PUMPING SYSTEM FOR A WELLBORE AND METHODS OF ASSEMBLING THE SAME

Abstract

A pumping system for use in moving a fluid present within a wellbore is provided. The pumping system includes an electric linear motor having a motor housing and a stator coupled to the motor housing. The stator includes a track having a primary magnet assembly. A motor shaft is electrically coupled to the stator and includes a body having a secondary magnet assembly. The pumping system includes a pump coupled to the electric linear motor, which includes a pump housing coupled to the motor housing and a pump piston coupled to the motor shaft. The pump piston is configured to reciprocate within the pump housing between a second position and a first position. A seal is coupled to the motor housing and the motor housing and configured to direct the fluid into the pump housing when the pump piston is in the first position and to direct the fluid out of the pump housing when the pump piston is in the second position.

Description

BACKGROUND

The embodiments described herein relate generally to pumping systems, and more particularly, to methods and systems for selectively pumping a fluid out of a well casing of a wellbore.

In producing petroleum and other useful fluids from production wells, some well assemblies include submergible pumping systems for raising the fluids collected in the well. Production fluids enter the well casing via perforations formed in the well casing adjacent a geological formation. Fluids contained in the geological formation collect in the well casing and may be raised by the submergible pumping system to a collection point above the surface of the earth.

At least some known conventional pumping systems include a submergible pump, a submergible electric motor and a motor protector. The submergible electric motor typically supplies power to the submergible pump by a drive shaft, and the motor protector serves to isolate the motor from the well fluids. A deployment system, such as deployment tubing in the form of tubing strings, can be used to deploy the submergible pumping system within a wellbore. Generally, power is supplied to the submergible electric motor or motors by one or more power cables supported along the deployment system.

Conventional production wells may provide a high rate of fluid production in the early phase of the well life and may provide a lower rate of fluid production for the remainder of the well life due to lower levels of available fluid. Producing the well at an efficient recovery rate may require the installation of an initial pumping system having a high flow rate in the early phase of well life and then replacing the initial pumping system with another pumping system having a lower flow rate one or more times over the life of the well. However, typical replacement pumping systems can wear out quickly, and in particular, the pump piston is especially vulnerable due to the harsh conditions of the geological formation. Replacing pumping systems over the life of the well may increase design, operational, and/or maintenance costs of the well assembly. Moreover, at least some known conventional pump motors may include seals and encapsulation materials between the motor shaft and motor stator which may lead to interference and reduced electromagnetic performance of the pumping system.

BRIEF DESCRIPTION

In one aspect, a pumping system for use in moving a fluid present within a wellbore is provided. The pumping system includes an electric linear motor having a motor housing and a stator coupled to the motor housing. The stator includes a track having a primary magnet assembly. A motor shaft is electrically coupled to the stator and includes a body having a secondary magnet assembly. The body includes a first diameter. The pumping system includes a pump coupled to the electric linear motor. The pump includes a pump housing coupled to the motor housing and a pump piston coupled to the motor shaft and has a second diameter which is different than the first diameter. The pump piston is configured to reciprocate within the pump housing between a second position and a first position. A seal is coupled to the motor housing and the motor housing. The seal is configured to direct the fluid into the pump housing when the pump piston is in the first position and to direct the fluid out of the pump housing when the pump piston is in the second position.

A well assembly for pumping a fluid is provided. The well assembly includes a well casing having a first zone, a second zone and a plurality of perforations coupled in flow communication to the second zone. The well assembly further includes an electric linear motor having a motor housing and a stator coupled to the motor housing. The stator includes a track having a primary magnet assembly. A motor shaft is electrically coupled to the stator and includes a body having a secondary magnet assembly and a first diameter. The pumping system includes a pump coupled to the electric linear motor. The pump includes a pump housing coupled to the motor housing and a pump piston coupled to the motor shaft and having a second diameter which is less than the first diameter. The pump piston is configured to reciprocate within the pump housing between a second position and a first position. A seal is coupled to the motor housing and the pump housing. The seal is configured to direct the fluid into the pump housing when the pump piston is in the first position and to direct the fluid out of the pump housing when the pump piston is in the second position.

A method of assembling a pumping system is provided. The method includes coupling a stator to a motor housing, wherein the stator includes a primary magnet assembly. A motor shaft is coupled to the stator and includes a secondary magnet assembly. The motor shaft includes a first diameter. The method also includes coupling a pump housing to the motor housing. A pump piston is coupled to the motor shaft. The pump piston has a second diameter which less than the first diameter and is configured to reciprocate within said pump housing between a second position and first position. The method further includes coupling a seal to the motor housing and the piston housing, wherein the seal configured to direct the fluid into the pump housing when the pump piston is in the first position and to direct the fluid out of the pump housing when the pump piston is in the second position.

DRAWINGS

These and other features, aspects, and advantages will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:

FIG. 1 is a cross-sectional side view of a well assembly having an exemplary pumping system vertically coupled to the wellbore;

FIG. 2 is cut-away, perspective view of an electric linear motor and a pump of the pumping system shown in FIG. 1;

FIG. 3 is another cross-sectional side view of the electric linear motor and the pump shown in FIG. 1 and a seal coupled to the electric linear motor and the pump;

FIG. 4 is a cross-sectional side view of the electric linear motor, the pump and the seal in a first position;

FIG. 5 is a cross-sectional side view of the electric linear motor, the pump and the seal in a second position;

FIG. 6 is a cross-sectional side view of an alternative pumping system in a first position;

FIG. 7 is a cross-sectional side view of the pumping system shown in FIG. 6 in a second position;

FIG. 8 is a cross-sectional side view of an alternative pumping system in a first position;

FIG. 9 is a cross-sectional side view of the pumping system shown in FIG. 8 in a second position;

FIG. 10 is a cross-sectional side view of yet another alternative pumping system in a first position;

FIG. 11 is a cross-sectional side view of the pumping system shown in FIG. 10 in a second position;

FIG. 12 is a flowchart illustrating an exemplary method of assembling a pumping system shown in FIG. 1;

FIG. 13 is a cross-sectional view of a pump piston and a valve for use with the pumping system shown in FIG. 1;

FIG. 14 is a cross-sectional view of a pump piston and a valve for use with the pumping system shown in FIG. 1;

FIG. 15 is a cross-sectional view of a pump piston and a valve for use with the pumping system shown in FIG. 1;

FIG. 16 is a cross-sectional view of an alternative pumping system in a first position;

FIG. 17 is a cross-sectional side view of the pumping system shown in FIG. 16 in a second position; and

FIG. 18 is a cross-sectional view of an alternative pumping system.

