A fishable plug, a fishing method and a downhole packoff plug system

Abstract

The present application relates to oil and gas operation tool technical field, and discloses a kind of fishable packer, comprising: setting assembly, for forming setting area between the inner wall of the packer;Locking assembly is arranged on the setting assembly, for locking the setting assembly with the packer;Unlocking assembly includes differential pressure balance mechanism and driving mechanism, the differential pressure balance mechanism is used to adjust the internal pressure of the setting area, and the driving mechanism is used to drive the locking assembly and the packer is separated from each other.The purpose of the present application is to solve the problem that the setting function and the interlayer isolation function of the existing setting tool are separated from each other, and the single-trip string cannot independently complete the setting and recovery operation.

Description

Technical Field

[0001] This invention relates to the field of oil and gas operation tools, specifically to a deployable plug, a deployment method, and a downhole sealing and plugging system. Background Technology

[0002] In well completion and workover operations in oil and gas fields, the widespread application of packers is crucial for stabilizing the downhole working environment. Currently, for large-size hydraulic packers, the industry commonly uses methods such as connecting the lower end of the packer to a shear ball seat for pressure buildup, wireline insertion for pressure buildup, or using the tubing string to carry the positioning seal to achieve packer setting. These techniques mainly rely on establishing a temporary seal inside the tubing string to trap fluid and generate the required high-pressure hydraulic differential, thereby prompting the packer to complete the setting action.

[0003] However, traditional setting tools often cannot simultaneously meet the dual requirements of hydraulic setting and long-term formation isolation. For example, using shear ball seats not only generates severe shocks, damaging the entire production tubing and wellhead equipment, but also permanently reduces the tubing's inner diameter. When using wireline plugs or positioning seals, the tool must be removed after setting, and if subsequent well completion of the upper section is required, the plugging tool must be run again to isolate the formation. This separation of setting and isolation functions means that a single tubing run cannot operate independently in a closed loop, significantly increasing the number of trips and overall construction costs. Furthermore, the cumbersome alternating procedures severely restrict on-site operational efficiency. Summary of the Invention

[0004] The purpose of this invention is to solve the problem that the setting function and interlayer isolation function of existing setting tools are separated, and a single tubing string cannot independently complete the setting and retrieval operations. Therefore, this invention proposes a drop-and-retrieve plug, a drop-and-retrieve method, and a downhole isolation plug system.

[0005] In a first aspect, embodiments of the present invention provide a retrieving blockage device, comprising: A setting assembly for forming a setting region between itself and the inner wall of the packer; A locking component, disposed on the setting assembly, is used to lock the setting assembly to the packer; The unlocking component includes a differential pressure balancing mechanism and a drive mechanism. The differential pressure balancing mechanism is used to adjust the internal pressure of the setting area, and the drive mechanism is used to drive the locking component to disengage from the packer.

[0006] In one embodiment, the outer wall of the setting assembly has a protrusion, and when the locking assembly moves to the protrusion, it locks the locking assembly to the packer through the protrusion.

[0007] In one embodiment, the outer wall of the sealing assembly forms a first recess and a second recess, the first recess and the second recess being located on opposite sides of the protrusion, and the locking assembly is used to lock the packer when it moves from the first recess to the protrusion, and to unlock the packer when it moves from the protrusion to the second recess.

[0008] In one embodiment, the locking component includes: A sliding element is movably disposed on the outer wall of the sealing assembly; A locking block, connected to the sliding member, has a protrusion for pushing the locking block toward the inner wall of the packer so that the locking block abuts against the packer; The elastic element has its two ends connected to the outer walls of the sliding element and the seat assembly, respectively.

[0009] In one embodiment, the setting assembly includes a transmission tube having a pressure transmission channel communicating with the setting region.

[0010] In one embodiment, the differential pressure balancing mechanism includes: A balance hole is formed on the setting assembly; A sealing element is connected to the end of the transmission tube. The sealing element is fixed inside the setting assembly by a first shear pin and is used to block the balance hole.

[0011] In one embodiment, the drive mechanism includes: The shear sleeve is fixed inside the setting assembly by a second shear pin. The outer wall of the shear sleeve is provided with an avoidance groove, and the inner wall of the shear sleeve is provided with a force-bearing groove. A cam block is disposed at the seat assembly. The cam block is used to abut against the shear sleeve and the slider when it moves to the outside of the clearance groove, and to release the abutment against the shear sleeve and the slider when the cam block moves into the clearance groove.

