An auxiliary pressure-bearing and unsealing mechanism and an expansion packer

Abstract

This invention relates to the field of oil and gas extraction equipment technology, and particularly to an auxiliary pressure-bearing and unsealing mechanism and an expanding packer, aiming to solve the problems of unsealing difficulties and packer failure caused by deformation of the expanding rubber sleeve. The auxiliary pressure-bearing and unsealing mechanism of this invention includes a soluble limiting compensation sleeve, an elastic expanding main shoulder protector, and an elastic expanding supplementary shoulder protector. The soluble limiting compensation sleeve is inserted into the elastic expanding main shoulder protector, the elastic expanding supplementary shoulder protector is fitted into the elastic expanding main shoulder protector, and the soluble limiting compensation sleeve is fitted into the expanding rubber sleeve. The soluble limiting compensation sleeve is configured to expand with the expanding rubber sleeve and dissolve after expansion. After the elastic expanding main shoulder protector and the elastic expanding supplementary shoulder protector expand with the expanding rubber sleeve, their end faces abut against the shoulder of the expanding rubber sleeve, assisting the expanding rubber sleeve to retract under its own elastic force during unsealing. Simultaneously, the soluble limiting compensation sleeve gradually dissolves after setting, leaving space for the elastic expanding main shoulder protector and the expanding rubber sleeve to retract and ensure unsealing.

Description

Technical Field

[0001] This invention relates to the field of oil and gas extraction equipment technology, and in particular to an auxiliary pressure-bearing and unsealing mechanism and an expansion packer. Background Technology

[0002] In oil and gas field development, expanded packers are crucial tools for isolating pressure, enabling segmented development and phased operational procedures in oil and gas wells. However, after prolonged downhole use, expanded packers often experience permanent outward deformation of the expansion sleeve, preventing complete retraction. This can lead to pipe string jamming and other operational risks during packer removal. Furthermore, during pressurization, the shoulder of the expansion sleeve bears concentrated pressure loads, causing localized compression and deformation. In severe cases, cracks can form at the deformation points, leading to leakage and packer failure. Summary of the Invention

[0003] The purpose of this invention is to provide an auxiliary pressure-bearing and unsealing mechanism and an expansion packer to solve the problems of unsealing difficulties and loss of seal caused by the deformation of the expansion packer.

[0004] To solve the above-mentioned technical problems, the technical solution provided by the present invention is as follows:

[0005] An auxiliary pressure-bearing and unsealing mechanism includes a soluble limiting compensation sleeve, an elastic expansion main shoulder protector, and an elastic expansion supplementary shoulder protector. The soluble limiting compensation sleeve is inserted into the elastic expansion main shoulder protector, the elastic expansion supplementary shoulder protector is fitted into the elastic expansion main shoulder protector, and the soluble limiting compensation sleeve is fitted into the expansion tube. The soluble limiting compensation sleeve is configured to expand with the expansion tube and dissolve after expansion. After the elastic expansion main shoulder protector and the elastic expansion supplementary shoulder protector expand with the expansion tube, their end faces abut against the shoulder of the expansion tube, and assist the expansion tube in retracting under its own elastic force during unsealing.

[0006] Furthermore, the auxiliary pressure-bearing and unsealing mechanism also includes a shoulder protection cap, which is fitted onto the elastic expansion main shoulder and the elastic expansion supplementary shoulder; the side of the elastic expansion main shoulder and the elastic expansion supplementary shoulder that is close to the shoulder of the expansion tube is the expansion end, and there is an expansion space between the expansion end of the elastic expansion supplementary shoulder and the shoulder protection cap.

[0007] Furthermore, the expansion end of the elastic expansion main shoulder is evenly distributed with multiple first slits along the circumference to form an elastic cantilever beam; the expansion end of the elastic expansion supplementary shoulder is evenly distributed with multiple second slits along the circumference to form an elastic cantilever beam; the first slits and the second slits are arranged alternately.

[0008] Furthermore, the sidewall of the soluble limiting compensation sleeve is provided with a through cut.

[0009] Furthermore, the material of the soluble limiting compensation sleeve is magnesium-aluminum alloy.

[0010] Furthermore, the outer side of the soluble limiting compensation sleeve is provided with a soluble surface, which is covered by the elastically expanding main shoulder.

