Degradable easy-to-unseal packer

Abstract

The utility model discloses a degradable easy-to-unseal packer, including upper joint, center tube and lower joint, the upper joint is connected on the upper end of center tube, and the upper joint is connected with degradable sealing mechanism, the degradable sealing mechanism includes the upper compression ring, rubber cylinder and lower compression ring that connect in proper order, the upper compression ring is connected the upper joint, and the rubber cylinder is set up in the outer wall of center tube, and the lower compression ring is connected with step locking mechanism, the piston cylinder structure is set up on the lateral wall of center tube, and the piston cylinder structure includes upper piston, lower piston and vice piston, and the upper piston and step locking mechanism bottom are set up with upper setting sealing cylinder, and the upper setting sealing cylinder is connected with lower setting sealing cylinder, and the upper setting sealing cylinder and lower setting sealing cylinder are set up in the outer wall of lower piston, the locking groove of center tube lower extreme is provided with lock block, and the outer wall of vice piston is connected with lower setting sealing cylinder inner chamber, and vice piston is set up in the outer wall of lower joint, the utility model discloses adopting degradable sealing mechanism can degrade naturally after completing the work task, and need not complex fishing operation.

Description

Technical Field

[0001] This utility model relates to downhole packers for oil, gas and water wells in the field of oil production engineering technology, and particularly to a biodegradable and easily unpackable packer. Background Technology

[0002] Packers have a multifaceted use and importance in the oil industry. As a technology used since the mid-20th century, their primary function is to create a seal or barrier between different sections of an oil well to prevent fluid flow. In well injection operations, packers are used to ensure that injected material enters only the designated production layer and does not leak into other layers or back to the surface. Furthermore, the use of packers protects the formation from damage, provides pressure control, and helps stabilize the well's structure.

[0003] As downhole operating conditions become increasingly complex, packer design is constantly being innovated to meet higher temperature and pressure requirements. Packers are indispensable tools in the oil and gas industry; their innovation and application improve the efficiency of oil and gas well production, ensure the safety of production operations, and play a crucial role in managing downhole resources.

[0004] However, common problems encountered with packers in application include being unable to move or function properly due to gravel burial; poor flowability, preventing fluid from passing smoothly through the packer and affecting well production; ineffective wellbore sealing, leading to oil and gas leaks or contaminants entering the producing formation; and the possibility of the packer getting stuck in the well, hindering normal operation and maintenance, increasing operational difficulty and costs. Overall, these problems not only slow down operational efficiency but also increase operational complexity and risk.

[0005] Therefore, this utility model solves the common problems of the above-mentioned packers and proposes a degradable and easily desealable packer. Utility Model Content

[0006] The purpose of this invention is to provide a biodegradable and easily unsealed packer. The packer employs two unsealing methods: conventional unsealing by lifting the tubing string and unsealing by dissolving the pressure ring and rubber sleeve, which are soluble in chloride ions. Furthermore, the structure of the packer is improved by using large chamfers on both the upper and lower parts of the large diameter section and placing the rubber sleeve at the upper end to improve its passability and prevent sand burial and well jamming. This achieves simple and reliable on-site setting and unsealing, as well as convenient and efficient construction, overcoming the shortcomings of existing technologies.

[0007] To achieve the above objectives, the present invention provides the following technical solution: This utility model provides a biodegradable and easily desealable packer, comprising an upper connector, a central tube, and a lower connector; The upper connector is snapped onto the upper end of the central tube, and the upper connector is connected to a biodegradable sealing mechanism; the biodegradable sealing mechanism includes an upper pressure ring, a rubber sleeve and a lower pressure ring connected in sequence, the upper pressure ring is connected to the upper connector, the rubber sleeve is sleeved on the outer wall of the central tube, and the lower pressure ring is connected to a stepping locking mechanism; A piston cylinder structure is fitted on the central tube and below the stepping locking mechanism. The piston cylinder structure includes an upper piston, a lower piston, and a secondary piston. An upper setting cylinder is fitted on the outer wall of the bottom of the upper piston and the stepping locking mechanism. The upper setting cylinder is connected to a lower setting cylinder. The upper and lower setting cylinders are fitted on the outer wall of the lower piston. A locking block that engages with the lower piston is provided in the locking groove at the lower end of the central tube. The outer wall of the secondary piston is connected to the inner cavity of the lower setting cylinder. The secondary piston is fitted on the outer wall of the lower connector.

