Trigger type constant-speed dissolving bridge plug for slimming well

Abstract

The invention relates to a trigger type weight-reducing well constant-speed dissolving bridge plug which comprises a pull rod assembly, the upper portion of the pull rod assembly is sleeved with a ball seat body, the ball seat body is provided with a cosolvent cabin, the upper portion of the cosolvent cabin is provided with an upper opening device, and the lower portion of the cosolvent cabin is provided with a lower plug. An integrated metal push cylinder is arranged on the lower portion of the ball seat body, a center pipe is arranged on the lower portion of the integrated metal push cylinder, the center pipe is sleeved with an expansion rubber cylinder, protection bowls are arranged on the two sides of the expansion rubber cylinder, a movable slip is arranged on the lower portion of the expansion rubber cylinder, and a locking ring is arranged on the lower portion of the center pipe. A slip initial positioning ring is arranged at the bottom end of the movable slip, and a tooth block type slip assembly is arranged outside the slip initial positioning ring. According to the bridge plug, the degree of freedom of treatment means under complex working conditions is greatly improved, and the bridge plug is short in size, low in cost, controllable in dissolution starting time and controllable in dissolution process time.

Description

Technical Field

[0001] This invention relates to the field of fracturing operations in slimmed wells, and more specifically, to a trigger-type constant-speed dissolution bridge plug for slimmed wells. Background Technology

[0002] In the later stages of unconventional oil and gas resource development, economic benefits deteriorate. Speed-up and efficiency-enhancing measures, such as infill wells, repeated fracturing, and streamlined wellbore structures, are being implemented on a large scale. Drilling engineering, to achieve faster drilling, lock-in drilling cycles, and reduce cuttings handling, has begun to widely use streamlined wellbore structures (Slimmed Type I, bit: 346.1mm+250.8mm+171.5mm; Slimmed Type II, bit: 473.1mm+374.7mm+269.9mm+190.5mm). Reservoir stimulation tools, such as hydraulic fracturing, also need to be improved accordingly. Due to size limitations, conventional bridge plugs based on streamlined wellbore structures are no longer sufficient for reservoir stimulation under high-pressure and complex well conditions. Simultaneously, the increasing occurrence of casing deformation and leakage events due to infill wells directly leads to a higher probability of bridge plug pumping obstruction or other dangerous situations. Summary of the Invention

[0003] The technical problem to be solved by this invention is to provide a trigger-type slimming well constant-speed dissolution bridge plug, which greatly improves the freedom of processing methods under complex working conditions. It is a combination of multiple materials, short size, low cost, controllable dissolution start time, and controllable dissolution process time.

[0004] The technical solution adopted by this invention to solve its technical problem is as follows: A trigger-type slimming well constant-speed dissolution bridge plug is constructed, including a pull rod assembly. A ball seat body is sleeved on the upper part of the pull rod assembly. A solvent-coating chamber is provided on the ball seat body. An upper opening device is provided on the upper part of the solvent-coating chamber. A lower plug is provided on the lower part of the solvent-coating chamber. An integrated metal push cylinder is provided on the lower part of the integrated metal push cylinder. A central tube is provided on the lower part of the integrated metal push cylinder. An expansion sleeve is sleeved on the outside of the central tube. Protective cups are provided on both sides of the expansion sleeve. A movable slip is provided on the lower part of the expansion sleeve. A locking ring is provided on the lower part of the central tube. An initial positioning ring is provided at the bottom of the movable slip. A toothed slip assembly is provided on the outside of the initial positioning ring.

[0005] According to the above scheme, the solvent chambers are six evenly distributed on the ball seat body. According to the above scheme, the movable slip is fixed to the central tube by anti-rotation bolts. According to the above scheme, the movable slip has a guide groove.

[0006] According to the above scheme, the expansion tube is in the form of a hollow cylinder, the length of the expansion tube accounts for 2 / 3 of the total length of the central tube, and the length of the movable slip sleeve accounts for 1 / 3 of the total length of the central tube.

[0007] According to the above scheme, the tie rod assembly has a stepped shaft structure, and the tie rod assembly includes a first step, a second step, a third step, a fourth step, and a fifth step; the first step, the third step, the fourth step, and the fifth step are all hollow structures, the second step is a solid structure, the first step and the second step are threaded together, and the first step and the second step are connected by positioning bolts.

