Spring-pressed dilating casing packer

Abstract

This invention discloses a spring-loaded expansion casing plugging device, relating to the technical field of oil well production equipment. It includes an upper connector, an upper retaining ring, a central tube, a lower retaining ring, an upper adjusting spring seat, a spring, a lower spring seat, a soluble retaining ring, an upper casing of the expansion sleeve, an expansion sleeve, a lower casing of the expansion sleeve, a sealing ball, and a lower connector. It is suitable for sealing the annulus in oil wells during backwashing, preventing the washing fluid from entering low-pressure oil layers and contaminating or clogging them. The entire device is simple to manufacture and easy to assemble, minimizing uncertainties and effectively improving the success rate of downhole tools. The small diameter of the expansion sleeve during downhole operation prevents it from scratching the casing wall with burrs, extending its service life. Two unsealing methods are used during uphole operation, reducing the risk of well jamming and providing a longer service life and greater reliability than a rubber cup.

Description

Technical Field

[0001] This invention relates to the field of oil well production equipment technology, and in particular to a spring-loaded expansion casing plug. Background Technology

[0002] Conventional hot washing non-pressurized oil layer devices generally have the following shortcomings:

[0003] The packer with a single-flow valve is designed to seal the casing space. The packer is larger in diameter than the casing. When it is run into the well, it rubs against the casing, which can easily damage the packer's rubber sleeve, resulting in poor sealing and leakage. When the tubing is pulled up, it is easy for it to flip over, reducing the number of well cleaning cycles and resulting in poor reliability.

[0004] The installation method, which involves a drop-out connector, packer, and support tubing, is complex, requiring two runs of tubing. The packer also needs to be pressurized and expanded using a pressure vehicle, and the support tubing further increases construction costs, resulting in a long work cycle and high operating costs. Furthermore, it is prone to sand burial during secondary operations. Summary of the Invention

[0005] The purpose of this invention is to provide a spring-loaded expansion sleeve plug to solve the problems existing in the prior art, and it has the advantages of simple structure and long service life.

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

[0007] This invention provides a spring-loaded expansion sleeve plug, comprising an upper connector, an upper retaining ring, a central tube, a lower retaining ring, an upper adjusting spring seat, a spring, a lower spring seat, a soluble retaining ring, an upper protective sleeve for the expansion sleeve, an expansion sleeve, a lower protective sleeve for the expansion sleeve, a sealing ball, and a lower connector;

[0008] The upper connector is sleeved on the top of the central tube. The top of the upper connector is used to connect to the lower oil pipe of the oil pump. The lower retaining ring is provided at the bottom of the inner wall of the upper connector and the upper retaining ring is provided at the top of the outer wall of the central tube. The outer diameter of the upper retaining ring is smaller than the inner diameter of the upper connector, and the inner diameter of the lower retaining ring is larger than the outer diameter of the central tube. A buffer cavity is formed between the upper retaining ring and the lower retaining ring.

[0009] A liquid-passing slit is formed along the axial direction on the central tube;

[0010] The upper adjusting spring seat is disposed at the bottom of the upper connector and sleeved on the outside of the central tube. The upper adjusting spring seat can adjust its axial position on the central tube. The lower spring seat is disposed below the upper adjusting spring seat and slidably connected to the central tube. The spring is sleeved on the outside of the central tube and disposed between the upper adjusting spring seat and the lower spring seat.

[0011] The soluble retaining ring is disposed at the bottom of the lower spring seat. The top end of the upper protective sleeve of the expansion tube is engaged with the shoulder disposed at the bottom of the lower spring seat. The lower end of the upper protective sleeve of the expansion tube is connected to the top of the expansion tube by a thread. The expansion tube is sleeved on the outside of the central tube. The lower protective sleeve of the expansion tube is disposed at the bottom of the expansion tube sleeve and is connected by a thread. The lower connector is connected to the bottom of the central tube. The bottom of the lower protective sleeve of the expansion tube is sleeved on the lower connector and fixed with a scissor pin. The sealing ball is disposed in the inner cavity of the lower connector and can seal the liquid passage hole of the lower connector.

