Oil well pump

Abstract

The invention discloses an oil well pump which comprises an oil outlet valve, a head thread, an internal thread plunger, an oil inlet valve, a traveling valve, an oil inlet plug, an upper coupling, a wear-resistant ring, a pump cylinder, a middle coupling, a lower coupling, a connecting pipe, a pressure reducing valve assembly, a fixed valve connector and a gas and sand anchor. The upper end of the double-end thread is in threaded connection with the oil outlet valve; the lower end is connected with a plunger; the lower end of the plunger is in threaded connection with the oil inlet valve, the traveling valve is placed in the oil inlet valve, the oil inlet plug is in threaded connection with the oil inlet valve and abuts against a valve seat of the traveling valve, the upper portion of the upper coupling is in threaded connection with the oil pipe through the oil pipe, the lower portion of the upper coupling is in threaded connection with the pump cylinder, and the top of the pump cylinder abuts against a wear-resisting ring arranged between an inner ring of the upper coupling and an outer ring of the oil outlet valve. The lower end of the connecting pipe is connected with a pressure reducing valve through a lower coupling, the pressure reducing valve is connected with a fixing valve connector through threads, and the fixing valve connector is connected with the upper portion of a gas and sand anchor; a nickel carbide coating is arranged on the surface of an inner hole of the pump cylinder, a tungsten carbide coating is arranged on the outer surface of the internal thread plunger, and the nickel carbide coating and the tungsten carbide coating form a corrosion-resistant friction pair with the potential difference smaller than or equal to 0.3 V.

Description

Technical Field

[0001] This invention belongs to the field of oil extraction equipment technology, specifically relating to an oil pump that achieves self-adaptation under multiple working conditions such as corrosion, scaling, wear, waxing, high gas-oil ratio, deep wells, heavy oil thermal recovery, and deviated wells through modular design. Background Technology

[0002] As oil wells are developed, the downhole environment becomes increasingly harsh, and complex well conditions place higher performance demands on pumping units. Currently, traditional pumping units suffer from the following shortcomings: single materials and structures cannot cope with complex well conditions, such as high H2S gas content + high sand content wells, leading to corrosion and wear of the pump barrel and plunger; high gas-oil ratios + well inclination reduce the adaptability of single gas-proof pumping units and deviated well pumping units, even causing failure; in deep well conditions, the risks of pump barrel bursting, valve ball and seat impact failure, and insufficient strength at various threads of the plunger assembly leading to fracture are increased; heavy oil thermal recovery requires product structures that meet field operation needs, while scaling and high oil viscosity make the pumping unit product structure complex and variable. Summary of the Invention

[0003] To address the technical problems existing in the prior art, this invention provides an oil pump that adopts the structure of a conventional oil pump. It solves the problems of oil pumps caused by different degrees of corrosion, wear, deep wells, and high temperatures in downholes through changes in materials, surface treatment, and product structure. It also solves the problems of oil pumps caused by high oil-gas ratios, well deviation, sand content, heavy oil, scaling, and wax deposition by directly replacing or adding functional modules to the pump.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows: An oil pump includes an oil outlet valve, a threaded plunger, an internally threaded plunger, an inlet valve, a traveling valve, an inlet plug, an upper coupling, a wear ring, a pump barrel, an intermediate coupling, a lower coupling, a connecting pipe, a pressure reducing valve assembly, and a fixed valve connector. The upper part of the oil outlet valve is connected to a sucker rod, and the upper end of the double-threaded plunger is threadedly connected to the oil outlet valve. The lower end is connected to the plunger; the lower end of the plunger is threadedly connected to the inlet valve, the traveling valve rests inside the inlet valve, the inlet plug is threadedly connected to the inlet valve and presses against the valve seat of the traveling valve, and the upper part of the upper coupling is connected to the oil outlet valve. The oil pipe is connected by a threaded connection at the bottom, and the pump barrel is connected by a threaded connection at the bottom. The top of the pump barrel is tightly fitted with a wear-resistant ring set between the inner ring of the upper coupling and the outer ring of the oil outlet valve. The lower end of the pump barrel is threaded to the middle coupling, and the lower end of the middle coupling is connected to the connecting pipe. The lower end of the connecting pipe is connected to the pressure reducing valve through the lower coupling. The pressure reducing valve is fixed to the valve connector by a threaded connection. The inner surface of the pump barrel is provided with a nickel carbide plating layer, and the outer surface of the internally threaded plunger is provided with a tungsten carbide coating. The nickel carbide plating layer and the tungsten carbide coating form a corrosion-resistant friction pair with a potential difference ≤0.3V. As a further technical solution, the base material of the pump cylinder is 1Cr5Mo, the wall thickness is 8mm or 10mm or more, and the minimum yield strength of the matrix is ​​70Ksi.