Unless otherwise indicated, the drawings provided herein are meant to illustrate features of embodiments of the disclosure. These features are believed to be applicable in a wide variety of systems comprising one or more embodiments of the disclosure. As such, the drawings are not meant to include all conventional features known by those of ordinary skill in the art to be required for the practice of the embodiments disclosed herein.

DETAILED DESCRIPTION

In the following specification and the claims, reference will be made to a number of terms, which shall be defined to have the following meanings The singular forms “a”, “an”, and “the” include plural references unless the context clearly dictates otherwise. “Optional” or “optionally” means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where the event occurs and instances where it does not.

Approximating language, as used herein throughout the specification and claims, may be applied to modify any quantitative representation that could permissibly vary without resulting in a change in the basic function to which it is related. Accordingly, a valve modified by a term or terms, such as “about” and “substantially”, are not to be limited to the precise valve specified. In at least some instances, the approximating language may correspond to the precision of an instrument for measuring the valve. Here and throughout the specification and claims, range limitations may be combined and/or interchanged, such ranges are identified and include all the sub-ranges contained therein unless context or language indicates otherwise.

The embodiments described herein relate to pumping systems and methods of pumping a fluid from a well assembly. The embodiments also relate to methods, systems and/or apparatus for controlling pumping of production fluid to facilitate improvement of well production performance. More particularly, the embodiments described herein reduce electromagnetic interference and enhance electromagnetic performance of a linear motor and pump assembly by providing different magnetic assemblies for the linear motor. It should be understood that the embodiments described herein include a variety of types of well assemblies, and further understood that the descriptions and figures that utilize a linear motor are exemplary only. The exemplary pumping system positively displaces a production fluid at different production rates to efficiently operate the well assembly over extended periods of time.

FIG. 1 is a cross-sectional side view of a well assembly 10 having a pumping system 12 vertically coupled to a wellbore 14 via a wellhead 16. Pumping system 12 includes an electric linear motor 18 and a pump 20. Pumping system 12 is designed for deployment in wellbore 14 within a geological formation 22 containing desirable production fluids 24, such as, but not limited to, petroleum. Wellbore 14 is drilled into geological formation 22 and lined with a well casing 26. Well casing 26 includes an inner sidewall 28, an outer sidewall 30, a casing bore 32 defined by inner sidewall 28, and a casing end 29. Well casing 26 defines a first zone 34 and a second zone 36 therein. In the exemplary embodiment, first zone 34 is vertically located above second zone 36. Alternatively, well casing 26 may be positioned in any orientation within geological formation 22 and may include any number of zones in any orientation to enable pumping system 12 to function as described herein. A plurality of perforations 38 is formed through well casing 26 to permit fluid 24 to flow into wellbore 14 from geological formation 22 and into second zone 36. Alternatively, perforations 38 can be formed through well casing 26 to permit fluid 24 to flow into wellbore 14 from geological formation 22 and into first zone 34. Pumping system 12 includes a seal assembly 40 coupled to electric linear motor 18 and pump 20.

A motor controller 42 is coupled to linear motor 18 by power cables 50. Motor controller 42 includes a rectifier 44, an inverter 46, a programmable logic controller (PLC) 48, one or more electrical sensors (not shown), and one or more electrical indicators (not sown) such as, but not limited to, a voltmeter and one or more ammeters. Alternatively, any programmable control device configured to process executable instructions to enable pumping system 12 to operate as described herein may be used. Motor controller 42 is configured to receive a three phase alternating current (AC) power signal from a utility grid or generator (neither shown). Rectifier 44 is configured to convert the three phase AC power signal to a direct current (DC) power signal and supply the converted DC power signal to inverter 46. Inverter 46 includes an output for each stator phase of motor 18 and may modulate the DC power signal to drive each phase of motor 18 based on control signals from PLC 48. Sensors (not shown) may measure voltage and current of one or more of the inverter outputs and be in data communication with PLC 48. Well assembly 10 further includes a production string 52 coupled to wellhead 16 and to pumping system 12. In the exemplary embodiment, pumping system 12 is configured to pump fluid 24 from geological formation 22 to wellhead 16.

FIG. 2 is a cross-sectional view of electric linear motor 18 and pump 20. FIG. 3 is another cross-sectional view of linear motor 18, pump 20 and seal assembly 40 coupled to linear motor 18 and pump 20. FIG. 4 is a cross-sectional view of linear motor 18, pump 20, and seal assembly 40 in a first position 54 such as, but not limited to, a return position. FIG. 5 is a cross-sectional view of linear motor 18, pump 20, and seal assembly 40 in a second position 56 such as, but not limited to, a discharge position. In the exemplary embodiment, linear motor 18 includes a motor housing 58 having a first motor end 60, a second motor end 62, and a motor body 64 located between first motor end 60 and second motor end 62. Motor body 64 includes an outer surface 66 coupled to well casing 26 (shown in FIG. 1) and an inner surface 68 defining a motor bore 70. Motor body 64 includes a first length L1 between first motor end 60 and second motor end 62. In the exemplary embodiment, first length L1 has a range between about 70 inches and about 90 inches. More particularly, first length L1 is about 81 inches. Alternatively, motor body 64 has any length to enable linear motor 18 to function as described herein. A stator 72 is coupled to inner surface 68 and includes a track 74 having a primary magnet assembly 76. In the exemplary embodiment, primary magnet assembly 76 includes a plurality of magnetic windings 78 coupled to track 74. Magnetic windings 78 are configured in a 3-phase sequence 80.

Linear motor 18 includes a motor shaft 82 magnetically coupled to stator 72. Motor shaft 82 includes a body 84 having a secondary magnet assembly 86. In the exemplary embodiment, secondary magnet assembly 86 includes at least one permanent magnet 88. Alternatively, secondary magnet assembly 86 may include at least one of a plurality of magnetic windings, an induction cage, a magnetically permanent material having a magnetic flux pathway such as, but not limited to, a synchronous reluctance configuration and a switched reluctance configuration. Primary magnet assembly 76 and secondary magnet assembly 86 facilitate providing stationery support to magnetic windings 78 to reduce load stresses applied to magnetic windings 78 during operation of linear motor 18. Stationery support provided by motor shaft 82 facilitates enhancement of motor life by reducing mechanical breakdown caused by load stresses applied to the plurality of windings 78. More particularly, the mechanical stresses applied to moving motor shaft 82 are compensated or carried by the robust structure of solid metal components of control windings 78. Moreover, motor shaft 82 includes a first diameter D1 having a range between about 0.5 inches and about 3.5 inches. More particularly, first diameter D1 has a length of about 2.25 inches. In the exemplary embodiment, first diameter D1 includes a circular cross-sectional area. Alternatively, first diameter D1 can have any length to enable meter motor shaft 82 to function as described herein. Moreover, in an alternative embodiment, first diameter D1 can include other non-circular cross-sectional areas such as, but not limited to, an elliptical cross-sectional area.

