A downhole bridge plug

Abstract

This invention relates to the field of oil and gas well fracturing technology, specifically disclosing a downhole bridge plug, including a central cylinder. A setting tool is provided on one side of the central cylinder, and a perforating gun is provided on one side of the setting tool. A movable cylinder is provided on the outer wall of the central cylinder, and a first anti-outburst ring is provided on the outer wall of the central cylinder. A first rubber sleeve is fixedly installed at the bottom of the first anti-outburst ring, and a first anti-outburst ring is also provided at the bottom of the first rubber sleeve. A second rubber sleeve is provided on the outer wall of the central cylinder, and a second anti-outburst ring is fixedly installed at both the top and bottom of the second rubber sleeve. This invention can effectively protect the bridge plug body through the protective components, avoiding damage to the bridge plug body caused by burrs protruding from the inner wall of the casing and casing deformation points during tool string advancement, which would lead to sealing failure. At the same time, during sealing, the cover plate is pressed against the inner wall of the casing for support, ensuring the stability of the operation, ensuring the sealing effect, and improving the overall fracturing operation efficiency.

Description

Technical Field

[0001] This invention relates to the field of oil and gas well fracturing technology, and in particular to a downhole bridge plug. Background Technology

[0002] Fracturing, also known as hydraulic fracturing, is a method used in oil or gas production to create fractures in oil and gas reservoirs using hydraulic force. It artificially creates fractures in the formation, improving the underground flow environment for oil and increasing well production. Fracturing plays a crucial role in improving bottomhole flow conditions, mitigating inter-layer flow, and enhancing reservoir dynamics. Fracturing operations in oil wells require the use of fracturing tools, which include downhole tool strings and surface equipment. The downhole tool string includes components such as a perforating gun, bridge plug, and tubing. During fracturing, the tubing is used to pump the perforating gun and bridge plug to a predetermined depth. After isolating the fractured section, the perforating gun is used to detonate perforations in the target section. Finally, sand-carrying fracturing fluid is pumped in to perform fracturing. However, since casing is typically laid in oil wells, and there are usually casing transition points inside the casing, the tool string may scratch the bridge plug sleeve at these transition points. When the tool string is in the anchoring and sealing stage inside the casing, it may experience significant shaking, affecting operational stability. Additionally, at large diameter transition points, the anchoring bridge plug may not be properly anchored. All of these problems can prevent the fracturing operation from proceeding normally, severely impacting the overall fracturing efficiency. Summary of the Invention

[0003] The purpose of this invention is to address the shortcomings of existing technologies by proposing a downhole bridge plug.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: A downhole bridge plug includes a central cylinder, a setting tool is provided on one side of the central cylinder, a perforation gun is provided on one side of the setting tool, a movable cylinder is provided on the outer wall of the central cylinder, a first anti-outburst ring is provided on the outer wall of the central cylinder, a first rubber sleeve is fixedly installed at the bottom of the first anti-outburst ring, a first anti-outburst ring is also provided at the bottom of the first rubber sleeve, a second rubber sleeve is provided on the outer wall of the central cylinder, a second anti-outburst ring is fixedly installed at the top and bottom of the second rubber sleeve, a pressure cylinder is provided on the outer wall of the central cylinder, a bottom cylinder is provided on the outer wall of the central cylinder, an anchoring assembly including a clamping plate is provided between the bottom cylinder and the pressure cylinder, and eight sets of protective assemblies including cover plates are provided on the side of the pressure cylinder away from the central cylinder. The eight sets of clamping plates are slidably installed on the top of the bottom cylinder. An anchor block is fixedly installed on the side of the clamping plate away from the central cylinder. A support rod is provided between the clamping plate and the pressure cylinder. The two ends of the support rod are rotatably connected to the clamping plate and the pressure cylinder, respectively. The cover plate is located on the outside of the first rubber cylinder. An installation plate is fixedly installed on the side wall of the pressure cylinder away from the central cylinder. A movable plate is slidably installed on the installation plate. A connecting plate is rotatably installed on the movable plate. The cover plate is fixedly installed on the connecting plate.

[0005] Preferably, the movable cylinder is slidably mounted on the central cylinder, the first anti-protrusion ring is disposed on the lower side of the movable cylinder, the top of the first anti-protrusion ring is in contact with the bottom of the movable cylinder, the contact surfaces of the movable cylinder and the first anti-protrusion ring are both wedge-shaped surfaces, and the first anti-protrusion rings on both the top and bottom sides of the first rubber cylinder are movably mounted on the outer wall of the central cylinder.