[0012] In one embodiment, the inner wall of the slider is provided with a third recess, and when the locking block is located in the protrusion, the third recess abuts against the cam block.

[0013] Secondly, embodiments of the present invention provide a method for retrieving a retrievable blockage device, comprising the following steps: Setting and sealing stage: The plug is placed into the packer, and the locking assembly is locked to the packer; the setting pressure is transmitted to the packer through the setting assembly, so that the packer is set in the wellbore; Salvage and recovery phase: Apply load to the unlocking component to activate the differential pressure balancing mechanism to balance the internal and external pressures of the sealing area; activate the drive mechanism to release the locking component from the packer; remove the unlocked plug from the packer.

[0014] Thirdly, embodiments of the present invention provide a downhole sealing and plugging system, comprising: Packers are used to set inside the wellbore to achieve interlayer isolation; A removable blocker is provided, which is detachably disposed within the packer.

[0015] Compared with the prior art, the technical solution of this application has the following beneficial technical effects: In this invention, the setting assembly of the retrievable plug is located inside the packer and forms a setting area between it and the inner wall of the packer. While achieving hydraulic setting of the packer, interlayer pressure isolation is also formed. The locking assembly locks the setting assembly to the packer, allowing the plug to remain stably in the packer for a long time, continuously providing a stable interlayer isolation environment for well completion operations in the upper section. The pressure differential balancing mechanism in the unlocking assembly can adjust the pressure in the setting area before retrieval, effectively balancing the annular pressure differential above and below the plug, eliminating suction resistance during retrieval, and ensuring smooth and reliable subsequent unlocking and retrieval operations. The drive mechanism drives the locking assembly to disengage from the packer after applying a load, achieving smooth retrieval of the plug and restoring the full bore of the tubing string. This completely avoids the problems of damage to the production tubing string and permanent reduction of the inner bore caused by excessive shear impact force in the traditional shear ball seat method. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall connection structure of the blocker of the present invention; Figure 2 This is a schematic diagram of the connection structure between the locking component and the protrusion of the present invention; Figure 3 This is a schematic diagram of the connection structure of the drive mechanism of the present invention; Figure 4 This is a schematic diagram of the connection structure of some sealing components of the present invention; Figure 5 This is a schematic diagram of the connection structure of the differential pressure balancing mechanism of the present invention; Figure 6 This is a schematic diagram of the connection structure between the plug and the packer of the present invention.

[0017] In the diagram: 1. Sealing assembly; 11. Transmission pipe; 11a. Pressure transmission channel; 12. Central pipe; 13. Connector; 14. Sealing assembly; 141. First sealing short circuit; 142. First seal; 143. Connecting pipe; 144. Second sealing short circuit; 145. Second seal; 2. Packer; 3. Locking assembly; 31. Sliding element; 311. Third recess; 32. Locking block; 33. Elastic element; 4. Unlocking assembly; 41. Differential pressure balancing mechanism; 411. Balancing hole; 412. Sealing element; 413. First shearing pin; 42. Drive mechanism; 421. Shearing sleeve; 421a. Clearance groove; 421b. Force groove; 422. Second shearing pin; 423. Cam block; 5. Protrusion; 6. First recess; 7. Second recess. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] According to a first aspect of this application, this application provides a retrieving blockage device, such as... Figures 1 to 6 As shown, its overall structure includes: a setting assembly 1, used to form a setting area between itself and the inner wall of the packer 2. The setting assembly 1 serves as the main supporting structure of the plugger. After being inserted into the inner cavity of the packer 2, the outer wall of the setting assembly 1 and the inner wall of the packer 2 form a closed setting area through a sealing fit. This setting area withstands hydraulic pressure from inside the tubing during setting operations. This pressure acts on the rubber sleeve chamber of the packer 2, causing the rubber sleeve to expand radially and tightly adhere to the well wall or casing, thereby achieving interlayer isolation. Effective sealing of the setting area is fundamental to the entire plugger's setting and plugging functions. Furthermore, the setting assembly 1 also includes a central tube 12, which is the main skeleton structure of the plugger, used to support and connect various functional components. The central tube 12 passes through the packer 2, and its two ends are respectively connected to a connector 13 and a sealing assembly 14. Locking component 3, disposed on setting component 1, is used to lock setting component 1 to packer 2. Locking component 3 employs a locking mechanical structure, which, after the plug is inserted into packer 2 and reaches the predetermined position, forms a reliable mechanical lock with the inner wall positioning structure of packer 2, thereby preventing the plug from accidentally dislodging during operation due to formation pressure fluctuations or tubing vibration. This locking method utilizes the principle of elastic energy storage to ensure the lock block is ultimately and reliably locked.

