic inches (0.0012126 m3) and less than 111.00 cubic inches (0.00182 m3); whereby, when the separator drive shaft is about 0.875 inches (22.2 mm) in diameter, the first annular space has a volume of at least 90.198 cubic inches (0.0014781 cubic meters) and less than 126.28 cubic inches (0.0020694 cubic meters);wherein, when the separator drive shaft is about 1.0 inch (35.4 mm) in diameter, the first annular space has a volume of at least 170.85 cubic inches (0.0027997 cubic meters) and less than 239.19 cubic inches (0.0039196 cubic meters); and wherein, when the separator drive shaft is about 1.1875 inches (30.163 mm) in diameter, the first annular space has a volume of at least 167.63 cubic inches (0.0027467 cubic meters) and less than 234.68 cubic inches (0.0038457 cubic meters), and wherein the annular space is located downstream of the first fluid mover; to drain the reservoir fluid from the annular space within the gas separator assembly to a second fluid mover (302) of the gas separator, wherein the second fluid mover is located downstream of the annular space;move the fluid from the downstream reservoir by the second fluid mover to a gas flow path separator and liquid flow path separator (350) of the gas separator assembly; Petition 870260045189, dated 05 / 13 / 2026, page 53 / 72 8 / 12 discharge a portion of the reservoir fluid through a gas phase discharge port (138) of the gas flow path separator and liquid flow path separator to an exterior of the gas separator assembly; discharge a portion of the reservoir fluid through a liquid phase discharge port of the gas flow path separator and liquid flow path downstream of the gas separator assembly to the centrifugal pump assembly; pump the discharged reservoir fluid portion through the liquid phase discharge port by the centrifugal pump assembly;and drain the portion of the reservoir fluid discharged through the liquid phase discharge orifice out of a centrifugal pump assembly discharge through a production pipeline to a surface location.

11. Method according to claim 10, characterized in that it further comprises: extracting gas from the wellbore (102) to the gas separator (126) by the first fluid mover (405A, 405B); flowing the gas downstream by the first fluid mover within the gas separator assembly; mixing the gas with reservoir fluid retained by the annular space to form a gas and fluid mixture; and flowing the gas and fluid mixture from the annular space within the gas separator assembly to the second fluid mover (302) of the gas separator assembly.

12. Method according to claim 10, characterized in that it further comprises stabilizing the drive shaft (172) by a plurality of spider bearings Petition 870260045189, dated 05 / 13 / 2026, page 54 / 72 9 / 12 (184), wherein each spider bearing is concentric with the drive shaft, is located within the annular space within the gas separator assembly (126) and provides flow paths for reservoir fluid between spider bearing struts (188).

13. A method for mounting an electric submersible pump assembly, in a wellbore location (102), characterized in that it comprises: coupling a downstream end of an electric motor (122) to an upstream end of a sealing unit (124); lowering the electric motor and the sealing unit partially into the wellbore; coupling a downstream end of the sealing unit to an upstream end of a gas separator assembly (126), wherein the gas separator assembly comprises: a drive shaft (172), a first fluid mover (405A, 405B) mechanically coupled to the drive shaft and having a fluid inlet (136) and a fluid outlet;a fluid reservoir (170) arranged concentrically around the drive shaft and located downstream of the first fluid mover, wherein an inner surface of the fluid reservoir and an outer surface of the drive shaft define a first annular space within a portion of the fluid reservoir that does not enclose a radial support of the drive shaft, wherein the first annular space is fluidically coupled to the fluid outlet of the first fluid mover, wherein when the separator drive shaft is about 0.6875 inches (17.45 mm) in diameter, the first annular space has a volume of Petition 870260045189, dated 05 / 13 / 2026, page 55 / 72 10 / 12 at least 73.999 cubic inches (0.0012126 m3) and less than 111.00 cubic inches (0.00182 m3);Whereas, when the separator drive shaft is about 0.875 inches (22.2 mm) in diameter, the first annular space has a volume of at least 90.198 cubic inches (0.0014781 cubic meters) and less than 126.28 cubic inches (0.0020694 cubic meters); whereas when the separator drive shaft is about 1.0 inch (35.4 mm) in diameter, the first annular space has a volume of at least 170.85 cubic inches (0.0027997 cubic meters) and less than 239.19 cubic inches (0.0039196 cubic meters); and whereby, when the separator drive shaft is about 1.1875 inches (30.163 mm) in diameter, the first annular space has a volume of at least 167.63 cubic inches (0.0027467 cubic meters) and less than 234.68 cubic inches (0.0038457 cubic meters);a second fluid mover (302) having a fluid inlet and a fluid outlet, wherein the second fluid mover is located downstream of the fluid reservoir, and wherein the fluid inlet of the second fluid mover is fluidically coupled to the first annular space; a separation chamber (303) arranged concentrically around the drive shaft and located downstream of the second fluid mover, wherein an inner surface of the separation chamber and the outer surface of the drive shaft define a second annular space that is fluidically coupled to the fluid outlet of the second fluid mover;and a gas flow path separator and liquid flow path Petition 870260045189, dated 05 / 13 / 2026, page 56 / 72 11 / 12 (350) having a gas phase discharge orifice (138) open to an exterior of the assembly and a liquid phase discharge orifice (316), wherein the gas flow path separator and liquid flow path separator has a fluid inlet that is fluidically coupled to the second annular space; lower the electric motor, the sealing unit and the gas separator assembly partially into the wellbore; couple a downstream end of the gas separator assembly to an upstream end of the centrifugal pump assembly; and lower the electric motor, the sealing unit, the gas separator assembly and the centrifugal pump assembly partially into the wellbore.

14. Method according to claim 13, characterized in that the gas separator assembly (126) comprises a plurality of fluid reservoirs (170, 174, 176).

15. Method according to claim 13, characterized in that the second fluid mover (302) is mechanically coupled to the drive shaft (172) and the gas separator assembly (126) comprises: a second fluid reservoir (174) arranged concentrically around the drive shaft and located downstream of the second fluid mover, wherein an inner surface of the second fluid reservoir and an outer surface of the drive shaft define a second annular space that is fluidically coupled to the fluid outlet of the second fluid mover; and a third fluid mover having a fluid inlet and a fluid outlet, wherein the third Petition 870260045189, dated 05 / 13 / 2026, p.57 / 72 12 / 12 fluid mover is located downstream of the second fluid reservoir and the fluid inlet of the third fluid reservoir is fluidically coupled to the second fluid reservoir, the gas flow path separator and the liquid flow path separator (350) is located downstream of the third fluid mover, the fluid inlet of the gas flow path separator and the liquid flow path separator are fluidically coupled to the fluid outlet of the third fluid mover, and the fluid inlet of the gas flow path separator and the liquid flow path separator is fluidically coupled to the fluid outlet of the second fluid mover through the third fluid mover and through the second fluid reservoir. Petition 870260045189, dated 05 / 13 / 2026, p. 58 / 72.

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