A positive circulation constant pressure control valve

Abstract

This invention discloses a positive circulation constant pressure control valve, comprising a central tube, one end of which is fixedly connected to an upper positioning sleeve, the other end of which is fixedly connected to an upper connector, and the other end of which is fixedly connected to a lower positioning sleeve, the other end of which is fixedly connected to a lower connector. A well-washing piston is embedded and fixedly mounted on the inner wall of the upper positioning sleeve. The well-washing piston has a through hole, an annular groove, and an annular cavity on its inner wall. An annular rack is slidably connected to the inner wall of the annular cavity. This invention, through the use of a piezoelectric sensor, a conductive spring, and a triangular plate, allows well-washing fluid to enter the central tube through an oil pipe. When the well-washing pressure reaches a set value, the control valve opens, allowing the well-washing fluid to flow through the through hole and return to the surface through a discharge hole. This results in low well-washing fluid consumption and minimal contamination of the oil reservoir.

Description

Technical Field

[0001] This invention relates to the field of control valve technology, and in particular to a positive circulation constant pressure control valve. Background Technology

[0002] Wax prevention and removal in oil wells are aimed at preventing wax buildup on the tubing walls and near the well bottom to ensure normal oil well production. Crude oil contains varying amounts of paraffin wax, which is generally in a dissolved state under reservoir conditions. As crude oil rises from the well bottom and flows through the tubing, the temperature and pressure gradually decrease, causing the wax to precipitate, accumulate, and adhere to the tubing walls—a phenomenon known as well wax deposition. This reduces the tubing's inner diameter, affecting the well's production capacity and, in severe cases, causing the well to shut down.

[0003] In oilfield mechanical production wells, wax buildup can increase energy consumption and even affect operational efficiency. Regular hot washing to remove the wax is commonly used. Current conventional hot washing often employs reverse circulation, where the washing fluid enters the wellbore through the casing and returns to the surface via the pump and tubing. This method has low thermal efficiency, consumes large volumes of fluid, and the washing fluid can easily enter the formation, causing significant damage to the oil reservoir. The cycle for the well to return to normal production is long, impacting oil well output.

[0004] Therefore, we designed a positive circulation constant pressure control valve. Summary of the Invention

[0005] The purpose of this invention is to solve the problems existing in the prior art by proposing a positive circulation constant pressure control valve.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A positive circulation constant pressure control valve includes a central tube. One end of the central tube is fixedly connected to an upper positioning sleeve, and the other end of the upper positioning sleeve is fixedly connected to an upper connector. The other end of the central tube is fixedly connected to a lower positioning sleeve, and the other end of the lower positioning sleeve is fixedly connected to a lower connector. A well-washing piston is embedded and fixedly mounted on the inner wall of the upper positioning sleeve. The well-washing piston has a through hole, an annular groove, and an annular cavity. An annular rack is slidably connected to the inner wall of the annular cavity. Multiple rotating shafts are evenly distributed and rotatably connected to the inner wall of the annular cavity, and each rotating shaft is fixedly connected to a side wall of... The device includes gears, and multiple sliding cavities are evenly distributed on the inner wall of the annular cavity. Each sliding cavity has a sliding plate that is sealed and slidably connected to its inner wall. Each sliding plate has a rack that is fixedly connected to its inner wall. The rack is slidably connected through the inner wall of the annular cavity. A triangular plate is fixedly connected to the end of the rack away from the sliding plate. The inner wall of the well-washing piston has an arc-shaped cavity. A sliding plug is sealed and slidably connected to the inner wall of the arc-shaped cavity. The arc-shaped cavity is fixedly connected to the sliding cavity through a connecting pipe. A conductive spring is fixedly connected to the side wall of the sliding plug. The other end of the conductive spring is fixedly connected to the inner wall of the arc-shaped cavity. The lower positioning sleeve has a trigger mechanism that supplies power to the conductive spring.

[0008] Furthermore, the triggering mechanism includes a piezoelectric sensor fixedly connected to the inner wall of the lower positioning sleeve, a constant pressure piston slidably connected inside the central tube, a pressure block fixedly connected to the side wall of the constant pressure piston, a first spring fixedly connected to the side wall of the lower positioning sleeve, the other end of the first spring being fixedly connected to the constant pressure piston, and the piezoelectric sensor and the conductive spring being electrically connected.

