Self-anchored balanced expansion packer

Abstract

The present invention belongs to the technical field of packers, and specifically relates to a self-anchored balanced expansion packer, which aims to solve the problem that the existing packer has a large upward pressure action area, and the downward force generated by the upward pressure, which is equivalent to the unsealing force, is also large, resulting in poor upward pressure bearing capacity of the packer. The self-anchored balanced expansion packer in the present invention includes a center tube, an upper joint sleeved on the upper part of the center tube, an unsealing sleeve located on the outer periphery of the center tube, and a balancing piston located between the center tube and the unsealing sleeve; the upper joint and the unsealing sleeve are connected by unsealing shear nails; the lower part of the unsealing sleeve is provided with an extension section, and a gap is formed between the extension section and the center tube, and the balancing piston is located in the gap between the extension section and the center tube, and its axial radial movement is limited by a limit mechanism. The packer is designed with a balancing piston, and the upward pressure action area is reduced, thereby improving the upward pressure bearing capacity of the packer and making it easier to unseal.

Description

Technical Field

[0001] The invention belongs to the technical field of packers, and in particular relates to a self-anchored balanced expansion packer. Background Art

[0002] In production, the completion string often uses a single sleeve to hold the pressure to seal the packer. Sometimes the sleeve opens in advance, resulting in incomplete sealing of the packer. The completion string uses an expansion packer, which has a large pressure acting area on the packer. The downward force generated by the pressure is also large, which is equivalent to the unsealing force, resulting in poor pressure bearing capacity of the packer.

[0003] In addition, in corrosive and scaling wells, the exposed end of the lower center pipe is prone to scaling, resulting in the lower end joint of the rubber sleeve not being able to move downward smoothly or not being able to effectively relieve pressure after the shear pins of the packer are broken. The liquid in the packer capsule cannot be discharged smoothly, and the packer cannot be released smoothly, which can easily lead to a major overhaul of the pipe string. Summary of the invention

[0004] The invention provides a self-anchored balanced expansion packer to alleviate the problem that the existing packer has a large up-pressure action area and a large downward force equivalent to a release force generated by the up-pressure, resulting in poor up-pressure bearing capacity of the packer.

[0005] In order to alleviate the above technical problems, the technical solution provided by the present invention is:

[0006] A self-anchored balanced expansion packer comprises a center tube, an upper joint sleeved on the upper part of the center tube, a release sleeve located on the outer periphery of the center tube, and a balance piston located between the center tube and the release sleeve; the upper joint and the release sleeve are connected by release shear pins; an extension section is provided at the lower part of the release sleeve, a gap is provided between the extension section and the center tube, the balance piston is located in the gap between the extension section and the center tube, and its radial movement is limited by a limit mechanism.

[0007] Furthermore, it also includes a locking sleeve arranged in the gap formed by the extended section and the central tube, and the lower part of the extended section is connected to the locking sleeve by bolts; the locking sleeve has a locked state in which it is locked with the central tube through a locking mechanism, and the locking sleeve has an unlocked state in which it is unlocked from the central tube after the locking mechanism is unlocked.

[0008] Furthermore, the locking mechanism includes a locking steel column arranged in a transversely penetrating through groove of the locking sleeve and a locking groove arranged on the outer wall of the center tube; after the locking steel column moves laterally and is engaged with the locking groove under the lateral thrust of the downward movement of the balancing piston, the locking sleeve is in a locked state; after the locking steel column loses the thrust of the balancing piston, the locking sleeve is in an unlocked state.

[0009] Furthermore, an extension section is provided at the lower part of the balancing piston, and a protruding section is provided at the top of the locking sleeve, and a gap is provided between the protruding section and the unsealing sleeve; when the extension section is inserted into the gap between the protruding section and the unsealing sleeve, the limiting mechanism limits the radial movement of the balancing piston and has a tendency to drive the balancing piston to move upward.

[0010] Furthermore, the limiting mechanism includes a retaining ring located at the top of the raised section and an anti-disc spring located directly above the retaining ring; there is a gap between the anti-disc spring and the unsealing sleeve, and the extending section can be inserted into the gap between the anti-disc spring and the unsealing sleeve, and under the action of external force, the balancing piston compresses the anti-disc spring, and at the same time, the extending section of the balancing piston is further inserted into the gap between the raised section and the unsealing sleeve.