Pump 20 includes a pump housing 90 coupled to motor housing 58 and located outboard of motor second motor end 62. Pump housing 90 has a first pump end 92, a second pump end 94, and a pump body 96 located between first pump end 92 and second pump end 94. First pump end 92 is coupled in flow communication to second motor end 62 and in flow communication with perforations 38 and second pump end 94 is located in second zone 36 (both shown in FIG. 1). Moreover, second pump end 94 is coupled in flow communication to casing end 29. Pump body 96 includes an outer surface 98 that is orientated toward well casing 26 (shown in FIG. 1) and an inner surface 100 defining a pump bore 102. Body 96 includes a second length L2 between first pump end 92 and second pump end 94. Second length L2 is different than first length L1. In the exemplary embodiment, second length L2 is less than first length L1. Second length L2 has a range between about 15 inches and about 25 inches. More particularly, second length L2 is about 16 inches. Second length L2 can include any dimension to enable pump 20 to function as described herein. Pump housing 90 further includes a coupler 104 such as, but not limited to, a flange that is configured to couple first pump end 92 in flow communication to second motor end 62. In the exemplary embodiment, flange 104 is removably coupled to at least one of second motor end 62 and first pump end 92 to facilitate removal and/or retrieval of pump housing 90 out of well casing 26 (shown in FIG. 1) without removing linear motor 18 from well casing 26. Alternatively, coupler 104 may be an integrated coupler such as, but not limited to, a weld. Coupler 104 may include any configuration to enable coupling between motor housing 58 and pump housing 90.

Pump 20 further includes a pump piston 106 coupled to motor shaft 82. Pump piston 106 includes a second diameter D2 that is different than first diameter D 1. In the exemplary embodiment, second diameter D2 is less than first diameter D1. In the exemplary embodiment, second diameter D2 includes a circular cross-sectional area. Second diameter D2 has a range between about 0.025 inches and about 2.5 inches. More particularly, second diameter D2 has a length of about 1.125 inches. First diameter D1 and second diameter D2 can include any dimension to enable pump 20 to function as described herein. Moreover, in an alternative embodiment, first diameter D1 can include other non-circular cross-sectional areas such as, but not limited to, an elliptical cross-sectional area. The arrangement of pump housing 90 outboard of motor housing 58 facilitates second diameter D2 being less than first diameter D1. Accordingly, motor shaft 82 has a greater cross-sectional area as compared to pump piston 106 which exposes more surface area of permanent magnet 88 to magnetic windings 78 which facilitates reducing first length L1 of linear motor 18. A reduced first length L1 increases efficiency and decreases operational maintenance and repair costs. In the exemplary embodiment, pump piston 106 is configured to reciprocate within motor housing 58 and pump housing 90 between first position 54 and second position 56.

Seal assembly 40 is coupled to motor housing 58 and pump housing 90. More particularly, seal assembly 40 includes a first valve 108 coupled in flow communication to second motor end 62 and first pump end 92. Seal assembly 40 further includes a second valve 110 coupled in flow communication to second pump end 94 and casing end 29. First valve 108 includes a first seat 101, a second seat 103, and valve device 105. Valve device 105 includes a one-way flow valve such as, but not limited to, a ball check valve, a swing check valve, and a diaphragm check valve. First seat 101 and second seat 103 are coupled to pump piston 106. In the exemplary embodiment, first seat 101, second seat 103, and pump piston 106 define a channel 107 therein. Channel 107 includes a first end 99 in flow communication with perforations 38. Channel 107 is configured to direct fluid 24 from perforations 38, through channel 107, beyond first seat 101 and second seat 103, and into pump bore 102. Second valve 110 includes a first seat 109, a second seat 111, and a valve device 113. Valve device 113 includes a one-way flow valve such as, but not limited to, a ball check valve, a swing check valve, and a diaphragm check valve. In an alternative embodiment, valve device 105 may be positioned within pump bore 102 and between end 99 and flange 104. Moreover, in an alternative embodiment, valve device 113 may be positioned within pump bore 102.

First valve 108 is in flow communication with motor bore 70 and pump bore 102 and can include any configuration to facilitate fluid 24 to flow from perforations 38 and into pump bore 102 and prevent flow of fluid 24 from pump bore 102 into motor bore 70. Second valve 110 is coupled in flow communication to pump bore 102 and casing bore 32 and can include any configuration to facilitate flow of fluid 24 within casing bore 32 and prevent flow of fluid 24 from casing bore 32 and into pump bore 102.

In first position 54 (FIG. 4), motor shaft 82 is configured to move pump piston 106 into motor bore 70. Pump piston 106 is configured to draw fluid 24, under a first piston pressure P1, from geological formation 22, through perforations 38, and into channel 107. First piston pressure P1 in channel 107 induces valve device 105 to move to an open position 114, represented by hash lines within valve 108. More particularly, in open position 114, valve device 105 is decoupled from first seat 101 and second seat 103 to facilitate flow of fluid 24 from perforations 38, through channel 107, and into piston bore 102. A seal 121 is configured to seal motor bore 70 from exposure to fluid 24. In the exemplary embodiment, motor shaft 82 can be coupled closely to stator 72 with minimal and/or no seals (not shown) and/or encapsulation materials (not shown) located between motor shaft 82 and magnetic windings 78. More particularly, minimal space between stator 72 and motor shaft 82 reduces and/or eliminates interference between magnetic windings 78 and permanent magnet 88 to facilitate enhancement of electromagnetic performance between magnetic windings 78 and permanent magnet 88. Moreover, in first position 54, first piston pressure P1 in pump bore 102 is less than a casing pressure CP of fluid 24 located in casing bore 32. Based at least on the pressure differential between first piston pressure P1 and casing pressure CP, casing pressure CP induces second valve 110 to move to closed position 115. More particularly, in closed position 115, valve device 113 is coupled to first seat 109 and second seat 111 and configured to seal pump bore 102 from casing bore 32. Moreover, in closed position 115, valve device 113 prevents fluid 24 in casing bore 32 from entering pump bore 102 and prevents fluid 24 in pump bore 102 from entering casing bore 32.

