Hydraulically actuated double acting positive displacement pump system for producing fluid from wellbore

Abstract

A downhole pumping system for subsea use is provided. The pumping system is designed such that all fluid conduits and electrical signal conduits are internalized within the pumping assembly. This design provides a substantially constant and elongated profile for the pumping assembly. The pumping assembly includes a housing containing the power assembly, a power actuator assembly operably linked to the production fluid assembly, and a central bore extending through the pumping assembly to provide fluid communication between the power assembly and a first end of the pumping assembly. The pumping system also includes a flow distributor / connector at the first end or the pump head for providing fluid communication between the pump head and a delivery system extending from the surface to the pumping system. The communicating fluids include a high pressure power hydraulic fluid, a low pressure discharge hydraulic fluid, and a pressurized production wellbore fluid.

Description

Technical Field

[0001] The present disclosure relates to downhole pumps for delivering fluids from a surface into a wellbore and to devices and systems for delivering the fluids from the pump back to the surface. Specifically, embodiments of the present disclosure include a slender-profile pumping system sized for various sizes of wellbores. Background Art

[0002] It is known to use a reciprocating linear pump installed in a straight line at the bottom end of a wellbore, attach a pipe between the pump and surface collection equipment, and provide power to the reciprocating motion of the pump, typically to the reciprocating motion of a piston disposed within a cylinder having associated flow valve controls, such as check valves, to control fluid flow within the pump subassembly; provide the reciprocating linear motion from the surface to the pump subassembly under power through a series of sucker rods connected end-to-end, with the lowermost end attached to the pump subassembly and the uppermost end attached to some mechanism, such as a pump-jack or similar drive mechanism. The linear pump can be a series or multi-stage lift piston and packer, with appropriate check valves at each stage. These systems are time-tested and provide high reliability, but in practice, these systems cannot be deployed in deviated wellbores because a series of rigidly interconnected rods cannot linearly move around corners or bends in a deviated wellbore (commonly referred to as a 'horizontal well') without impacting the inner wall of the well, resulting in damage and wear to the housing and rod system. Additionally, the pump-jack type lift system provides a very uneven pressure distribution of the produced fluid and a relatively low and uneven flow rate, resulting in a lower pumping volume and low efficiency. These pumps are very common and form part of the common general knowledge within the field of the present invention.

[0003] A known solution for delivering produced fluids from a horizontal well is to use a relatively flexible fluid pipe fluidly connected to an electric submersible pump (ESP). Known ESPs can have various externally connected fluid pipes and electrical conductors to deliver the fluid and electrical command signals to where they must be delivered to achieve proper functioning. Summary of the Invention

[0004] Without being bound by any particular theory, embodiments of the present disclosure relate to a pumping assembly in which all relevant fluid conduits are in fluid communication with associated sub-assemblies along a longitudinal axis of the assembly. The fluid conduits are located inside an outer surface of the pumping assembly. Additionally, embodiments of the present disclosure provide an internalized electrical conductor that enters one end of the pumping assembly and extends generally along the longitudinal axis of the pumping assembly to deliver (and receive) electrical signals to a power assembly at the downhole end of the pumping assembly. The in-line and internal fluid conduits and the internal electrical conductor allow the outer surface of the pumping assembly to have a generally constant outer diameter along its length and to have a generally smooth outer profile. Without being bound by any particular theory, the generally constant outer diameter and smooth outer profile may allow the pumping assembly to have a smaller cross-sectional area such that it can be used in smaller wellbores where known pumps may not fit.

[0005] Some embodiments of the present disclosure relate to a downhole pumping assembly. The pumping assembly includes a first end and a second end, with an outer surface defined therebetween that has a generally constant outer diameter. The pumping assembly further includes: a power assembly near the second end and configured to direct power fluid; and a production fluid assembly near the first end and configured to receive wellbore fluid, the production fluid assembly including a production piston configured to direct the received wellbore fluid toward the first end. The pumping assembly further includes: a power actuation assembly positioned adjacent to and in fluid communication with the power assembly, the power actuation assembly operably coupled to the production fluid assembly and configured to receive power fluid and move the production piston via the operable coupling to direct the received wellbore fluid toward the first end; and a central conduit extending from the first end to the power assembly to conduct power fluid therebetween.

[0006] Some embodiments of the present disclosure relate to a connector, also referred to herein as a flow diverter. The connector has a first end connectable to a fluid conducting system and a second end connectable to a pumping assembly. The connector further includes an internal fluid passage in fluid communication with a first fluid conduit, a second fluid conduit, and a third fluid conduit. The internal fluid passage conveys fluid contents of the first fluid conduit to exit the second end from a generally centered position relative to the body of the connector. The connector is also configured to provide one or more internal conductor channels to allow one or more electrical conductors to extend therethrough.

[0007] Some embodiments of the present disclosure relate to a system that includes a subterranean fluid delivery system for directing motive fluid to a connector and for directing effluent fluid from the connector to the surface. The system also includes a connector through which motive fluid, effluent fluid, and production fluid are directed. The system also includes a pumping assembly fluidly connectable to the connector at a first end. The pumping assembly includes a power actuator assembly and a power assembly at an opposite end of the first end. The power actuator assembly is in fluid communication with the power assembly for moving a power piston of the power actuator assembly. The pumping assembly also includes a production fluid piston operably linked to the power piston. The pumping assembly also includes a central conduit extending from the first end to the power assembly, the central bore configured to receive motive fluid from the fluid delivery system for delivery to the power assembly.

[0008] In some embodiments of the present disclosure, the fluid delivery system is configured to accommodate one or more electrical conductors that may extend from the surface to the connector. In some embodiments of the system, the fluid delivery system includes a conduit for delivering production fluid received from the connector to a wellhead above. The fluid delivery system also includes a set of two conduits, one conduit positioned within the other, the set of two conduits configured to be fluidly connected to the central conduit of the pumping assembly. The set of two conduits is also configured to deliver motive fluid to the central conduit and to receive effluent fluid from the central conduit. In these embodiments, the connector defines an internal fluid flow channel system configured to direct appropriate fluid from the pumping assembly to the appropriate fluid conduits of the fluid delivery system.

[0009] In some embodiments of the present disclosure, the fluid delivery system includes three fluid conduits, wherein a first conduit is positioned within a second conduit, and the second conduit is positioned within a third conduit. One of the three conduits is configured to deliver motive fluid from the surface to the connector. Another of the three conduits is configured to deliver effluent fluid from the connector to the surface above. Another of the three conduits is configured to deliver production fluid from the connector to the surface above. In these embodiments, the connector defines an internal fluid flow channel system configured to direct appropriate fluid from the pumping assembly to the appropriate fluid conduits of the fluid delivery system.

[0010] In some embodiments of the present disclosure, the fluid delivery system includes two sets of fluid conduits, where each set has a first conduit positioned within a second conduit. The outer conduit of each set can deliver production fluid from the connector to the surface. The inner conduit of one set can deliver power fluid from the surface to the connector, while the inner conduit of the other set can deliver effluent fluid from the connector to the surface. In these embodiments, the connector defines an internal fluid flow channel system that is configured to direct appropriate fluids from the pumping assembly to the appropriate fluid conduits of the fluid delivery system.

[0011] In some embodiments of the present disclosure, the fluid delivery system includes two fluid conduits, one fluid conduit positioned within the other. The inner fluid conduit is configured to deliver power fluid from the surface to the connector, and the outer conduit is configured to deliver effluent fluid from the connector to the surface. In these embodiments, the connector defines an internal fluid flow channel system that is configured to direct appropriate fluids from the pumping assembly to the appropriate fluid conduits of the fluid delivery system. In these embodiments, the connector is configured to sealingly engage the inner surface of the wellbore such that production fluid can be delivered to the surface through the wellbore.

[0012] Some embodiments of the present disclosure relate to a fluid delivery system for providing fluid communication between a surface system of a device and a downhole pumping assembly. The fluid delivery system includes: a first end and a second end that define an outer surface therebetween, the first end being connectable to the surface system of the device; one or more inner fluid conduits for providing fluid communication between the first end and the second end; and a connector that is connected to the second end for operably coupling the one or more inner fluid conduits to the downhole pumping assembly, the connector including a central channel, a secondary channel, and a production fluid channel.

