Scale blocking assembly and control system of multistage soft sealing plunger pump of oil pumping unit
By designing a multi-stage soft seal structure and a sand settling section in the plunger pump, combined with nitrogen cleaning, the problem of easy jamming in conventional plunger pumps has been solved, achieving long-term scale prevention, reducing maintenance costs, and improving production efficiency.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- OOO TSINDAO SINSHEN NEFTIANOE MASHINOSTROENIE
- Filing Date
- 2026-01-20
- Publication Date
- 2026-04-10
AI Technical Summary
Conventional plunger pumps are prone to jamming in oil wells with high sand content or easy scaling. Existing anti-scaling measures cannot effectively prevent impurities from entering the pump barrel, and the cleaning mechanism is complicated or costly. Traditional scale-blocking devices have limited capacity and are prone to failure.
A multi-stage soft-seal plunger pump is designed, comprising a flow-through scale-blocking assembly, a sand-collecting section, and an air-injection mechanism. It removes deposits by injecting gases such as nitrogen during the upstroke of the plunger pump and prevents scale and sand particles from entering the pump barrel during the downstroke. It also prevents scale formation by combining with a polymer anti-scaling material.
It effectively prevents scale and sand particles from entering the pump barrel, reduces the frequency of pump jamming, extends the pump inspection cycle, achieves long-term protection and reduces maintenance costs, avoids gas corrosion, and improves production efficiency.
Smart Images
Figure CN121828183A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of oil well development technology, specifically to a scale-blocking component and control system for a multi-stage soft-seal plunger pump for an oil pumping unit. Background Technology
[0002] In the oil extraction field, rod pump oil production systems (especially conventional plunger pumps) have long faced the problem of pump jamming. For oil wells with high sand content in the produced fluid or prone to scaling, sand particles and scale continuously accumulate and compact in the tiny gaps between the pump barrel and the plunger, easily leading to pump jamming accidents, causing frequent pump inspections, severely restricting production uptime, and significantly increasing maintenance costs. Traditional solutions mainly fall into two categories: one is to start with materials and processes, such as using high-hardness coatings, optimizing fit clearances, or applying sand control pumps, aiming to enhance the pump's own wear resistance and flow capacity. However, this cannot prevent impurities from entering the pump barrel, which is the fundamental problem. Moreover, when pumping is temporarily stopped, sand particles suspended in the upper tubing column will quickly settle due to the loss of upward fluid flow, and can fall directly into the pump barrel, causing "settling and pump jamming"; the other is to use chemical scale prevention or downhole separation technologies, such as adding inhibitors or installing cyclone desanders. These methods either have problems such as high reagent costs and unstable effects, or are difficult to popularize in conventional tubing strings due to their complex structure and high installation space requirements.
[0003] Furthermore, simply setting up a scale-blocking device to intercept and temporarily store sand and scale is insufficient to achieve long-term protection, because the capacity of the container for collecting sediment is ultimately limited. If sediment is allowed to accumulate continuously, it will eventually overflow, and impurities will bypass the scale-blocking device and enter the pump cylinder below, causing the protective structure to fail or even becoming a new source of pump jamming risk. Therefore, a cleaning mechanism is also needed. In oil pumps, a common operation is gas injection. Although inert gases such as nitrogen can be used for injection, there will inevitably be a small amount of harmful gases such as oxygen in the gas, which may corrode the plunger pump and sucker rod. Summary of the Invention
[0004] To address the aforementioned problems, this invention provides a scale-blocking component for a multi-stage soft-seal plunger pump in an oil pumping unit. The applicable well conditions are as follows: downhole temperature not exceeding 120°C, well fluid viscosity not exceeding 200 mPa•s, free from corrosive media such as hydrogen sulfide and carbon dioxide, containing less than 2000 PPM of calcium and magnesium ions, less than 1000 PPM of salt content, and well inclination less than 15°.