[0020] The unlocking component 4 includes a differential pressure balancing mechanism 41 and a drive mechanism 42. The differential pressure balancing mechanism 41 adjusts the internal pressure of the setting area; that is, during the retrieval and recovery phase, the action of the differential pressure balancing mechanism 41 balances the internal pressure of the setting area with the external annular pressure, eliminating the differential pressure resistance of the plug and preventing the suction effect caused by the differential pressure, ensuring a smooth and reliable recovery process. The drive mechanism 42 drives the locking component 3 to disengage from the packer 2; that is, after differential pressure balancing is completed, the action of the drive mechanism 42 releases the mechanical locking relationship between the locking component 3 and the packer 2, restoring the plug to a detachable state, facilitating the removal of the entire plug from the packer 2 using retrieval tools.

[0021] In some embodiments of this application, the outer wall of the setting assembly 1 forms a protrusion 5, such as... Figure 2 As shown, the protrusion 5 is arranged in a ring shape, and the two end faces have inclined transition areas. When the locking component 3 moves to the protrusion 5, it locks the locking component 3 and the packer 2 through the protrusion 5.

[0022] Specifically, the protrusion 5 is disposed on the outer wall of the setting assembly 1, protruding relative to the outer wall surface in the radial direction of the setting assembly 1. When the locking assembly 3 slides axially on the outer wall of the setting assembly 1 to the position of the protrusion 5, the protruding profile of the protrusion 5 forces the locking member in the locking assembly 3 to undergo radial displacement toward the inner wall of the packer 2, until the locking member abuts and locks against the stepped surface of the positioning structure such as the positioning sleeve on the inner wall of the packer 2. Thus, the protrusion 5 essentially acts as a radially pushing cam surface, converting axial movement into radial locking force, so that the entire locking process does not require an additional external power source, and can automatically complete the locking action solely by the axial movement during the packer delivery process.

[0023] In other embodiments of this application, the cross-sectional profile of the protrusion 5 can be designed as a gradually changing slope transition or an arc transition to reduce the axial resistance of the locking component 3 when passing through the protrusion 5, making the locking action smoother.

[0024] In some embodiments of this application, the outer wall of the setting assembly 1 forms a first recess 6 and a second recess 7, such as... Figure 1 and Figure 2 As shown, the first recess 6 and the second recess 7 are located on both sides of the protrusion 5, and the locking component 3 is used to lock the packer 2 when it moves from the first recess 6 to the protrusion 5, and to unlock the packer 2 when it moves from the protrusion 5 to the second recess 7.

[0025] The first recess 6 is located upstream of the protrusion 5, and the second recess 7 is located downstream of the protrusion 5. In the initial state of the plug delivery phase, the locking component of the locking assembly 3 is located within the first recess 6. At this time, the locking component is retracted within the outer wall contour of the setting assembly 1, and the overall outer diameter of the plug is consistent, allowing it to pass smoothly through the inner cavity of the packer 2 without interference. When the plug reaches the preset position, the locking assembly 3 moves along the outer wall of the setting assembly 1 from the first recess 6 towards the protrusion 5. The locking component expands outward under the radial pushing action of the protrusion 5, abutting against the inner wall positioning structure of the packer 2, thus completing the locking.

[0026] During the salvage and recovery phase, after the drive mechanism 42 is activated, the locking component 3 continues to move along the outer wall of the setting component 1 from the protrusion 5 towards the second concave portion 7. Guided by the concave space of the second concave portion 7, the locking component retracts inward, disengaging from the contact relationship with the positioning structure of the inner wall of the packer 2, thus completing the unlocking. Therefore, the protrusion 5, together with the first concave portion 6 and the second concave portion 7 on both sides, constitute a set of guide structures with varying contours. The axial displacement of the locking component 3 within different contour ranges achieves a three-state switching of "retraction—locking—retraction".