[0013] Some embodiments of the present disclosure relate to a downhole pumping assembly. The assembly includes: a first end and a second end, defining an outer surface therebetween, the outer surface having a substantially constant outer diameter; a power assembly, proximate to the second end and configured to direct a power fluid; a production fluid assembly, proximate to the first end and configured to receive wellbore fluid, and including a production piston configured to direct the received wellbore fluid toward the first end; a power actuation assembly, positioned adjacent to the power assembly and in fluid communication therewith, the power actuation assembly operably coupled to the production fluid assembly, the power actuation assembly configured to receive the power fluid and move the production piston via the operable coupling to direct the received wellbore fluid toward the first end, wherein the power assembly includes a switchable valve for directing the power fluid to a first face or a second face of a power piston of the power actuation assembly and includes a check valve, the check valve normally closed during normal operation of the pumping assembly, but openable when the downhole pump stops operating and / or by reverse fluid flow. In some embodiments of the present disclosure, the check valve can be actuated between a first position and a second position, when in the first position, the check valve is closed, and when in the second position, the check valve can be opened by the power fluid to reverse the flow direction of the power fluid through the power assembly, or stop the operation of the power assembly and thus the pumping assembly.

[0014] Some embodiments of the present disclosure relate to a method 700 for reversing the direction of fluid flow through a system. Method 700 can be used by various systems described above, such as a system for operating a pumping system. Method 700 includes the steps of: establishing 702 a flow of a first fluid in a first direction between a first fluid source and a power assembly, wherein the power assembly distributes the first fluid for operating the pumping system; establishing 704 a flow of a second fluid in a second direction opposite to the first direction between the power assembly and a second fluid source, wherein the pressure of the second fluid is lower than the pressure of the first fluid; and reversing 706 the flow in the first direction to the second direction.

[0015] In some embodiments of the present disclosure, the fluid delivery system includes three separate fluid conduits, one for delivering a power fluid to a connector, one for delivering a discharge fluid from the connector to the surface, and another for delivering a production fluid from the connector to the surface.

[0016] Without being bound by any particular theory, the fluid delivery system described herein allows for the assembly of various conduits in a proper relative arrangement prior to deployment at a well site. This can allow for cost and time savings at the well site.

[0017] Without being bound by any particular theory, the systems and methods described herein for reversing the direction of flow of hydraulic fluid can allow the hydraulic fluid to flow substantially continuously or continuously through the power section of a downhole pumping assembly. This substantially continuous or continuous flow can protect the components of the downhole pumping system by keeping the temperature of the hydraulic and electronic components within their operating temperature limits. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In the following detailed description made with reference to the accompanying drawings, the features of the present disclosure will become more apparent.

[0019] Figure 1 is a schematic view depicting a system according to an embodiment of the present disclosure, the system being configured to deliver fluid from a surface to a well and to a downhole pump, and to deliver fluid from the pump back to the surface.

[0020] Figure 2 is a depiction of Figure 1 the operation of the pumping assembly of the system in Figure 2 A showing a piston moving in a first direction; and Figure 2 B showing the same piston moving in the opposite direction under a different rotational view from Figure 2 A.

[0021] Figure 3 is a schematic view depicting a valve assembly, where Figure 3 A shows the operating position of the valve assembly according to the operation depicted in Figure 2 A; and Figure 3 B shows the operating position of the valve assembly according to the operation depicted in Figure 2 B.

[0022] Figure 4 is a more detailed schematic view depicting the system of Figure 1 .

[0023] Figure 5 shows Figure 4 a variation of the system depicted in

[0024] Figure 6 shows in more detail the components of the system depicted in Figure 4 , where Figure 6 A shows the fluid delivery system and surface equipment; and Figure 6 B shows the connector.

[0025] Figure 7 shows Figure 4 a variation of the system depicted in

[0026] Figure 8 shows in more detail Figure 7The components of the system depicted in, where Figure 8 A shows a fluid delivery system and a surface device; and Figure 8 B shows a connector.

[0027] Figure 9 shows Figure 4 a variant of the system depicted in.

[0028] Figure 10 Shows in more detail Figure 9 the components of the system depicted in, where Figure 10 A shows a fluid delivery system and a surface device; and Figure 10 B shows a connector.

[0029] Figure 11 shows Figure 4 a variant of the system depicted in.

[0030] Figure 12 Shows in more detail Figure 11 the components of the system depicted in, where Figure 12 A shows a fluid delivery system and a surface device; and Figure 12 B shows a connector.

[0031] Figure 13 shows Figure 4 a variant of the system depicted in.

[0032] Figure 14 Shows in more detail Figure 13 the components of the system depicted in, where Figure 14 A shows a fluid delivery system and a surface device; and Figure 14 B shows a connector.

[0033] Figure 13 shows Figure 4 a variant of the system depicted in.

[0034] Figure 14 Shows in more detail Figure 13 the components of the system depicted in, where Figure 14 A shows a fluid delivery system and a surface device; and Figure 14 B shows a connector.

[0035] Figure 15 shows Figure 4 a variant of the system depicted in.

[0036] Figure 16 Shows in more detail Figure 15 the components of the system depicted in, where Figure 16 A shows a fluid delivery system and a surface device; and Figure 16B shows a connector.

[0037] Figure 17 shows Figure 4 a variation of the system depicted in

[0038] Figure 18 shows in more detail Figure 17 the components of the system depicted in Figure 18 wherein A shows a fluid delivery system and surface equipment; and Figure 18 B shows a connector.

[0039] Figure 19 shows a schematic diagram of a system according to an embodiment of the present disclosure.

[0040] Figure 20 shows Figure 19 a more detailed view of the system of

[0041] Figure 21 shows a schematic diagram of a system according to an embodiment of the present disclosure. Detailed Description

[0042] Unless otherwise defined, all technical and scientific terms used herein have the meaning commonly understood by one of ordinary skill in the art in the context of the present disclosure. Although any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the present disclosure, the preferred methods and materials are now described. Any publications mentioned herein are incorporated herein by reference in their entirety.

[0043] Embodiments of the present disclosure relate to a downhole and thus submersible pumping system for delivering produced fluids in a wellbore from a subterranean zone to surface equipment. Embodiments of the present disclosure relate to a pumping system having a pumping assembly that includes an outer housing and is designed to house all functional and delivery components of the pumping assembly. Without being bound by any particular theory, the housing of the functional and delivery components of the pumping assembly allows the outer diameter of the outer surface of the outer housing to be smaller than the outer diameters of other downhole pumping assemblies. The housing of the functional and delivery components of the pumping assembly can also allow the outer housing to have a substantially constant outer profile. The small outer diameter and / or substantially constant outer profile can allow the pumping system to be used in a wellbore having an inner diameter of about 5.5 inches (one inch is about 2.54 cm) or greater.

[0044] Figure 1FIG. 0 is a non - limiting schematic diagram of a pumping system 600 according to an embodiment of the present disclosure. System 600 includes an above - ground system 602 of the device and an underground system 604 of the device. The above - ground system 602 includes a hydraulic station 300 and a controller system 400. The hydraulic station 300 includes a hydraulic tank 85 for containing a certain volume of hydraulic fluid 80. A primary hydraulic displacement pump 40 is in fluid communication with the tank 85 for sucking and pressurizing the hydraulic fluid 80 into a power fluid 55, and the power fluid can flow through a first flow meter 50 and / or a second flow meter 35 before entering a power pipeline 56. The power pipeline 56 contains the pressurized power fluid 55 that can power one or more components of the underground system 604. The hydraulic station 300 can receive a return pipeline 66 that contains a low - pressure discharge fluid 65 that has returned from the underground system 604. The return pipeline 66 is in fluid communication with the tank 85, and the discharge fluid can pass through a hydraulic fluid cooling device 70 and / or a filter 75 before entering the tank 85.

[0045] The controller system 400 can be operably connected to one or more components of the hydraulic station 300. For example, the controller 400 can include a computerized programmable logic controller (PLC) 402. The PLC 402 can include a display and a flow meter module 35A for controlling the flow rate of the power fluid 55 by controlling the flow meter 35. The PLC 402 can also include a pressure control system (P / T) 40A configured to control the pressure of the power fluid 55 by controlling the activity of the primary hydraulic displacement pump 40. The PLC 402 can also include a temperature control system (T / T) 70 for controlling the temperature of the fluid 80 in the tank 85 via one or more temperature sensors and heating elements (not shown). The tank 85 can also be used to cool the hot low - pressure discharged hydraulic fluid received from the underground system 604 of the device. While the heating feature of the tank 85 is necessary when the system 600 is located in a cold climate, the cooling feature of the tank 85 is applicable when the system 600 is used to produce a production fluid from an underground reservoir that is exposed to high temperatures to reduce the viscosity of the production fluid. For example, the underground reservoir can be heated by undergoing one or more thermal activity processes, such as high - temperature steam assisted gravity drainage (SAGD) operations, high - temperature solvent operations, downhole combustion operations, combinations thereof, etc. The PLC 402 can also include a variable frequency drive (VFD) 36A for controlling the activity of the primary hydraulic displacement pump 40 and another VFD 70A for controlling the cooling device 70.

