Inverted oil well pump

Abstract

The utility model provides an inverted oil well pump, and belongs to the technical field of oil well pumps. The inverted oil well pump comprises an outer pump cylinder, an inner pump cylinder and a plunger assembly which are sequentially nested from outside to inside, and further comprises a fixing valve located above the inner pump cylinder and the plunger assembly, the fixing valve is fixedly connected with the outer pump cylinder, a sand scraper is arranged at the upper end of the inner pump cylinder and comprises a sand scraping knife part, an elastic part and a fixed connecting part, and the sand scraping knife part is fixedly connected with the plunger assembly. The fixed connecting part is fixedly connected with the upper end of the inner pump cylinder, the elastic part is located between the sand scraping knife part and the fixed connecting part, the sand scraping knife part is attached to the outer peripheral wall of the plunger assembly, and a blade faces upwards so that fine silt on the outer peripheral wall of the pump cylinder assembly can be scraped away when the pump cylinder assembly moves downwards; and the fixed connecting part, the elastic part and the sand scraping knife part are arranged around the plunger assembly by one circle. According to the utility model, the sand scraper is arranged, so that settled fine silt is not easy to enter a gap between the plunger assembly and the inner pump cylinder, and the phenomenon of sand blockage is prevented.

Description

Technical Field

[0001] This utility model belongs to the field of oil pumps, and in particular relates to an inverted oil pump. Background Technology

[0002] Oil pumps are essential equipment in oilfield production, and their lifting methods include rod lifting and rodless lifting. For directional wells and horizontal wells with complex well trajectories, rod pumps are prone to problems such as tubing wear and breakage. In such cases, rodless submersible plunger pumps are more suitable.

[0003] Submersible plunger pumps utilize a linear motor below to drive lifting, eliminating the need for sucker rods and offering advantages such as high system efficiency, adaptability to large well inclinations, and a high degree of intelligence. A Chinese invention patent application with publication number CN10277363A, published on November 14, 2012, discloses an intelligent reversing electric submersible rodless pumping device. This device includes an inverted plunger pump, which is a type of submersible plunger pump. The inverted plunger pump includes a tubing coupling, an outer tube (i.e., an outer pump barrel), a pump barrel assembly, a plunger assembly, an inlet valve, a push rod, and an inlet coupling. The tubing coupling is connected to the upper end of the outer tube, and the inlet coupling is connected to the lower end of the outer tube. The pump barrel assembly includes an inner pump barrel fixed to the outer tube and a fixed valve connected to the upper end of the inner pump barrel. The plunger assembly is slidably and guidedly disposed in the inner pump barrel. The inlet valve is connected to the lower end of the plunger assembly, and the push rod is connected to the lower end of the inlet valve. The up-and-down movement of the push rod can drive the plunger assembly to move up and down.

[0004] The space enclosed by the upper end of the plunger assembly, the fixed valve, and the inner pump barrel is a cavity with variable volume. When the plunger assembly moves upward, the volume of this cavity decreases; when the plunger assembly moves downward, the volume of this cavity increases. The liquid in this cavity flows from bottom to top. During the flow, fine sand in the liquid easily deposits on the top of the plunger assembly. As the plunger assembly moves, this fine sand enters the gap between the plunger assembly and the inner pump barrel and easily adheres to the outer peripheral wall of the plunger assembly. When there is a lot of fine sand, it will wear down the surface of the plunger assembly and the inner pump barrel, resulting in poor sealing between the plunger assembly and the inner pump barrel and easy corrosion. In severe cases, it may even cause the oil pump to seize up. Utility Model Content

[0005] The purpose of this utility model is to provide an inverted oil pump to solve the technical problem in the prior art that fine sand can easily enter the gap between the plunger assembly and the inner pump barrel, causing wear and jamming of the plunger assembly and the inner pump barrel.

[0006] To achieve the above objectives, the technical solution of the inverted oil pump provided by this utility model is as follows:

[0007] An inverted oil pump includes an outer pump barrel, an inner pump barrel, and a plunger assembly nested from the outside to the inside. It also includes a fixed valve located above the inner pump barrel and the plunger assembly. The fixed valve is fixedly connected to the outer pump barrel. A scraper is provided at the upper end of the inner pump barrel. The scraper includes a scraping blade part, an elastic part, and a fixed connection part. The fixed connection part is fixedly connected to the upper end of the inner pump barrel. The elastic part is located between the scraping blade part and the fixed connection part. The scraping blade part is in contact with the outer peripheral wall of the plunger assembly and the blade is facing upward so as to scrape off the fine sand on the outer peripheral wall of the pump barrel assembly when the pump barrel assembly moves downward. The fixed connection part, the elastic part, and the scraping blade part are all arranged around the plunger assembly.

