Bridge Plug

Abstract

The present invention relates to the technical field of oil and gas production, and in particular to a bridge plug. It comprises: a cylinder, a seat sleeve, a rubber cylinder, a cone cylinder, a slip, and a lower joint; the seat sleeve is sleeved on the outer wall of the first end of the cylinder, the first end of the cone cylinder is sleeved on the second end of the cylinder, the rubber cylinder is sleeved on the outer wall of the cylinder and the two ends are close to the seat sleeve and the cone cylinder respectively; the slip is a through-cylindrical integrated structure, the inner diameter gradually decreases from the first end to the second end of the slip, the outer wall is provided with a plurality of annular teeth, and a gap is provided from the first end to the second end of the slip, and the gaps are multiple and spaced around the inner wall of the slip; wherein the inner wall of the first end of the slip is sleeved on the outer wall of the second end of the cone cylinder; a channel connecting the two ends is provided in the middle of the lower joint, the first end of the lower joint cooperates with the second end of the slip, and a clamping groove is provided in the channel of the lower joint. The slip of the bridge plug is an integrated structure, which can avoid loosening and dislocation after the seat is hung, and can be made of soluble materials to realize the full dissolution of the bridge plug.

Description

Technical Field

[0001] The invention relates to the technical field of oil and gas production, in particular to a bridge plug. Background Art

[0002] In the process of oil and gas production, in order to increase oil and gas production, multi-layer staged fracturing technology is used in the mining process. Among them, bridge plug + perforation technology is the most widely used fracturing technology, and bridge plug is the staged fracturing technology and its important downhole layered plugging tool.

[0003] In order to ensure production after fracturing, the bridge plug can be designed as a soluble bridge plug, that is, the bridge plug will dissolve after a period of time after the fracturing is completed, thereby solving a series of problems in the existing bridge plug milling operation and affecting the subsequent transformation. However, in order to ensure the strength of the bridge plug, the existing technology will inlay ceramic inserts on the slips of the bridge plug. Such inserts will not dissolve over time, and the slips and casing will not be firmly sealed, resulting in looseness, dislocation and other problems.

[0004] Therefore, the above-mentioned technical problems need to be solved urgently. Summary of the invention

[0005] The main purpose of the present invention is to provide a bridge plug with a new structure, so as to solve the above technical problems.

[0006] The purpose of the present invention and the technical problem to be solved are achieved by adopting the following technical solutions. A bridge plug proposed in the present invention comprises:

[0007] A cylinder, a seat seal, a rubber cylinder, and a cone cylinder. The seat seal is sleeved on the outer wall of the first end of the cylinder. The inner diameter of the first end of the cone cylinder is greater than the inner diameter of the second end. The first end of the cone cylinder is sleeved on the second end of the cylinder. The rubber cylinder is sleeved on the outer wall of the cylinder and its two ends are close to the seat seal and the cone cylinder respectively.

[0008] The slip is a through-cylindrical integrated structure, the inner diameter of which gradually decreases from the first end to the second end of the slip, and the outer wall is provided with a plurality of annular teeth, and a gap is provided from the first end to the second end of the slip, and the gap extends to a preset distance from the outer wall of the slip, and the gaps are multiple and spaced around the inner wall of the slip;

[0009] Wherein, the inner wall of the first end of the slip is sleeved on the outer wall of the second end of the cone;

[0010] A lower joint, wherein a passage connecting the two ends is arranged in the middle of the lower joint, the first end of the lower joint cooperates with the second end of the slip, and a clamping groove is arranged in the passage of the lower joint.

[0011] The purpose of the present invention and the solution to its technical problems can be further achieved by adopting the following technical measures.

[0012] Preferably, in the aforementioned bridge plug, the annular teeth are arranged side by side from the first end to the second end of the slip;

[0013] The cross section of the annular tooth is an equilateral trapezoid, and the angle between two sides of the equilateral trapezoid is 90 degrees.

[0014] Preferably, in the aforementioned bridge plug, the tooth surface of the annular teeth is provided with a cemented carbide coating.