[0005] Specifically, it includes a multi-stage soft-seal plunger installed inside the plunger pump barrel. The multi-stage soft-seal plunger is connected to the disconnector assembly via a central tie rod. A fixed valve cover assembly is installed at the lower end of the pump barrel, and the upper end of the pump barrel is connected to the flow-through scale-blocking assembly via an upper pump barrel coupling. The central tie rod passes through the flow-through scale-blocking assembly and is connected to the disconnector assembly via a smooth rod reducing coupling. The flow-through scale-blocking assembly is connected to the extension tube via an oil pipe reducing coupling, and the disconnector assembly is located in the extension tube. A release structure is connected to the upper end of the extension tube, and a protective cap is installed at the end of the release structure. A scale-blocking cap is installed in the fixed valve cover assembly. An anti-scaling filter is installed in the valve seat of the traveling valve of the multi-stage soft-seal plunger. A guide hole is opened on the valve cover of the traveling valve to reduce turbulence. The flow-through scale-blocking assembly includes a baffle, a sand settling section, and an air filling mechanism.
[0006] Furthermore, an annular cavity is formed between the cylinder of the flow-through scale-blocking assembly and the central tie rod. A sand-collecting section is fixedly provided on the cylinder within the annular cavity. A second sand-collecting section is provided at a symmetrical position relative to the central tie rod. A stop block and a second stop block are fixedly provided on the cylinder above the channel formed between the sand-collecting section and the second sand-collecting section. The stop block and the second stop block are symmetrical structures relative to the central tie rod. An air inlet is provided at the bottom of the sand-collecting section and the second sand-collecting section, and an air supply pipe is connected to the air inlet through a one-way valve.
[0007] Furthermore, the upper ends of the first and second blocks are provided with downwardly inclined sand settling surfaces on both sides; during the upstroke of the plunger pump, the oil enters the annular cavity between the cylinder and the central tie rod through the channel; during the downstroke of the plunger pump and when the pump is temporarily stopped, the first and second blocks prevent scale and sand particles in the oil in the annular cavity from falling into the channel; the scale and sand particles slide down along the sand settling surfaces of the first and second blocks and enter the sand settling section and the second dust and sand section.
[0008] Furthermore, gas is injected into the bottom of the sedimentation section and the second sedimentation section through the gas supply pipe and the gas inlet at a fixed period T during the upstroke of the plunger pump; the gas is preferably one of nitrogen, carbon dioxide, and natural gas; the gas carries up the sediment in the sedimentation section and the second sedimentation section and discharges it from the plunger pump with the oil.
[0009] Furthermore, the lower ends of the first and second blocks are provided with drainage surfaces on both sides; the drainage surfaces guide the oil in the channel into the annular cavity between the cylinder and the central tie rod to reduce resistance; the first and second blocks are also provided with fitting parts that fit with the central tie rod to prevent scale and sand particles from falling into the channel from the fitting parts.
[0010] Furthermore, the flow channel surface of the plunger pump is coated with a 0.02-0.04mm high-polymer anti-scaling material, preferably a polytetrafluoroethylene composite material; the multi-stage soft-seal plunger is a soft-surface plunger, and the surface of the sealing rod is treated with wear resistance to improve the plasticity of the plunger surface.
[0011] The control system for the scale-blocking assembly of the multi-stage soft-seal plunger pump of the present invention includes the above-mentioned scale-blocking assembly and performs the following control steps: Step a: The control unit obtains the preset gas injection cycle T from the gas supply pipe and the gas inlet, and sets the gas injection duration. The system resets the gas injection interval timer and begins accumulating running time. ; Step b: The control unit continuously or periodically monitors the pumping unit's operating time. ,when When the predetermined cleaning cycle has been reached, the system enters a waiting state for gas injection trigger and proceeds to the next step. Step c: The control unit reads the position sensor signal of the pumping unit. If it determines that the current stroke is downstroke, the system waits until the upstroke is detected. When it is confirmed that the pumping unit has entered the upstroke, the system issues a command and opens the gas injection valve on the gas supply pipe, and starts the gas injection duration timer at the same time. Step d: The gas injection valve on the gas supply pipe remains open, and high-pressure gas is injected into the bottom of the sedimentation section and the second sedimentation section through the gas supply pipe and the gas inlet. The injection duration continues... When the set value is reached, the control unit issues a command to close the air injection valve; Step e: After closing the gas injection valve, the control unit will run a timer. Reset to zero and begin the next monitoring cycle with a duration of T.
