Assisted lift electrical subsurface VANE pump system

Abstract

A well installation (15) comprising a motor (40) and a vane pump (50) in a housing (31) arranged in the well, the vane pump comprising an entry port plate (70) having an inlet port (75, 76) connected to a pump inlet of the housing, an exit port plate (80) having an outlet port (85, 86) connected to a pump outlet of the housing, a cam ring (90), a pump shaft (55) coupled to the motor, a rotor (60) coupled to the pump shaft and comprising a plurality of circumferentially spaced vane slots (65), and a plurality of vanes (51) slidingly supported in the vane slots and operatively configured to extend radially between an outer radial surface of the rotor and an opposed inner radial surface of the cam ring, wherein the motor is operatively driven to pump a production fluid from the inlet to the outlet through the vane pump.

Description

ASSISTED LIFT ELECTRICAL SUBSURFACE VANE PUMP SYSTEMTECHNICAL FIELD

[0001] The presently disclosed subject matter relates generally to the field of oil and gas wells, and more particularly to a subsurface pump system.BACKGROUND ART

[0002] Often there is not enough pressure for wells to produce at commercially viable levels without assistance in lifting formation fluids to the surface. Artificial lift devices are therefore used to pump oil or other liquids from underground or subsurface to ground or surface level.

[0003] A common approach for moving production fluids to the surface includes the use of a submersible pump. These pumps are installed in the well itself, typically at the lower end of the production tubing. One type of such a submersible pump generally comprises a cylindrical housing and an inner reciprocating piston, which reside at the base of the production line. The pump has an inlet at the bottom end of the piston and an outlet at the top end. The pump forces a first volume of fluid upward within the production tubing during an upstroke and a second volume of fluid upward within the tubing during the pump’s downstroke. The piston is reciprocated axially within the well bore by a linear magnetic motor. The linear magnetic motor having a series of windings that act upon an inner shaft is located below the pump. The motor is powered by an electrical cable extending from the surface to the bottom of the well. The power supply generates a magnetic field within the coils of the motor which, in turn, imparts an oscillating force on the shaft of the motor. The shaft thereby is translated in an up and down or linear fashion within the well. The shaft is connected, through a linkage, to the piston of the pump and thus imparts translational or lineal movement to the pump piston. The linear electric motor thus enables the piston of the pump to reciprocate vertically, thereby enabling fluids to be lifted with each stroke of the piston towards the surface of the well.

[0004] U.S. Patent No. 1,655,825, which issued Jan 10, 1928, discloses a linear electromagnetic motor coupled to an oil w ell pump. Solenoids are mounted within a casing and arranged to actuate a core. The core is made up of a stacked series of magnetizable members interspersed between non-magnetizable members. The core is coupled to a pump plunger. An upper valve and two lower valves allow only upwards flow of fluid. By sequentially applying current to the elevating solenoids, and then the depressing solenoids, the core and pump plunger are caused to reciprocate, which forces fluid to flow upwards through the valves.

[0005] U.S. Patent No. 5,049,046 teaches a down hole electromagnetic motor-pump assembly having an armature with permanent magnets and a stator with multiple coils, a pump having a reciprocating piston, a down hole switching motor controller, and a remote wireless monitoring station. The patent teaches a motor-pump assembly having a motor-pump cartridge unit that is supported down hole in a sleeve assembly of an oil well and connected to the surface through tubing and a cable. The pump is shown and described as having an outer barrel that contains a piston within. A check valve is arranged below the piston and a second check valve is arranged above the piston.

[0006] U.S. Patent No. 5,831,353 discloses a motor-pump assembly having a pump and a brushless DC linear motor for driving the pump reciprocatively to allow- the fluids in the production tube to be lifted to the upper ground level. A motor controller is provided for controlling the linear motor and supplies the motor with a certain number of direct current pulses. A coupling arrangement connects the pump to the motor. The motor is described as being of modular construction with a plurality7of interconnected stator modules or units and at least one modular cylindrically shaped mover. The stator units are described as having a plurality of spaced apart pairs of oppositely wound toroidal coils. The mover is described as having ring shaped, radially polarized permanent magnets stacked on a shaft in alternating polarities interleaved with bearing units, which share the total frictional stress by being spaced between the respective magnets. The pump is described as working much like a sucker rod pump and has a plunger coupled to the motor mover so as to move together in unison. Well fluid is pumped through a bore in the center of motor, thus enabling much of the heat generated by the motor to be dissipated into the well fluid.BRIEF SUMMARY

[0007] With parenthetical reference to the corresponding parts, portions or surfaces of the disclosed embodiment, merely for purposes of illustration and not by way of limitation, a well installation (15) is provided comprising: tubing (17) arranged in a well (18) and forming a flow channel to a surface level for fluids originating from below the surface level; a motor pump housing (31, 231) disposed in the well; a motor (40) disposed in the housing and comprising a motor shaft (43) configured to rotate about a motor axis; a pump inlet (38) and a pump outlet (39) in the housing; a vane pump (50, 250) disposed in the housing between the pump inlet and the pump outlet; the vane pump comprising: an entry7port plate (70, 270) supported by the housing and having an inlet port (75, 76, 275, 276) connected to the pump inlet; an exit port plate (80, 280) supported by the housing and having an outlet port (85, 86, 285, 286) connected to thepump outlet; a cam ring (90, 290) supported by the housing and disposed axially between the entry port plate and the exit port plate; a pump shaft (55, 255) orientated about a shaft axis and rotationally coupled to the motor shaft; a rotor (60, 260) rotationally coupled to the pump shaft and disposed axially between the entry port plate and the exit port plate; the rotor and the cam ring forming a pumping volume (100, 200) disposed radially between an outer radial surface of the rotor and an opposed inner radial surface of the cam ring and axially between the entry port plate and the exit port plate; the rotor comprising a plurality of circumferentially spaced vane slots (65, 265); and a plurality of axially-extending vanes (51, 151 , 251) slidingly supported in the respective vane slots of the rotor and operatively configured to extend radially between the outer radial surface of the rotor and the opposed inner radial surface of the cam ring; wherein the motor is operatively driven to pump a production fluid from the inlet to the outlet through the vane pump.

[0008] The vane pump may comprises a first stage (250a) and a second stage (250b); the first stage may comprises the rotor (60) rotationally coupled to the pump shaft (255) and having the plurality of circumferentially spaced vane slots (65), the cam ring (90) supported by the housing (233), the plurality of vanes (51) slidingly supported in the respective vane slots of the rotor, the entry port plate (70) supported by the housing and having an inlet port (75, 76) connected to the pump inlet (38), and the exit port plate (80) supported by the housing and having an outlet port (85, 86); the second stage may comprise a second rotor (260) rotationally coupled to the pump shaft and having a second plurality of circumferentially spaced vane slots (265), a second cam ring (290) supported by the housing, a second plurality of vanes (251) slidingly supported in the respective vane slots of the second rotor, a second entry port plate (270) supported by the housing and having an inlet port (275, 276) connected to the outlet port of the exit port plate of the first stage, and a second exit port plate (280) supported by the housing and having a second outlet port (285, 286) connected to the pump outlet; the second stage may be operatively configured in series with the first stage; and the motor may be operatively driven to pump the production fluid from the inlet to the outlet in series through the first stage and the second stage.

[0009] The entry port plate, the exit port plate, the rotor, the cam ring, and the vanes may each have a Rockwell C scale hardness greater than 70 HRc. The entry port plate, the exit port plate, the rotor, the cam ring, and the vanes may each comprise tungsten carbide. The entry port plate, the exit port plate, the rotor, the cam ring, and the vanes may each comprise a sintered metal, a hybrid powder and / or a ceramic. The sintered metal, hybrid powder and / or ceramic may be selected from a group consisting of tungsten carbide, silicon carbide, chromium carbide, siliconnitride, boron nitride, aluminum oxide, a cobalt-based chromium and tungsten alloy, an alumina ceramic, and a zirconia ceramic.

[0010] The entry port plate may comprise an annular output face (72) orientated perpendicular to the shaft axis; the rotor may comprise an annular input end face (61) axially opposed to the annular output face of the entry' port plate; the entry' port plate and the rotor may comprise an axial rotor entry clearance (101a) between the annular output face of the entry port plate and the annular input end face of the rotor; the exit port plate may comprise an annular input face (81) orientated perpendicular to the shaft axis; the rotor may comprise an annular output end face (62) axially opposed to the annular input face of the exit port plate; the rotor and the exit port plate may comprise an axial rotor exit clearance (102a) between the annular output end face of the rotor and the annular input face of the exit port plate; the shaft may comprise an external shaft spline (56) having a plurality of axially extending external shaft spline teeth (57), each of the shaft spline teeth comprising a circular shaft spline tooth thickness (57a); the rotor may comprise an internal rotor spline (66) in engagement with the external shaft spline and having plurality' of axially extending internal rotor spline slots (68), each of the rotor spline slots comprising a circular internal spline space width (68a); and the circular internal spline space width of the internal rotor spline slots may be greater than the circular shaft spline tooth thickness of the shaft spline teeth to provide a maximum rotor-to-shaft outer axial offset tolerance (130); and a sum of the axial rotor entry clearance and the axial rotor exit clearance may be less than the maximum rotor-to-shaft outer axial offset tolerance. The maximum rotor-to-shaft outer axial offset tolerance may be at least ten percent greater than the sum of the axial rotor entry' clearance and the axial rotor exit clearance.