[0005] As a further technical solution, the base material of the internal threaded plunger is alloy steel, and the surface is sprayed with a tungsten carbide non-metallic ceramic coating; the sand sinker of the internal threaded plunger is formed by spray welding.

[0006] As a further technical solution, the floating valve and pressure reducing valve assembly adopts a combination of zirconia ceramic valve ball and tungsten carbide valve seat, and the inner hole of the tungsten carbide valve seat is sprayed with high-density polytetrafluoroethylene material.

[0007] As a further technical solution, the pressure reducing valve assembly consists of two valve covers connected in series, with two ball valves installed inside. The upper part is a sealing ball valve, and the lower part is a pressure reducing ball valve. The valve ball opening impact position is an inclined surface with a through hole to increase the liquid flow channel area.

[0008] As a further technical solution, it also includes a gas-sand anchor under the pump, with a fixed valve connector connected to the upper part of the gas-sand anchor under the pump; the gas-sand anchor under the pump includes an outer inlet pipe, a separation pipe, an inlet pipe, a positioning connector, and a sedimentation chamber; the upper part of the outer inlet pipe is provided with an oblique exhaust hole, and the lower part is provided with an oblique inlet hole, through which hydraulic fluid can enter the interior; the outer surface of the separation pipe is provided with a spiral blade that surrounds the circumference; the spiral blade is provided with a separation pipe inlet at the bottom; when the liquid enters through the oblique inlet, it is accelerated and divided by the spiral, the sand and gravel are thrown to the outer circle and deposited into the sedimentation chamber, the liquid and gas enter through the separation pipe inlet, the gas rises and is discharged through the oblique exhaust hole, the liquid settles and enters through the lower inlet of the inlet pipe, and rises to reach the inlet of the oil pump. As a further technical solution, the valve cover of the oil inlet valve adopts a guided full-flow valve with internal guide ribs; and a wear-resistant ring is added between the upper part of the pump barrel and the coupling.

[0009] As a further technical solution, the length of the internally threaded plunger is greater than the length of the pump barrel.

[0010] As a further technical solution, the oil outlet hole of the oil inlet valve is provided with a through hole. As a further technical solution, the pump cylinder wall thickness is 8mm or 10mm or more. The beneficial effects of this invention are as follows: 1. The pump barrel of this invention employs a nickel carbide plating layer (0.076mm) on the inner bore surface, forming a corrosion-resistant friction pair with a potential difference ≤0.3V with a tungsten carbide coating (0.15mm) on the outer surface of the internally threaded plunger. Under high pressure, for oil wells with hydrogen sulfide content of 10000 PPM, carbon dioxide content of 1500 PPM, and high water content, its service life can reach over 1000 days. It possesses high hardness and high wear resistance, making it suitable for use in wells containing high-hardness quartz sand. Furthermore, combining the non-magnetic nature of the nickel carbide coating on the pump barrel with the metal-ceramic tungsten carbide coating on the plunger, based on the characteristics of ceramics, effectively delays scaling and mitigates the impact of high gas-oil ratios on the pump. The internally threaded plunger increases the flow channel area, reduces flow resistance, and lowers the impact of heavy oil on the pump. A traveling valve is installed at the lower part of the plunger to reduce wear on the upper valve cover, preventing damage to the valve cover and reducing ineffective pump chamber space.