In second position 56 (FIG. 5), motor shaft 82 is configured to move pump piston 106 into pump bore 102. Pump piston 106 is configured to move first seat 101, second seat 103, and channel 107 to closed position 115. More particularly, in closed position 115, valve device 105 is coupled to first seat 101 and second seat 103 and configured to seal pump bore 70 from piston bore 102. Moreover, in closed position 115, valve device 105 seals channel 107 from piston bore 102 to prevent flow of fluid 24 from perforations, 38, through channel 107, and into piston bore 102. Moreover, pump piston 106 is configured to apply a second piston pressure P2 to fluid 24 within pump bore 102 as pump piston 106 moves first valve 108 from first pump end 92 and toward second pump end 94 and to closed position 115.

Second piston pressure P2 is greater than a formation pressure FP of fluid 24 located in geological formation 22. Based at least on pressure differences between second piston pressure P2 and formation pressure FP, second piston pressure P2 prevents fluid 24 flowing from geological formation 22, through perforations 38, and into pump bore 102. Moreover, second piston pressure P2 is greater than casing pressure CP of fluid 24 present in casing bore 32. Based at least on pressure differences between second piston pressure P2 and casing pressure CP, second piston pressure P2 induces second valve 110 to move to open position 114. More particularly, in open position 114, valve device 113 is decoupled from first seat 109 and second seat 111 to facilitate movement of fluid 24 from pump bore 102, through second pump end 94, and into casing bore 32 for future processing. Subsequent the discharge of fluid 24 from pump bore 102 and into casing bore 32, motor shaft 82 is configured to move pump piston 106 out of pump bore 102 and into motor bore 70.

During an exemplary operation of pumping system 12, motor controller 42 (shown in FIG. 1) sends a current signal 116 to stator 72. Current signal 116 flows along track 74 and through magnetic windings 78. A resultant magnetic field (not shown) interacts with magnetic windings 78 and permanent magnet 88 of motor shaft 82 to move motor shaft 82 within motor bore 70, and in particular, from second motor end 62 toward first motor end 60.

Motor shaft 82 moves pump piston 106 from pump bore 102, and into motor bore 70 to first position 54. Pump piston 106 creates negative first piston pressure P1 which induces movement in fluid 24 from geological formation 22 through perforations 38, through channel 107, and into pump bore 102. Moreover, first piston pressure P1 induces first valve device 105 to move and to decouple from first seat 101 and sealed seat 103 at open position 114. Seal 121 prevents fluid 24 from pump bore 102 from entering motor bore 70. First piston pressure P1 also moves second valve 110 to move and couple to second pump end 94 to closed position 115 to prevent fluid 24 from flowing from casing bore 32 into pump bore 102. More particularly, first piston pressure P1 induces valve device 113 to couple to first seat 109 and second seat 111. Alternatively, casing pressure CP can induce valve device 113 to couple to first seat 109 and second set 111 in second position 115.

In first position 54, movement of the motor shaft 82 and pump piston 106 allows ingress of fluid 24 from geological formation 22, through perforations 38, through channel 107, and into pump bore 102. Moreover, in first position 54, movement of motor shaft 82 and pump piston 106 moves valve device 111 to couple to second pump end 94 to seal pump bore 102 from fluids 24 present in casing 32.

Motor controller 42 (shown in FIG. 1) sends current signal 118 to stator 72. Current signal 118 flows within magnetic windings 78 to move motor shaft 82 to second position 56. Motor shaft 82 moves pump piston 106 from motor bore 70 and into pump bore 102. Pump piston 106 moves first valve 108 to couple first valve 108 to pump piston 106 and moves first valve 108 towards second pump end 94. More particularly, pump piston 106 moves first seat 101 and second seat 103 to couple to valve device 105. While moving first valve 108 from first pump end 92 to second pump end 94, pump piston 106 creates second piston pressure P2 within fluid 24 present in pump bore 102. Second piston pressure P2 is greater than formation pressure FP and prevents fluid 24 flowing from geological formation 22, through perforations 38, through channel 102, and into pump bore 102. Moreover, second piston pressure P2 is greater than casing pressure CP and induces second valve 110 to move to open position 114. More particularly, second piston pressure P2 induces valve device 113 to be coupled from valve seat 109 and valve seat 111 to move to open position 114. Second piston pressure P2 induces second valve 110 to move from second pump end 94 and discharge fluid 24 from pump bore 102 and into casing bore 32 for further processing by wellhead 16. At second position 56, motor controller 42 can send another current signal (not shown) to stator 72 to move motor shaft 82 back to first position 54 to reciprocally repeat the pumping process.

FIG. 6 is a cross-sectional side view of an alternative pumping system 120 in first position 54. FIG. 7 is a cross-sectional side view of pumping system 120 in second position 56. In FIGS. 6 and 7, similar components shown in FIGS. 1-5 include the same element number shown in FIGS. 1-5. Stator 72 includes a primary magnet assembly 122. In the exemplary embodiment, primary magnet assembly 122 includes permanent magnet 88 coupled to inner surface 68. Alternatively, primary magnet assembly 122 may include at least one of a plurality of magnetic windings, an induction cage, a magnetically permanent material having a magnetic flux pathway such as, but not limited to, a synchronous reluctance configuration and a switched reluctance configuration. Moreover, motor shaft 82 includes a secondary magnet assembly 124. In the exemplary embodiment, secondary magnet assembly 124 includes magnetic windings 78. Primary magnet assembly 122 and secondary magnet assembly 124 are configured to facilitate convenient and efficient removal of magnetic windings 78 without removal of stationary permanent magnet 88. More particularly, motor shaft 82 can be efficiently removed from motor bore 70 to facilitate convenient replacement of magnetic windings 78 for maintenance and/or replacement operations. Moreover, permanent magnet 88 of stator 72 remains coupled to inner surface 68, which reduces and/or eliminates interference with respect to motor shaft 82 removal and/or replacement.

During an exemplary operation, motor controller 42 (shown in FIG. 1) sends a current signal 125 to motor shaft 82. Current signal 125 flows through magnetic windings 78. A resultant magnetic field (not shown) interacts with permanent magnet 88 and magnetic windings 78 to move motor shaft 82 within motor bore 70 from second motor end 62 to first motor end 60 and to first position 54. In first position 54, pump piston 106 is configured to draw fluid 24 from geological formation 22, through perforations 38, through channel 107, and into pump bore 102 as previously described. Moreover, pump piston 106 is configured to move first valve 108 to open position 114. Additionally, second valve 110 is moved to closed position 115 and is configured to prevent flow of fluid 24 from casing bore 32 and into pump bore 102 as previously described.