[0011] Furthermore, the upper joint and the unsealing sleeve are connected through a step structure, and the unsealing shear nails penetrate the unsealing sleeve and are connected to the upper joint; the central pipe and the upper joint are connected by bolts.

[0012] Furthermore, it also includes a liquid inlet sealing piston, a return spring, a connecting sleeve, a rubber sleeve upper end joint, and a rubber sleeve which are sequentially sleeved on the center tube and located at the lower end of the locking sleeve; the liquid inlet sealing piston and the return spring are located in the annulus formed by the center tube, the locking sleeve and the connecting sleeve; the upper end face of the liquid inlet sealing piston is in close contact with the lower end face of the locking sleeve, the lower end face of the liquid inlet sealing piston is in close contact with the upper end face of the return spring, and the lower end face of the return spring is in close contact with the step surface of the connecting sleeve; a liquid inlet hole is provided on the center tube, and the liquid inlet hole is connected to the annulus between the locking sleeve and the center tube; the return spring is configured to be in a compressed state and always has a tendency to drive the liquid inlet sealing piston to move upward to close the liquid inlet sealing channel.

[0013] Furthermore, it also includes a lower end joint of the rubber cartridge and a lower sealing plug arranged at the lower end of the rubber cartridge; the lower end surface of the step inside the lower end joint of the rubber cartridge is in close contact with the upper end surface of the lower sealing plug, the lower part of the lower sealing plug is provided with a groove and there is a gap between it and the center tube, and a square sealing ring is provided at the bottom of the gap; the center tube, the lower sealing plug and the square sealing ring form an oil-filled sealing cavity.

[0014] Furthermore, it also includes a pressure relief groove arranged on the outer wall of the central tube; the pressure relief groove is arranged directly below the square sealing ring; and a non-metallic coating is coated on the outer wall of the central tube between the square sealing ring and the lower joint.

[0015] A setting system using the above-mentioned self-anchored balanced expandable packer includes a first-stage sliding sleeve arranged at the lower part of the self-anchored balanced expandable packer in the casing and a second-stage sliding sleeve located below the first-stage sliding sleeve, wherein the inner diameter of the first-stage sliding sleeve is greater than the inner diameter of the second-stage sliding sleeve.

[0016] The beneficial effects of the present invention are analyzed as follows:

[0017] A self-anchored balanced expansion packer comprises a center tube, an upper joint sleeved on the upper part of the center tube, a release sleeve located on the outer periphery of the center tube, and a balance piston located between the center tube and the release sleeve; the upper joint and the release sleeve are connected by release shear pins; an extension section is provided at the lower part of the release sleeve, a gap is provided between the extension section and the center tube, the balance piston is located in the gap between the extension section and the center tube, and its radial movement is limited by a limit mechanism.

[0018] After the packer is set, an annular pressure (referred to as upper pressure P) is generated between the upper oil pipe and the casing. Conventional packers are not designed with a balancing piston, and the force generated by the upper pressure P is F1 = 0.785*P*(D3^2-D1^2) (D1 is the inner diameter length of the center pipe, and D3 is the inner diameter length of the casing). The packer provided by the present invention is designed with a balancing piston, and the force generated by the upper pressure P is F2 = 0.785*(D3^2-D2^2) (D2 is the inner diameter length of the extended section of the unpacking sleeve, D 3 is the inner diameter of the casing), and the design dimensions D1=60mm, D2=100mm, and D3=124mm are often taken in tool design, so F1=9244P, F2=4220P, and F1:F2=2.2:1. After designing the balanced piston, the upper pressure action area is reduced, and the force generated is reduced by about 55%. With the same design pressure bearing capacity of the packer, the force on the unsealing shear pins is reduced by 55%. The packer has a stronger pressure bearing capacity, higher reliability, and is easier to unseal. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the related technologies, the drawings required for use in the specific embodiments or the related technical descriptions will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 A schematic structural diagram of a self-anchored balanced expandable packer in an upper pressure state provided by an embodiment of the present invention;