[0011] 2. This invention improves the pump barrel material and wall thickness, enhancing material performance. The minimum yield strength of the matrix is ​​70 Ksi, solving the problem of pump barrel bursting in deep pumps. Combined with nickel carbide plating, it can effectively solve the pitting corrosion problem. 3. The base material of the plunger of the present invention is alloy steel, and the surface is sprayed with tungsten carbide non-metallic ceramic coating; the plunger sand settling groove is formed by spray welding, which solves the corrosion problem of the sand settling groove; 4. The traveling valve and pressure reducing valve assembly of this invention uses a combination of zirconia ceramic valve ball and tungsten carbide valve seat, which is suitable for use in highly corrosive oil wells and magnetized oil wells; the inner hole of the tungsten carbide valve seat is coated with high-density polytetrafluoroethylene material, which can effectively delay the scaling of the valve seat inner hole and grinding surface, and solve the problems of inner hole blockage and sealing failure; the low-density ceramic valve ball is lightweight, which reduces the valve ball's fall speed, especially in gas-bearing wells and oil wells with insufficient fluid supply, reducing damage to the sealing surface on the valve seat and delaying valve ball and valve seat sealing failure; the pressure reducing valve assembly adopts a pressure reducing valve structure composed of double ball valves to prevent splash damage caused by high pressure differential in deep wells when the valve ball is opened; 5. To address the impact of well deviation on the oil pump, guide ribs are added inside the valve cover of the inlet valve to effectively reduce the drift of the valve ball during opening and closing. At the same time, a wear-resistant ring is added between the upper part of the pump barrel and the coupling to reduce the uneven wear of the plunger on the pump barrel.

[0012] 6. To address the impact of gravel on the oil pump, the pump barrel of this invention is shorter than the long plunger structure: during operation, when the plunger enters and exits the pump barrel, the gap between the pump barrel port and the plunger surface, where gravel enters the pump barrel and plunger, is eliminated. At the same time, the gas-sand anchor under the pump can be used in oil wells with a displacement of 90m3. It adopts the principles of cyclone separation and gravity settling to solve the problem of free gas and gravel at the oil pump inlet. Attached Figure Description

[0013] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0014] Figure 1 A simplified diagram of the frame of a full-function oil pump; Figure 2(a) and Figure 2(b) are schematic diagrams of the oil inlet valve; Figure 3 This is a schematic diagram of a pressure reducing valve. Figure 4 Schematic diagram of wear-resistant ring Figure 1 ; Figure 5 Schematic diagram 2 for wear-resistant ring; Figure 6 Schematic diagram of wear-resistant ring Figure 3 ; Figure 7 Schematic diagram of the air-sand anchor under the pump; The diagram exaggerates the spacing or dimensions between parts to show their positions; the diagram is for illustrative purposes only.

[0015] 1. Oil outlet valve, 2. Double-ended thread, 3. Internal threaded plunger, 4. Oil inlet valve, 5. Floating valve, 6. Oil inlet plug, 7. Upper coupling, 8. Wear-resistant ring; 9. Pump cylinder; 10. Intermediate coupling; 11. Lower coupling; 12. Connecting pipe; 13. Pressure reducing valve assembly; 14. Fixed valve connector; 15. Air sand anchor. 15-1. Inlet pipe; 15-2. Separator pipe; 15-3. Inlet pipe; 15-4. Positioning connector; 15-5. Sand settling chamber; 15-1-1. Angled vent hole; 15-2-2. Inlet of separator pipe; 8-1. Wear-resistant coupling; 8-2. Wear-resistant ring assembly; Detailed Implementation It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0016] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, unless otherwise expressly indicated by the invention, the singular form is also intended to include the plural form. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof. For ease of description, the words "up," "down," "left," and "right" appearing in this invention only indicate that they are consistent with the up, down, left, and right directions of the accompanying drawings themselves, and do not limit the structure. They are merely for the purpose of facilitating the description of this invention and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0017] As described in the background section, there are shortcomings in the existing technology. In order to solve the above-mentioned technical problems, the present invention proposes an oil pump.