[0012] Furthermore, the preset gas injection cycle T of the gas delivery pipe and gas inlet is determined by obtaining the sand content in the oil at the current stage in the following way. Obtain the effective volume of the receiving cavity of the settling section and the second settling section. ; Calculate the volumetric flow rate of the oil ,in Let f be the pumping volume of the plunger pump in a single stroke, and f be the pump stroke frequency; calculate the mass of sand particles deposited in the sedimentation section per unit time. ,in Settling efficiency of the settling section; calculate the effective holding mass of the settling section. ,in The density of sand particles in the settling section is SF, which is the safety factor, and the air injection cycle is... .
[0013] Furthermore, when the control unit detects a shutdown signal, it immediately records the shutdown event flag and starts the periodic gas injection timer. The counting is paused; when a restart signal is detected, the control unit activates the restart gas injection preparation program while preparing to start the main motor of the pumping unit. The system maintains the shutdown event flag and enters the waiting state for the first upstroke; the main motor of the pumping unit starts, the sucker rod begins to move, and the control unit begins to monitor the stroke phase. If the first stroke is an upstroke, the next gas injection operation is executed immediately. If the first stroke is a downstroke, the system continues to monitor and waits for the start of the first upstroke; when it is confirmed that the pumping unit has entered the first upstroke after restart, the control unit issues a command and opens the gas injection valve, and starts the gas injection duration timer.
[0014] Furthermore, it also includes a reset operation: when the gas injection duration reaches the set value, the control unit closes the gas injection valve and stops gas injection; clears the shutdown event flag; and resets the timer for periodic gas injection. The timer is reset and restarted. The system exits the gas injection preparation program and resumes normal operation and monitoring, including the periodic gas injection control program.
[0015] The beneficial effects of this invention, compared with the prior art, are that it provides a flow-through scale-blocking assembly at the upper end of the pump barrel and piston assembly. In the annular cavity formed by the cylinder above the pump barrel and the central tie rod, symmetrically arranged baffles with inclined sand-collecting surfaces and sand-collecting parts located below them are provided. During the upstroke of the plunger pump during normal operation, the oil can pass smoothly through the channel formed between the baffles. During the downstroke or more critical temporary shutdown (such as power outage or maintenance), the sand-collecting surface at the upper end of the baffle can effectively block the scale and sand particles that sink in the oil above due to gravity and guide them to the sand-collecting parts on both sides for temporary storage. This can effectively prevent scale, sand particles, etc. from falling into the pump barrel and piston below and causing pump jamming.