[0006] Preferably, the second rubber sleeve is disposed below the first rubber sleeve, and both the second rubber sleeve and the second anti-protrusion ring are movably mounted on the outer wall of the central cylinder, with the contact surface between the second anti-protrusion ring and the first anti-protrusion ring being a wedge-shaped surface.

[0007] Preferably, the pressure cylinder is movably mounted on the central cylinder, the top and bottom of the pressure cylinder are both wedge-shaped surfaces, the side of the clamping plate near the pressure cylinder is a wedge-shaped surface, and a fourth pin is provided between the pressure cylinder and the central cylinder, and the pressure cylinder is connected and fixed to the central cylinder by the fourth pin.

[0008] Preferably, a second pin is provided between the movable plate and the mounting plate, and the movable plate is connected and fixed to the mounting plate by the second pin.

[0009] Preferably, the protective assembly further includes a crackable plate, which is fixedly installed on the side of the connecting plate near the movable plate, and the crackable plate is rotatably connected to the movable plate via a rotating shaft.

[0010] Preferably, a third pin is provided between the movable plate and the rotating shaft, and the rotating shaft is connected and fixed to the movable plate by the third pin.

[0011] Preferably, a first pin is provided between the central cylinder and the movable cylinder, and the central cylinder and the movable cylinder are connected and fixed by the first pin.

[0012] Preferably, a central groove is provided at the top center of the central cylinder, and a connecting cylinder is provided inside the central cylinder. The connecting cylinder is connected to the sealing tool, and a fifth pin is provided between the connecting cylinder and the central cylinder. The connecting cylinder is connected and fixed to the central groove on the central cylinder by the fifth pin.

[0013] Compared with the prior art, the beneficial effects of the present invention are: This invention, by incorporating an anchoring component, allows for the anchoring of the bridge plug body at a predetermined depth during fracturing operations. It is also applicable to anchoring at large diameter changes within the casing, improving the anchoring effect and ensuring fracturing efficiency. As the tool string advances within the casing, the protective component effectively protects the bridge plug body, preventing damage from burrs protruding from the casing wall and changes in casing diameter that could lead to plugging failure. Furthermore, during plugging, a cover plate provides support against the casing wall, ensuring operational stability and plugging effectiveness, thus improving overall fracturing efficiency.

[0014] This invention incorporates an anchoring component. During fracturing operations, the cylinder is propelled towards a predetermined depth under external hydraulic pressure, exerting force on the clamping plate. The clamping plate moves towards the casing wall until the anchoring block on the clamping plate engages with the casing, completing the anchoring. For some locations with large diameter changes inside the casing, the clamping plate can achieve anchoring at these points, improving applicability. During fracturing operations, rapid anchoring can be achieved, improving the overall efficiency of fracturing operations.

[0015] This invention incorporates a protective component. During fracturing operations, the tool string is pumped to a predetermined depth. As the tool string is pushed inside the casing, a breakable cover plate located outside the first rubber cylinder protects it, preventing burrs or other debris from the casing's inner wall from scratching or damaging the first rubber cylinder and affecting subsequent sealing. Simultaneously, during plugging, the cover plate provides support against the casing's inner wall, ensuring operational stability. Furthermore, the first and second rubber cylinders compress the cover plate, causing it to break, ensuring smooth plugging and maximizing fracturing efficiency. Attached Figure Description

[0016] Figure 1 This is a plan view of a downhole bridge plug proposed in this invention; Figure 2 for Figure 1 Enlarged view of point A in the middle; Figure 3 This is a schematic diagram of the structure of a downhole bridge plug proposed in this invention; Figure 4 This is a schematic diagram of the internal structure of a downhole bridge plug proposed in this invention; Figure 5 This is a schematic diagram of the first stage of a downhole bridge plug proposed in this invention. Figure 6 This is a schematic diagram of the second stage of a downhole bridge plug proposed in this invention; Figure 7 This is a schematic diagram of the third stage of a downhole bridge plug proposed in this invention; Figure 8This is a schematic diagram of the fourth stage of a downhole bridge plug proposed in this invention; Figure 9 This is a schematic diagram of the fifth stage of a downhole bridge plug proposed in this invention.