[0021] Figure 2 yes Figure 3 Sectional view of the AA position of the self-anchored balanced expansion packer;

[0022] Figure 3 A schematic structural diagram of a self-anchored balanced expansion packer in an initial well-entering state provided by an embodiment of the present invention;

[0023] Figure 4 A schematic structural diagram of a self-anchored balanced expandable packer in a setting state provided by an embodiment of the present invention;

[0024] Figure 5A schematic structural diagram of a self-anchored balanced expansion packer in an unsealed state provided by an embodiment of the present invention;

[0025] Figure 6 A schematic diagram of a completion string operation provided by an embodiment of the present invention;

[0026] icon:

[0027] 10-center tube; 20-upper joint; 30-unsealing sleeve; 40-balance piston; 50-unsealing shear nail; 60-anti-disc spring; 70-circlip; 80-locking sleeve; 90-locking steel column; 100-casing; 110-liquid inlet sealing piston; 120-reset spring; 130-connecting sleeve; 140-rubber cylinder upper end joint; 150-rubber cylinder; 160-rubber cylinder lower end joint; 170-lower sealing plug ;180-square sealing ring;190-lower joint;200-oil filling plug;220-first stage ball;230-second stage ball;240-first stage sliding sleeve;250-second stage sliding sleeve;260-self-anchored balanced expansion packer;31-extending section;41-inserting section;81-convex section;01-locking groove;02-sealing chamber;03-liquid inlet hole;04-pressure relief groove;05-non-metallic coating. DETAILED DESCRIPTION

[0028] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described implementation is only a part of the implementation of the present invention, not all of the implementation. Based on the implementation of the present invention, all other implementations obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance. Physical quantities in formulas, if not separately marked, should be understood as basic quantities of the base units of the International System of Units, or derived quantities derived from the basic quantities through mathematical operations such as multiplication, division, differentiation or integration.

[0030] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0031] In production, the completion string often uses a single sleeve to hold the pressure to seal the packer. Sometimes the sleeve opens in advance, resulting in incomplete sealing of the packer. The completion string uses an expansion packer, which has a large pressure acting area on the packer. The downward force generated by the pressure is also large, which is equivalent to the unsealing force, resulting in poor pressure bearing capacity of the packer.

[0032] In view of this, the present invention provides a self-anchored balanced expansion packer 260, please refer to Figures 1 to 6 The packer includes a center pipe 10, an upper joint 20 sleeved on the upper part of the center pipe 10, a release sleeve 30 located on the outer periphery of the center pipe 10, and a balance piston 40 located between the center pipe 10 and the release sleeve 30; the upper joint 20 and the release sleeve 30 are connected by a release shear nail 50; the lower part of the release sleeve 30 is provided with an extension section 31, and there is a gap between the extension section 31 and the center pipe 10. The balance piston 40 is located in the gap between the extension section 31 and the center pipe 10 and its radial movement is limited by a limiting mechanism.

[0033] After the packer is set, an annular pressure (referred to as upper pressure P) is generated between the upper oil pipe and the casing 100. Conventional packers are not designed with a balancing piston 40, and the force F1 generated by the upper pressure P is 0.785*P*(D3^2-D1^2) (D1 is the inner diameter length of the center pipe 10, and D3 is the inner diameter length of the casing 100). The packer provided by the present invention is designed with a balancing piston 40, and the force F2 generated by the upper pressure P is 0.785*(D3^2-D2^2) (D2 is the inner diameter length of the extension section 31 of the release sleeve 30 Diameter length, D3 is the inner diameter length of casing 100), the design dimensions D1=60mm, D2=100mm, D3=124mm are often taken in tool design, then F1=9244P, F2=4220P, F1:F2=2.2:1, after designing the balancing piston 40, the upper pressure action area is reduced, and the force generated is reduced by about 55%. With the same design bearing capacity of the packer, the force on the unsealing shear nail 50 is reduced by 55%, the packer has stronger bearing capacity of upper pressure, higher reliability, and is easier to unseal.