[0008] Furthermore, the stepping locking mechanism is located at the lower end of the limiting step of the central tube. The stepping locking mechanism includes a locking spring, a locking spring seat, and a locking sleeve. The locking spring is installed inside the locking spring seat. The locking sleeve has a stepped structure. The upper part of the locking sleeve extends to the locking spring and the locking spring seat. The lower outer wall of the locking sleeve is nested in the upper inner cavity of the upper seat cylinder. The lower inner cavity of the locking sleeve is connected to the outer wall of the central tube. Two rubber rings are installed on both the lower outer wall and the lower inner cavity of the locking sleeve. The first liquid inlet in the central tube is located at the gap between the locking sleeve and the upper piston. The locking spring, the locking spring seat, and the locking sleeve are fixedly connected by a release shear pin.

[0009] Furthermore, a lower cap is provided on the outer wall of the lower connector to restrict the downward movement of the lower setting cylinder.

[0010] Furthermore, the outer wall of the central tube is of non-uniform diameter, while the inner cavity is of uniform diameter. The upper outer wall of the central tube is threadedly connected to the lower half of the inner cavity of the upper connector, and the lower end of the upper connector is locked onto the upper end of the limiting step of the central tube.

[0011] Furthermore, the upper setting cylinder has a stepped structure, and the lower end of the stepped upper setting cylinder is fixedly connected to the upper end of the lower setting cylinder by a nut.

[0012] Furthermore, the lower piston has a convex-shaped structure, and the outer wall of the upper end of the lower piston limiting step is connected to the inner cavity of the lower end of the upper seat cylinder. The protrusion of the lower piston restricts the downward movement of the upper seat cylinder.

[0013] Furthermore, the lower end of the inner cavity of the lower piston has a groove structure that engages with the locking block, and the locking block is located in the locking groove of the central tube to restrict the downward movement of the locking block.

[0014] Furthermore, the inner cavity of the lower piston is connected to the outer wall of the central tube, and the outer wall of the lower piston with the maximum diameter is connected to the inner cavity of the lower setting cylinder; the outer wall of the lower end of the lower piston limiting step is fixedly connected to the upper end of the auxiliary piston through a setting start shear pin.

[0015] Furthermore, the outer wall of the auxiliary piston is connected to the inner cavity of the lower seat cylinder, and the inner cavity of the auxiliary piston is connected to the upper outer wall of the lower connector; two rubber rings are respectively installed on the lower outer wall of the auxiliary piston and the lower inner cavity of the auxiliary piston in a staggered manner.

[0016] Furthermore, the upper piston is fixedly connected to the central tube by a split nut.

[0017] Compared with the prior art, the present invention has the following beneficial technical effects: This invention provides a biodegradable and easily unsealable packer. The biodegradable sealing mechanism allows for natural degradation after the packer completes its work, eliminating the need for complex retrieval operations, reducing operational procedures and costs, and minimizing the impact on the downhole environment. The hydraulic setting mechanism, featuring a step-locking mechanism combined with a piston-cylinder structure, ensures stable compression of the packer during setting without rebound, effectively isolating the tubing from the casing annulus and meeting the sealing requirements of oil and gas extraction operations. This biodegradable and easily unsealable packer offers two unsealing methods: conventional tubing string lifting for unsealing, and a dissolution unsealing method using chloride ions to dissolve the biodegradable sealing mechanism formed by the pressure ring and packer. After complete dissolution, the maximum outer diameter of the remaining steel portion of the packer is much smaller than the inner diameter of the casing, allowing for easy removal from the casing and preventing well jamming. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of a biodegradable and easily desealable packer according to an embodiment of the present invention.