Motor controller 42 (shown in FIG. 1) sends another current signal 127 to motor shaft 82. Current signal 127 flows through magnetic windings 78. A resultant magnetic field (not shown) interacts with permanent magnet 88 and magnetic windings 78 to move motor shaft 82 within motor bore 70 from first motor end 60 towards second motor end 62 and second position 56. In second position 56, pump piston 106 is configured to push first valve 108 from first pump end 92 to second pump end 94 and to closed position 115. Pump piston 106 moves fluid 24 within pump bore 102 toward casing bore 32. Moreover, pump piston 106 is configured to move fluid 24 through second pump end 94 to move second valve 110 to open position 114. In open position 114, pump piston 106 moves fluid 24 from pump bore 102, through second pump end 94, and into casing bore 32 for future processing.

FIG. 8 is a cross-sectional side view of an alternative pumping system 126 in a first position 128. FIG. 9 is a cross sectional view of pumping system 126 in a second position 130. In FIGS. 8 and 9 similar components shown in FIGS. 1-7 include the same element numbers as shown in FIGS. 1-7. In the exemplary embodiment, stator 72 includes primary magnet assembly 76 having magnetic windings 78 coupled to track 74. Moreover, motor shaft 82 includes secondary magnet assembly 86 having permanent magnet 88. Alternatively, secondary magnet assembly 86 may include at least one of a plurality of magnetic windings, an induction cage, a magnetically permanent material having a magnetic flux pathway such as, but not limited to, a synchronous reluctance configuration and a switched reluctance configuration. Pumping system 12 also includes another pump 132 coupled to linear motor 18. Pump 132 includes a pump housing 134 and a pump piston 136. Pump housing 134 includes a first pump end 138, a second pump end 140, and a pump body 142. Pump body 142 includes an outer surface 144 facing well casing 26 (shown in FIG. 1) and an inner surface 146 defining a pump bore 148. First pump end 138 is coupled to first motor end 60. Second pump end 140 is coupled to a well casing end 149. In the exemplary embodiment, coupler 104 couples pump housing 134 to motor housing 58. Moreover, perforations 38 are coupled in flow communication to geological formation 22 and pump bore 148. Seal assembly 40 includes a first valve 150 and a second valve 152.

During an exemplary operation of pumping system 12, motor controller 42 (shown in FIG. 1) sends current signal 116 to stator 72. Current signal 116 flows along track 74 and through magnetic windings 78. A resultant magnetic field (not shown) interacts with permanent magnet 88 and magnetic windings 78 to move motor shaft 82 within motor bore 70 from second motor end 62 to first motor end 60 and first position 128. In first position 128, pump piston 106 is configured to draw fluid 24 from geological formation 22, through perforations 38, through channel 107, and into pump bore 102 as previously described. Pump piston 106 is configured to move first valve 108 to open position 114. Additionally, in first position 128, second valve 110 is moved to closed position 115 to prevent flow of fluid 24 from casing bore 32 and into pump bore 102 as previously described.

Moreover, in first position 128, motor shaft 82 moves pump piston 136 into pump bore 148. Pump piston 136 is configured to couple first valve 150 to pump piston 106 and move first valve 150 from first pump end 138 to second pump end 140 to closed position 115. Pump piston 136 further moves fluid 24 within pump bore 148 toward casing bore 32. Pump piston 136 is configured to move fluid 24 through second pump end 140 and move second valve 152 to open position 114. In open position 114, pump piston 136 moves fluid 24 from pump bore 148, through casing end 149, and into casing bore 32 for future processing.

Motor controller 42 (shown in FIG. 1) sends current signal 118 (FIG. 9) to stator 72. Current signal 118 flows along track 74 and through magnetic windings 78. A resultant magnetic field (not shown) interacts with permanent magnet 88 and magnetic windings 78 to move motor shaft 82 within motor bore 70 from first motor end 60 to second motor end 62 and second position 130. In second position 130, pump piston 106 is configured to push first valve 108 from first pump end 92 to second pump end 94 and to closed position 115. Pump piston 106 moves fluid 24 within pump bore 102 toward casing bore 32. Moreover, pump piston 106 is configured to move second valve 110 to open position 114. In open position 114, pump piston 106 moves fluid 24 from pump bore 102, through second pump end 94, and into to casing bore 33 for future processing as previously described. In the exemplary embodiment, casing bore 32 and casing bore 33 may be coupled in flow communication with each other through a common connection 35 such as, but not limited to, a T-connection, a bushing connection, and a valve. Alternatively, casing bore 32 and casing bore 33 may independently connect to string 52 (shown in FIG. 1) and/or wellhead 16 (shown in FIG. 1).

Moreover, in second position 130, pump piston 136 is configured to draw fluid 24 from geological formation 22, through perforations 38, through channel 107, and into pump bore 148 as previously described. In second position 130, first valve 150 is moved to open position 114 and configured to prevent flow of fluid 24 from pump bore 148 and into motor bore 70. Moreover, in second position 130, second valve 152 is moved to closed position 115 to prevent flow of fluid 24 from casing bore 32 and into pump bore 148.

FIG. 10 is a cross-sectional side view of a pumping system 154 in first position 128. FIG. 11 is a cross-sectional side view of pumping system 154 in second position 130. In FIGS. 10 and 11, similar components shown in FIGS. 1-9 include the same element numbers as components shown in FIGS. 1-9. In the exemplary embodiment, stator 72 includes primary magnet assembly 122 having permanent magnet 88. Alternatively, primary magnet assembly 72 may include at least one of a plurality of magnetic windings, an induction cage, a magnetically permanent material having a magnetic flux pathway such as, but not limited to, a synchronous reluctance configuration and a switched reluctance configuration. Moreover, motor shaft 82 includes secondary magnet assembly 124 having magnetic windings 78. Pumping system 154 also includes pump 132 coupled to linear motor 18. Pump 132 includes pump housing 134 and pump piston 136. Pump housing 134 includes first pump end 138, second pump end 140, and pump body 142. Pump body 142 includes outer surface 144 and inner surface 146 defining pump bore 148. First pump end 138 is coupled to first motor end 60. Second pump end 140 is coupled to well casing end 149. In the exemplary embodiment, coupler 104 couples the pump housing 134 to motor housing 58. Moreover, perforations 38 are coupled in flow communications to geological formation 22 and pump bore 148. Seal assembly 40 includes first valve 150 and second valve 152 coupled to second pump end 140.