[0012] Preferably, the upper retaining ring is connected to the central tube by threads and rivets, and the lower retaining ring is connected to the upper connector by threads and rivets.

[0013] Preferably, the upper adjusting spring seat and the central tube are connected by a thread.

[0014] Preferably, the soluble retaining ring is made of a soluble metal.

[0015] Preferably, the soluble retaining ring is threaded to the outside of the central tube.

[0016] Preferably, the bottom end of the lower protective sleeve of the expansion tube is sleeved on the outside of the top outer wall of the lower connector, and the lower protective sleeve of the expansion tube and the lower connector are connected by a sealing shear pin.

[0017] Preferably, a sealing ring is provided at the connection between the lower protective sleeve of the expansion tube and the lower connector.

[0018] Preferably, a baffle plate is provided between the inner cavity of the lower connector and the cavity of the central tube, and the baffle plate is provided with a plurality of liquid passage holes.

[0019] Preferably, a pressure-reducing slit is provided radially on the outer side of the expansion tube, and a pressure-reducing groove is provided on the inner side of the expansion tube.

[0020] The present invention achieves the following technical effects compared to the prior art:

[0021] The spring-loaded expansion casing plugger of this invention is suitable for sealing the annulus of the casing during backwashing in oil well production, preventing the washing fluid from entering the low-pressure oil layer and contaminating or clogging it. The entire device is simple to manufacture and easy to assemble, minimizing uncertainties and effectively improving the success rate of downhole tools. During running-in, the small diameter of the expansion sleeve prevents it from scratching the casing wall with burrs, extending its service life. During lifting, two unsealing methods are used, reducing the risk of well jamming and providing a longer service life and greater reliability than rubber cup plugs. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the elastic expansion oil sleeve plug of the present invention;

[0024] Figure 2 This is a schematic diagram of the working state inside the sleeve in this invention;

[0025] In the diagram: 1. Upper connector; 2. Upper retaining ring; 3. Central tube; 4. Lower retaining ring; 5. Upper adjusting spring seat; 6. Spring; 7. Lower spring seat; 8. Soluble retaining ring; 9. Upper protective sleeve of expansion tube; 10. Expansion tube; 11. Lower protective sleeve of expansion tube; 12. Unsealing shear pin; 13. Ball baffle; 14. Sealing ball; 15. Lower connector; 16. Stabilizing pin; 17. Liquid passage gap; 18. Rubber ring; 19. Sleeve; 20. Oil pipe; 21. Buffer chamber; 22. Sandproof pipe. Detailed Implementation

[0026] 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.

[0027] The purpose of this invention is to provide a spring-loaded expansion sleeve plug to solve the problems existing in the prior art.

[0028] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0029] The spring-loaded expansion sleeve plug in this embodiment, such as Figures 1-2 As shown, it includes an upper connector 1, an upper retaining ring 2, a central tube 3, a lower retaining ring 4, an upper adjusting spring seat 5, a spring 6, a lower spring seat 7, a soluble retaining ring 8, an upper protective sleeve of the expansion tube 9, an expansion tube 10, a lower protective sleeve of the expansion tube 11, a sealing ball 14, and a lower connector 15.

[0030] The upper connector 1 is sleeved on the top of the central tube 3. The top of the upper connector 1 is used to connect the lower oil pipe 20 of the oil pump. The bottom of the inner wall of the upper connector 1 is provided with a lower retaining ring 4, and the top of the outer wall of the central tube 3 is provided with an upper retaining ring 2. The outer diameter of the upper retaining ring 2 is smaller than the inner diameter of the upper connector 1, and the inner diameter of the lower retaining ring 4 is larger than the outer diameter of the central tube 3. A buffer cavity 21 is formed between the upper retaining ring 2 and the lower retaining ring 4.

[0031] A liquid-passing slit 17 is provided along the axial direction on the central tube 3;

[0032] The upper adjusting spring seat 5 is located at the bottom of the upper connector 1 and is sleeved on the outside of the central tube 3. The upper adjusting spring seat 5 can adjust its axial position on the central tube 3. The lower spring seat 7 is located below the upper adjusting spring seat 5 and is slidably connected to the central tube 3. The spring 6 is sleeved on the outside of the central tube 3 and is located between the upper adjusting spring seat 5 and the lower spring seat 7.

