Sand scraping oil well pump and using method and assembling method thereof

Abstract

The invention discloses a sand scraping oil well pump and a using method and an assembling method thereof, the sand scraping oil well pump comprises a plunger and a pump cylinder, the plunger is arranged in the pump cylinder, and the sand scraping oil well pump further comprises a sand scraping ring; a lubricating hole is formed in the outer wall of the plunger, and a liquid separation mechanism is arranged in the plunger. At least one sand scraping groove is formed in the outer wall of the plunger, and a sand scraping ring is embedded in each sand scraping groove. An upper connector is arranged at the upper end of the plunger, a liquid outlet is formed in the upper connector, a drain valve is arranged at the lower end of the plunger, and a liquid inlet valve is arranged at the lower end of the pump cylinder; the inner wall of the lower end of the upper connector is connected with an inner pipe, the inner pipe is shorter than the plunger, and the inner pipe is provided with an inner pipe hole below the lubricating hole; the inner pipe hole can be formed in the side wall of the inner pipe or the bottom of the inner pipe. Zero-clearance sand scraping is achieved, and the problem that the plunger is clamped by sand is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of oil equipment, and specifically relates to a sand scraping oil extraction pump, its usage method, and its assembly method. Background Art

[0002] With the in-depth development of oilfield exploitation, low-permeability reservoirs and fault-block reservoirs begin to produce sand. When the oil extraction pump works in such sand-containing oil wells, it often fails due to sand jamming the plunger and the valve group getting stuck. The currently commonly used anti-jamming method is to use a long plunger anti-sand jamming pump. However, the conventional long plunger anti-sand jamming pump is mainly suitable for larger sand grains and is not suitable for low-permeability and fault-block reservoirs. The main reason is that the sand grains in these reservoirs are small in particle size, easy to enter the gap, which reduces the clearance between the plunger and the pump barrel, increases the frictional resistance, and the sand grains are also easy to jam the pump.

[0003] Publication (Announcement) No.: CN113217362B discloses a sand and gas prevention oil extraction pump, which includes a pump barrel assembly. A sliding plunger assembly is arranged in the pump barrel assembly. An air-liquid separation assembly is arranged at the end of the pump barrel assembly. An inlet liquid channel is arranged on one side of the air-liquid separation assembly. The sand-containing and gas-containing oil liquid is introduced into the pump barrel assembly through the inlet liquid channel. The short plunger in the plunger assembly abuts and slides in a sealed manner inside the pump barrel assembly to form a compression cavity for multi-stage sand settlement and gas exhaust. It adopts a three-stage sand prevention and two-stage gas prevention structure, which can not only adapt to the crude oil exploitation in well conditions with serious sand production, but also has a good gas prevention effect. It belongs to a special oil extraction pump that can adapt to the crude oil exploitation in well conditions with serious sand production, high gas content ratio, good sand and gas prevention effect, strong bearing capacity, and long service life.

[0004] The existing technology's sand anti-jamming method is a sand blocking and sand settlement method. However, due to its structural reasons, in order to effectively settle sand grains, the volume of the annular sand settlement cavity for the sand prevention measures of the plunger and the traveling valve is small, and the pipe string above the pump barrel is long, which cannot meet the long-term sand settlement requirements.

[0005] Publication (Announcement) No.: CN217950639U discloses a fixed-valve-free sand prevention oil extraction pump, which includes an outer pipe. An upper thin pump barrel and a lower thick pump barrel are installed inside the outer pipe. A mechanical seat seal is connected between the upper thin pump barrel and the lower thick pump barrel. The mechanical seat seal is detachably clamped on the outer pipe. An upper piston with a hollow interior is installed inside the upper thin pump barrel. A lower piston with a hollow interior is installed inside the lower thick pump barrel. An upstream traveling valve assembly is installed at the top end of the upper piston. The bottom end of the upper piston extends into the lower thick pump barrel and a sealing ring cavity is formed between them. The sealing ring cavity is communicated with the interior of the upper piston. A downstream traveling valve assembly one is connected between the upper piston and the lower piston. The bottom end of the lower piston is connected with a downstream traveling valve assembly two; this patent adopts a fixed-valve-free structure and relies on the change in the volume of the sealing ring cavity to realize the opening and closing process of the valve ball, solves problems such as sand burying and jamming the pump and gas locking, extends the service life, and improves the pump efficiency; and when checking the pump, it is no longer necessary to lift the tubing, saving the cost of checking the pump.