[0046] The PLC 402 may also include one or more solenoid controllers 31A and 32B and one or more limit switch controllers 33A and 34A. Commands in the form of electrical signals from controllers 31A, 32A, 33A, and 34A may be transmitted via the conductive system 608 to the downhole equipment. As will be understood by those skilled in the art, the conductive system 608 may be protected from the harsh environment present within the wellbore in order to provide effective communication of commands from controllers 31A, 32A, 33A, and 34A to the downhole equipment.

[0047] The PLC 402 may be configured to coordinate the delivery of the power fluid 55 via the conduit 56 at a desired pressure and temperature and the movement of one or more components of the downhole equipment 604 via controllers 31A, 32B, 33A, and 34A. As will be understood by those skilled in the art, the PLC 402 may be pre-programmed to perform this coordination and / or it may respond to commands input by a user.

[0048] The surface system 602 may also include a wellhead system 200 that includes a wellhead 20 configured to receive conduits 55 and 65, conductors of the conductive system 608, and a production fluid outlet 25. Among other functions, the wellhead system 200 is configured to provide pressure control of the fluid within the wellbore 15 of the downhole system 604. The wellbore 15 may be lined, cased, cemented, or unlined, uncased, uncemented, and the wellbore 15 is configured to receive produced fluid, such as a multiphase flow of solids, gases, and liquids, from an underground reservoir adjacent thereto. The reservoir may be stimulated by hydraulic fracturing, thermal stimulation (such as cyclic steam stimulation, steam-assisted gravity drainage, heated solvent stimulation), chemical stimulation (such as solvent stimulation), etc.

[0049] The downhole system 604 may include a pumping assembly 500 and a fluid delivery system 606 extending from the pumping assembly 500 to the wellhead 20. The fluid delivery system 606 provides one or more conduits that transport the power fluid 55 from the conduit 56 to the pumping assembly 500 and transport the effluent fluid 65 from the pumping assembly 500 to the conduit 66. In some embodiments of the present disclosure, the fluid delivery system 606 may also provide an optional production conduit 10 for transporting production fluid to the production fluid outlet 25. In some embodiments of the present disclosure, the fluid delivery system 606 may also provide a conduit for extending the conductive system 608 from the wellhead 20 to the pumping assembly 500.

[0050] The pumping assembly 500 is configured to be positioned within an oil well and / or a gas well and receive produced fluid. The pumping assembly 500 is configured to pressurize the received produced fluid (at Figure 2The received production fluid 23 shown as unpressurized and the received production fluid 25 shown as pressurized) and delivers it to the production fluid outlet 25 of the wellhead system 200. The pumping assembly 500 has a first end 500A and a second end 500B for defining the longitudinal axis of the pumping assembly 500 (represented by line α in Figure 1 ). As will be understood by those skilled in the art, the first end 500A is closer to the wellhead 20 and, therefore, it may also be referred to as the well upper end. The second end 500B is farther from the wellhead 20 and, therefore, it may also be referred to as the well lower end. The term "uphole" can be used herein to refer to the end or the direction orientation of a component within the well that is towards the wellhead 20. The term "downhole" can be used herein to refer to a component within the well or the direction orientation that is away from the wellhead 20.

[0051] In some embodiments of the present disclosure, the pumping assembly 500 includes three main components: a power assembly 502, a power actuator assembly 504, and a production fluid assembly 506. The pumping assembly 500 further includes a central pipe 508 that extends from the first end 500A through the production fluid assembly 506 and the power actuator assembly 504 to the power assembly 502. The central pipe 508 may be centrally located within the cross-sectional area of the pumping assembly 500, or in some embodiments, it may be non-centrally located. The central pipe 508 is configured to provide fluid communication between the well lower end of the fluid delivery system 606 and the power assembly 502 via a connector 170 (which is also referred to as a flow diverter).

[0052] The power assembly 502 is configured to receive the power fluid 55 from the pipe 56 via the central pipe 508. The power assembly is also configured to direct the power fluid 55 to the power actuator assembly 504 for moving the power piston 112 therein. The power piston 112 is operatively coupled to the production piston 135 by a link member 520 (see Figure 2 ), such that if the power piston 112 moves in a first direction, the production piston 135 will move in the same direction by the same stroke distance. If the power piston 112 moves in an opposite second direction, the production piston 135 will also move in the second direction and by the same stroke distance as the power piston 112 moves.

[0053] As will be discussed further below, the pumping assembly 500 may also include a connector 170 connectable to the first end 500A of the pumping assembly 500 for providing fluid communication between the downhole end of the fluid delivery system 606 and the central conduit 508. The connector 170 may also be referred to as a flow diverter. In some embodiments of the present disclosure, the connector 170 may also provide a passage for conductors of the electrical system 608 to enter the interior of the pumping assembly 500. In these embodiments, all of the fluid / piping for delivering fluid to and from the pumping assembly 500, and all of the electrical conductors for delivering electrical signals to and optionally from the pumping assembly 500 are located internal to the outer surface 500A of the pumping assembly 500. In some embodiments of the present disclosure, the main components of the pumping assembly 500, namely: the power assembly 502, the power actuator assembly 504, and the production fluid assembly 506 are all housed within an outer housing of the pumping assembly 500, and the outer housing defines an outer surface 500C. In other embodiments, each of the power assembly 502, the power actuator assembly 504, and the production fluid assembly 506 defines its own respective outer surface such that when these components are all assembled together into the pumping assembly 500, they together define the outer surface 500C.

[0054] Without being bound by any particular theory, the internalization of all of the fluid piping, electrical conduit, and all other components of the pumping assembly 500 within the outer surface 500C provides a substantially constant outer profile of the pumping assembly 500. Additionally, this internalized design allows the outer diameter of the pumping assembly 500 to be constructed to be less than the outer diameters of other known downhole submersible pumping systems. In some embodiments of the present disclosure, the outer diameter of the pumping assembly 500 may be substantially constant along its length from the first end 500A to the second end 500B. In some embodiments of the present disclosure, the outer diameter of the pumping assembly 500 may be constructed such that the outer surface 500C is substantially free of any protrusions such that the profile of the pumping assembly 500 may be referred to as a "smooth profile".

[0055] Figure 2 A non-limiting schematic illustration of the functions and fluid flow within the pumping assembly during operation of the pumping assembly 500 is provided.

[0056] The power assembly 502 includes an outer wall 63 which may or may not form part of the outer housing of the pumping assembly 500, but the outer wall 63 contributes to defining at least a portion of the outer surface 500C. The outer wall 63 defines an internal plenum 81 which serves as a reservoir for holding the discharged fluid 65 at a lower pressure. The internal plenum 81 also houses a switchable valve 60.

[0057] Hydraulic power is provided to the pumping assembly 500 by delivering pressurized power fluid 55 from the surface via conduit 56 and fluid delivery system 606 to central conduit 508. The power fluid 55 flows through the length of the pumping assembly 500 to the power assembly 502, where the power fluid is directed to either the first face 112A or the second face 112B of the power piston 112. The lower-pressure discharge fluid 65 returns to the internal gas chamber 81, enters the central conduit 508 from the internal gas chamber, so as to return to the discharge conduit 66 via the fluid delivery system 606, and returns to the hydraulic station 300. In summary, the power fluid 55 flows via conduit 56 to and from the surface and to the pumping assembly 500 in a closed-loop system, then flows through the fluid delivery system 606, and then through the central conduit 508 to the valve 60. Movement of the valve 60 between its operating positions will direct the power fluid 55 to either the first face 112A or the second face 112B of the power piston 112. The power fluid 65 is directed from the opposite face of the power piston 112 that the power fluid 55 acts on to flow through the valve 60, and thus return via the central conduit 508, as described above. In a closed system, the power fluid 55 can be at a pressure higher than the surrounding wellbore pressure inside the power actuator assembly 504, which can help with lubrication and establish a pressure isolation effect to keep wellbore fluids and contaminants from contaminating the moving parts of the power actuator assembly 504. In some embodiments of the present disclosure, the pressure of the power fluid 55 inside the power actuator assembly 504 can be at least twice the surrounding wellbore pressure.

[0058] As Figure 2 shown in A, the central conduit 508 includes an internal conduit 510 that is coaxial with and extends along the length of the central conduit 508. The internal conduit 510 is configured to receive the power fluid 55 from the fluid delivery system 606 and deliver the power fluid 55 to the valve 60. Between the wall of the central conduit 508 and the internal conduit 510 is an annular space that is configured to receive the power fluid 65 from the internal gas chamber 81 of the power assembly 502 and deliver the power fluid 65 to the discharge conduit 66 via the fluid delivery system 606. As will be understood by those skilled in the art, the pressure of the power fluid 55 is higher than that of the power fluid 65, and thus from a material and safety perspective, it may be desirable to use the internal conduit 510 for delivering the power fluid. However, the present disclosure contemplates that the internal conduit 501 can be used for delivering the power fluid 65, and the annular space can be used for delivering the power fluid.

