A packer

Abstract

This invention relates to the field of oil and gas well drilling and production technology, and discloses a packer comprising: a central tube having a flow channel for fluid passage; a rubber sleeve fitted over the central tube; a setting drive assembly fitted over the central tube and abutting against the rubber sleeve, the setting drive assembly including at least two drive members arranged in series along the axial direction, each drive member forming a hydraulic chamber communicating with the flow channel between itself and the central tube, each drive member being used to move axially when fluid is introduced into the hydraulic chamber and to compress the rubber sleeve; and a release assembly fitted over the central tube and abutting against the rubber sleeve, the release assembly being isolated from each of the hydraulic chambers. This packer can significantly reduce the risk of release failure.

Description

Technical Field

[0001] This invention relates to the field of oil and gas well drilling and production technology, specifically to a packer. Background Technology

[0002] In downhole operations such as stratified oil and gas field development, stratified fracturing, and acidizing, packers are the core tools for achieving inter-layer isolation. Hydraulically set and retrievable packers, with their stable setting pressure, reliable sealing, and reusability, are widely used in stratified operations of various well types. These packers typically use hydraulic pressure to drive the setting mechanism, pushing the rubber sleeve radially to expand, and an anchoring mechanism to maintain the setting state. After the operation, a corresponding release mechanism releases the anchor and retrieves the tool to restore normal wellbore access.

[0003] However, existing hydraulically set retrievable packers generally require a large release force to release after setting. In actual operations, there are often situations where the lifting force has reached the construction limit but the packer still cannot be released smoothly, causing the tool to remain downhole. This increases the difficulty and cost of subsequent retrieval operations and affects the safety and timeliness of the operation. Summary of the Invention

[0004] The purpose of this invention is to provide a packer to reduce the risk of unsealing failure.

[0005] An embodiment of the present invention provides a packer, comprising: A central tube, wherein a flow channel for fluid to pass through is provided inside the central tube; A rubber sleeve is fitted over the central tube; A setting drive assembly is sleeved outside the central tube and abuts against the rubber sleeve. The setting drive assembly includes at least two drive members arranged in series along the axial direction. Each drive member has a hydraulic chamber that communicates with the flow channel between it and the central tube. Each drive member is used to move axially when fluid is introduced into the hydraulic chamber and to compress the rubber sleeve. The unsealing component is sleeved outside the central tube and abuts against the rubber tube. The unsealing component is isolated from each of the hydraulic chambers so that the unsealing component does not bear the hydraulic pressure in the hydraulic chambers during the setting and pressurization process. The unsealing component is used to release the axial support on the rubber tube when it is lifted axially, so that the rubber tube retracts and the central tube is lifted and retracted.

[0006] In one embodiment, the setting drive assembly further includes a first inner cylinder and a second inner cylinder, the first inner cylinder being sleeved and fixed outside the central tube, and the second inner cylinder being coaxially connected to the end of the first inner cylinder away from the rubber tube; At least two of the driving components include a first driving component and a second driving component. The first driving component is slidably sleeved on the central tube, and the second driving component is slidably sleeved on the first inner cylinder. The first driving component and the second driving component are axially connected in series.

[0007] In one embodiment, radial protrusions are provided on the outer peripheral surfaces of both the first inner cylinder and the second inner cylinder; The first driving member, the central tube, and the protrusion of the first inner cylinder together form a first hydraulic cavity, and the second driving member, the first inner cylinder, and the protrusion of the second inner cylinder together form a second hydraulic cavity. The central tube has a first liquid channel connecting the flow channel and the first hydraulic chamber, and the first inner cylinder has a second liquid channel connecting the flow channel and the second hydraulic chamber.

[0008] In one embodiment, the seat drive assembly further includes a lower connector, a locking member, and a first shear pin. The lower connector is connected to the end of the second inner cylinder away from the first inner cylinder. The locking member is fixedly connected to the second drive member and connected to the lower connector through the first shear pin. The locking member is unidirectionally locked to the second inner cylinder.

[0009] In one embodiment, the unsealing component includes a connector and a retainer, both of which are sleeved on and connected to the central tube, and the retainer abuts against the rubber tube.

[0010] In one embodiment, the abutment includes: The upper guide ring is slidably sleeved on the central tube, one end of the rubber tube abuts against the upper guide ring, and the other end abuts against the driving member; A fixed sleeve is slidably fitted onto the central tube and connected to the upper guide ring, and a limiting part is provided at the end of the fixed sleeve away from the upper guide ring; A limiting ring is slidably sleeved on the outer periphery of the fixed sleeve, and the limiting ring can axially abut against the limiting part.

[0011] In one embodiment, the connector includes: A connecting sleeve is slidably disposed outside the central tube and connected to the limiting ring; A release ring is connected to the outer periphery of the central tube, and the connecting sleeve and the release ring are axially limited by a snap-fit ​​structure.

[0012] In one embodiment, the engaging structure includes: a plurality of annular grooves on the outer peripheral surface of the release ring, and an annular protrusion on the inner wall of the connecting sleeve; the release ring is a ring body with an axial opening and an axially extending slot along the circumference to form an elastic arm, the elastic arm being capable of radial deformation so that the annular protrusion disengages from the annular groove.

[0013] In one embodiment, the connector further includes an intermediate joint connected to the end of the central tube, and the intermediate joint is connected to the connecting sleeve via a second shear pin.