During the exemplary operation, motor controller 42 (shown in FIG. 1) sends current signal 125 to motor shaft 82. Current signal 125 flows along motor shaft 82 and through magnetic windings 78. A resultant magnetic field (not shown) interacts with permanent magnet 88 and magnetic windings 78 to move motor shaft 82 within motor bore 70 from second motor end 62 and first motor end 60. In first position 128, pump piston 106 is configured to draw fluid 24 from geological formation 22, through perforations 38, through channel 107, and into pump bore 102 as previously described. In first position 128, first valve 108 is configured to move to open position 114. Seal 121 prevents flow of fluid 24 from pump bore 102 and into motor bore 70. Moreover, in first position 128, second valve 110 is moved to closed position 115 to prevent flow of fluid 24 from casing bore 32 and into pump bore 102.

Moreover, in first position 128, motor shaft 82 is configured to move pump piston 136 into pump bore 148. Pump piston 136 is configured to push first valve 150 from first pump end 138 to second pump end 140 to closed position 115. Pump piston 136 further moves fluid 24 within pump bore 148 toward casing bore 32. Pump piston 136 is configured to move fluid 24 through second pump end 140 and move second valve 152 to open position 114. In open position 114, pump piston 136 moves fluid 24 from pump bore 148 to casing bore 32 for future processing.

Motor controller 42 (shown in FIG. 1) sends current signal 127 (FIG. 11) to stator 72. Current signal 127 flows along motor shaft 82 and through magnetic windings 78. A resultant magnetic field (not shown) interacts with permanent magnet 88 and magnetic windings 78 to move motor shaft 82 within motor bore 70 from first motor end 60 to second motor end 62 and second position 130. In second position 130, pump piston 106 is configured to push first valve 108 from first pump end 92 to second pump end 94 and to closed position 115. Pump piston 106 moves fluid 24 within pump bore 102 toward casing bore 32. Moreover, pump piston 106 is configured to move second valve 110 to open position 114. In open position 114, pump piston 106 moves fluid 24 from pump bore 102 to casing bore 32 for future processing.

Moreover, in second position 130, pump piston 136 is configured to draw fluid 24 from geological formation 22, through perforations 38, through channel 107, and into pump bore 148 as previously described. In second position 130, first valve 150 is moved to open position 114. Seal 121 prevents flow of fluid 24 from pump bore 148 and into motor bore 70. Moreover, in second position 130, second valve 152 is moved to closed position 115 to prevent flow of fluid 24 from casing bore 32 and into pump bore 148.

FIG. 12 is a flowchart illustrating an exemplary method 1200 of assembling a pumping system, such as pumping system 12 (shown in FIG. 3). Method 1200 includes coupling 1202 stator 72 (shown in FIG. 3), to motor housing 58 (shown in FIG. 3). The stator includes a primary magnet assembly, such as primary magnet assembly 76 (shown in FIG. 3). In the exemplary method 1200, assembling the primary magnet assembly includes coupling a plurality of magnetic windings 78 (shown in FIG. 4), to a track 74 (shown in FIG. 4), of the stator. A motor shaft 82 (shown in FIG. 3), is coupled 1204 to the stator. The motor shaft includes a secondary magnet assembly, such as secondary magnet assembly 86 (shown in FIG. 3). In the exemplary method 1200, assembling the secondary magnet assembly includes coupling a permanent magnet 88 (shown in FIG. 4), to the motor shaft. The motor shaft further includes a first diameter D1 (shown in FIG. 4).

Method 1200 includes coupling 1206 a pump housing 90 (shown in FIG. 4), to the motor housing. Method 1200 further includes coupling 1208 a pump piston 106 (shown in FIG. 4), to the motor shaft. The pump piston has a second diameter D2 (shown in FIG. 4), which is less than the first diameter. The pump piston is configured to reciprocate within the pump housing between a first position 54 (shown in FIG. 4), to a second position 56 (shown in FIG. 5). Method 1200 further includes coupling 1210 a seal assembly 40 (shown in FIG. 4), to the motor housing and the piston housing, wherein the seal is configured to seal the pump housing when the pump piston is in the second position and seal the motor housing when the pump piston is in the first position.

FIG. 13 is a cross-sectional view of a pump piston 156 and a valve 158 for use with pumping system 12 (shown in FIG. 1). Alternatively, pump piston 156 and valve 158 can be used with any of pumping systems shown in FIGS. 1-11. Valve 158 includes a first seat 160, a second seat 162, and valve device 164 removably coupled thereto. Valve device 164 includes a one-way flow valve such as, but not limited to, a ball check valve, a swing check valve, and a diaphragm check valve. First seat 160 and second seat 162 are coupled to pump piston 156 by a fastener 166 such as, but not limited to, a flange, a weld, and an arm. Moreover, first seat 160 and second seat 162 include grooves 168 which are configured to hold a seal 170, for example O-rings.

First seat 160, second seat 162, and pump piston 156 are configured to define a channel 172 therein. In the exemplary embodiment, channel 172 includes a first channel portion 174 and a second channel portion 176. First channel portion 174 includes at least one end 178 in flow communication with well casing 26 (shown in FIG. 1) and/or perforations 38 (shown in FIG. 1). First channel portion 174 is also coupled in flow communication with second channel portion 176 at an angle 180 having a range from about 0° to about 90°. Alternatively, angle 180 may include any range to enable pump system 12 to function. Second channel portion 176 is in flow communication with piston bore 102. The angular orientation of first channel portion 174 and second channel portion 176 facilitate directing flow of fluid 24 (shown in FIGS. 4-11) from perforations 38, through channel portions 174, 176, and into piston bore 102.

FIG. 14 is a cross-sectional view of a pump piston 182 and a valve 184. In FIG. 14, similar components have similar element numbers as shown in FIG. 13. Pump piston 182 and valve 184 can be used with any of pumping systems shown in FIGS. 1-11. Valve 184 includes first seat 160, second seat 162, and valve device 164 removably coupled thereto. Valve device 164 includes a one-way flow valve such as, but not limited to, a ball check valve, a swing check valve, and a diaphragm check valve. First seat 160 and second seat 162 are coupled to pump piston by fastener 166 such as, but not limited to, a flange, a weld, and an arm. Moreover, first seat 160 and second seat 162 include grooves 168 which are configured to hold seal 170, for example O-rings.

First seat 160, second seat 162, and pump piston 182 are configured to define a channel 186 therein. In the exemplary embodiment, channel 186 includes a first channel portion 188 and a second channel portion 190. First channel portion 188 includes at least one end 192 in flow communication with well casing 26 (shown in FIG. 1) and/or perforations 38 (shown in FIG. 1). First channel portion 188 is also coupled in flow communication with second channel portion 190 at an angle 194 having a range from about 0° to about 45°. Alternatively, angle 198 may include any range to enable pump system 12 to function. Second channel portion 190 is in flow communication with piston bore 102 (shown in FIGS. 4-11). The angular orientation of first channel portion 188 and second channel portion 190 facilitate directing flow of fluid 24 (shown in FIGS. 4-11) from perforations 38, through channel portions 188, 190, and into piston bore 102.