[0008] According to the above scheme, a locking bolt is provided on the outside of the second step, and a sealing ring is provided at the end of the locking bolt. According to the above scheme, the toothed jaw assembly is provided with jaw teeth on the outside, and the toothed jaw assembly is fixed on the fifth step by a seated pin. The toothed jaw assembly is provided with a hollow guide shoe and a 13Cr friction plate from top to bottom. According to the above scheme, the fifth step of the hollowed-out guide shoe and the pull rod assembly is fixed by heat-applied adhesive bonding.

[0009] According to the above scheme, the upper opening device is a combination of a zirconium dioxide clamp and a nickel alloy sandwich diaphragm, the lower plug is a graphite-coated nickel alloy pin, the protective bowl is made of high-molecular polytetrafluoroethylene material, the expansion sleeve is a modified fluororubber elastomer, the slip teeth are made of ZGMn13-4 manganese steel alloy, the setting pin is made of powder metal, and the hollow guide shoe is made of polyetheretherketone material.

[0010] The trigger-type slimming well constant-rate dissolution bridge plug of the present invention has the following beneficial effects: 1. The hollowed-out guide shoe made of polyetheretherketone material used in this invention can save on the cost of soluble metals while maximizing quality. At the same time, it can fully support the squeegee to complete the preset action. Due to the small amount of material used, the drilling time is negligible. The 1.3mm tetragonal zirconia polycrystalline ceramic particles spraying can make good cooperation with the ZGMn13-4 manganese steel alloy squeegee teeth to ensure the maximum friction of the squeegee seat. The 20-40μm oxide film formed on the surface of soluble metal can prevent wellbore fluid interference under the premise of limited cost and realize the bridge plug dissolution at a constant rate from the inside. 2. Compared with drillable bridge plugs, the soluble bridge plug of this invention has better timeliness and simpler processing method. By using upgraded materials and a timed opening method of the flux chamber, it can realize the delayed processing of complex faults and the constant-speed dissolution of the bridge plug, which greatly improves the freedom of processing methods under complex working conditions. It meets the construction needs of the later working conditions of unconventional oil and gas resource development. Moreover, it is a bridge plug with multiple materials, short size, low cost, controllable dissolution start time, and controllable dissolution process time. Attached Figure Description

[0011] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings: Figure 1 This is a schematic cross-sectional view of the trigger-type slimming well constant-rate dissolution bridge plug of the present invention; Figure 2 This is a cross-sectional view of the tie rod assembly of the present invention; Figure 3 This is a cross-sectional view of the lower plug of the present invention; Figure 4 This is a cross-sectional view of the opening device of the present invention; Figure 5 This is a top view of the ball seat of the present invention; In the diagram: 1. Upper opening device, 2. Ball seat body, 3. Solvent chamber, 4. Lower plug, 5. Integrated metal push cylinder, 6. Pull rod assembly, 7. Positioning bolt, 8. Locking bolt, 9. Sealing ring, 10. Protective bowl, 11. Expansion sleeve, 12. Central tube, 13. Movable slip, 14. Anti-rotation bolt, 15. Locking ring, 16. Slip initial positioning ring, 17. Tooth block slip assembly, 18. Slip teeth, 19. Sealing pin, 20. Hollowed-out guide shoe, 21. 13Cr friction plate, 601. First step, 602. Second step, 603. Third step, 604. Fourth step, 605. Fifth step. Detailed Implementation

[0012] To provide a clearer understanding of the technical features, objectives, and effects of the present invention, specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0013] like Figure 1-5 As shown, the trigger-type slimming well constant-speed dissolution bridge plug of the present invention includes a pull rod assembly 6, a ball seat body 2 is sleeved on the upper part of the pull rod assembly 6, a solvent chamber 3 is provided on the ball seat body 2, an upper opening device 1 is provided on the upper part of the solvent chamber 3, a lower plug 4 is provided on the lower part of the solvent chamber 3, an integrated metal push cylinder 5 is provided on the lower part of the ball seat body 2, a central tube 12 is provided on the lower part of the integrated metal push cylinder 5, an expansion rubber cylinder 11 is sleeved on the outside of the central tube 12, protective bowls 10 are provided on both sides of the expansion rubber cylinder 11, a movable slip 13 is provided on the lower part of the expansion rubber cylinder 11, a locking ring 15 is provided on the lower part of the central tube 12, an initial positioning ring 16 is provided at the bottom of the movable slip 13, and a toothed slip assembly 17 is provided on the outside of the initial positioning ring 16.