[0059] The power actuator assembly 504 can be housed within the outer housing of the pumping assembly 500, or it can include an outer wall 526. In the latter case, the outer wall 526 helps to define the outer surface 500C of the pumping assembly 500. An annular fluid chamber is defined between the outer wall 526 (or, as the case may be, the outer housing) and the cylinder 528, which in turn houses the power piston 112. The cylinder 528 has a first end 528A and a second end 528A, with the second end 528B being close to and in fluid communication with the power assembly 502 (see Figure 2 A). The power piston is configured to be slidably movable along the inner surface of the cylinder 528 in a first direction towards one end of the cylinder 528 and in an opposite second direction towards the other end of the cylinder 528. A suitable seal 113 can be positioned between the outer edge of the power piston 112 and the inner surface of the cylinder 528 to ensure that no fluid communication occurs across the power piston, and optionally, to facilitate the sliding movement of the power piston 112.

[0060] The valve 60 can be an electro-mechanical switching valve configured to receive power fluid 55 from the central conduit 508 via one or more extension conduits 56A to direct the flow of the power fluid 55 to the first face 112A or the second face 112B of the power piston 112, thereby causing the piston 112 to move (stroke) in the first direction or the opposite second direction, or to bypass the power actuator assembly 504 and flow only through the valve and complete a return circuit to the surface. These three valve positions can be referred to as "direct flow", "cross flow", and "bypass" or "idle". The "bypass" valve position isolates the actuator from the hydraulic fluid flow and causes the piston 112 to brake or lock in its current position, which is useful for avoiding problems that occur when moving downhole components in and out of the wellbore where pressure variations will come into play as the pumping assembly 500 moves up or down the well.

[0061] In addition, when in the "bypass" or "idle" position, the flow of hydraulic fluid from the surface to the pumping assembly 500 and back becomes relatively unobstructed, allowing for a rapid round trip of fresh hydraulic fluid (e.g., approximately 1.5 minutes per 1000 feet of travel distance), which allows the use of the hydraulic fluid as a coolant as needed to cool the pumping assembly including the valve 60.

[0062] As Figure 2As shown in FIG. A, the power fluid 55 is directed by the valve 60 along the conduit 56B to enter the power assembly 504 and act on the second face 112B of the power piston 112. Since the power piston 112 has a first face 112A and a second face 112B and can move based on the power fluid 55 acting on either of these faces, the power piston 112 can be referred to as a double-acting piston. The power piston 112 and the cylinder 528, and both are configured to accommodate an extension of the central conduit 508 therethrough. When the valve 60 is in the Figure 2 position shown in FIG. A, the power fluid 55 in the first chamber of the cylinder 528 can be on the side of the second face 112B of the power piston 112 and exist within the cylinder 528. When the power fluid 55 acts on the second face 112B, the discharge fluid 65 is directed from within the cylinder 528 into the annular fluid space to return to the valve 60 via the conduit 66B. The power fluid 65 enters the internal gas chamber 81 from the valve in order to return to the surface as described above. In Figure 2 the configuration of FIG. A, the power piston 112 can be said to move in a first direction, in this case in the uphole direction.

[0063] As Figure 2 shown in FIG. B, the power fluid 55 is directed by the valve 60 into the conduit 56B and moves through the annular fluid space and then into the cylinder 528 to act on the first face 112A of the power piston 112. Since the valve 60 opens the discharge port, the fluid on the opposite side of the power piston 112 has lost its pressure. When the power piston 112 moves in a second direction (in this case the downhole direction), the power fluid 65 is directed along the conduit 66A to the valve 60 in order to enter the internal gas chamber 81 and return to the surface, as described above.

[0064] The power piston 112 is mechanically coupled or linked to a production piston 135 that is a component of the production fluid assembly 502. The mechanical coupling can be achieved by a sleeve 520 that is fixed to the power piston 112 at one end and to the production piston 135 at the other end. The sleeve 520 can be cylindrical in order to accommodate the central conduit 508 around which the sleeve 520 is positioned. The sleeve 520 can slide along the outer surface of the central conduit 508 or there can be a gap therebetween. In operation, when the power piston 112 moves in a first direction, such as in the uphole direction due to the position of the valve 60, the production piston 135 will move the same distance in the same direction, which can also be referred to as the stroke length or stroke distance.

[0065] The production fluid assembly 506 includes an outer wall 530, which is similar to the power assembly 502 and the power actuator assembly 504, and can form part of the outer housing of the pumping assembly 500, or it can be a discrete structure that, together with the outer walls of the power assembly 502 and the power actuator assembly 504, defines the outer surface 500C of the pumping assembly 500.

[0066] The production fluid assembly 506 further includes a cylinder 532 within which a production piston 135 is slidably movable in two directions. The cylinder 532 has a first end 532A that defines a first end 500A and a second end 532B that is adjacent to the power actuator assembly 504 (see Figure 2 B). As will be understood by those skilled in the art, the production fluid assembly 504 is configured to include various seals to perform the functions described herein. Similar to the power piston 112, the production piston 135 can be a double-acting piston having a first face 135A and a second face 135B. The cylinder 532 and the piston 135 define two pumping chambers. A first fluid pumping chamber 130 is defined between the first face 135A and the first end 532A, and a second fluid pumping chamber 132 is defined between the second face 135B and the second end 532B. When the production fluid piston 125 moves, due to the operable link with the power piston 112, the volumes within the two chambers 130, 132 will change, with one volume increasing while the other volume decreasing, resulting in opposite pressure changes. For example, Figure 2 A depicts a situation where the valve 60 is directing the power fluid 55 into the power actuator assembly 504 such that the power piston 112 moves in the uphole direction. Due to the sleeve 520, the production fluid piston 135 also moves in the uphole direction, causing the volume of the first chamber 130 to decrease and the pressure therein to increase. In the second chamber 132, when the production fluid piston 135 moves in the uphole direction, the volume increases and the pressure decreases. When the valve 60 changes position to direct the power fluid 55 into the power actuator assembly 504, the opposite occurs, i.e., the volume of the first chamber 130 increases and the pressure therein decreases, while the volume in the second chamber 132 increases and the pressure therein decreases.

[0067] The outer wall 530 includes at least two sets of ports 23, 23A and two sets of valves 141, 142 that provide fluid communication between the exterior of the outer wall 530 of the pumping assembly 500 and the interior of the cylinder 532. For example, the port 23A (see Figure 2 A) can provide fluid communication between the exterior of the pumping assembly 500 and the first face 135A of the production piston 135. The port 23 (see Figure 2B) can provide fluid communication between the exterior of the pumping assembly 500 and the second face 135B of the production piston 135. When the pumping assembly 500 is positioned within the well, the pumping assembly 500 will be submerged in various fluids including production fluid, and ports 23, 23A can provide production fluid that will be received within either chamber 130, 132 of the cylinder 532. Whether these fluid communication flow paths are open or closed depends on the operable positions of the valve assembly consisting of valves 141, 142, 151 and 152 and the corresponding pressures within the chambers 130, 132 that each valve controls fluid entry into. Valve 141 controls fluid communication between the second chamber 132 and port 23A to regulate the flow of production fluid through port 23A. Valve 142 controls fluid communication between the second chamber 132 and the annular fluid chamber 529 defined between the outer wall 530 and the cylinder 532. Valve 142 is configured to regulate the flow of pressurized received production fluid into the annular fluid chamber 529, from which the fluid flows through the first end 500A, through the connector 170 and into the fluid delivery system 606. The annular fluid chamber 529 extends between the first and second ends of the production fluid assembly 506. Valve 151 controls fluid communication between the annular fluid chamber 529 and the connector 170. Valve 152 controls fluid communication between the first chamber 130 and the connector 170.

[0068] Figure 2 A shows two dashed lines A and B. Line A indicates a cross-sectional cut through the valve assembly at the first end 532A of the production fluid assembly 506. Line B indicates a cross-sectional cut through the valve assembly at the second end 532B of the assembly 506. Lines A and B together are used to represent the situation when the valve 60 directs the power fluid 55 to move the pistons 112 and 135 in the uphole direction. Figure 2 B shows two additional dashed lines C and D. Line C indicates a cross-sectional cut through the valve assembly at the first end 532A, and line D indicates a cross-sectional cut through the second end 532B. Lines B and C together are used to represent the situation when the valve directs the power fluid 55 to move the pistons 112 and 135 in the downhole direction.