[0034] In the optional solution of this embodiment, a locking sleeve 80 is further included, which is arranged in the gap formed by the extension section 31 and the central tube 10. The lower part of the extension section 31 is connected to the locking sleeve 80 by bolts. The locking sleeve 80 has a locked state in which it is locked with the central tube 10 through a locking mechanism, and the locking sleeve 80 has an unlocked state in which it is unlocked from the central tube 10 after the locking mechanism is unlocked. When the locking sleeve 80 and the central tube 10 are in the locked state, no matter how high the upward pressure is, the force generated by the upward pressure is transferred to the central tube 10, and the unsealing shear nail 50 is not subjected to force, thereby protecting the unsealing shear nail 50.

[0035] For the shape and structure of the locking mechanism, please refer to Figure 1 and Figure 2 , the specific instructions are as follows:

[0036] The locking mechanism includes a locking steel column 90 arranged in a transversely penetrating groove of the locking sleeve 80 and a locking groove 01 arranged on the outer wall of the center pipe 10; when the packer is sealed, when liquid is injected into the annulus of the casing 100 and the center pipe 10, the balance piston 40 moves downward due to the pressure of the liquid and pushes the locking steel column 90 laterally to move laterally until it is engaged with the locking groove 01, and the locking sleeve 80 and the center pipe 10 are in a locked state; after the locking steel column 90 loses the thrust of the balance piston 40, the locking sleeve 80 and the center pipe 10 are in an unlocked state.

[0037] In an optional scheme of this embodiment, an extension section 41 is provided at the lower part of the balancing piston 40, and a protruding section 81 is provided at the top of the locking sleeve 80, and a gap is provided between the protruding section 81 and the unsealing sleeve 30; when the extension section 41 is inserted into the gap between the protruding section 81 and the unsealing sleeve 30, the limiting mechanism limits the radial movement of the balancing piston 40 and has a tendency to drive the balancing piston 40 to move upward.

[0038] Furthermore, the through groove that passes transversely through the locking sleeve 80 is located at the raised section 81. Therefore, when the extension section 41 of the balance piston 40 is inserted into the gap between the raised section 81 and the unsealing sleeve 30, the extension section 41 pushes the locking steel column 90 laterally to move laterally until it is engaged with the locking groove 01, so that the locking sleeve 80 and the center tube 10 are in a locked state.

[0039] In an optional scheme of this embodiment, the limiting mechanism includes a retaining ring 70 located at the top of the raised section 81 and an anti-disc spring 60 located directly above the retaining ring 70; the retaining ring 70 includes a horizontal plate and a vertical plate vertically connected to the horizontal plate, the horizontal plate is connected to the top wall of the locking sleeve 80, and the vertical plate is connected to the outer wall of the center tube 10, and the retaining ring 70 limits the axial movement of the anti-disc spring 60.

[0040] There is a gap between the anti-disc spring 60 and the unsealing sleeve 30, and the extension section 41 of the balancing piston 40 can be inserted into the gap between the anti-disc spring 60 and the unsealing sleeve 30, and under the action of external force, the balancing piston 40 compresses the anti-disc spring 60. At the same time, the extension section 41 of the balancing piston 40 is further inserted into the gap between the protruding section 81 and the unsealing sleeve 30. When the balancing piston 40 moves downward, it pushes the locking steel column 90 laterally to move laterally until it is engaged with the locking groove 01. The locking sleeve 80 and the center tube 10 are in a locked state. No matter how high the upper pressure is, the force generated by the upper pressure is transferred to the center tube 10, and the unsealing shear pin 50 is not subjected to force, thereby protecting the unsealing shear pin 50.

[0041] In an optional solution of this embodiment, the upper joint 20 and the unsealing sleeve 30 are connected by a step structure, and the unsealing shear nail 50 penetrates the unsealing sleeve 30 and is connected to the upper joint 20; the central pipe 10 and the upper joint 20 are connected by bolts.