[0009] Furthermore, the inner wall of the well-washing piston is provided with a liquid storage chamber, which is filled with a cleaning agent.

[0010] Furthermore, the well-washing piston has a pumping chamber on its inner wall, and a piston plate is slidably connected inside the pumping chamber. An arc-shaped rod is fixedly connected to the other end of the piston plate.

[0011] Furthermore, the end of the arc-shaped rod away from the piston plate passes through the inner wall of the liquid extraction chamber and is fixedly connected to the side wall of the sliding plug. The inner wall of the liquid extraction chamber is fixedly connected to the liquid storage chamber through a one-way liquid inlet pipe.

[0012] Furthermore, the inner wall of the central tube is provided with multiple spray holes, which are fixedly connected to the liquid extraction chamber through a one-way liquid outlet pipe.

[0013] Furthermore, a rectangular cavity is formed on the inner wall of the upper positioning sleeve, an electric push rod is installed on the inner wall of the rectangular cavity, a connecting rod is fixedly connected to the movable end of the electric push rod, and a sealing sleeve is fixedly connected to the end of the connecting rod away from the electric push rod after passing through the inner wall of the rectangular cavity.

[0014] Furthermore, the inner wall of the central tube has an inlet hole, the inner wall of the upper positioning sleeve has an outlet hole, the sealing sleeve and the side wall of the central tube are fitted together in a sealing and sliding manner, and the triangular plate and the inner wall of the arc groove are fitted together in a sealing and sliding manner.

[0015] Furthermore, each of the gears is meshed with a ring rack, and each of the gears is meshed with a corresponding rack.

[0016] The present invention has the following advantages:

[0017] 1. By setting up structures such as piezoelectric sensors, conductive springs, and triangular plates, the well-washing fluid enters the interior of the central tube through the oil pipe. When the well-washing pressure reaches the set value, the control valve opens, allowing the well-washing fluid to flow through the through hole. The well-washing fluid can also return to the surface through the discharge hole. The forward circulation has higher thermal efficiency than the reverse circulation well-washing, uses less well-washing fluid, causes less pollution to the oil layer, effectively reduces the drainage time after well-washing, and results in better well-washing quality.

[0018] 2. By setting up structures such as a pumping chamber, an arc-shaped rod, and nozzles, the piston plate can also squeeze the cleaning agent inside the pumping chamber to multiple nozzles during the above process, thereby cleaning the inside of the central tube of this control valve and preventing impurities in the well washing fluid from remaining inside the central tube and affecting the use of this control valve.

[0019] 3. The present invention relates to a positive circulation constant pressure control valve for hot washing and wax removal of oil wells. It is connected to the tubing at a predetermined depth of the production tubing string. During hot washing and wax removal, a positive circulation method is adopted. The washing fluid enters through the tubing. When the washing pressure reaches the set value, the positive circulation constant pressure control valve opens, and the washing fluid returns to the surface through the casing. The positive circulation method has higher thermal efficiency than the reverse circulation method, uses less washing fluid, causes less pollution to the oil layer, effectively reduces the drainage time after washing, and results in better washing quality. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of a positive circulation constant pressure control valve proposed in this invention;

[0021] Figure 2 This is a schematic diagram of the internal structure of the well-washing piston in a positive circulation constant pressure control valve proposed in this invention;

[0022] Figure 3 for Figure 2 An enlarged schematic diagram of the structure of part A in the middle.

[0023] In the diagram: 1. Central tube, 2. Upper positioning sleeve, 3. Upper connector, 4. Lower positioning sleeve, 5. Lower connector, 6. Piezoelectric sensor, 7. Constant pressure piston, 8. Well washing piston, 9. Annular cavity, 10. Annular groove, 11. Through hole, 12. Annular rack, 13. Rotating shaft, 14. Gear, 15. Sliding cavity, 16. Slide plate, 17. Rack, 18. Triangular plate, 19. Rectangular cavity, 20. Electric push rod, 21. Arc-shaped cavity, 22. Sealing sleeve, 23. Inlet hole, 24. Pressure block, 25. First spring, 27. Discharge hole, 29. Sliding plug, 30. Conductive spring, 32. Liquid extraction cavity, 33. Piston plate, 34. Arc-shaped rod, 35. Liquid storage cavity, 36. Spray hole. Detailed Implementation