[0016] Furthermore, this invention enables periodic gas injection for sand removal, achieving a closed-loop and long-term anti-jamming pump capability. Although the sand settling section can effectively collect sediment, its capacity is limited. Continuously injecting gas into the plunger pump may cause the oxygen and other gases contained in the gas to corrode the plunger pump and sucker rod. This invention, by calculating the gas injection cycle T, injects nitrogen and other gases according to the gas injection cycle and under the interlock control of the upstroke. This can periodically and efficiently agitate the sediment accumulated in the sand settling section and carry it out of the pump with the product fluid flow, restoring its capacity. Thus, the sediment is removed before it overflows and enters the pump barrel below. Attached Figure Description
[0017] Figure 1 This is a schematic diagram of a portion of the multi-stage soft-seal plunger pump for oil pumping units according to the present invention; Figure 2 This is a schematic diagram of another part of the multi-stage soft-seal plunger pump for oil pumping units according to the present invention; Figure 3A This is a schematic diagram of a prior art overcurrent and scale-blocking assembly; Figure 3B This is a structural diagram of the entrance section; Figure 3C This is a schematic diagram of the scale settling section; Figure 3D This is a schematic diagram of the cross-assembly method for the scale-laden sections; Figure 4 This is a schematic diagram of the structure of the flow-through fouling assembly of the present invention; Figure 5 This is a schematic diagram of the flow-through fouling assembly of the present invention from another angle; Figure 6 This is a schematic diagram of the structure of the stop block of the present invention; Figure 7 This is a schematic diagram of the baffle block of the present invention blocking scale and sand particles; Figure 8 This is a control flowchart of the scale-blocking assembly for the multi-stage soft-seal plunger pump of the present invention. Figure 9 This is a flowchart of the process for obtaining the gas injection cycle according to the present invention; In the picture: 1. Flow-through scale-blocking assembly, 11. Cylinder, 12. Baffle, 121. Sand settling surface, 122. Adhesive surface, 123. Second baffle, 120. Sand settling part, 13. Second dust and sand part, 130. Air inlet, 14. Air pipe, 15. Channel, 16. Inlet section 18, scale inlet 181; scale section 19, through hole 191, countersunk hole 192; 2. Tubing reducing coupling, 3. Center tie rod, 4. Protective cap, 5. Release structure, 6. Extension tube, 7. Disconnector assembly, 8. Polished rod reducing coupling, 9. Upper pump barrel coupling, 10. Pump barrel, 10. Multi-stage soft seal plunger, 101. Fixed valve cover assembly. Detailed Implementation The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0018] The existing sand and scale removal assembly installed on the plunger pump includes an inlet section 18 and multiple scale removal sections 19 assembled below the inlet section 18, such as... Figure 3A The inlet section is provided with a scale inlet 181, and the scale-collecting section 19 is provided with two symmetrical through holes 191. Between the two through holes are two symmetrical countersunk holes 192. During assembly, adjacent scale-collecting sections 19 are assembled at a 90-degree angle. Figure 3D Scale and grit in the oil will deposit in the countersink 192 of the scale settling section 19.
[0019] Example 1 The scale-blocking assembly of the multi-stage soft-seal plunger pump for oil pumping units of the present invention includes a multi-stage soft-seal plunger 101 disposed within the pump barrel 10 of the plunger pump. The multi-stage soft-seal plunger 101 is connected to a disconnector assembly 7 via a central tie rod 3. A fixed valve cover assembly 102 is disposed at the lower end of the pump barrel 10, and the upper end of the pump barrel 10 is connected to a flow-through scale-blocking assembly 1 via an upper pump barrel coupling 9. The central tie rod 3 passes through the flow-through scale-blocking assembly 1 and is then connected to the disconnector assembly 7 via a smooth rod reducing coupling 8. The flow-through... The scale-blocking assembly 1 is connected to the extension pipe 6 via the oil pipe reducing coupling 2, and the disconnector assembly 7 is located in the extension pipe 6; the upper end of the extension pipe 6 is connected to the release structure 5, and the end of the release structure 5 is provided with a protective cap 4; the fixed valve cover assembly 102 is provided with a scale-blocking cap, the valve seat of the traveling valve of the multi-stage soft-seal plunger 101 is provided with a scale-preventing filter, and the valve cover of the traveling valve is provided with a guide hole to reduce eddies; the flow-through scale-blocking assembly 1 is provided with a baffle 12, a sand settling section 13 and an air-filling mechanism.