[0042] The optional scheme of this embodiment also includes a liquid inlet sealing piston 110, a return spring 120, a connecting sleeve 130, a rubber sleeve upper end joint 140, and a rubber sleeve 150, which are sequentially sleeved on the central tube 10 and located at the lower end of the locking sleeve 80; the liquid inlet sealing piston 110 and the return spring 120 are located in the annulus formed by the central tube 10, the locking sleeve 80 and the connecting sleeve 130; the upper end surface of the liquid inlet sealing piston 110 is in close contact with the lower end surface of the locking sleeve 80, the lower end surface of the liquid inlet sealing piston 110 is in close contact with the upper end surface of the return spring 120, and the lower end surface of the return spring 120 is in close contact with the step surface of the connecting sleeve 130; a liquid inlet hole 03 is provided on the central tube 10, and the liquid inlet hole 03 is connected to the annulus between the locking sleeve 80 and the central tube 10; the return spring 120 is configured to be in a compressed state and always has a tendency to drive the liquid inlet sealing piston 110 to move upward to close the liquid inlet sealing channel.

[0043] For more information on the packer setting process, please refer to Figure 3 and Figure 4 , the specific instructions are as follows:

[0044] The self-anchored balanced expandable packer 260 is lowered together with the completion string. At this time, the self-anchored balanced expandable packer 260 is in an initial state. Figure 3 As shown, after the tubing string is lowered to the designed position, the sealing ball is put into the seat. When the sealing ball reaches the sealing ball seat position, liquid is injected into the central pipe 10. As the pressure increases, the liquid enters the annulus formed by the central pipe 10, the locking sleeve 80 and the connecting sleeve 130 through the liquid inlet hole 03. The liquid inlet sealing piston 110 is compressed by the pressure and the return spring 120 moves downward, thereby opening the liquid inlet sealing channel, and the liquid enters the rubber cylinder 150. The rubber cylinder 150 expands to realize the sealing of the packer, as shown in FIG. Figure 4 shown.

[0045] In corrosion and scaling wells, the exposed lower end of the center pipe is prone to scaling, which causes the lower end joint of the rubber sleeve to fail to move downward smoothly or fail to effectively relieve pressure after the shear pins of the packer are broken. The liquid in the packer capsule cannot be discharged smoothly, and the packer cannot be released smoothly, which can easily lead to a major overhaul of the pipe string.

[0046] In view of this, the self-anchored balanced expansion packer 260 provided in the present invention also includes a rubber sleeve lower end joint 160, a lower sealing plug 170 and a lower joint 190 arranged at the lower end of the rubber sleeve 150; the lower end face of the inner step of the rubber sleeve lower end joint 160 is in close contact with the upper end face of the lower sealing plug 170, the lower part of the lower sealing plug 170 is provided with a groove and there is a gap between it and the central pipe 10, and a square sealing ring 180 is provided at the bottom of the gap, the inner diameter of the square sealing ring 180 is in close contact with the outer wall of the central pipe 10, and the outer diameter of the square sealing ring 180 is in close contact with the inner wall of the lower sealing plug 170, and the central pipe 10, the lower sealing plug 170 and the square sealing ring 180 form an oil-filled sealing chamber 02. Furthermore, an oil filling plug 200 is provided on the through hole of the outer diameter end face of the lower sealing plug 170, and the sealing chamber 02 can be filled with oil by opening the oil filling plug 200. The sealing chamber oil helps to reduce the resistance of the lower end joint 160 of the rubber cylinder to move downward, and prevents scaling after water enters through oil injection, thereby affecting the unsealing.

[0047] Preferably, the square sealing ring 180 is a rubber part, which can ensure that the oil in the sealing chamber does not leak; and when unsealing, the square sealing ring 180 has a small movement resistance, and can smoothly achieve unsealing.

[0048] In addition, the self-anchored balanced expandable packer 260 provided in the present invention also includes a pressure relief groove 04 arranged on the outer wall of the central pipe 10, and the pressure relief groove 04 is arranged directly below the square sealing ring 180; when unsealed, the liquid in the rubber sleeve 150 can be discharged into the annulus between the central pipe 10 and the casing 100 through the pressure relief groove 04. Compared with the existing pressure relief channel that relieves pressure toward the inner central pipe, the self-anchored balanced expandable packer 260 provided in the present invention relieves pressure more smoothly.

[0049] Preferably, the outer wall of the central pipe 10 between the square seal ring 180 and the lower joint 190 is coated with a non-metallic coating 05. The non-metallic coating 05 does not corrode or scale, thereby extending the service life of the packer.