[0027] In some embodiments of this application, the locking component 3 includes a slider 31, movably disposed on the outer wall of the sealing component 1. For example... Figure 1 and Figure 2 As shown, the sliding member 31 has a sleeve-like structure, which is coaxially sleeved on the outer peripheral surface of the setting assembly 1 and can slide freely along the axial direction of the setting assembly 1. A sliding fit surface is formed between the inner wall of the sliding member 31 and the outer wall of the setting assembly 1 to ensure the motion stability and coaxiality of the sliding member 31 during axial movement.

[0028] Locking block 32 is connected to sliding member 31. Locking block 32 is mounted on sliding member 31. In this application, locking block 32 is through-hole disposed on sliding member 31 and moves axially along the setting assembly 1 together with sliding member 31. Protrusion 5 is used to push locking block 32 toward the inner wall of packer 2 so that locking block 32 abuts against packer. When sliding member 31 moves locking block 32 to the area where protrusion 5 is located, the protruding profile of protrusion 5 pushes locking block 32 toward the inner wall of packer 2 through radial thrust, so that the outer end face of locking block 32 forms a reliable mechanical abutment with the positioning sleeve step surface on the inner wall of packer 2, preventing the plug from axially dislodging. Multiple sets of locking blocks 32 are typically arranged symmetrically along the circumference of setting assembly 1 to ensure uniform distribution of locking force and stability of locking.

[0029] The elastic element 33 has its two ends connected to the outer walls of the sliding element 31 and the setting assembly 1, respectively. Further, the protrusion 5, the first concave portion 6, and the second concave portion 7 are integrally formed on the connector 13 of the setting assembly 1. The connector 13 is connected to the end of the central tube 12, thus the protrusion 5 and its two concave structures are all located on the outer wall contour of the connector 13, forming an integral guide and positioning frame with the central tube 12. The two ends of the elastic element 33 are connected to the inner protrusion of the sliding element 31 and the end of the connector 13 of the setting assembly 1, respectively, so that the installation position of the elastic element 33 matches the movement trajectory of the locking assembly 3, ensuring that the direction of the elastic restoring force is consistent with the sliding direction of the sliding element 31. The elastic element 33 is preferably a spring with a pre-set elastic preload. During the delivery phase, the elastic element 33 is in an energy-storing state. During the unlocking phase, when the drive mechanism 42 releases its limit on the sliding element 31, the elastic restoring force of the elastic element 33 drives the sliding element 31 to move axially, causing the locking block 32 to slide from the protrusion 5 to the second concave portion 7, thereby completing the automatic unlocking. This energy storage and release mechanism ensures the reliability and certainty of the unlocking action.

[0030] In some embodiments of this application, such as Figure 1 and Figure 3 As shown, the setting assembly 1 includes a transmission pipe 11, which has a pressure transmission channel 11a communicating with the setting area.

[0031] The transmission pipe 11 is a key component in the setting assembly 1 that realizes the hydraulic transmission function. A pressure transmission channel 11a is provided on its pipe wall to connect the inner cavity of the transmission pipe 11 with the setting area, so that the setting pressure applied from inside the pipe can be transmitted to the rubber cylinder chamber of the packer 2 through the pressure transmission channel 11a.

[0032] Furthermore, the sealing assembly 14 includes a first sealing short connector 141, which is fixedly installed at the end of the central tube 12. The exterior of the first sealing short connector 141 is provided with a first sealing element 142 that fits against the inner wall of the packer 2. The sealing assembly 14 also includes a second sealing short connector 144, which is connected to the first sealing short connector 141 via a connecting tube 143. The exterior of the second sealing short connector 144 is provided with a second sealing element 145 that fits against the inner wall of the packer 2. The setting area is the area between the first sealing element 142 and the second sealing element 145, which is sealed by the upper and lower sets of sealing elements, forming a closed hydraulic chamber isolated from the external annulus. The transmission tube 11 is also located at the axis of the connecting tube 143.