[0006] The existing sand control and sand sticking prevention method adopts a replacement idea. By removing the fixed valve, problems with the fixed valve can be avoided. However, to solve the problem of sand sticking the plunger, there is also a problem of wear and failure due to the swing of the locking mechanism.

[0007] Publication (Announcement) Number: CN111997878B discloses a sand - discharging oil extraction pump. The sand - discharging oil extraction pump includes an outer connecting pipe, a traveling valve assembly, a fixed valve assembly, a sand settling cylinder, and a sand - filtering pipe. The outer connecting pipe is connected to the production tubing, the traveling valve assembly is connected to the sucker rod. The traveling valve assembly and the fixed valve assembly are located inside the outer connecting pipe. The lower part of the traveling valve assembly is located inside the fixed valve assembly. A first diversion cavity is formed inside the fixed valve assembly. A first fixed valve and a second fixed valve are provided at the lower part of the fixed valve assembly. A second diversion cavity is formed between the fixed valve assembly and the outer connecting pipe. A sand - containing cavity is formed inside the sand settling cylinder, and the sand - containing cavity is communicated with the second diversion cavity. The sand - filtering pipe is connected to the outer connecting pipe, and filter holes are opened on the pipe wall of the sand - filtering pipe. When the first fixed valve is opened, the inside of the sand - filtering pipe is communicated with the first diversion cavity; when the second fixed valve is opened, the first diversion cavity is communicated with the second diversion cavity. This invention solves the technical problems that fine sand produced in the formation in the later stage of development is likely to cause blockage of the pump barrel and the production tubing string, and is likely to damage the oil extraction pump.

[0008] The existing sand control and sand sticking prevention method is based on the principle of sand blocking and sand settling, but it does not achieve gap sand control and scale prevention between the plunger and the pump barrel.

[0009] In summary, the technical solutions, the technical problems to be solved, and the beneficial effects of the above - disclosed technologies are all different from those of the present invention. For more technical features, technical problems to be solved, and beneficial effects of the present invention, there is no technical inspiration in the above - disclosed technical documents. Summary of the Invention

[0010] Aiming at the above - mentioned defects existing in the prior art, the purpose of the present invention is to provide a sand - scraping oil extraction pump, its use method, and its assembly method. There is no - gap dynamic sealing between the plunger and the pump barrel of the oil extraction pump, which can scrape and carry sand and scale, and take them away with the liquid flow, prevent sand and scale from getting stuck, and achieve long - life lifting of the oil extraction pump.

[0011] To achieve the above - mentioned purpose, the present invention adopts the following technical solutions:

[0012] A sand - scraping oil extraction pump includes a plunger and a pump barrel. The plunger is arranged in the pump barrel, and also includes a sand - scraping ring; lubricating holes are arranged on the outer wall of the plunger, and a liquid separation mechanism is arranged inside the plunger; at least one sand - scraping groove is arranged on the outer wall of the plunger, and a sand - scraping ring is embedded in each sand - scraping groove.

[0013] Furthermore, an upper joint is arranged at the upper end of the plunger, a liquid outlet is arranged on the upper joint, a drain valve is arranged at the lower end of the plunger, and a suction valve is arranged at the lower end of the pump barrel;

[0014] Specifically, the liquid separation mechanism is an inner tube; the inner wall of the lower end of the upper joint is connected to the inner tube, the inner tube is shorter than the length of the plunger, and the inner tube is provided with an inner tube hole below the lubricating hole;

[0015] Specifically, the inner tube hole can be arranged on the side wall or the bottom of the inner tube.

[0016] Further, when the sand scraping ring and the sand scraping groove are one, they are arranged above the lubricating hole.

[0017] Further, when the sand scraping ring and the sand scraping groove are at least two, they are distributed above and below the lubricating hole.

[0018] Further, the free outer diameter of the sand scraping ring is larger than the inner diameter of the pump barrel, and the sand scraping ring and the pump barrel are in an elastic interference fit.

[0019] Further, the sand scraping ring is composed of at least two anti-corrosion and wear-resistant elastic notch rings combined.

