CN113123950A

CN113123950A - Submersible electric plunger pump

Info

Publication number: CN113123950A
Application number: CN201911419873.5A
Authority: CN
Inventors: 黄晓东; 姚金杭; 雷德荣; 张辉; 张传新; 陈瑞祥; 米娜瓦尔·吐尔逊; 蒋理; 迪力夏提·吐尔逊; 巴克·海肉拉; 夏甫开提·米吉提
Original assignee: Petrochina Co Ltd
Current assignee: Petrochina Co Ltd
Priority date: 2019-12-31
Filing date: 2019-12-31
Publication date: 2021-07-16
Anticipated expiration: 2039-12-31
Also published as: CN113123950B

Abstract

The invention provides an oil-submersible electric plunger pump, which comprises a motor component, wherein a motor rotor of the motor component does reciprocating linear motion; the first end of the sieve tube of the outer cylinder component is connected with the motor stator, and the second end of the sieve tube is connected with the first end of the outer cylinder structure; the traveling valve assembly of the pump barrel assembly is connected with the second end of the motor rotor, and the traveling valve assembly is connected with the first end of the pump barrel structure; the first end of the plunger structure of the plunger component is connected with the fixed valve assembly, and the second end of the plunger structure is connected with the second end of the outer barrel structure; the pump barrel assembly is located in the barrel of the outer barrel assembly, the first end of the fixed valve assembly and the plunger structure is located in the barrel of the pump barrel assembly, and the inner diameter of the pump barrel structure is matched with the outer diameter of the first end of the plunger structure. The technical scheme of this embodiment has solved among the prior art oily electric plunger pump under the condition that does not increase the pump footpath, the less problem of area of overflowing of oily electric plunger pump.

Description

Submersible electric plunger pump

Technical Field

The invention relates to the technical field of oil exploitation equipment, in particular to an electric submersible plunger pump.

Background

In recent years, with the increasing demand of petroleum resources, the exploitation equipment in the petroleum exploitation industry is diversified more and more, so as to adapt to different exploitation environments and improve the exploitation efficiency.

In the prior art, an oil pumping pump system is mostly used for lifting petroleum, a power device of the oil pumping pump system is an oil pumping unit, the oil pumping unit is commonly called a head knocking machine, and an oil pumping rod of the oil pumping unit reciprocates in an oil well, so that oil is continuously lifted and pumped out. But because the sucker rod and the oil pipe have friction, the sucker rod, the oil pipe and the like are easy to wear, the sucker rod, the oil pipe and the like are not suitable for horizontal wells and large-inclination directional wells, the adopted speed and other parameters can not be adjusted conveniently, and the packing box using the flange plate at the oil outlet of the pumping unit is easy to leak oil. In addition, in the prior art, the submersible electric plunger pump is applied to a certain scale on an oil field site as a power device of an oil extraction system. The submersible electric plunger pump mainly comprises a submersible linear motor system and an oil pumping pump system. The submersible linear motor system directly converts electric energy into reciprocating linear motion, and the oil pumping pump system lifts liquid at the well bottom to the well head. A rotor push rod of an oil-submersible linear motor system in the oil-submersible electric plunger pump is directly connected with a plunger of an oil well pump system, a stator of the oil-submersible linear motor system is connected with a pump barrel of the oil well pump system, namely, the oil-submersible linear motor and the oil well pump are connected on the ground and then are put into a well through an oil pipe.

The submersible electric plunger pump is mainly applied to thin oil wells and thick oil wells, and because the underground liquid inlet enters through a traveling valve (the valve is a one-way ball valve which can discharge liquid in the pump along with the plunger or a pump cylinder in a reciprocating motion), then enters into the inner diameter of the plunger and then enters into the pump cylinder, because the flowing area of the traveling valve is small, the friction resistance between oil and an overflowing channel is large, and the pump efficiency is influenced.

At present, in order to increase the oil lifting efficiency of an oil-submersible electric plunger pump, the flow area of a floating valve in the oil-submersible electric plunger pump needs to be increased, but the existing solution is to increase the pump diameter of the oil-submersible electric plunger pump and then increase the diameter of the floating valve. The structure is changed, on one hand, the outer diameter of the submersible electric plunger pump is increased, and the small casing oil well cannot be put into the oil well; on the other hand, the lifting thrust and the power of the linear motor of the submersible electric plunger pump are increased, the running depth of the submersible electric plunger pump is influenced, and the application range of the submersible electric plunger pump is reduced.

