Submersible electric double-screw pump with axial force hydraulic balance structure

Abstract

The utility model relates to the field of oil exploitation machinery, and discloses a submersible electric double-screw pump with an axial force hydraulic balance structure. The double-screw pump is provided with a hydraulic balance structure, the double-shaft submersible oil protector is provided with a multi-stage thrust bearing structure, the synchronous gear transmission mechanism is provided with a circulating cooling system, and the submersible oil universal joint and the submersible oil motor are sequentially connected in an integrated mode. The double-screw pump with the hydraulic balance structure comprises an interstage right-handed screw, an interstage left-handed screw and the like. The double-shaft submersible oil protector with the multi-stage thrust bearing structure comprises a protector driven shaft, a protector driving shaft, a bidirectional thrust assembly and the like. The synchronous gear transmission mechanism with the circulating cooling system comprises a driven gear, a driving gear, a circulating cooling oil pipe and the like. The utility model has the advantages of large range of lift and displacement, high system efficiency and long service life, and is suitable for heavy oil recovery, high-gas-content oil well recovery, high-sand-content oil well crude oil recovery and multi-phase medium mixed crude oil transportation.

Description

Technical Field

[0001] The utility model relates to the field of oil extraction machinery, and particularly relates to a submersible electric double screw pump with an axial force hydraulic balance structure. Background Art

[0002] Existing oil production equipment and oil production processes suitable for heavy oil wells include submersible electric single screw pumps or surface-driven single screw pumps, submersible electric centrifugal pump heavy oil production processes implementing viscosity reduction agent injection technology, pumping unit heavy oil production processes implementing steam injection heating technology, etc. For submersible electric single screw pumps or surface-driven single screw pumps, on the one hand, the displacement is small, and on the other hand, since their stators are made of rubber materials, they are not resistant to high temperatures and are prone to chemical reactions with sensitive gases (such as hydrogen sulfide, etc.) that may appear in the formation. Therefore, their application scope is limited. For submersible electric centrifugal pump heavy oil production processes implementing viscosity reduction agent injection technology and pumping unit heavy oil production processes implementing steam injection heating technology, due to the relatively high production costs and the complex surface equipment and pipe string structures, which increase the management and operation difficulties, their applications are also limited to a certain extent. Content of the Utility Model

[0003] To overcome the defects of the prior art, the utility model provides a submersible electric double screw pump with an axial force hydraulic balance structure, and its technical solution is as follows:

[0004] A submersible electric double screw pump with an axial force hydraulic balance structure, comprising a double screw pump with a hydraulic balance structure, a double shaft submersible protector with a multi-stage thrust bearing structure, a synchronous gear transmission mechanism with a circulating cooling system, a submersible universal joint and a submersible motor, which are integrally connected in sequence; the double screw pump with a hydraulic balance structure includes a pump discharge head, a pump head, a housing and a locking ring, an adjusting bushing, a top radial bearing assembly, a top radial bearing inner ring, an upper thrust limiting sleeve, a spiral casing, a last stage right-handed screw, a last stage left-handed screw, an upper bushing of the balance cavity, a clearance adjusting gasket, a first spline sleeve assembly, a balance cavity, a middle bushing of the balance cavity, an inter-stage radial bearing assembly, an inter-stage radial bearing inner ring, an inter-stage right-handed screw, an inter-stage left-handed screw, a variable diameter spline sleeve assembly, a radial bearing inner ring, a radial bearing assembly, and a suction bushing installed inside the housing; the double shaft submersible protector with a multi-stage thrust bearing structure includes a protector driven shaft, a protector driving shaft, a mechanical seal assembly, an upper mechanical seal seat assembly, a mechanical seal seat bushing, an upper seal pipe, a middle mechanical seal seat assembly, a lower seal pipe, a lower mechanical seal seat assembly, an upper thrust assembly, an upper thrust plate, a lower thrust plate, a two-way thrust assembly, a lower thrust assembly, a lower thrust bushing, a half-ring sleeve, an adjusting half-ring, two half-rings, a lower thrust bearing support bushing and a second spline sleeve assembly which are integrally installed; the synchronous gear transmission mechanism with a circulating cooling system includes a synchronous gear radial bearing, a synchronous gear upper bearing support assembly, a bearing support bushing, a driven gear, a driving gear, a driving gear support disc, a synchronous gear lower bearing support assembly, a bearing support bushing, a driven gear support disc, two half-rings, a bushing, a circulating cooling oil pipe, a circulating oil pump cylinder assembly, a single screw pump rotor, a compression pipe, a universal joint connecting joint, a centralizer assembly and a retaining ring which are integrally installed.