[0015] Preferably, in the aforementioned bridge plug, the width of the gap is 0.01 mm-0.02 mm;

[0016] The remaining wall thickness of the slip at the position where the slit is opened is equal to 15-25% of the wall thickness of the slip.

[0017] Preferably, in the aforementioned bridge plug, the inner wall of the seat seal is provided with a plurality of rows of inverted teeth, and the outer wall of the first end of the cylinder is provided with inverted teeth meshing with the inverted teeth of the seat seal.

[0018] Preferably, the bridge plug provided in the embodiment of the present invention further includes:

[0019] The first protective rings are two in number and are respectively clamped on the outer walls at both ends of the rubber sleeve and are flush with the outer walls of the rubber sleeve.

[0020] Preferably, the bridge plug provided in the embodiment of the present invention further includes:

[0021] A second guard ring, wherein the cross section of the second guard ring is triangular, and the number of the second guard rings is two;

[0022] The end of the seat seal close to the rubber tube is provided with an outer chamfer, the first end of the rubber tube and the first protective ring together form an outer chamfer structure, the second end of the rubber tube and the first protective ring together form an outer chamfer structure, and the first end of the cone tube is provided with an outer chamfer;

[0023] One of the second protective rings is sleeved on the outer wall of the cylinder and is located between the seat sleeve and the rubber cylinder, and the two side surfaces of the second protective ring are respectively fitted with the outer chamfer of the seat sleeve and the outer chamfer structure of the first end of the rubber cylinder; another of the second protective rings is sleeved on the outer wall of the cylinder and is located between the cone cylinder and the rubber cylinder, and the two side surfaces of the second protective ring are respectively fitted with the outer chamfer of the first end of the cone cylinder and the outer chamfer structure of the second end of the rubber cylinder.

[0024] Preferably, the aforementioned bridge plug, wherein the second protective ring comprises a first open ring and a second open ring, the cross-section of the first open ring is a right-angled triangle, the cross-section of the second open ring is a right-angled triangle, a side wall where a right-angled side of the cross-section of the first open ring is located is provided with a circle of protrusions, and a side wall where a right-angled side of the cross-section of the second open ring is located is provided with a circle of grooves, and the protrusions cooperate with the grooves.

[0025] Preferably, the bridge plug provided in the embodiment of the present invention further includes:

[0026] A support ring is sleeved on the outer wall of the cylinder, located between the rubber cylinder and the cylinder body, and the support ring is located in the middle of the rubber cylinder.

[0027] Preferably, in the aforementioned bridge plug, a plurality of first protrusions are provided at the end of the second end of the slip, and the plurality of first protrusions are distributed around the second end of the slip at intervals;

[0028] A plurality of second protrusions are disposed at the end of the first end of the lower joint, and the plurality of second protrusions are distributed around the first end of the lower joint at intervals;

[0029] The end of the second end of the slip cooperates with the end of the first end of the lower joint, and the plurality of the first protrusions and the plurality of the second protrusions are inserted into each other's gaps.

[0030] By means of the above technical solution, the bridge plug of the present invention has at least the following advantages:

[0031] The bridge plug provided by the embodiment of the present invention has a slip as an integral structure, and a plurality of slits are arranged at intervals on the inner wall of the slip, so that when the bridge plug needs to be hung on the casing wall, the slip can be pulled by an operating tool to move toward the first end of the cone, the slit of the slip is expanded by the cone, and the annular teeth of the slip are clamped on the inner wall of the casing to achieve the seat hanging. Among them, since the slip is an integral structure without inlay teeth, it can effectively prevent damage to the upper casing, and avoid loosening and dislocation; in addition, also because the slip provided by the embodiment of the present invention is an integral structure without inlay teeth, the slip and the remaining parts of the bridge plug can be made of soluble materials, such as Meiji alloy materials, thereby solving the problem that insoluble inlay teeth easily block the channel.