[0033] The first sealing element 142 is preferably a vulcanized sealing assembly, which integrates the sealing rubber and metal skeleton through a vulcanization process. This assembly offers excellent sealing performance, withstands high temperatures and pressures from the formation, and is suitable for deep wells and high-temperature well conditions. The second sealing element 145 is preferably a sealing packing. Packing seals have good wear resistance and self-adaptability, compensating for minor deformations caused by temperature changes or pressure fluctuations. The two sets of sealing elements, of different types, work together to form a double sealing barrier, significantly improving the overall sealing reliability of the setting area.

[0034] A pressure transmission channel is also provided on the connecting pipe 143, which together with the pressure transmission channel 11a on the transmission pipe 11 forms a complete hydraulic transmission path. After the tool is lowered into the target section, the pressure is applied inside the tubing string, and the pressure is transmitted sequentially through the pressure transmission channel 11a on the transmission pipe 11 and the pressure transmission channel on the connecting pipe 143 to the rubber sleeve chamber of the packer 2. When the pressure reaches the set value, the rubber sleeve of the packer 2 expands radially and fits tightly against the well wall or casing, completing the setting.

[0035] In some embodiments of this application, the differential pressure balancing mechanism 41 includes a balancing hole 411 and a sealing element 412, wherein the balancing hole 411 is formed on the setting assembly 1. Figure 1 and Figure 5 As shown, specifically, the balancing hole 411 is opened on the second sealing short joint 144 of the setting assembly 1, and is a through hole structure that radially penetrates the pipe wall of the second sealing short joint 144. Since the lower boundary of the setting area is closed by the second seal 145, the balancing hole 411 is set at the second sealing short joint 144, which can directly connect the interior of the setting area with the external annulus after opening, so that the pressure on both sides can quickly reach equilibrium.

[0036] A sealing element 412 is connected to the end of the transmission pipe 11. The sealing element 412 is fixed inside the setting assembly 1 by a first shear pin 413 and blocks the balance hole 411. Under normal operating conditions, the sealing element 412 blocks the balance hole 411 to ensure the sealing integrity of the setting area and to ensure that pressure will not leak to the external annulus through the balance hole 411 during the hydraulic setting process. During the salvage and recovery stage, when an axial load is applied to the sealing element 412 by the recovery tool, and the first shear pin 413 reaches its set shearing value, the first shear pin 413 breaks. The sealing element 412 moves axially and moves away from the blocking position of the balance hole 411. The balance hole 411 then opens, and the high-pressure fluid inside the setting area communicates with the external annulus through the balance hole 411. The pressure difference is quickly eliminated, effectively preventing the suction effect and ensuring a smooth and safe recovery process.

[0037] The shear load of the first shear pin 413 is precisely designed, with a trigger threshold higher than the maximum axial force on the blocker under normal operating conditions to prevent false triggering during operation; at the same time, it is lower than the maximum applied load of the retrieval tool to ensure reliable triggering during retrieval. By reasonably setting the shear value of the first shear pin 413, precise and controllable triggering of the differential pressure balancing action can be achieved.

[0038] In some embodiments of this application, the drive mechanism 42 includes a shear sleeve 421, which is fixed to the setting assembly 1 by a second shear pin 422. For example... Figure 1 and Figure 3 As shown, the shear sleeve 421 is a tubular component. Under normal operating conditions, it is relatively fixed to the central tube 12 of the setting assembly 1 by the second shear pin 422, preventing axial movement. The outer wall of the shear sleeve 421 has a relief groove 421a, and the inner wall has a force-bearing groove 421b. The relief groove 421a is a groove structure opened along the outer wall of the shear sleeve 421, used to provide radial storage space for the cam block 423 during unlocking. The force-bearing groove 421b is located on the inner wall of the shear sleeve 421, used to engage with the lug structure on the top of the recovery tool during retrieval, to withstand the axial lifting load applied by the recovery tool. It should be noted that the recovery tool should be T-shaped. After extending into the force-bearing groove 421b of the shear sleeve 421, the lug extends outward to lock the force-bearing groove 421b, and then force can be applied to move the entire shear sleeve 421. The cam block 423 is installed in the setting assembly 1. Specifically, the cam block 423 is installed in the central tube 12 of the setting assembly 1. The central tube 12 has a corresponding through groove on its wall to allow the cam block 423 to have a certain degree of freedom of movement in the radial direction. At the same time, the through groove of the central tube 12 constrains and guides the axial displacement of the cam block 423.