[0005] Further, the double screw pump with a hydraulic balance structure further includes connecting screws for connecting the pump discharge head and the pump head.

[0006] Further, the outer circle of the first spline sleeve assembly and the inner hole of the balance cavity cooperate to form a balance chamber.

[0007] Further, the inter-stage right-handed screw and the inter-stage left-handed screw are both provided with pressure transmission holes and radial pressure transmission holes; the number of stages of the inter-stage right-handed screw, the inter-stage left-handed screw and the spiral casing can be increased or decreased according to the required lifting head.

[0008] Further, the mechanical seal assembly is respectively installed at the upper end of the upper mechanical seal seat assembly, the lower end of the middle mechanical seal seat assembly and the lower end of the lower mechanical seal seat assembly; the upper thrust assembly, the upper thrust plate, the lower thrust plate, the two-way thrust assembly and the lower thrust assembly are sequentially installed at the lower end of the lower mechanical seal seat assembly, and the number of stages of the lower thrust assembly can be increased or decreased according to the magnitude of the axial force at the pump end.

[0009] Further, the upper mechanical seal seat assembly is provided with a first breathing hole and is matched with a first breathing pipe arranged; the middle mechanical seal seat assembly is provided with a second breathing hole, the upper part of which is matched with a second breathing pipe arranged, and the lower part of which is matched with a third breathing pipe arranged; the lower mechanical seal seat assembly is provided with a third breathing hole and is matched with a fourth breathing pipe arranged.

[0010] Further, the single screw pump rotor is installed at the lower end of the driven gear.

[0011] Further, the circulating oil pump cylinder block assembly is provided with a liquid discharge hole, a liquid discharge flow channel and is matched with a circulating cooling oil pipe.

[0012] Further, the twin screw pump with a hydraulic balance structure further includes a first O-ring and a second O-ring for sealing, and a first square key for installation; the double-shaft submersible protector with a multi-stage thrust bearing structure further includes a third O-ring and a fourth O-ring for sealing, and a second square key for installation; the synchronous gear transmission mechanism with a circulating cooling system further includes a third square key and a fourth square key for installation.

[0013] Further, the spline tooth profiles of the first spline sleeve assembly, the stepped spline sleeve assembly and the second spline sleeve assembly adopt cylindrical straight-tooth involute spline tooth profiles.

[0014] Compared with the prior art, the submersible electric twin screw pump with an axial force hydraulic balance structure provided by the present utility model mainly has the following advantages:

[0015] 1. The head and displacement ranges are large.

[0016] 2. The system efficiency is high.

[0017] 3. The working life is long.

[0018] 4. It can be widely applied to the petroleum exploitation process engineering, especially suitable for viscous oil exploitation, high gas content oil well exploitation and high sand content oil well crude oil exploitation.

[0019] 5. It is suitable for multi-phase medium mixed crude oil transportation.

[0020] 6. The structure is reasonable, safe and reliable, easy to manufacture, easy to maintain, and beneficial to popularization. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a schematic diagram of the overall layout structure of the present utility model;

[0022] Figure 1 (1) is Figure 1 an enlarged schematic diagram of the structure of the first part from top to bottom;

[0023] Figure 1 (2) is Figure 1Schematic enlarged view of the second part structure from top to bottom;

[0024] Figure 1 (3) is Figure 1 Schematic enlarged view of the third part structure from top to bottom;