[0014] In one embodiment, the device further includes an elastic claw, an upper connector, and a piston. The elastic claw is located inside the connecting sleeve and engages with the intermediate connector. The upper connector is connected to the inner side of the elastic claw. The piston is connected to the elastic claw via a third shear pin.

[0015] Compared with the prior art, the technical solution of this application has the following beneficial technical effects: In terms of setting and sealing drive, this invention introduces a driving method in which multiple independent pressure-bearing units work together in series along the axial direction. Each pressure-bearing unit generates axial thrust synchronously under the same fluid pressure and the thrust is superimposed, enabling the rubber sleeve to achieve sufficient radial expansion and reliable sealing under relatively low supply pressure conditions. Compared with the traditional single-drive-cavity structure, this improves the setting and sealing drive efficiency and is beneficial for ensuring setting and sealing quality under complex well conditions.

[0016] Meanwhile, the entire unsealing mechanism does not intervene in the hydraulic pressurization circuit throughout the entire sealing operation. It remains in a state of no additional load throughout the entire sealing process, and the internally preset release force remains constant, not changing with the sealing pressure. This ensures that the actual lifting force required depends only on the initial design value of the unsealing mechanism itself, thereby controlling the release force at a predictably low level and significantly reducing the risk of unsealing failure. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall connection structure of the present invention; Figure 2 For the present invention Figure 1 Enlarged view of point A in the middle; Figure 3 For the present invention Figure 1 Enlarged view at point B in the middle; Figure 4 For the present invention Figure 1 Enlarged view at point C; Figure 5 For the present invention Figure 1 Enlarged view at point D; Figure 6 For the present invention Figure 1 Enlarged view at point E in the middle; Figure 7 This is a schematic diagram of the three-dimensional connection structure of the release ring of the present invention.

[0018] In the diagram: 1. Central tube; 2. Rubber sleeve; 3. Sealing drive assembly; 31. Drive component; 31a. First drive component; 31b. Second drive component; 32. First inner cylinder; 33. Second inner cylinder; 34. Lower connector; 35. Locking component; 36. First shearing pin; 4. Unsealing assembly; 41. Connecting component; 411. Connecting sleeve; 412. Release ring; 413. Intermediate connector; 414. Second shearing pin; 42. Supporting component; 421. Upper guide ring; 422. Fixing sleeve; 423. Limiting ring; 5. Elastic claw; 6. Upper connector; 7. Piston; 8. Third shearing pin. Detailed Implementation

[0019] 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.

[0020] The packer provided in this application is mainly used in downhole operations such as stratified production, stratified fracturing and acidizing in oil and gas fields to achieve reliable isolation between different producing layers. For example, the packer can be applied to stratified operations in different well types such as vertical wells, deviated wells, and shallow horizontal wells.

[0021] Reference Figures 1 to 7 In one embodiment of this application, a packer is provided, including a central tube 1, a rubber sleeve 2, a setting drive assembly 3, and a desealing assembly 4.

[0022] The central tube 1, serving as the load-bearing skeleton of the overall structure, runs axially through the packer and contains a flow channel for fluid passage. During the lowering operation, this flow channel acts as a hydraulic medium delivery channel, transferring the hydraulic fluid pumped from the ground to the various hydraulic chambers inside the packer, thereby providing a power source for the setting drive.

[0023] The rubber sleeve 2 is fitted around the outer periphery of the central tube 1, that is, the rubber sleeve 2 surrounds the outer wall surface of the central tube 1. The rubber sleeve 2 is an elastic sealing element, which can expand radially when subjected to axial compressive force, forming a tight contact with the inner wall of the sleeve, thereby achieving interlayer sealing.

[0024] It is understandable that there is a force conversion relationship between axial compression and radial expansion of the rubber sleeve 2: when the setting drive assembly 3 compresses the rubber sleeve 2 axially, the rubber material of the rubber sleeve 2 deforms and expands in the radial direction under the action of axial compression force, thereby forming an interference-sealed contact surface with the inner wall of the sleeve, achieving reliable interlayer isolation. For example, the rubber sleeve 2 can be made of elastomer materials with excellent high temperature resistance and oil resistance, such as hydrogenated nitrile rubber, fluororubber, or EPDM rubber, or it can be in the form of a multi-layered rubber sleeve assembly to improve sealing reliability and pressure resistance.

[0025] The setting drive assembly 3 is sleeved outside the central tube 1 and abuts against one end of the rubber sleeve 2. The setting drive assembly 3 includes at least two drive members 31 arranged in series along the axial direction. Each drive member 31 forms a hydraulic chamber communicating with the flow channel between itself and the central tube 1. When hydraulic fluid is pumped into the flow channel, the fluid enters each hydraulic chamber simultaneously. The hydraulic pressure in each hydraulic chamber acts simultaneously on the corresponding drive member 31. Each drive member 31 is used to move axially when fluid is introduced into the hydraulic chamber and to compress the rubber sleeve 2.

[0026] Understandably, compared to traditional single-chamber drive structures, the core advantage of multi-chamber series drive is that, under the same supply pressure conditions, the total driving force equals the sum of the axial thrust output by each hydraulic chamber, meaning the total driving force increases proportionally with the number of hydraulic chambers. This implies that without increasing the pump inlet pressure, a greater setting driving force can be obtained by increasing the number of hydraulic chambers, effectively improving setting driving efficiency and ensuring sufficient expansion and reliable sealing of the rubber sleeve 2 under complex well conditions.