[0069] Figure 3 A shows a cross-sectional view obtained from lines A and B. Below line A, the outer surface is shown as the outer wall 530, as described above herein, which represents the outer surface 500C of the pumping assembly 500. Between the outer wall 530 and the outer surface of the cylinder 532 (not shown in this view) is the annular fluid chamber 529. Facing the observer is the valve seat 155, which can define at least a portion of the first end 532A of the cylinder 532. In the center is the central pipe 508, within which is located the inner pipe 510. Although Figure 3A shows the operating positions of three sets of valves 151 and 152 and three sets of valves 141 and 152, but there can be more or fewer of these valves. Below line B, the outer wall 530 and the annular fluid chamber 529 are shown, and also includes a valve seat 140, which can define at least a part of the second end 532B of the cylinder 532. In Figure 3 In A, the valves 151 and 142 are shaded to indicate that they are in the closed operating position to prevent fluid communication therethrough. The valves 152 and 141 are shown unshaded to indicate that they are in the open operating position, allowing fluid to pass through. Figure 3 B shows the same structure as Figure 3 A, except that the valves 152 and 141 are closed and the valves 151 and 142 are open. The valves of the valve assembly can be one-way check valves, such as ball float valves, where the position (open or closed) of the valve is determined by the pressure difference across the valve. For example, Figure 3 the open / closed position of the valves in A is determined by the pressure in the fluid pumping chambers 130, 132 relative to the pressure on the opposite side of each valve.

[0070] For example, when the valve 60 causes the pistons 112, 135 to move in the uphole direction (as in Figure 2 A), the pressure in the second chamber 132 is lower than the ambient pressure of the production fluid surrounding the pumping assembly 500 and can continue to decrease. This causes the valve 141 to open, such that production fluid can be received in the chamber 132 via port 23A. At the same time, the pressure in the annular fluid chamber 529 exceeds the pressure in the chamber 132, and this causes the valve 142 to close. When the pistons 112, 135 move in the uphole direction, the pressure in the first chamber 130 increases and will exceed the pressure of the surrounding production fluid, which causes the valve 151 to close and reservoir fluid not to be received in the chamber 130. The pressure in the chamber 130 also causes the valve 152 to open to allow the production fluid received (and pressurized) therein to flow out of the production fluid assembly 506 and into the connector 170. In effect, Figure 2 A depicts the operating position of the valve assembly, whereby production fluid is drawn into the chamber 132, and the production fluid received in the chamber 130 is pumped out into the connector 170.

[0071] Figure 2 B depicts the operating position of the valve assembly, where the valves 141 and 152 are closed, and the valves 151 and 142 are open. This operating position directs the production fluid received in the chamber 132 to flow through the annular fluid chamber 529 and into the connector 170, and cuts off the fluid communication between the chamber 132 and the outside of the production fluid assembly 506. This operating position also allows new production fluid to be received into the chamber 130 via port 23.

[0072] Figure 4illustrates a pumping assembly 500 including a connector 170 positioned within a wellbore 15 and submerged in a production fluid (depicted by the hollow arrow). The operating position of the valve assembly of the production fluid assembly 506 is the same as that shown in Figure 2 A and Figure 3 shown in A such that production fluid can be received within chamber 132 of the production fluid assembly 506 via port 23A. The connector 170 includes a first end 170' operably coupled to the downhole end of a fluid delivery system 606 and a second end 170'' operably coupled to the first end 500A of the pumping system 500. The connector 170 is configured to provide fluid communication between the downhole end of the fluid delivery system 606 and a central bore for receiving and internalizing a channel of an electrical conductive system 608. Although in Figure 4 the connector 170 is shown as having an outer diameter larger than the outer surface 500C of the pumping assembly 500, this is merely to assist in depicting the features and functions of the connector 170. In fact, the outer diameter of the connector 170 is the same as or smaller than the outer diameter of the outer surface 500C. The connector 170 is configured to operably couple to the first end 500A of the pumping assembly 500. Specifically, the connector 170 provides one or more internal conduits for conveying pressurized received production fluid received from the production fluid assembly 506, as described above. The fluid delivery system 606 includes a production line 10 for conveying the pressurized received production fluid 25 from the connector 170 upward to the wellhead 20. The fluid delivery system 606 also includes a hydraulic delivery line 610 providing an extension of conduits 56 and 66 (see Figure 6 A). Specifically, the line 610 is configured to accommodate an extension 56A of the conduit 56 positioned within the conduit 66, optionally concentrically positioned within the conduit 66 such that motive fluid 55 flows internally and in a direction opposite to the discharge fluid 65 through the fluid delivery system 606. The line 610 is configured to fluidly and sealingly connect to a string adapter 171 of the connector 170 to receive and maintain the isolation and flow direction of the motive fluid 55 and the discharge fluid 65, pass them through the internal fluid channel system 173 of the connector 170, and convey them to fluid communication with the central conduit 508 (see Figure 6 B). Specifically, the motive fluid 55 within the conduit 56 of the line 610 is conveyed through the internal fluid channel system 173 of the string adapter 171, through the connector 170, and into the internal conduit 510. The discharge fluid 65 flows through the annulus of the central conduit 508, through the internal fluid channel system 173 within the connector 170 to enter the extension 65A for conveyance to the surface. Although Figure 6B shows an internal fluid channel system 173 with corners, but those skilled in the art will understand that it may be advantageous to make all corners rounded, smooth, or substantially straight to reduce, mitigate, or eliminate any negative impacts that such a change in direction may have on maintaining the pressure of the motive fluid 55.

[0073] The connector 170 also includes a production string adapter 172 for fluidly and sealingly connecting the production conduit 10 to the connector 170 to facilitate the conveyance of pressurized received production fluid 25 from the production fluid assembly 506. The connector also includes a central channel 56F and a secondary channel 66F. The central channel 56F can fluidly couple the power conduit 56 to the internal conduit 510 of the pumping assembly 500. The secondary channel 66F can fluidly couple the discharge conduit 66 to the discharge output stream of the downhole pumping assembly 500.

[0074] The connector 170 also includes an internal channel for conveying electrical conductors of the conductive system 608 therethrough. This internal channel for electrical conductors is configured to receive electrical conductors from the exterior of the fluid conveyance system 606 and internalize the electrical conductors such that they can extend from the connector 170 through the internal channel of the pumping assembly 500 to electrically transmit electrical signals from the controller 400 to the valve 60.

[0075] Figure 5 A variant 170Z of the connector is shown, and except that the conductive system 608 is conveyed downward through the wellbore 15 within the fluid conveyance system 606, all other features described above with respect to Figure 4 and Figure 6 A Figure 6 and Figure 5 B are the same as those in Figure 6 Specifically, the conductive system 606 can be positioned within the extension 66A such that the electrical conductors are within the low-pressure discharge fluid 65. However, as those skilled in the art will understand, suitably and adequately shielded electrical conductors can also be conveyed through the extension 56A of the fluid conveyance system 606. As is known and commonly understood in the art, the conductive system 608 allows electrical signals generated at the controller 400 to be transmitted downhole to change the operating position of the valve 60. The connector 170Z is configured to internalize the electrical conductors of the conductive system 608 as described above with respect to the connector 170. Figure 6 A depicts how the surface system 602 can be configured to receive and deliver the correct fluids into the correct conduits of the fluid conveyance system 606.

[0076] Figure 7Another variation of system 600 is shown, wherein fluid delivery system 606A includes three extended fluid conduits, where the first conduit (inner conduit) is nested within the second conduit (intermediate conduit), and the second conduit is nested within the third conduit (outer conduit). In some embodiments, the first, second, and third conduits may be arranged coaxially with each other, and optionally concentrically with each other. The three extended fluid conduits may be collectively referred to as a triple conduit. As Figure 8 shown in FIG. A, the inner conduit may be extension 55A, which is positioned within extension 65A, which is positioned within extension 10A of production line 10. Figure 8 FIG. A depicts how above-ground system 602 may be configured to receive and deliver the correct fluid into the correct conduit of fluid delivery system 606A.

[0077] Figure 8 FIG. B shows a closer view of another variation 170A of a connector for use with fluid delivery system 606A. Connector 170A may be configured to provide fluid communication therethrough for delivering motive fluid 55, pressurized received production fluid from production fluid assembly 506, and discharge fluid from central conduit 508 to inner conduit 510. Connector 170A is also configured to internalize or not internalize the electrical conductors of electrical system 608, as described above. Connector 170A includes a low-pressure latch 171B for fluidly coupling with extension 66A, a high-pressure latch 172B for fluidly coupling with extension 56A, and a production coupler 173B, such as a production mandrel, for fluidly coupling with extension 10A.

[0078] As will be understood by those skilled in the art, the electrical conductors of system 608 may be enclosed or not enclosed within one or more conduits of fluid delivery system 606A.