[0025] In the figure: 1 - pump discharge head, 2 - connecting screw, 3 - first O-ring, 4 - pump head, 5 - second O-ring, 6 - locking ring, 7 - adjusting bushing, 8 - top radial bearing assembly, 9 - inner ring of top radial bearing, 10 - upper thrust limit sleeve, 11 - first square key, 12 - volute, 13 - last stage right-handed screw, 14 - last stage left-handed screw, 15 - upper bushing of balance cavity, 16 - clearance adjusting gasket, 17 - first splined bushing assembly, 18 - balance cavity, 19 - balance cavity body, 20 - middle bushing of balance cavity body, 21 - radial pressure transmission hole, 22 - inter-stage radial bearing assembly, 23 - inner ring of inter-stage radial bearing, 24 - housing, 25 - inter-stage right-handed screw, 26 - inter-stage left-handed screw, 27 - pressure transmission hole, 28 - stepped splined bushing assembly, 29 - inner ring of radial bearing, 30 - radial bearing assembly, 31 - suction bushing, 32 - driven shaft of protector, 33 - driving shaft of protector, 34 - mechanical seal assembly, 35 - upper mechanical seal seat assembly, 36 - first breathing hole, 37 - first breathing pipe, 38 - mechanical seal seat bushing, 39 - upper seal pipe, 40 - second breathing pipe, 41 - third O-ring, 42 - fourth O-ring, 43 - middle mechanical seal seat assembly, 44 - second breathing hole, 45 - third breathing pipe, 46 - lower seal pipe, 47 - fourth breathing pipe, 48 - third breathing hole, 49 - lower mechanical seal seat assembly, 50 - upper thrust assembly, 51 - upper thrust plate, 52 - lower thrust plate, 53 - bi-directional thrust assembly, 54 - lower thrust assembly, 55 - lower thrust bushing, 56 - half-ring sleeve, 57 - adjusting half-ring, 58 - two half-rings, 59 - second square key, 60 - lower thrust bearing support bushing, 61 - second splined bushing assembly, 62 - radial bearing of synchronizing gear, 63 - upper bearing support assembly of synchronizing gear, 64 - third square key, 65 - bearing support bushing, 66 - driven gear, 67 - driving gear, 68 - driving gear support disk, 69 - lower bearing support assembly of synchronizing gear, 70 - fourth square key, 71 - bearing support bushing, 72 - driven gear support disk, 73 - two half-rings, 74 - bushing, 75 - circulating cooling oil pipe, 76 - circulating oil pump cylinder assembly, 77 - single-screw pump rotor, 78 - liquid discharge flow channel, 79 - liquid discharge hole, 80 - compression pipe, 81 - universal joint connection joint, 82 - centralizer assembly, 83 - retaining ring, 84 - submersible universal joint, 85 - submersible motor. Specific embodiments

[0026] The present utility model will be described in detail below in conjunction with the embodiments and the drawings. Embodiment 1

[0027] See Figure 1 、 Figure 1 (1)、 Figure 1 (2)and Figure 1 (3). A submersible electric twin screw pump with an axial force hydraulic balance structure includes a twin screw pump with a hydraulic balance structure, a two-shaft submersible protector with a multi-stage thrust bearing structure, a synchronous gear transmission mechanism with a circulating cooling system, a submersible universal joint 84, and a submersible motor 85 that are integrally and sequentially connected; the twin screw pump with a hydraulic balance structure includes a pump discharge head 1, a pump head 4, a housing 24, and a locking ring 6, an adjusting bushing 7, a top radial bearing assembly 8, a top radial bearing inner ring 9, an upper thrust limit sleeve 10, a spiral casing 12, a last-stage right-handed screw 13, a last-stage left-handed screw 14, an upper bushing of the balance cavity 15, a clearance adjusting gasket 16, a first spline sleeve assembly 17, a balance cavity 19, a middle bushing of the balance cavity 20, an inter-stage radial bearing assembly 22, an inter-stage radial bearing inner ring 23, an inter-stage right-handed screw 25, an inter-stage left-handed screw 26, a variable-diameter spline sleeve assembly 28, a radial bearing inner ring 29, a radial bearing assembly 30, an intake bushing 31 installed inside the housing 24; the two-shaft submersible protector with a multi-stage thrust bearing structure includes a protector driven shaft 32, a protector driving shaft 33, a mechanical seal assembly 34, an upper mechanical seal seat assembly 35, a mechanical seal seat bushing 38, an upper seal pipe 39, a middle mechanical seal seat assembly 43, a lower seal pipe 46, a lower mechanical seal seat assembly 49, an upper thrust assembly 50, an upper thrust plate 51, a lower thrust plate 52, a two-way thrust assembly 53, a lower thrust assembly 54, a lower thrust bushing 55, a half-ring sleeve 56, an adjusting half-ring 57, two half-rings 58, a lower thrust bearing support bushing 60, and a second spline sleeve assembly 61 that are integrally installed; the synchronous gear transmission mechanism with a circulating cooling system includes a synchronous gear radial bearing 62, a synchronous gear upper bearing support assembly 63, a bearing support bushing 65, a driven gear 66, a driving gear 67, a driving gear support disk 68, a synchronous gear lower bearing support assembly 69, a bearing support bushing 71, a driven gear support disk 72, two half-rings 73, a bushing 74, a circulating cooling oil pipe 75, a circulating oil pump cylinder assembly 76, a single screw pump rotor 77, a compression pipe 80, a universal joint connecting joint 81, a centralizer assembly 82, and a retaining ring 83 that are integrally installed. Embodiment 2