[0008] As a further improvement, an annular storage space is provided between the inner and outer pump cylinders and between the scraper and the outer pump cylinder to collect the scraped fine sand.

[0009] As a further improvement, the fixed connection part is formed with internal threads, and the upper end of the inner pump cylinder mates with the internal threads of the fixed connection part.

[0010] As a further improvement, the inner pump cylinder includes a main body and a connector portion located at the upper end of the main body. The outer diameter of the connector portion is smaller than the outer diameter of the main body, and the connector portion is formed with an external thread that mates with the fixed connection portion.

[0011] As a further improvement, the fixed connection part is ring-shaped, the elastic part is integrally connected to one axial end of the fixed connection part and is in a cantilever state of axial extension, at least two elastic parts are provided along the circumference of the fixed connection part, a slit is provided between two adjacent elastic parts in the circumference, and the scraping blade part is located at the end of the elastic part that is axially away from the fixed connection part.

[0012] As a further improvement, the outer peripheral wall of the scraper blade is provided with an outer conical surface for guiding fine sand to settle downwards.

[0013] As a further improvement, the scraper has a crack-stopping hole that communicates with the cut at one end of the cut near the fixed connection.

[0014] As a further improvement, the upper end of the outer pump barrel is fixedly connected to a pump barrel upper connector. The outer diameter of the upper end of the pump barrel upper connector is smaller than the outer diameter of the lower end of the pump barrel upper connector. The upper end of the pump barrel upper connector is provided with internal and external threads. The fixed valve is engaged with the internal thread of the upper end of the pump barrel upper connector. The oil pipe coupling used for connecting with the oil pipe is engaged with the external thread of the upper end of the pump barrel upper connector.

[0015] As a further improvement, the tubing coupling includes a coupling body and an adapter pipe that are threaded together, with the end of the adapter pipe away from the coupling body engaging with the external thread at the upper end of the connector on the pump barrel.

[0016] As a further improvement, at least one annular sand-collecting groove is provided on the outer peripheral wall of the plunger assembly.

[0017] The beneficial effects are as follows: The inverted oil pump provided by this utility model is an improvement on the existing technology. This utility model adds a scraper to the existing technology. The scraper acts as a shield above the gap between the inner pump barrel and the plunger assembly. The scraper utilizes the elastic force generated by the deformation of its elastic part to press the scraper blade tightly against the plunger assembly. This ensures a good fit between the scraper blade and the plunger assembly, preventing settled fine sand from easily entering the gap between the plunger assembly and the inner pump barrel. It also prevents excessive force between the scraper blade and the plunger assembly from affecting its normal movement. For fine sand adhering to the outer peripheral wall of the plunger assembly, the scraper can remove it as the plunger assembly moves downwards, thus preventing fine sand from being carried into the gap between the plunger assembly and the inner pump barrel. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of one embodiment of the inverted oil pump of this utility model;

[0019] Figure 2 This is a partial structural schematic diagram of one embodiment of the inverted oil pump of this utility model;

[0020] Figure 3 This is a schematic diagram of the scraper structure in one embodiment of the inverted oil pump of this utility model.

[0021] Explanation of reference numerals in the attached figures:

[0022] 1. Outer pump barrel; 2. Inner pump barrel; 21. Main body; 22. Connector; 3. Plunger barrel; 4. Upstream moving valve; 5. Downstream moving valve; 6. Push rod connector; 7. Push rod; 8. Upper connector of pump barrel; 9. Coupling body; 10. Adapter pipe; 11. Fixed valve; 12. Lower connector of pump barrel; 13. Lower end connector; 14. Scraper; 141. Fixed connection part; 142. Elastic part; 143. Scraper blade part; 144. Cutting slit; 145. Crack-stopping round hole; 15. Annular storage space; 16. Settling tank; 17. Inlet screen pipe. Detailed Implementation

[0023] The present invention will be further described in detail below with reference to the embodiments.

[0024] To address the problems in the prior art, the basic concept of this utility model is to install a scraper on the inner or outer pump cylinder for scraping fine sand from the outer peripheral wall of the plunger assembly, so that the settled fine sand is less likely to enter the gap between the plunger assembly and the inner pump cylinder, thus preventing sand jamming.