[0019] In the diagram: 1. Upper connector, 2. Upper pressure ring, 3. Rubber sleeve, 4. Central tube, 5. Lower pressure ring, 6. Locking spring, 7. Unsealing shear pin, 8. Locking spring seat, 9. Lock sleeve, 10. Upper piston, 11. Split nut, 12. Upper setting cylinder, 13. Lower piston, 14. Lower setting cylinder, 15. Locking block, 16. Setting starting shear pin, 17. Auxiliary piston, 18. Lower spare cap, 19. Lower connector. Detailed Implementation

[0020] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of this invention. Therefore, the drawings and description are considered exemplary in nature and not restrictive.

[0021] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0022] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0023] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0024] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0025] It should be understood that, when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0026] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the scope of the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0027] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0028] The accompanying drawings show various structural schematic diagrams according to embodiments of the present invention. These drawings are not to scale, and some details have been enlarged and may have been omitted for clarity. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0029] See Figure 1 This utility model provides a biodegradable and easily unsealable packer, comprising an upper connector 1, a biodegradable sealing mechanism, a central tube 4, a piston cylinder structure, a stepping locking mechanism, and a lower connector 19; the biodegradable sealing mechanism includes an upper pressure ring 2, a rubber sleeve 3, and a lower pressure ring 5, all of which are soluble in chloride ions; the stepping locking mechanism includes a locking spring 6, a locking spring seat 8, and a locking sleeve 9; the piston cylinder structure includes an upper piston 10, an upper setting cylinder 12, a lower piston 13, and a lower setting cylinder 14; The upper connector 1 and the lower connector 19 are respectively connected to both ends of the central tube 4 by threads. The biodegradable sealing mechanism consists of an upper pressure ring 2, a rubber sleeve 3, and a lower pressure ring 5 connected in sequence. The upper pressure ring 2 is connected to the upper connector 1, the rubber sleeve 3 is sleeved on the outer wall of the central tube 4, and the lower pressure ring 5 is connected to the step locking mechanism. The three components achieve a seal between the tubing and the casing annulus through compression deformation during setting. The mechanism is biodegradable after the work is completed, avoiding the need for subsequent salvage operations. The outer wall of the central tube 4 has a non-uniform diameter, while the inner cavity has a uniform diameter. In this embodiment, the inner cavity diameter is 50mm to ensure stable transmission of the internal fluid and to provide an installation base and movement track for other components. The upper end of the central tube 4 is connected to the upper connector 1, and the central tube 4 is connected to the lower connector 19. The step locking mechanism is installed at the lower end of the limiting step of the central tube 4. A piston cylinder structure is fitted on the side wall of the central tube 4 and below the stepping locking mechanism. The piston cylinder structure includes an upper piston 10, a lower piston 13 and a secondary piston 17. An upper setting cylinder 12 is fitted on the outer wall of the upper piston 10 and the bottom of the stepping locking mechanism. The upper setting cylinder 12 is connected to the lower setting cylinder 14. The upper setting cylinder 12 and the lower setting cylinder 14 are fitted on the outer wall of the lower piston 13. During setting, the rubber cylinder 3 is compressed by hydraulically pushing it upward. A locking block 15 is provided in the locking groove at the lower end of the central tube 4, which engages with the lower piston 13. The locking block 15 is engaged in the locking groove of the central tube 4 and engages with the lower piston 13, restricting the lower piston 13 from moving downward. The inner cavity of the lower piston 13 is connected to the outer wall of the central tube 4, and the outer wall of the lower piston 13 with the maximum diameter is connected to the inner cavity of the lower setting cylinder 14. The lower outer wall of the limiting step of the lower piston 13 is fixedly connected to the upper end of the auxiliary piston 17 through the setting start shear pin 16, which is sheared when the hydraulic pressure reaches a certain level, triggering the setting action.