[0011] The inlet port of the entry port plate may comprise an axially extending, circumferentially positioned, arcuate first inlet port (75, 275) connected to the pump inlet; and the inlet port of the entry port plate may comprise an axially extending, circumferentially positioned, arcuate second inlet port (76, 276) connected to the pump inlet. The outlet port of the exit port plate may comprise an axially extending, circumferentially positioned, arcuate first outlet port (85, 285) connected to the pump outlet; and the outlet port of the exit port plate may comprise an axially extending, circumferentially positioned, arcuate second outlet port (86, 286) connected to the pump outlet. The first inlet port may be circumferentially spaced apart from the second inlet port by about 180 degrees; and the first outlet port may be circumferentially spaced apart from the second outlet port by about 180 degrees.

[0012] The vanes may have a maximum transverse thickness (52, 152) through the pumping volume and may be operatively configured to divide the pumping volume into a leading pumpingchamber (99) on a leading axially extending side (99a. 199a) of the vanes and a trailing pumping chamber (98) on a trailing axially extending side (98a, 198a) of the vanes between the entry’ port plate and the exit port plate; the exit port plate may comprise an annular input face (81, 281) orientated perpendicular to the shaft axis and an annular output face (82, 282) orientated perpendicular to the shaft axis; the outlet port of the exit port plate may comprise an axially- extending, circumferentially positioned, arcuate first outlet port (85, 285) in fluid communication with the pumping volume and formed by a through-surface (85 a) extending between the annular input face and the annular output face; the through-surface may have a leading axially-extending circumferential end (85b) and a trailing axially-extending circumferential end (85c); the exit port plate may comprise a pressure relief groove (87) in the annular input face extending circumferentially from the through-surface proximate to the trailing axially-extending circumferential end to a trailing circumferential pressure relief end (87a); and the pressure relief groove may have a circumferential length (89a) between the through-surface and the trailing circumferential pressure relief end that is greater than the maximum transverse thickness of the vanes; whereby the pressure relief groove may provide a pressure connection between the leading pumping chamber on the leading axially extending side of the vanes and the trailing pumping chamber on the trailing axially extending side of the vanes. The outlet port of the exit port plate may comprise an axially-extending, circumferentially positioned, arcuate second outlet port (86, 286) in fluid communication with the pumping volume and formed by a second through-surface (86a) extending between the annular input face and the annular output face; the second through- surface may have a second leading axially-extending circumferential end (86b) and a second trailing axially-extending circumferential end (86c); the exit port plate may comprise a second pressure relief groove (88) in the annular input face extending circumferentially from the second through-surface proximate to the second trailing axially-extending circumferential end to a second trailing circumferential pressure relief end (88a); and the second pressure relief groove may have a second circumferential length (89b) between the second through-surface and the second trailing circumferential pressure relief end that is greater than the maximum transverse thickness of the vanes; whereby the second pressure relief groove provides a second direct pressure connection between the leading pumping chamber on the leading axially extending side of the vanes and the trailing pumping chamber on the trailing axially extending side of the vanes.

[0013] The exit port plate may comprise an annular input face (81, 281) orientated perpendicular to the shaft axis; the outlet port of the exit port plate may comprise a first outlet port (85, 285); the rotor may comprise an annular output end face (62, 262) axially opposed to the annular input face of the exit port plate; each of the vane slots of the rotor may comprise a blind end (69); theexit port plate may comprise an arcuate fluid bearing groove (113, 114) in the annular input face; the arcuate fluid bearing groove may be positioned radially opposite the annular output end face of the rotor and radially inwards from the blind ends of the vane slots of the rotor; and a fluid channel (110, 110, 112) may extend between the annular fluid bearing groove and the first outlet port. The exit port plate may comprise an annular output face (82, 282) orientated perpendicular to the shaft axis; the fluid channel may comprise an annular distribution groove (112) in the input face of the exit port plate; and the fluid channel may comprise a through-hole (110, 111) in the exit port plate extending between the annular output face and the annular distribution groove. The arcuate fluid bearing groove may comprise a first arcuate bearing groove portion (113) having a first groove inlet in fluid communication with the annular distribution groove at a first circumferential junction (113a) and a second arcuate bearing groove portion (114) having a second groove inlet in fluid communication with the annular distribution groove at a second circumferential junction (114a). The first groove inlet may be circumferentially spaced apart from the second groove inlet by about 180 degrees.

[0014] The exit port plate may comprise an annular input face (81, 281) orientated perpendicular to the shaft axis; the outlet port of the exit port plate may comprise a first outlet port (85, 285); the rotor may comprise an annular output end face (62, 262) axially opposed to the annular input face of the exit port plate; each of the vane slots of the rotor may comprise a blind end (69) having an axially extending undervane pressure groove (115) facing a rotor end (53, 153) of the respective vanes; the input face of the exit port plate may comprise an annular distribution groove (112) in fluid communication with the undervane pressure grooves of the vane slots of the rotor; and a fluid channel (110, 111) may extend between the annular distribution groove and the first outlet port. The annular distribution groove may be radially aligned with the undervane pressure grooves. The exit port plate may comprise an annular output face (82, 282) orientated perpendicular to the shaft axis and the fluid channel may comprise a through-hole (1 10, 111) in the exit port plate extending between the annular output face and the annular distribution groove.

[0015] Each of the plurality of vanes (1 1) may be operatively configured to divide the pumping volume into a leading pumping chamber (99) on an axially extending leading side (199a) of the vanes and a trailing pumping chamber (98) on an axially extending trailing side (198a) of the vanes between the entry port plate and the exit port plate; each of the vanes may comprise an inner end portion (53, 153) and an outer end portion (154); the inner end portion of the vane may face a blind end (69) of one of the vane slots of the rotor; the outer end portion of the vane may face the inner radial surface of the cam ring; the outer end portion of the vane may comprise an axially extending leading edge (154a) on the leading side of the vane and an axially extendingtrailing edge (154b) on the trailing side of the vane; and the trailing edge of the outer end portion of the vane may be offset (154e) radially inwards relative to the leading edge of the outer end portion of the vane. The outer end portion may comprise an axially extending angled end surface (154c) between the leading edge and the trailing edge and the angled end surface may be orientated at an internal offset angle (154d) relative to the leading side of the vane of less than 85 degrees. The offset angle may be less than 75 degrees. The leading edge may be orientated on a radius ( 154r) between the leading side of the vane and the angled end surface of the vane. The inner portion of the vane may comprise an axially extending rounded end surface (153c) betw een the leading side and the trailing side and the rounded end surface may be orientated on a radius ( 153r) between the leading side and the trailing side.

[0016] The motor may comprise a stator (42) and a motor rotor (41) rotationally coupled to the motor shaft and configured and arranged to rotate relative to the stator under the effect of a magnetic field generated by the stator. The well installation may comprise a cable (24) supplying electric power from the surface level to the stator. The motor pump housing may comprise an actuator housing section (35) defining a first chamber substantially isolated from the well and the stator and the motor rotor may be disposed in the first chamber. The motor pump housing may comprise a pump housing section (33, 233) connected to the actuator housing section and the pump shaft may be connected to a portion of the motor shaft sealingly penetrating an end portion of the actuator housing section for rotational movement therewith. The motor pump housing may comprise a pump housing section (33, 233) and the pump may be disposed in the pump housing section and the motor pump housing may comprise an actuator housing section (35) and the motor may be disposed in the actuator housing section.BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings are incorporated herein as part of the specification. The drawings described herein illustrate embodiments of the presently disclosed subject matter and are illustrative of selected principles and teachings of the present disclosure. However, the draw ings do not illustrate all possible implementations of the presently disclosed subject matter and are not intended to limit the scope of the present disclosure in any way.

[0018] FIG. 1 is a schematic vertical sectional view of an embodiment of an oil-well installation with an improved actuator and pump system.

[0019] FIG. 2 is a front view of an embodiment of the actuator and pump system shown in FIG. 1.

[0020] FIG. 3A is a longitudinal sectional view' of the actuator and pump system shown in FIG. 2, taken generally on line A-A of FIG. 2.

[0021] FIG. 3B is a schematic longitudinal sectional view' of the actuator and pump system shown in FIG. 3A.

[0022] FIG. 4 is an enlarged longitudinal sectional view of the vane pump shown in FIG. 3.

[0023] FIG. 5 is an exploded perspective view of the vane pump shown in FIG. 4.

[0024] FIG. 6 is a longitudinal exploded sectional view of the vane pump shown in FIG. 4.

[0025] FIG. 7 is an enlarged longitudinal sectional view of the pump shaft and rotor shown in FIG.4.

[0026] FIG. 8 A is a transverse sectional view of the pump shaft and rotor shown in FIG. 7.

[0027] FIG. 8B is an enlarged partial transverse sectional view of the pump shaft and rotor shown in FIG. 8A.

[0028] FIG. 8C is an enlarged view of the splined tooth engagement between the pump shaft and rotor shown in FIG. 8B.