[0027] For example, when two hydraulic chambers are provided, the total driving force is approximately twice that of a single-chamber structure; when a higher setting force is required, the number of drive components 31 can be increased to three or more to accommodate the different requirements of setting force for different well conditions.

[0028] The unsealing component 4 is sleeved outside the central tube 1 and abuts against the end of the rubber sleeve 2 away from the setting drive component 3. The unsealing component 4 is isolated from each hydraulic chamber, so that the unsealing component 4 does not bear the hydraulic pressure in the hydraulic chamber during the setting pressurization process. The unsealing component 4 is used to release the axial support on the rubber sleeve 2 when it is lifted axially, so that the rubber sleeve 2 retracts and the central tube 1 is lifted and retracted.

[0029] It should be noted that "the unsealing component 4 is isolated from each hydraulic chamber" in this application means that the unsealing component 4 is not located in the hydraulic pressurization circuit in terms of structural arrangement. On the entire path of the hydraulic fluid entering each hydraulic chamber from the flow channel and driving the drive component 31 to move, no part of the unsealing component 4 serves as a bearing surface or transmission surface of hydraulic force. Therefore, during the entire setting and pressurization process, the unsealing component 4 itself does not bear any hydraulic pressure from the hydraulic chamber.

[0030] In traditional hydraulically set retrievable packers, the release mechanism is often directly or indirectly mechanically coupled with the hydraulic pressurization circuit. For example, in traditional solutions, a slip anchoring structure is used. During the setting process, the slip is driven by hydraulic pressure to embed into the inner wall of the casing. The higher the setting pressure, the deeper the slip is embedded and the greater the anchoring force. This results in a significant increase in the release force required for release as the setting pressure increases. In actual operations, it often happens that the lifting force has reached the construction limit (e.g., tens of tons or even higher) but the packer still cannot be released smoothly, which seriously affects the safety and timeliness of the operation.

[0031] This application completely isolates the release component 4 from the hydraulic pressurization circuit, ensuring that the preset release force (i.e., the shear force or release force required to trigger release) within the release component 4 remains constant and does not change with the setting pressure. In other words, regardless of the hydraulic pressure pumped in during the setting process, the stress state of the release component 4 remains unaffected, and the lifting force required for release depends only on the initial design shear value of the shear pin inside the release component 4. For example, the release force required for release in this application can be controlled at approximately 1500 LBS, far lower than the tens of tons of release force required by traditional slip-anchored packers. This fundamentally avoids the problem of excessive release resistance caused by the reverse superposition of hydraulic pressure, significantly reducing the risk of release failure and improving operational safety and timeliness.

[0032] Furthermore, the packer of this application does not have a slip structure, and the entire setting process does not involve a slip anchoring process, thereby reducing the complexity of the workflow. At the same time, since there is no process of slips embedding into the inner wall of the casing, the damage to the casing during unsealing is significantly reduced, which is beneficial to the long-term integrity maintenance of the casing.

[0033] In one embodiment of this application, the setting drive assembly 3 further includes a first inner cylinder 32 and a second inner cylinder 33. The first inner cylinder 32 is sleeved and fixed to the outer periphery of the central tube 1, and the second inner cylinder 33 is coaxially connected to the end of the first inner cylinder 32 away from the rubber sleeve 2. At least two drive members 31 include a first drive member 31a and a second drive member 31b. The first drive member 31a is slidably sleeved on the central tube 1, and the second drive member 31b is slidably sleeved on the first inner cylinder 32. The first drive member 31a and the second drive member 31b are axially connected in series.

[0034] Reference Figure 5 and Figure 6As shown, the first inner cylinder 32 is fixedly sleeved on the outer periphery of the central tube 1, serving as the guide and support base for the second drive component 31b, and also participating in enclosing the hydraulic cavity. The second inner cylinder 33 is coaxially connected to the end of the first inner cylinder 32 away from the rubber sleeve 2, that is, the second inner cylinder 33 is located below the first inner cylinder 32 (with the direction of the packer entering the wellbore as a reference), used to further define the boundary of the hydraulic cavity and to undertake the axial limiting function of the stroke of the second drive component 31b.

[0035] The first driving component 31a is slidably sleeved on the outer periphery of the central tube 1 and can slide axially along the central tube 1 under hydraulic pressure. Its end facing the rubber cylinder 2 directly abuts against the rubber cylinder 2, which is equivalent to the function of the lower guide ring, transmitting axial thrust to the rubber cylinder 2. At the same time, the first driving component 31a is provided with a first inner retaining ring, and the first driving component 31a is connected to the lower part of the rubber cylinder 2 through the first inner retaining ring. The second driving component 31b is slidably sleeved on the outer periphery of the first inner cylinder 32 and is axially connected in series with the first driving component 31a. Under hydraulic pressure, the two components work together to generate axial thrust, which is superimposed sequentially to jointly drive the rubber cylinder 2 to compress.

[0036] Understandably, the two-stage drive components slide using the central tube 1 and the first inner cylinder 32 as guide surfaces, respectively. Their sliding paths are independent and coaxially arranged, ensuring effective transmission of driving force and stability of structural movement. By arranging the two-stage drive components in series and providing driving force from independent hydraulic chambers, effective superposition of driving force is achieved without increasing the overall outer diameter, improving the reliability of the setting seal. At the same time, the structure is compact and adaptable to the working environment with limited downhole space.