[0018] In a typical embodiment of the present invention, such as Figure 1 As shown, Figure 1 The invention presents an oil pump comprising: an oil outlet valve 1, a double-threaded 2, an internally threaded plunger 3, an oil inlet valve 4, a floating valve 5, an oil inlet plug 6, an upper coupling 7, a wear-resistant ring 8, a pump barrel 9, an intermediate coupling 10, a lower coupling 11, a connecting pipe 12, a pressure reducing valve assembly 13, a fixed valve connector 14, and an air sand anchor 15. The upper part of the oil outlet valve 1 is connected to the sucker rod, and the upper end of the double-threaded 2 is threadedly connected to the oil outlet valve 1; the lower end is connected to the plunger 3; the lower end of the plunger 3 is threadedly connected to the oil inlet valve 4, the traveling valve 5 is placed inside the oil inlet valve 4, the oil inlet plug 6 is threadedly connected to the oil inlet valve 4 and the oil inlet plug 6 is pressed against the valve seat 5 of the traveling valve; the upper part of the upper coupling 7 is threadedly connected to the oil pipe, and the lower part is threadedly connected to the pump barrel 9. The top of the pump barrel 9 is pressed against the wear-resistant ring 8 set between the inner ring of the upper coupling 7 and the outer ring of the oil outlet valve 1. The lower end of the pump barrel is threadedly connected to the intermediate coupling 10, the lower end of the intermediate coupling 10 is connected to the connecting pipe 11, the lower end of the connecting pipe 11 is connected to the pressure reducing valve 13 through the lower coupling 12, the pressure reducing valve 13 is threadedly connected to the fixed valve joint 14, and the fixed valve joint 14 is connected to the upper part of the gas sand anchor 15. In order to solve the problems of oil pump caused by corrosion, wear, deep wells, high temperature, etc., this embodiment is further improved in the following aspects; The friction pair between the pump barrel and the internally threaded plunger 3 is optimized. The pump barrel 9 adopts a nickel carbide plating layer (0.076mm) on the inner surface of the bore, which forms a corrosion-resistant friction pair with a potential difference ≤0.3V with the tungsten carbide coating (0.15mm) on the outer surface of the internally threaded plunger 3. Under high pressure, for oil wells with hydrogen sulfide content of 10000PPM, carbon dioxide content of 1500PPM, and high water content, the service life can reach more than 1000 days. It has high hardness and high wear resistance, and is suitable for use in wells containing high-hardness quartz sand. In addition, combined with the non-magnetic nickel carbide coating of the pump barrel and the metal-ceramic tungsten carbide coating of the plunger, the scaling phenomenon can be effectively delayed based on the characteristics of ceramic. Furthermore, improvements were made to the pump barrel 9. The base material of the pump barrel 9 is 1Cr5Mo, and the wall thickness is 8mm (or 10mm or more). The cold rolling process was adopted to improve the material properties. The minimum yield strength of the matrix is ​​70Ksi, which solves the problem of pump barrel cracking when the deep pump is hanging. In combination with the nickel carbide plating, it can effectively solve the pitting corrosion problem. Furthermore, improvements are made to the internal threaded plunger 3. The base material of the internal threaded plunger 3 is alloy steel, and the surface is sprayed with a tungsten carbide non-metallic ceramic coating. The sand settling groove of the internal threaded plunger 3 is formed by spray welding, which solves the corrosion problem of the sand settling groove. Furthermore, improvements were made to the ball valve inside the traveling valve 5 and the pressure reducing valve assembly 13. The ball valve of the traveling valve 5 and the pressure reducing valve assembly 13 uses a zirconia ceramic ball with a tungsten carbide seat, which is suitable for use in highly corrosive oil wells and magnetized oil wells. The inner hole of the tungsten carbide seat is coated with high-density polytetrafluoroethylene material, which can effectively delay the scaling of the inner hole and grinding surface of the valve seat and solve the problems of inner hole blockage and sealing failure. The low-density ceramic ball is lightweight, which reduces the ball's fall speed, especially in gas-bearing wells and oil wells with insufficient fluid supply, reducing damage to the sealing surface on the valve seat and delaying the failure of the ball and valve seat seal. The pressure reducing valve structure composed of dual fixed valves prevents splash damage caused by the high pressure differential in deep wells when the ball is opened.