[0050] In an optional solution of this embodiment, the lower joint 190 is threadedly connected to the lower end of the central pipe 10. When the packer is unsealed, the lower end joint 160 of the rubber sleeve, the lower sealing plug 170 and the square sealing ring 180 move downward until the lower sealing plug 170 abuts against the top surface of the lower joint 190.

[0051] For the unsealing process of the self-anchored balanced expansion packer 260, please refer to Figure 5 , the specific instructions are as follows:

[0052] When unsealing is required, the upper joint 20 is lifted, and the upper joint 20 drives the central tube 10 to move upward, and the unsealing shear pin 50 is cut off. As the central tube 10 moves upward, the sealing ring between the lower end joint 160 of the rubber sleeve and the lower sealing plug 170 fails, and the liquid in the rubber sleeve 150 is discharged into the annulus between the central tube 10 and the casing 100 through the pressure relief groove 04, and the rubber sleeve 150 contracts to achieve unsealing.

[0053] Embodiment 2

[0054] A sealing system using the self-anchored balanced expandable packer 260 described in Example 1 includes a first-stage sleeve 240 arranged at the lower part of the self-anchored balanced expandable packer 260 in the casing 100 and a second-stage sleeve 250 located at the lower part of the first-stage sleeve 240, wherein the inner diameter of the first-stage sleeve 240 is greater than the inner diameter of the second-stage sleeve 250.

[0055] For the working process of the setting system, please refer to Figure 6 , the specific instructions are as follows:

[0056] When completing the well, the second stage is launched first, and the second stage ball 230 can pass through the first stage ball seat. If the second stage sliding sleeve 250 is opened in advance, the first stage ball 220 is launched to cooperate with the first stage ball seat to continue the well completion. The double sliding sleeve design forms a "double insurance" and improves the safety performance of the packer in underground operation.

[0057] In combination with the first and second embodiments, the self-anchored balanced expandable packer 260 and the setting system provided in the present invention can achieve the following beneficial effects:

[0058] 1. By designing the balancing piston 40 to reduce the pressure acting area, the packer has the same designed pressure bearing capacity, and the force on the unsealing shear pin 50 is reduced, so the packer has a stronger pressure bearing capacity and is easier to unseal;

[0059] 2. When the upper pressure is high, the locking mechanism locks the central pipe 10 and the locking sleeve 80. No matter how high the upper pressure is, the force generated by the upper pressure is transferred to the central pipe 10, and the unsealing shear pins 50 are not subjected to force, so the reliability of the packer is higher;

[0060] 3. The square sealing ring 180 ensures that the oil in the sealing chamber does not leak. When unsealing, the square sealing ring 180 of the rubber part has little movement resistance, and unsealing can be achieved smoothly;

[0061] 4. Anti-corrosion design effectively improves the corrosion resistance of the tool;

[0062] 5. The double sliding sleeve design of the tubing string improves the safety performance of the packer in underground operations.

[0063] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements 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. A self-anchored balanced expansion packer, characterized in that: It comprises a central tube (10), an upper joint (20) sleeved on the upper part of the central tube (10), a de-sealing sleeve (30) located on the outer periphery of the central tube (10) and the upper joint (20), and a balancing piston (40) located between the central tube (10) and the de-sealing sleeve (30); The upper joint (20) and the unsealing sleeve (30) are connected via unsealing shear pins (50); The lower part of the unsealing sleeve (30) is provided with an extension section (31), a gap is provided between the extension section (31) and the central tube (10), the balancing piston (40) is located in the gap between the extension section (31) and the central tube (10), and its radial movement is limited by a limiting mechanism; It also includes a locking sleeve (80) disposed in a gap formed by the extending section (31) and the central tube (10), wherein the lower portion of the extending section (31) is connected to the locking sleeve (80) via bolts; The locking sleeve (80) is in a locked state with the central tube (10) through a locking mechanism. as well as, The locking sleeve (80) has an unlocked state in which it is unlocked from the central pipe (10) after the locking mechanism is unlocked; The locking mechanism comprises a locking steel column (90) arranged in a transversely penetrating through groove of the locking sleeve (80) and a locking groove (01) arranged on the outer wall of the central tube (10); After the locking steel column (90) moves laterally to be engaged with the locking groove (01) under the lateral thrust of the balancing piston (40) moving downward, the locking sleeve (80) is in a locked state; After the locking steel column (90) loses the thrust of the balancing piston (40), the locking sleeve (80) is in an unlocked state; The lower part of the balancing piston (40) is provided with an extending section (41), the top of the locking sleeve (80) is provided with a convex section (81), and a gap is provided between the convex section (81) and the unsealing sleeve (30); When the extending section (41) is inserted into the gap between the protruding section (81) and the unsealing sleeve (30), the limiting mechanism limits the radial movement of the balancing piston (40) and has a tendency to drive the balancing piston (40) to move upward; The through slot that transversely passes through the locking sleeve (80) is located in the raised section (81).