[0029] FIG. 9A is a bottom isometric view of the low er port plate shown in FIG. 5.

[0030] FIG. 9B is a bottom plan view of the inlet end face of the lower port plate shown in FIG. 9A.

[0031] FIG. 9C is a top plan view of the outlet end face of the low er port plate shown in FIG. 9A.

[0032] FIG. 10A is a bottom isometric view of the upper port plate shown in FIG. 5.

[0033] FIG. 10B is a bottom plan view of the inlet end face of the upper port plate shown in FIG. 10A.

[0034] FIG. 10C is atop plan view of the outlet end face of the upper port plate shown in FIG. 10A.

[0035] FIG. 11 A is a first partial exploded partial cutaw ay view of the vane pump shown in FIG. 4.

[0036] FIG. 1 IB is a second partial cutaway view' of the vane pump shown in FIG. 4.

[0037] FIG. 12 is an enlarged view of the groove connection shown in FIG. 11 A, taken generally within the indicated area B of FIG. 11A.

[0038] FIG. 13 is an enlarged view of the relief groove shown in FIG. 11A, taken generally within the indicated area C of FIG. 11A.

[0039] FIG. 14 is a transverse sectional view of the vane pump shown in FIG. 4 operative in a clockwise rotational direction.

[0040] FIGS. 15A-15D are enlarged and partial schematic views of the vane pump shown in FIG.14 with incremental rotation in the clockwise direction, taken generally within the indicated area D of FIG. 14.

[0041] FIG. 16 is an enlarged view of an alternative embodiment of the actuator and vane pump shown in FIG. 2.

[0042] FIG. 17 is a longitudinal sectional view of the actuator and vane pump shown in FIG. 16, taken generally on line E-E of FIG. 16.

[0043] FIG. 18 is a partial exploded view of the vane pump shown in FIG. 17.

[0044] FIG. 19 is an enlarged partial longitudinal sectional view of the vane pump shown in FIG. 17.

[0045] FIG. 20 is an alternative embodiment of the vanes shown in FIGS. 11 A, 11B, 14 and 15A- 15D.

[0046] FIG. 21 is a top side view of the vane shown in FIG. 20.

[0047] FIG. 22 is an enlarged view of the vane shown in FIG. 21, taken within the indicated area F of FIG. 21.DETAILED DESCRIPTION OF THE EMBODIMENTS

[0048] At the outset, it should be clearly understood that like reference numerals are intended to identify the same structural elements, portions or surfaces consistently throughout the several drawing figures, as such elements, portions or surfaces may be further described or explained by the entire written specification, of which this detailed description is an integral part. Unless otherwise indicated, the drawings are intended to be read (e.g., crosshatching, arrangement of parts, proportion, degree, etc.) together with the specification, and are to be considered a portion of the entire written description of this invention. As used in the following description, the terms "horizontal", "vertical", "left", "right", "up" and "down", as well as adjectival and adverbial derivatives thereof (e.g., "horizontally", " rightwar dly", "upwardly", etc.), simply refer to the orientation of the illustrated structure as the particular drawing figure faces the reader. Similarly, the terms "inwardly" and "outwardly" generally refer to the orientation of a surface relative to its axis of elongation, or axis of rotation, as appropriate.

[0049] It is to be understood that the specific assemblies and systems illustrated in the attached drawings and described in the following specification are simply exemplary7embodiments. Hence, specific dimensions, directions, or other physical characteristics relating to the embodiments disclosed are not to be considered as limiting, unless expressly stated otherwise in a claim. Also, although they may not be, like elements in various embodiments described herein may be commonly referred to with like reference numerals within this section of the application.

[0050] It is to be appreciated that the present teaching is by way of example only, not by limitation. The concepts herein are not limited to use or application with a specific system or method. Thus, although the instrumentalities described herein are for the convenience of explanation, shown and described with respect to exemplary' embodiments, it will be appreciated that the principles herein may be applied equally in other types of systems and methods involving pump systems.

[0051] Where they are used herein, the terms “first.” “second,” and so forth, do not necessarily denote any ordinal, sequential or priority relation, but are simply used to distinguish one element or set of elements more clearly from another element or set of elements, unless specified otherwise.

[0052] Referring now to the drawings, and more particularly to FIG. 1 , an oil well pump and electric motor system is provided, a first embodiment of which is generally indicated at 15. As shown, a well hole extends from the surface level to a point below ground. The well hole is lined with casing 16 to form well bore 18 that includes perforations providing fluid communication between well bore 18 and a hydrocarbon-bearing formation there around. Motor pump unit 30 is disposed at the bottom of well bore 18 and is provided to artificially lift production fluid from well bore 18 through tubing string 17 to a collection point at the surface.

[0053] Motor pump unit 30 is generally contained in cylindrical housing 31 and housing 31 generally comprises top manifold outlet section 32 connected to the downhole end of tubing string 17, pump housing section 33 containing vane pump 50 and positioned below top manifold outlet 32. pump-to-motor adapter housing section 34 positioned below pump housing section 33, motor housing section 35 positioned below adapter section 34 and containing motor 40, and bottom motor end cap 36.

[0054] In this embodiment, motor control and drive electronics for unit 30 are contained in controller cabinet 20 at the surface of well 18 and drive pow er is communicated by power cable 24, which extends from surface controller 20 at the surface of well 18 directly to power port 37 of housing 31 below the surface to drive motor 40. Pump system 15 thus generally comprises topside control and drive electronics 23 connected by cable 24 to downhole motor pump unit 30 and tubing string 17 extending topside from downhole motor pump unit 30.

[0055] Pump housing 31 includes pump inlet 38 in adapter section 34 for receiving production or well fluids, and pump outlet 39 in top manifold block 32 for outputting well fluids at a higher pressure than pump inlet 38. Pump housing 31 also includes power input connection 37 in adapter section 34 for inputting pow er to motor 40. Adapter section 34 with pump inlet 38 are disposed at the bottom end of pump housing section 33 and manifold block 32 with pump outlet 39 are disposed at the top end of housing 31. Accordingly, pump unit 30 forces a volume of fluid upward within production tubing 17.

[0056] With reference to the embodiment shown in FIGS. 3-15, single stage vane pump 50 is driven by motor 40, both of which are contained in cylindrical unit housing 31, with pump housing section 33 containing pump 50 and motor housing section 35 containing motor 40.

[0057] In this embodiment, motor 40 is a brushless D.C. variable-speed servo-motor that is supplied with a current. The speed and output of pump unit 50 is variable with variations in the speed of motor 40. Solid shaft 55 of pump 50 is rotationally coupled via extension shaft 45 to solid output shaft 43 of electric motor 40. Motor 40 has inner rotor 41 with permanent magnets and outer non-rotating stator 42 with coil windings. Stator 42 is fixed to motor housing section 35 such that stator 42 does not rotate relative to housing 31. When current is appropriately applied through the coils of stator 42, a magnetic field is induced. The magnetic field interaction between stator 42 and rotor 41 generates torque which may rotate output shaft 43. Accordingly, motor 40 will selectively apply a torque on shaft 43 about axis x-x at varying speeds.

[0058] As shown, vane pump 50 generally comprises lower port plate 70 supported by housing section 33. upper port plate 80 supported by housing section 33, cam ring 90 supported by housing section 33 and disposed axially between lower port plate 70 and upper port plate 80, pump shaft 55 orientated about shaft axis x-x and rotationally coupled to motor shaft 43 by shaft extension 45, pump rotor 60 rotationally coupled to pump shaft 55 and disposed axially between lower port plate 70 and upper port plate 80 and having a plurality of circumferentially spaced and axially extending vane slots 65. and a plurality of vanes 51 disposed axially between lower port plate 70 and upper port plate 80 and slidingly supported in the respective vane slots 65 of rotor 60 and operatively configured to extend radially between outer radial surface 64 of rotor 60 and opposed inner radial surface 93 of cam ring 90. Radially extending vanes 51 rotate in cam ring 90 when shaft 55 and rotor 60 are driven by connected motor 40. Vanes 51 may have variable lengths and are biased to maintain contact with ring 90 as pump shaft 55 rotates. Rotor 60 with circumferentially spaced vanes 51 radially bearing against cam ring 90 form a pumping volume disposed radially betw een outer radial surface 64 of rotor 60 and opposed inner radial surface 93 of cam ring 90 and axially between lower port plate 70 and upper port plate 80.

[0059] As shown, pump shaft 55 is rotationally coupled to motor shaft 43 at coupling 44 via shaft extension 45 such that pump shaft 55 rotates with rotation of motor shaft 43 about center axis x-x relative to housing 31. Pump shaft 55 includes external splined section 56 having a plurality of circumferentially spaced longitudinally extending external spline teeth 57 and slots 58 therebetween.

