Self-setting packer and using method

Abstract

The invention discloses a self-setting packer and a using method, and belongs to the technical field of packers.The self-setting packer comprises a base body unit, a setting unit and a control unit; the base body unit is sleeved with the setting unit and the control unit, and the control unit is located on one side of the setting unit. The control unit is connected with the setting unit; a negative pressure cavity is formed between the setting unit and the base body unit; a closed cavity is formed among the base body unit, the setting unit and the control unit. A dissoluble material is arranged in the control unit; and one end of the dissoluble material is communicated with the closed cavity. According to the self-setting packer disclosed by the invention, the rubber sleeve is compressed by virtue of hydrostatic pressure of a shaft, so that an oil sleeve annulus is sealed, two-way pressure can be borne, and meanwhile, the packer can be unsealed; the device has the advantages of simple structure, no need of manual control, no need of external power, self-setting and the like.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of packers, and particularly relates to a self-setting packer and a use method. BACKGROUND

[0002] In the process of oilfield development, separate layer water injection and separate layer oil production are needed. In the separate layer water injection and separate layer oil production process, packers are needed to separate different reservoirs. At the same time, according to the requirements of the separate layer water injection and separate layer oil production process, a production string is lowered between the separated reservoirs, different downhole tools are configured, and a production string meeting different processes is formed. However, for some special production processes, due to the complexity of the process, the conventional packer cannot meet the setting requirements of the downhole packer, so that some special processes cannot be implemented, which seriously affects the development effect of oilfield development and the recovery rate of the oilfield.

[0003] The downhole packer is a tool for separating different layers and sealing the annular space of the oil pipe and the casing in the oil and gas well, and is widely used in separate layer water injection, separate layer oil production, water finding and water plugging, acidification and fracturing operations.

[0004] At present, the conventional compression type packer mainly has mechanical type and hydraulic type. The mechanical type packer is set by lifting, lowering or rotating the pipe string to complete the setting of the packer. The hydraulic type packer is set by pumping hydraulic pressure from the ground wellhead to complete the setting of the packer. However, in some special process environments, both types of packers cannot be used, for example, separate layer oil production process connected with downhole pumping equipment, separate layer water injection process connected with downhole bridge tool, etc.

[0005] Among the existing types of packers, there is another type of packer called self-sealing packer. This type of packer relies on the interference contact between the outer diameter of the sealing part and the inner diameter of the casing and the working pressure difference to achieve sealing. After the self-sealing packer is lowered into the well, the small interference between the rubber bowl and the inner diameter of the casing makes the rubber bowl moderately adhere to the inner wall of the casing, separating the annular space at the upper and lower ends of the packer. When the pressure at the open end of the rubber bowl is greater than that at the other end, the pressure difference will make the rubber bowl further open and adhere more tightly to the inner wall of the casing, thereby achieving sealing and achieving the purpose of sealing the annulus. However, when there is a pressure difference between the two ends of the packer in the opposite direction, the rubber bowl will be forced to contract, and the upper and lower ends of the packer will be connected to each other. Therefore, this type of packer can only withstand unidirectional pressure, that is, unidirectional sealing.

[0006] Among the existing types of packers, there is also a type called self-expanding packers. These packers utilize an expansion element that automatically expands under the pressure of the downhole liquid to achieve a seal. The core component of a self-expanding packer is an expansion rubber sleeve, typically made of water-swellable or oil-swellable rubber. Once the packer is lowered into the wellbore, the rubber sleeve comes into contact with the liquid (such as water or oil) within the wellbore. Liquid molecules enter the rubber through physical processes such as capillary diffusion and surface adsorption. As the rubber absorbs the liquid molecules, its molecular structure undergoes elastic deformation, gradually expanding in volume. When the resistance to deformation and the osmotic pressure of the liquid reach a relative equilibrium, the expansion reaches a stable state, thus achieving a seal. However, the expansion rate and expansion ratio of the rubber cartridge of a self-expanding packer may be affected by the downhole environment (such as temperature, pressure, and fluid composition), resulting in less-than-expected expansion performance. Furthermore, due to long-term exposure of the expansion material to the complex downhole environment, it may lose its elasticity due to aging, chemical corrosion, or mechanical wear, resulting in a decrease in sealing performance. Furthermore, due to the irreversibility of the expansion material, once the packer expands, it cannot be released. Therefore, this type of packer is generally only used in auxiliary cementing processes.

[0007] After investigation, it was found that the existing technology has the following problems: 1) Existing packers require external power to set the packer. For example, mechanical packers require lifting, lowering, or rotating the tubing string to set the packer mechanically. Another example is hydraulic packers, which require hydraulic pressure to be pumped in from the surface wellhead. Conventional packers generally require a certain amount of external power to set the packer. 2) Due to the complexity of oilfield development, in some special processes, it is impossible to lift, lower, rotate the downhole tubing or pump hydraulic pressure through the surface wellhead to complete the setting of the packer; 3) Conventional packer setting requires ground-based power equipment such as pump trucks and operating machines, which increases the cost of downhole process measures.

[0008] Therefore, in order to solve the above problems, a packer capable of automatically setting is needed. Summary of the Invention

[0009] In view of the above problems, the present invention discloses a self-setting packer, comprising: a base unit, a setting unit and a control unit; The setting unit and the control unit are both sleeved on the periphery of the base unit, and the control unit is located on one side of the setting unit; The control unit is connected to the setting unit; A negative pressure chamber is provided between the setting unit and the base unit; A sealed cavity is provided between the base unit, the setting unit and the control unit; The control unit is provided with a dissolvable material; One end of the dissolvable material is in communication with the sealed cavity.