[0032] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 is a structural schematic diagram of a bridge plug proposed in an embodiment of the present invention;

[0034] Figure 2 It is a schematic diagram of a slip structure of a bridge plug provided by an embodiment of the present invention;

[0035] Figure 3 is a schematic structural diagram of a bridge plug slip provided by an embodiment of the present invention from another perspective;

[0036] Figure 4 yes Figure 3 The enlarged view of point B;

[0037] Figure 5 is a schematic diagram of a first protection ring structure of a bridge plug provided by an embodiment of the present invention;

[0038] Figure 6 is a schematic structural diagram of a first protection ring of a bridge plug provided by an embodiment of the present invention from another viewing angle;

[0039] Figure 7 is a schematic diagram of the structure of a second protection ring of a bridge plug provided by an embodiment of the present invention;

[0040] Figure 8 is a schematic structural diagram of a second protection ring of a bridge plug provided by an embodiment of the present invention from another viewing angle;

[0041] Fig. 9 It is a schematic diagram of a lower joint structure of a bridge plug provided by an embodiment of the present invention;

[0042] Fig.10 It is a schematic structural diagram of a lower joint of a bridge plug provided by an embodiment of the present invention from another perspective.

[0043] Figure 1-Figure 10 The corresponding numbers in the bid are:

[0044] 1- cylinder, 2- seat sleeve, 3- rubber cylinder, 4- cone cylinder, 5- slip, 51- annular teeth, 52- gap, 53- first protrusion, 6- lower joint, 61- clamping groove, 62- second protrusion, 63- sawtooth structure, 7- inverted teeth, 8- first protective ring, 9- second protective ring, 91- first opening ring, 911- protrusion, 92- second opening ring, 921- groove, 10- support ring DETAILED DESCRIPTION

[0045] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation, structure, features and effects of the bridge plug proposed according to the present invention are described in detail below in combination with the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "embodiment" does not necessarily refer to the same embodiment. In addition, specific features, structures, or characteristics in one or more embodiments may be combined in any suitable form.

[0046] like Figure 1 As shown, a bridge plug proposed in one embodiment of the present invention comprises: a cylinder 1, a seat seal 2, a rubber cylinder 3, a cone cylinder 4, a slip 5, and a lower joint 6; the seat seal 2 is sleeved on the outer wall of the first end of the cylinder 1, the inner diameter of the first end of the cone cylinder 4 is larger than the inner diameter of the second end, the first end of the cone cylinder 4 is sleeved on the second end of the cylinder 1, the rubber cylinder 3 is sleeved on the outer wall of the cylinder 1, and the two ends are close to the seat seal 2 and the cone cylinder 4 respectively; the slip 5 is a through-cylindrical integrated structure, and the inner diameter gradually increases from the first end to the second end of the slip 5. It gradually decreases, and the outer wall is provided with multiple annular teeth 51. A gap 52 is opened from the first end to the second end of the slip 5, and the gap 52 extends to a preset distance from the outer wall of the slip 5. The gaps 52 are multiple and spaced around the inner wall of the slip 5; wherein the inner wall of the first end of the slip 5 is sleeved on the outer wall of the second end of the cone 4; a channel connecting the two ends is provided in the middle of the lower joint 6, the first end of the lower joint 6 cooperates with the second end of the slip 5, and a clamping groove 61 is provided in the channel of the lower joint 6.

[0047] Specifically, the cylinder body 1, the seat sleeve 2, the cone 4, the slip 5 and the lower joint 6 are all made of metal materials with a certain strength, and are preferably made of soluble metal materials, such as magnesium-based alloys, aluminum-based alloys, etc. The specific materials are not limited in the present invention as long as they can be guaranteed to be soluble in the well for a certain period of time.

[0048] The cylinder 1 is the main structure of the bridge plug, which is a tube with uniform outer and inner diameters. The seat sleeve 2 is a pipe sleeve that is sleeved on the first end of the cylinder 1 and connected to the first end of the cylinder 1. The connection between the seat sleeve 2 and the outer wall of the first end of the cylinder 1 is preferably a snap connection, and the two can move relative to each other under a certain pressure, that is, when there is pressure from the first end to the second end of the cylinder 1 acting on the seat sleeve 2, and when the pressure reaches a preset value, the seat sleeve 2 can be pushed, slide along the cylinder 1 and squeeze the rubber cylinder 3.