[0028] See Figure 1 、 Figure 1 (1)、 Figure 1 (2)and Figure 1(3). A submersible electric double screw pump with an axial force hydraulic balance structure. Based on the technical solution described in Embodiment 1, the double screw pump with a hydraulic balance structure further includes a connecting screw 2, which is used to connect the pump discharge head 1 and the pump head 4; the outer circle of the first spline sleeve assembly 17 cooperates with the inner hole of the balance cavity 19 to form a balance chamber 18; both the inter-stage right-handed screw 25 and the inter-stage left-handed screw 26 are provided with a pressure transmission hole 27 and a radial pressure transmission hole 21; the number of stages of the inter-stage right-handed screw 25, the inter-stage left-handed screw 26, and the spiral casing 12 can be increased or decreased according to the required lifting head. Embodiment 3

[0029] See Figure 1 and Figure 1 (1), Figure 1 (2) and Figure 1 (3). A submersible electric double screw pump with an axial force hydraulic balance structure. Based on the technical solution described in Embodiment 1, the mechanical seal assembly 34 is respectively installed at the upper end of the upper mechanical seal seat assembly 35, the lower end of the middle mechanical seal seat assembly 43, and the lower end of the lower mechanical seal seat assembly 49; the upper thrust assembly 50, the upper thrust plate 51, the lower thrust plate 52, the bi-directional thrust assembly 53, and the lower thrust assembly 54 are sequentially installed at the lower end of the lower mechanical seal seat assembly 49, and the number of stages of the lower thrust assembly 54 can be increased or decreased according to the magnitude of the axial force at the pump end. Embodiment 4

[0030] See Figure 1 and Figure 1 (1), Figure 1 (2) and Figure 1 (3). A submersible electric double screw pump with an axial force hydraulic balance structure. Based on the technical solution described in Embodiment 1, the upper mechanical seal seat assembly 35 is provided with a first breathing hole 36, which is matched with the provided first breathing pipe 37; the middle mechanical seal seat assembly 43 is provided with a second breathing hole 44, the upper part of which is matched with the provided second breathing pipe 40, and the lower part of which is matched with the provided third breathing pipe 45; the lower mechanical seal seat assembly 49 is provided with a third breathing hole 48 and is matched with the provided fourth breathing pipe 47. Embodiment 5

[0031] See Figure 1 and Figure 1 (1), Figure 1 (2) and Figure 1 (3). A submersible electric double screw pump with an axial force hydraulic balance structure. Based on the technical solution described in Embodiment 1, the single screw pump rotor 77 is installed at the lower end of the driven gear 66; the circulating oil pump cylinder block assembly 76 is provided with a liquid discharge hole 79, a liquid discharge flow channel 78, and is matched with the circulating cooling oil pipe 75. Embodiment 6