[0017] In the diagram: 1. Center cylinder; 2. Movable cylinder; 3. First pin; 4. First anti-protrusion ring; 5. First rubber sleeve; 6. Second rubber sleeve; 7. Second anti-protrusion ring; 8. Pressure cylinder; 9. Mounting plate; 10. Cover plate; 100. Reinforcing rib; 101. Connecting plate; 102. Crackable plate; 103. Movable plate; 104. Second pin; 105. Third pin; 11. Fourth pin; 12. Bottom cylinder; 13. Fifth pin; 14. Clamping plate; 15. Support rod; 16. Connecting cylinder; 17. Sealing tool; 18. Perforating gun. Detailed Implementation

[0018] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0019] Reference Figure 1-9A downhole bridge plug includes a central cylinder 1 with a central groove at the top center. A connecting cylinder 16 is disposed inside the central cylinder 1, and a fifth pin 13 is disposed between the connecting cylinder 16 and the central cylinder 1. The connecting cylinder 16 is connected and fixed to the central groove on the central cylinder 1 via the fifth pin 13. A setting tool 17 is disposed on one side of the central cylinder 1 and is mounted on the outer wall of the tubing string. The connecting cylinder 16 and the setting tool 17 are interconnected. A perforating gun 18 is disposed on one side of the setting tool 17 and is mounted on the outer wall of the tubing string. During downhole operations, after setting at a predetermined depth, the fractured section is isolated. The perforating gun 18 is raised to the target formation, and the perforation is detonated to complete the fracturing operation of that section. The outer wall of the core cylinder 1 is provided with a movable cylinder 2, which is a cylindrical structure. The movable cylinder 2 is slidably mounted on the core cylinder 1. A first pin 3 is provided between the core cylinder 1 and the movable cylinder 2, and the core cylinder 1 and the movable cylinder 2 are connected and fixed by the first pin 3. The piston in the setting tool 17 moves towards the movable cylinder 2 after being hydraulically pressurized and applies a force to the movable cylinder 2. When the force applied to the movable cylinder 2 exceeds the bearing limit of the first pin 3, the first pin 3 is sheared, and the movable cylinder 2 moves. The outer wall of the core cylinder 1 is provided with a first anti-protrusion ring 4, which is located on the lower side of the movable cylinder 2. The top of the first anti-protrusion ring 4 is in contact with the bottom of the movable cylinder 2. The contact surfaces of the movable cylinder 2 and the first anti-protrusion ring 4 are both wedge-shaped surfaces. A first rubber sleeve 5 is fixedly installed at the bottom of ring 4. The first rubber sleeve 5 is made of elastic material (usually high-performance rubber, such as hydrogenated nitrile rubber). The first rubber sleeve 5 is compressed and deformed by the axial force of the first anti-protrusion ring 4. When the axial force exceeds the elastic limit of the first rubber sleeve 5, the first rubber sleeve 5 undergoes plastic deformation. After the setting seal is released, the first rubber sleeve 5 still cannot return to its original shape. A first anti-protrusion ring 4 is also provided at the bottom of the first rubber sleeve 5. The first anti-protrusion rings 4 on both the top and bottom sides of the first rubber sleeve 5 are movably installed on the outer wall of the central cylinder 1. A second rubber sleeve 6 is provided on the outer wall of the central cylinder 1. The second rubber sleeve 6 is located below the first rubber sleeve 5. A second anti-protrusion ring 7 is fixedly installed at the top and bottom of the second rubber sleeve 6. The second rubber sleeve 6 and the second anti-protrusion ring 7 are... All 7 are movably installed on the outer wall of the central cylinder 1. The contact surface between the second anti-protrusion ring 7 and the first anti-protrusion ring 4 is a wedge-shaped surface. The outer wall of the central cylinder 1 is provided with a pressure cylinder 8, which is movably installed on the central cylinder 1. The top and bottom of the pressure cylinder 8 are both wedge-shaped surfaces. A fourth pin 11 is provided between the pressure cylinder 8 and the central cylinder 1. The pressure cylinder 8 is connected and fixed to the central cylinder 1 through the fourth pin 11. The outer wall of the central cylinder 1 is provided with a bottom cylinder 12, which is fixedly installed on the outer wall of the central cylinder 1. An anchoring component is provided between the bottom cylinder 12 and the pressure cylinder 8. The anchoring component can assist the first rubber sleeve 5 in fixing and sealing at a predetermined depth. Eight sets of protective components are provided on the side of the pressure cylinder 8 away from the central cylinder 1 to ensure the setting and sealing effect during fracturing operations and improve the overall fracturing efficiency.By incorporating an anchoring assembly, the bridge plug body can be anchored at a predetermined depth during fracturing operations. This assembly is also applicable to anchoring at large diameter changes within the casing, improving anchoring effectiveness and ensuring fracturing efficiency. As the tool string advances within the casing, the protective assembly effectively protects the bridge plug body, preventing damage from burrs or changes in casing diameter that could lead to plug failure. Furthermore, during plugging, the cover plate 10 provides support against the casing wall, ensuring operational stability and plugging effectiveness, thus improving overall fracturing efficiency.

