Semi-permanent mechanical throwing and fishing soluble shaft plugging bridge plug and method

Abstract

The invention discloses a semi-permanent mechanical throwing and fishing soluble shaft plugging bridge plug and method, and belongs to the technical field of bridge plugs, the bridge plug comprises a throwing joint, a central pipe, a fishing joint, a guide cone, a slip and a setting mechanism, the central pipe and the guide cone are provided with limiting pieces used for being matched with axial displacement of the central pipe, the limiting pieces are dissoluble, and the fishing joint is connected with the slip. Through limiting cooperation, setting and unsetting of the setting mechanism are achieved; during setting, the slip fixes the bridge plug on the inner wall of the casing pipe through inertia, the central pipe is lifted upwards to drive the piston to extrude hydraulic oil in the rubber sleeve lower connector into the sealing rubber sleeve, so that the sealing rubber sleeve is expanded, setting is completed, and at the moment, the central pipe is meshed and fixed with the limiting piece; during unsealing, the limiting piece is dissolved, the central pipe can axially move, the sealing rubber sleeve automatically shrinks, and the bridge plug is recycled by grabbing the fishing connector; the device is simple in structure and principle, convenient to recycle, capable of saving use cost, high in plugging pressure and capable of providing help for oil and gas development and construction of oil fields.

Description

Technical Field

[0001] This invention belongs to the field of bridge plug technology, specifically relating to a semi-permanent mechanically deployed soluble wellbore plugging bridge plug and its method. Background Technology

[0002] Unconventional oil and gas reservoirs are characterized by low porosity and low permeability, making extraction difficult and extremely inefficient using conventional methods. Horizontal drilling and staged fracturing techniques are generally employed to improve oil and gas recovery. The key to staged fracturing lies in the selection of the fracturing process and the performance of the downhole plugging tools. Different fracturing processes and plugging tools result in varying numbers of fracturing stages, leading to inconsistent improvements in the development efficiency of horizontal wells. Current trends in horizontal well staged fracturing aim to maximize the number of fracturing stages while ensuring effective fracturing operations, thereby maximizing the production potential of horizontal wells, improving single-well oil and gas recovery, and enhancing economic benefits. A crucial aspect of staged fracturing technology is the effectiveness of the plugging tools in isolating the wellbore. Therefore, bridge plugs, which act as wellbore sealers, play a vital role in the horizontal fracturing of unconventional oil and gas wells.

[0003] Existing fracturing bridge plugs can be categorized into permanent bridge plugs, mechanical bridge plugs, drop-and-retrieve bridge plugs, and soluble bridge plugs, each with its own advantages and disadvantages. Permanent bridge plugs, developed in the 1980s, have been widely used in oil and gas well sealing due to their fewer installation steps and accurate sealing location. However, their complex setting, retrieval, and unsealing operations make them unsuitable for unconventional shale gas fracturing operations. Drop-and-retrieve bridge plugs require unsealing and retrieval tools after each fracturing operation to retrieve the plug before reinstalling it for the next fracturing stage. This results in low fracturing efficiency, high costs, and long operation cycles. Mechanical bridge plugs have high pressure resistance and can provide high sealing of the fracturing section during staged fracturing. However, because these plugs cannot be retrieved and must be drilled away after fracturing, this also increases operating costs and time. After fracturing operations are completed, a dissolving solution is injected downhole to dissolve the soluble bridge plug. Once the bridge plug has dissolved, the wellhead is cleaned by circulation, and production can be started. However, the bridge plug has limited long-term sealing ability and is not suitable for long-cycle operations.

[0004] In oil and gas development, a removable, easily deployed, and easily retrieved device is needed to plug failed formations or temporarily seal wellbores, blocking the casing cross-section and isolating the upper and lower annulus. Because the casing is connected to the formation and experiences pressure, the plugging tool must have pressure-bearing capacity. Furthermore, the corrosiveness and sand content of the downhole medium significantly affect the setting and retrieval of the packer sleeve and slips. Summary of the Invention

[0005] To overcome the above-mentioned technical defects, the present invention provides a semi-permanent mechanically deployed soluble wellbore plug and method. Using this plug and method, the technical problem that existing plug structures are easily stuck in the casing after setting and are difficult to retrieve can be solved.