[0025] Specific embodiment 1 of the inverted oil pump provided by this utility model:

[0026] An inverted oil pump, see attached. Figure 1 It includes an outer pump barrel 1, an inner pump barrel 2 and a plunger assembly nested from the outside to the inside, and also includes a pump barrel upper connector 8, an oil pipe coupling, a fixed valve 11, a pump barrel lower connector 12, an inlet screen pipe 17, a lower end connector 13 and a sand scraper 14.

[0027] The upper end of the pump barrel lower connector 12 is formed with internal and external threads. The lower end of the outer pump barrel 1 is engaged with the external thread at the upper end of the pump barrel lower connector 12, and the lower end of the inner pump barrel 2 is engaged with the internal thread at the upper end of the pump barrel lower connector 12. The outer pump barrel 1 and the inner pump barrel 2 are fixedly connected through the pump barrel lower connector 12, and an annular space with a closed lower end and an open upper end is formed between the outer pump barrel 1 and the inner pump barrel 2.

[0028] The lower end of the pump barrel lower connector 12 is formed with an internal thread. The upper end of the inlet screen pipe 17 mates with the internal thread at the lower end of the pump barrel lower connector 12. The side wall of the inlet screen pipe 17 is provided with a screen hole running radially through it, which is used to initially filter out large solid particles in the liquid. The lower end of the inlet screen pipe 17 is connected to the lower end connector 13 by a thread, so as to facilitate connection with the reciprocating motion converter.

[0029] The upper end of the outer pump barrel 1 is provided with an internal thread. The upper connector 8 of the pump barrel 1 mates with the internal thread at the upper end of the outer pump barrel 1. The upper end of the upper connector 8 is formed with both internal and external threads. The fixed valve 11 mates with the internal thread at the upper end of the upper connector 8. The tubing coupling mates with the external thread at the upper end of the upper connector 8. The outer diameter of the upper end of the upper connector 8 is smaller than the outer diameter of the lower end of the upper connector 8, thereby ensuring that there is sufficient clearance between the tubing coupling and the well casing when the upper connector 8 is connected to the tubing coupling. Specifically, the tubing coupling includes a coupling body 9 and a connecting pipe 10. The lower end of the connecting pipe 10 mates with the external thread at the upper end of the upper connector 8, and the upper end of the connecting pipe 10 is provided with an external thread and threadedly connected to the coupling body 9. The connecting pipe 10 allows the coupling body and the fixed valve 11 to be offset vertically, avoiding interference when connecting the tubing.

[0030] The plunger assembly includes, from top to bottom, an upstream actuating valve 4, a plunger cylinder 3, a downstream actuating valve 5, a push rod connector 6, and a push rod 7. The upper end of the plunger cylinder 3 has an external thread, which mates with the external thread of the upstream actuating valve 4. The lower end of the plunger cylinder 3 has an internal thread, which mates with the internal thread of the downstream actuating valve 5. The lower end of the downstream actuating valve 5 has an internal thread, which mates with the internal thread of the lower end of the push rod connector 6. The lower end of the push rod connector 6 has an external thread, which mates with the external thread of the lower end of the push rod 7. A flow hole for liquid flow is provided on the push rod connector 6.

[0031] The scraper 14 is machined from a single piece of metal; see attached document. Figure 2 and attached Figure 3The pump cylinder 2 includes a fixed connecting part 141, an elastic part 142, and a scraping blade part 143. The fixed connecting part 141 is annular and has internal threads, and the upper end of the inner pump cylinder 2 mates with the internal threads of the fixed connecting part 141. The elastic part 142 is integrally connected to one axial end of the fixed connecting part 141 and is cantilevered. Multiple elastic parts 142 are provided and arranged circumferentially along the fixed connecting part 141. A slit 144 is provided between two adjacent circumferentially adjacent elastic parts 142 to facilitate radial elastic deformation of each elastic part 142. The scraping blade part 143 is located at the end of each elastic part 142 away from the fixed connecting part 141. Each scraping blade part 143 is arc-shaped to fit against the outer peripheral wall of the plunger cylinder 3, and the blade of the scraping blade part 143 faces upwards during use. The scraper 14 has a crack-prevention hole 145 at one end of the cut 144 near the fixed connection part 141 to avoid stress concentration and prevent the scraper 14 from cracking during use. The outer peripheral walls of the elastic part 142 and the scraper blade part 143 are both provided with an outer conical surface. On the one hand, this can reduce the thickness of the elastic part 142, making it easier for the elastic part 142 to deform elastically. On the other hand, the outer conical surface guides the scraped fine sand, making it easier for the fine sand to fall.

