An oil production system with upper motor and lower pump

Abstract

The present invention discloses an oil production system with an upper motor and a lower pump, comprising a submersible linear motor and a plunger pump, wherein the submersible linear motor and the plunger pump form an annular structure, and a cable is arranged inside the submersible linear motor; the submersible linear motor comprises a stator and a mover sleeved on the inner side of the stator; the oil production system further comprises an outer interlayer of an outer cylinder and an inner interlayer of an outer cylinder, wherein the inner interlayer of the outer cylinder is fixed at the upper and lower joints of the stator, and the outer interlayer of the outer cylinder is arranged at the outermost side of the submersible linear motor; an annular cavity is formed between the outer interlayer of the outer cylinder and the inner interlayer of the outer cylinder, and the inner and outer interlayers of the outer cylinder are oiled, so that the stator and the mover are both immersed in the oil. The present invention can be used in conjunction with the cable and a variety of air and sand prevention measures can be added after the pump, and the oiling of the outer cylinder interlayer makes the stator and the mover both immersed in the flowing oil, and the heat dissipation effect is significantly increased.

Description

Technical Field

[0001] The invention belongs to the technical field of oil production equipment, and in particular, relates to an oil production system with an upper motor and a lower pump. Background Art

[0002] The submersible linear motor systems currently used in rodless oil production mostly have the pump on top and the motor on the bottom, and use the linear reciprocating motion of the linear motor to drive the pumping rod up and down to lift the crude oil in the well. Since the linear induction motor runs in the narrow space underground for a long time, a large amount of heat is generated, which can easily burn the motor. Moreover, when this system structure is used for oil production, it is difficult to hang the suspended sand filter pipe of the oil field for a long time at the back, and the dust and sand prevention measures are less effective. Most of the existing submersible linear motor rodless oil production systems have an upper pump and a lower motor, or an upper motor and a lower pump with oil passing through the movable shaft. The upper pump and lower motor type motor is difficult to cooperate with the internal cable, and the upper motor and the lower pump with oil passing through the movable shaft of the motor. At this time, the strength and rigidity of the movable shaft are difficult to guarantee, which can easily cause the movable shaft to be deformed and deformed.

[0003] Rod pump lifting is still the most mature oil production equipment in oil fields, but it is affected by many factors and has serious eccentric wear. The reciprocating submersible linear electric pump belongs to the category of rodless pump lifting technology. The system usually includes a ground control cabinet, cables, submersible linear motors, plunger pumps, etc., and its working principle is mostly that the ground 380V voltage is boosted to the rated working voltage of the submersible linear motor, and transmitted to the submersible linear motor at the bottom through the cable (some sensors are also installed at the bottom of the submersible linear motor). The mover of the submersible linear motor is connected to the plunger of the plunger pump. The submersible linear motor reciprocates under the action of alternating current, cutting the magnetic flux lines, thereby driving the plunger pump to reciprocate. However, since the pump is at the bottom of the entire pipe string, it is affected by the valve ball and valve seat, and it is difficult to implement internal cable applications.

[0004] The existing patent publication number CN114075948A discloses an inverted electric submersible piston pump and a submersible linear motor, wherein the inverted electric submersible piston pump includes an upper pump plunger, an upper pump barrel and a submersible linear motor which are sequentially sleeved from the inside to the outside, the lower end of the lower pump barrel is connected to a lower pump fixed valve assembly, the lower end of the upper pump plunger is connected to an upper pump fixed valve assembly, the lower end of the upper pump barrel is connected to an upper pump floating valve assembly, the lower end of the upper pump barrel is connected to a lower pump plunger, and the lower end of the lower pump plunger is fixedly connected to a lower pump floating valve assembly. The inverted electric submersible piston pump adopts a structure in which the motor is connected to the piston pump at the top and bottom, which can cooperate with the later internal cable research and development to realize the internal cable + electric submersible piston pump structure. Although this patent also adopts the structure of upper motor and lower pump, the pumped oil is only pumped to the ground through the hollow rotor shaft, and the oil does not pass through the stator, which can easily cause the stator to overheat; at the same time, the strength and rigidity of the rotor shaft are difficult to guarantee, which can easily cause the rotor shaft to have large deflection and deformation, and be easy to deform. Summary of the invention

[0005] The present invention is mainly aimed at the problem that in the prior art, most of the rodless oil production systems of submersible linear motors are upper pump and lower motor, or upper motor and lower pump with oil passing through the movable shaft. The upper pump and lower motor type motor is difficult to match with the cable, and the upper motor and lower pump with oil passing through the movable shaft of the motor is difficult to ensure the strength and rigidity of the movable shaft, which easily causes the movable shaft to have large deflection and deformation. An oil production system with upper motor and lower pump is disclosed.