[0006] To achieve the above objectives, the present invention employs the following technical content:

[0007] A semi-permanent mechanically drop-and-retrieve soluble wellbore plugging bridge plug includes a drop-and-retrieve connector, a retrieval connector, a guide cone, a central tube, slips, and a setting mechanism;

[0008] The deployment connector is detachably connected to the central tube; the guide cone is sleeved on the outside of the central tube; the retrieval connector and the slip are both sleeved on the outside of the guide cone, and the bottom of the retrieval connector is connected to the top of the slip; a limiting component that cooperates with the central tube is provided between the guide cone and the central tube, and the limiting component is made of a soluble material; the bottom of the guide cone is connected to the setting mechanism, and the setting mechanism is sleeved on the outside of the central tube.

[0009] The setting mechanism includes an upper connector for the rubber tube, a sealing rubber tube, and a lower connector for the rubber tube connected in sequence. The upper connector for the rubber tube is connected to the bottom of the guide cone.

[0010] A piston is installed between the lower connector of the rubber sleeve and the central tube; the piston is connected to the central tube.

[0011] Furthermore, the guide cone has several guide holes evenly distributed around its conical surface; corresponding air guide holes are provided on the central tube; when the central tube is lifted, the guide holes and air guide holes connect to form an airflow channel.

[0012] Furthermore, a central plug is inserted inside the central tube; the central tube and the central plug are connected to the dispensing connector by a pin.

[0013] Furthermore, a sealing ring is provided on the top inner wall of the guide cone, and the sealing ring is located between the guide cone and the central tube.

[0014] Furthermore, the upper end face of the retrieval joint is provided with hanging teeth, and the lower end face is provided with a groove for fixing with the slip.

[0015] Furthermore, the limiting component adopts a limiting cone, which is made of aluminum alloy. Both the inner and outer walls of the limiting cone are equipped with sealing rings. The inner wall of the limiting cone is equipped with a threaded conical tooth structure, which cooperates with the outer wall teeth of the central tube.

[0016] Furthermore, a limit end cap is provided at the bottom of the central tube, and the limit end cap is connected to the piston.

[0017] Furthermore, a guide head is connected to the bottom of the lower connector of the rubber tube, and a guide hole is opened at the end of the guide head.

[0018] Furthermore, several grooves are evenly distributed on the contact surface between the central tube and the sealing rubber sleeve.

[0019] A working method based on the above-mentioned semi-permanent mechanical deployment and retrieval of soluble wellbore plugging bridge plugs includes:

[0020] The bridge plug is placed into the casing. The slips fix the bridge plug to the inner wall of the casing by inertia. The central tube is lifted, which drives the piston to squeeze the hydraulic oil in the lower connector of the rubber sleeve into the sealing rubber sleeve, causing the sealing rubber sleeve to expand and complete the setting seal.

[0021] The limiting component is dissolved, allowing the central tube to move axially. The sealing sleeve automatically contracts, grabs the retrieval joint, lifts the bridge plug, and completes the unsealing.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] This invention provides a semi-permanent mechanically deployable soluble wellbore plugging bridge plug. The bridge plug includes a deployment connector, a central tube, a retrieval connector, a guide cone, slips, and a setting mechanism. Limiting components are installed on the central tube and guide cone to facilitate axial displacement of the central tube. These limiting components are soluble, and through this limiting engagement, the setting and unsetting of the sealing mechanism are achieved. During setting, the slips, through inertia, fix the bridge plug to the inner wall of the casing. Lifting the central tube causes the piston to force hydraulic oil from the lower connector of the rubber sleeve into the sealing rubber sleeve, causing the sealing rubber sleeve to expand and completing the setting. At this time, the central tube and the limiting components are engaged and fixed. During unsetting, the limiting components are dissolved, allowing the central tube to move axially. The sealing rubber sleeve automatically contracts, and the bridge plug is retrieved by gripping the retrieval connector. This invention has a simple structure and principle, is easy to recycle, saves on operating costs, and provides high sealing pressure, thus assisting in oilfield oil and gas development and construction.