[0014] Six solvent chambers 3 are evenly distributed on the ball seat body 2. Movable slips 13 are fixed to the central tube 12 by anti-rotation bolts 14. Movable slips 13 have guide grooves. The expansion sleeve 11 is a hollow cylinder, with its length accounting for 2 / 3 of the total length of the central tube 12, and the length of the movable slips 13 accounting for 1 / 3 of the total length of the central tube 12.

[0015] The tie rod assembly 6 has a stepped shaft structure, comprising a first step 601, a second step 602, a third step 603, a fourth step 604, and a fifth step 605. The first step 601, third step 603, fourth step 604, and fifth step 605 are hollow, while the second step 602 is solid. The first step 601 and the second step 602 are threaded together and connected by a positioning bolt 7. A locking bolt 8 is externally mounted on the second step 602, and a sealing ring 9 is provided at the end of the locking bolt 8. A toothed slip assembly 17 has slip teeth 18 externally mounted and is fixed to the fifth step 605 by a setting pin 19. The toothed slip assembly 17 has a perforated guide shoe 20 and a 13Cr friction plate 21 arranged from top to bottom. The fifth step 605 of the hollowed-out guide shoe 20 and the pull rod assembly 6 is fixed by heat-applied adhesive bonding.

[0016] The opening device 1 is a combination of a zirconium dioxide clamp and a nickel alloy sandwich diaphragm; the lower plug 4 is a graphite-coated nickel alloy pin; the protective bowl 10 is made of high-molecular polytetrafluoroethylene; the expansion sleeve 11 is made of modified fluororubber elastomer; the locking tooth 18 is made of ZGMn13-4 manganese steel alloy; the setting pin 19 is made of powder metal; and the hollowed-out guide shoe 20 is made of polyetheretherketone material.

[0017] In a preferred embodiment of the present invention, the bridge plug body is a hollow cylindrical structure, and the components are fitted together, including an upper opening device 1 consisting of a zirconium dioxide holder and a nickel alloy sandwich diaphragm, a ball seat body 2, a flux chamber 3, a lower plug 4 with a graphite-coated nickel alloy pin, an integrated metal push cylinder 5, a pull rod assembly 6, a positioning bolt 7, a locking bolt 8, a sealing ring 9, a protective cup made of high-molecular-weight polytetrafluoroethylene material 10, an expansion sleeve made of modified fluororubber elastomer 11, and a central tube 12. The system comprises six evenly distributed, solvent-filled capsules: a movable slipper 13 with guide grooves, an anti-rotation bolt 14, a locking ring 15, a slipper initial positioning ring 16, a toothed slipper assembly 17, slipper teeth made of ZGMn13-4 manganese steel alloy 18, powder metal setting pins 19, a hollow guide shoe made of polyetheretherketone material 20, and a 13Cr friction plate 21. These capsules are mounted on the upper part of an integrated metal pusher cylinder 5, which is tightly connected to the central tube 12 at its lower part. The movable slipper 13, toothed slipper assembly 17, hollow guide shoe 20, and 13Cr friction plate 21 are suspended from top to bottom by a tie rod assembly 6. The toothed slipper assembly 17 is divided into six segments, and there are eight positioning bolts 7, anti-rotation screws, and setting pins 19.

[0018] In a preferred embodiment of the present invention, the movable slip 13 is suspended and pulled to the pull rod assembly 6 according to the guide groove sequence. The toothed slip assembly 17 is fixed in sequence with a certain prestress, and finally fixed by heat assembly and gluing by the hollow guide shoe 20. Protective bowls 10 made of high-molecular-weight polytetrafluoroethylene are installed on both sides of the expansion cylinder 11. These bowls are hollow cylinders and tightly assembled on the upper part of the central tube 12, with the length of the protective bowls 10 occupying 2 / 3 of the length of the central tube 12. The movable slip 13 assembled at the bottom occupies 1 / 3 of the total length of the central tube 12, and the slip guide groove must be smooth and orderly. The movable slip 13 equipped with anti-rotation screws serves as a prestress and positioning element. The toothed slip assembly 17 is naturally suspended between the bottom hollow guide shoe 20 and the upper movable slip 13. When correctly assembled, the joint of the assembly and the guide groove can slide freely. A certain thickness of 13Cr friction plate 21 is evenly wrapped and covered on the outside of the hollow guide shoe 20. The hollow guide shoe 20 and the pull rod assembly 6 are fixed by heat bonding. After all parts are assembled, the seat seal pin 19 is finally placed to connect and fix them, and then sealed in a vacuum bag for preservation.