[0019] Furthermore, all the components mentioned above, except for the pump barrel, plunger, valve ball, and valve seat, are made of 2507 duplex stainless steel or 20Cr13 martensitic stainless steel with QPQ treatment to solve the problem of material damage in highly corrosive environments. In addition, QPQ treatment improves the wear resistance and fatigue strength of the standard parts surface. The valve cover adopts an integral valve cover, eliminating threaded connections and improving strength.

[0020] To address the pumping problems caused by high gas-oil ratio, well deviation, scaling, wax deposition, and heavy oil, this embodiment further improves upon these issues in the following aspects. To address the impact of a high gas-oil ratio on the oil pump, in this embodiment, the internal threaded plunger 3 has the traveling valve 5 positioned at the bottom. A single traveling valve is selected and placed under the plunger to reduce the ineffective pump chamber space. In conventional oil pumps, the traveling valve 5 is placed above the internal threaded plunger 3, and the inner hole of the internal threaded plunger 3 is ineffective space during operation. Therefore, in this embodiment, the internal threaded plunger 3 has the traveling valve 5 positioned at the bottom.

[0021] Furthermore, a pump-mounted air-sand anchor 15 was added, which is applicable to pumps with a displacement of 90m³ / h. 3 Used in oil wells, it employs the principles of cyclone separation and gravity settling to address the effects of free gas and gravel at the pump inlet. For example... Figure 5The diagram shown is of a sand anchor under the pump. This component is a modular unit outside of the independent overall structure diagram. It is set and connected to the lower end of the fixed valve, that is, the liquid inlet of the pump body. A certain number of oil pipes can be connected to its lower part as sand sinking pipes. Its structure mainly includes an outer inlet pipe 15-1, a separation pipe 15-2, an inlet pipe 15-3, a positioning connector 15-4, and a sedimentation chamber 15-5. The outer inlet pipe 15-1 is provided with an inclined vent hole 15-1-1 at the top and an inclined inlet hole 15-1-2 at the bottom, allowing liquid to enter the interior through the inclined inlet hole 15-1-2. The outer surface of the separation pipe 15-2 is provided with a spiral blade 15-2-1 that surrounds the circumference. The inlet of the separation pipe 15-2-2 is located below the spiral blade. When the liquid enters through the inclined inlet 15-1-2, it is accelerated and divided by the spiral. The sand and gravel are thrown to the outer circle and deposited into the sedimentation chamber 15-5. Liquid and gas enter through the inlet 15-2-2 of the separation pipe. The gas rises and is discharged through the inclined vent hole 15-1-1. The liquid settles and enters through the lower inlet of the inlet pipe 15-3, rising to reach the inlet of the oil pump. To address the impact of well deviation on the oil pump, this embodiment further improves the process in the following aspects; The valve cover of inlet valve 4 adopts a guided full-flow valve (see Figures 2(a) and 2(b)): guide ribs are added inside the valve cover to effectively reduce the drift of the valve ball during opening and closing; in addition, compared with conventional valve covers, the valve ball's bounce impact position is changed from a solid structure to a through-hole design to increase the fluid flow channel. Moreover, the valve cover adopts an integral valve cover, eliminating threaded connections and improving strength.