[0024] Preferably, the guide cone of the present invention has a guide hole and an air guide hole corresponding to the central tube. When the central tube is lifted, the guide hole and the air guide hole are connected to form an airflow channel, which can use airflow to clean the slip.

[0025] Preferably, the central tube and the central plug of the present invention are fixed to the delivery connector by means of a pin, and the central plug is used to block the flow in the center; during the delivery of the bridge plug, the pin is sheared by inertia, which facilitates the separation of the delivery connector from the central tube and the central plug.

[0026] Preferably, a sealing ring is provided on the inner wall of the top of the guide cone of the present invention to seal the annular space gap between the guide cone and the central tube.

[0027] Preferably, the upper end face of the retrieval connector of the present invention is provided with hanging reverse teeth to facilitate efficient retrieval during unsealing; the lower end face is provided with a groove to facilitate fixed connection with the slip.

[0028] Preferably, the limiting component of the present invention is a limiting cone made of aluminum alloy. The aluminum alloy material can dissolve in high-concentration salt water. The threaded conical tooth structure is designed to cooperate with the outer wall teeth of the central tube to achieve setting and unsealing. At the same time, sealing rings are provided on both the inner and outer walls of the limiting cone to ensure an effective sealing effect between the limiting cone and the central tube and the guide cone.

[0029] Preferably, a limiting end cap is provided at the bottom of the central tube of the present invention, and the limiting end cap is in contact with the piston, which plays a role in axially limiting the piston and improving the reliability of the bridge plug during operation.

[0030] Preferably, the bottom of the lower connector of the rubber tube of the present invention is connected to a guide head, and a guide hole is opened at the end of the guide head; the guide head plays a guiding role when the bridge plug is put in, and in addition, when the limiting member is dissolved, the liquid can be smoothly discharged from the guide hole of the guide head.

[0031] Preferably, the present invention has several grooves on the contact surface between the central tube and the sealing tube, which facilitates the introduction of hydraulic oil from the lower connector of the tube into the sealing tube.

[0032] This invention also provides a method for semi-permanent mechanically deployed and retrieved soluble wellbore plugging bridge plugs. Based on the aforementioned semi-permanent mechanically deployed and retrieved soluble wellbore plugging bridge plugs, this method utilizes the hydraulic setting principle to expand the rubber sleeve and create a medium flow sealing effect. This method uses inertial force to eject the slips, setting and gripping the casing to form a bridge plug load-bearing mechanism. During unsealing, the retrieval is achieved by dissolving the limiting element and lifting the retrieval joint, realizing step-by-step unsealing and retrieval. This method enables bridge plug recovery, saves operating costs, and features high sealing pressure and easy recovery, making it highly valuable for widespread application in oilfield oil and gas development and construction. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the specific embodiments of the present invention, the drawings used in the description of the specific embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0034] Figure 1 This is a schematic diagram of the structure of a semi-permanent mechanically deployed soluble wellbore plug provided in an embodiment of the present invention;

[0035] Figure 2 for Figure 1 AA section view;

[0036] Figure 3 for Figure 1 BB section view;

[0037] Figure 4 for Figure 1 CC section view;

[0038] Figure label:

[0039] Drop-1; Pin-2; Retrieval-3; Guide cone-4; Center tube-5; Center plug-6; Slip-7; Limit cone-8; Upper connector of rubber tube-9; Sealing rubber tube-10; Lower connector of rubber tube-11; Piston-12; Limit end cap-13; Guide head-14. Detailed Implementation

[0040] To make the technical problems solved by the present invention, the technical solutions, and the beneficial effects clearer, the following specific embodiments provide a further detailed description of the present invention. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of the invention.