[0030] In some preferred embodiments of this utility model, the step locking mechanism is disposed at the lower end of the limiting step of the central tube 4. The step locking mechanism includes a locking spring 6, a locking spring seat 8, and a locking sleeve 9. The locking spring seat 8 is fixed at the lower end of the limiting step of the central tube 4, providing an installation position for the locking spring 6. The locking spring 6 is installed in the locking spring seat 8 and engages with the locking sleeve 9 during setting to achieve step locking and prevent the rubber sleeve 3 from rebounding. The locking sleeve 9 has a stepped structure, with the upper part of the locking sleeve 9 extending to the locking spring 6 and the locking spring seat 8, and the lower outer wall of the locking sleeve 9 nested in... In the upper inner cavity of the upper setting cylinder 12, the lower inner cavity of the locking sleeve 9 is connected to the outer wall of the central tube 4 to transmit motion and pressure. The lower outer wall of the locking sleeve 9 and the lower inner cavity of the locking sleeve 9 are each equipped with two rubber rings to ensure reliable sealing between the locking sleeve 9 and the upper setting cylinder 12 and the central tube 4. The first liquid inlet in the central tube 4 is located in the gap between the locking sleeve 9 and the upper piston 10 to transmit hydraulic start-up setting. The locking spring 6, the locking spring seat 8 and the central tube 4 are fixedly connected by the unsealing shear pin 7. The locking can be released by cutting the unsealing shear pin 7 during unsealing.

[0031] In some preferred embodiments of this utility model, a lower cap 18 is provided on the outer wall of the lower connector 19 to restrict the downward movement of the lower setting cylinder 14. The lower connector 19 is threadedly connected to the lower end of the central tube 4, providing connection and support for the lower part of the packer. The lower cap 18 is installed on the outer wall of the lower connector 19, and through mechanical limiting, it ensures the stability of the position of the lower setting cylinder 14 during the setting process, preventing it from moving downward and affecting the setting effect and the normal cooperation of various components.

[0032] In some preferred embodiments of this utility model, the upper setting cylinder 12 has a stepped structure, and the lower end of the stepped upper setting cylinder 12 is fixedly connected to the upper end of the lower setting cylinder 14 by a nut. The upper setting cylinder 12 is sleeved on the outer wall of the locking sleeve 9 and the upper piston 10. The stepped structure of the upper setting cylinder 12 and the lower setting cylinder 14 cooperate with each other and are connected by a nut to form a whole. During setting, the two are hydraulically pushed upward to compress the rubber cylinder 3.

[0033] In some preferred embodiments of this utility model, the lower piston 13 has a convex-shaped structure. The outer wall of the upper end of the limiting step of the lower piston 13 is connected to the stepped lower end of the inner cavity of the upper setting cylinder 12. The protrusion of the lower piston 13 restricts the downward movement of the upper setting cylinder 12. The convex-shaped structure of the lower piston 13 cooperates with the upper setting cylinder 12, the limiting step achieves the connection with the upper setting cylinder 12, and the protrusion prevents the upper setting cylinder 12 from moving downward by means of mechanical limiting. At the same time, the groove at the lower end of the inner cavity of the lower piston 13 engages with the locking block 15 to further control its own movement. The lower end of the inner cavity of the lower piston 13 has a groove structure that engages with the locking block 15. The locking block 15 is located in the locking groove of the central tube 4 to restrict the downward movement of the locking block 15. The locking block 15 is engaged in the locking groove of the central tube 4 and engaged with the groove at the lower end of the inner cavity of the lower piston 13 to form a mechanical limiting structure, which restricts the downward movement of the lower piston 13 during the setting process and ensures that the lower piston 13 moves along a predetermined trajectory. The inner cavity of the lower piston 13 is connected to the outer wall of the central tube 4, and the outer wall of the lower piston 13 with the maximum diameter is connected to the inner cavity of the lower setting cylinder 14. The lower outer wall of the limiting step of the lower piston 13 is fixedly connected to the upper end of the auxiliary piston 17 through the setting start shear pin 16. The lower piston 13, through its connection with the central tube 4 and the lower setting cylinder 14, serves as a key component for force transmission and motion control during the setting process. The lower piston 13 is connected to the auxiliary piston 17 through the setting start shear pin 16. When the auxiliary piston 17 shears the setting start shear pin 16 and moves downward under hydraulic pressure, it drives the lower piston 13 to move upward, thereby pushing the upper setting cylinder 12, the lower setting cylinder 14, and other components to compress the rubber sleeve 3 to achieve setting.