[0011] Furthermore, the soluble limiting compensation sleeve is matched with the elastic expansion main shoulder to ensure interference fit.

[0012] Furthermore, the expansion end of the elastic expansion main shoulder is provided with a first flange, which abuts against the shoulder of the expansion tube.

[0013] Furthermore, the expansion end of the elastic expansion supplement shoulder is provided with a second flange, which abuts against the first flange.

[0014] In another aspect of the present invention, an expansion packer includes an auxiliary pressure-bearing and unsealing mechanism as described above.

[0015] In summary, the technical effects achieved by this invention are as follows:

[0016] This invention provides an auxiliary pressure-bearing and unsealing mechanism comprising a soluble limiting compensation sleeve, an elastic expansion main shoulder protector, and an elastic expansion supplementary shoulder protector. The soluble limiting compensation sleeve is inserted into the elastic expansion main shoulder protector, the elastic expansion supplementary shoulder protector is fitted into the elastic expansion main shoulder protector, and the soluble limiting compensation sleeve is fitted into the expansion tube. The soluble limiting compensation sleeve is configured to expand with the expansion tube and dissolve after expansion. After the elastic expansion main shoulder protector and the elastic expansion supplementary shoulder protector expand with the expansion tube, their end faces abut against the shoulder of the expansion tube, and assist the expansion tube in retracting under its own elastic force during unsealing.

[0017] Because the elastic expansion main shoulder and elastic expansion supplementary shoulder of the auxiliary pressure-bearing and unsealing mechanism provided by this invention expand outward along with the expansion tube during setting and abut against the shoulder of the expansion tube, the shoulder of the expansion tube is supported by the elastic expansion main shoulder and elastic expansion supplementary shoulder when subjected to the pressure difference above and below the annulus. This prevents excessive deformation of the expansion tube and effectively avoids leakage due to cracks in the expansion tube, thus preventing loss of seal. During unsealing, the elastic expansion main shoulder and elastic expansion supplementary shoulder return to their original shape under their own elasticity, assisting in compressing the expansion tube to contract. At the same time, the dissolvable limiting compensation sleeve gradually dissolves after setting, leaving sufficient space between the elastic expansion main shoulder and the expansion tube to ensure that the elastic expansion main shoulder and elastic expansion supplementary shoulder retract under their own elasticity. At this time, even if the shoulder of the expansion tube is severely deformed due to prolonged pressure, the packer as a whole can still be unsealed. Attached Figure Description

[0018] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the structure of the expanded packer provided in an embodiment of the present invention;

[0020] Figure 2 This is a schematic diagram of the auxiliary pressure-bearing and unsealing mechanism provided in an embodiment of the present invention;

[0021] Figure 3 A schematic diagram of the assembly of the elastic expansion main shoulder guard and the elastic expansion supplementary shoulder guard;

[0022] Figure 4 for Figure 3 Cross-sectional view of the middle section (BB);

[0023] Figure 5 for Figure 3 Cross-sectional view of the BB section after expansion of the elastically expanded main shoulder and the elastically expanded supplementary shoulder;

[0024] Figure 6 Top view of the soluble limiting compensation sleeve;

[0025] Figure 7 This is a cross-sectional view of the soluble limiting compensation sleeve.

[0026] Icons: 100-Dissolvable limiting compensation sleeve; 200-Elastic expansion main shoulder protector; 300-Elastic expansion supplementary shoulder protector; 400-Shoulder protector outer cap; 110-Through cut; 120-Dissolvable surface; 210-First slit; 220-First flange; 310-Second slit; 320-Second flange; a-Expansion space; 1-Joint; 2-Center tube; 3-Expansion sleeve; 4-Limiting ring; 5-Auxiliary pressure bearing and unsealing mechanism. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0028] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0029] The following detailed description of some embodiments of the present invention is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0030] Example 1:

[0031] During the pressurization process, the shoulder of the expansion packer will bear concentrated pressure load, causing local compression and deformation of the shoulder of the expansion packer. In more severe cases, cracks will appear at the deformation point, causing leakage and resulting in the packer losing its seal.