[0079] Figure 9 Another variation of system 600 is shown, wherein fluid delivery system 606B includes two sets of two nested fluid conduits. As Figure 10 shown in FIG. A, each set of two nested fluid conduits includes an inner conduit and an outer conduit. One set of nested conduits 606B' may include extension 10A as the outer conduit and extension 66A as the inner conduit. Another set of nested conduits 606B'' may include extension 56A as the inner conduit and a second extension 10A as the outer conduit. Figure 10 FIG. A depicts how above-ground system 602 may be configured to receive and deliver the correct fluid into the correct conduit of fluid delivery system 606B.

[0080] As will be understood by those skilled in the art, the electrical conductors of system 608 may be enclosed or not enclosed within one or more conduits of fluid delivery system 606B.

[0081] Figure 10 FIG. B shows a closer view of another variant 170B of the connector for use with the fluid delivery system 606B. The connector 170B can be configured to provide fluid communication therethrough for delivering motive fluid 55 and effluent fluid from the central conduit 508 to the inner conduit 510. The connector 170B is also configured to internalize the electrical conductors of the electrical system 608, as described above, or not. The connector 170B can include a scoop head 171C for fluidly and sealingly engaging the outer surfaces of each of two sets of nested fluid conduits, a low-pressure latch 172B configured to fluidly connect, anchor, and seal with the extension 66A, a high-pressure latch 173B configured to fluidly connect, anchor, and seal with the extension 56A, and a concentric tandem adapter 174B configured to connect the outer surface of the extension 10A to the scoop head 171C.

[0082] Figure 11 Another variant of the system 600 is shown, where the fluid delivery system 606C includes a set of nested fluid conduits. As Figure 12 shown in FIG. A, each set of two nested fluid conduits includes an inner conduit and an outer conduit. Within the set of nested conduits, the extension 66A can be the outer conduit, and the extension 56A can be the inner conduit. Figure 11 and Figure 12 both further show that the wellbore 15 can serve as a conduit for directing pressurized received production fluid 25 into the wellbore 20. Figure 12 FIG. A depicts how the surface system 602 can be configured to receive and deliver the correct fluids into the correct conduits of the fluid delivery system 606C.

[0083] Figure 12 FIG. B shows a closer view of another variant 170C of the connector for use with the fluid delivery system 606C, which is configured to provide fluid communication therethrough for delivering motive fluid 55 and effluent fluid from the central conduit 508 to the inner conduit 510. The connector 170B is also configured to internalize the electrical conductors of the electrical system 608, as described above, or not. The connector 170C also includes one or more seal assembly, each seal assembly configured to connect to the outer surface of the connector 170C and for establishing a fluid seal against the inner wall of the conduit 15. The seal assembly 175 can include one or more seal elements 175A and one or more anchoring elements 175B, as understood in the art, and a concentric tandem adapter for fluidly connecting the extensions 55A and 66A to the inner fluid passage of the connector 170C such that when pressurized received production fluid passes through the connector 170C, it will move in the uphole direction through the wellbore 15 to the wellhead 20.

[0084] As will be understood by those skilled in the art, the electrical conductors of system 608 may or may not be enclosed within one or more conduits of fluid delivery system 606C.

[0085] Figure 13 Another variation of system 600 is shown, where fluid delivery system 606D includes three separate fluid conduits. As Figure 14 shown in A, extension 55A may be one of the separate fluid conduits, extension 66A may be one of the separate fluid conduits, and extension 10A may be one of the separate fluid conduits, and extension 56A may be an inner conduit. Figure 11 and Figure 12 both further show that wellbore 15 may serve as a conduit for guiding pressurized received production fluid 25 into wellbore 20. Figure 14 FIG. A depicts how surface system 602 may be configured to receive and deliver the correct fluid into the correct conduit of fluid delivery system 606D.

[0086] Figure 14 FIG. B shows a closer view of another variation 170D of a connector for use with fluid delivery system 606D, which is configured to provide fluid communication therethrough for delivering power fluid 55 and effluent fluid 65 from central conduit 508 to inner conduit 510. Connector 170D is also configured to internalize the electrical conductors of conductive system 608, as described above, or not to internalize them. Connector 170D may include a high-pressure series adapter 171D for fluidly connecting extension 56A to a suitable inner fluid passage of connector 170D, a low-pressure series adapter 172D for fluidly connecting extension 66A to a suitable inner fluid passage of connector 170D, and a production series adapter for fluidly connecting extension 10A to a suitable inner fluid passage of connector 170D.

[0087] Figure 15 Another variation of system 600 is shown, where fluid delivery system 606D includes two inner conduits nested within an outer conduit. As Figure 16 shown in A, fluid delivery system 606D may include extension 10A as the outer conduit and extensions 56A, 66A as the inner conduits. In an embodiment, extensions 56A, 66A are sized to allow production fluid to reach the surface throughput within extension 10A at a desired flow rate and are located within extension 10A, distal to production fluid outlet 25, to allow a flow path for guiding pressurized received production fluid into wellbore 20 within extension 10A.

[0088] Figure 16A depicts how the surface system 602 can be configured to receive and deliver the correct fluid into the correct conduit of the fluid delivery system 606D. For example, the hydraulic power fluid 55 can flow in the downhole direction via the extension 56A, and the return discharge power fluid 65 can flow in the uphole direction via the extension 66A. In some embodiments of the present disclosure, the electrical conductors of the system 608 are not located within the fluid delivery system 606D.

[0089] Figure 16 B shows a closer view of another variant 170E of the connector for use with the fluid delivery system 606D. The connector 170E is configured to provide fluid communication therethrough for delivering the power fluid 55 and the discharge fluid 65 from the central conduit 508 to the inner conduit 510. The connector 170E is not configured to internalize the electrical conductors of the conductive system 608. The connector 170E may include a high-pressure series adapter 171E for fluidly connecting the extension 56A to a suitable internal fluid passage of the connector 170E, a low-pressure series adapter 172E for fluidly connecting the extension 66A to a suitable internal fluid passage of the connector 170E, and a production series adapter for fluidly connecting the extension 10A to a suitable internal fluid passage of the connector 170E.

[0090] Figure 17 Another variant of the system 600 is shown, where the fluid delivery system 606E includes two inner conduits nested within an outer conduit. As Figure 18 shown in A, the fluid delivery system 606D may include the extension 10A as the outer conduit and the extensions 56A, 66A as the inner conduits.

[0091] As Figure 18 shown in A, the extensions 56A, 66A are sized to allow for sufficient throughput of production fluid flow within the extension 10A. As Figure 17 shown, the extensions 56A, 66A are generally located within the extension 10A to allow a fluid path around the extensions 56A, 66A, thereby allowing multiple flow paths for directing pressurized received production fluid into the wellbore 20. Figure 18 A depicts how the surface system 602 can be configured to receive and deliver the correct fluid into the correct conduit of the fluid delivery system 606D. In an embodiment, the electrical conductors of the system 608 are enclosed by one or more conduits of the fluid delivery system 606D.

[0092] Figure 18B shows a closer view of another variant 170F of the connector for use with a fluid delivery system 606D that is configured to provide fluid communication therethrough for delivering motive fluid 55 and effluent fluid 65 from central conduit 508 to inner conduit 510. Connector 170F is also configured to internalize the electrical conductors of electrical system 608, as described above. Connector 170F may include a high-pressure tandem adapter 171E for fluidly connecting extension 56A to a suitable internal fluid passage of connector 170F, a low-pressure tandem adapter 172E for fluidly connecting extension 66A to a suitable internal fluid passage of connector 170F, and a production tandem adapter for fluidly connecting extension 10A to a suitable internal fluid passage of connector 170F.

[0093] Without being bound by any particular theory, since valve 60 is located at the wellbore end of pumping assembly 500 within wellbore 15, the fluid in hydraulic power conduits 56, 56A always flows downward to pumping assembly 500, and the effluent fluid in conduits 65, 65A always flows upward. The flow directions of these fluids do not reverse, such that the momentum effects on the thousands of feet of fluid included can be neglected. This avoids problems that can occur in systems where the hydraulic fluid flow direction is switched at the surface. When the flow stops or its direction is changed by a valve at the surface, only the length of the conduit that transports the hydraulic fluid column between the surface switching valve and the hydraulic actuator piston will be subjected to stress first caused by the stoppage of fluid flow, resulting in a drop in the internal conduit pressure above the associated actuator. This can cause fluctuations in the internal conduit pressure in another conduit above the associated actuator, as the pressure from above collides with the continued upward flow of the hydraulic fluid in this conduit that was previously just under the upward pump pressure. These stresses are similar to the 'water hammer' effect and cause excessive and unnecessary stress and strain on the conduits, connectors, seals, joints, and other fluid delivery equipment. In those hydraulic systems, the hydraulic power from the surface source will be mainly wasted on the thousands of feet long, rapidly flowing pressure oil column that reciprocates, and will leave little power in the oil column to power the actuator at the bottom end of the column. This system 600 of the present disclosure can solve this problem by placing valve 60 in a downhole position, and since power assembly 504 does not change the flow direction of motive fluid 55 or effluent fluid 65, the 'water hammer' effect can be reduced or substantially eliminated.