[0024] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0025] Reference Figure 1-3 A positive circulation constant pressure control valve includes a central pipe 1. One end of the central pipe 1 is fixedly connected to an upper positioning sleeve 2, and the other end of the upper positioning sleeve 2 is fixedly connected to an upper connector 3. The other end of the central pipe 1 is fixedly connected to a lower positioning sleeve 4, and the other end of the lower positioning sleeve 4 is fixedly connected to a lower connector 5. A well-washing piston 8 is embedded and fixedly mounted on the inner wall of the upper positioning sleeve 2. The well-washing piston 8 has a through hole 11, an annular groove 10, and an annular cavity 9. An annular rack 12 is slidably connected to the inner wall of the annular cavity 9. Multiple rotating shafts 13 are evenly distributed and rotatably connected to the inner wall of the annular cavity 9. A gear 14 is fixedly connected to the side wall of each rotating shaft 13. Multiple sliding cavities are evenly distributed on the inner wall of the annular cavity 9. 15. Each sliding cavity 15 has a sliding plate 16 sealed and slidably connected to its inner wall. Each sliding plate 16 has a rack 17 fixedly connected to its inner wall. The rack 17 is slidably connected to the inner wall of the annular cavity 9. A triangular plate 18 is fixedly connected to the end of the rack 17 away from the sliding plate 16. After multiple triangular plates 18 come into contact with each other, they can cover the through hole 11. The inner wall of the well washing piston 8 has an arc-shaped cavity 21. The inner wall of the arc-shaped cavity 21 is sealed and slidably connected to a plug 29. The arc-shaped cavity 21 is fixedly connected to the sliding cavity 15 through a connecting pipe. A conductive spring 30 is fixedly connected to the side wall of the plug 29. The other end of the conductive spring 30 is fixedly connected to the inner wall of the arc-shaped cavity 21. The lower positioning sleeve 4 has a trigger mechanism that supplies power to the conductive spring 30.

[0026] The triggering mechanism includes a piezoelectric sensor 6 fixedly connected to the inner wall of the lower positioning sleeve 4. The piezoelectric sensor 6 is existing technology. A constant pressure piston 7 is slidably connected inside the central tube 1. A pressure block 24 is fixedly connected to the side wall of the constant pressure piston 7. A first spring 25 is fixedly connected to the side wall of the lower positioning sleeve 4. The other end of the first spring 25 is fixedly connected to the constant pressure piston 7. The piezoelectric sensor 6 and the conductive spring 30 are electrically connected, and a resistor is provided in the circuit formed by the piezoelectric sensor 6 and the conductive spring 30.

[0027] The well-washing piston 8 has a liquid storage chamber 35 on its inner wall, which is filled with cleaning agent. The inner wall of the liquid storage chamber 35 is equipped with a liquid addition valve cover to facilitate the addition of cleaning agent.

[0028] The well-washing piston 8 has a pumping chamber 32 on its inner wall. A piston plate 33 is slidably connected inside the pumping chamber 32, and an arc rod 34 is fixedly connected to the other end of the piston plate 33.

[0029] The end of the arc-shaped rod 34 away from the piston plate 33 passes through the inner wall of the liquid extraction chamber 32 and is fixedly connected to the side wall of the sliding plug 29. The inner wall of the liquid extraction chamber 32 is fixedly connected to the liquid storage chamber 35 through a one-way liquid inlet pipe. The one-way liquid inlet pipe only allows the cleaning agent inside the liquid storage chamber 35 to be drawn into the liquid extraction chamber 32.

[0030] The inner wall of the central tube 1 is provided with multiple spray holes 36. The spray holes 36 are fixedly connected to the liquid extraction chamber 32 through a one-way liquid outlet pipe. The one-way liquid outlet pipe only allows the cleaning agent inside the liquid extraction chamber 32 to be squeezed out of the spray holes 36.