[0039] In the locked state, when the cam block 423 moves to the outside of the clearance groove 421a, it abuts against the shear sleeve 421 and the slider 31 respectively. That is, the cam block 423 is in the solid wall area of ​​the shear sleeve 421 outside the clearance groove 421a, with its inner side abutting against the outer wall of the shear sleeve 421 and its outer side abutting against the inner wall of the slider 31, thus restricting the slider 31 to the current axial position and preventing the slider 31 from sliding axially in advance under the elastic force of the elastic member 33, thereby ensuring that the locking block 32 is stably maintained in the locked state at the protrusion 5.

[0040] During the unlocking phase, the retrieval tool applies an axial upward load to the shear sleeve 421 via the force groove 421b. When the load reaches the shearing value of the second shear pin 422, the second shear pin 422 breaks, and the shear sleeve 421 moves axially upward with the retrieval tool. When the cam block 423 moves into the clearance groove 421a, it releases the resistance to the shear sleeve 421 and the sliding member 31. The sliding member 31 can move axially relative to the outer periphery of the setting assembly 1. That is, after the shear sleeve 421 moves, the clearance groove 421a is aligned with the position of the cam block 423. The cam block 423 falls inward into the clearance groove 421a without radial external support, no longer constituting a radial limit on the sliding member 31. At this time, the elastic member 33 releases its elastic stored energy, driving the sliding member 31 to slide axially along the outer periphery of the setting assembly 1, causing the locking block 32 to move from the protrusion 5 to the second concave portion 7. The locking block 32 retracts radially, releasing the mechanical lock with the positioning sleeve of the packer 2, thus completing the unlocking.

[0041] In some embodiments of this application, such as Figure 3 As shown, the inner wall of the slider 31 is provided with a third recess 311. When the locking block 32 is located in the protrusion 5, the third recess 311 abuts against the cam block 423.

[0042] The third recess 311 is a recessed structure formed along the inner wall of the sliding member 31, so that when the locking block 32 is in the position of the protrusion 5, i.e., in the locked state, the third recess 311 is exactly aligned axially with the cam block 423 and forms an abutment fit. This abutment relationship has a dual function: firstly, after the cam block 423 is embedded in the third recess 311, it forms an axial positioning, restricting the axial movement of the sliding member 31, further enhancing the stability of the locked state, and preventing the locked state from being prematurely released due to downhole vibration or tubing load fluctuations; secondly, the third recess 311 provides radial accommodating space for the cam block 423, so that when the cam block 423 is outside the clearance groove 421a, it can simultaneously maintain radial abutment with the outer wall of the shear sleeve 421 and the inner wall of the sliding member 31, ensuring the reliability of the dual-sided limiting function.

[0043] When the unlocking action occurs and the cam block 423 falls into the clearance groove 421a, the cam block 423 disengages from the abutment relationship with the third inner recess 311, the sliding member 31 gains axial freedom, and completes axial displacement under the drive of the elastic member 33, thus achieving reliable unlocking.

[0044] According to a second aspect of this application, this application provides a method for retrieving a retrieving blockage device, comprising the following steps: Delivery and sealing phase: The plug is inserted into the packer 2, locking the locking assembly 3 to the packer 2. Specifically, during the initial insertion, the locking block 32 is located within the first recess 6 on the connector 13, within the outer contour of the setting assembly 1, and the overall outer diameter of the plug matches the inner hole of the packer 2, allowing for smooth insertion. When the plug reaches the preset position, the elastic force of the elastic element 33 drives the sliding element 31 to move the locking block 32 from the first recess 6 to the protrusion 5 on the connector 13. The locking block 32 is radially pushed out by the protrusion 5 and forms a mechanical lock with the positioning sleeve step surface of the inner wall of the packer 2, reliably engaging the one-way locking mechanism.