[0006] In view of the above technical problems, the technical solutions of the present invention are as follows:

[0007] An oil production system with an upper motor and a lower pump comprises a submersible linear motor and a plunger pump, wherein the submersible linear motor and the plunger pump form an annular structure, and a cable is arranged inside the submersible linear motor; the submersible linear motor comprises a stator and a mover sleeved on the inner side of the stator; the oil production system further comprises an outer interlayer of an outer cylinder and an inner interlayer of an outer cylinder, wherein the inner interlayer of the outer cylinder is fixed at the upper and lower joints of the stator, and the outer interlayer of the outer cylinder is arranged at the outermost side of the submersible linear motor; an annular cavity is formed between the outer interlayer of the outer cylinder and the inner interlayer of the outer cylinder, and the inner and outer interlayers of the outer cylinder are oiled so that the stator and the mover are both immersed in oil.

[0008] Furthermore, it also includes an upper coupling, an upper connecting pipe and a centralizer, wherein the centralizer is arranged on the inner side of the upper joint of the stator and the inner side of the lower joint of the stator, and one side of the centralizer presses the magnetic steel and the magnetic pole.

[0009] Furthermore, the upper coupling is used to connect the motor and the oil pipe, and the upper coupling is connected to the stator through an upper connecting pipe.

[0010] Furthermore, the mover includes a mover shaft, a mover upper joint, a mover lower joint, a plurality of magnets and magnetic poles. The mover upper joint locks the magnet on the mover shaft. A permanent magnet is fixedly connected between the magnet and the magnetic pole. The magnet, permanent magnet and magnetic pole are alternately arranged in sequence along the axis direction of the mover shaft.

[0011] Furthermore, the stator comprises a stator upper joint, a stator inner tube and a stator lower joint, an electromagnetic magnetic gap is formed between the stator inner tube and the mover, and the stator upper joint connects the stator with the upper connecting pipe and the inner layer of the outer tube.

[0012] Furthermore, it also includes reinforcing ribs, which are fixed at the outer wall of the outer interlayer of the outer tube at intervals in the axial direction to connect the outer interlayer of the outer tube with the inner interlayer of the outer tube.

[0013] Furthermore, the reinforcing rib is a circular ring structure, and a plurality of pairs of holes are evenly arranged on the reinforcing rib.

[0014] Furthermore, the reinforcing ribs are of a multi-petal structure and are evenly distributed in the radial direction, and the length of the reinforcing ribs in the axial direction is smaller than the axial length of the inner interlayer of the outer tube.

[0015] Furthermore, the plunger pump includes a plunger, a plunger coupling, a pump body, a floating valve and a fixed valve installed at one end of the pump body. The plunger pump is arranged at the lower end of the submersible linear motor, the plunger is connected to the mover through the plunger coupling, and the pump body is connected to the submersible linear motor through a lower connecting pipe; the floating valve is connected to the oil pressure chamber of the plunger pump through a pipeline.

[0016] Furthermore, the plunger pump also includes a sealing ring and a packing seal, which are used to seal the gap between the plunger and the pump body and between the plunger and the lower connecting pipe.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] 1. The present invention includes a submersible linear motor and a plunger pump, the submersible linear motor and the plunger pump form an annular structure, and a cable is arranged inside the submersible linear motor; the submersible linear motor includes a stator and a mover sleeved on the inner side of the stator; the oil production system also includes an outer interlayer of an outer tube and an inner interlayer of an outer tube, the inner interlayer of the outer tube is fixed at the upper and lower joints of the stator, and the outer interlayer of the outer tube is arranged at the outermost side of the submersible linear motor; an annular cavity is formed between the outer interlayer of the outer tube and the inner interlayer of the outer tube, and the inner and outer interlayers of the outer tube are oiled, so that the stator and the mover are immersed in the oil. The inner and outer interlayers of the outer tube are oiled so that the stator and the mover of the submersible linear motor are immersed in the flowing oil, which can effectively increase the heat dissipation effect and prevent the submersible linear motor from being damaged by overheating.