[0032] In view of this, the present invention provides an auxiliary pressure-bearing and unsealing mechanism comprising a soluble limiting compensation sleeve 100, an elastic expansion main shoulder protector 200, and an elastic expansion supplementary shoulder protector 300; the soluble limiting compensation sleeve 100 is inserted into the elastic expansion main shoulder protector 200, the elastic expansion supplementary shoulder protector 300 is fitted onto the elastic expansion main shoulder protector 200, and the soluble limiting compensation sleeve 100 is fitted onto the expansion tube 3. The soluble limiting compensation sleeve 100 is configured to expand with the expansion tube 3 and dissolve after expansion; after the elastic expansion main shoulder protector 200 and the elastic expansion supplementary shoulder protector 300 expand with the expansion tube 3, their end faces abut against the shoulder of the expansion tube, and assist the expansion tube 3 in retracting under its own elastic force during unsealing.

[0033] Because the elastic expansion main shoulder 200 and elastic expansion supplementary shoulder 300 of the auxiliary pressure-bearing and unsealing mechanism provided by this invention expand outward along with the expansion cylinder 3 during setting and abut against the shoulder of the expansion cylinder 3, the shoulder of the expansion cylinder 3 is supported by the elastic expansion main shoulder 200 and elastic expansion supplementary shoulder 300 when it is subjected to the pressure difference above and below the annulus, preventing excessive deformation of the expansion cylinder 3 and effectively avoiding leakage due to cracks in the expansion cylinder 3, thus preventing loss of seal. During unsealing, the elastic expansion main shoulder 200 and elastic expansion supplementary shoulder 300 return to their original shape under their own elastic force, assisting in compressing the expansion cylinder 3 to contract. Meanwhile, the dissolvable limiting compensation sleeve 100 gradually dissolves after setting, leaving enough space between the elastic expansion main shoulder protector 200 and the expansion sleeve 3 to ensure that the elastic expansion main shoulder protector 200 and the elastic expansion supplementary shoulder protector 300 retract under their own elastic force. At this time, even if the expansion sleeve 3 is severely deformed due to long-term pressure, the packer as a whole can still be unsealed.

[0034] The following combination Figures 1-7The structure and shape of the auxiliary pressure-bearing and unsealing mechanism provided in this embodiment are described in detail below:

[0035] In an optional embodiment, the auxiliary pressure-bearing and unsealing mechanism 5 further includes a shoulder protection cap 400. For example... Figure 2 As shown, the outer cap 400 of the shoulder protector is fitted onto the elastic expansion main shoulder protector 200 and the elastic expansion supplementary shoulder protector 300. The expansion end of the elastic expansion main shoulder protector 200 and the elastic expansion supplementary shoulder protector 300 is located on the side closest to the shoulder of the expansion sleeve 3. There is an expansion space 'a' between the expansion end of the elastic expansion supplementary shoulder protector 300 and the outer cap 400. The outer cap 400 restricts the expansion range of the elastic expansion main shoulder protector 200 and the elastic expansion supplementary shoulder protector 300, preventing them from excessively deforming and becoming unable to retract. Simultaneously, under the restriction of the outer cap 400, the elastic expansion main shoulder protector 200, and the elastic expansion supplementary shoulder protector 300, the expansion sleeve 3 will not undergo further compression deformation or glue leakage, effectively avoiding tearing and leakage of the expansion sleeve 3, improving sealing performance and achieving auxiliary pressure resistance.

[0036] Specifically, the upper side of the elastic expansion main shoulder protector 200 is provided with an external thread, and the upper side of the shoulder protector outer cap 400 is provided with an internal thread. The elastic expansion main shoulder protector 200 and the shoulder protector outer cap 400 are connected by threads.

[0037] In this embodiment, as Figure 3 As shown, the expansion end of the elastic expansion main shoulder protector 200 is provided with a first flange 220, which abuts against the shoulder of the expansion sleeve 3. The expansion end of the elastic expansion supplementary shoulder protector 300 is provided with a second flange 320, which abuts against the first flange 220. By limiting the first flange 220, the elastic expansion main shoulder protector 200 and the shoulder protector outer cap 400 limit the elastic expansion supplementary shoulder protector 300, so that the elastic expansion supplementary shoulder protector 300 is locked in the annular space of the elastic expansion main shoulder protector 200 and the shoulder protector outer cap 400.