[0020] The cylindrical body 11 of the flow-through scale-blocking assembly 1 forms an annular cavity with the central tie rod 3. A sand-collecting part 13 is fixedly provided on the cylindrical body 11 in the annular cavity. A second sand-collecting part 130 is provided at a symmetrical position relative to the central tie rod 3 of the sand-collecting part 13. A baffle 12 and a second baffle 120 are fixedly provided on the cylindrical body 11 above the channel 16 formed between the sand-collecting part 13 and the second sand-collecting part 130. The baffle 12 and the second baffle 120 are symmetrical structures relative to the central tie rod 3. An air inlet 14 is provided at the bottom of the sand-collecting part 13 and the second sand-collecting part 130. An air supply pipe 15 is connected to the air inlet 14 through a one-way valve.
[0021] The upper ends of the baffle 12 and the second baffle 120 are provided with downwardly inclined sand settling surfaces 121 on both sides; during the upstroke of the plunger pump, the oil enters the annular cavity between the cylinder 11 and the central tie rod 3 through the channel 16; during the downstroke of the plunger pump and when the pump is temporarily stopped, the baffle 12 and the second baffle 120 prevent scale and sand particles in the oil in the annular cavity from falling into the channel 16; the scale and sand particles slide down along the sand settling surfaces 121 of the baffle 12 and the second baffle 120 and enter the sand settling section 13 and the second dust and sand section 130.
[0022] The flow-through scale-blocking assembly 1 of this invention can effectively prevent sand particles and scale from falling into the pump barrel 10 and causing pump jamming. It has a particularly good protective effect against jamming caused by the settling of sand particles and scale during temporary pumping stops such as power outages or stroke adjustments. In addition, except for the pump barrel 10 and the outer surface of the connecting pipe, all the inner and outer surfaces of the plunger pump are coated with a CF anti-scaling coating. The high surface smoothness can effectively prevent the two-electron reaction between calcium and magnesium ions and metal, thereby achieving the purpose of preventing surface scaling.
[0023] Gas is injected into the bottom of the sedimentation section 13 and the second sedimentation section 130 through the gas supply pipe 15 and the air inlet 14 at a fixed gas injection cycle T during the upstroke of the plunger pump; the gas is preferably one of nitrogen, carbon dioxide, and natural gas; the gas carries up the sediment in the sedimentation section 13 and the second sedimentation section 130 and discharges it from the plunger pump with the oil.
[0024] After the sedimentation chamber 13 and the second sedimentation chamber 130 are filled with deposits such as scale and sand, excessive sediment will enter the channels 16 on both sides and fall into the pump barrel 10 below, causing pump jamming. Injecting gas at a fixed cycle can remove the sediment accumulated in the sedimentation chamber while avoiding the injection of excessive gas into the plunger pump, thereby preventing the oxygen and other gases contained in the gas from corroding the plunger pump and sucker rod. At the same time, it can be combined with gas injection oil production, nitrogen huff and puff, and gas injection oil displacement operations to replenish formation energy and displace crude oil, and help solve the problem of insufficient formation pressure.
[0025] The lower ends of the baffle 12 and the second baffle 120 are provided with flow guiding surfaces 122 on both sides; the flow guiding surfaces 122 guide the oil in the channel 16 into the annular cavity between the cylinder 11 and the central tie rod 3 to reduce resistance; the baffle 12 and the second baffle 120 are also provided with fitting parts 123 that fit with the central tie rod 3 to prevent scale and sand particles from falling into the channel 16 from the fitting parts 123.
[0026] The flow channel surface of the plunger pump is coated with a 0.02-0.04mm high-polymer anti-scaling material, preferably polytetrafluoroethylene composite material. This high-polymer anti-scaling material can effectively inhibit the crystallization of substances such as calcium carbonate, magnesium carbonate, barium carbonate, and silicates on the flow channel surface of the oil pump to form scale particles, slowing down or preventing scale particles from clogging the flow channel. This can effectively prevent the occurrence of pump jamming caused by flow channel blockage, thereby extending the pump inspection cycle of the oil pump. The multi-stage soft-seal plunger 101 adopts a soft-surface plunger, and the surface of the sealing rod is treated with wear resistance to improve the plasticity of the plunger surface, which can effectively improve the problem of plunger jamming.