[0045] The setting pressure is transmitted to the packer 2 via the setting assembly 1, causing the packer 2 to set within the wellbore. After the tool is inserted into the well to the target section, pressure is applied inside the tubing string, and the pressure is transmitted sequentially through the pressure transmission channel 11a on the transmission pipe 11 and the pressure transmission channel on the connecting pipe 143 to the rubber sleeve chamber of the packer 2. When the pressure reaches the set value, the rubber sleeve of the packer 2 expands radially, tightly fitting against the well wall or casing, completing the setting. The plug forms inter-layer pressure isolation downhole, providing a stable operating environment for completion of the upper well section. After setting, the sealing ball is dropped into the ball seat of the hydraulic delivery tool, and pressure is applied until the hydraulic delivery tool shear pin breaks at the pressure value. The hydraulic delivery tool then detaches from the packer 2 and is retrieved from the wellbore, while the plug remains inside the packer 2.

[0046] Salvage and recovery phase: After well completion, a special recovery tool is lowered to the plugging position via coiled tubing or drill pipe.

[0047] A load is applied to the unlocking component 4, causing the differential pressure balancing mechanism 41 to activate and balance the internal and external pressures of the setting area. Specifically, an axial load is applied to the plugging component 412 using a recovery tool, shearing the first shear pin 413. The plugging component 412 moves downward, and the balance hole 411 on the second sealing short circuit 144 opens, allowing the high-pressure fluid inside the setting area to communicate with the external annulus. The pressure difference above and below the plug is quickly eliminated, effectively preventing the suction effect and ensuring a smooth and safe subsequent recovery process.

[0048] The drive mechanism 42 is activated to release the locking assembly 3 from the packer 2. Specifically, the recovery tool is lifted, and the lug at the top of the tool engages with the force groove 421b on the inner wall of the shear sleeve 421, applying an axial load to shear the second shear pin 422. The shear sleeve 421 moves axially, and the cam block 423, which passes through the central tube 12, falls into the clearance groove 421a, releasing the radial limit on the sliding member 31. The elastic member 33 elastically retracts to release the stored energy, pushing the sliding member 31 to slide axially along the outer wall of the joint 13, causing the locking block 32 to slide from the protrusion 5 to the second concave portion 7. The locking block 32 retracts radially, releasing the mechanical lock with the positioning sleeve of the packer 2.

[0049] Remove the unlocked plug from packer 2. Continuously lift the retrieval tool to detach the unlocked plug from packer 2, achieving full-bore restoration of packer 2. The entire retrieval process is safe and efficient.

[0050] The significant advantages of this retrieval method are: packer setting and plug locking can be completed in a single drilling run, and plug retrieval can be completed in a single drilling run, greatly reducing the number of drilling operations, significantly improving operational efficiency and reducing construction costs. The sequential operation of first balancing the differential pressure and then mechanically unlocking ensures the safety and reliability of the retrieval process.

[0051] According to a third aspect of this application, this application provides a downhole packing and plugging system, comprising: Packer 2 is used to set within the wellbore to achieve inter-layer isolation. Packer 2 is a hydraulically set packer with an internal rubber sleeve chamber. Under hydraulic pressure, the rubber sleeve expands radially and tightly fits against the wellbore wall or casing, achieving pressure isolation between upper and lower layers. The inner wall of packer 2 has a stepped positioning sleeve structure, such as... Figure 6 As shown, the locking assembly 3 is used to form a mechanical locking engagement with the retrievable blocker, ensuring that the blocker remains stably within the packer 2 during operation.

[0052] A retrievable plug is detachably installed inside the packer 2. The retrievable plug forms an unlockable mechanical connection with the packer 2 via a locking assembly 3. It forms a sealing fit with the inner wall of the packer 2 via the first seal 142 and the second seal 145 of the sealing assembly 14. After the packer 2 completes hydraulic setting, the plug continues to perform the plugging function of inter-layer pressure isolation, providing a stable operating environment for the upper well completion. After the upper well completion operation is completed, the unlocking assembly 4 is triggered by a special retrieval tool. First, the differential pressure resistance above and below the plug is eliminated by the differential pressure balancing mechanism 41. Then, the mechanical lock between the locking assembly 3 and the packer 2 is released by the drive mechanism 42, finally removing the plug from the packer 2 and restoring the full bore of the packer 2 to meet the needs of subsequent production.