[0041] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0042] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0043] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0044] In the description of the embodiments of the present invention, it should be noted that if terms such as "upper," "lower," "horizontal," or "inner" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of the invention is in use, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. Furthermore, terms such as "first" and "second" are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0045] Furthermore, the use of the term "horizontal" does not imply that the component must be absolutely horizontal, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0046] In the description of the embodiments of the present invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention according to the specific circumstances.

[0047] The present invention will now be described in further detail with reference to the accompanying drawings:

[0048] Example

[0049] Because existing bridge plug structures are prone to getting stuck in the casing after setting, making retrieval difficult, this embodiment provides a semi-permanent mechanically deployable soluble wellbore plugging bridge plug to address these technical problems. The specific structure is as follows: Figure 1 As shown, it includes:

[0050] The components are: 1. Drop connector; 2. Pin; 3. Retrieval connector; 4. Guide cone; 5. Central tube; 6. Central plug; 7. Slip; 8. Limiting cone; 9. Upper connector of rubber tube; 10. Sealing rubber tube; 11. Lower connector of rubber tube; 12. Piston; 13. Limiting end cap; and 14. Guide head. The specific structure is as follows:

[0051] The delivery connector 1 is a solid cylindrical structure with a groove at the upper end for easy gripping and fixing by the delivery tool. The lower end is fixed to the central tube 5 and the central plug 6 by a pin 2. When the delivery tool is lowered and repeatedly lifted up and down, the inertial force shears the pin 2 to detach the delivery connector 1 from the central tube 5 and the central plug 6. The central tube 5 and the central plug 6 are connected by the pin 2 when they are detached, and their end faces are flush.

[0052] The central tube 5 and the guide cone 4 are installed concentrically and connected by a clearance fit. The upper end of the guide cone 4 has two sealing grooves and is fitted with O-rings to seal the annular gap between the guide cone 4 and the central tube 5. A retrieval connector 3 is concentrically installed on the outside of the guide cone 4, also connected by a clearance fit. The upper end face of the retrieval connector 3 is designed with hanging teeth for retrieval tools to grip. The lower end face of the retrieval connector 3 is machined with grooves for installing four circumferential slips 7, which are attached to the inclined surface of the guide cone 4. When deployed, the retrieval joint 3 and the slip 7 move downwards due to inertia, penetrating the gap between the inclined surface of the guide cone 4 and the inner wall of the casing to form a force-bearing seat. A limiting cone 8, made of aluminum alloy (or other soluble material), is installed between the guide cone 4 and the central tube 5. The limiting cone 8 has a sealing groove on both its inner and outer walls and is fitted with an O-ring. The inner wall of the limiting cone 8 is designed with an internal threaded conical tooth structure, which can mesh with the teeth on the outer wall of the central tube 5 during the lifting and seating process.

[0053] The guide cone 4 is equipped with a rubber tube upper connector 9, which is a cylindrical structure. The lower end is interference-fitted with the sealing rubber tube 10. The sealing rubber tube 10 and the rubber tube lower connector 11 are also interference-fitted. A piston 12 is installed inside the rubber tube lower connector 11 and between it and the central tube 5. Before use, hydraulic oil is injected into the hole of the rubber tube lower connector 11 to seal the hole. During setting, the central tube 5 drives the piston 12 to lift and squeeze the hydraulic oil, which is introduced into the inner wall of the sealing rubber tube 10 to squeeze the sealing rubber tube 10 to expand and seal the annulus. The piston 12 is axially limited by the threaded connection between the limiting end cap 13 and the central tube 5, which locks it axially. The rubber tube lower connector 11 is threadedly connected to the guide head 14. The end of the guide head 14 has an opening for guiding the injection and discharging the liquid after dissolving the limiting cone 8.