[0032] The plunger assembly has two movement processes: upward and downward. During the upward movement, the space between the upper end of the plunger assembly and the fixed valve 11 decreases, increasing the pressure within this space. Therefore, both the upstream moving valve 4 and the downstream moving valve 5 are closed, while the fixed valve 11 opens under pressure, allowing the liquid in this space to flow upward through the fixed valve 11. During the downward movement, the space between the upper end of the plunger assembly and the fixed valve 11 expands, decreasing the pressure within this space. The fixed valve 11 remains closed, while the upstream moving valve 4 and the downstream moving valve 5 open under pressure. Liquid below the inverted pump flows upward into the plunger cylinder 3, and liquid in the plunger cylinder 3 flows upward into the space between the upper end of the plunger assembly and the fixed valve 11. This process is repeated, continuously lifting the liquid in the well.

[0033] During the downward movement of the plunger assembly, the scraper blade 143 of the scraper 14 can scrape away fine sand from the outer peripheral wall of the plunger assembly, especially the outer peripheral wall of the plunger cylinder 3. Furthermore, the scraper 14 acts as a shield above the gap between the inner pump cylinder 2 and the plunger assembly, effectively preventing fine sand from entering the gap. The elastic part 142 of the scraper 14 allows the scraper blade 143 to fit tightly against the outer peripheral wall of the plunger assembly and maintain a certain clamping force. The elastic part 142 can undergo radial elastic deformation, thus ensuring that the clamping force is not too large and affects the normal up-and-down movement of the plunger assembly.

[0034] The fine sand scraped off by the plunger assembly will settle downwards into the annular space between the outer pump barrel 1 and the inner pump barrel 2 to prevent the fine sand from accumulating. This annular space constitutes an annular storage space 15 for collecting the fine sand. In order to ensure sufficient radial dimension of the annular storage space 15 and avoid the radial dimension of the annular storage space 15 decreasing after the installation of the scraper 14, in this embodiment, the inner pump barrel 2 includes a main body 21 and a connector 22 located at the upper end of the main body 21. The outer diameter of the connector 22 is smaller than the outer diameter of the main body 21. The connector 22 is formed with an external thread that mates with the fixed connection part 141. In this way, after the scraper 14 is installed, the distance between the outer peripheral wall of the scraper 14 and the inner peripheral wall of the outer pump barrel 1 can be larger.

[0035] In other embodiments, the tubing coupling may consist only of the coupling body, which is directly threaded to the upper end of the pump barrel connector. To avoid interference, in this embodiment, a radially inwardly protruding connecting ring is provided inside the outer pump barrel at a position lower than the tubing coupling. The inner circumferential wall of the connecting ring is formed with internal threads, and the fixing valve is threadedly engaged with the connecting ring. In this embodiment, the lower end of the tubing coupling may be provided with external threads for direct threaded connection to the upper end of the outer pump barrel, eliminating the need for a separate pump barrel connector.

[0036] In other embodiments, the scraper may not have a crack-stopping hole. This embodiment can improve the surface quality of the cut sidewall to achieve the purpose of crack prevention.

[0037] In other embodiments, an outer conical surface may be provided only in the scraper portion; or no outer conical surface may be provided in either the elastic portion or the scraper portion, in which case the outer diameters of the scraper portion and the elastic portion are equal.

[0038] In other embodiments, the elastic part can be fixedly connected to the fixed connection part by welding.

[0039] In other embodiments, the scraper may include multiple parts, each part including a fixed connection part, an elastic part and a scraping blade part. In this embodiment, the parts are spliced ​​together circumferentially to form a ring-shaped scraper. In this embodiment, the fixed connection part can be fixedly connected to the upper end of the inner pump cylinder by welding or bolting.

[0040] In applications where the amount of fine sand deposited is small, an annular storage space is not required. In this case, the fixed connection part of the scraper can be fitted with the inner circumferential wall of the outer pump cylinder, or the inner pump cylinder can be fitted with the inner circumferential wall of the outer pump cylinder.