[0034] In some preferred embodiments of this utility model, the outer wall of the auxiliary piston 17 is connected to the inner cavity of the lower setting cylinder 14, and the inner cavity of the auxiliary piston 17 is connected to the upper outer wall of the lower connector 19; two rubber rings are respectively installed on the lower outer wall of the auxiliary piston 17 and the lower inner cavity of the auxiliary piston 17 in a staggered manner. When the auxiliary piston 17 is subjected to hydraulic pressure, it moves downward to the protrusion on the outer wall of the lower connector 19. At this time, the lower piston 13 pushes the upper setting cylinder 12, the lower setting cylinder 14, the locking sleeve 9, and the lower pressure ring 5 to move upward to compress the rubber sleeve 3. When the rubber sleeve 3 is compressed to a certain extent and no longer changes, the position of the lower end of the lower setting cylinder 14 moving upward never exceeds the position of the second sealing rubber ring of the auxiliary piston, so as to ensure reliable sealing.

[0035] In some preferred embodiments of this utility model, the upper piston 10 is fixedly connected to the central tube 4 by a split nut 11. The upper piston 10 is fixed to the central tube 4 by the split nut 11, which restricts the downward movement of the locking sleeve 9. The rubber rings on the outer wall and inner cavity of the upper piston 10 serve a sealing function to prevent hydraulic leakage.

[0036] During setting, the packer is lowered to the designated position in the wellbore. Pressure is applied from the surface into the tubing, causing the auxiliary piston 17 to shear off the setting initiator shear pin 16 and move downwards. At this time, the locking block 15 can smoothly exit the locking groove of the central tube 4. Under hydraulic pressure, the lower piston 13, upper setting cylinder 12, and locking sleeve 9 separate from the central tube 4 and move upwards, pushing the biodegradable lower pressure ring to compress the rubber sleeve. The locking spring 6, locking spring seat 8, and central tube 4, along with the locking sleeve 9, form a step-locking mechanism. This mechanism employs a mature wellhead resistance design to prevent the rubber sleeve from rebounding and achieve a seal, making it highly efficient and reliable for setting operations.

[0037] During unsealing, the packer of this invention employs two unsealing methods: the conventional tubing-lifting unsealing method, which involves lifting the tubing, pulling the upper connector 1 and the central tube 4 upwards, thereby shearing the unsealing shear pin 7. At this time, the anti-rebound mechanism formed by the locking spring 6 and the locking sleeve 9 fails. With continued lifting, the locking spring seat 8 separates from the central tube 4, and the central tube 4 continues to move downwards, allowing the rubber sleeve to be recovered and unsealed; and the chloride-soluble dissolution unsealing method, which utilizes materials soluble in chloride ions, including the biodegradable upper pressure ring 2, biodegradable rubber sleeve 3, and biodegradable lower pressure ring 5, which are all made of materials soluble in chloride ions, and completely degrade within 10 days after operation. At this time, the maximum outer diameter of the remaining steel body of the packer is 94mm, which is much smaller than the inner diameter of the casing, allowing it to be easily removed from the casing. This method combines tubing-lifting unsealing with rubber sleeve dissolution unsealing, preventing well jamming. Based on this, the structure of the packer was improved, mainly by selecting large chamfers at both the top and bottom of the large diameter section and placing the rubber sleeve at the top, which improves its passability and prevents sand burial and well jamming, thus achieving simple and reliable on-site setting and unsealing, and convenient and efficient construction.

[0038] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed utility model. The scope of protection of this utility model is defined by the appended claims and their equivalents.