[0038] Specifically, during the expansion of the expansion sleeve 3, the first flange 220 and the second flange 320 expand accordingly, increasing their diameter and abutting against the inner wall of the sleeve, assisting the expansion sleeve 3 in sealing. Simultaneously, because the first flange 220 increases the area of ​​the elastic expansion main shoulder 200 abutting against the shoulder of the expansion sleeve 3, it effectively improves the stress on the shoulder of the expansion sleeve 3, preventing excessive deformation of the expansion sleeve 3 and thus sealing failure when it is subjected to annular pressure differential.

[0039] Furthermore, the lower end face of the second flange 320 abuts against the first flange 220, while the upper end face of the second flange 320 abuts against the lower end of the shoulder protection cap 400, so that the first flange 220 is reliably supported by the shoulder protection cap 400, preventing the expansion sleeve 3 from deforming too much and causing the first flange 220 to deform. This effectively improves the support capacity of the elastic expansion main shoulder protection 200 and the elastic expansion supplementary shoulder protection 300 for the expansion sleeve 3, ensuring the reliability of the seal.

[0040] In an optional embodiment, the soluble limiting compensation sleeve 100 is made of magnesium-aluminum alloy, which is soluble in a saltwater environment. The soluble limiting compensation sleeve 100 is subjected to anodizing treatment to form a passivation layer that prevents dissolution.

[0041] Furthermore, the outer side of the soluble limiting compensation sleeve 100 is provided with a soluble surface 120, which is covered by the elastically expandable main shoulder protector 200, such as... Figure 2 , Figure 7 As shown. Specifically, the passivation layer on the outer surface of the anodized soluble limiting compensation sleeve 100 is removed to obtain the soluble surface 120. Furthermore, the passivation layer is retained at the flange of the soluble limiting compensation sleeve 100, and only the passivation layer of the portion of the soluble limiting compensation sleeve 100 inserted into the elastic expansion main shoulder 200 is removed to avoid direct contact between the flange and the brine, which would cause the soluble limiting compensation sleeve 100 to dissolve prematurely.

[0042] In this embodiment, the soluble limiting compensation sleeve 100 and the elastic expansion main shoulder protector 200 are interference-fitted to fix the soluble limiting compensation sleeve 100 and prevent it from loosening. At the same time, the interference fit allows the elastic expansion main shoulder protector 200 to protect the soluble surface 120 and prevent salt water from entering between the soluble surface 120 and the elastic expansion main shoulder protector 200.

[0043] Furthermore, the side wall of the soluble limiting compensation sleeve 100 is provided with a through cut 110, such as... Figure 6 As shown, this ensures that the soluble limiting compensation sleeve 100 can expand together with the expanding tube 3. Specifically, the through cut 110 is a slanted cut, or it can be a cut along the radial direction of the soluble limiting compensation sleeve 100, as long as the diameter of the soluble limiting compensation sleeve 100 can be increased.

[0044] In this embodiment, the expansion end of the elastic expansion main shoulder protector 200 has multiple first slits 210 evenly distributed along the circumference, forming an elastic cantilever beam; the expansion end of the elastic expansion supplementary shoulder protector 300 has multiple second slits 310 evenly distributed along the circumference, forming an elastic cantilever beam; thereby improving the expansion effect of the elastic expansion main shoulder protector 200 and the elastic expansion supplementary shoulder protector 300, such as Figure 3 , Figure 4As shown. Furthermore, the first slit 210 and the second slit 310 are staggered to prevent a connecting seam between them, thus avoiding premature dissolution of the soluble limiting compensation sleeve 100 and preventing its failure. When the expanding tube 3 expands, the first slit 210 and the second slit 310 increase simultaneously, but remain staggered, preventing a connecting seam. At this time, the brine can gradually contact the soluble surface 120 through the second slit 310, the gap between the elastic expanding main shoulder protector 200 and the elastic expanding supplementary shoulder protector 300, and the first slit 210. Specifically, the soluble limiting compensation sleeve 100 dissolves after the expanding tube 3 expands, ensuring sufficient retraction space between the expanding tube 3 and the elastic expanding main shoulder protector 200 when permanent deformation occurs, ensuring the packer can be released. If the soluble limiting compensation sleeve 100 dissolves prematurely, the expanding tube 3 will come into complete contact with the elastic expanding main shoulder protector 200 during expansion. After the expanding tube 3 undergoes permanent deformation, the elastic expanding main shoulder protector 200 will be blocked by the expanding tube 3 and will not be able to retract to assist the expanding tube 3 in unsealing, resulting in the inability to unseal smoothly.