[0032] See Figure 1 、 Figure 1 (1)、 Figure 1 (2) and Figure 1 (3). A submersible electric double screw pump with an axial force hydraulic balance structure, based on the technical solution described in Embodiment 1, the double screw pump with a hydraulic balance structure further includes a first O-ring 3 and a second O-ring 5 for sealing, and a first square key 11 for installation; the double-shaft submersible protector with a multi-stage thrust bearing structure further includes a third O-ring 41 and a fourth O-ring 42 for sealing, and a second square key 59 for installation; the synchronous gear transmission mechanism with a circulating cooling system further includes a third square key 64 and a fourth square key 70 for installation. Embodiment 7

[0033] See Figure 1 、 Figure 1 (1)、 Figure 1 (2) and Figure 1 (3). A submersible electric double screw pump with an axial force hydraulic balance structure, based on the technical solution described in Embodiment 1, the spline tooth profiles of the first spline sleeve assembly 17, the stepped spline sleeve assembly 28, and the second spline sleeve assembly 61 adopt cylindrical straight-tooth involute spline tooth profiles.

[0034] To enable those skilled in the art to better understand the present invention, the basic working principle of the present invention is briefly introduced as follows:

[0035] When the submersible motor 85 rotates forward (viewed from the bottom of the motor upwards, the motor rotates clockwise), the submersible motor 85 drives the driving gear 67 and the driven gear 66 to rotate synchronously through the submersible universal joint 84. The driving gear 67 and the driven gear 66 drive the protector driving shaft 33 and the protector driven shaft 32 to rotate synchronously through the second spline sleeve assembly 61. The protector driving shaft 33 and the protector driven shaft 32 drive the inter-stage left-handed screw 26 and the inter-stage right-handed screw 25 to rotate synchronously through the stepped spline sleeve assembly 28. When the inter-stage left-handed screw 26 and the inter-stage right-handed screw 25 rotate synchronously in opposite directions, the well fluid in the closed space formed by their tooth grooves and the screw housing 12 is discharged upwards to the ground stage by stage, so as to achieve the purpose of oil extraction.

[0036] The inter-stage left-handed screw 26 and the inter-stage right-handed screw 25 transfer the high pressure at the output end of each stage of the screw pump to the corresponding balance cavity 18 through the radial pressure transmission holes 21 and the pressure transmission holes 27, so as to generate an upward thrust to balance most of the axial force. The remaining axial force is then transferred to the two-way thrust assembly 53 and the lower thrust assembly 54 through the inter-stage left-handed screw 26 and the inter-stage right-handed screw 25, the protector driving shaft 33 and the protector driven shaft 32, thereby achieving the balance of the axial force.

[0037] The dual-shaft submersible protector with a multi-stage thrust bearing structure has three functions. First, it isolates well fluid to prevent the well fluid from directly entering the motor. Second, it balances the pressure between the inside of the motor and the wellbore, compensating for the expansion and contraction of the motor oil caused by temperature changes. Third, it balances the remaining axial force from the pump end.

[0038] The synchronous gear transmission mechanism with a circulating cooling system, in addition to transmitting the power from the motor through the synchronous gears, also makes the motor oil inside the synchronous gear transmission mechanism circulate through the circulating cooling oil pipe 75 by the rotation of the single-screw pump rotor 77 at the lower end of the driven gear 66, playing a role in cooling the gears in the synchronous gear transmission mechanism and the multi-stage thrust bearings in the dual-shaft submersible protector.