[0027] Example 2 To ensure that deposits in the flow-through fouling assembly 1 are effectively removed, the air injection operation must be limited to the upstroke of the plunger pump. During the upstroke, the oil flows upward from the channel 16, and the injected gas can carry the deposits in the sand settling section 13 out of the pump and into the upper oil pipe by means of the upward liquid flow.
[0028] The control system for the scale-blocking assembly of the multi-stage soft-seal plunger pump for oil pumping units of the present invention includes the following steps: Step a: The control unit obtains the preset gas injection cycle T of the gas supply pipe 15 and the air inlet 14, and sets the gas injection duration. The system resets the gas injection interval timer and begins accumulating running time. ; Step b: The control unit continuously or periodically monitors the pumping unit's operating time. ,when When the predetermined cleaning cycle has been reached, the system enters a waiting state for gas injection trigger and proceeds to the next step. Step c: The control unit reads the position sensor signal of the pumping unit. If it is determined that the current stroke is the downstroke, the system waits until the upstroke is detected. When it is confirmed that the pumping unit has entered the upstroke, the system issues a command and opens the gas injection valve on the gas supply pipe 15, and starts the gas injection duration timer at the same time. In step d, the gas injection valve on the gas supply pipe 15 remains open, and high-pressure gas is injected into the bottom of the sedimentation section 13 and the second sedimentation section 130 through the gas supply pipe 15 and the air inlet 14. The injection duration continues... When the set value is reached, the control unit issues a command to close the air injection valve; Step e: After closing the gas injection valve, the control unit will run a timer. Reset to zero and begin the next monitoring cycle with a duration of T.
[0029] The preset gas injection cycle T of the gas delivery pipe 15 and the air inlet 14 is determined by obtaining the sand content in the oil at the current stage in the following way. To obtain the effective volume of the receiving cavity of the settling section 13 and the second settling section 130. ; Calculate the volumetric flow rate of the oil ,in Let f be the pumping volume of the plunger pump in a single stroke, and f be the pump stroke frequency; calculate the mass of sand particles deposited in the sedimentation section per unit time. ,in The settling efficiency of the sand settling section represents the proportion of sand particles and scale in the flowing oil that are effectively captured and deposited by the sand settling section; the effective holding mass of the sand settling section 13 is calculated. ,in The density of sand particles in the settling section is SF, which is the safety factor, and the air injection cycle is... .
[0030] After the oil pumping unit is shut down due to power outages, maintenance, or parameter adjustments, the settling efficiency of the sand section is... Unlike the settling efficiency during the operation of an oil pumping unit, a large amount of sediment may form in the settling section. Therefore, it is necessary to start the gas injection mechanism to clean the sediment in the settling section separately each time the unit is restarted after a shutdown due to power outage, maintenance or parameter adjustment.
[0031] When the control unit detects a shutdown signal, it immediately records the shutdown event flag and starts the periodic gas injection timer. The counting is paused; when a restart signal is detected, the control unit activates the restart gas injection preparation program while preparing to start the main motor of the pumping unit. The system maintains the shutdown event flag and enters the waiting state for the first upstroke; the main motor of the pumping unit starts, the sucker rod begins to move, and the control unit begins to monitor the stroke phase. Since the crank position is random after shutdown, the first stroke after restart may be an upstroke or a downstroke. If the first stroke is an upstroke, the next gas injection operation is executed immediately. If the first stroke is a downstroke, the system continues to monitor and waits for the start of the first upstroke; when it is confirmed that the pumping unit has entered the first upstroke after restart, the control unit issues a command and opens the gas injection valve, and starts the gas injection duration timer.
[0032] It also includes a reset operation: when the gas injection duration reaches a set value, the control unit closes the gas injection valve and stops gas injection; clears the shutdown event flag; and resets the periodic gas injection running timer. The timer is reset and restarted. The system exits the gas injection preparation program and resumes normal operation and monitoring, including the periodic gas injection control program.