[0060] As shown, lower port plate 70 is generally bounded by transverse-extending downwardly- Pacing annular input face 71, longitudinally-extending outw ardly- Pacing cylindrical surface 74, transverse-extending upwardly-facing annular output face 72, and longitudinally- extending inwardly -facing cylindrical surface 73a forming center through-bore 73 through which shaft 55 extends. Port plate 70 includes a first axially extending, circumferentially positioned.arcuate inlet port 75 formed by through-surface 75 a extending between input face 71 and output face 72. Port plate 70 also includes a second axially extending, circumferentially positioned, arcuate inlet port 76 formed by through-surface 76a extending between input face 71 and output face 72. Through ports 75 and 76 of lower port plate 70 are fluid connected to pump inlet 38 via inlet chamber 38c and inlet channel 38a to inlet port 75 and inlet channel 38b to inlet port 76.

[0061] As shown, rotor 60 is generally bounded by transverse-extending downwardly -facing annular input face 61. longitudinally-extending outwardly-facing cylindrical surface 64, transverse-extending upwardly-facing annular output face 62, and longitudinally-extending inwardly-facing cylindrical surface 63a forming center through-bore 63 into which shaft 55 extends. Outer surface 64 of rotor 60 has a plurality of vane slots 65 that extending radially inwardly from surface 64 to inner blind ends 69 and that are circumferentially spaced about axis x-x such that a corresponding plurality of vanes 51 are received in slots 65 and slide radially in respective vane slots 65 of rotor 60. Rotor 60 includes internal splined section 66 having a plurality7of circumferentially spaced longitudinally extending internal spline teeth 67 and slots 68 therebetween in meshed engagement with external splines 57 and slots 58 of external splined section 56 of shaft 55 such that rotor 60 rotates with rotation of pump shaft 55 about axis x-x. Input face 61 of rotor 60 is axially opposed to outlet face 72 of stationary port plate 70 across axial rotary7gap 101 having axial tolerance or clearance width 101a.

[0062] As shown, cam ring 90 is generally bounded by transverse-extending down ardly -facing annular face 91, longitudinally-extending outwardly-facing cylindrical surface 94, transverse- extending upwardly -facing annular face 92, and longitudinally-extending inwardly -facing cam surface 93. Cam ring 90 is connected to housing 31 so that it remains stationary relative to rotor 60. Inner surface 93 of cam ring 90 is eccentric relative to outer surface 64 of rotor 60 so as to form variable rotary radial gap and pumping volume 100 between eccentric surfaces 93 and 64 of stationary cam ring 90 and rotor 60, respectively.

[0063] As shown, upper port plate 80 is generally bounded by7transverse-extending downwardly-facing annular input face 81, longitudinally-extending outwardly-facing cylindrical surface 84. transverse-extending upwardly -facing annular output face 82, and longitudinally- extending inwardly -facing cylindrical surface 83a forming center through-bore 83 through which shaft 55 extends. Port plate 80 includes a first axially extending, circumferentially positioned, arcuate outlet port 85 formed by through-surface 85a extending between input face 81 and output face 82. Port plate 80 also includes a second axially extending, circumferentially positioned, arcuate outlet port 86 formed by through-surface 86a extending between input face 81 and output face 82. Through ports 85 and 86 of upper port plate 80 are fluid connected to pump outlet 39via outlet channel 39a from port 85 and outlet channel 39b from port 86. Outlet ports 85 and 86 of upper port plate 80 are fluid connected to inlet ports 75 and 76 of lower port plate 70 via pumping volume 100 between rotor 60 and cam ring 90. Output face 62 of rotor 60 is axially opposed to inlet face 81 of stationary port plate 80 across axial rotary gap 102 having axial tolerance or clearance width 102a.

[0064] Thus, pumping volume 100 is disposed radially between outer radial surface 64 of rotor 60 and opposed eccentric inner radial surface 93 of cam ring 90 and axially between outlet face 72 of lower port plate 70 and inlet face 81 of upper port plate 80. Vanes 51 in slots 65 of rotor 60 slide radially so that outer ends 54 of vanes 51 maintain contact with inner surface 93 of cam ring 90 as rotor 60 rotates about axis x-x. Vanes 51 have transverse thickness 52 through pumping volume 100 and operatively divide pumping volume 100 into leading pumping chamber 99 on leading axially extending side 99a of vane 51 and trailing pumping chamber 98 on trailing axially extending side 98a of vane 51 and axially between lower port plate 70 and upper port plate 80 to form leading pumping chambers 99 on leading sides 99a of vanes 51 and trailing pumping chambers 98 on trailing sides 98a of vanes 51 as they rotate about axis x-x.

[0065] As shown in FIGS. 10A-15D, each of outlet ports 85 and 86 of upper port plate 80 include specially-configured pressure relief grooves 87 and 88, respectively. With respect to outlet port 85, through-surface 85a of outlet port 85 has leading axially-extending circumferential end 85b and trailing axially-extending circumferential end 85c relative to a clockwise-rotating rotor 60 and vanes 51. Pressure relief groove 87 is a recessed groove in annular input face 81 of upper port plate 80 that extends circumferentially from through-surface 85c proximate to trailing axially -extending circumferential end 85c of port 85 to trailing circumferential pressure relief end 87a of relief groove 87. Thus, fluid in port 85 has a pressure path from open end 87b of groove 87, at its junction with port surface 85a, to closed end 87a of groove 87. As shown in FIG. 15 A, pressure relief groove 87 has circumferential length 89a between open end 87b at through-surface 85a of port 85 and trailing end 87a that is greater than transverse thickness 52 of vanes 51. As shown in FIGS. 15 A- 15D, pressure relief groove 87 provides a pressure connection between leading pumping chamber 99 on leading side 99a of vanes 51 and trailing pumping chamber 98 on trailing side 98a of vanes 51 as vanes 51 rotate clockwise relative to port 85 and relief groove 87 at the trailing end thereof.

[0066] With respect to outlet port 86, through-surface 86a of outlet port 86 has leading axially- extending circumferential end 86b and trailing axially-extending circumferential end 86c relative to a clockwise-rotating rotor 60 and vanes 51. Pressure relief groove 88 is a recessed groove in annular input face 81 of upper port plate 80 that extends circumferentially from through-surface86c proximate to trailing axially-extending circumferential end 86c of port 86 to trailing circumferential pressure relief end 88a of relief groove 88. Thus, fluid in port 86 has a pressure path from open end 88b of groove 88, at its junction with port surface 86a, to closed end 88a of groove 88. Pressure relief groove 88 has circumferential length 89b between open end 88b at through-surface 86a of port 86 and trailing end 88a that is greater than transverse thickness 52 of vanes 51. Pressure relief groove 88 provides a pressure connection between leading pumping chamber 99 on leading side 99a of vanes 51 and trailing pumping chamber 98 on trailing side 98a of vanes 51 as vanes 51 rotate clockwise relative to port 86 and relief groove 88 at the trailing end thereof.

[0067] As shown, through ports 75 and 76 of lower port plate 70 are orientated 180 degrees from each other about center axis x-x. Likewise, through ports 85 and 86 of upper port plate 80 are orientated 180 degrees from each other about center axis x-x. With this mirrored dual-port orientation, operative loads about center axis x-x of shaft 55 cancel, which reduces side-loading on shaft 55. In addition, lower plate 70 includes surface groove 185 with secondary7groove surface 187 in outlet face 72 of lower plate 70. Grooves 185 and 187 are not through-ports and do not extend through plate 70 to inlet face 71, but their outer contour and circumferential location mirrors the outer contour and circumferential location about axis x-x of outlet port 85 and relief groove 87 in inlet face 81 of upper port plate 80, respectively. Lower plate 70 also includes surface groove 186 with secondary groove surface 188 in outlet face 72 of lower plate 70. Grooves 186 and 188 are also not through-ports and do not extend through plate 70 to inlet face 71, but their outer contour and circumferential location mirrors the outer contour and circumferential location about axis x-x of outlet port 86 and relief groove 88 in inlet face 81 of upper port plate 80, respectively. Upper plate 80 includes surface groove 175 in inlet face 81 of upper plate 80. Groove 175 is not a through-port and does not extend through plate 80 to outlet face 82, but its outer contour and circumferential location mirrors the outer contour and circumferential location about axis x-x of inlet port 75 in outlet face 72 of lower port plate 70. Upper plate 80 also includes surface groove 176 in inlet face 81 of upper plate 80. Groove 176 is also not a through-port and does not extend through plate 80 to outlet face 82, but its outer contour and circumferential location mirrors the outer contour and circumferential location about axis x-x of inlet port 76 in outlet face 72 of lower port plate 70.