[0020] As an optimized solution for downhole bridge plug technology according to the present invention, the anchoring assembly includes clamping plates 14. Eight sets of clamping plates 14 are slidably installed on the top of the bottom cylinder 12. The side of the clamping plate 14 near the pressure cylinder 8 is a wedge-shaped surface. After the pressure cylinder 8 moves downward into place, it can press against the clamping plate 14 to assist in its positioning and fixation. An anchoring blocks are fixedly installed on the side of the clamping plate 14 away from the central cylinder 1. The number of anchoring blocks is set according to the area of ​​the side of the clamping plate 14 away from the central cylinder 1. A support rod 15 is provided between the clamping plate 14 and the pressure cylinder 8. Both ends are rotatably connected to the clamping plate 14 and the pressure cylinder 8, respectively. With the anchoring component, during fracturing operations, the pressure cylinder 8 is pushed towards the predetermined depth under the action of external hydraulic pressure and applies force to the clamping plate 14. The clamping plate 14 moves towards the casing wall until the anchoring block on the clamping plate 14 is inserted into the casing, completing the anchoring. For some large diameter change positions inside the casing, the clamping plate 14 can achieve anchoring at the large diameter change points, improving applicability. During fracturing operations, rapid anchoring can be achieved, improving the overall fracturing operation efficiency.

[0021] As an optimized solution for downhole bridge plug technology according to the present invention, the protective component includes a mounting plate 9, which is fixedly installed on the side wall of the pressure cylinder 8 away from the central cylinder 1. A movable plate 103 is slidably mounted on the mounting plate 9, and a second pin 104 is provided between the movable plate 103 and the mounting plate 9. The movable plate 103 is connected and fixed to the mounting plate 9 through the second pin 104. A connecting plate 101 is rotatably mounted on the movable plate 103, and a crackable plate 102 is fixedly mounted on the side of the connecting plate 101 near the movable plate 103. The crackable plate 102 is rotatably connected to the movable plate 103 via a rotating shaft. A third pin 105 is provided between the movable plate 103 and the rotating shaft. The rotating shaft is connected and fixed to the movable plate 103 via the third pin 105. The crackable plate 102 has a bearing limit, and easy-breakable edges are evenly distributed on the crackable plate 102. When the crackable plate 102 is subjected to an external force that exceeds its bearing limit, the crackable plate 102 will break. A cover plate 10 is fixedly installed on the connecting plate 101. The cover plate 10 is located outside the first rubber cylinder 5. When the tool string is put in... The tool string is advanced to a predetermined depth. During the advancement of the tool string, the cover plate 10 can protect the first rubber cylinder 5 from the outside, preventing protrusions, burrs, and sleeve transition points inside the casing from scratching and damaging the first rubber cylinder 5, affecting the annular sealing and causing fracturing operation failure. The side wall of the cover plate 10 away from the central cylinder 1 is uniformly provided with reinforcing ribs 100, which can improve the overall strength of the cover plate 10 and ensure the protective effect. With the protective components, during fracturing operations, when the tool string is pumped to the predetermined depth and pushed inside the casing, the first rubber cylinder 5 is protected by the fractureable cover plate 10 outside the first rubber cylinder 5, preventing burrs on the inner wall of the casing from scratching and damaging the first rubber cylinder 5 during the pushing process, affecting the subsequent sealing performance. At the same time, during sealing, the cover plate 10 is pressed against the inner wall of the casing for support, ensuring the stability of the operation. Meanwhile, the first rubber cylinder 5 and the second rubber cylinder 6 squeeze the cover plate 10 to break it, ensuring smooth sealing and ensuring the efficiency of fracturing operations.