[0054] Figure 2 As shown, as a preferred technical solution, the central tube 5 and the central plug 6 are locked together by the pin 2, with axial and circumferential limits, to ensure that the two cylindrical structures move together during the lifting of the seat seal.

[0055] Figure 3 As shown, as a preferred technical solution, the slip 7 is arranged in 4 groups with a circumferential interval of 90°, the inner wall is fitted with the conical surface of the guide cone 4, and the outer wall is parallel to the tool axis section; the outer wall of the end of the slip 7 is machined with teeth for biting into the inner wall of the sleeve and setting the seal to bear the force.

[0056] Figure 4 As shown, as a preferred technical solution, the contact surface between the central tube 5 and the sealing tube 10 is machined with an outer surface groove, arranged at 90° circumferentially, for introducing the hydraulic oil inside the lower connector 11 of the tube into the inner wall cavity of the sealing tube 10.

[0057] The specific working principle is as follows:

[0058] During setting, the deployment tool grabs the deployment connector 1 and uses a steel wire to hoist it deep into the wellbore. When it is about to reach the target depth, the winch is accelerated to lower it, and then suddenly braked to shear the pin 2. At the same time, relying on inertial force, the retrieval connector 3, guide cone 4, and slips 7 extend to form an annular setting.

[0059] During unsealing, a high-concentration brine is injected into the wellbore. The brine flows into the guide cone 4, dissolving the limiting cone 8 and releasing the axial constraint of the central tube 5. This is the core inventive point of this invention. The retrieval tool grabs the upper end face of the retrieval joint 3 and lifts the retrieval joint 3, along with the slip 7. At this time, the guide cone 4 has guide holes machined at 90° circumferential intervals on its conical surface, which communicate with the air guide hole of the central tube 5 to form an airflow to flush the slip 7, facilitating the lifting and unsealing. This is also one of the inventive points of this invention.

[0060] In other words, during the setting process, the delivery tool is connected to the delivery connector 1, the central tube 5, and the central plug 6, while the retrieval connector 3, the guide cone 4, and the slip 7 are axially movable parts that are thrown out of the setting due to inertial force.

[0061] During unsealing, acid is injected downhole. After the limiting cone 8 is submerged in the acid, it corrodes and dissolves. At this time, the axial limiting of the central tube 5 is canceled, and the guide cone 4 and slip 7 move upward to release the slip 7, thus achieving unsealing.

[0062] In summary, this invention provides a semi-permanent mechanically deployed soluble wellbore plugging bridge plug and its method. A tubular deployment connector is provided inside the casing, with a shear pin connecting the deployment connector to the central tube. A central plug is located inside the central tube, and a retrieval connector is located externally. A guide cone is installed inside the retrieval connector, with a slip at the lower part. An alloy limiting cone is installed inside the guide cone, and its lower end is threaded to the upper connector of the rubber sleeve. A rubber sleeve is installed at the center of the upper and lower connectors of the rubber sleeve. The rubber sleeve expands radially under the pressure of hydraulic oil inside the lower connector. A piston with a sealing ring is installed between the lower connector and the central tube. As the central tube is lifted, the piston compresses the hydraulic oil, expanding the rubber sleeve. A guide head with an opening is threaded at the bottom of the tool. The bridge plug can be deployed using a steel wire to seal the space inside the casing, forming a tight and load-bearing seal. Unsealing is achieved by injecting high-concentration brine to dissolve the limiting cone, creating axial breakage, and lifting to release the slip and rubber sleeve. It can be repeatedly deployed and reused.

[0063] The above embodiments are merely one of the implementation methods for achieving the technical solution of the present invention. The scope of protection claimed by the present invention is not limited to this embodiment, but also includes any variations, substitutions and other implementation methods that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention.