[0037] Based on this, in one embodiment of this application, radial protrusions are provided on the outer peripheral surfaces of both the first inner cylinder 32 and the second inner cylinder 33. The first driving member 31a, the central tube 1, and the protrusions of the first inner cylinder 32 together form a first hydraulic cavity; the second driving member 31b, the protrusions of the first inner cylinder 32, and the second inner cylinder 33 together form a second hydraulic cavity. A first liquid channel connecting the flow channel and the first hydraulic cavity is provided on the central tube 1, and a second liquid channel connecting the flow channel and the second hydraulic cavity is provided on the first inner cylinder 32.

[0038] The outer circumferential surfaces of the first inner cylinder 32 and the second inner cylinder 33 are respectively provided with radial protrusions. These protrusions extend circumferentially and, together with the inner wall surface of the corresponding driving component and the end face of the adjacent cylinder, form a closed hydraulic cavity. (Refer to...) Figure 5 and Figure 6As shown, the first hydraulic chamber is formed by the inner wall surface of the first driving member 31a, the outer peripheral surface of the central tube 1, and the protrusion of the first inner cylinder 32; the second hydraulic chamber is formed by the inner wall surface of the second driving member 31b, the outer peripheral surface of the first inner cylinder 32, and the protrusion of the second inner cylinder 33. Each hydraulic chamber is independent of the others, and the sealing performance is ensured by seals disposed between the mating surfaces. The seals can adopt a combination of O-rings and O-ring back rings to meet the long-term sealing requirements under high temperature and high pressure conditions in downhole operations.

[0039] The central tube 1 has a first liquid channel connecting the flow channel and the first hydraulic chamber, and the first inner cylinder 32 has a second liquid channel connecting the flow channel and the second hydraulic chamber. When the ground pump is pressurized, the hydraulic fluid enters the first and second hydraulic chambers simultaneously through the flow channels, the first liquid channel, and the second liquid channel, respectively, and acts on the first drive component 31a and the second drive component 31b. The two driving forces are superimposed axially to push the rubber cylinder 2 to compress.

[0040] It should be noted that the first liquid channel and the second liquid channel can be radial through holes opened on the pipe wall, or they can be bent channels that extend a certain distance along the axis and then turn radially. Their specific forms can be flexibly selected according to the processing technology and flow requirements. By setting the hydraulic channels on the central pipe 1 and the first inner cylinder 32, independent liquid supply and synchronous drive of the two-stage hydraulic chambers are realized. The chambers do not interfere with each other, ensuring the uniformity and stability of the driving force output during the setting process.

[0041] In one embodiment of this application, the seat drive assembly 3 further includes a lower connector 34, a locking member 35, and a first shear pin 36. The lower connector 34 is connected to the end of the second inner cylinder 33 away from the first inner cylinder 32. The locking member 35 is fixedly connected to the second drive member 31b and is connected to the lower connector 34 through the first shear pin 36. The locking member 35 and the second inner cylinder 33 are locked in one direction.

[0042] The lower connector 34 is connected to the end of the second inner cylinder 33 furthest from the first inner cylinder 32, that is, located at the lowest end of the setting drive assembly 3. It is used to connect the working tool below the packer and to provide an initial positioning reference for the locking element 35. (Refer to...) Figure 5 and Figure 6 As shown, the locking member 35 is fixedly connected to the second driving member 31b and moves axially synchronously with the second driving member 31b. Before the setting and pressurization, the locking member 35 is connected to the lower connector 34 through the first shear pin 36 to pre-position the second driving member 31b axially, preventing the driving member from moving prematurely due to vibration or accidental disturbance during the tool's insertion process.

[0043] A one-way locking structure is provided between the locking member 35 and the second inner cylinder 33. In this embodiment, the one-way locking structure includes a first toothed surface, wherein a locking ring is provided on the inner wall of the locking member 35, and a second toothed surface is provided on the side of the locking ring near the first toothed surface. The first toothed surface and the second toothed surface only allow the locking member 35 to move in the setting direction (i.e., towards the rubber cylinder 2), and it is locked in the opposite direction. When the pressure in the hydraulic chamber rises to the design value, the first shear pin 36 breaks under shear force, and the locking member 35 moves axially towards the rubber cylinder 2 with the second driving member 31b. After moving, it is locked with the second inner cylinder 33 by the one-way locking structure, preventing the driving member from retracting due to the elastic rebound of the rubber cylinder 2 after the hydraulic pressure is removed, thereby maintaining the setting state.

[0044] It should be noted that the shear value of the first shear pin 36 can be designed to match the downhole operating conditions and the setting pressure requirements. By providing the setting initiation threshold through the first shear pin 36 and maintaining the setting position through the one-way locking structure, controllable triggering and reliable pressure holding of the setting process are achieved, ensuring that the packer maintains a stable sealing state throughout the operation.

[0045] In one embodiment of this application, the unsealing component 4 includes a connector 41 and a retainer 42. Both the connector 41 and the retainer 42 are sleeved on the outside of the central tube 1 and connected to each other, with the retainer 42 abutting against the rubber tube 2.

[0046] The unsealing component 4 consists of two parts: a connector 41 and a support 42. Both are fitted around the outer periphery of the central tube 1 and connected to each other, forming an integral unsealing support structure. (Refer to...) Figure 3 and Figure 4 As shown, the abutment 42 is located at the end of the rubber cylinder 2 away from the setting drive assembly 3, that is, above the rubber cylinder 2. It provides axial support for the rubber cylinder 2 during the axial compression setting process, prevents the rubber cylinder 2 from moving away from the setting drive assembly 3, and ensures that the setting drive force can be effectively converted into the radial expansion pressure of the rubber cylinder 2.