Disclosure of Invention

The invention mainly aims to provide an electric submersible plunger pump, which solves the problem that the overflowing area of the electric submersible plunger pump is small under the condition that the pump diameter is not increased in the prior art.

In order to achieve the purpose, the invention provides an oil-submersible electric plunger pump which comprises a motor assembly, wherein the motor assembly comprises a motor stator, a motor rotor and a cable, the first end of the motor rotor is arranged in the motor stator in a penetrating manner, the cable is electrically connected with the motor stator, and the motor rotor does reciprocating linear motion; the motor stator is characterized by further comprising an outer barrel component, wherein the outer barrel component comprises a sieve pipe and an outer barrel structure, the first end of the sieve pipe is connected with the motor stator, and the second end of the sieve pipe is connected with the first end of the outer barrel structure; the pump cylinder assembly comprises a pump cylinder structure and a traveling valve assembly, wherein the first end of the traveling valve assembly is connected with the second end of the motor rotor, and the second end of the traveling valve assembly is connected with the first end of the pump cylinder structure; the plunger component comprises a fixed valve assembly and a plunger structure, wherein the first end of the plunger structure is connected with the fixed valve assembly, and the second end of the plunger structure is connected with the second end of the outer barrel structure; the pump barrel assembly is located in the barrel of the outer barrel assembly, the first end of the fixed valve assembly and the plunger structure is located in the barrel of the pump barrel assembly, and the inner diameter of the pump barrel structure is matched with the outer diameter of the first end of the plunger structure.

Further, the outer barrel structure comprises a joint and an outer working barrel, wherein the first end of the outer working barrel is connected with the second end of the sieve tube, and the second end of the outer working barrel is connected with the first end of the joint.

Further, the submersible electric plunger pump further comprises an oil pipe, and the oil pipe is connected with the second end of the joint.

Furthermore, the plunger structure includes a plunger suspension cylinder and a plunger sleeve, a first end of the plunger sleeve is connected with the fixed valve assembly, a second end of the plunger sleeve is connected with a first end of the plunger suspension cylinder, and a second end of the plunger suspension cylinder is connected with the joint.

Further, the second end of the plunger suspension barrel is connected with the inner wall of the joint at the middle position.

Further, the second end of the pump barrel structure is located between the first end of the plunger suspension barrel and the second end of the plunger suspension barrel, the second end of the pump barrel structure having an inward flange.

Further, the inner diameter of the pump barrel structure is clearance fit with the outer diameter of the first end of the plunger structure.

Further, an oil inlet channel is arranged on the side face of the first end of the traveling valve assembly, the plunger structure 42 is of a cylindrical structure, and the area of the oil inlet channel is larger than the sectional area of the plunger structure.

Further, the side surface of the screen pipe is provided with an oil inlet passage for communicating the inner space of the outer cylinder assembly and the outer space of the outer cylinder assembly.

Furthermore, the submersible electric plunger pump further comprises a centralizer, wherein the centralizer is arranged on the motor stator and is positioned on one side, far away from the motor rotor, of the motor stator.

When the technical scheme of the invention is applied, when the submersible electric plunger pump is used for pumping oil, the submersible electric plunger pump is put into an oil well casing, the motor component drives the motor rotor to do downstroke motion, the motor rotor drives the pump barrel component to do retreating motion, at the moment, the fixed valve assembly is closed under the pressure effect of the oil pipe, the floating valve assembly is opened under the pressure effect of an oil layer, and oil enters a cavity between the pump barrel component and the plunger component. When the motor component drives the motor rotor to do an upward stroke action, the motor rotor drives the pump barrel component to do an advancing action, so that the pressure of oil entering a cavity between the pump barrel component and the plunger component rises, the traveling valve assembly is closed, the oil cannot flow back, the pressure of the oil entering the cavity between the pump barrel component and the plunger component further rises, the fixed valve assembly is opened, and then the oil is discharged from the submersible electric plunger pump sequentially through the fixed valve assembly and the plunger structure. The up-down stroke, the forward movement and the backward movement of the motor rotor are continuously and repeatedly carried out, so that the continuous oil pumping and lifting work of the submersible electric plunger pump can be realized, and the oil at the well bottom is lifted to the well head through an oil pipe. In addition, the pump barrel assembly is arranged in the barrel of the outer barrel assembly, the first end of the plunger assembly is arranged in the barrel of the pump barrel assembly, the diameter of the traveling valve assembly is larger than that of the fixed valve assembly due to the nested structure, and therefore the diameter of the traveling valve assembly is increased relative to that of the fixed valve assembly, the flow area of the traveling valve assembly is increased relatively, the oil lifting efficiency is improved, and the pump diameter of the submersible electric plunger pump cannot be increased. The technical scheme of the invention effectively solves the problem that the flow area of the submersible electric plunger pump is smaller under the condition that the pump diameter of the submersible electric plunger pump in the prior art is not increased.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:

fig. 1 shows a schematic overall structural view of an embodiment of the submersible electric plunger pump according to the present invention.

Wherein the figures include the following reference numerals:

10. a motor assembly; 11. a motor stator; 12. a motor rotor; 13. a cable; 20. an outer barrel assembly; 21. a screen pipe; 22. an outer barrel structure; 221. a joint; 222. an outer working barrel; 30. a pump barrel assembly; 31. a pump barrel structure; 32. a swimming valve assembly; 40. a plunger assembly; 41. fixing the valve assembly; 42. a plunger structure; 421. a plunger suspension barrel; 422. a plunger sleeve; 50. an oil pipe; 60. a centralizer; 70. a sleeve.

Detailed Description

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.

It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

Spatially relative terms, such as "above … …," "above … …," "above … …," "above," and the like, may be used herein for ease of description to describe one device or feature's spatial relationship to another device or feature as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if a device in the figures is turned over, devices described as "above" or "on" other devices or configurations would then be oriented "below" or "under" the other devices or configurations. Thus, the exemplary term "above … …" can include both an orientation of "above … …" and "below … …". The device may be otherwise variously oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

Exemplary embodiments according to the present application will now be described in more detail with reference to the accompanying drawings. These exemplary embodiments may, however, be embodied in many different forms and should not be construed as limited to only the embodiments set forth herein. It is to be understood that these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the exemplary embodiments to those skilled in the art, in the drawings, the thicknesses of layers and regions are exaggerated for clarity, and the same devices are denoted by the same reference numerals, and thus the description thereof will be omitted.

As shown in fig. 1, the submersible electric plunger pump of the present embodiment includes: the motor assembly 10, the motor assembly 10 includes the motor stator 11, the motor mover 12 and the cable 13, the first end of the motor mover 12 is worn and set up in the motor stator 11, the cable 13 is electrically connected with motor stator 11, the motor mover 12 makes the reciprocating linear motion; the motor stator structure further comprises an outer cylinder component 20, wherein the outer cylinder component 20 comprises a sieve pipe 21 and an outer cylinder structure 22, a first end of the sieve pipe 21 is connected with the motor stator 11, and a second end of the sieve pipe 21 is connected with a first end of the outer cylinder structure 22; the pump cylinder assembly 30, the pump cylinder assembly 30 includes a pump cylinder structure 31 and a traveling valve assembly 32, a first end of the traveling valve assembly 32 is connected with a second end of the motor mover 12, and a second end of the traveling valve assembly 32 is connected with a first end of the pump cylinder structure 31; the plunger assembly 40, the plunger assembly 40 includes the fixed valve assembly 41 and the plunger structure 42, the first end of the plunger structure 42 is connected with the fixed valve assembly 41, the second end of the plunger structure 42 is connected with the second end of the outer cylinder structure 22; the pump barrel assembly 30 is located in the barrel of the outer barrel assembly 20, the first ends of the fixed valve assembly 41 and the plunger structure 42 are located in the barrel of the pump barrel assembly 30, and the inner diameter of the pump barrel structure 31 is matched with the outer diameter of the first end of the plunger structure 42.