Claims

1. A semi-permanent mechanically cast and salvaged soluble wellbore plugging bridge plug, characterized in that: It comprises a launching joint (1), a salvaging joint (3), a guide cone (4), a center pipe (5), a slip (7) and a setting mechanism; The launching joint (1) is detachably connected to the center tube (5); the guide cone (4) is sleeved on the outside of the center tube (5); the salvage joint (3) and the slip (7) are both sleeved on the outside of the guide cone (4), and the bottom of the salvage joint (3) is connected to the top of the slip (7); a stopper matched with the center tube (5) is provided between the guide cone (4) and the center tube (5), and the stopper is made of a soluble material; the bottom of the guide cone (4) is connected to the setting mechanism, and the setting mechanism is sleeved on the outside of the center tube (5); The sealing mechanism comprises a rubber sleeve upper joint (9), a sealing rubber sleeve (10) and a rubber sleeve lower joint (11) which are connected in sequence, and the rubber sleeve upper joint (9) is connected to the bottom of the guide cone (4); A piston (12) is arranged between the lower joint (11) of the rubber cylinder and the central tube (5); the piston (12) is connected to the central tube (5).

2. A semi-permanent mechanically cast and salvaged soluble wellbore plugging bridge plug according to claim 1, characterized in that: A plurality of guide holes are opened on the circumference of the cone surface of the guide cone (4), and the guide holes are evenly distributed; corresponding air guide holes are opened on the central tube (5); when the central tube (5) is lifted, the guide holes are connected with the air guide holes to form an air flow channel.

3. A semi-permanent mechanically cast and salvaged soluble wellbore plugging bridge plug according to claim 1, characterized in that: A central plug (6) is inserted into the central tube (5); the central tube (5) and the central plug (6) are connected to the delivery joint (1) via a pin (2).

4. A semi-permanent mechanically cast and salvaged soluble wellbore plugging bridge plug according to claim 1, characterized in that: A sealing ring is provided on the inner wall of the top of the guide cone (4), and the sealing ring is located between the guide cone (4) and the central tube (5).

5. The semi-permanent mechanically cast and salvaged soluble wellbore plugging bridge plug according to claim 1, characterized in that: The upper end surface of the fishing joint (3) is provided with hanging inverted teeth, and the lower end surface is provided with a groove fixed with the slip (7).

6. A semi-permanent mechanically cast and salvaged soluble wellbore plugging bridge plug according to claim 1, characterized in that: The limiting member adopts a limiting cone (8), which is made of aluminum alloy. The inner wall and outer wall of the limiting cone (8) are both provided with sealing rings; the inner wall of the limiting cone (8) is provided with a threaded conical tooth structure, which matches with the outer wall teeth of the central tube (5).

7. The semi-permanent mechanically cast and salvaged soluble wellbore plugging bridge plug according to claim 1, characterized in that: A limiting end cover (13) is arranged at the bottom of the central tube (5), and the limiting end cover (13) is connected to the piston (12).

8. The semi-permanent mechanically cast and salvaged soluble wellbore plugging bridge plug according to claim 1, characterized in that: The bottom of the rubber cylinder lower joint (11) is connected with a guide head (14), and a guide hole is formed at the end of the guide head (14).

9. A semi-permanent mechanically cast and salvaged soluble wellbore plugging bridge plug according to claim 1, characterized in that: A plurality of grooves are evenly arranged on the contact surface between the central tube (5) and the sealing rubber tube (10).

10. A working method for semi-permanent mechanical casting and catching of soluble wellbore plugging bridge plugs according to any one of claims 1 to 9, characterized in that: include: The bridge plug is placed into the casing, and the slips (7) fix the bridge plug on the inner wall of the casing by inertia, and the center tube (5) is lifted, driving the piston (12) to squeeze the hydraulic oil in the lower joint (11) of the rubber cylinder into the sealing rubber cylinder (10), so that the sealing rubber cylinder (10) expands, and the sealing is completed; The limiting piece is dissolved, so that the central tube (8) can move axially, the sealing rubber tube (10) automatically shrinks, the salvage joint (3) is grasped, and the bridge plug is lifted up to complete the unsealing.

Images