[0049] The connection between the cone 4 and the second end of the cylinder 1 can be a welding connection or a threaded connection, but it should be noted that after the two are connected, the outer diameter of the connection needs to be the same as the outer diameter of the cylinder 1, that is, the second end of the cylinder 1 needs to be stepped, so that after the cone 4 is sleeved on the second end of the cylinder 1, a smooth side wall is formed without protruding from the side wall surface of the cylinder 1.

[0050] The outer diameter of the slip 5 is less than or equal to the outer diameter of the cylinder 1. The slip 5 is a structure that can move and expand in the direction of the cone 4 under the action of external force when the bridge plug seat is hung on the casing, and after expansion, the copper drum annular teeth 51 need to be stuck on the inner wall of the casing. Therefore, the inner diameter of the cylindrical slip 5 gradually decreases from the first end to the second end, so that it just matches the shape of the cone 4. After moving in the direction of the first end of the cone 4, it can expand under the expansion pressure of the cone 4; in addition, although the slip 5 is set as an integrated structure, in order to ensure that the slip 5 can expand, a gap 52 is set on the inner wall of the slip 5, and the gap 52 is set from the first end to the second end of the slip 5. The setting of the gap 52 makes the side wall of the slip 5 only have a connection with local thickness at the position of the gap 52. Under the action of the expansion pressure, the gap 52 of the slip 5 can expand to a certain angle, that is, the slip 5 can expand. The number of the slits 52 may be multiple, for example, 6 or 8, and the multiple slits 52 are preferably evenly spaced and distributed on the inner wall of the slip 5 .

[0051] like Figure 1 , Fig. 9 and Fig.10 As shown, the lower joint 6 is a structure for lifting the cava 5 under the action of an auxiliary tool. In order to ensure the transparency of the entire bridge plug, the lower joint 6 also needs to be set as a transparent structure, and in order to prevent the pressure ball from acting in reverse on the lower joint 6 to block the channel, the second end of the lower joint 6 can be set to have a plurality of sawtooth structures 63 on the inner wall. Among them, the clamping groove 61 in the channel of the lower joint 6 can be an annular groove set in the channel.

[0052] The rubber sleeve 3 is a component that deforms and swells when the bridge plug is seated, that is, it can deform and swell under the pressure of the seat sleeve 2. The rubber sleeve 3 can also be made of a soluble material, so that all the components of the bridge plug can be made of soluble materials, and the bridge plug can be fully soluble, without the need for subsequent grinding and milling operations, reducing operating costs and operating time.

[0053] The method of using the bridge plug provided in the embodiment of the present invention is as follows: the bridge plug is lowered into a designated position of the casing in the oil well with the lower joint 6 as the head, and then, with the action of an auxiliary tool, the seat sleeve 2 is pressed down and the lower joint 6 is pulled up at the same time, so that the seat sleeve 2 deforms and swells the rubber sleeve 3 and squeezes it on the casing wall, and the lower joint 6 moves with the slip 5 toward the first end of the cone 4, so that the slip 5 expands and is squeezed on the casing wall, thereby realizing the seating of the bridge plug.

[0054] The bridge plug provided by the embodiment of the present invention has a slip 5 which is an integral structure, and a plurality of slits 52 are arranged at intervals on the inner wall of the slip 5. In this way, when the bridge plug needs to be hung on the casing wall, the slip 5 can be pulled toward the first end of the cone 4 by an operating tool, and the slit 52 of the slip 5 can be expanded by the cone 4, and the annular teeth 51 of the slip 5 can be stuck on the inner wall of the casing to achieve the seat hanging. Among them, since the slip 5 is an integral structure without insert teeth, it can effectively prevent damage to the upper casing, and avoid loosening and dislocation; in addition, since the slip 5 provided by the embodiment of the present invention is an integral structure without insert teeth, the slip 5 and the other parts of the bridge plug can be made of soluble materials, such as Meiji alloy materials, thereby solving the problem that insoluble insert teeth easily block the channel.