It should be noted that the motor assembly 10 may be a linear motor, a hydraulic push rod, or other driving devices capable of realizing reciprocating linear motion. The diameter of the traveling valve assembly 32 is larger than that of the fixed valve assembly 41, so that the oil passing area of the oil inlet channel is relatively increased, the flow passing area of the traveling valve assembly 32 is relatively increased, the frictional resistance is reduced, and the efficiency of the pump is improved. The fixed valve assembly 41 is arranged in the pump barrel assembly 30, the diameter of the fixed valve assembly 41 is reduced compared with the original diameter, although the diameter reduction of the fixed valve assembly 41 can increase a certain frictional resistance, because the diameter of the floating valve assembly 32 is larger than that of the fixed valve assembly 41, the passing amount of oil liquid is relatively increased, the frictional resistance of the fixed valve assembly 41 can be overcome by means of the thrust of the motor rotor, and therefore the efficiency of the pump is not influenced.

As shown in fig. 1, in the solution of this embodiment, the outer cylinder structure 22 includes a joint 221 and an outer cylinder 222, a first end of the outer cylinder 222 is connected to the second end of the screen 21, and a second end of the outer cylinder 222 is connected to the first end of the joint 221. The joint 221 is an oil outlet for connecting the external oil pipe 50 and mounting the outer barrel assembly. The outer working barrel 222 plays a role in protecting and fixing the internal structure, a gap is formed between the inner wall of the outer working barrel 222 and the outer wall of the pump barrel structure 31, the motion of the pump barrel is not limited, and the outer working barrel 222 can play a role in guiding the pump barrel structure 31. The connection between the connector 221, the outer barrel 222 and the screen 21 can be made by a screw fit, and the connection between the screen 21 and the motor stator 11 can be made by a screw fit.

As shown in fig. 1, in the solution of this embodiment, the submersible electric plunger pump further includes an oil pipe 50, and the oil pipe 50 is connected to the second end of the joint 221. The oil pipe 50 is used for conveying oil lifted by the submersible electric plunger pump to the surface. The oil pipe 50 and the joint 221 can be connected through thread matching, and the oil pipe is in threaded connection and has sealing performance, so that the oil liquid is guaranteed to have a good transmission effect.

As shown in fig. 1, in the present embodiment, the plunger structure 42 includes a plunger suspension cylinder 421 and a plunger sleeve 422, a first end of the plunger sleeve 422 is connected to the fixed valve assembly 41, a second end of the plunger sleeve 422 is connected to the first end of the plunger suspension cylinder 421, and a second end of the plunger suspension cylinder 421 is connected to the joint 221. The plunger suspension cylinder 421 and the plunger sleeve 422 are oil passages, and the plunger sleeve 422 is used for installing the fixed valve assembly 41. The first end of the plunger suspension cylinder 421 extends into the pump cylinder structure 31, so that the length of the outer pump cylinder structure 31 can be increased, and the pump cylinder structure 31 does not collide with the inner plunger sleeve 422 during movement, thereby protecting the structural components. The plunger structure and the pump barrel structure are in clearance fit.

As shown in fig. 1, in the solution of the present embodiment, the second end of the plunger suspension cylinder 421 is connected to the inner wall of the joint 221 at the middle position. The structure enables the oil outlet position of the submersible electric plunger pump to have a good sealing effect.

In the present embodiment, as shown in fig. 1, the second end of the pump barrel structure 31 is located between the first end of the plunger suspension barrel 421 and the second end of the plunger suspension barrel 421, and the second end of the pump barrel structure 31 has an inward flange. The inside diameter of the flange is larger than the outside diameter of the plunger suspension cylinder 421 and smaller than the outside diameter of the plunger sleeve 422, so that the plunger sleeve 422 limits the pump cylinder structure 31.

In the present embodiment, as shown in fig. 1, the inner diameter of the cylinder structure 31 is in clearance fit with the outer diameter of the first end of the plunger structure 42. The outer wall of the cylinder body of the plunger sleeve 422 is in clearance fit with the inner wall of the pump cylinder structure 31, so that most of oil passes through the fixed valve assembly 41, and the oil loss from the clearance can be ignored.