[0068] As shown in FIGS. 9A-11B, a pressurized fluid system is configured to operatively provide pressurized fluid to specially configured fluid bearing and undervane channels between port plates 70 and 80 and rotor 60, and vanes 51 and rotor 60, respectively. In particular, through- holes 110 and 11 1 extend longitudinally through upper port plate 80 and provide a fluidconnection between the higher pressure outflow of outlet ports 85 and 86 on outlet side 82 of upper plate 80 to inlet side 81 of upper plate 80. Through-holes 110 and 111 are orientated 180 degrees from each other about center axis x-x. Inlet face 81 of upper plate 80 includes annular distribution groove 112 and through holes 110 and 111 are radially aligned with and empty into distribution groove 112 on inlet side 81 of upper plate 80. Each of blind ends 69 of vane slots 65 of rotor 60 include axially extending undervane pressure groove 115 radially facing inner end 53 of vanes 51 in slots 65, respectively. Annular distribution groove 112 in inlet face 81 of upper port plate 80 is radially aligned with the open topside ends of longitudinally extending undervane pressure grooves 115 in blinds ends 69 of slots 65 of rotor 60 and provide a fluid connection from through holes 110 and 111 at the inlet side 81 of upper plate 80 to pressure grooves 115 of rotor 60 at the topside face 62 of rotor 60. Outlet face 72 of lower plate 70 includes annular distribution groove 116 and annular distribution groove 116 in outlet face 72 of lower port plate 70 is radially aligned with the open downside ends of longitudinally extending undervane pressure grooves 115 in blinds ends 69 of slots 65 of rotor 60. Undervane pressure grooves 115 in blinds ends 69 of slots 65 of rotor 60 provide an axial-extending fluid connection between annular distribution groove 112 in the inlet side 81 of upper plate 80 and annular distribution groove 116 in the outlet side 72 of lower plate 70. Pressurized fluid in undervane pressure grooves 115 also provide a radial pressure to the inner radial ends 53 of vanes 51 to bias vanes 51 to maintain contact with inner cam surface 93 of cam ring 90 at outer ends 54 of vanes 51 as pump shaft 55 rotates about axis x-x.

[0069] Inlet face 81 of upper plate 80 also includes arcuate fluid bearing grooves 113 and 114 in fluid communication with annular distribution groove 112 of port plate 80. Bearing groove 113 has an open inlet in fluid communication with annular distribution groove 112 at circumferential junction 113a on the inside radius of annular distribution groove 112. Bearing groove 113 extends circumferentially almost 180 degree about axis x-x to closed terminus 113b and is positioned radially opposite annular output end face 62 of rotor 60 and radially inwards from distribution groove 112 and the upper open ends of undervane grooves 115 and blind ends 69 of vane slots 65 of rotor 60. Bearing groove 114 has an open inlet in fluid communication with annular distribution groove 112 at circumferential junction 114a on the inside radius of annular distribution groove 1 12. Bearing groove 114 extends circumferentially almost 180 degree about axis x-x to closed terminus 114b and is also positioned radially opposite annular output end face 62 of rotor 60 and radially inwards from distribution groove 112 and the upper open ends of undervane grooves 115 and blind ends 69 of vane slots 65 of rotor 60. In this embodiment, junctions 1 13a and 114a between bearing grooves 113 and 114 and distribution groove 112 areorientated 180 degrees from each other about center axis x-x. In this embodiment, closed terminuses 113b and 114b of bearing grooves 113 and 114 are also orientated 180 degrees from each other about center axis x-x. Pressurized fluid in bearing grooves 113 and 114 provides a fluid bearing at rotary gap 102 between opposed annular faces 81 and 62 of upper port plate 80 and pump rotor 60, respectively.

[0070] Outlet face 72 of lower plate 70 also includes arcuate fluid bearing grooves 117 and 118 in fluid communication with annular distribution groove 116 of port plate 70. Bearing groove 1 17 has an open inlet in fluid communication with annular distribution groove 1 16 at circumferential junction 117a on the inside radius of annular distribution groove 116. Bearing groove 117 extends circumferentially almost 180 degree about axis x-x to closed terminus 117b and is positioned radially opposite annular input end face 61 of rotor 60 and radially inwards from distribution groove 1 16 and the lower open ends of undervane grooves 115 and blind ends 69 of vane slots 65 of rotor 60. Bearing groove 118 has an open inlet in fluid communication with annular distribution groove 116 at circumferential junction 118a on the inside radius of annular distribution groove 116. Bearing groove 118 extends circumferentially almost 180 degree about axis x-x to closed terminus 118b and is also positioned radially opposite annular input end face 61 of rotor 60 and radially inwards from distribution groove 1 16 and the lower open ends of undervane grooves 115 and blind ends 69 of vane slots 65 of rotor 60. In this embodimentjunctions 117a and 118a between bearing grooves 117 and 118 and distribution groove 116 are orientated 180 degrees from each other about center axis x-x. In this embodiment, closed terminuses 117b and 118b of bearing grooves 1 17 and 118 are also orientated 180 degrees from each other about center axis x-x. Pressurized fluid in bearing grooves 117 and 118 provides afluid bearing at rotary gap 101 between opposed annular faces 72 and 61 of lower port plate 70 and pump rotor 60, respectively.

[0071] In this embodiment, lower port plate 70, upper port plate 80, pump rotor 60, cam ring 90, and vanes 51 each have a Rockwell C scale hardness of greater than 70 HRc. In a representative example embodiment, lower port plate 70, upper port plate 80, pump rotor 60, cam ring 90, and vanes 51 are formed of tungsten carbide and in a representative example embodiment comprise a sintered tungsten carbide powder. For example, in a representative example embodiment, tungsten carbide powder, titanium carbide powder, chromium carbide powder, nickel and cobalt are mixed together and dried. The mixed and dried powder is then placed in a die of the respective lower port plate 70, upper port plate 80, pump rotor 60, cam ring 90, or vane 51 and pressed into shape. The parts may be pressed using axial or isostatic pressing. The parts are then sintered in an anaerobic thermal process that heats the powder to just below its melting point andfuses the metal. Other metal or hybrid powders may be used as alternatives. For example, and without limitation, the metal or hybrid powder may be selected from a group consisting of tungsten carbide, silicon carbide, chromium carbide, silicon nitride, boron nitride, aluminum oxide, and a cobalt-based chromium and tungsten alloy. Thus, in this embodiment the lower port plate 70, upper port plate 80, pump rotor 60, cam ring 90, and vanes 51 are generally formed by heating compacted metal or hybrid powders to j ust below their melting points using a press-and- sinter powder metallurgy process. In another representative example embodiment, low er port plate 70, upper port plate 80, pump rotor 60, cam ring 90, and vanes 51 are formed of a ceramic and in a representative example embodiment comprise an alumina or aluminum oxide ceramic or a zirconia or zirconium dioxide ceramic.

[0072] As shown in FIGS. 7-8C, inwardly -facing middle section 66 of rotor 60 includes longitudinally extending internal spline teeth 67 and slots 68 that interface with similarly extending external splines 57 and slots 58 on the outside surface of section 56 of shaft 55. As shown, spline section 56 of shaft 55 comprises an external shaft spline having a plurality of axially extending external shaft spline teeth 57, with each of shaft spline teeth 57 having circular shaft spline tooth thickness 57a. Spline section 66 of rotor 60 in turn comprises an internal rotor spline in engagement with the external shaft spline and having a plurality of axially extending internal rotor spline slots 68 that receive teeth 57 of shaft 55, with each rotor spline slot 68 having circular internal spline space width 68a. Splines 57 and 67 and slots 58 and 68 are specially configured to provide maximum rotor-to-shaft outer axial offset tolerance 130 that is greater than the sum of axial gap widths 101a and 102a between rotor 60 and port plates 70 and 80, respectively. Thus, in this embodiment, splines 57 and 67 and slots 58 and 68 of shaft 55 and rotor 60, respectively, are sized and configured such that the splined interface between rotor 60 and shaft 55 has enough play or permitted outer axial offset tolerance 130 to account for cumulative port plate 70 and 80 misalignments to rotor 60. In particular, in this embodiment, splines 57 and 67 and slots 58 and 68 of shaft 55 and rotor 60, respectively, are sized and configured to provide a maximum outer axial offset tolerance 130 (de) that is greater than the sum of axial gap width 101a between parallel faces 61 and 72 of rotor 60 and lower port plate 70 and axial gap width 102a between parallel faces 62 and 81 of rotor 60 and upper port plate 80 (de > (101a + 102a)). Radial offset angle 131 ( .bac) between the rotational center lines of shaft 55 and rotor 60 may be varied between a maximum tolerance angle limit when circular space width 68a is a maximum and circular tooth thickness 57a is a minimum and a minimum tolerance angle limit when circular space width 68a is a minimum and circular tooth thickness57a is a maximum. In particular, in this embodiment, de = fe X sin( bac), where fe = — and Abac = sin-1^. Length ab is half axial width 56a of spine section 56 of shaft 55 (ab = ^). Radial offset distance 131 (be) at the axial edge of splined section 56 of shaft 55 is a function of circular space width 68a of slot 68 of internal spline section 66 of rotor 60, circular tooth thickness 57a of tooth 57 of external spline section 56 of shaft 55, and pressure angle 121, where pressure angle 121 is the angle between line 121a, which is normal to a tangent line to the contact surface of spline teeth 57 at circular pitch diameter 120 of spline sections 56 and 66 of shaft 55 and rotor 60, and line 121b, which is a tangent line to circular pitch diameter 120 at the contact surface of spline teeth 57 of spline section 56 of shaft 55 (be ='ri arepresentative embodiment, maximum rotor-to-shaft outer axial offset tolerance 130 may be at least ten percent greater than the sum of axial rotor entry' clearance width 101a and axial rotor exit clearance width 102a. In a representative embodiment, spline section 56 of shaft 55 may comprise at least ten circumferentially spaced teeth 57 separated by at least ten slots 58, and in the shown embodiment comprises twenty-four alternating teeth 57 and slots 58, and spline section 66 of rotor 60 may comprise at least ten circumferentially spaced teeth 67 separated by at least ten slots 68, and in the shown embodiment comprises tw enty-four alternating teeth 67 and slots 68.