[0020] Further, the thickness, axial thickness, and opening free gap of the sand scraping ring are as follows,

[0021]

[0022] where, t — the radial thickness of a single notch ring, mm;

[0023] P — the maximum working pressure difference of the plunger, MPa;

[0024] α — the well deviation angle, °;

[0025] S — the stroke frequency, min -1 ;

[0026] D — the diameter of the notch ring, m;

[0027] h = (0.4 - 0.8)t

[0028] where, h — the axial thickness, mm;

[0029] S0 = (3 - 4)t

[0030] where, S0 — the opening free gap, mm.

[0031] Further, the number of the sand scraping rings is as follows according to the pressure difference, stroke frequency, and well deviation angle,

[0032] N = P * S tanɑ / 2.5;

[0033] where, N — the number of notch rings;

[0034] P — the maximum working pressure difference of the plunger, MPa;

[0035] S - stroke frequency, min -1 ;

[0036] α - well deviation angle, °.

[0037] Furthermore, the angle between any two of the at least two notched rings is 360° / N.

[0038] To achieve the above object, the present invention adopts the following technical solutions:

[0039] A method for using a sand scraping oil production pump includes the following steps:

[0040] S1. Assemble a sand scraping oil production pump;

[0041] S2. Before lowering into the well, connect the plunger with the sand scraping ring to the lower joint of the disconnecting joint, then use a tooling to pre - place the plunger in the pump barrel. The lower end of the sucker rod is provided with the upper end of the disconnecting joint. After bumping the pump, the disconnecting joint is docked, and then conduct a trial pumping and pressure holding test. After passing the test, start pumping production;

[0042] S3. When the plunger moves upward, the intake valve is opened by the pressure difference, and the formation produced fluid passes through the intake valve and enters the pump barrel;

[0043] Then the plunger moves downward. The intake valve is a check valve and is in a closed state at this time. The produced fluid is squeezed above the pump barrel, enters the plunger through the drain valve, then enters the interior of the inner tube through the inner tube hole of the inner tube, and then reaches the upper part of the plunger through the liquid outlet hole of the upper joint. In this way, normal oil pumping production is realized by reciprocation;

[0044] S4. When sand grains enter the gap, the sand scraping ring scrapes away the sand grains, and the liquid separates under the action of gravity inside the plunger. The upper oil can enter the gap between the plunger and the pump barrel through the lubrication hole to lubricate the sand scraping ring, and the crude oil adheres to the inner wall of the pump barrel. After multiple accumulations, the sand grains are discharged from the pump barrel;

[0045] S5. When the sand scraping ring wears, under the action of elastic force, the sand scraping ring expands radially to maintain an interference fit with the pump barrel.

[0046] To achieve the above object, the present invention adopts the following technical solutions:

[0047] An assembling method for a sand scraping oil production pump includes the following steps:

[0048] A1. Connect the pump barrel with the intake valve, apply anaerobic adhesive, and tighten with special equipment;

[0049] A2. Connect the inner tube with the upper joint, apply thread sealant and tighten. Connect the upper joint with the plunger, apply thread sealant and tighten. Connect the plunger with the drain valve, apply thread sealant and tighten;

[0050] A3. Apply butter to the upper surface of the single-piece notched ring and install it into the sand scraping groove of the plunger. After applying butter to the upper and lower surfaces of the second piece, rotate it 360° / N with respect to the notch of the first piece. Then, sequentially install the remaining notched rings into the sand scraping groove. Apply butter to the lower surface of the last piece and install it into the sand scraping groove to complete the installation of the sand scraping ring.

[0051] A4. Conduct a leakage test on the clearance between the plunger and the pump barrel. Radially compress the sand scraping ring composed of multiple notched rings and install it into a tooling with the same diameter as the pump barrel. Then, dock the tooling with the pump barrel and slowly push the plunger into the pump barrel. Subsequently, conduct the test using the conventional test method for the leakage amount of the clearance between the plunger and the pump barrel of a sucker rod pump.

[0052] The present invention has the following beneficial effects compared with the prior art:

[0053] 1. Achieve zero-clearance sand scraping and solve the problem of sand jamming the plunger.