[0047] Connector 41 is responsible for connecting and disconnecting from the central tube 1, and support member 42 is responsible for supporting the rubber tube 2. When unsealing is required, connector 41 is lifted by a tool, the connection between connector 41 and central tube 1 is released, the axial support of support member 42 on rubber tube 2 is immediately lost, and rubber tube 2 retracts under its own elastic force, and the packer is unsealed.

[0048] In one embodiment of this application, the abutment 42 includes an upper guide ring 421, a fixing sleeve 422, and a limiting ring 423.

[0049] The upper guide ring 421 is slidably sleeved on the central tube 1. One end of the rubber sleeve 2 abuts against the upper guide ring 421, and the other end abuts against the driving component 31. (Refer to...) Figure 3 and Figure 4Specifically, the upper guide ring 421 directly contacts the upper end face of the rubber sleeve 2, providing axial support for the rubber sleeve 2 during setting and guiding the radial expansion of the upper end of the rubber sleeve 2, preventing uneven deformation of the rubber sleeve 2 during compression, and ensuring the uniformity and reliability of the sealing contact surface. It should also be noted that the upper guide ring 421 is provided with a second inner retaining ring, through which the upper guide ring 421 is connected to the rubber sleeve 2.

[0050] The fixed sleeve 422 is slidably fitted onto the central tube 1 and connected to the upper guide ring 421. A limiting portion is provided at the end of the fixed sleeve 422 away from the upper guide ring 421. This limiting portion extends circumferentially, forming an axial stop surface against the limiting ring 423. The limiting portion can be a radial flange at the end of the fixed sleeve 422 or a stepped surface at the end of the fixed sleeve 422; its specific form can be flexibly selected according to the structural space and manufacturing process.

[0051] The limiting ring 423 is slidably sleeved on the outer periphery of the fixed sleeve 422. When unsealing, the limiting ring 423 axially abuts against the limiting part on the fixed sleeve 422, which can drive the entire fixed sleeve 422 to move. Since the fixed sleeve 422 is connected to the upper guide ring 421, the fixed sleeve 422 can drive the upper guide ring 421 to move synchronously during the movement. The upper guide ring 421 then loses its axial constraint, and the supporting force of the holding member 42 on the rubber tube 2 disappears, and the rubber tube 2 completes the retraction and unsealing. Through the coordinated cooperation of the upper guide ring 421, the fixed sleeve 422 and the limiting ring 423, the holding member 42 provides stable and reliable multi-point axial support to the rubber tube 2 during the setting period, and can quickly release the constraint after the unsealing action is triggered, ensuring the timeliness and reliability of the unsealing process.

[0052] In one embodiment of this application, the connector 41 includes a connecting sleeve 411 and a release ring 412.

[0053] The connecting sleeve 411 is slidably sleeved outside the central tube 1 and connected to the limiting ring 423, forming an integral linkage relationship between the connecting member 41 and the supporting member 42. The release ring 412 is connected to the outer periphery of the central tube 1, and the connecting sleeve 411 and the release ring 412 are axially limited by the engaging structure.

[0054] It should be noted that during the setting process, the connecting sleeve 411 and the release ring 412 resist each other as follows: Figure 4 As shown, the two do not engage with each other. They only engage during the unsealing process. At this time, the connecting sleeve 411 can drive the release ring 412 and the central tube 1 to move, thereby recovering the entire packer.

[0055] It should also be noted that, referring to Figure 1 , Figure 3 and Figure 4The connecting sleeve 411 shown consists of a seated sleeve, a discarding sleeve, and an inner retaining ring. The discarding sleeve is located between the seated sleeve and the inner retaining ring and is connected to both the seated sleeve and the inner retaining ring. When it is necessary to unseal, the seated sleeve of the connecting sleeve 411 is lifted, and the discarding sleeve also moves upward. The release ring 412 engages with the connecting sleeve 411, and the central tube 1 can be lifted and retrieved.

[0056] In one embodiment of this application, the engaging structure includes: a plurality of annular grooves on the outer peripheral surface of the release ring 412, and an annular protrusion on the inner wall of the connecting sleeve 411. The release ring 412 is a ring body with an axial opening and an axially extending slot along the circumference to form an elastic arm. The elastic arm can deform radially to disengage the annular protrusion from the annular grooves.

[0057] Specifically, the outer circumferential surface of the release ring 412 is provided with multiple annular grooves along the axial direction, and the inner wall of the connecting sleeve 411 is provided with annular protrusions that cooperate with them. In the initial state, the annular protrusions do not engage with the annular grooves, and the protrusions between the connecting sleeve 411 and the release ring 412 abut against each other. (Refer to...) Figure 7 As shown, the release ring 412 is a split ring with an axial opening; that is, the release ring 412 is not a complete closed ring, but has a break extending axially. Simultaneously, the release ring 412 has an axially extending slot along its circumferential direction, dividing the release ring 412 circumferentially into several elastic arms, each of which can elastically deform in the radial direction. When released, the elastic arms expand radially outward, the annular protrusion remains engaged in the annular groove, and the connecting sleeve 411 and the release ring 412 remain axially locked.