2. The self-anchored balanced expansion packer according to claim 1, characterized in that: The limiting mechanism comprises a snap ring (70) located at the top of the raised section (81) and an anti-disc spring (60) located just above the snap ring (70); There is a gap between the anti-disc spring (60) and the unsealing sleeve (30), and the extension section (41) can be inserted into the gap between the anti-disc spring (60) and the unsealing sleeve (30), and under the action of external force, the balance piston (40) compresses the anti-disc spring (60), and at the same time, the extension section (41) of the balance piston (40) is further inserted into the gap between the protruding section (81) and the unsealing sleeve (30).

3. The self-anchored balanced expansion packer according to claim 1, characterized in that: The upper joint (20) and the unsealing sleeve (30) are connected via a step structure, and the unsealing shear pin (50) penetrates the unsealing sleeve (30) and is then connected to the upper joint (20); The central pipe (10) and the upper joint (20) are connected by bolts.

4. The self-anchored balanced expansion packer according to claim 3, characterized in that: It also includes a liquid inlet sealing piston (110), a return spring (120), a connecting sleeve (130), a rubber sleeve upper end joint (140) and a rubber sleeve (150) which are sequentially sleeved on the central tube (10) and located at the lower end of the locking sleeve (80); The liquid inlet sealing piston (110) and the return spring (120) are located in an annulus formed by the central tube (10), the locking sleeve (80) and the connecting sleeve (130); The upper end surface of the liquid inlet sealing piston (110) is in close contact with the lower end surface of the locking sleeve (80), the lower end surface of the liquid inlet sealing piston (110) is in close contact with the upper end surface of the return spring (120), and the lower end surface of the return spring (120) is in close contact with the step surface of the connecting sleeve (130); The central tube (10) is provided with a liquid inlet hole (03), and the liquid inlet hole (03) is in communication with the annular space between the locking sleeve (80) and the central tube (10); The return spring (120) is configured to be in a compressed state and always has a tendency to drive the liquid inlet sealing piston (110) to move upward to close the liquid inlet sealing channel.

5. The self-anchored balanced expansion packer according to claim 4, characterized in that: It also includes a rubber cylinder lower end joint (160), a lower sealing plug (170) and a lower joint (190) arranged at the lower end of the rubber cylinder (150); The lower end surface of the step inside the lower end joint (160) of the rubber sleeve is in close contact with the upper end surface of the lower sealing plug (170); a groove is provided at the lower portion of the lower sealing plug (170) and there is a gap between the lower sealing plug and the center tube (10); a square sealing ring (180) is provided at the bottom of the gap; the center tube (10), the lower sealing plug (170) and the square sealing ring (180) form an oil-filled sealing cavity (02).

6. The self-anchored balanced expansion packer according to claim 5, characterized in that: It also includes a pressure relief groove (04) arranged on the outer wall of the central tube (10), wherein the pressure relief groove (04) is arranged directly below the square sealing ring (180); The outer wall of the central tube (10) between the square sealing ring (180) and the lower joint (190) is coated with a non-metallic coating.

7. A setting system using the self-anchored balanced expandable packer according to any one of claims 1 to 6, characterized in that: The invention comprises a first-stage sliding sleeve (240) arranged at the lower part of a self-anchored balanced expansion packer (260) in a casing (100) and a second-stage sliding sleeve (250) located at the lower part of the first-stage sliding sleeve (240), wherein the inner diameter of the first-stage sliding sleeve (240) is greater than the inner diameter of the second-stage sliding sleeve (250).

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