[0019] 2. The present invention is an upper motor and lower plunger pump structure, which is suitable for various downhole environments, is equipped with cables inside, and various air and sand prevention equipment can be added after the pump; the upper motor and lower pump with the motor mover shaft oiled has high strength and rigidity of the mover shaft, which can ensure that the mover shaft is not easily deformed. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0021] Figure 2 It is an enlarged schematic diagram of the upper structure of the present invention;

[0022] Figure 3 It is an enlarged schematic diagram of the middle part structure of the present invention;

[0023] Figure 4 It is an enlarged schematic diagram of the lower structure of the present invention;

[0024] Figure 5 It is a schematic diagram of the reinforcing rib structure of the present invention;

[0025] Figure 6 Another structural schematic diagram of the reinforcing rib of the present invention;

[0026] Figure 7Another schematic diagram of installing the reinforcing rib of the present invention on a motor.

[0027] In the above figure, 1. upper coupling; 2. cable; 3. upper connecting pipe; 4. outer interlayer of outer cylinder; 5. upper joint of mover; 6. mover shaft; 7. magnet; 8. magnetic pole; 9. centralizer; 10. upper joint of stator; 11. stator end cover; 12. electromagnetic magnetic gap; 13. stator inner cylinder; 14. stator coil; 15. stator core; 16. reinforcing rib; 17. lower joint of stator; 18. lower joint of mover; 19. plunger coupling; 20. plunger; 21. lower connecting pipe; 22. packing seal; 23. pump body; 24. floating valve; 25. oil pressure chamber; 26. sealing ring; 27. oil suction chamber; 28. fixed valve; 29. ​​inner interlayer of outer cylinder; 30. cavities of inner and outer interlayers of outer cylinder; 31. cavity. DETAILED DESCRIPTION

[0028] In order to clearly illustrate the technical features of the application scheme of the present invention, the present invention is described in detail below through specific implementation methods and in conjunction with the accompanying drawings.

[0029] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited to the specific embodiments disclosed below.

[0030] In addition, in the description of the present invention, it should be understood that the terms "center", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first" and "second" are used only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0031] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or a communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0032] In the present invention, unless otherwise clearly specified and limited, the first feature "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. In the description of this specification, reference terms; descriptions of "one embodiment", "some embodiments", "examples", "specific examples" or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in an appropriate manner in any one or more embodiments or examples.

[0033] Example 1

[0034] like Figure 1 As shown, an oil production system with an upper motor and a lower pump comprises a submersible linear motor and a plunger pump, wherein the submersible linear motor and the plunger pump form an annular structure, and a cable 2 is arranged inside the submersible linear motor; the submersible linear motor comprises a stator and a mover sleeved on the inner side of the stator; the oil production system further comprises an outer tube outer layer 4 and an outer tube inner layer 29, wherein the outer tube inner layer 29 is fixed at the upper and lower joints of the stator, and the outer tube outer layer 4 is arranged at the outermost side of the submersible linear motor; an annular cavity is formed between the outer tube outer layer 4 and the outer tube inner layer 29, and the inner and outer layers of the outer tube are oiled, so that the stator and the mover are both immersed in oil, which significantly increases the heat dissipation effect inside the motor, effectively avoids overheating of the motor, and helps to improve the operating stability and life of the motor; in harsh environments such as oil well production, the outer tube interlayer oiling design can more effectively cope with these environmental challenges and ensure that the motor can operate stably under harsh conditions.

[0035] like Figure 2As shown, in this embodiment, the mover includes a mover shaft 6, a mover upper joint 10, a mover lower joint 18, a plurality of magnets 7 and magnetic poles 8. The mover upper joint 6 locks the magnet 7 on the mover shaft 6. A permanent magnet is fixedly connected between the magnet 7 and the magnetic pole 8. The magnet 7, the permanent magnet and the magnetic pole 8 are alternately arranged in sequence along the axial direction of the mover shaft 6 to form a magnetic field, and interact with the magnetic field in the stator to generate a driving force; wherein the magnet 7, the permanent magnet and the magnetic pole 8 are all annular structures, which help to enhance the uniformity and stability of the magnetic field.

[0036] The upper joint 5 of the mover and the lower joint 18 of the mover are respectively arranged at the upper end and the lower end of the submersible linear motor, which not only play the role of connection and fixing, but also are responsible for connecting the mover with other components (such as stator, plunger pump, etc.). The upper joint 5 of the mover is specially designed with a locking mechanism for firmly locking the magnetic steel 7 on the mover shaft 6.