[0058] In one embodiment of this application, the connector 41 further includes an intermediate joint 413. The intermediate joint 413 is connected to the end of the central tube 1, and the intermediate joint 413 is connected to the connecting sleeve 411 by a second shear pin 414.

[0059] Specifically, the intermediate joint 413 is connected to the upper end of the central tube 1, that is, the end of the packer located near the ground. It is used to receive the upward lifting force from above and transmit it to the central tube 1, while also serving as the axial constraint reference element for the connecting sleeve 411. (Refer to...) Figure 3 and Figure 4 As shown, the intermediate connector 413 and the connecting sleeve 411 are connected by the second shear pin 414. During the tool insertion and setting and pressurization process, the second shear pin 414 axially pre-fixes the connecting sleeve 411 to prevent the connecting sleeve 411 from axially displacing during the non-unsealing operation stage, and ensures that the holding member 42 continuously and stably provides axial support for the rubber sleeve 2.

[0060] When release is required, the connecting sleeve 411 is lifted using a GS tool. Once the lifting force reaches the design shear load of the second shear pin 414, the second shear pin 414 breaks, and the intermediate joint 413 disengages from the connecting sleeve 411. Subsequent release actions are then triggered sequentially. For example, the design shear value of the second shear pin 414 can be set to approximately 1500 LBS, which is far lower than the release force required by traditional slip-anchored packers and can be easily achieved within the bearing capacity of conventional working tubing.

[0061] It should be noted that the shear value of the second shear pin 414 can be designed and matched according to the downhole working conditions and unsealing load requirements to ensure that unsealing is triggered within the normal lifting operation range, and will not be accidentally triggered during the lowering and setting processes, thus achieving precise control of the unsealing initiation timing. By using the second shear pin 414 to control the unsealing trigger load at a threshold, the unsealing process has clear mechanical initiation conditions. This, combined with the low-force unlocking of the subsequent locking structure, achieves the controllability and low release force characteristics of the entire unsealing process.

[0062] Reference Figure 3 and Figure 4 As shown, during the unsealing process, the sleeve of the connecting sleeve 411 abuts against the lower end of the intermediate connector 413, forming an axial limiting fit, thereby restricting the upward movement of the connecting sleeve 411. This limiting structure prevents excessive displacement of the connecting sleeve 411 during the lifting process, avoids unexpected interference or disengagement between related components, ensures that the unsealing action is completed in a predetermined sequence, and improves the controllability and reliability of the unsealing process.

[0063] In one embodiment of this application, the system further includes an elastic claw 5, an upper connector 6, and a piston 7. The elastic claw 5 is located inside the connecting sleeve 411 and engages with the intermediate connector 413. The upper connector 6 is connected to the inner side of the elastic claw 5, and the piston 7 is connected to the elastic claw 5 via a third shear pin 8.

[0064] Specifically, the elastic claw 5 is located radially inside the connecting sleeve 411, and a releasable connection is achieved with the intermediate connector 413 via a snap-fit ​​structure. (Refer to...) Figure 1 and Figure 2 As shown, for example, the elastic claw 5 can adopt a structure of multiple elastic claw flaps distributed circumferentially. Each claw flap has a snap-fit ​​protrusion on its inner side, which engages with the annular groove on the inner circumferential surface of the intermediate connector 413. The elastic claw 5 has a certain elastic deformation capacity in the radial direction, and maintains the engagement with the intermediate connector 413 under normal axial force, thereby achieving a reliable connection between the two.

[0065] The upper connector 6 is connected to the inner side of the elastic claw 5, that is, the upper connector 6 is located in the radial inner space of the elastic claw 5. It is used to connect the working tool above the packer and transmit the lifting force to the intermediate connector 413 and the central tube 1 through the elastic claw 5.

[0066] The piston 7 is sleeved on the outer periphery of the elastic claw 5 or at an adjacent position, and is fixedly connected to the elastic claw 5 by the third shear pin 8. In the set state, the piston 7 remains axially fixed, constraining the radial displacement of the elastic claw 5, and preventing the elastic claw 5 from radially contracting and disengaging from the intermediate joint 413 during the non-release operation phase.

[0067] Understandably, when a release operation is required, a ball is thrown into the flow channel and hydraulic pressure is applied. The hydraulic pressure acts on the force-bearing surface of piston 7. When the pressure reaches the design shear value of the third shear pin 8, the third shear pin 8 breaks, and piston 7 moves axially under the action of hydraulic pressure, no longer restricting the radial displacement of elastic claw 5. At this time, the lifting tool is engaged for the lifting operation. Under the action of the lifting force, each claw of elastic claw 5 undergoes radial contraction, and the locking protrusion disengages from the annular groove on the outer circumference of the intermediate joint 413, completing the separation of the upper tool from the packer body, i.e., the release operation. After the release is completed, the packer remains downhole to continue to maintain the set state, and the upper tubing string can be freely lifted, creating conditions for subsequent stratified construction operations.

[0068] It should be noted that the release operation and the unsealing operation are completely separated in function through the coordinated cooperation of the elastic claw 5 and the piston 7. The two are controlled by independent shear pins (the third shear pin 8 and the second shear pin 414) and do not interfere with each other. In other words, the unsealing action will not be triggered when the release operation is performed, and the state of the release mechanism will not be affected when the unsealing operation is performed, thus ensuring the flexibility and safety of the downhole operation process.