[0054] 2. Provide a group design method, an assembly test method, and a construction method, which guarantee the long-term operation of the pipe string. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 is a schematic structural diagram of a sand scraping sucker rod pump of the present invention Figure 1 ;

[0056] Figure 2 is a schematic structural diagram of a sand scraping sucker rod pump of the present invention Figure 2 ;

[0057] Figure 3 is a schematic structural diagram of the notched ring of a sand scraping sucker rod pump of the present invention;

[0058] In the figure: 1 upper sub; 2 liquid outlet; 3 sand scraping ring; 4 lubricating hole; 5 plunger; 6 inner pipe; 7 inner pipe hole; 8 drain valve; 9 pump barrel; 10 inlet valve; t radial thickness of the single-piece notched ring; h axial thickness; S0 opening free clearance; N number of notched rings. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0059] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0060] Embodiment 1:

[0061] Please refer to Figures 1 to 2, a sand scraping sucker rod pump provided by the present invention includes a plunger 5 and a pump barrel 9. The plunger 5 is arranged in the pump barrel 9. An upper joint 1 is arranged at the upper end of the plunger 5. A liquid outlet 2 is arranged on the upper joint 1. A drain valve 8 is arranged at the lower end of the plunger 5. A liquid inlet valve 10 is arranged at the lower end of the pump barrel 9.

[0062] The inner wall of the lower end of the upper joint 1 is connected to an inner tube 6. The inner tube 6 is shorter than the length of the plunger 5. The inner tube 6 is provided with an inner tube hole 7. The produced liquid can enter the upper joint 1 through the inner tube hole 7 and enter the upper space of the plunger 5.

[0063] The outer wall of the plunger 5 is provided with a lubricating hole 4. At least one sand scraping groove is arranged on the outer wall of the plunger 5. A sand scraping ring 3 is embedded in each sand scraping groove;

[0064] When the sand scraping ring 3 and the sand scraping groove are one, they are arranged above the lubricating hole 4.

[0065] The inner tube hole 7 is arranged below the lubricating hole 4. The inner tube hole 7 can be arranged on the side wall of the inner tube 6, such as Figure 1 , or can be arranged at the bottom of the inner tube 6, such as Figure 2 .

[0066] Arranging the inner tube hole 7 below the lubricating hole 4 can make the upper space inside the plunger 5 full of crude oil, so that only crude oil overflows from the lubricating hole 4.

[0067] When the sand scraping ring 3 and the sand scraping groove are at least two, they are distributed above and below the lubricating hole 4.

[0068] The free outer diameter of the sand scraping ring 3 is greater than the inner diameter of the pump barrel 9. The sand scraping ring 3 and the pump barrel 9 are in an elastic interference fit. The sand scraping ring 3 can contract and expand under different radial forces.

[0069] The sand scraping ring 3 is composed of at least two anti-corrosion and wear-resistant elastic notched rings combined; the surface roughness of the upper and lower surfaces of the notched ring is not less than 0.4.

[0070] Please refer to Figure 3 , the design formula of the sand scraping ring 3,

[0071]

[0072] Among them, t—the radial thickness of a single notched ring, mm;

[0073] P—the maximum working pressure difference of the plunger, MPa;

[0074] α—the well deviation angle, °;

[0075] S—the stroke per minute, min -1 ;

[0076] D —— Notch ring diameter, m;

[0077] h = (0.4 - 0.8)t

[0078] Wherein, h —— Axial thickness, mm;

[0079] S0 = (3 - 4)t

[0080] Wherein, S0 —— Open free clearance, mm;

[0081] N = P * S tanɑ / 2.5;

[0082] Wherein, N —— Number of notch rings;

[0083] P —— Maximum working pressure difference of the plunger, MPa;

[0084] S —— Strokes per minute -1 ;

[0085] α —— Well deviation angle, °.

[0086] Example 2:

[0087] Based on Example 1, this example provides a method for using a sand scraping oil production pump, including the following steps:

[0088] S1. Assemble a sand scraping oil production pump;

[0089] S2. Before lowering the pump into the well, connect the plunger 5 equipped with the sand scraping ring 3 to the lower joint of the disconnecting device, then use the tooling to pre-place the plunger 5 in the pump barrel 9. The lower end of the sucker rod is equipped with the upper end of the disconnecting device. After bumping the pump, the disconnecting device is docked, and then conduct a trial pumping and pressure holding test. After passing the test, start the pumping production;

[0090] S3. When the plunger moves upward, the inlet valve 10 is opened by the pressure difference, and the formation produced fluid passes through the inlet valve 10 and enters the pump barrel 9;