[0073] Thus, pump unit 30 has inlet 38 of lower manifold section 34 and outlet 39 of upper manifold section 32 and fluid passages 38a, 38b, 38c, 100, 39a, and 39b therebetween. When vanes 51 attached to pump rotor 60 are rotationally driven by motor 40, such rotary motion of vanes 51 carries production fluid from inlet 38 of unit 30 and inlet ports 75 and 76 of pump 50 to outlet ports 85 and 86 of pump 50 and outlet 39 of unit 30. In operation, production fluid is directed to flow in through inlet 38 of manifold section 34 and, via fluid passages 38a, 38b, 38c, through suction ports 75 and 76 of pump 50 to pumping chamber 100, and then through discharge ports 85 and 86 of pump 50 and, via fluid passages 39a, 39b, out through outlet 39 of upper manifold section 32.

[0074] Referring now to FIGS. 16-19, a multiple stage vane pump example embodiment of a pump unit is general indicated at 230. Pump unit 230 generally comprises multiple stage vane pump 250 driven by electric motor 40, all of which are contained in cylindrical housing 231. Cylindrical housing 231 generally comprises top manifold outlet section 32 connected to the downhole end of tubing string 17, pump housing section 233 containing multiple stage vane pump 250 and positioned below top manifold outlet 32, pump-to-motor adapter housing section34 positioned below pump housing section 233, motor housing section 35 positioned below adapter section 34 and containing motor 40, and bottom motor end cap 36. Pump housing 231 includes pump inlet 38 in adapter section 34 for receiving production or well fluids, and pump outlet 39 in top manifold block 32 for outputting well fluids at a higher pressure than pump inlet 38. Adaptor section 34, motor housing 34, motor end cap 36 and motor 40 with output shaft 43 and extension 45 are generally as shown and described above with reference to single stage embodiment 30. Pump unit 230 forces a volume of fluid upward within production tubing 17.

[0075] In this embodiment, vane pump 250 has two stages 250a and 250b. The speed and output of each of stages 250a and 250b is variable with variations in the speed of motor 40. Common pump shaft 255 is rotationally coupled via extension shaft 45 to solid output shaft 43 of electric motor 40 such that pump shaft 255 rotates with rotation of motor shaft 43 about center axis x-x relative to housing 231. Pump shaft 255 includes lower external splined section 56 having a plurality of circumferentially spaced longitudinally extending external splines 57 and upper external splined section 256 also having a plurality of circumferentially spaced longitudinally extending external splines 57.

[0076] First stage 250a is generally as shown and described above with reference to vane pump 50 of single stage embodiment 30, including with respect to material composition, spline configuration, pressure relief, and internal fluid bearing and distribution configurations. Accordingly, stage 250a generally comprises lower port plate 70 supported by housing section 233, upper port plate 80 supported by housing section 233, cam ring 90 supported by housing section 233 and disposed axially between lower port plate 70 and upper port plate 80, pump rotor 60 rotationally coupled to pump shaft 255 via lower splined section 56 and disposed axially between lower port plate 70 and upper port plate 80 and having a plurality of circumferentially spaced and axially extending vane slots 65, and a plurality of vanes 51 disposed axially between lower port plate 70 and upper port plate 80 and slidingly supported in the respective vane slots 65 of rotor 60 and operatively configured to extend radially between outer radial surface 64 of rotor 60 and opposed inner radial surface 93 of cam ring 90. Radially extending vanes 51 rotate in cam ring 90 when shaft 255 and rotor 60 are driven by connected motor 40. Vanes 51 may have variable lengths and are biased to maintain contact with ring 90 as pump shaft 255 rotates. Rotor 60 with circumferentially spaced vanes 51 radially bearing against cam ring 90 form a first pumping volume disposed radially between outer radial surface 64 of rotor 60 and opposed inner radial surface 93 of cam ring 90 and axially between lower port plate 70 and upper port plate 80.

[0077] Second stage 250b is stacked above first stage 250a and is generally configured as shown and described above with reference to vane pump 50 of single stage embodiment 30, includingwith respect to material composition, spline configuration, pressure relief, and internal fluid bearing and distribution configurations. Second stage 250b generally comprises lower port plate 270 supported by housing section 233, upper port plate 280 supported by housing section 233, cam ring 290 supported by housing section 233 and disposed axially between lower port plate 270 and upper port plate 280, pump rotor 260 rotationally coupled to pump shaft 255 via upper splined section 256 and disposed axially between lower port plate 270 and upper port plate 280 and having a plurality of circumferentially spaced and axially extending vane slots 265, and a plurality of vanes 251 disposed axially between lower port plate 270 and upper port plate 280 and slidingly supported in the respective vane slots 265 of rotor 260 and operatively configured to extend radially between outer radial surface 264 of rotor 260 and opposed inner radial surface 293 of cam ring 290. Radially extending vanes 251 rotate in cam ring 290 when shaft 255 and rotor 260 are driven by connected motor 40. Vanes 251 may have variable lengths and are biased to maintain contact with ring 290 as pump shaft 255 rotates. Rotor 260 with circumferentially spaced vanes 251 radially bearing against cam ring 290 form a second pumping volume disposed radially between outer radial surface 264 of rotor 260 and opposed inner radial surface 293 of cam ring 290 and axially between lower port plate 270 and upper port plate 280.

[0078] Regarding first stage pump 250a, lower port plate 70 is generally configured as shown and described above with reference to port plate 70 of single stage embodiment 30, including having inlet ports 75 and 76 and with respect to material composition, pressure relief, and internal fluid bearing and distribution configurations. Through ports 75 and 76 of lower port plate 70 are fluid connected to pump inlet 38 via inlet chamber 38c and inlet channel 38a to inlet port 75 and inlet channel 38b to inlet port 76. Rotor 60 is generally configured as shown and described above with reference to rotor 60 of single stage embodiment 30, including with respect to material composition, spline configuration, and internal fluid bearing and distribution configurations, and includes internal splined section 66 having a plurality of circumferentially spaced longitudinally extending internal splines 67 in meshed engagement with external splines 57 of external splined section 56 of shaft 255 such that rotor 60 rotates with rotation of pump shaft 255 about axis x-x. Input face 61 of rotor 60 is axially opposed to outlet face 72 of stationary port plate 70 across axial rotary gap 101. Cam ring 90 is generally configured as shown and described above with reference to port plate cam ring 90 of single stage embodiment 30, including with respect to material composition, and is connected to housing 231 so that it remains stationary relative to rotor 60. Inner surface 93 of cam ring 90 is eccentric relative to outer surface 64 of rotor 60 so as to form variable rotary radial gap and first pumping volume 100 between eccentric surfaces 93 and 64 of stationary cam ring 90 and rotor 60, respectively. Upper port plate 80 is generallyconfigured as shown and described above with reference to port plate 80 of single stage embodiment 30. including having outlet ports 85 and 86 and with respect to material composition, pressure relief, and internal fluid bearing and distribution configurations. Outlet ports 85 and 86 of upper port plate 80 are fluid connected to inlet ports 75 and 76 of lower port plate 70 via first pumping volume 100 between rotor 60 and cam ring 90. Output face 62 of rotor 60 is axially opposed to inlet face 81 of stationary port plate 80 across axial rotary gap 102.

[0079] Regarding second stage pump 250b. lower port plate 270 is also generally configured as shown and described above with reference to port plate 70 of single stage embodiment 30, including having inlet ports 275 and 276 and with respect to material composition, pressure relief, and internal fluid bearing and distribution configurations. Through port 275 of lower port plate 270 of second stage pump 250b is fluid connected to outlet port 85 of upper port plate 80 of first stage pump 250a via connecting channel 139a. Through port 276 of lower port plate 270 of second stage pump 250b is fluid connected to outlet port 86 of upper port plate 80 of first stage pump 250a via connecting channel 139b. Rotor 260 is generally configured as shown and described above with reference to rotor 60 of single stage embodiment 30. including with respect to material composition, spline configuration, and internal fluid bearing and distribution configurations, and includes internal splined section 266 having a plurality of circumferentially spaced longitudinally extending internal splines 67 in meshed engagement with external splines 57 of external splined section 256 of shaft 255 such that rotor 260 rotates with rotation of pump shaft 255 about axis x-x. Input face 261 of rotor 260 is axially opposed to outlet face 272 of stationary port plate 270 across axial rotary gap 201. Cam ring 290 is generally configured as show n and described above with reference to port plate cam ring 90 of single stage embodiment 30, including with respect to material composition, and is connected to housing 231 so that it remains stationary relative to rotor 260. Inner surface 293 of cam ring 290 is eccentric relative to outer surface 264 of rotor 260 so as to form a variable rotary radial gap and second pumping volume 200 between eccentric surfaces 293 and 264 of stationary cam ring 290 and rotor 260, respectively. Upper port plate 280 is generally configured as shown and described above with reference to port plate 80 of single stage embodiment 30, including having outlet ports 285 and 286 and with respect to material composition, pressure relief, and internal fluid bearing and distribution configurations. Outlet ports 285 and 286 of upper port plate 280 are fluid connected to inlet ports 275 and 276 of low er port plate 270 via second pumping volume 200 between rotor 260 and cam ring 290. Output face 262 of rotor 260 is axially opposed to inlet face 281 of stationary port plate 280 across axial rotary gap 202. Through ports 285 and 286 of upper portplate 280 are fluid connected to pump outlet 39 via outlet channel 239a from port 285 and outlet channel 239b from port 286.