[0055] like Figure 1-Figure 4 As shown, in a specific implementation, the annular teeth 51 are arranged side by side from the first end to the second end of the slip 5; the cross-section of the annular teeth 51 is an equilateral trapezoid, and the angle between the two sides of the equilateral trapezoid is 90 degrees.

[0056] Specifically, the annular teeth 51 are arranged side by side on the side wall of the entire slip 5, which can effectively increase the number of annular teeth 51, that is, the number of annular teeth 51 can be effectively increased, and the contact area between the slip 5 and the casing wall can be increased when the slip 5 expands, and the friction force is increased, so that the bridge plug can be more firmly seated. In addition, the annular teeth 51 are arranged to have a trapezoidal cross section, and the tooth top of the annular teeth 51 is a circular surface, and the angles of the two sides of the equilateral trapezoidal cross section are set to 90 degrees, so that after the bridge plug is seated, the annular teeth 51 can be stably engaged with the inner wall of the casing, can withstand the upper and lower pulling forces, and will not move.

[0057] like Figure 1-Figure 4 As shown, in the specific implementation, in order to realize the full dissolution of the bridge plug, the slip 5 is set as an integrated structure. In this way, under the limitation of the material of the slip 5, the slip 5 is prone to low strength of the annular teeth 51, so a hard alloy coating is set on the tooth surface of the annular teeth 51. The hard alloy coating can be made of any material with high strength, such as manganese steel, tungsten steel and other coatings. The hard alloy coating can be formed on the tooth surface of the annular teeth 51 by welding, and the thickness can be selected according to actual needs. In this way, the strength and wear resistance of the annular teeth 51 of the slip 5 are effectively increased by setting the hard alloy coating.

[0058] like Figure 1-Figure 4As shown, in a specific implementation, the width of the slit 52 is 0.01mm-0.02mm, preferably 0.015mm, and the slit 52 can be processed by wire cutting. The remaining wall thickness of the position where the slit 52 is opened in the slip 5 is equal to 15-25% of the wall thickness of the slip 5. The remaining thickness can ensure that the slip 5 is an integrated structure, and the slit 52 of the slip 5 can also be expanded under the action of the expansion pressure, so that the slip 5 is expanded and pressed on the inner wall of the casing.

[0059] like Figure 1 As shown, in a specific implementation, the inner wall of the seat seal 2 is provided with multiple rows of inverted teeth 7, and the outer wall of the first end of the cylinder 1 is provided with inverted teeth meshing with the inverted teeth 7 of the seat seal 2.

[0060] Specifically, the inclination direction of the inverted teeth at the first end of the cylinder 1 is toward the first end of the cylinder 1, and the inclination direction of the inverted teeth 7 on the inner wall of the seat sleeve 2 is opposite to the inverted teeth on the cylinder 1. After the two are matched, the friction between the two can be increased, and the seat sleeve 2 can be avoided from being pushed toward the second end of the cylinder 1 when a smaller pressure acts on the seat sleeve 2.

[0061] like Figure 1 As shown, in a specific implementation, the bridge plug provided in an embodiment of the present invention further includes: a first protective ring 8, the number of which is two, which are respectively clamped on the outer walls of the two ends of the rubber cylinder 3 and are flush with the outer walls of the rubber cylinder 3.

[0062] Specifically, the first protection ring 8 is used to press the rubber sleeve 3 and prevent the rubber sleeve 3 from fully opening and fitting onto the inner diameter of the upper sleeve when the rubber sleeve 3 expands, thereby protecting the shoulders of both ends of the rubber sleeve 3 from being damaged when the rubber sleeve 3 is subjected to high pressure.