[0031] The upper positioning sleeve 2 has a rectangular cavity 19 on its inner wall. An electric push rod 20 is installed on the inner wall of the rectangular cavity 19. A connecting rod is fixedly connected to the movable end of the electric push rod 20. The end of the connecting rod away from the electric push rod 20 passes through the inner wall of the rectangular cavity 19 and is fixedly connected to a sealing sleeve 22.

[0032] The inner wall of the central tube 1 has an inlet hole 23, and the inner wall of the upper positioning sleeve 2 has an outlet hole 27. The sealing sleeve 22 and the side wall of the central tube 1 are fitted together and slid together in a sealing manner. The triangular plate 18 and the inner wall of the annular groove 10 are fitted together and slid together in a sealing manner. The sealing sleeve 22 covers and seals the inlet hole 23.

[0033] Each gear 14 is meshed with an annular rack 12, and each gear 14 is meshed with a corresponding rack 17. The annular rack 12 and the rack 17 are staggered.

[0034] In this invention, when using this device, the electric push rod 20 is first activated. The movable end of the electric push rod 20 drives the connecting rod to move, which in turn drives the sealing sleeve 22 away from the inlet hole 23. The well-washing fluid enters the interior of the central tube 1 through the inlet hole 23. Under the injection pressure of the well-washing fluid, the constant pressure piston 7 is pushed to slide to the right a certain distance. The constant pressure piston 7 drives the pressure block 24 to move synchronously until the end of the pressure block 24 away from the constant pressure piston 7 comes into contact with the piezoelectric sensor 6. After the piezoelectric sensor 6 is subjected to a certain compressive force, it supplies power to the conductive spring 30 under the action of the piezoelectric effect. As a result, the conductive spring 30 is energized and contracts. When the conductive spring 30 is energized, it is equivalent to an energized solenoid. Each turn of the spring is equivalent to a circular current, and the current in each turn of the spring is in the same direction. According to the mutual attraction between currents in the same direction, each turn of the spring attracts the adjacent springs. As a result, the conductive spring 30 will contract as a whole. The conductive spring 30 will drive the slide plug 29 to slide to the left a certain distance. The slide cavity 15 is filled with hydraulic oil, so the slide plug 29 drives the slide plate 16 to slide a certain distance through the hydraulic oil. Then the slide plate 16 drives the rack 17 to move. The rack 17 drives the corresponding triangular plate 18 to slide a certain distance away from the through hole 11. At this time, the multiple triangular plates 18 no longer limit the through hole 11. The well washing fluid flows through the through hole 11 and then is discharged through the discharge hole 27.

[0035] Furthermore, during the sliding of the slid plug 29, the piston plate 33 will move synchronously through the arc rod 34, so that the piston plate 33 draws the cleaning agent inside the liquid storage chamber 35 into the liquid extraction chamber 32. The inner wall of the liquid storage chamber 35 is provided with one-way micropores.

[0036] When the well-washing operation is stopped, the well-washing fluid will no longer flow inside the central pipe 1.

[0037] When the pressure inside the central tube 1 decreases, the constant pressure piston 7 will slide to the left and in the opposite direction under the action of the first spring 25, causing the pressure block 24 and the piezoelectric sensor 6 to disengage. Then the conductive spring 30 will stop being energized and will extend due to de-energization. Consequently, the slide plug 29 will slide in the opposite direction to seal, causing the slide plate 16 to drive the corresponding rack 17 to slide in the opposite direction. The rack 17 will drive the corresponding triangular plate 18 to move in the opposite direction. Multiple triangular plates 18 will come into contact with each other, thereby covering the through hole 11.

[0038] During the above process, the sliding plug 29 will also drive the piston plate 33 to move synchronously through the arc rod 34. Then the piston plate 33 will squeeze the cleaning agent inside the pumping chamber 32 to be sprayed out through multiple nozzles 36, thereby cleaning the inside of the central tube 1 and preventing impurities in the well washing fluid from remaining inside the central tube 1 and affecting the use of this control valve.