[0091] Then the plunger 5 moves downward. The inlet valve 10 is a check valve and is in the closed state at this time. The produced fluid is squeezed to the upper part of the pump barrel 9, enters the plunger 5 through the drain valve 10, then enters the inner part of the inner tube 6 through the inner tube hole 7 of the inner tube 6, and then reaches the upper part of the plunger 5 through the liquid outlet hole 2 of the upper joint 1. This process is repeated to achieve normal oil production;

[0092] S4. When sand grains enter the gap, the sand scraping ring 3 scrapes away the sand grains, and the liquid separates under the action of gravity inside the plunger 5. The upper oil can enter the gap between the plunger 5 and the pump barrel 9 through the lubricating hole 4 to lubricate the sand scraping ring 3. The crude oil adheres to the inner wall of the pump barrel 9. After multiple accumulations, the sand grains are discharged from the pump barrel 9;

[0093] S5. When the scraping ring 3 wears, under the action of elastic force, the scraping ring 3 expands radially to maintain an interference fit with the pump barrel 9.

[0094] Embodiment 3:

[0095] Based on Embodiment 1, this embodiment provides an assembly method for a sand scraping oil production pump:

[0096] A1. Connect the pump barrel 9 with the inlet valve 10, apply anaerobic adhesive, and tighten it with special equipment;

[0097] A2. Connect the inner pipe 6 with the upper joint 1, apply thread sealant and tighten. Connect the upper joint 1 with the plunger 5, apply thread sealant and tighten. Connect the plunger 5 with the drain valve 8, apply thread sealant and tighten;

[0098] A3. Apply butter on the upper surface of the single-piece notched ring and install it into the sand scraping groove of the plunger 5. Apply butter on the upper and lower surfaces of the second piece and rotate it by a certain angle (360° / N) with respect to the notch of the first piece. Then sequentially install the remaining notched rings into the sand scraping groove. Apply butter on the lower surface of the last piece and install it into the sand scraping groove to complete the installation of the scraping ring 3;

[0099] A4. Conduct a clearance leakage test between the plunger 5 and the pump barrel 9. Radially compress the scraping ring 3 composed of multiple notched rings and install it into a tooling with the same diameter as the pump barrel. Then dock the tooling with the pump barrel 9 and slowly push the plunger 5 into the pump barrel 9. Then use the conventional method for testing the clearance leakage between the plunger 2 and the pump barrel 9 of an oil production pump for testing.

[0100] In this application, all components themselves that are not elaborated and the connection methods of various components in this application belong to the well-known technologies in this technical field and can be directly applied without further elaboration.

[0101] In the present invention, the term "multiple" refers to two or more, unless otherwise clearly defined. Terms such as "install", "connect", "join", "fix" and the like should be understood in a broad sense. For example, "connect" can be a fixed connection, a detachable connection, or an integral connection; "join" can be a direct connection or an indirect connection through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0102] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by terms such as "upper", "lower", "left", "right", "front", "rear", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or unit referred to must have a specific direction, be constructed and operated in a specific orientation, and therefore, should not be construed as a limitation to the present invention.

[0103] In the description of this specification, the descriptions of terms such as "one embodiment", "some embodiments", "specific embodiments", etc. mean that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or instance. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0104] The foregoing are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A sand scraping oil extraction pump, comprising a plunger and a pump barrel, the plunger is arranged in the pump barrel, and is characterized in that, It also includes a sand scraping ring; The outer wall of the plunger is provided with lubricating holes, and a liquid separation mechanism is arranged inside the plunger; At least one sand scraping groove is arranged on the outer wall of the plunger, and a sand scraping ring is embedded in each sand scraping groove.

2. The sand scraping oil extraction pump according to claim 1, characterized in that, An upper joint is arranged at the upper end of the plunger, and a liquid outlet is arranged on the upper joint. A drain valve is arranged at the lower end of the plunger, and a liquid inlet valve is arranged at the lower end of the pump barrel; The liquid separation mechanism is an inner tube. The inner wall at the lower end of the upper joint is connected to the inner tube. The inner tube is shorter than the length of the plunger. An inner tube hole is arranged below the lubricating hole on the inner tube; The inner tube hole can be arranged on the side wall or the bottom of the inner tube.

3. The sand scraping oil extraction pump according to claim 1, characterized in that, When there is one sand scraping ring and one sand scraping groove, they are arranged above the lubricating hole.