[0033] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.
Claims
1. A scale-blocking assembly for a multi-stage soft-seal plunger pump for an oil pumping unit, comprising a multi-stage soft-seal plunger (101) disposed within the pump barrel (10) of the plunger pump, wherein the multi-stage soft-seal plunger (101) is connected to a disconnector assembly (7) via a central tie rod (3), characterized in that: The lower end of the pump cylinder (10) is provided with a fixed valve cover assembly (102), and the upper end of the pump cylinder (10) is connected to the flow-through scale-blocking assembly (1) through the upper pump cylinder coupling (9). The central tie rod (3) passes through the flow-through and scale-blocking assembly (1) and is connected to the disconnector assembly (7) via the smooth rod reducing coupling (8); The flow-through scale-blocking assembly (1) is connected to the extension pipe (6) via an oil pipe reducing coupling (2), and the disconnector assembly (7) is located in the extension pipe (6); The upper end of the extension tube (6) is connected to the release structure (5), and the end of the release structure (5) is provided with a protective cap (4). The fixed valve cover assembly (102) is provided with a scale-blocking cap, the valve seat of the traveling valve of the multi-stage soft-seal plunger (101) is provided with a scale-proof filter screen, and the valve cover of the traveling valve is provided with a flow guide hole to reduce eddies. The flow-through scale-blocking assembly (1) is provided with a baffle (12), a sand settling section (13) and an aeration mechanism.
2. The scale-blocking assembly of the multi-stage soft-seal plunger pump according to claim 1, characterized in that: The cylinder (11) of the flow-through scale-blocking assembly (1) forms an annular cavity with the central tie rod (3), and a sand settling part (13) is fixedly provided on the cylinder (11) in the annular cavity. A second sand settling section (130) is provided at a position symmetrical to the central tie rod (3) of the sand settling section (13). A stop block (12) and a second stop block (120) are fixedly installed on the cylinder (11) above the channel (16) formed between the sedimentation section (13) and the second sedimentation section (130). The stop (12) and the second stop (120) are symmetrical structures with respect to the central tie rod (3); The bottom of the sedimentation section (13) and the second sedimentation section (130) are provided with an air inlet (14), and the air supply pipe (15) is connected to the air inlet (14) through a one-way valve.
3. The scale-blocking assembly of the multi-stage soft-seal plunger pump according to claim 2, characterized in that: The upper ends of the block (12) and the second block (120) are provided with downwardly inclined sand-collecting surfaces (121) on both sides. During the upstroke of the plunger pump, the oil enters the annular cavity between the cylinder (11) and the central tie rod (3) through the channel (16); During the downstroke and temporary stop of the plunger pump, the stop block (12) and the second stop block (120) prevent scale and sand particles in the oil in the annular cavity from falling into the channel (16). The scale and sand particles slide down the sand settling surface (121) of the first block (12) and the second block (120) and enter the sand settling section (13) and the second dust and sand section (130).
4. The scale-blocking assembly of the multi-stage soft-seal plunger pump according to any one of claims 2 or 3, characterized in that: Gas is injected into the bottom of the sedimentation section (13) and the second sedimentation section (130) through the gas delivery pipe (15) and the air inlet (14) at a fixed period T during the upstroke of the plunger pump. The gas is preferably one of nitrogen, carbon dioxide, and natural gas; The gas carries up the sediment in the sedimentation section (13) and the second sedimentation section (130) and discharges it with the oil from the plunger pump.
5. The scale-blocking assembly of the multi-stage soft-seal plunger pump according to claim 4, characterized in that: The lower ends of the baffle (12) and the second baffle (120) are provided with drainage surfaces (122) on both sides. The drainage surface (122) guides the oil in the channel (16) into the annular cavity between the cylinder (11) and the central tie rod (3) to reduce resistance; The stop block (12) and the second stop block (120) are also provided with a fitting part (123) that fits with the central pull rod (3) to prevent dirt and sand particles from falling into the channel (16) from the fitting part (123).