[0063] like Figure 1 and Figure 5-Figure 8 As shown, in a specific implementation, the bridge plug provided by an embodiment of the present invention further includes: a second protective ring 9, the cross-section of the second protective ring 9 is a triangle, and the number of the second protective rings 9 is two; wherein, an outer chamfer is provided at one end of the seat sleeve 2 close to the rubber cylinder 3, the first end of the rubber cylinder 3 forms an outer chamfer structure together with the first protective ring 8, the second end of the rubber cylinder 3 forms an outer chamfer structure together with the first protective ring 8, and the first end of the cone cylinder 4 is provided with an outer chamfer; one second protective ring 9 is sleeved on the outer wall of the cylinder body 1 and is located between the seat sleeve 2 and the rubber cylinder 3, and the two side surfaces of the second protective ring 9 are respectively fitted with the outer chamfer of the seat sleeve 2 and the outer chamfer structure of the first end of the rubber cylinder 3, and another second protective ring 9 is sleeved on the outer wall of the cylinder body 1 and is located between the cone cylinder 4 and the rubber cylinder 3, and the two side surfaces of the second protective ring 9 are respectively fitted with the outer chamfer of the first end of the cone cylinder 4 and the outer chamfer structure of the second end of the rubber cylinder 3.

[0064] Furthermore, the second protective ring 9 includes a first open ring 91 and a second open ring 92, the cross-section of the first open ring 91 is a right triangle, the cross-section of the second open ring 92 is a right triangle, a side wall of a right-angled side of the cross-section of the first open ring 91 is provided with a circle of protrusions 911, and a side wall of a right-angled side of the cross-section of the second open ring 92 is provided with a circle of grooves 921, and the protrusions 911 cooperate with the grooves 921.

[0065] Specifically, by setting the second protective ring 9 to have a triangular cross-section, the seat sleeve 2 moves toward the second end of the cylinder 1, and pressure is applied to the second protective ring 9. Since the contact surface is an inclined surface, the first open ring 91 of the second protective ring 9 can be expanded, and then the protrusion 911 with the groove 921 expands the second open ring 92 to a certain size. Finally, pressure is applied to the rubber cylinder 3. Since the inclined surface is in contact with the rubber cylinder 3, the contact surface with the end of the rubber cylinder 3 is increased, thereby avoiding direct pressure on the end of the rubber cylinder 3 to damage the rubber cylinder 3. At the same time, the action area is increased, which can also avoid pressure damage to the end of the rubber cylinder 3.

[0066] like Figure 1 As shown, in a specific implementation, the bridge plug provided by the embodiment of the present invention further includes: a support ring 10, which is sleeved on the outer wall of the cylinder 1, located between the rubber cylinder 3 and the cylinder 1, and the support ring 10 is located in the middle of the rubber cylinder 3.

[0067] Specifically, by providing the support ring 10, it is ensured that when the rubber sleeve 3 is sealed, the middle part bulges first and completely fits against the sleeve wall.

[0068] like Figure 1-Figure 3 and Figure 9-10 As shown, in a specific implementation, the end of the second end of the cava 5 is provided with a plurality of first protrusions 53, and the plurality of first protrusions 53 are distributed at intervals around the second end of the cava 5; the end of the first end of the lower joint 6 is provided with a plurality of second protrusions 62, and the plurality of second protrusions 62 are distributed at intervals around the first end of the lower joint 6; wherein, the end of the second end of the cava 5 cooperates with the end of the first end of the lower joint 6, and the plurality of first protrusions 53 and the plurality of second protrusions 62 are inserted into each other's gaps.

[0069] Specifically, by setting the first protrusion 53 and the second protrusion 62, the lower joint 6 can prevent the rotation of the slip 5. The first protrusion 53 and the second protrusion 62 can both be in the shape of a fan ring, so that when the two are inserted into each other's gap, the first protrusion 53 and the second protrusion 62 can form a complete fan ring.

[0070] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification, equivalent change and modification made to the above embodiment according to the technical essence of the present invention still falls within the scope of the technical solution of the present invention.