[0022] When using this invention, during fracturing operations, the tubing string and tool string are assembled. The tool string mainly includes a connecting cylinder 16, a central cylinder 1 and its upper components, a setting tool 17, and a perforating gun 18. After the tool string and tubing string are assembled, fracturing operations are prepared. After the tool string is pumped to the predetermined depth, pumping is stopped. At this time, pressure is applied to the inside of the tubing string, and the setting tool 17 generates a setting force that acts on the movable cylinder 2. When the setting force exceeds the bearing limit of the first pin 3, the first pin 3 is sheared. The movable cylinder 2 advances towards the predetermined depth and applies an axial force to the first anti-protrusion ring 4. After being compressed, the first anti-protrusion ring 4 advances towards the predetermined depth and compresses the first rubber sleeve 5. The first rubber sleeve 5 is compressed and deformed under the axial force. Simultaneously, the second rubber sleeve 6 is compressed and deformed. 6 deforms towards the side closer to the sleeve wall and squeezes the cover plate 10. The second pin 104 is sheared off. The cover plate 10 slides towards the side closer to the predetermined depth. After sliding to the lowest point, the second rubber cylinder 6 continues to expand towards the side closer to the sleeve and continues to squeeze the cover plate 10. The third pin 105 is sheared off. The cover plate 10 rotates. When the cover plate 10 rotates towards the sleeve side under the expansion and compression of the second rubber cylinder 6 until it comes into contact with it, the second rubber cylinder 6 continues to expand until it exceeds the bearing limit of the crackable plate 102. The crackable plate 102 breaks, the cover plate 10 falls off, and the first rubber cylinder 5 seals the annular space between the tool string and the sleeve. As the first rubber sleeve 5 and the second rubber sleeve 6 continue to compress and deform, the second anti-protrusion ring 7 advances towards the predetermined depth and squeezes the pressure cylinder 8. When the force exceeds the bearing limit of the fourth pin 11, the fourth pin 11 is sheared off, the pressure cylinder 8 advances towards the predetermined depth and squeezes the clamping plate 14. Simultaneously, the support rod 15 is pulled open, and the clamping plate 14 continues to advance towards the casing wall until the anchoring block on the clamping plate 14 is anchored on the casing wall. Once the anchoring is complete, the annular sealing of the first rubber sleeve 5 is finished. When the pulling force of the tubing string exceeds the bearing limit of the fifth pin 13, the fifth pin 13 is sheared and released. The tubing string is then pulled up to the predetermined section, and the perforation gun 18 detonates the perforation. After the perforation is completed, the tubing string is pulled up, and a sealing ball is pumped into the central groove of the central cylinder 1 to complete the sealing. The fractured section is then isolated. After perforation is completed, pre-fracturing fluid, sand-carrying fluid and displacement fluid are pumped into the casing to complete the fracturing operation; The main procedures for fracturing operations include the following steps: First stage: Assemble the tubing string and tool string. The tool string mainly includes the connecting cylinder 16, the central cylinder 1 and its upper parts, the setting tool 17 and the perforating gun 18. After the tool string is pumped to the predetermined depth, it pressurizes the inside of the tubing string. The setting tool 17 generates a setting force and acts on the movable cylinder 2. The first pin 3 is sheared, as shown in the figure. Second stage: The first rubber cylinder 5 is compressed and deformed after being subjected to axial force, the second rubber cylinder 6 is squeezed and compressed and deformed, the second pin 104 is sheared, the cover plate 10 slides towards the side closer to the predetermined depth, and after sliding to the lowest point, the second rubber cylinder 6 continues to expand towards the side closer to the sleeve and continues to squeeze the cover plate 10, as shown in the figure. Third stage: The crackable plate 102 breaks, the cover plate 10 falls off, and the first rubber sleeve 5 seals the annular space between the tool string and the sleeve, as shown in the figure; Fourth stage: The second anti-outburst ring 7 advances towards the predetermined depth and squeezes the pressure cylinder 8. When the force exceeds the bearing limit of the fourth pin 11, the fourth pin 11 is sheared off. The pressure cylinder 8 advances towards the predetermined depth and squeezes the clamping plate 14. Simultaneously, the support rod 15 is pulled open, and the clamping plate 14 continues to advance towards the casing wall until the anchoring block on the clamping plate 14 is anchored to the casing wall. Anchoring is completed, as shown in the figure. Fifth stage: Pull up the tubing string. When the pulling force exceeds the bearing limit of the fifth pin 13, the fifth pin 13 is sheared off, and the tubing string is released. Pull up the tubing string to the predetermined layer, and the perforating gun 18 detonates the perforation.