[0094] The stroke length of the piston will depend on the deviation of wellbore 15 from the desired length of the rigid pumping assembly 500 that can be accommodated. The pistons 112 and 135 disclosed herein can have a stroke length of any length, but the preferred range of the stroke length is about 10 feet (more or less), which is similar to that of a conventional or regular sucker rod pump device - this allows compatibility with conventional hardware and methods if needed.

[0095] For clarity, it should be noted that valve 60 can actually be implemented by a series of valves, where one valve cycles between closed (idle or bypass) and open (to allow flow to the next valve), and the next valve in the pipeline cycles between a direct and a cross hydraulic circuit. In this case, the bypass valve can be controlled from the surface, while the direct valve / conversion valve can be locally controlled (at the power unit 502). Various possible control circuits and valve arrangements are possible. In some embodiments, there can be a switching valve (a direction switching valve between the direct and cross circuits) and two limit switches (for maximum stroke, one switch is located at or near the end of the stroke, assembled such that there is a limit switch at a position where the piston of the system will be near the end of linear movement in one direction, and another limit switch at the end of the linear movement of the piston in the opposite direction of its stroke - these pistons do not have to be the same piston). These limit switches can be wired to the surface via an electrical signal conduit that is electrically connected to the controller 400, and this electrical signal conduit can direct the switching valve in the downhole direction to the direct position or the cross position (and to the bypass position if equipped). Depending on the configuration of the electrical control circuit and the controller functionality, the control signal can be provided from either one or both of the downhole limit switches or from the surface controller system, and this control signal can be automatic or accomplished through manual operation. Through feedback to the controller 400 and feedback from the surface flow sensing and control devices, various stroke lengths can be obtained, which can direct the switch to change the direction of the hydraulic flow circuit in the actuator or otherwise control the hydraulic fluid flow rate and the power from the surface. To integrate all those complex controller functions, the PLC 402 at the surface equipment will play a central role, where all system devices, including valve 60 and all temperature and pressure devices located anywhere in the entire system, will be centrally controlled and displayed by the PLC 402.

[0096] The position of valve 60 can be determined by a command received from the PLC 402 via the electrical conductor system 608. As will be understood by those skilled in the art, the electrical components of valve 60, such as solenoids, can be temperature-dependent, such that if valve 60 is exposed to large temperature fluctuations (e.g., when the applicable underground reservoir has undergone a heating event), the electrical components of valve 60 can fail. If the electrical components of valve 60 fail, the entire downhole pumping system 500 must be pulled to the surface for maintenance and / or repair, which results in operational delays, and the costs associated with maintenance and / or repair and production downtime can be very high.

[0097] Figure 19 and Figure 20Illustrations of the system 650 are shown. The system 650 includes a surface system 602 of the device and an underground system 604 of the device, which have many features identical to those described above for the system 600. However, the surface system 602 of the device of the system 650 further includes a switching valve 37 operably coupled to the power conduit 56 and the discharge conduit 66. The switching valve 37 can be actuated between a first position and a second position for regulating (or controlling) the flow of fluid through the conduits 56, 66. In the first position, the switching valve 37 fluidly regulates the flow of power hydraulic fluid from the surface system 602 to the downhole pumping assembly 500 by maintaining fluid communication between a first portion 56C of the conduit 56 positioned between the tank 85 and the check valve 37 and a second portion 56D of the conduit 56 positioned between the switching valve 37 and the downhole pumping assembly 500. In the first position, the switching valve 37 fluidly regulates the flow of discharge hydraulic fluid between the downhole pumping assembly 500 and the surface system 602 by maintaining fluid communication between a first portion 66C positioned between the tank 85 and the check valve 37 and a second portion 66D positioned between the check valve 37 and the downhole pumping assembly 500.

[0098] When the switching valve 37 is actuated to the second position, the switching valve 37 fluidly connects the first portion 56C of the power conduit 56 to the second portion 66D of the discharge conduit 66. Similarly, in the second position, the switching valve 37 fluidly connects the first portion 66C of the discharge conduit 66 to the second portion 56D of the power conduit 56. Optionally, the switching valve 37 can be moved to a third position, thereby stopping the fluid communication therethrough.

[0099] In some embodiments of the present disclosure, the position of the switching valve 37 is controlled by a controller 400. In particular, the PLC 402 can operably control a control mechanism 39, such as a solenoid or a limit switch. Such that if a command originates from the PLC 402, the command is received by the control mechanism 39, which in turn can change the position of the switching valve 39 between the first position and the second position, and vice versa.

[0100] The system 650 further includes a modification of the valve 60 of the power assembly 502. The valve 60 can include a check valve 38 located within the housing of the valve 60. During normal operation, the check valve 38 will remain closed due to the flow of hydraulic fluid through the valve 60. When the switching valve 37 reverses the flow direction of the fluid, the check valve 38 will automatically open, and the hydraulic fluid (power fluid and discharge fluid) will flow through the flow passage of the valve 60 substantially continuously or continuously. During normal downhole pumping operations for generating production fluid, the check valve 38 is closed, and no fluid flows through the check valve 38. Due to the switching valve 37 changing its position, the check valve 38 can only be opened by the reversed flow of power fluid.

[0101] During normal operation of the system 650, which means when the downhole pumping assembly 500 pumps production fluid in the uphole direction to the surface, the switching valve 37 is in the first position and the valve 60 is positioned as described above. However, if the operation of the system 650 stops for any reason, the flow of hydraulic fluid and production fluid through the downhole pumping system 500 will stop. This can cause operational problems and equipment failures because the electronic components and hydraulic components (pumps, motors, and seals) of the downhole pumping system 500 are designed to operate in a temperature environment up to approximately 100 °C. If the flow of hydraulic fluid through the system 650 stops, the downhole pumping system 500 will start to heat up, for example when the downhole pumping system is placed in a reservoir that has been subject to heat activity processes. To address this issue, the PLC 402 can send a command to the switching valve 37 to actuate to the second position. The flow of hydraulic fluid through the power conduit 56 and the discharge conduit 66 will reverse, in which case the check valve 38 will open. Since the check valve 37 is in the second position, i.e., the open position, the reverse flow of hydraulic fluid causes the hydraulic power fluid to enter the power assembly 502 via the discharge conduit 66. The high pressure of the hydraulic power fluid will cause the check valve 38 in the operating position to open, allowing the power hydraulic fluid to flow through the power assembly 502 and then return to the second section 56D and back to the tank 85 via the first section 66C of the discharge conduit 66. In this way, the system 650 has a countercurrent circulation loop that allows the power hydraulic fluid to flow substantially continuously or continuously into and out of the downhole pumping assembly 500 even when the operation of the downhole pumping assembly 500 stops. This flow of power hydraulic fluid can prevent the downhole pumping assembly 500 from overheating.

[0102] Without being bound by any particular theory, embodiments of the system 650 have been tested and proven that the electronic components and hydraulic components of the downhole pumping system 500 continue to operate at temperatures well above 100 °C. Some tests show that the system continues to operate at temperatures above approximately 200 °C and up to about 250 °C. Additionally, the system 650 demonstrates that it can maintain effective hydraulic control of the downhole pumping assembly 500 at depths between approximately 500 meters and approximately 2000 meters using the solenoid control valve 60 while avoiding the water hammer effect that can interfere with other known hydraulic control systems for downhole pumping systems.

[0103] While Figure 19 , Figure 20 and Figure 21 indicate the use of the switching valve 37 and the check valve 38 in the system 650, and Figure 21Specifically shown is a system 650 including a fluid delivery system 606, but it should be understood that this is not intended to be limiting. The switching valve 37 and the check valve 38 described herein can be deployed to provide a reversible hydraulic fluid circuit to various systems, including a surface system 602 composed of equipment including a hydraulic fluid power source and a subsurface system 604 composed of equipment including a downhole pump. Various fluid delivery systems described herein may or may not be utilized.

[0104] Some embodiments of the present disclosure relate to a method 700 for reversing the direction of fluid flow through a system. The method 700 can be used by the various systems described above, such as a system for operating a pumping system. The method 700 includes the steps of establishing 702 a flow of a first fluid in a first direction between a first fluid source and a power assembly, wherein the power assembly distributes the first fluid for operating the pumping system; establishing 704 a flow of a second fluid in a second direction opposite to the first direction between the power assembly and a second fluid source, wherein the pressure of the second fluid is lower than the pressure of the first fluid; and reversing 706 the flow in the first direction to the second direction.