[0069] It should be noted that, for example Figure 2 As shown, an outward protruding step is provided on the outer periphery of the piston 7, and an inner step groove is provided on the inner side of the elastic claw 5. When the third shearing pin 8 is sheared, the piston 7 moves downward. The downward position of the piston 7 can be limited by the mutual abutment of the outward protruding step and the inner step groove. At the same time, during the release process, the piston 7 can also be moved upward by the elastic claw 5. [1] To facilitate understanding of the complete working process of the packer in this application, the setting process, release process, and unsealing process are described in series below.

[0070] Sealing process After the packer is lowered to the predetermined well depth with the working tubing, a ball is dropped into the packer, and hydraulic fluid is pumped from the surface into the flow channel of the central tube 1 through the tubing. The hydraulic fluid flows through the flow channel, passing through the first liquid channel on the central tube 1 and the second liquid channel on the first inner cylinder 32, and simultaneously enters the first hydraulic chamber and the second hydraulic chamber. As the pumping pressure gradually increases, the hydraulic pressure in the two hydraulic chambers simultaneously acts on the first drive component 31a and the second drive component 31b. When the hydraulic pressure reaches the design shear value of the first shear pin 36, the first shear pin 36 breaks, and the second drive component 31b moves axially towards the rubber sleeve 2 under the drive of the hydraulic force in the second hydraulic chamber, while the first drive component 31a simultaneously advances axially along the central tube 1 under the action of the hydraulic pressure in the first hydraulic chamber. The two driving forces are superimposed axially and act together on the lower end of the rubber sleeve 2, applying an axial compressive force to the rubber sleeve 2.

[0071] During this process, the upper end of the rubber sleeve 2 is provided with stable axial support by the abutment member 42 in the unsealing assembly 4, specifically the upper guide ring 421. Under the axial constraint at both ends, the rubber sleeve 2 expands radially, forming a tight interference seal with the inner wall of the sleeve, completing the interlayer sealing. After the setting is completed, the locking member 35 moves with the second driving member 31b and locks with the second inner cylinder 33 through a one-way locking structure, preventing the driving member from reversing due to the elastic rebound of the rubber sleeve 2 after the hydraulic pressure is removed, thereby maintaining a stable setting state. After this, the pump pressure is stopped at ground level, and the setting process ends.

[0072] Dropping process After setting, if it is necessary to separate the upper tubing from the packer body, a release operation is performed. A plugging ball is dropped into the flow channel from the ground, allowing it to sit in the ball seat position of piston 7. Hydraulic pressure is then applied to the tubing. The hydraulic pressure acts on the force-bearing surface of piston 7. When the pressure rises to the design shear value of the third shear pin 8, the third shear pin 8 breaks, and piston 7 moves axially under hydraulic pressure, no longer constraining the radial displacement of the claw segments of the elastic claw 5.

[0073] Subsequently, a lifting force is applied from the ground using the GS tool, which is transmitted to the elastic claw 5 via the upper connector 6. Under the action of the lifting force, each claw petal of the elastic claw 5 undergoes radial contraction deformation, and the snap-fit ​​protrusion disengages from the annular groove on the inner circumferential surface of the intermediate connector 413. The snap-fit ​​relationship between the elastic claw 5 and the intermediate connector 413 is released, and the upper tubing string is completely separated from the packer body. After the release is completed, the packer remains in the downhole to maintain a set seal, and the upper tubing string is freely lifted, creating conditions for subsequent layered construction operations. It should be noted that the release operation and the unsealing operation are controlled separately by their independent shear pins (the third shear pin 8 and the second shear pin 414), without interference. The release operation will not trigger the unsealing action, ensuring the safety and flexibility of the downhole operation process.

[0074] Unlocking process When the packer needs to be retrieved after the stratification operation is completed, the unsealing operation is performed. The ground connects to the connecting sleeve 411 via a GS tool, and an axial upward force is applied to the connecting sleeve 411. When the upward force gradually increases to the design shear value of the second shear pin 414 (approximately 1500 LBS), the second shear pin 414 breaks, and the fixing relationship between the connecting sleeve 411 and the intermediate joint 413 is released.

[0075] Under the action of the lifting force, the connecting sleeve 411 moves upward axially. At this time, the annular protrusion on the inner wall of the connecting sleeve 411 engages with the annular groove on the outer circumferential surface of the release ring 412, and the connecting sleeve 411 drives the release ring 412 to move upward synchronously. Since the release ring 412 has an axial opening and circumferentially distributed slots, the elastic arm expands outward radially during the lifting process, maintaining the engagement state between the annular protrusion and the annular groove, ensuring the reliability of the linkage between the connecting sleeve 411 and the release ring 412. As the connecting sleeve 411 continues to move upward, the limiting ring 423 and the limiting part on the fixed sleeve 422 form axial resistance, driving the fixed sleeve 422 and the upper guide ring 421 connected to it to move upward synchronously. The axial support of the upper guide ring 421 on the rubber sleeve 2 then fails, and the rubber sleeve 2 retracts radially under the action of its own elastic force, disengaging from the sealing contact with the inner wall of the sleeve, and the interlayer seal is released.