[0019] In a preferred embodiment of the present invention, when setting begins, the upper integrated metal pusher 5 achieves a downward thrust of ≥20t through gunpowder power or hydraulic power. The tie rod assembly 6 drives the integrated metal pusher 5 body to interact, instantly cutting off the eight setting pins 19 on the cylindrical cross-section. The toothed slip assembly 17 moves upward along the pre-assembled guide groove, pushing out the slip teeth 18 to complete the setting. Subsequently, the pump is started to pressurize to a preset value of 90MPa, instantly destroying the zirconium dioxide holder. The nickel alloy sandwich diaphragm descends, the lower plug 4 falls off, and after fully releasing the gelling acid (HCl) in the flux chamber 3, the nickel alloy sandwich diaphragm compresses and blocks the lower plug 4 at its original position. This achieves a constant-rate dissolution of the bridge plug from the inside out while the fracturing operation proceeds normally.

[0020] In a preferred embodiment of the present invention, the front end face of the hollow guide shoe 20 is milled flat and then hot-fitted with a 13Cr friction plate 21 with rounded corners, ensuring that the guide shoe body has a smooth cylindrical appearance. This significantly reduces the lowering friction under the premise of thin-well construction. The upper end of the hollow guide shoe 20 is threadedly connected to the toothed slip assembly 17, and the outer cylinder of the bridge plug body has two connecting holes for assembling the anti-rotation bolt 14 and the setting pin hole.

[0021] In a preferred embodiment of the present invention, the tie rod assembly 6 has a stepped shaft structure, consisting of five parts: a first step 601, a second step 602, a third step 603, a fourth step 604, and a fifth step 605. The first step 601, third step 603, fourth step 604, and fifth step 605 are hollow, while the first step 601 is solid. The first step 601 and the second step 602 are threaded together and fitted with positioning bolts 7. After setting, the wellhead is retrieved. The first step 601 has internal threads, and holes are formed on the outer circumferences of both the first step 601 and the second step 602. The hole in the second step 602 is threaded. The length order is: fifth step 605 > fourth step 604 > first step 601 > second step 602.

[0022] In a preferred embodiment of the present invention, the movable slip 13 is designed with an irregular outer conical surface, while the inner surface of the auxiliary guide groove is smooth and has a changing orientation, so that the slip can achieve uniform force after it opens. The movable slip 13 is suspended and pulled to the tie rod assembly 6 according to the guide groove sequence. The toothed slip assembly 17 is fixed in sequence with a certain prestress, and finally fixed by heat assembly and gluing by the hollow guide shoe 20. The upper part of the movable slip 13 is designed with internal threads, and the anti-rotation screw hole is assembled and connected to the thread. A locking ring 15 is provided at the anti-rotation screw hole and the corresponding thread connection to strengthen the overall structure of the fastening component. The uppermost ball seat is equipped with a flux chamber 3. The interior of the flux chamber 3 is coated to effectively prevent acid corrosion. The upper opening device 1 is composed of a zirconium dioxide holder and a nickel alloy sandwich diaphragm. The material and design size can withstand the impact during the well entry process. At the same time, the experiment shows that the zirconium dioxide holder and nickel alloy sandwich diaphragm involved in the opening device have moderate strength and can complete the descent and sealing. The lower part of the toothed slip assembly 17 is connected to the hollow guide shoe 20 by a fine thread hook, providing moderate sealing and strength. Due to the properties of the polyetheretherketone material of the hollow guide shoe 20, heat-fitting adhesive is used to reinforce the threaded connection. The toothed slip assembly 17 is divided into six segments, with the end faces engaging with the oblique conical surface of the guide groove of the movable slip 13, resulting in a smooth and flexible fit. The initial positioning ring is tightly fitted to the outside of the toothed slip assembly 17 to ensure the overall structural stability. Each segment of the toothed slip assembly 17 has four sets of slip teeth 18 (ZGMn13-4 manganese steel alloy) evenly arranged axially, installed at an angle of 15°-29° to the horizontal direction.