[0105] The reversing step 706 can include actuating 708 a switching valve that is operatively coupled to a first pipe through which the first fluid flows and a second pipe through which the second fluid flows. Actuating 708 the switching valve establishes a flow of the first fluid through a first portion (e.g., the first portion 56C) of the first pipe and a second portion (e.g., the second portion 66D) of the second pipe. Actuating 708 the switching valve can also establish a flow of the second fluid through a second portion (e.g., the second portion 56D) of the first pipe and a first portion (e.g., the first portion 66C) of the second pipe.

[0106] The reversing step 706 can further include the step of opening 710 a check valve in the power assembly to establish a flow of the first fluid through the power assembly in the second direction.

[0107] As described herein, the first fluid is a power hydraulic fluid, and the second fluid is a discharge hydraulic fluid.

[0108] As those skilled in the art will appreciate, the present disclosure contemplates further modifications of the above-described embodiments and variations of the system 600. For example, the nested pipes may be concentrically arranged, or non-concentrically arranged; the electrical conductors may extend from the surface to the pumping assembly 500 inside the pipes of the fluid delivery system, or not. The contents and flow directions of any given pipe described herein may be exchanged with those of another, so long as the circuit of the motive fluid and the discharge fluid is maintained and the pressurized and held production fluid is directed to the wellhead for treatment. The outer surface of the pumping assembly 500 may be defined by a separate housing, or it may be defined by the outer walls of the power assembly 502, the power actuator assembly 506, and the production fluid assembly 506. In the case where the pumping assembly 500 does not include such a housing, the outer surface 500C has a substantially constant outer diameter that is substantially free of any protruding members extending outwardly and / or radially therefrom. Each of the assemblies 502, 504, and 506 is operably coupled together according to mechanisms known in the art, so long as these mechanisms do not interfere with the central pipe 508 extending from the first end 500A of the power assembly 502 to the upper end of the well.

Claims

1. A fluid delivery system for providing fluid communication between a surface system of a device and a downhole pumping assembly, the fluid delivery system comprising: A first end and a second end defining an outer surface therebetween, the first end being connectable to the surface system of the device; One or more internal fluid conduits for providing fluid communication between the first end and the second end; And A connector connected to the second end for operably coupling the one or more internal fluid conduits to the downhole pumping assembly, the connector including a central passage, a secondary passage, and a production fluid passage.

2. The fluid delivery system according to claim 1, wherein, The diameter of the connector is equal to or less than the outer diameter of the downhole pumping assembly.

3. The fluid delivery system according to claim 1, wherein The one or more internal fluid conduits include a first conduit for conveying power fluid, the first conduit being fluidly connected to the central passage of the connector.

4. The fluid delivery system according to claim 3, wherein, The one or more internal fluid conduits include a second conduit for conveying produced fluid, the second fluid being fluidly connected to an internal passage.

5. The fluid delivery system according to claim 4, wherein, The power fluid has a higher pressure and a lower temperature than the produced fluid.

6. The fluid delivery system according to claim 4 or 5, wherein The first conduit is positioned within the second conduit.

7. The fluid delivery system according to any one of claims 3, 4, 5, or 6, further comprising a third conduit for conveying production fluid from the downhole pumping assembly in an uphole direction, the third conduit being fluidly connected to the production fluid passage.

8. The fluid delivery system according to claim 7, wherein, The first conduit and the second conduit are positioned within the third conduit.

9. The fluid delivery system according to claim 8, wherein, The third conduit is a wellbore.

10. The fluid delivery system according to claim 9, wherein, The third conduit is positioned within a wellbore.

11. The fluid delivery system according to claim 1, wherein, The one or more internal fluid conduits include a first set of nested fluid conduits and a second set of nested fluid conduits, wherein each set of nested fluid conduits includes an internal conduit positioned within an outer conduit.

12. The fluid delivery system according to claim 11, wherein, The outer conduit of each set of nested conduits is for conveying production fluid from the downhole pumping assembly in an uphole direction.

13. The fluid delivery system according to claim 11 or 12, wherein The internal conduit of the first set of nested fluid conduits is for conveying power fluid, and the internal conduit of the second set of nested fluid conduits is for conveying produced fluid, wherein the power fluid has a higher pressure and a lower temperature than the produced fluid.

14. The fluid delivery system according to any one of claims 1 to 13, wherein, At least one of the one or more internal fluid conduits houses one or more electrical conductors capable of extending from the first end to the second end.

15. The fluid delivery system according to any one of claims 1 to 14, wherein, The connector further includes an internal passage for internalizing and guiding the one or more electrical conductors from the second end for operable connection to the downhole pumping assembly.

16. The fluid delivery system according to claim 14, wherein, The one or more conductors extend through the connector for operable connection to the downhole pumping assembly.

17. The fluid delivery system according to any one of claims 1 to 15, further comprising one or more production string adapters for fluidly, sealingly, and fluidly communicatively connecting the one or more internal fluid conduits to the production passage.

18. The fluid delivery system according to claim 4, further comprising a switching valve operably positioned between a first portion and a second portion of the first conduit and between a first portion and a second portion of the second conduit.

19. The fluid delivery system according to claim 17, wherein, The switching valve is capable of being actuated between a first position and a second position. When in the first position, the switching valve establishes fluid communication between a first part and a second part of the first pipeline and between a first part and a second part of the second pipeline.

20. The fluid delivery system according to claim 18, wherein, When the switching valve is in the second position, the switching valve establishes fluid communication between the first part of the first pipeline and the second part of the second pipeline and between the first part of the second pipeline and the second part of the first pipeline.

21. A downhole pumping assembly, the assembly comprising: a. A first end and a second end, an outer surface being defined between the first end and the second end, the outer surface having a substantially constant outer diameter; b. A power assembly, near the second end and configured to direct power fluid; c. A production fluid assembly, near the first end and configured to receive wellbore fluid and including a production piston configured to direct the received wellbore fluid towards the first end; d. A power actuation assembly, positioned adjacent to the power assembly and in fluid communication with the power assembly, the power actuation assembly being operably coupled to the production fluid assembly, the power actuation assembly being configured to receive the power fluid and move the production piston via the operable coupling to direct the received wellbore fluid towards the first end, wherein the power assembly includes a switchable valve for directing the power fluid to a first face or a second face of a power piston of the power actuation assembly, and includes a check valve capable of being actuated between a first position and a second position. When in the first position, the check valve is closed. When in the second position, the check valve can be opened by the power fluid to reverse the flow direction of the power fluid through the power assembly.

22. The downhole pumping assembly according to claim 21, wherein, If the power assembly stops operating, the check valve can open.

23. The downhole pumping assembly according to claim 21, further comprising a fluid delivery system for delivering the power fluid to the power assembly and for delivering discharge fluid from the power assembly.

24. The downhole pumping assembly according to claim 21, wherein, The fluid delivery system includes a first end and a second end, an outer surface being defined between the first end and the second end, the first end being connectable to a surface system of the equipment; One or more internal fluid pipelines for providing fluid communication between the first end and the second end; And A connector, connected to the second end, for operably coupling the one or more internal fluid pipelines to the downhole pumping assembly, the connector including a central channel, a secondary channel, and a production fluid channel.

25. The downhole pumping system according to claim 22, wherein, One or more internal fluid pipelines include a power fluid pipeline for delivering the power fluid to the power assembly and a discharge fluid pipeline for delivering discharge fluid from the power assembly.

26. The downhole pumping system according to claim 23, wherein, The fluid delivery system further includes a switching valve for establishing fluid communication between a first part of the power fluid pipeline and a second part of the discharge fluid pipeline and for establishing fluid communication between a second part of the power fluid pipeline and a first part of the discharge fluid pipeline.

27. A method for reversing the flow of fluid within a system, the method comprising the steps of: a. establishing a flow of a first fluid in a first direction from a first fluid source to a power assembly, wherein the power assembly distributes the first fluid for operating a pumping system; b. establishing a flow of a second fluid between the power assembly and a second fluid source in a second direction opposite to the first direction, wherein the pressure of the second fluid is lower than the pressure of the first fluid; c. reversing the flow in the first direction to the second direction.

28. The method according to claim 25, wherein The reversing step includes actuating a switching valve that is operatively coupled to a first conduit through which the first fluid flows and a second conduit through which the second fluid flows.

29. The method according to claim 26, wherein Actuating the switching valve establishes a flow of the first fluid through a first portion of the first conduit and a second portion of the second conduit.

30. The method according to claims 26 and 27, wherein, Actuating the switching valve establishes a flow of the second fluid through a second portion of the first conduit and a first portion of the second conduit.

31. The method according to any one of claims 25 to 28, wherein, The reversing step further includes the step of opening a check valve in the power assembly to establish a flow of the first fluid in the second direction.

32. The method according to any one of claims 25 to 28, wherein The first fluid is a power hydraulic fluid.

33. The method according to any one of claims 25 to 27, wherein The second fluid is a discharge hydraulic fluid.

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