[0022] Furthermore, by adding a wear-resistant ring between the upper part of the pump barrel and the coupling, the uneven wear of the plunger on the pump barrel can be reduced; furthermore, such as Figure 4 , Figure 5 , Figure 6 As shown, a hard wear-resistant alloy ring is provided at the top of the pump barrel. When the plunger descends, it can wipe the surface to prevent adhering particles from entering the gap between the pump barrel and the plunger and causing damage. In addition, it can also prevent uneven wear on the upper part of the pump barrel when encountering well inclination or when the plunger's descent is obstructed. In this embodiment, the wear-resistant ring 8 includes two parts: a wear-resistant coupling 8-1 and a wear-resistant ring assembly 8-2. The wear-resistant ring assembly 8-2 is assembled and fixed by the pump barrel 9 and the wear-resistant coupling 8-1. The wear-resistant ring assembly 8-2 is composed of a wear-resistant alloy ring and a sealing ring. The wear-resistant alloy can be made of cobalt-chromium-tungsten alloy or tungsten carbide alloy. The sealing ring material can be nitrile rubber or fluororubber.

[0023] Furthermore, to mitigate the impact of gravel on the oil pump, this embodiment employs a short pump barrel and long plunger structure (see attached diagram). Figure 1That is, the length of the internally threaded plunger 3 is greater than the length of the pump barrel 9. During operation, when the plunger enters and exits the pump barrel, the gap between the pump barrel port and the plunger surface, where sand and gravel enter the pump barrel and plunger, is created. Specifically, based on the original overall structural diagram, and according to the stroke selection, the length of the pump barrel is shortened to between 0.9m and 1.5m, and the length of the plunger 4 is between 2.8m and 9m; intermediate couplings and extension cylinders can be installed. Furthermore, a gas-sand anchor under the pump is adopted, as described above. The gas-sand anchor under the pump is suitable for use in oil wells with a displacement of 90m3. It adopts the principles of cyclone separation and gravity settling to solve the problem of free gas and gravel at the pump inlet.

[0024] Furthermore, in order to address the impact of heavy oil on the oil pump, the valve cover of the inlet valve 4 in this embodiment is shown in Figures 2(a) and 2(b), and the oil outlet is designed with a through-hole pattern to increase the flow channel area and reduce the flow resistance. Furthermore, an internally threaded plunger 3 (overall view) is adopted: to increase the flow channel area and reduce the flow resistance.

[0025] To address the impact of scaling and wax buildup on the oil pump, a Teflon coating is applied to the inner bore of the valve seat of the pressure reducing valve assembly 13 and the inlet valve 4 to slow down scaling.

[0026] To address the impact of deep-mounted pumps on the oil pump, the pump barrel wall thickness was increased from 6.35mm to 8mm and 10mm.

[0027] Furthermore, the upper valve cover of the internal threaded plunger 3 does not support the traveling valve, reducing wear on the upper valve cover from the traveling valve and preventing wear and damage to the valve cover (see appendix). Figure 1 ); Furthermore, such as Figure 3 As shown, in order to reduce the splash damage of high-speed liquid flow to the sealing ball valve, the pressure reducing valve assembly 13 in this embodiment consists of two valve covers connected in series and two fixed valves. The upper part is a sealing ball valve and the lower part is a pressure reducing ball valve. Its main function is to reduce the splash damage of high-speed liquid flow to the sealing ball valve. The valve ball opening impact position is an inclined surface and is provided with a through hole to increase the liquid flow channel area.