Claims

1. A submersible electric twin-screw pump with an axial force hydraulic balance structure, comprising a twin-screw pump with a hydraulic balance structure, a double-axis submersible protector with a multi-stage thrust bearing structure, a synchronous gear transmission mechanism with a circulating cooling system, a submersible universal joint and a submersible motor, characterized in that: The twin-screw pump with a hydraulic balance structure includes a pump discharge head, a pump head, a housing and a locking ring installed inside the housing, an adjustment bushing, a top radial bearing assembly, a top radial bearing inner ring, an upper thrust limit sleeve, a screw shell, a last-stage right-handed screw, a last-stage left-handed screw, an upper bushing of a balance chamber, a gap adjustment gasket, a first spline sleeve assembly, a balance chamber, a middle bushing of a balance chamber, an interstage radial bearing assembly, an interstage radial bearing inner ring, an interstage right-handed screw, an interstage left-handed screw, a reducing spline sleeve assembly, a radial bearing inner ring, a radial bearing assembly, and a suction bushing; the twin-shaft submersible protector with a multi-stage thrust bearing structure includes an integrally installed protector driven shaft, a protector active shaft, a mechanical seal assembly, an upper mechanical seal seat assembly, and a mechanical seal seat bushing , upper sealing tube, middle mechanical seal seat assembly, lower sealing tube, lower mechanical seal seat assembly, upper thrust assembly, upper thrust plate, lower thrust plate, bidirectional thrust assembly, lower thrust assembly, lower thrust bushing, half ring sleeve, adjustment half ring, two half rings, lower thrust bearing support bushing and second spline sleeve assembly; the synchronous gear transmission mechanism with a circulating cooling system includes an integrated synchronous gear radial bearing, a synchronous gear upper bearing support assembly, a bearing support bushing, a driven gear, a driving gear, a driving gear support plate, a synchronous gear lower bearing support assembly, a bearing support bushing, a driven gear support plate, two half rings, a bushing, a circulating cooling oil pipe, a circulating oil pump cylinder assembly, a single screw pump rotor, a clamping pipe, a universal joint connection joint, a straightening ring assembly and a retaining ring.

2. The submersible electric twin-screw pump with an axial force hydraulic balance structure according to claim 1, characterized in that: The twin-screw pump with a hydraulic balance structure also includes a connecting screw, which is used to connect the pump discharge head and the pump head.

3. The submersible electric twin-screw pump with an axial force hydraulic balance structure according to claim 1, characterized in that: The outer circle of the first spline sleeve assembly cooperates with the inner hole of the balancing cavity to form a balancing cavity.

4. The submersible electric twin-screw pump with an axial force hydraulic balance structure according to claim 1, characterized in that: The interstage right-handed screw and the interstage left-handed screw are both provided with pressure transmission holes and radial pressure transmission holes; the number of interstage right-handed screws, interstage left-handed screws and screw shells can be increased or decreased according to the required lifting head.

5. The submersible electric twin-screw pump with an axial force hydraulic balance structure according to claim 1, characterized in that: The mechanical seal assemblies are respectively installed on the upper end of the upper mechanical seal seat assembly, the lower end of the middle mechanical seal seat assembly and the lower end of the lower mechanical seal seat assembly; the upper thrust assembly, the upper thrust plate, the lower thrust plate, the two-way thrust assembly and the lower thrust assembly are sequentially installed on the lower end of the lower mechanical seal seat assembly, and the number of stages of the lower thrust assembly can be increased or decreased according to the size of the axial force at the pump end.

6. The submersible electric twin-screw pump with an axial force hydraulic balance structure according to claim 1, characterized in that: The upper mechanical seal seat assembly is provided with a first breathing hole, and cooperates with the first breathing tube; the middle mechanical seal seat assembly is provided with a second breathing hole, the upper part of which cooperates with the second breathing tube, and the lower part of which cooperates with the third breathing tube; the lower mechanical seal seat assembly is provided with a third breathing hole, and cooperates with the fourth breathing tube.

7. The submersible electric twin-screw pump with an axial force hydraulic balance structure according to claim 1, characterized in that: The single screw pump rotor is installed at the lower end of the driven gear.

8. The submersible electric twin-screw pump with an axial force hydraulic balance structure according to claim 1, characterized in that: The circulating oil pump cylinder assembly is provided with a drainage hole and a drainage channel and is matched with a circulating cooling oil pipe.

9. The submersible electric twin-screw pump with an axial force hydraulic balance structure according to claim 1, characterized in that: The twin-screw pump with a hydraulic balance structure also includes a first O-ring and a second O-ring for sealing, and a first square key for installation; the dual-axis submersible protector with a multi-stage thrust bearing structure also includes a third O-ring and a fourth O-ring for sealing, and a second square key for installation; the synchronous gear transmission mechanism with a circulating cooling system also includes a third key and a fourth square key for installation.

10. The submersible electric twin-screw pump with an axial force hydraulic balance structure according to claim 1, characterized in that: The spline tooth profiles of the first spline sleeve assembly, the reducing spline sleeve assembly and the second spline sleeve assembly adopt cylindrical spur involute spline tooth profiles.

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