[0080] Thus, pump unit 230 has inlet 38 of lower manifold section 34 and outlet 39 of upper manifold section 32 and fluid passages 38a, 38b, 38c, 100, 139a, 139b, 200, 239a, and 239b therebetween. When vanes 51 of pump rotor 60 and vanes 251 of pump rotor 260 are rotationally driven by motor 40, such rotary motion of vanes 51 and 251 carries production fluid from inlet 38 of unit 30 and inlet ports 75 and 76 of pump stage 250a to outlet ports 285 and 286 of pump stage 250b and outlet 39 of unit 230. In operation, production fluid is directed to flow in through inlet 38 of manifold section 34 and, via fluid passages 38a, 38b, 38c, in through suction ports 75 and 76 of first pump stage 250a to pumping chamber 100, and then out through discharge ports 85 and 86 of first pump stage 250a. and then, via fluid passages 139a and 139b, in through suction ports 275 and 276 of second pump stage 250b to pumping chamber 200, and then out through discharge ports 285 and 286 of second pump stage 250b, and then, via fluid passages 239a and 239b, out through outlet 39 of upper manifold section 32. Thus, pump unit 230 includes pump inlets 38 in manifold block 34 for receiving production or well fluids, and pump outlet 39 in manifold block 32 for outputting well fluids at a higher pressure than pump inlet 38. Accordingly, pump unit 230 forces a volume of fluid upward within production tubing 17 with pump stages 250a and 250B arranged to provide series flow at the desired level of lift.

[0081] Referring now to FIGS. 20-22. an alternative embodiment of a vane is general indicated at 151. Similar to vane 51, vane 151 generally comprises leading surface 199a, trailing surface 198a, and inner end portion 153 having rounded inner surface 153 generated about radius 153r between leading side surface 199a and trailing side surface 198a. However, in this embodiment outer end portion 154 comprises angled end surface 154c between leading side surface 199a and trailing side surface 198a. Outer leading edge 154a is formed at the axially-extending junction between leading side surface 199a and angled end surface 154c and trailing edge 154b is formed at the axially-extending junction between trailing side surface 198a and angled end surface 154c, with trailing edge 154b offset radially inward to leading edge 154a by offset distance 154e. As shown, in this embodiment axially extending angled end surface 154c is orientated at internal offset angle 154d relative to leading side surface 199a of vane 151. Offset angle 154d is less than ninety degrees. In this embodiment, offset angle 154d is less than eighty-five degrees, is preferably less than seventy-five degrees, and may be about seventy degrees. In this embodiment leading edge 154a is generated about minimal radius 154r between leading side surface 199a and outer surface 154c. In this embodiment, radius 154r is less than about 0.3 mm and preferably is about 0.2 mm.

[0082] Vanes 151 are disposed in slots 65 of rotor 60 so as to slide radially such that leading edge 154a of outer canted end 154 of vanes 151 maintain contact with inner surface 93 of cam ring 90 as rotor 60 rotates about axis x-x and such that trailing edge 154b of vanes 151 are recessed from contact with inner surface 93 of cam ring 90 by relief offset gap 154e. Vanes 151 have transverse thickness 152 through pumping volume 100 and operatively divide pumping volume 100 into leading pumping chamber 99 on leading axially extending side 199a of vane 151 and trailing pumping chamber 98 on trailing axially extending side 198a of vane 151 and axially between lower port plate 70 and upper port plate 80 to form leading pumping chambers 99 on leading sides 199a of vanes 151 and trailing pumping chambers 98 on trailing sides 198a of vanes 51 as they rotate about axis x-x. With this configuration, including with small radius 154r forming sharp leading contact edge 154a and trailing offset edge 154b being radially recessed relative to leading edge 154a on inner surface 93 of cam ring 90 as rotor 60 rotates about axis x-x, leading edge 154a operates as an excluder to scrape away particles that could otherwise become wedged between vane tip 154 and cam ring 90, and inwardly sloped surface 154c operates as a relief to allow evacuation of particles that get past leading edge 154a and could otherwise become wedged between vane tip 154 and cam ring 90, resulting in decreased wear.

[0083] Different combinations and numbers of pumping stages may be interchangeably employed as desired. Thus, more than two vane pump stages may be stacked and connected in series in the pump housing and driven by a common motor and shaft. Different combinations and numbers of pumping stages may be interchangeably employed as desired.

[0084] Pump systems 15 has a number of advantages. The system provides pumping capabilities in a housing that fits in the constrained operating envelope of a well or subsea installation, such as a four inch diameter envelope. The system provides higher reliability and greater operational longevity. The system is easily scalable and customizable. The system is customizable in the type of motor to be used and is scalable in size by adding pumping stages to the stack as needed. The system reduces rotor to port plate uneven and misalignment wear and galling. The system reduces cam ring wear. The system reduces internal pump side loading. The system provides increased pressure balance. The system provides pressure relief on the discharge ports and the suction ports. The system provides improved oil retention and pressurized oil use. The system reduces the pressure load on each pump segment allowing operation in the harsh environment of shale oil pumping for example.

[0085] It should be appreciated that certain features of the system, which are, for clarity', described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features, which are, for brevity, described in the contextof a single embodiment, may also be provided separately or in any suitable combination. While various embodiments have been described in detail above, it should be understood that they have been presented by way of example, and not limitation. It will be apparent to persons skilled in the relevant arts that the disclosed subject matter may be embodied in other specific forms, variations, and modifications without departing from the scope, spirit, or essential characteristics thereof. The embodiments described above are therefore to be considered in all respects as illustrative, and not restrictive.

[0086] While alternative forms of the improved subsurface pump system have been shown and described, and several modifications thereof discussed, persons skilled in this art will readily appreciate that various additional changes and modifications may be made without departing from the scope of the invention, as defined, and differentiated by the claims.

Claims

CLAIMSWhat is claimed is:

1. A well installation, comprising: tubing arranged in a well and forming a flow channel to a surface level for fluids originating from below said surface level; a motor pump housing disposed in said well; a motor disposed in said housing and comprising a motor shaft configured to rotate about a motor axis; a pump inlet and a pump outlet in said housing; a vane pump disposed in said housing between said pump inlet and said pump outlet; said vane pump comprising: an entry' port plate supported by said housing and having an inlet port connected to said pump inlet; an exit port plate supported by said housing and having an outlet port connected to said pump outlet; a cam ring supported by said housing and disposed axially between said entry7port plate and said exit port plate; a pump shaft orientated about a shaft axis and rotationally coupled to said motor shaft; a rotor rotationally coupled to the pump shaft and disposed axially between said entry7port plate and said exit port plate; said rotor and said cam ring forming a pumping volume disposed radially between an outer radial surface of said rotor and an opposed inner radial surface of said cam ring and axially between said entry port plate and said exit port plate; said rotor comprising a plurality of circumferentially spaced vane slots; and a plurality' of axially-extending vanes slidingly supported in said respective vane slots of said rotor and operatively configured to extend radially between said outer radial surface of said rotor and said opposed inner radial surface of said cam ring; wherein said motor is operatively driven to pump a production fluid from said inlet to said outlet through said vane pump.

2. The well installation set forth in claim 1. wherein: said vane pump comprises a first stage and a second stage;said first stage comprises said rotor rotationally coupled to said pump shaft and having said plurality of circumferentially spaced vane slots, said cam ring supported by said housing, said plurality of vanes slidingly supported in said respective vane slots of said rotor, said entry port plate supported by said housing and having an inlet port connected to said pump inlet, and said exit port plate supported by said housing and having an outlet port; said second stage comprises a second rotor rotationally coupled to said pump shaft and having a second plurality of circumferentially spaced vane slots, a second cam ring supported by said housing, a second plurality of vanes slidingly supported in said respective vane slots of said second rotor, a second entry' port plate supported by said housing and having an inlet port connected to said outlet port of said exit port plate of said first stage, and a second exit port plate supported by said housing and having a second outlet port connected to said pump outlet; said second stage is operatively configured in series with said first stage; and wherein said motor is operatively driven to pump said production fluid from said inlet to said outlet in series through said first stage and said second stage3. The well installation set forth in claim 1 or 2, wherein said entry' port plate, said exit port plate, said rotor, said cam ring, and said vanes each have a Rockwell C scale hardness greater than 70 HRc.

4. The well installation set forth in claim 3. wherein said entry port plate, said exit port plate, said rotor, said cam ring, and said vanes each comprises tungsten carbide.

5. The well installation set forth in claim 3. wherein said entry port plate, said exit port plate, said rotor, said cam ring, and said vanes each comprise at least one of a sintered metal, a hybrid powder, and a ceramic.