Claims

1. A biodegradable and easily desealable packer, characterized in that, It includes an upper connector (1), a central tube (4), and a lower connector (19). The upper connector (1) is snapped onto the upper end of the central tube (4), and the upper connector (1) is connected to a biodegradable sealing mechanism; the biodegradable sealing mechanism includes an upper pressure ring (2), a rubber sleeve (3) and a lower pressure ring (5) connected in sequence, the upper pressure ring (2) is connected to the upper connector (1), the rubber sleeve (3) is sleeved on the outer wall of the central tube (4), and the lower pressure ring (5) is connected to a stepping locking mechanism; A piston cylinder structure is fitted on the side wall of the central tube (4) and below the stepping locking mechanism. The piston cylinder structure includes an upper piston (10), a lower piston (13), and a secondary piston (17). An upper seat cylinder (12) is fitted at the bottom of the upper piston (10) and the stepping locking mechanism. The upper seat cylinder (12) is connected to a lower seat cylinder (14). The upper seat cylinder (12) and the lower seat cylinder (14) are fitted on the outer wall of the lower piston (13). A locking block (15) that engages with the lower piston (13) is provided in the locking groove at the lower end of the central tube (4). The outer wall of the secondary piston (17) is connected to the inner cavity of the lower seat cylinder (14). The secondary piston (17) is fitted on the outer wall of the lower connector (19).

2. The biodegradable and easily desealable packer according to claim 1, characterized in that, The stepping locking mechanism is located at the lower end of the limiting step of the central tube (4). The stepping locking mechanism includes a locking spring (6), a locking spring seat (8), and a locking sleeve (9). The locking spring (6) is installed in the locking spring seat (8). The locking sleeve (9) has a stepped structure. The upper part of the locking sleeve (9) extends to the locking spring (6) and the locking spring seat (8). The lower outer wall of the locking sleeve (9) is nested in the upper inner cavity of the upper seat cylinder (12). The lower inner cavity of the locking sleeve (9) is connected to the outer wall of the central tube (4). The lower outer wall of the locking sleeve (9) and the lower inner cavity of the locking sleeve (9) are each equipped with two rubber rings. The first liquid inlet hole in the central tube (4) is located in the gap between the locking sleeve (9) and the upper piston (10). The locking spring (6), the locking spring seat (8), and the locking sleeve (9) are fixedly connected by the unsealing shear pin (7).

3. The biodegradable and easily desealable packer according to claim 2, characterized in that, The lower connector (19) is provided with a lower cap (18) on its outer wall to restrict the downward movement of the lower seat cylinder (14).

4. The biodegradable and easily desealable packer according to claim 3, characterized in that, The outer wall of the central tube (4) is of non-uniform diameter, while the inner cavity is of uniform diameter. The upper outer wall of the central tube (4) is threadedly connected to the lower half of the inner cavity of the upper connector (1). The lower end of the upper connector (1) is stuck on the upper end of the limiting step of the central tube (4).

5. A biodegradable and easily desealable packer according to claim 4, characterized in that, The upper setting cylinder (12) has a stepped structure, and the lower end of the upper setting cylinder (12) is fixedly connected to the upper end of the lower setting cylinder (14) by a nut.

6. The biodegradable and easily desealable packer according to claim 5, characterized in that, The lower piston (13) has a convex shape. The upper outer wall of the limiting step of the lower piston (13) is connected to the stepped lower inner cavity of the upper seat cylinder (12). The protrusion of the lower piston (13) restricts the downward movement of the upper seat cylinder (12).

7. A biodegradable and easily desealable packer according to claim 6, characterized in that, The lower end of the inner cavity of the lower piston (13) has a groove structure that engages with the locking block (15). The locking block (15) is located in the locking groove of the central tube (4) to restrict the downward movement of the locking block (15).

8. A biodegradable and easily desealable packer according to claim 7, characterized in that, The inner cavity of the lower piston (13) is connected to the outer wall of the central tube (4), and the outer wall of the maximum diameter of the lower piston (13) is connected to the inner cavity of the lower seat cylinder (14); the lower outer wall of the limiting step of the lower piston (13) is fixedly connected to the upper end of the auxiliary piston (17) through the seat start shear pin (16).

9. A biodegradable and easily desealable packer according to claim 8, characterized in that, The outer wall of the auxiliary piston (17) is connected to the inner cavity of the lower seat cylinder (14), and the inner cavity of the auxiliary piston (17) is connected to the upper outer wall of the lower connector (19); two rubber rings are installed on the lower outer wall of the auxiliary piston (17) and the lower inner cavity of the auxiliary piston (17) respectively in a staggered manner.

10. A biodegradable and easily desealable packer according to claim 9, characterized in that, The upper piston (10) is fixedly connected to the central tube (4) by a split nut (11).

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