As shown in fig. 1, in the technical solution of this embodiment, an oil inlet passage is provided on a side surface of the first end of the traveling valve assembly 32, the plunger structure 42 is a cylindrical structure, and an area of the oil inlet passage is larger than a sectional area of the plunger structure 42. The oil inlet channel on the traveling valve assembly 32 is communicated with the cavity between the sieve tube 21 and the pump barrel assembly 30, and the friction resistance is reduced by increasing the diameter of the traveling valve assembly 32, so that the cavity between the pump barrel assembly 30 and the plunger assembly 40 can be filled with oil through the traveling valve assembly 32, and the oil lifting efficiency is well ensured.

As shown in fig. 1, in the solution of the present embodiment, the side surface of the screen 21 has an oil inlet passage for communicating the inner space of the outer cylinder assembly 20 and the outer space of the outer cylinder assembly 20. The oil inlet passage facilitates the entry of oil from the sleeve 70 into the cavity of the outer barrel construction 22 in preparation for further processing. In addition, the oil inlet channel of the sieve tube 21 can be a plurality of through holes for oil to enter the outer cylinder structure 22, a filter screen can be arranged on the surface of the sieve tube 21, and the oil is pre-filtered through the filter screen, so that the submersible electric plunger pump is protected.

As shown in fig. 1, in the technical solution of this embodiment, the submersible electric plunger pump further includes a centralizer 60, where the centralizer 60 is disposed on the motor stator 11 and is located on a side of the motor stator 11 away from the motor mover 12. The centralizer 60 mainly centralizes the motor stator 11 to prevent the cable 13 from colliding with the sleeve 70, and after the cable 13 is electrified, the motor rotor 12 moves up and down in the motor stator 11. In addition, the outer diameter of the centralizer 60 is larger than that of the motor stator 11, so that the cable 13 is positioned in the space formed between the centralizer 60 and the casing 70, the abrasion between the cable 13 and the wall of the casing 70 is well reduced, and the cable 13 is effectively protected.

It should be noted that, the joints in the above structures can all adopt a thread fit connection mode, so as to ensure the stability of the structure and better sealing effect. The stroke of the motor mover 12 is the same as the stroke length of the pump barrel assembly 30, and the length of the pump barrel structure 31 can be set according to actual conditions, so that the pump barrel structure 31 and the plunger assembly 40 do not collide when moving with each other. When the motor rotor 12 runs in an overtravel mode, pump collision operation can be carried out, the fixed valve assembly and the traveling valve assembly collide with each other, wax, sand and the like deposited on the pump cylinder assembly 30 and the plunger assembly 40 are vibrated down, the influence of the wax, the sand and the like on the fixed valve assembly 41 and the traveling valve assembly 32 is reduced, and the working reliability of the oil well pump system is effectively improved. The over-travel operation of the motor mover 12 may be turned on and off by a remote control system. In addition, the submersible electric plunger pump can still effectively ensure that the application range of the submersible electric plunger pump is not influenced because the pump diameter is not increased.

It should be further noted that a valve (valve in english, and valve in chinese) has an action effect similar to a one-way valve, and generally comprises a valve outer housing, and an internal valve ball and a valve ball seat, when a fluid passes through the valve, the valve ball leaves the valve ball seat, a flow passage is opened, the fluid can pass through, when the fluid flows in a reverse direction, the valve ball sits on the valve ball seat under the action of pressure (or other force), the flow passage is closed, the fluid cannot pass through the valve, and a valve is often used on a pump, especially a multi-plunger pump, to ensure the one-way flow of the fluid. The traveling valve is a one-way ball valve which is mounted on the plunger of the oil-well pump and can make reciprocating motion with the plunger in the construction process so as to discharge the liquid in the pump. The fixed valve means that the installation position is fixed, and only the distance and the close movement between the valve ball and the valve ball seat are needed. In addition, because the submersible electric plunger pump is not limited by a sucker rod of the oil pumping unit, the submersible electric plunger pump not only can be deeply buried into a vertical well, but also can be deeply buried into a horizontal well. After the submersible electric plunger pump is placed in the well, the outer barrel assembly 20 will not substantially move any more, so the submersible electric plunger pump will not substantially wear with the well casing. Compared with a pumping unit as a power device, the submersible electric plunger pump has the following advantages: (1) the energy-saving effect is obvious; (2) the sucker rod is not present, the eccentric wear problem of the pipe and the rod is avoided, and the sucker rod is more suitable for a directional well; (3) intelligent control can be realized, and parameters of the submersible electric plunger pump can be adjusted by utilizing a button in the ground control cabinet, so that the parameters can be adjusted simply and conveniently; (4) if the remote monitoring system is matched, the functions of remote monitoring and operation can be realized; (5) the use of electric drive is more environment-friendly; (6) the linear motor is used for driving the reciprocating type submersible pump to pump oil, the packing box sealing problem of the pumping unit sucker rod pump lifting technology does not exist, and therefore the problem of oil leakage at the packing box is solved.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.