[0045] The working process of the auxiliary pressure-bearing and unsealing mechanism provided in this embodiment is as follows:

[0046] The expanding rubber sleeve 3 expands under hydraulic pressure upon liquid inlet, causing the soluble limiting compensation sleeve 100, the elastic expanding main shoulder protector 200, and the elastic expanding supplementary shoulder protector 300 to expand outwards together until the first flange 220 and the second flange 320 abut against the inner wall of the sleeve and complete the seal. Simultaneously, the first flange 220 abuts against the shoulder of the expanding rubber sleeve 3 to prevent excessive deformation. At this time, the first slit 210 and the second slit 310 expand, and the brine gradually dissolves the soluble limiting compensation sleeve 100 after passing through the first slit 210 and the second slit 310, creating a retraction space between the expanding rubber sleeve 3 and the elastic expanding main shoulder protector 200. Through the mechanical support of the auxiliary pressure-bearing and unsealing mechanism 5, excessive compression deformation or rubber leakage of the expanding rubber sleeve 3 is prevented, especially improving the pressure deformation of the shoulder of the expanding rubber sleeve 3, effectively avoiding tearing and leakage, and improving the sealing performance and pressure-bearing capacity of the expanding rubber sleeve 3.

[0047] During unsealing, the elastic expansion main shoulder protector 200 and the elastic expansion supplementary shoulder protector 300 retract under their own elastic force, thereby assisting the retraction of the expansion sleeve 3, improving the retraction of the shoulder with the largest deformation of the expansion sleeve 3, assisting the overall retraction of the expansion sleeve 3, and reducing the impact of the shoulder deformation of the expansion sleeve 3 on the retraction of the expansion sleeve 3. At the same time, due to the existence of the retraction space between the expansion sleeve 3 formed after the dissolvable limiting compensation sleeve 100 dissolves and the elastic expansion main shoulder protector 200, even if the shoulder of the expansion sleeve 3 is severely deformed and cannot retract under its own elastic force to achieve unsealing, the retraction function of the elastic expansion main shoulder protector 200 and the elastic expansion supplementary shoulder protector 300 can still be guaranteed. After the elastic expansion main shoulder protector 200 and the elastic expansion supplementary shoulder protector 300 retract, unsealing can be achieved through the movable tubing, ultimately achieving the effect of unsealing even if the expansion sleeve 3 is severely deformed due to long-term pressure.

[0048] The soluble limiting compensation sleeve 100 limits the deformation of the shoulder of the expanding tube 3 during expansion, preventing excessive deformation. After expansion, the soluble limiting compensation sleeve 100 dissolves, leaving space for the elastic expansion main shoulder protector 200 and the elastic expansion supplementary shoulder protector 300 to retract during the retraction of the expanding tube 3. This ensures the retraction of the elastic expansion main shoulder protector 200 and the elastic expansion supplementary shoulder protector 300 themselves, as well as their assistance to the retraction of the expanding tube 3. If the soluble limiting compensation sleeve 100 is not used, although the elastic expansion main shoulder protector 200 can limit the deformation of the shoulder of the expanding tube, if the shoulder of the expanding tube 3 undergoes permanent deformation due to prolonged pressure, the expanding tube 3 will block the elastic expansion main shoulder protector 200 and the elastic expansion supplementary shoulder protector 300. Consequently, the first flange 220 and the second flange 320 will block the inner wall of the sleeve, preventing the tubing from moving and affecting unsealing.