6. The scale-blocking assembly of the multi-stage soft-seal plunger pump according to claim 5, characterized in that: The flow channel surface of the plunger pump is coated with a 0.02-0.04mm thick polymer anti-scaling material, preferably a polytetrafluoroethylene composite material; The multi-stage soft-seal plunger (101) is a soft-surface plunger, and the surface of the sealing rod is treated with wear resistance to improve the plasticity of the plunger surface.
7. A control system for a scale-blocking assembly of a multi-stage soft-seal plunger pump for an oil pumping unit, comprising the scale-blocking assembly as described in any one of claims 1-6, characterized in that, Perform the following control steps: Step a: The control unit obtains the preset gas injection cycle T of the gas supply pipe (15) and the air inlet (14), and sets the gas injection duration. The system resets the gas injection interval timer and begins accumulating running time. ; Step b: The control unit continuously or periodically monitors the pumping unit's operating time. ,when When the predetermined cleaning cycle has been reached, the system enters a waiting state for gas injection trigger and proceeds to the next step. Step c, the control unit reads the position sensor signal of the pumping unit. If it is determined that the current stroke is the downstroke, the system waits until the upstroke is detected. When it is confirmed that the pumping unit has entered the upstroke, the system issues a command and opens the gas injection valve on the gas supply pipe (15), and starts the gas injection duration timer at the same time. In step d, the gas injection valve on the gas supply pipe (15) remains open, and high-pressure gas is injected into the bottom of the sedimentation section (13) and the second sedimentation section (130) through the gas supply pipe (15) and the air inlet (14). The gas injection duration is... When the set value is reached, the control unit issues a command to close the air injection valve; Step e: After closing the gas injection valve, the control unit will run a timer. Reset to zero and begin the next monitoring cycle with a duration of T.
8. The control system for the scale-blocking assembly according to claim 7, characterized in that: The preset gas injection cycle T of the gas delivery pipe (15) and the gas inlet (14) is determined in the following way: Obtain the sand content in the oil at the current stage. To obtain the effective volume of the receiving cavity of the settling section (13) and the second settling section (130). ; Calculate oil volumetric flow rate ,in denoted as , where is the pumping volume per stroke of the plunger pump, and f is the stroke frequency of the plunger pump. Calculate the mass of sand particles deposited in the sedimentary section per unit time. ,in The settling efficiency of the sedimentation section; Calculate the effective holding mass of the sedimentation section (13) ,in SF is the bulk density of sand particles in the settling section, and SF is the safety factor. The gas injection cycle .
9. The control system for the scale-blocking assembly according to claim 8, characterized in that: When the control unit detects a shutdown signal, it immediately records the shutdown event flag and starts the periodic gas injection timer. Pause counting; When a restart signal is detected, the control unit activates the restart gas injection preparation program while preparing to start the main motor of the pumping unit. The system maintains the shutdown event flag and enters the state of waiting for the first upstroke. When the main motor of the pumping unit starts, the sucker rod begins to move, and the control unit begins to monitor the stroke phase. If the first stroke is the upstroke, the next gas injection operation is executed immediately. If the first stroke is the downstroke, the system continues to monitor and waits for the start of the first upstroke. When it is confirmed that the pumping unit has entered the first upward stroke after restarting, the control unit issues a command and opens the gas injection valve, starting the gas injection duration timer.
10. The control system for the scale-blocking assembly according to claim 9, characterized in that: It also includes a reset operation, whereby the control unit closes the gas injection valve and stops gas injection when the gas injection duration reaches a set value; Clear the shutdown event flag and set the periodic gas injection timer. The timer is reset and restarted. The system exits the gas injection preparation program and resumes normal operation and monitoring, including the periodic gas injection control program.