[0037] like Figure 2 and Figure 3 As shown, the stator is composed of a stator upper joint 10, a stator inner tube 13 and a stator lower joint 17. An electromagnetic magnetic gap is formed between the stator inner tube 13 and the mover; the stator also includes a stator coil 14, a stator end cover 11 and a stator core 15. The stator end cover 11 is arranged at the lower end of the stator upper joint 10, which plays a role in sealing and protecting the internal structure of the stator, and also helps the heat dissipation and insulation of the stator. The stator coil 14 and the stator core 15 are arranged alternately. The stator coil 14 is a key component for generating a magnetic field. It is usually made of copper wire wrapped with multiple layers of insulating film to ensure good insulation performance; the stator core 15 is used for magnetic conduction and support of the stator coil 14. They are arranged alternately on the stator inner tube 13 to form a stable magnetic field structure. The stator upper joint 10 fixes the stator to the upper connecting pipe 3 and the inner interlayer 29 of the outer tube.

[0038] The present invention also includes an upper coupling 1, an upper connecting pipe 3 and a centralizer 9. The centralizer 9 is arranged on the inner side of the stator upper joint 10 and the inner side of the stator lower joint 17. One side of the centralizer 9 presses the magnetic steel 7 and the magnetic pole 8. The upper coupling 1 is used to connect the motor and the oil pipe. The upper coupling 1 is connected to the stator through the upper connecting pipe 3.

[0039] The power device of the reciprocating submersible electric pump is a submersible linear motor, which is a cylindrical linear motor. The mover is located at the center of the cylinder and reciprocates along the axial direction of the cylinder. The stator is annular and is sleeved on the mover. The working principle of the present invention is: when electric energy is transmitted to the submersible linear motor, a magnetic field will be generated inside the stator of the motor. This magnetic field interacts with the mover of the motor to generate electromagnetic thrust; this electromagnetic thrust will drive the plunger pump to rotate. Under the action of the plunger pump, the well fluid (including oil and gas) is sucked into the pump. When the plunger 20 moves downward, the oil flows through the mover and stator, and its pressure gradually increases, and is finally transported to the ground through the oil pipe.

[0040] Example 2

[0041] like Figure 3 As shown, in this embodiment, the plunger pump includes a plunger 20, a plunger coupling 19, a pump body 23, a floating valve 24, and a fixed valve 28 installed at one end of the pump body 23. The plunger pump is arranged at the lower end of the submersible linear motor. The plunger 20 is connected to the mover through the plunger coupling 19 to ensure that the plunger 20 can move accurately with the movement of the mover. The pump body 23 is the outer shell of the plunger pump, and a chamber is provided inside to accommodate the plunger and the valve. At the same time, it is connected to the lower connecting pipe 21 to fix the plunger pump to the lower end of the submersible linear motor. The floating valve 24 is connected to the oil pressure chamber 25 of the plunger pump through a pipeline, and cooperates with the fixed valve 28 to achieve the suction and discharge of oil. The plunger pump also includes a sealing ring 26 and a packing seal 22, which are used to seal the gap between the plunger 20 and the pump body 23 and the plunger 20 and the lower connecting pipe 21.

[0042] The function of the plunger pump is mainly to utilize the reciprocating motion of the plunger 20. When the plunger 20 moves upward, the floating valve 24 is closed, the fixed valve 28 is opened, and the oil is sucked into the pump body 23. When the plunger 20 moves downward, the floating valve 24 is opened, the fixed valve 28 is closed, and the volume of the oil pressure chamber 25 increases, so that the pressure difference between the cavity 31 and the oil suction chamber 27 increases, and the floating valve 24 moves upward, so that the oil passes from the oil suction chamber 27 through the oil pressure chamber 25 and then enters the inner and outer interlayer cavities 30 of the outer cylinder, thereby immersing both the mover and the stator in the flowing oil, significantly improving the heat dissipation effect. The sealing ring 26 and the packing seal 22 ensure the sealing performance of the pump during operation, improving the working efficiency and reliability of the pump.

[0043] In this embodiment, a variety of air and sand prevention equipment can be added after the plunger pump, such as an exhaust separator assembly and a solid-liquid separation assembly, to improve the exhaust and sand prevention properties of the pump and increase the service life of the plunger pump.

[0044] Example 3

[0045] like Figure 4 , Figure 5 as well as Figure 6 As shown, in this embodiment, the reinforcing ribs 16 are welded and fixed to the outer wall of the outer tube outer interlayer 4 at intervals in the axial direction, connecting the outer tube outer interlayer 4 and the outer tube inner interlayer 29, and enhancing the overall strength and rigidity. The reinforcing ribs 16 are annular structures, and a plurality of pairs of circular holes are evenly arranged on the reinforcing ribs 16. The annular structure enables the reinforcing ribs 16 to evenly bear and disperse external forces, avoiding the occurrence of stress concentration, thereby extending the service life of the outer tube.