[0033] A soluble retaining ring 8 is located at the bottom of the lower spring seat 7. The top of the upper protective sleeve 9 of the expansion tube is engaged with the shoulder at the bottom of the lower spring seat 7. The lower end of the upper protective sleeve 9 of the expansion tube is connected to the top of the expansion tube 10 by a thread. The expansion tube 10 is sleeved on the outside of the central tube 3. The lower protective sleeve 11 of the expansion tube is located at the bottom of the expansion tube 10 and is connected by a thread. The lower connector 15 is connected to the bottom of the central tube 3. The bottom of the lower protective sleeve 11 of the expansion tube is sleeved on the lower connector 15 and fixed with a scissor pin. The sealing ball 14 is located in the inner cavity of the lower connector 15 and can seal the liquid passage of the lower connector 15.

[0034] In this specific embodiment, the upper retaining ring 2 is connected to the central tube 3 by threads and stabilizing pins, and the lower retaining ring 4 is connected to the upper connector 1 by threads and stabilizing pins 16.

[0035] In this specific embodiment, the upper adjusting spring seat 5 and the central tube 3 are connected by a thread.

[0036] In this specific embodiment, the soluble retaining ring 8 is made of soluble metal.

[0037] In this specific embodiment, the soluble retaining ring 8 is threaded to the outside of the central tube 3.

[0038] In this specific embodiment, the bottom end of the lower protective sleeve 11 of the expansion tube is sleeved on the outside of the top outer wall of the lower connector 15, and the lower protective sleeve 11 of the expansion tube and the lower connector 15 are connected by the unsealing shear pin 12.

[0039] In this specific embodiment, a sealing ring 18 is provided at the connection between the lower protective sleeve 11 of the expansion tube and the lower connector 15.

[0040] In this specific embodiment, a ball baffle 13 is provided between the inner cavity of the lower connector 15 and the cavity of the central tube 3, and the ball baffle 13 is provided with a plurality of liquid passage holes.

[0041] In this specific embodiment, a pressure-reducing slit is provided radially on the outer side of the expansion tube 10, and a pressure-reducing groove is provided on the inner side of the expansion tube 10.

[0042] The working principle of the spring-loaded expansion sleeve plug in this invention is as follows:

[0043] The upper connector 1 is threadedly connected to the lower oil pipe 20 of the oil pump, and the lower connector 15 is connected to the sandproof pipe 22.

[0044] The soluble retaining ring 8 presses against the lower spring seat 7, preventing the pre-tightened spring 6 from descending. The upper spring seat 6 is adjusted according to the compression distance to keep the diameter of the expansion sleeve 10 constant. After the device has been in the oil well for a period of time, the underground oil and water impact the soluble retaining ring 8 through the fluid passage 17 on the central pipe 3, causing the threads on the soluble retaining ring 8 to dissolve. When the elastic force of the spring 6 is greater than the resistance of the soluble retaining ring 8, the spring 6 pushes the lower spring seat 7, the soluble retaining ring 8, and the upper protective sleeve 9 of the expansion sleeve to compress the expansion sleeve 10, causing the expansion sleeve 10 to expand and seal against the wall of the casing 19, sealing the annulus.

[0045] After a period of production, wax buildup in the tubing 20 of an oil well reduces oil production, necessitating backwashing. When the washing fluid descends through the annulus, the expansion sleeve 10, sealing the casing wall, prevents the fluid from entering through the fluid passage 17 on the central tube 3. The descending fluid is blocked by the sealing ball 14, and the fluid only returns to the surface via the central tube 3 and tubing 20. This prevents the washing fluid from entering the formation, protecting the oil layer from contamination and blockage. During pumping, the washing fluid does not need to be extracted from the oil layer, achieving energy savings.

[0046] During oil extraction, the up and down strokes cause the downhole tubing to move up and down. The upper retaining ring 2 and the lower retaining ring 4 of this device have a certain space. When the pressure diffuser 10 of this device is attached to the casing wall, only the upper connector 1 moves up and down during oil extraction, while the part below the central tube 3 remains stationary, thus increasing the service life of the pressure diffuser 10.