[0053] This downhole packer and plugging system organically combines packer 2 with a drop-and-retrieve plug, realizing an integrated design for the entire process of "setting, plugging, and recovery". Compared with existing technologies, it eliminates the need for multiple drilling runs, resulting in high operational efficiency; it offers diverse sealing methods and strong adaptability; its full-bore design does not affect the inner diameter of the tubing string; and it features a differential pressure balance protection mechanism during recovery, ensuring safety and reliability. It possesses significant technical advantages and engineering application value.

[0054] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0055] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A retrieving blockage device, characterized in that, include: A setting assembly (1) is used to form a setting area between itself and the inner wall of the packer (2); A locking component (3) is disposed on the setting assembly (1) for locking the setting assembly (1) and the packer (2); The unlocking component (4) includes a differential pressure balancing mechanism (41) and a drive mechanism (42). The differential pressure balancing mechanism (41) is used to adjust the internal pressure of the sealing area, and the drive mechanism (42) is used to drive the locking component (3) to disengage from the packer (2).

2. The retrievable blockage device according to claim 1, characterized in that, The outer wall of the sealing assembly (1) forms a protrusion (5), and when the locking assembly (3) moves to the protrusion (5), it locks the locking assembly (3) and the packer (2) through the protrusion (5).

3. The retrievable blockage device according to claim 2, characterized in that, The outer wall of the sealing assembly (1) forms a first recess (6) and a second recess (7), the first recess (6) and the second recess (7) being located on both sides of the protrusion (5), and the locking assembly (3) being used to lock the packer (2) when it moves from the first recess (6) to the protrusion (5), and to unlock the packer (2) when it moves from the protrusion (5) to the second recess (7).

4. The retrievable blockage device according to claim 3, characterized in that, The locking component (3) includes: A sliding member (31) is movably disposed on the outer wall of the seat assembly (1); Locking block (32), connected to the sliding member (31), the protrusion (5) is used to push the locking block (32) toward the inner wall of the packer (2) so that the locking block (32) abuts against the packer (2). The elastic element (33) is connected at both ends to the outer wall of the sliding element (31) and the seat assembly (1), respectively.

5. The retrievable blockage device according to claim 1, characterized in that, The setting assembly (1) includes a transmission pipe (11), which is provided with a pressure transmission channel (11a) communicating with the setting area.

6. The retrievable blockage device according to claim 5, characterized in that, The differential pressure balancing mechanism (41) includes: A balance hole (411) is provided on the seat assembly (1); A sealing element (412) is connected to the end of the transmission pipe (11). The sealing element (412) is fixed inside the setting assembly (1) by a first shear pin (413) and is used to block the balance hole (411).

7. The retrievable blockage device according to claim 4, characterized in that, The drive mechanism (42) includes: The shear sleeve (421) is fixed inside the seat assembly (1) by the second shear pin (422). The outer wall of the shear sleeve (421) is provided with a relief groove (421a), and the inner wall of the shear sleeve (421) is provided with a force-bearing groove (421b). A cam block (423) is disposed at the seat assembly (1). The cam block (423) is used to abut against the shear sleeve (421) and the slider (31) respectively when it moves to the outside of the relief groove (421a), and to release the abutment against the shear sleeve (421) and the slider (31) when the cam block (423) moves into the relief groove (421a).

8. The retrievable blockage device according to claim 7, characterized in that, The inner wall of the sliding member (31) is provided with a third recess (311). When the locking block (32) is located in the protrusion (5), the third recess (311) abuts against the cam block (423).

9. A method for retrieving a retrieving blockage device, characterized in that, The method applied to the retrievable blocker as described in any one of claims 1 to 8 includes the following steps: Setting stage: The plug is placed into the packer (2) to lock the locking assembly (3) with the packer (2); the setting pressure is transmitted to the packer (2) through the setting assembly (1) to set the packer (2) in the wellbore; Salvage and recovery phase: Apply load to the unlocking component (4) to activate the differential pressure balancing mechanism (41) to balance the internal and external pressures of the sealing area; activate the driving mechanism (42) to release the locking component (3) from the packer (2); remove the unlocked packer from the packer (2).

10. A downhole sealing and plugging system, characterized in that, include: Packer (2) is used to be set inside the wellbore to achieve interlayer isolation; The retrievable blocker as described in any one of claims 1 to 8, wherein the retrievable blocker is detachably disposed within the packer (2).

Images