FIG. 15 is a cross-sectional view of a pump piston 196 and a valve 198 for use with pumping system 12 (shown in FIG. 1). Pump piston 196 and valve 198 can be used with any of pumping systems shown in FIGS. 1-11. Valve 198 includes first seat 160, second seat 160, and valve device 169 removably coupled thereto. Valve device 169 includes a one-way flow valve such as, but not limited to, a ball check valve, a swing check valve, and a diaphragm check valve. Moreover, first seat 160 and second seat 162 include grooves 168 which are configured to hold seal 170, for example O-rings. First seat 160, second seat 162, and pump piston 196 are configured to define a channel 200 therein.

FIG. 16 is a cross-sectional view of an alternative pumping system 202 in first position 54. FIG. 17 is a cross-sectional view of pumping system 202 in second position 56. In FIGS. 16 and 17, similar components showed in FIGS. 1-15 include the same element numbers shown in FIGS. 1-15. More particularly, pumping system 202 includes similar components shown in FIGS. 4 and 5. Alternatively, pumping system 202 may include similar components shown in FIGS. 6-15. Pumping system 202 may work with any system shown in FIGS. 1-15.

In the exemplary embodiment, motor 82 includes a motor channel 204 disposed within motor body 84. Moreover, pump 20 includes a pump channel 206 disposed within pump piston 106. Pump channel 206 is coupled in flow communication to channel 107 of first valve 108 and in flow communication to motor channel 204. Motor channel 204 is coupled in flow communication to a flow device 208 such as, but not limited to, a conduit, a pipe, a groove, a sleeve, a channel, and a casing. Flow device 208 is coupled in flow communication to formation 22 via perforations 38.

In first position 54 (FIG. 4), motor shaft 82 is configured to move pump piston 106 into motor bore 70. Pump piston 106 is configured to draw fluid 24, under a first piston pressure P1, from geological formation 22, through perforations 38, and into channel 107. More particularly, first piston pressure P1 induces flow of fluid 24 from formation 22, through flow device 208, and into motor channel 204 and piston channel 206. First piston pressure P1 in channel 107 induces valve device 105 to move to an open position 114, represented by hash lines within valve 108. More particularly, in open position 114, valve device 105 is decoupled from first seat 101 and second seat 103 to facilitate flow of fluid 24 from perforations 38, through channels 107, 204, and 206, and into piston bore 102. In first position 54, first piston pressure P1 in pump bore 102 is less than casing pressure CP of fluid 24 located in casing bore 32. Based at least on the pressure differential between first piston pressure P1 and casing pressure CP, casing pressure CP induces second valve 110 to move to closed position 115. More particularly, in closed position 115, valve device 113 is coupled to first seat 109 and second seat 111 and configured to seal pump bore 102 from casing bore 32. Moreover, in closed position 115, valve device 113 prevents fluid 24 in casing bore 32 from entering pump bore 102 and prevents fluid 24 in pump bore 102 from entering casing bore 32.

In second position 56 (FIG. 17), motor shaft 82 is configured to move pump piston 106 into pump bore 102. Pump piston 106 is configured to move first seat 101, second seat 103, and channel 107 to closed position 115. More particularly, in closed position 115, valve device 105 is coupled to first seat 101 and second seat 103 and configured to seal pump bore 70 from piston bore 102. Moreover, in closed position 115, valve device 105 seals channel 107 from piston bore 102 to prevent flow of fluid 24 from perforations, 38, through channel 107, and into piston bore 102. Moreover, pump piston 106 is configured to apply second piston pressure P2 to fluid 24 within pump bore 102 as pump piston 106 moves first valve 108 from first pump end 92 and toward second pump end 94 and to closed position 115.

Second piston pressure P2 is greater than casing pressure CP of fluid 24 present in casing bore 32. Based at least on pressure differences between second piston pressure P2 and casing pressure CP, second piston pressure P2 induces second valve 110 to move to open position 114. More particularly, in open position 114, valve device 113 is decoupled from first seat 109 and second seat 111 to facilitate movement of fluid 24 from pump bore 102, through second pump end 94, and into casing bore 32 for future processing. Subsequent the discharge of fluid 24 from pump bore 102 and into casing bore 32, motor shaft 82 is configured to move pump piston 106 out of pump bore 102 and into motor bore 70.

FIG. 18 is a cross-sectional view of an alternative pumping system 210. In FIG. 18, similar components showed in FIGS. 1-17 include the same element numbers shown in FIGS. 1-17. More particularly, pumping system 210 includes similar components shown in FIGS. 4 and 5. Alternatively, pumping system 210 may include similar components shown in FIGS. 6-17. Pumping system 202 may work with any system shown in FIGS. 1-17.

In the exemplary embodiment, pumping system 210 includes a heat transfer device 212 coupled in flow communication to formation 22 via perforations 38 and in flow communication to piston bore 102. Heat transfer device 212 includes devices such as, but not limited to, a conduit, a pipe, a groove, a sleeve, a channel, and a casing. Heat transfer device 212 is further coupled in flow communication to motor housing 58. For illustrative purposed only, Heat transfer device 212 is shown coupled adjacent to an upper portion of motor housing 58. Alternatively, Heat transfer device 212 may be coupled to any portion of motor housing 58. Heat transfer device 212 is configured to direct fluid 24 from formation 22, through perforations 38 and into piston bore 102. More particularly, Heat transfer device 212 is configured to direct fluid 24 adjacent and/or in contact with motor housing 58 to facilitate heat transfer from motor housing 58 and into fluid 24. Accordingly, fluid 24 present within flow device 212 facilitates heat transfer from motor housing 58 to facilitate cooling motor 18.

The exemplary embodiments described herein provide for a submersible linear motor and pump for cost effective pumping of production fluids from a well. The exemplary embodiments described positively displace a production fluid at different production rates, such as, but not limited to, a high rate of fluid production in the early phase of the well life and a lower rate of fluid production for the remainder of the well life due to lower levels of available production fluid. Moreover, the exemplary embodiments reduce interference and enhance electromagnetic performance of a pumping system by removing seals and/or encapsulation material between a motor shaft and motor stator which reduces a space between the motor shaft and the motor stator.