[0041] Specific embodiment 2 of the inverted oil pump provided by this utility model:

[0042] This embodiment is based on Embodiment 1. The difference between this embodiment and Embodiment 1 is that the fixed connection part of the scraper is fixedly connected to the upper wall of the inner pump cylinder by welding. Since the fixed connection part is no longer sleeved outside the inner pump cylinder, the upper end of the inner pump cylinder does not need to be provided with a joint part.

[0043] Specific embodiment 3 of the inverted oil pump provided by this utility model:

[0044] This embodiment is based on Embodiment 1, and the difference between it and Embodiment 1 is as follows: see Appendix Figure 2 In this embodiment, the outer wall of the plunger cylinder 3 is machined with multiple annular sand settling grooves 16. The sand particles that have entered the gap between the plunger assembly and the inner pump cylinder 2 will roll as the plunger assembly moves up and down. When these sand particles roll to the sand settling grooves 16, they will be deposited in the sand settling grooves 16, preventing the sand particles from continuing to roll between the plunger assembly and the inner pump cylinder 2 and causing wear on the plunger assembly and the inner pump cylinder 2.

[0045] The number of sedimentation tanks 16 can be selected as needed; one or two tanks can be set, or multiple tanks can be set as required.

[0046] Finally, it should be noted that the above description is only a preferred embodiment of this utility model and is not intended to limit this utility model. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still make modifications to the technical solutions described in the foregoing embodiments without creative effort, or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. An inverted oil pump, comprising an outer pump barrel, an inner pump barrel, and a plunger assembly nested sequentially from the outside to the inside, and further comprising a fixed valve located above the inner pump barrel and the plunger assembly, characterized in that, The fixed valve is fixedly connected to the outer pump cylinder. A scraper is provided at the upper end of the inner pump cylinder. The scraper includes a scraping blade part, an elastic part, and a fixed connection part. The fixed connection part is fixedly connected to the upper end of the inner pump cylinder. The elastic part is located between the scraping blade part and the fixed connection part. The scraping blade part is in contact with the outer peripheral wall of the plunger assembly and the blade is facing upward so as to scrape off the fine sand on the outer peripheral wall of the pump cylinder assembly when the pump cylinder assembly moves downward. The fixed connection part, the elastic part, and the scraping blade part are all arranged around the plunger assembly.

2. The inverted oil pump according to claim 1, characterized in that, An annular storage space is provided between the inner pump cylinder and the outer pump cylinder, and between the scraper and the outer pump cylinder, to collect the scraped fine sand.

3. The inverted oil pump according to claim 2, characterized in that, The fixed connection part is formed with internal threads, and the upper end of the inner pump cylinder is engaged with the internal threads of the fixed connection part.

4. The inverted oil pump according to claim 3, characterized in that, The inner pump cylinder includes a main body and a connector portion located at the upper end of the main body. The outer diameter of the connector portion is smaller than the outer diameter of the main body, and the connector portion is formed with external threads that mate with the fixed connection portion.

5. The inverted oil pump according to any one of claims 1-4, characterized in that, The fixed connection part is ring-shaped, and the elastic part is integrally connected to one axial end of the fixed connection part and is in a cantilever state extending axially. At least two elastic parts are provided along the circumference of the fixed connection part, and a slit is provided between two adjacent elastic parts in the circumference. The scraping blade part is located at the end of the elastic part that is axially away from the fixed connection part.

6. The inverted oil pump according to claim 5, characterized in that, The outer peripheral wall of the scraper blade is provided with an outer conical surface for guiding fine sand to settle downwards.

7. The inverted oil pump according to claim 5, characterized in that, The scraper has a crack-stopping hole at one end of the cut near the fixed connection, which communicates with the cut.

8. The inverted oil pump according to any one of claims 1-4, characterized in that, The upper end of the outer pump barrel is fixedly connected to the upper pump barrel connector. The outer diameter of the upper end of the upper pump barrel connector is smaller than the outer diameter of the lower end of the upper pump barrel connector. The upper end of the upper pump barrel connector is provided with internal and external threads. The fixed valve is engaged with the internal thread of the upper end of the upper pump barrel connector. The oil pipe coupling used for connecting with the oil pipe is engaged with the external thread of the upper end of the upper pump barrel connector.

9. The inverted oil pump according to claim 8, characterized in that, The tubing coupling includes a coupling body and an adapter pipe that are threaded together. The end of the adapter pipe away from the coupling body is engaged with the external thread at the upper end of the connector on the pump barrel.

10. The inverted oil pump according to any one of claims 1-4, characterized in that, At least one annular sand settling groove is provided on the outer peripheral wall of the plunger assembly.

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