[0023] In a preferred embodiment of the present invention, the upper opening device 1 and the lower plug 4 are used together. To adapt to the high temperature and high pressure environment, the upper opening device 1 is composed of a high-strength zirconium dioxide clamp and a nickel alloy sandwich diaphragm. The ball seat body 2 is made of ordinary steel. The inner wall of the flux chamber 3 is pretreated with a cold-sprayed viscous amorphous glass glaze coating, which can effectively prevent corrosion by 30% gelling acid (HCl) flux. The lower plug 4 is made of high-strength graphite-plated nickel alloy pin. The integrated metal push cylinder 5 and the pull rod assembly 6 are made of alloy steel. The positioning bolt 7, locking bolt 8, anti-rotation bolt 14, and setting pin 19 are all made of alloy powder metal material, which can quickly shear and break under a certain prestress, with less debris, and does not affect the movement of moving parts. The sealing ring 9, locking ring 15, and initial positioning ring of the slips are made of vulcanized nitrile rubber. The toothed slip assembly 17 and slip teeth 18 are made of ZGMn13-4 manganese steel coated with 1.3mm tetragonal zirconia polycrystalline ceramic particles. The hollow guide shoe 20 is made of polyetheretherketone material, which provides weight while ensuring strength. The friction plate is made of 13Cr alloy material. The expansion sleeve 11 is made of modified fluororubber elastomer, which has moderate strength and corrosion resistance. The protective cup 10 is made of high-molecular polytetrafluoroethylene material, which is softer than the expansion sleeve 11 and can effectively resist shock. The central tube 12 and movable slips 13 are made of soluble metal material. The soluble material is at least one of magnesium-aluminum alloy, magnesium-copper alloy, aluminum-copper alloy, etc., and the inner and outer surfaces of the soluble metal parts are pre-treated with oxidation to form an oxide film of 30-50μm, which can effectively prevent the corrosion of fracturing fluid and wellbore solution.

[0024] Example A ball seat for a trigger-type rapid dissolution bridge plug includes an upper opening device 1 composed of a zirconium dioxide holder and a nickel alloy sandwich diaphragm, a ball seat body 2, a flux chamber 3, a lower plug with a graphite-coated nickel alloy pin 4, an integrated metal push cylinder 5, a pull rod assembly 6, a positioning bolt 7, a locking bolt 8, a sealing ring 9, a protective cup made of high-molecular-weight polytetrafluoroethylene material 10, an expansion sleeve made of modified fluororubber elastomer 11, a central tube 12, a movable slip with a guide groove 13, an anti-rotation bolt 14, a locking ring 15, a slip initial positioning ring 16, a toothed slip assembly 17, slip teeth made of ZGMn13-4 manganese steel alloy 18, a powder metal setting pin 19, a hollowed-out guide shoe made of polyetheretherketone material 20, and a 13Cr friction plate 21. The metal body of the trigger-type slimming well constant-speed dissolution bridge plug is made of at least one of the following materials: magnesium-aluminum alloy, magnesium-copper alloy, and aluminum-copper alloy, with a material strength of 250 MPa. The soluble metal material surface undergoes an oxidation pretreatment to form a 30-50μm oxide film, and a thick, high-temperature molybdenum disulfide grease is applied before insertion into the well to prevent damage to the oxide film caused by impacts. The toothed slip assembly 17 and slip teeth 18 (ZGMn13-4 manganese steel alloy) are made of high-manganese steel. Specifically, ZGMn13-4 material is supplemented with varying amounts of alloying elements such as Cr, Mo, B, and Re. Its Brinell hardness value is ≥220HB; impact toughness value is ≥140J / cm. The surface is coated with 1.3mm tetragonal zirconia polycrystalline ceramic particles, the main components of which are t-ZrO2+Y2O3+CeO2, with a Mohs hardness of up to 7. The component hardness is greater than that of conventional casing materials such as J55, H40, K55, N80, L80, P110, and Q125. The positioning locking bolt 8, anti-rotation bolt 14, and setting pin 19 are made of powder metal, specifically aluminum bronze / steel bimetallic material, which has high strength and high density. After setting, it fractures brittlely and forms fine particles.

[0025] This invention also provides a method for trigger-type well slimming constant-rate dissolution of bridge plugs, comprising the following steps: S1. Connect the first step 601, second step 602, third step 603, fourth step 604, and fifth step 605 of the tie rod assembly 6, and install eight positioning bolts 7 in sequence. The bridge plug body, tie rod assembly 6, and other accessories are assembled by fitting together. Then, install the locking bolts 8, the movable anti-rotation bolts 14, the initial positioning ring of the slip 16, and the setting pin 19 of the through-hole guide shoe 20. Finally, after tightening and checking the opening device 1 and the lower plug 4 of the integrated flux chamber 3, assemble them to the top of the bridge plug and proceed with well drilling.