6. The well installation set forth in claim 5. wherein said sintered metal, hybrid powder or ceramic is selected from a group consisting of tungsten carbide, silicon carbide, chromium carbide, silicon nitride, boron nitride, aluminum oxide, a cobalt-based chromium and tungsten alloy, alumina ceramic, and zirconia ceramic.

7. The well installation set forth in claim 1 or 2, wherein: said entry7port plate comprises an annular output face orientated perpendicular to said shaft axis; said rotor comprises an annular input end face axially opposed to said annular output face of said entry port plate;said entry port plate and said rotor comprise an axial rotor entry clearance between said annular output face of said entry port plate and said annular input end face of said rotor; said exit port plate comprises an annular input face orientated perpendicular to said shaft axis; said rotor comprises an annular output end face axially opposed to said annular input face of said exit port plate; said rotor and said exit port plate comprise an axial rotor exit clearance between said annular output end face of said rotor and said annular input face of said exit port plate; said shaft comprises an external shaft spline having a plurality of axially extending external shaft spline teeth, each of said shaft spline teeth comprising a circular shaft spline tooth thickness; said rotor comprises an internal rotor spline in engagement with said external shaft spline and having plurality of axially extending internal rotor spline slots, each of said rotor spline slots comprising a circular internal spline space width; and said circular internal spline space width of said internal rotor spline slots is greater than said circular shaft spline tooth thickness of said shaft spline teeth to provide a maximum rotor- to-shaft outer axial offset tolerance; and a sum of said axial rotor entry clearance and said axial rotor exit clearance is less than said maximum rotor-to-shaft outer axial offset tolerance.

8. The well installation set forth in claim 7, wherein said maximum rotor-to-shaft outer axial offset tolerance is at least ten percent greater than said sum of said axial rotor entry7clearance and said axial rotor exit clearance.

9. The well installation set forth in claim 1 or 2, wherein: said inlet port of said entry7port plate comprises an axially extending, circumferentially positioned, arcuate first inlet port connected to said pump inlet; and said inlet port of said entry port plate comprises an axially extending, circumferentially positioned, arcuate second inlet port connected to said pump inlet.

10. The well installation set forth in claim 9, wherein: said outlet port of said exit port plate comprises an axially extending, circumferentially positioned, arcuate first outlet port connected to said pump outlet; and said outlet port of said exit port plate comprises an axially extending, circumferentially positioned, arcuate second outlet port connected to said pump outlet.

11. The well installation set forth in claim 10, wherein: said first inlet port is circumferentially spaced apart from said second inlet port by about 180 degrees; and said first outlet port is circumferentially spaced apart from said second outlet port by about 1 0 degrees.

12. The well installation set forth in claim 1 or 2, wherein: said vanes have a maximum transverse thickness through said pumping volume and are operatively configured to divide said pumping volume into a leading pumping chamber on a leading axially extending side of said vanes and a trailing pumping chamber on a trailing axially extending side of said vanes between said entry port plate and said exit port plate; said exit port plate comprises an annular input face orientated perpendicular to said shaft axis and an annular output face orientated perpendicular to said shaft axis; said outlet port of said exit port plate comprises an axially-extending, circumferentially positioned, arcuate first outlet port in fluid communication with said pumping volume and formed by a through-surface extending between said annular input face and said annular output face; said through-surface has a leading axially-extending circumferential end and a trailing axially -extending circumferential end; said exit port plate comprises a pressure relief groove in said annular input face extending circumferentially from said through-surface proximate to said trailing axially- extending circumferential end to a trailing circumferential pressure relief end; and said pressure relief groove has a circumferential length between said through-surface and said trailing circumferential pressure relief end that is greater than said maximum transverse thickness of said vanes; whereby said pressure relief groove provides a pressure connection between said leading pumping chamber on said leading axially extending side of said vanes and said trailing pumping chamber on said trailing axially extending side of said vanes.

13. The well installation set forth in claim 12, wherein: said outlet port of said exit port plate comprises an axially-extending, circumferentially positioned, arcuate second outlet port in fluid communication with said pumping volume and formed by a second through-surface extending between said annular input face and said annular output face;said second through-surface has a second leading axially-extending circumferential end and a second trailing axially-extending circumferential end; said exit port plate comprises a second pressure relief groove in said annular input face extending circumferentially from said second through-surface proximate to said second trailing axially-extending circumferential end to a second trailing circumferential pressure relief end; and said second pressure relief groove has a second circumferential length between said second through-surface and said second trailing circumferential pressure relief end that is greater than said maximum transverse thickness of said vanes; whereby said second pressure relief groove provides a second direct pressure connection between said leading pumping chamber on said leading axially extending side of said vanes and said trailing pumping chamber on said trailing axially extending side of said vanes.

14. The well installation set forth in claim 1 or 2, wherein: said exit port plate comprises an annular input face orientated perpendicular to said shaft axis; said outlet port of said exit port plate comprises a first outlet port; said rotor comprises an annular output end face axially opposed to said annular input face of said exit port plate; each of said vane slots of said rotor comprise a blind end; said exit port plate comprises an arcuate fluid bearing groove in said annular input face; said arcuate fluid bearing groove is positioned radially opposite said annular output end face of said rotor and radially inwards from said blind ends of said vane slots of said rotor; and a fluid channel extends between said annular fluid bearing groove and said first outlet port.

15. The well installation set forth in claim 14, wherein: said exit port plate comprises an annular output face orientated perpendicular to said shaft axis; said fluid channel comprises an annular distribution groove in said input face of said exit port plate; and said fluid channel comprises a through-hole in said exit port plate extending between said annular output face and said annular distribution groove.

16. The well installation set forth in claim 15, wherein said arcuate fluid bearing groove comprises a first arcuate bearing groove portion having a first groove inlet in fluid communication with said annular distribution groove at a first circumferential junction and a second arcuate bearing groove portion having a second groove inlet in fluid communication with said annular distribution groove at a second circumferential junction.

17. The well installation set forth in claim 16. wherein said first groove inlet is circumferentially spaced apart from said second groove inlet by about 180 degrees.

18. The well installation set forth in claim 1 or 2, wherein: said exit port plate comprises an annular input face orientated perpendicular to said shaft axis; said outlet port of said exit port plate comprises a first outlet port; said rotor comprises an annular output end face axially opposed to said annular input face of said exit port plate; each of said vane slots of said rotor comprises a blind end having an axially extending undervane pressure groove facing a rotor end of said respective vanes; said input face of said exit port plate comprises an annular distribution groove in fluid communication with said undervane pressure grooves of said vane slots of said rotor; and a fluid channel extends between said annular distribution groove and said first outlet port.

19. The well installation set forth in claim 18, wherein said annular distribution groove is radially aligned with said undervane pressure grooves.

20. The well installation set forth in claim 19, wherein said exit port plate comprises an annular output face orientated perpendicular to said shaft axis and said fluid channel comprises a through-hole in said exit port plate extending between said annular output face and said annular distribution groove.

21. The well installation set forth in claim 1 or 2, wherein: each of said plurality of vanes is operatively configured to divide said pumping volume into a leading pumping chamber on an axially extending leading side of said vanes and a trailing pumping chamber on an axially extending trailing side of said vanes between said entry port plate and said exit port plate; each of said vanes comprises an inner end portion and an outer end portion:said inner end portion of said vane faces a blind end of one of said vane slots of said rotor: said outer end portion of said vane faces said inner radial surface of said cam ring; said outer end portion of said vane comprises an axially extending leading edge on said leading side of said vane and an axially extending trailing edge on said trailing side of said vane: and said trailing edge of said outer end portion of said vane is offset radially inwards relative to said leading edge of said outer end portion of said vane.

22. The well installation set forth in claim 21, wherein said outer end portion comprises an axially extending angled end surface between said leading edge and said trailing edge and said angled end surface is orientated at an internal offset angle relative to said leading side of said vane of less than 85 degrees.

23. The well installation set forth in claim 22, wherein said offset angle is less than 75 degrees.

24. The well installation set forth in claim 22, wherein said leading edge is orientated on a radius between said leading side of said vane and said angled end surface of said vane.

25. The well installation set forth in claim 21, wherein said inner portion of said vane comprises an axially extending rounded end surface between said leading side and said trailing side and said rounded end surface is orientated on a radius between said leading side and said trailing side.

26. The well installation set forth in claim 1 or 2, wherein said motor comprising a stator and a motor rotor rotationally coupled to said motor shaft and configured and arranged to rotate relative to said stator under the effect of a magnetic field generated by said stator.

27. The well installation set forth in claim 26, comprising a cable supplying electric power from said surface level to said stator.

28. The well installation set forth in claim 26, wherein said motor pump housing comprises an actuator housing section defining a first chamber substantially isolated from said well and said stator and said motor rotor are disposed in said first chamber.

29. The well installation set forth in claim 28, wherein said motor pump housing comprises a pump housing section connected to said actuator housing section and said pump shaft is connected to a portion of said motor shaft sealingly penetrating an end portion of said actuator housing section for rotational movement therewith.

30. The well installation set forth in claim 1 or 2, wherein said motor pump housing comprises a pump housing section and said pump is disposed in said pump housing section and said motor pump housing comprises an actuator housing section and said motor is disposed in said actuator housing section.

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