The exemplary embodiments described herein locate a pump housing outboard of a motor housing to facilitate sizing a pump piston less than a motor shaft to provide more surface area for magnetic forces in the linear motor to act upon the motor shaft which reduces a length of the linear motor. Moreover, the exemplary embodiments provide a linear motor having a motor shaft with a permanent magnet and a stator having magnetic windings wherein the permanent magnet supports the magnetic windings during motor operations which enhances motor life. Further, the exemplary embodiments described herein provide a linear motor having a motor shaft with a plurality of magnetic windings and a stator having a permanent magnet wherein the linear motor provides for convenient and efficient removal of magnetic windings with reduced or no interference from the permanent magnet. Still further, the exemplary embodiments described herein facilitate pumping of production fluids at precise dynamic rates by controlling the electronic actuation of a linear motor. The exemplary embodiments describe herein seal a motor bore from production fluids to facilitate small tolerances between a motor shaft and a motor stator. The exemplary embodiments described herein can operate in a push configuration and/or a pull configuration wherein valve devices can be positioned on either side of valve seats and/or positioned in pump bores or casing bores.

A technical effect of the systems and methods described herein includes at least one of: (a) positively displacing a production fluid by a reciprocating pump driven by a linear motor; (b) reducing an axial length of a linear motor; (c) pumping multiphase fluids at precise dynamic rates by controlling the electronic actuation of a linear motor; (d) locating a pump housing outboard of a motor housing to facilitate sizing a pump piston different than a motor shaft to optimize a flow rate and a pressure capacity; (e) providing stationary support to stator windings during pumping operations; (f) facilitating convenient and efficient removal of magnetic windings with reduced or no interference from a permanent magnet; (g) sealing a motor bore from fluids to facilitate small tolerances between a motor shaft and a motor stator; and (h) decreasing design, installation, operational, maintenance, and/or replacement costs for a pumping system for a well site.

Exemplary embodiments of a pumping system and methods for assembling a pumping are described herein. The methods and systems are not limited to the specific embodiments described herein, but rather, components of systems and/or steps of the methods may be utilized independently and separately from other components and/or steps described herein. For example, the methods may also be used in combination with other manufacturing systems and methods, and are not limited to practice with only the systems and methods as described herein. Rather, the exemplary embodiment may be implemented and utilized in connection with many other fluid and/or gas applications.

Although specific features of various embodiments of the invention may be shown in some drawings and not in others, this is for convenience only. In accordance with the principles of the invention, any feature of a drawing may be referenced and/or claimed in combination with any feature of any other drawing.

This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.

Claims

1. A pumping system for use in moving a fluid present within a wellbore, said pumping system comprising:

an electric linear motor comprising: a motor housing; a stator coupled to said motor housing and comprising a track having a primary magnet assembly; and a motor shaft electrically coupled to said stator and comprising a body having a secondary magnet assembly and a first diameter;

a first pump coupled to said electric linear motor, said pump comprising: a pump housing coupled to said motor housing; and a pump piston coupled to said motor shaft and having a second diameter which is different than said first diameter, said pump piston configured to reciprocate within said pump housing between a first position and a second position; and

a seal coupled to said motor housing and said pump housing and configured to direct the fluid into said pump housing when said pump piston is in said first position and to direct the fluid out of said pump housing when said pump piston is in said second position.

2. The pumping system of claim 1, wherein said primary magnet assembly comprises at least one of a plurality of magnetic windings and a permanent magnet.

3. The pumping system of claim 1, wherein said secondary magnet assembly comprises at least one of a plurality of permanent magnetic windings and a permanent magnet.

4. The pumping system of claim 1, wherein said motor housing has a first length and said pump housing has a second length which is less than said first length.

5. The pumping system of claim 1, wherein said housing comprises an inner surface coupled to said track.

6. The pumping system of claim 1, wherein said first diameter is larger than said second diameter.

7. The pumping system of claim 1, wherein said seal comprises a channel coupled in flow communication to the wellbore and said pump housing.

8. The pumping system of claim 1, further comprising a motor channel and a pump channel.

9. The pumping system of claim 1, further comprising a connector removably coupled to at least one of said motor housing and said pump housing.

10. The pumping system of claim 1, further comprising another pump coupled to said motor shaft.

11. A well assembly for pumping a fluid, said well assembly comprising:

a well casing comprising a first zone, a second zone and a plurality of perforations coupled in flow communication to said second zone;

an electric linear motor coupled to said well casing in at least one of said first zone and said second zone and comprising: a motor housing; a stator coupled to said motor housing and comprising a track having a primary magnet assembly; and a motor shaft electrically coupled to said stator and comprising a body having a secondary magnet assembly and a first diameter;

a pump coupled to said electric linear motor and located within said second zone, said pump comprising: a pump housing coupled to said motor housing; and a pump piston coupled to said motor shaft and having a second diameter which is less than said first diameter, said pump piston configured to reciprocate within said pump housing between a first position and a second position; and

a seal coupled to said motor housing and said pump housing and configured to direct the fluid into said pump housing when said pump piston is in said first position and to direct the fluid out of said pump housing when said pump piston is in said second position.

12. The well assembly of claim 11, wherein said motor housing has a housing length and said pump housing has a pump length which is less than said housing length.

13. The well assembly of claim 11, wherein said primary magnet assembly comprises a magnetic winding and said secondary magnet assembly comprises a permanent magnet.

14. The well assembly of claim 11, wherein said primary magnet assembly comprises a permanent magnetic material and wherein said secondary magnet assembly comprises a plurality of magnetic windings.

15. The well assembly of claim 11, further comprising a heat transfer device coupled to said motor housing.

16. A method of assembling a pumping system, the method comprising:

coupling a stator to a motor housing, the stator comprising a primary magnet assembly;

coupling a motor shaft to the stator, the motor shaft comprising a secondary magnet assembly and having a first diameter;

coupling a pump housing to the motor housing;

coupling a pump piston to the motor shaft, the pump piston having a second diameter which less than the first diameter and configured to reciprocate within the pump housing between a first position and a second position; and

coupling a seal to the motor housing and the piston housing, the seal configured to direct the fluid into the pump housing when the pump piston is in the first position and to direct the fluid out of the pump housing when the pump piston is in the second position.

17. The method of claim 16, further comprising coupling a plurality of magnetic windings to a track of the stator.

18. The method of claim 16, further comprising coupling a permanent magnet to the motor shaft.

19. The method of claim 16, further comprising coupling a permanent magnet to a track of the stator.

20. The method of claim 16, further comprising coupling a plurality of magnetic windings to the motor shaft.