[0076] Simultaneously, the release sleeve of the connecting sleeve 411 and the lower end of the intermediate joint 413 form an axial abutment limit, preventing the connecting sleeve 411 from moving excessively upward and ensuring that each component operates in an orderly manner according to a predetermined sequence. Continuing to lift the connecting sleeve 411, the connecting sleeve 411 and the release ring 412 drive the central tube 1 and the entire packer body upward and retrieved along with the tubing string, completing the packer's release and safe exit from the well. Throughout the entire release process, the release component 4 does not bear any hydraulic pressure from the hydraulic chamber. The lifting force required for release is only the initial design shear value of the second shear pin 414, approximately 1500 LBS, far lower than the tens of tons of release force required by traditional slip-anchored packers. This characteristic fundamentally solves the technical contradiction in traditional solutions where higher setting pressure leads to greater release difficulty, significantly improving the success rate of release and operational safety.

[0077] 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.

[0078] 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 packer, characterized by, include: A central tube (1) is provided with a flow channel for fluid to pass through; A rubber sleeve (2) is fitted over the central tube (1); The setting drive assembly (3) is sleeved outside the central tube (1) and abuts against the rubber cylinder (2). The setting drive assembly (3) includes at least two drive members (31) arranged in series along the axial direction. Each drive member (31) has a hydraulic cavity that communicates with the flow channel between it and the central tube (1). Each drive member (31) is used to move axially when fluid is introduced into the hydraulic cavity and to compress the rubber cylinder (2). The unsealing component (4) is sleeved outside the central tube (1) and abuts against the rubber cylinder (2). The unsealing component (4) is isolated from each of the hydraulic chambers so that the unsealing component (4) does not bear the hydraulic pressure in the hydraulic chamber during the setting and pressurizing process. The unsealing component (4) is used to release the axial support of the rubber cylinder (2) when it is lifted axially, so that the rubber cylinder (2) retracts and the central tube (1) is lifted and retracted.

2. The packer of claim 1, wherein, The seat seal drive assembly (3) further includes a first inner cylinder (32) and a second inner cylinder (33). The first inner cylinder (32) is sleeved and fixed outside the central tube (1), and the second inner cylinder (33) is coaxially connected to the end of the first inner cylinder (32) away from the rubber tube (2). At least two of the driving components (31) include a first driving component (31a) and a second driving component (31b). The first driving component (31a) is slidably sleeved on the central tube (1), and the second driving component (31b) is slidably sleeved on the first inner cylinder (32). The first driving component (31a) and the second driving component (31b) are axially connected in series.

3. The packer of claim 2, wherein, Both the first inner cylinder (32) and the second inner cylinder (33) have radial protrusions on their outer peripheral surfaces; The protrusions of the first driving member (31a), the central tube (1) and the first inner cylinder (32) together form a first hydraulic cavity, and the protrusions of the second driving member (31b), the first inner cylinder (32) and the second inner cylinder (33) together form a second hydraulic cavity. The central tube (1) has a first liquid channel that connects the flow channel and the first hydraulic chamber, and the first inner cylinder (32) has a second liquid channel that connects the flow channel and the second hydraulic chamber.

4. The packer of claim 2, wherein, The seat drive assembly (3) further includes a lower connector (34), a locking member (35), and a first shear pin (36). The lower connector (34) is connected to the end of the second inner cylinder (33) away from the first inner cylinder (32). The locking member (35) is fixedly connected to the second drive member (31b) and is connected to the lower connector (34) through the first shear pin (36). The locking member (35) is unidirectionally locked to the second inner cylinder (33).

5. The packer of claim 1, wherein, The deblocking assembly (4) comprises a connecting piece (41) and an abutting piece (42), the connecting piece (41) and the abutting piece (42) are sleeved outside the central pipe (1) and connected, and the abutting piece (42) abuts against the rubber cylinder (2).

6. The packer of claim 5, wherein, The abutting piece (42) comprises: an upper guide ring (421) which is slidably sleeved on the central pipe (1), one end of the rubber cylinder (2) abuts against the upper guide ring (421), and the other end abuts against the driving piece (31); a fixing sleeve (422) which is slidably sleeved on the central pipe (1) and connected with the upper guide ring (421), and one end of the fixing sleeve (422) away from the upper guide ring (421) is provided with a limiting part; a limiting ring (423) which is slidably sleeved on the outer periphery of the fixing sleeve (422), and the limiting ring (423) can axially abut against the limiting part.

7. The packer of claim 6, wherein, The connecting piece (41) comprises: a connecting sleeve (411) which is slidably sleeved outside the central pipe (1) and connected with the limiting ring (423); a release ring (412) which is connected to the outer periphery of the central pipe (1), and the connecting sleeve (411) and the release ring (412) are axially limited by a clamping structure.

8. The packer of claim 7, wherein, The clamping structure comprises: a plurality of annular grooves provided on the outer peripheral surface of the release ring (412), and an annular protrusion provided on the inner wall of the connecting sleeve (411); the release ring (412) is an annular body provided with an axial opening, and an axially extending slot is formed on the circumferential direction to form a resilient arm, the resilient arm can be radially deformed, so that the annular protrusion is separated from the annular groove.

9. The packer of claim 7, wherein, The connecting piece (41) further comprises an intermediate joint (413), the intermediate joint (413) is connected to the end of the central pipe (1), and the intermediate joint (413) is connected with the connecting sleeve (411) through a second shear pin (414).

10. The packer of claim 9, wherein, Further comprising an elastic claw (5), an upper joint (6) and a piston (7), the elastic claw (5) is located on the inner side of the connecting sleeve (411) and is clamped with the intermediate joint (413), the upper joint (6) is connected to the inner side of the elastic claw (5), and the piston (7) is connected with the elastic claw (5) through a third shear pin (8).

Images