[0047] When the downhole tubing is pulled out during the next operation, the lower retaining ring 4 on the upper connector 1 moves upward and rests against the upper retaining ring 2 on the central tube 3, bringing out the pressure diffuser 10 and releasing it. If the pressure diffuser 10 cannot be pulled out smoothly, when a certain load is reached, the release shear pin 12 cuts the lower casing 11 of the pressure diffuser and moves downward, causing the spring 6 to straighten, the pressure diffuser 10 to return to its original diameter, and the tubing is pulled out smoothly.

[0048] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A spring-loaded expansion sleeve plug, characterized in that: It includes an upper connector, an upper retaining ring, a central tube, a lower retaining ring, an upper adjusting spring seat, a spring, a lower spring seat, a soluble retaining ring, an upper protective sleeve for the expansion tube, an expansion tube, a lower protective sleeve for the expansion tube, a sealing ball, and a lower connector; The upper connector is sleeved on the top of the central tube. The top of the upper connector is used to connect to the lower oil pipe of the oil pump. The lower retaining ring is provided at the bottom of the inner wall of the upper connector and the upper retaining ring is provided at the top of the outer wall of the central tube. The outer diameter of the upper retaining ring is smaller than the inner diameter of the upper connector, and the inner diameter of the lower retaining ring is larger than the outer diameter of the central tube. A buffer cavity is formed between the upper retaining ring and the lower retaining ring. A liquid-passing slit is formed along the axial direction on the central tube; The upper adjusting spring seat is disposed at the bottom of the upper connector and sleeved on the outside of the central tube. The upper adjusting spring seat can adjust its axial position on the central tube. The lower spring seat is disposed below the upper adjusting spring seat and slidably connected to the central tube. The spring is sleeved on the outside of the central tube and disposed between the upper adjusting spring seat and the lower spring seat. The soluble retaining ring is disposed at the bottom of the lower spring seat. The top end of the upper protective sleeve of the expansion tube is engaged with the shoulder disposed at the bottom of the lower spring seat. The lower end of the upper protective sleeve of the expansion tube is connected to the top of the expansion tube by a thread. The expansion tube is disposed outside the central tube. The lower protective sleeve of the expansion tube is disposed at the bottom of the expansion tube and is connected by a thread. The lower connector is connected to the bottom of the central tube. The bottom of the lower protective sleeve of the expansion tube is fitted onto the lower connector and fixed with a scissor pin. The sealing ball is disposed in the inner cavity of the lower connector and can seal the liquid passage hole of the lower connector.

2. The spring-loaded expansion sleeve plugging device according to claim 1, characterized in that: The upper retaining ring is connected to the central tube by threads and rivets, and the lower retaining ring is connected to the upper connector by threads and rivets.

3. The spring-loaded expansion sleeve plugging device according to claim 1, characterized in that: The upper adjusting spring seat is connected to the central tube by a thread.

4. The spring-loaded expansion sleeve plugging device according to claim 1, characterized in that: The soluble retaining ring is made of soluble metal.

5. The spring-loaded expansion sleeve plugging device according to claim 1, characterized in that: The soluble retaining ring is threaded to the outside of the central tube.

6. The spring-loaded expansion sleeve plugging device according to claim 1, characterized in that: The bottom end of the lower protective sleeve of the expansion tube is sleeved on the outside of the top outer wall of the lower connector, and the lower protective sleeve of the expansion tube and the lower connector are connected by shear pins.

7. The spring-loaded expansion sleeve plugging device according to claim 1, characterized in that: A sealing ring is provided at the connection between the lower protective sleeve of the expansion tube and the lower connector.

8. The spring-loaded expansion sleeve plugging device according to claim 1, characterized in that: A baffle plate is provided between the inner cavity of the lower connector and the cavity of the central tube, and the baffle plate is provided with a plurality of liquid passage holes.

9. The spring-loaded expansion sleeve plugging device according to claim 1, characterized in that: The outer side of the expansion tube is provided with a pressure-reducing slit along the radial direction, and the inner side of the expansion tube is provided with a pressure-reducing groove.

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