[0049] Example 2:

[0050] An expandable packer includes an auxiliary pressure-bearing and unsealing mechanism 5 as described in Embodiment 1, and further includes a connector 1, a central tube 2, a limiting ring 4, and an expandable tube 3. Specifically, the auxiliary pressure-bearing and unsealing mechanism 5 is fitted onto the central tube 2, and the expandable tube 3 is fitted onto the central tube 2. The expandable tube 3 has auxiliary pressure-bearing and unsealing mechanisms 5 at both its upper and lower ends. The expandable tube 3 is thicker in the middle and thinner at both ends, and the transition between the two ends and the middle of the expandable tube 3 is the shoulder of the expandable tube 3.

[0051] Furthermore, the side wall of the central tube 2 has a connecting hole that connects to the expansion tube 3. When the expansion tube 3 expands, high-pressure liquid is injected into the central tube 2. The high-pressure liquid enters the interior of the expansion tube 3 through the connecting hole, causing the expansion tube 3 to expand under hydraulic action.

[0052] The lower side of the connector 1 is fitted onto the upper side of the central tube 2 and limits the auxiliary pressure bearing and unsealing mechanism 5; the limiting ring 4 is fitted onto the lower side of the central tube 2 and cooperates with the connector 1 to fix the expansion tube 3 and the auxiliary pressure bearing and unsealing mechanism 5 at both ends of the expansion tube 3.

[0053] In this embodiment, a sealing ring is provided between the auxiliary pressure-bearing and unsealing mechanism 5 and the central tube 2, and a sealing ring is provided between the lower side of the connector 1 and the central tube 2 to improve the sealing performance.

[0054] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An auxiliary pressure-bearing and unsealing mechanism, characterized in that, Includes a soluble limiting compensation sleeve (100), an elastic expansion main shoulder protector (200), and an elastic expansion supplementary shoulder protector (300). The soluble limiting compensation sleeve (100) is inserted into the elastic expansion main shoulder protector (200), the elastic expansion supplementary shoulder protector (300) is fitted into the elastic expansion main shoulder protector (200), and the soluble limiting compensation sleeve (100) is fitted into the expansion tube (3). The soluble limiting compensation sleeve (100) is configured to expand with the expanding tube (3) and dissolve after expansion; The elastic expansion main shoulder protector (200) and the elastic expansion supplementary shoulder protector (300) abut against the shoulder of the expansion tube (3) after the expansion tube (3) expands. When unsealed, they assist the expansion tube (3) to retract under their own elastic force. It also includes a shoulder protector cap (400), which is fitted onto the elastic expansion main shoulder protector (200) and the elastic expansion supplementary shoulder protector (300). With the side of the elastic expansion main shoulder protector (200) and the elastic expansion supplementary shoulder protector (300) near the shoulder of the expansion tube (3) as the expansion end, there is an expansion space (a) between the expansion end of the elastic expansion supplementary shoulder protector (300) and the outer cap of the shoulder protector (400). The elastic expansion main shoulder (200) has multiple first slits (210) evenly distributed along the circumference at its expansion end, forming an elastic cantilever beam; The elastic expansion filler shoulder (300) has multiple second slits (310) evenly distributed along the circumference at its expansion end, forming an elastic cantilever beam; The first slit (210) and the second slit (310) are arranged alternately; The side wall of the soluble limiting compensation sleeve (100) is provided with a through cut (110). The soluble limiting compensation sleeve (100) has a soluble surface (120) on its outer side, and the soluble surface (120) is covered by the elastic expansion main shoulder protector (200).

2. The auxiliary pressure-bearing and unsealing mechanism according to claim 1, characterized in that, The soluble limiting compensation sleeve (100) is made of magnesium-aluminum alloy.

3. The auxiliary pressure-bearing and unsealing mechanism according to claim 2, characterized in that, The soluble limiting compensation sleeve (100) is interference-fitted with the elastic expansion main shoulder guard (200).

4. The auxiliary pressure-bearing and unsealing mechanism according to claim 3, characterized in that... The expansion end of the elastic expansion main shoulder guard (200) is provided with a first flange (220), which abuts against the shoulder of the expansion tube (3).

5. The auxiliary pressure-bearing and unsealing mechanism according to claim 4, characterized in that, The expansion end of the elastic expansion supplement shoulder guard (300) is provided with a second flange (320), and the second flange (320) abuts against the first flange (220).

6. An expanded packer, characterized in that, Includes the auxiliary pressure-bearing and unsealing mechanism as described in any one of claims 1-5.

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