4. A sand scraping oil extraction pump according to claim 1, characterized in that, When there are at least two sand scraping rings and sand scraping grooves, they are distributed above and below the lubricating hole.

5. The sand scraping oil extraction pump according to claim 1, characterized in that, The free outer diameter of the sand scraping ring is greater than the inner diameter of the pump barrel, and the sand scraping ring and the pump barrel are in elastic interference fit.

6. The sand scraping oil extraction pump according to claim 1, characterized in that, The sand scraping ring is composed of at least two anti-corrosion and wear-resistant elastic notched rings combined.

7. The sand scraping oil extraction pump according to claim 6, characterized in that, The thickness, axial thickness, and opening free gap of the sand scraping ring are as follows: where t is the radial thickness of a single notched ring, in mm; P is the maximum working pressure difference of the plunger, in MPa; α is the well deviation angle, in °; S - stroke frequency, min -1 ; D is the diameter of the notched ring, in m; h = (0.4 - 0.8)t where h is the axial thickness, in mm; S0 = (3 - 4)t where S0 is the opening free gap, in mm.

8. The sand scraping oil extraction pump according to claim 6, characterized in that, The number of the sand scraping rings is determined according to the pressure difference, stroke frequency, and well deviation angle as follows: N = P * S tanɑ / 2.5; where N is the number of notched rings; P is the maximum working pressure difference of the plunger, in MPa; S - strokes per minute -1 ; α is the well deviation angle, in °.

9. The sand scraping oil extraction pump according to claim 8, characterized in that, The angle between every two of the at least two notched rings is 360° / N.

10. A method for using a sand scraping oil extraction pump, characterized in that, It includes the following steps: S1. Assemble a sand scraping oil pump; S2. Before lowering the well, connect the plunger with the sand scraping ring installed to the lower joint of the disconnecting joint. Then, use a tooling to pre-place the plunger in the pump barrel. The lower end of the sucker rod is provided with the upper end of the disconnecting joint. After bumping the pump, the disconnecting joint is docked, and then conduct a trial pumping and pressure holding test. After passing the test, start the pumping production; S3. When the plunger moves upward, the liquid inlet valve is opened by the pressure difference, and the formation produced fluid passes through the liquid inlet valve and enters the pump barrel; Then the plunger moves downward. The liquid inlet valve is a check valve and is in the closed state at this time. The produced fluid is squeezed to the upper part of the pump barrel and enters the plunger through the drain valve, then enters the inside of the inner tube through the inner tube hole of the inner tube, and then reaches the upper part of the plunger through the liquid outlet hole of the upper joint. In this way, the normal pumping production is realized by reciprocating; S4. When sand grains enter the gap, the sand scraping ring scrapes away the sand grains, and the liquid separates under the action of gravity inside the plunger. The upper oil can enter the gap between the plunger and the pump barrel through the lubricating hole to lubricate the sand scraping ring. The crude oil adheres to the inner wall of the pump barrel. After multiple accumulations, the sand grains are discharged from the pump barrel; S5. When the sand scraping ring wears, under the action of the elastic force, the sand scraping ring expands radially to maintain an interference fit with the pump barrel.

11. An assembly method of a sand scraping oil extraction pump, characterized in that, It includes the following steps: A1. Connect the pump barrel with the liquid inlet valve, apply anaerobic glue, and tighten it with special equipment; A2. Connect the inner tube with the upper joint, apply glue to the thread and tighten it. Connect the upper joint with the plunger, apply glue to the thread and tighten it. Connect the plunger with the drain valve, apply glue to the thread and tighten it; A3. Apply butter to the upper surface of the single-piece notched ring and install it into the sand scraping groove of the plunger. After applying butter to the upper and lower surfaces of the second piece, rotate it 360° / N with the notch of the first piece. Then, install the remaining notched rings into the sand scraping groove in sequence. Apply butter to the lower surface of the last piece and install it into the sand scraping groove to complete the installation of the sand scraping ring. A4. Plunger and pump barrel clearance leakage test: Radially compress the sand scraping ring composed of multiple notched rings and install it into a tooling with the same diameter as the pump barrel. Then, dock the tooling with the pump barrel and slowly push the plunger into the pump barrel. Then, use the conventional test method for the clearance leakage between the plunger and the pump barrel of a sucker rod pump to conduct the test.

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