It should be noted that the terms "first," "second," and the like in the description and claims of this application and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the application described herein are, for example, capable of operation in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. The submersible electric plunger pump comprises a motor assembly (10), wherein the motor assembly (10) comprises a motor stator (11), a motor rotor (12) and a cable (13), the first end of the motor rotor (12) penetrates through the motor stator (11), the cable (13) is electrically connected with the motor stator (11), and the motor rotor (12) makes reciprocating linear motion;

it is characterized by also comprising:

the outer cylinder assembly (20), the outer cylinder assembly (20) comprises a sieve tube (21) and an outer cylinder structure (22), a first end of the sieve tube (21) is connected with the motor stator (11), and a second end of the sieve tube (21) is connected with a first end of the outer cylinder structure (22);

the motor rotor comprises a pump barrel assembly (30), wherein the pump barrel assembly (30) comprises a pump barrel structure (31) and a traveling valve assembly (32), a first end of the traveling valve assembly (32) is connected with a second end of the motor rotor (12), and a second end of the traveling valve assembly (32) is connected with a first end of the pump barrel structure (31);

the plunger assembly (40), the plunger assembly (40) includes a fixed valve assembly (41) and a plunger structure (42), a first end of the plunger structure (42) is connected with the fixed valve assembly (41), and a second end of the plunger structure (42) is connected with a second end of the outer barrel structure (22);

the pump barrel assembly (30) is located in the barrel of the outer barrel assembly (20), the first ends of the fixed valve assembly (41) and the plunger structure (42) are located in the barrel of the pump barrel assembly (30), and the inner diameter of the pump barrel structure (31) is matched with the outer diameter of the first end of the plunger structure (42).

2. The submersible electric plunger pump according to claim 1, characterized in that the outer cylinder structure (22) comprises a joint (221) and an outer cylinder (222), a first end of the outer cylinder (222) being connected to a second end of the screen (21), a second end of the outer cylinder (222) being connected to a first end of the joint (221).

3. The submersible electric plunger pump of claim 2, further comprising an oil pipe (50), the oil pipe (50) being connected to the second end of the joint (221).

4. The submersible electric plunger pump according to claim 2, characterized in that the plunger structure (42) comprises a plunger suspension cylinder (421) and a plunger sleeve (422), a first end of the plunger sleeve (422) is connected to the fixed valve assembly (41), a second end of the plunger sleeve (422) is connected to the first end of the plunger suspension cylinder (421), and a second end of the plunger suspension cylinder (421) is connected to the joint (221).

5. The submersible electric plunger pump according to claim 4, characterized in that the second end of the plunger suspension cylinder (421) is connected to the inner wall of the joint (221) in the middle position.

6. The submersible electric plunger pump according to claim 4, characterized in that the second end of the pump barrel structure (31) is located between the first end of the plunger suspension barrel (421) and the second end of the plunger suspension barrel (421), the second end of the pump barrel structure (31) having an inward flange.

7. The submersible electric plunger pump of claim 6, characterized in that the inner diameter of the barrel structure (31) is clearance fit with the outer diameter of the first end of the plunger structure (42).

8. The submersible electric plunger pump according to claim 1, characterized in that the side of the first end of the traveling valve assembly (32) is provided with an oil inlet passage, the plunger structure (42) is a cylindrical structure, and the area of the oil inlet passage is larger than the sectional area of the plunger structure (42).

9. The submersible electric plunger pump according to claim 1, characterized in that the screen (21) has oil inlet passages on its side for communicating the inner space of the outer cylinder assembly (20) with the outer space of the outer cylinder assembly (20).

10. The submersible electric plunger pump according to any of the claims 1 to 9, characterized by further comprising a centralizer (60), the centralizer (60) being arranged on the motor stator (11) on the side of the motor stator (11) remote from the motor mover (12).