[0046] The reinforcing ribs 16 can also be configured as a multi-petal structure, evenly distributed in the radial direction, and the length of the reinforcing ribs 16 in the axial direction is less than the axial length of the inner interlayer 29 of the outer tube. Figure 6As shown, the reinforcing rib 16 is a three-petal structure, which is welded to the outer wall of the outer tube inner interlayer 29 at every other angle in the radial direction, and serves to connect the outer tube outer interlayer 4 and the outer tube inner interlayer 29, thereby enhancing the overall strength and rigidity. Figure 6 The arc angle of the reinforcing rib 16 in the embodiment is 60°, and one is welded radially every 60°. Holes can also be drilled on the reinforcing rib 16. Figure 7 As shown, the reinforcing rib 16 with an arc angle of 60° is installed between the inner and outer layers of the outer tube along the axial direction.

[0047] In this embodiment, the structure of the reinforcing rib 16 can be various structures, such as Figure 5 and Figure 6 Two of the listed Figure 5 The number and shape of the holes can be changed to other shapes, such as square or circle. Figure 6 The arc angles can be of various angles, and the interval angles between them are not fixed.

[0048] Obviously, the above-described embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the claims of the present invention.

Claims

1. An oil production system with an upper motor and a lower pump, comprising a submersible linear motor and a plunger pump, characterized in that: The submersible linear motor and the plunger pump form an annular structure, and a cable is arranged inside the submersible linear motor; the submersible linear motor includes a stator and a mover mounted on the inner side of the stator; the oil production system also includes an outer interlayer of an outer cylinder and an inner interlayer of an outer cylinder, the inner interlayer of the outer cylinder is fixed at the upper and lower joints of the stator, and the outer interlayer of the outer cylinder is arranged at the outermost side of the submersible linear motor; an annular cavity is formed between the outer interlayer of the outer cylinder and the inner interlayer of the outer cylinder, and the inner and outer interlayers of the outer cylinder are oiled, so that the stator and the mover are both immersed in oil.

2. The oil production system with upper motor and lower pump according to claim 1, characterized in that: It also includes an upper coupling, an upper connecting pipe and a centralizer. The centralizer is arranged on the inner side of the upper joint of the stator and the inner side of the lower joint of the stator. One side of the centralizer presses the magnetic steel and the magnetic pole.

3. The oil production system with upper motor and lower pump according to claim 2, characterized in that: The upper coupling is used to connect the motor and the oil pipe, and the upper coupling is connected to the stator through an upper connecting pipe.

4. The oil production system with upper motor and lower pump according to claim 1, characterized in that: The mover includes a mover shaft, a mover upper joint, a mover lower joint, a plurality of magnets and magnetic poles. The mover upper joint locks the magnet on the mover shaft. A permanent magnet is fixedly connected between the magnet and the magnetic pole. The magnet, permanent magnet and magnetic pole are alternately arranged in sequence along the axis direction of the mover shaft.

5. The oil production system with upper motor and lower pump according to claim 1, characterized in that: The stator comprises a stator upper joint, a stator inner tube and a stator lower joint. An electromagnetic magnetic gap is formed between the stator inner tube and the mover. The stator upper joint connects the stator with the upper connecting pipe and the inner layer of the outer tube.

6. The oil production system with upper motor and lower pump according to claim 1, characterized in that: It also includes reinforcing ribs, which are fixed at the outer wall of the outer interlayer of the outer cylinder at intervals in the axial direction to connect the outer interlayer of the outer cylinder with the inner interlayer of the outer cylinder.

7. The oil production system with upper motor and lower pump according to claim 6, characterized in that: The reinforcing rib is a circular ring structure, and a plurality of pairs of holes are evenly arranged on the reinforcing rib.

8. The oil production system with upper motor and lower pump according to claim 6, characterized in that: The reinforcing ribs are of a multi-petal structure and are evenly distributed in the radial direction. The length of the reinforcing ribs in the axial direction is smaller than the axial length of the inner interlayer of the outer tube.

9. The oil production system with upper motor and lower pump according to claim 1, characterized in that: The plunger pump includes a plunger, a plunger coupling, a pump body, a floating valve and a fixed valve installed at one end of the pump body. The plunger pump is arranged at the lower end of the submersible linear motor, the plunger is connected to the mover through the plunger coupling, and the pump body is connected to the submersible linear motor through a lower connecting pipe; the floating valve is connected to the oil pressure chamber of the plunger pump through a pipeline.

10. The oil production system with upper motor and lower pump according to claim 9, characterized in that: The plunger pump also includes a sealing ring and a packing seal, which are used to seal the gap between the plunger and the pump body and the gap between the plunger and the lower connecting pipe.

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