Claims

1. A bridge plug, characterized in that: include: A cylinder, a seat seal, a rubber cylinder, and a cone cylinder. The seat seal is sleeved on the outer wall of the first end of the cylinder. The inner diameter of the first end of the cone cylinder is greater than the inner diameter of the second end. The first end of the cone cylinder is sleeved on the second end of the cylinder. The rubber cylinder is sleeved on the outer wall of the cylinder and its two ends are close to the seat seal and the cone cylinder respectively. The slip is a through-cylindrical integrated structure, the inner diameter of which gradually decreases from the first end to the second end of the slip, and the outer wall is provided with a plurality of annular teeth, and a gap is provided from the first end to the second end of the slip, and the gap extends to a preset distance from the outer wall of the slip, and the gaps are multiple and spaced around the inner wall of the slip; Wherein, the inner wall of the first end of the slip is sleeved on the outer wall of the second end of the cone; A lower joint, wherein a passage connecting the two ends is provided in the middle of the lower joint, the first end of the lower joint cooperates with the second end of the slip, and a clamping groove is provided in the passage of the lower joint; Also includes: A first protective ring, wherein the number of the first protective rings is two, and the first protective rings are respectively clamped on the outer walls of the two ends of the rubber tube and are flush with the outer walls of the rubber tube; Also includes: A second guard ring, wherein the cross section of the second guard ring is triangular, and the number of the second guard rings is two; The end of the seat seal close to the rubber tube is provided with an outer chamfer, the first end of the rubber tube and the first protective ring together form an outer chamfer structure, the second end of the rubber tube and the first protective ring together form an outer chamfer structure, and the first end of the cone tube is provided with an outer chamfer; One of the second protective rings is sleeved on the outer wall of the cylinder and is located between the seat seal and the rubber cylinder, and two side surfaces of the second protective ring are respectively fitted with the outer chamfer of the seat seal and the outer chamfer structure of the first end of the rubber cylinder; another of the second protective rings is sleeved on the outer wall of the cylinder and is located between the cone cylinder and the rubber cylinder, and two side surfaces of the second protective ring are respectively fitted with the outer chamfer of the first end of the cone cylinder and the outer chamfer structure of the second end of the rubber cylinder; The annular teeth are arranged side by side from the first end to the second end of the slip; The cross section of the annular tooth is an equilateral trapezoid, and the angle between two sides of the equilateral trapezoid is 90 degrees.

2. The bridge plug according to claim 1, characterized in that: The tooth surface of the annular tooth is provided with a hard alloy coating.

3. The bridge plug according to claim 1, characterized in that: The width of the gap is 0.01mm-0.02mm; The remaining wall thickness at the position where the slip opens the slit is equal to 15-25% of the wall thickness of the slip.

4. The bridge plug according to claim 1, characterized in that: The inner wall of the seat seal is provided with a plurality of rows of inverted teeth, and the outer wall of the first end of the cylinder is provided with inverted teeth meshing with the inverted teeth of the seat seal.

5. The bridge plug according to claim 1, characterized in that: The second protective ring includes a first open ring and a second open ring, the cross-section of the first open ring is a right-angled triangle, the cross-section of the second open ring is a right-angled triangle, a side wall where a right-angled side of the cross-section of the first open ring is located is provided with a circle of protrusions, and a side wall where a right-angled side of the cross-section of the second open ring is located is provided with a circle of grooves, and the protrusions cooperate with the grooves.

6. The bridge plug according to claim 1, characterized in that: Also includes: A support ring is sleeved on the outer wall of the cylinder, located between the rubber cylinder and the cylinder body, and the support ring is located in the middle of the rubber cylinder.

7. The bridge plug according to claim 1, characterized in that: A plurality of first protrusions are disposed at the end of the second end of the slip, and the plurality of first protrusions are distributed around the second end of the slip at intervals; A plurality of second protrusions are disposed at the end of the first end of the lower joint, and the plurality of second protrusions are distributed around the first end of the lower joint at intervals; The end of the second end of the slip cooperates with the end of the first end of the lower joint, and the plurality of the first protrusions and the plurality of the second protrusions are inserted into each other's gaps.

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