[0028] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An oil pump, characterized in that, Includes an oil delivery valve, threaded plunger, internal threaded plunger, inlet valve, traveling valve, inlet plug, upper coupling, wear ring, pump barrel, intermediate coupling, lower coupling, connecting pipe, pressure reducing valve assembly, and fixed valve connector; the upper part of the oil delivery valve is connected to the sucker rod, and the upper end of the double-threaded plunger is threaded to the oil delivery valve; the lower end is connected to the plunger; the lower end of the plunger is threaded to the inlet valve, the traveling valve rests inside the inlet valve, the inlet plug is threaded to the inlet valve and the inlet plug is pressed against the valve seat of the traveling valve, and the upper part of the upper coupling is connected to the oil pipe thread. The pump barrel is connected to the oil pipe and threaded at the bottom. The top of the pump barrel is tightly fitted with a wear-resistant ring set between the inner ring of the upper coupling and the outer ring of the oil outlet valve. The lower end of the pump barrel is threaded to the middle coupling, and the lower end of the middle coupling is connected to the connecting pipe. The lower end of the connecting pipe is connected to the pressure reducing valve through the lower coupling. The pressure reducing valve is threaded to the fixed valve connector. The inner surface of the pump barrel is coated with nickel carbide, and the outer surface of the internally threaded plunger is coated with tungsten carbide. The nickel carbide coating and the tungsten carbide coating form a corrosion-resistant friction pair with a potential difference ≤0.3V.

2. The oil pump as described in claim 1, characterized in that, The base material of the pump cylinder is 1Cr5Mo, the wall thickness is 8mm or 10mm or more, and the minimum yield strength of the matrix is ​​70Ksi.

3. The oil pump as described in claim 2 or 3, characterized in that, The base material of the internal threaded plunger is alloy steel, and the surface is coated with tungsten carbide non-metallic ceramic coating; the sand sink groove of the internal threaded plunger is formed by spray welding.

4. The oil pump as described in claim 3, characterized in that, The floating valve and pressure reducing valve assembly adopts a combination of zirconia ceramic valve ball and tungsten carbide valve seat, and the inner hole of the tungsten carbide valve seat is coated with high-density polytetrafluoroethylene material.

5. The oil pump as described in claim 1, characterized in that, The pressure reducing valve assembly consists of two valve covers connected in series, with two ball valves inside. The upper one is a sealing ball valve, and the lower one is a pressure reducing ball valve. The valve ball opening impact position is an inclined surface with a through hole to increase the liquid flow channel area.

6. The oil pump as described in claim 1, characterized in that, It also includes a pump-mounted air-sand anchor, with a fixed valve connector connected to the upper part of the pump-mounted air-sand anchor; the pump-mounted air-sand anchor includes an inlet pipe, a separation pipe, an inlet pipe, a positioning connector, and a sedimentation chamber; the upper part of the inlet pipe is provided with an oblique exhaust hole, and the lower part is provided with an oblique inlet hole, through which liquid can enter the interior; the outer surface of the separation pipe is provided with a spiral blade that surrounds the circumference; the spiral blade is provided with a separation pipe inlet at the bottom; when the liquid enters through the oblique inlet, it is accelerated and divided by the spiral, the sand and gravel are thrown to the outer circle and deposited into the sedimentation chamber, the liquid and gas enter through the separation pipe inlet, the gas rises and is discharged through the oblique exhaust hole, the liquid settles and enters through the lower inlet of the inlet pipe, and rises to reach the oil pump inlet.

7. The oil pump as described in claim 1, characterized in that, The valve cover of the oil inlet valve adopts a guided full-flow valve with internal guide ribs; a wear-resistant ring is added between the upper part of the pump barrel and the coupling.

8. The oil pump as described in claim 1, characterized in that, The length of the internally threaded plunger is greater than the length of the pump barrel.

9. The oil pump as described in claim 1, characterized in that, The oil outlet hole of the oil inlet valve is provided with a through hole.

10. The oil pump as described in claim 1, characterized in that, The pump cylinder wall thickness is 8mm or 10mm or more.

Images