[0023] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

[0024] The above description is merely a preferred embodiment 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 downhole bridge plug, comprising a central cylinder (1), wherein a setting tool (17) is disposed on one side of the central cylinder (1), and a perforating gun (18) is disposed on one side of the setting tool (17), characterized in that: The outer wall of the central cylinder (1) is provided with a movable cylinder (2), the outer wall of the central cylinder (1) is provided with a first anti-protrusion ring (4), the bottom of the first anti-protrusion ring (4) is fixedly installed with a first rubber cylinder (5), the bottom of the first rubber cylinder (5) is also provided with a first anti-protrusion ring (4), the outer wall of the central cylinder (1) is provided with a second rubber cylinder (6), the top and bottom of the second rubber cylinder (6) are fixedly installed with a second anti-protrusion ring (7), the outer wall of the central cylinder (1) is provided with a pressure cylinder (8), the outer wall of the central cylinder (1) is provided with a bottom cylinder (12), the bottom cylinder (12) is fixedly installed on the outer wall of the central cylinder (1), the bottom cylinder (12) is provided with an anchoring assembly including a clamping plate (14) between the bottom cylinder (12) and the pressure cylinder (8), and the side of the pressure cylinder (8) away from the central cylinder (1) is provided with eight sets of protective assemblies including a cover plate (10); The eight sets of card plates (14) are slidably installed on the top of the bottom cylinder (12). An anchor block is fixedly installed on the side of the card plate (14) away from the center cylinder (1). A support rod (15) is provided between the card plate (14) and the pressure cylinder (8). The two ends of the support rod (15) are rotatably connected to the card plate (14) and the pressure cylinder (8) respectively. The cover plate (10) is located on the outside of the first rubber cylinder (5). The pressure cylinder (8) is fixedly installed on the side wall away from the central cylinder (1) with an installation plate (9). A movable plate (103) is slidably installed on the installation plate (9). A connecting plate (101) is rotatably installed on the movable plate (103). The cover plate (10) is fixedly installed on the connecting plate (101).

2. The downhole bridge plug according to claim 1, characterized in that: The movable cylinder (2) is slidably mounted on the central cylinder (1). The first anti-protrusion ring (4) is set on the lower side of the movable cylinder (2). The top of the first anti-protrusion ring (4) is in contact with the bottom of the movable cylinder (2). The surfaces of the movable cylinder (2) and the first anti-protrusion ring (4) in contact with each other are wedge-shaped surfaces. The first anti-protrusion rings (4) on the top and bottom sides of the first rubber cylinder (5) are movably mounted on the outer wall of the central cylinder (1).

3. A downhole bridge plug according to claim 2, characterized in that: The second rubber tube (6) is located on the lower side of the first rubber tube (5). The second rubber tube (6) and the second anti-protrusion ring (7) are both movably installed on the outer wall of the central tube (1). The contact surface between the second anti-protrusion ring (7) and the first anti-protrusion ring (4) is a wedge-shaped surface.

4. A downhole bridge plug according to claim 3, characterized in that: The pressure cylinder (8) is movably mounted on the central cylinder (1). The top and bottom of the pressure cylinder (8) are both wedge-shaped surfaces. The side of the clamping plate (14) near the pressure cylinder (8) is also a wedge-shaped surface. A fourth pin (11) is provided between the pressure cylinder (8) and the central cylinder (1). The pressure cylinder (8) is connected and fixed to the central cylinder (1) through the fourth pin (11).

5. A downhole bridge plug according to claim 4, characterized in that: A second pin (104) is provided between the movable plate (103) and the mounting plate (9), and the movable plate (103) is connected and fixed to the mounting plate (9) through the second pin (104).

6. A downhole bridge plug according to claim 5, characterized in that: The protective assembly also includes a crackable plate (102), which is fixedly installed on the side of the connecting plate (101) near the movable plate (103). The crackable plate (102) is rotatably connected to the movable plate (103) via a rotating shaft.

7. A downhole bridge plug according to claim 6, characterized in that: A third pin (105) is provided between the movable plate (103) and the rotating shaft, and the rotating shaft is connected and fixed to the movable plate (103) through the third pin (105).

8. A downhole bridge plug according to claim 7, characterized in that: A first pin (3) is provided between the central cylinder (1) and the movable cylinder (2), and the central cylinder (1) and the movable cylinder (2) are connected and fixed by the first pin (3).

9. A downhole bridge plug according to claim 8, characterized in that: A central groove is provided at the top center of the central cylinder (1). A connecting cylinder (16) is provided inside the central cylinder (1). The connecting cylinder (16) is connected to the sealing tool (17). A fifth pin (13) is provided between the connecting cylinder (16) and the central cylinder (1). The connecting cylinder (16) is connected and fixed to the central groove on the central cylinder (1) by the fifth pin (13).

Images