[0026] S2. Assemble the pusher and bridge plug on the surface, and install the isolation gun and perforation gun in sequence. Then, set the prestress of the steel cable head, lower the tool string down into the well to target point A, and then use the fracturing truck in the process, at a speed of 1m. 3A small-displacement pump draws in clean water, propelling the tool string to target point B. An electrical signal transmitted via a steel cable drives the pressure / propellant, triggering the firing port projectile and the integrated metal pusher 5, releasing a downward force of ≥20t. This opens the toothed slips, with the manganese steel alloy slip teeth 18 engaging the inner wall of the sleeve, causing the rubber sleeve to compress and expand, completing the setting action.

[0027] S3. After setting, the soluble ball is pumped to the predetermined position to compress and expand the rubber sleeve, completing the sealing. At the same time, when the pressure rises to the limit, the 30% gelling acid (HCl) co-solvent is released, which mixes and dilutes with the wellbore fluid, rapidly dissolving the powdered metal setting pin 19, which is brittlely sheared, and begins to dissolve the bridge plug at a constant rate.

[0028] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.

Claims

1. A trigger-type slimming well constant-rate dissolution bridge plug, characterized in that, The device includes a pull rod assembly, with a ball seat body fitted on the upper part of the pull rod assembly. A solvent chamber is provided on the ball seat body, with an upper opening device on the upper part of the solvent chamber and a lower plug at the lower part of the solvent chamber. An integrated metal push cylinder is provided at the lower part of the ball seat body, with a central tube at the lower part of the integrated metal push cylinder. An expansion sleeve is fitted outside the central tube, with protective cups on both sides of the expansion sleeve. A movable slip is provided at the lower part of the expansion sleeve, and a locking ring is provided at the lower part of the central tube. An initial positioning ring is provided at the bottom of the movable slip, and a toothed slip assembly is provided outside the initial positioning ring.

2. The trigger-type slimming well constant-speed dissolution bridge plug according to claim 1, characterized in that, The flux chambers are six in number and are evenly distributed on the ball seat body.

3. The trigger-type slimming well constant-rate dissolution bridge plug according to claim 1, characterized in that, The movable slip is fixed to the central tube by anti-rotation bolts.

4. The trigger-type slimming well constant-rate dissolution bridge plug according to claim 1, characterized in that, The movable slip has a guide groove.

5. The trigger-type slimming well constant-rate dissolution bridge plug according to claim 1, characterized in that, The expansion tube is a hollow cylinder, and its length accounts for 2 / 3 of the total length of the central tube. The length of the movable slip sleeve accounts for 1 / 3 of the total length of the central tube.

6. The trigger-type slimming well constant-speed dissolution bridge plug according to claim 1, characterized in that, The tie rod assembly has a stepped shaft structure, comprising a first step, a second step, a third step, a fourth step, and a fifth step; the first step, the third step, the fourth step, and the fifth step are all hollow structures, while the second step is a solid structure. The first step and the second step are threaded together and connected by positioning bolts.

7. The trigger-type slimming well constant-rate dissolution bridge plug according to claim 6, characterized in that, A locking bolt is provided on the outside of the second step, and a sealing ring is provided at the end of the locking bolt.

8. The trigger-type slimming well constant-rate dissolution bridge plug according to claim 6, characterized in that, The toothed slip assembly is provided with slip teeth on the outside. The toothed slip assembly is fixed on the fifth step by a seated pin. The toothed slip assembly is provided with a hollow guide shoe and a friction plate from top to bottom.

9. The trigger-type slimming well constant-speed dissolution bridge plug according to claim 6, characterized in that, The fifth step of the hollowed-out guide shoe and the pull rod assembly is fixed by heat-applied adhesive bonding.

10. The trigger-type slimming well constant-rate dissolution bridge plug according to claim 1, characterized in that, The upper opening device is a combination of a zirconium dioxide clamp and a nickel alloy sandwich diaphragm; the lower plug is a graphite-coated nickel alloy pin; the protective bowl is made of high-molecular-weight polytetrafluoroethylene; the expansion sleeve is made of modified fluororubber elastomer; the locking teeth are made of manganese steel alloy; the setting pin is made of powder metal; and the hollowed-out guide shoe is made of polyetheretherketone material.

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