[0039] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A positive circulation constant pressure control valve, comprising a central pipe (1), characterized in that, One end of the central tube (1) is fixedly connected to an upper positioning sleeve (2), the other end of the upper positioning sleeve (2) is fixedly connected to an upper connector (3), the other end of the central tube (1) is fixedly connected to a lower positioning sleeve (4), and the other end of the lower positioning sleeve (4) is fixedly connected to a lower connector (5). The upper positioning sleeve (2) has a well-washing piston (8) embedded and fixedly installed on its inner wall. The well-washing piston (8) has a through hole (11) on its inner wall, an annular groove (10) on its inner wall, and an annular cavity (9) on its inner wall. An annular rack (12) is slidably connected to the inner wall of the annular cavity (9). Multiple rotating shafts (13) are evenly distributed and rotatably connected to the inner wall of the annular cavity (9). A gear (14) is fixedly connected to the side wall of each rotating shaft (13). Multiple sliding cavities (15) are evenly distributed and opened to the inner wall of each sliding cavity (15). A sliding plate (16) is sealed and slidably connected to the inner wall of each sliding plate (16). A rack (17) is fixedly connected to the inner wall of each sliding plate (16). The rack (17) is slidably connected through the inner wall of the annular cavity (9). A triangular plate (18) is fixedly connected to the end of the rack (17) away from the sliding plate (16). The well-washing piston (8) has an arc-shaped cavity (21) on its inner wall. The inner wall of the arc-shaped cavity (21) is sealed and slidably connected to a sliding plug (29). The arc-shaped cavity (21) is fixedly connected to the sliding cavity (15) through a connecting pipe. A conductive spring (30) is fixedly connected to the side wall of the sliding plug (29). The other end of the conductive spring (30) is fixedly connected to the inner wall of the arc-shaped cavity (21). The lower positioning sleeve (4) is provided with a triggering mechanism that supplies power to the conductive spring (30). The triggering mechanism includes a piezoelectric sensor (6) fixedly connected to the inner wall of the lower positioning sleeve (4). A constant pressure piston (7) is slidably connected inside the central tube (1). A pressure block (24) is fixedly connected to the side wall of the constant pressure piston (7). A first spring (25) is fixedly connected to the side wall of the lower positioning sleeve (4). The other end of the first spring (25) is fixedly connected to the constant pressure piston (7). The piezoelectric sensor (6) and the conductive spring (30) are electrically connected. The well-washing piston (8) has a liquid storage chamber (35) on its inner wall, and the liquid storage chamber (35) is filled with cleaning agent. The well-washing piston (8) has a pumping chamber (32) on its inner wall. A piston plate (33) is slidably connected inside the pumping chamber (32). An arc rod (34) is fixedly connected to the other end of the piston plate (33). Each of the gears (14) is meshed with an annular rack (12), and each of the gears (14) is meshed with a corresponding rack (17).

2. The positive circulation constant pressure control valve according to claim 1, characterized in that, The end of the arc-shaped rod (34) away from the piston plate (33) passes through the inner wall of the liquid extraction chamber (32) and is fixedly connected to the side wall of the sliding plug (29). The inner wall of the liquid extraction chamber (32) is fixedly connected to the liquid storage chamber (35) through a one-way liquid inlet pipe.

3. The positive circulation constant pressure control valve according to claim 2, characterized in that, The inner wall of the central tube (1) is provided with multiple spray holes (36), and the spray holes (36) are fixedly connected to the liquid extraction chamber (32) through a one-way liquid outlet pipe.

4. The positive circulation constant pressure control valve according to claim 1, characterized in that, The upper positioning sleeve (2) has a rectangular cavity (19) on its inner wall. An electric push rod (20) is installed on the inner wall of the rectangular cavity (19). A connecting rod is fixedly connected to the movable end of the electric push rod (20). A sealing sleeve (22) is fixedly connected to the end of the connecting rod away from the electric push rod (20) after passing through the inner wall of the rectangular cavity (19).

5. A positive circulation constant pressure control valve according to claim 4, characterized in that, The inner wall of the central tube (1) is provided with an inlet hole (23), the inner wall of the upper positioning sleeve (2) is provided with an outlet hole (27), the sealing sleeve (22) and the side wall of the central tube (1) are fitted together and slide in a sealed manner, and the triangular plate (18) and the inner wall of the annular groove (10) are fitted together and slide in a sealed manner.

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