[0010] Further, the setting unit comprises rubber sleeves, stop rings, fixed seals, piston sleeves, pistons and sealing sleeves. A plurality of rubber sleeves are arranged on the periphery of the base unit. The rubber sleeves are provided with stop rings, which are arranged on the periphery of the base unit. The piston sleeves are arranged on the periphery of the base unit and below the rubber sleeves. The fixed seals are arranged on the periphery of the base unit and between the rubber sleeves and the piston sleeves. One end of the piston sleeve is provided with a piston. One end of the sealing sleeve is connected with the piston.

[0011] Further, the base unit comprises upper shoulders, inner core pipes and outer core pipes. The upper shoulders and the outer core pipes are connected and arranged on the periphery of the inner core pipes. The inner core pipes and the upper shoulders are connected through unblocking pins. The outer core pipes are provided with fixed seals. The inner core pipes are provided with liquid inlet holes and grooves on the outer walls of the bottom ends, and the liquid inlet holes are above the grooves. The rubber sleeves are arranged on the periphery of the outer core pipes and between the upper shoulders and the fixed seals. The fixed seals are in sliding connection with the piston sleeves of the pistons. The pistons are arranged on the periphery of the outer core pipes.

[0012] Further, the base unit further comprises tubing buckles and upper joints. The top ends of the inner core pipes are provided with upper joints. The inner walls of the upper joints are provided with tubing buckles.

[0013] Further, the setting unit further comprises sealing rings. The outer walls of the fixed seals are provided with sealing rings.

[0014] Further, a negative pressure cavity is arranged between the outer core pipes, the fixed seals, the piston sleeves and the pistons.

[0015] Further, the control unit comprises locking blocks and support bodies. The dissolvable material is arranged in the support bodies. The support bodies are arranged on the periphery of the inner core pipes and the outer core pipes, and the support bodies are connected with the outer core pipes through the locking blocks. The other end of the sealing sleeve is connected with the support body through a locking mechanism.

[0016] Furthermore, a sealed cavity is provided between the sealing cylinder, the piston, the outer core tube and the support body.

[0017] Furthermore, the other end of the soluble material is communicated with the main channel cavity inside the inner core tube.

[0018] The present invention also discloses a method for using a self-setting packer, which is used for the self-setting packer, comprising: Lower the assembled self-setting packer into the predetermined position in the wellbore; Wait for a preset time, and the soluble material will gradually dissolve under the action of the liquid in the liquid inlet hole; After the soluble material dissolves, the sealed cavity is connected to the liquid inlet hole; the pressure difference between the static liquid column pressure in the wellbore and the pressure in the negative pressure cavity pushes the piston and piston cylinder upward, pushing the retaining ring to compress the rubber cylinder to seal the oil casing annulus, and the packer is set; When the operation is completed, the tubing is lifted up, and under the action of the friction force of the rubber tube and the upward force of the tubing, the unsealing pin is cut off, the inner core tube moves up, the locking block loses its constraint, the support body, sealing tube, piston, and piston cylinder move downward, the rubber tube loses its compression force, returns to its initial state, and the self-sealing packer is unsealed.

[0019] Compared with the prior art, the embodiments of the present invention have at least the following advantages: the self-sealing packer of the present invention relies on the hydrostatic pressure of the wellbore to compress the rubber tube to seal the oil casing annulus, can withstand bidirectional pressure, and can also realize the unsealing of the packer; the present invention has the advantages of simple structure, no need for human control, no need for external power, and self-sealing, which can meet the requirements of complex processes that cannot be sealed by conventional methods, while also reducing construction costs and providing a new process technology for oil field development.

[0020] Other features and advantages of the present invention will be described in the following description, and in part will become apparent from the description, or will be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the embodiments or the description of the prior art. 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 any creative work.

[0022] Figure 1 A structural schematic diagram of a self-setting packer according to an embodiment of the present invention is shown.

[0023] Figure markings: 1. Oil pipe buckle; 2. Upper joint; 3. Unsealing pin; 4. Upper shoulder; 5. Rubber cylinder; 6. Retaining ring; 7. Sealing ring; 8. Fixed seal; 9. Inner core tube; 10. Outer core tube; 11. Negative pressure chamber; 12. Piston cylinder; 13. Main channel chamber; 14. Piston; 15. Sealed chamber; 16. Soluble material; 17. Liquid inlet hole; 18. Locking mechanism; 19. Sealing cylinder; 20. Locking block; 21. Support body; 22. Pin. DETAILED DESCRIPTION

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0025] Figure 1 FIG. 2 shows a schematic structural diagram of a self-setting packer according to an embodiment of the present invention. Figure 1 As shown, a self-setting packer proposed in an embodiment of the present invention includes: a base unit, a setting unit and a control unit; The setting unit and the control unit are both sleeved around the base unit, with the control unit located on one side of the setting unit. For example, the control unit is located below the setting unit. The control unit can be located above the setting unit according to actual conditions.

[0026] The control unit is connected to the setting unit; A negative pressure chamber 11 is provided between the setting unit and the base unit; A sealed chamber 15 is provided between the base unit, the setting unit and the control unit; The control unit is provided with a soluble material 16; One end of the soluble material 16 is communicated with the sealed cavity 15 .

[0027] In some embodiments, the setting unit includes a rubber cylinder 5, a retaining ring 6, a fixed seal 8, a piston cylinder 12, a piston 14 and a sealing cylinder 19; A plurality of the rubber sleeves 5 are sleeved on the periphery of the base unit; A retaining ring 6 is provided between the rubber cylinders 5 and the retaining ring 6 is sleeved on the periphery of the base unit; The piston 14 is sleeved on the periphery of the base unit and is located below the rubber cylinder 5 .

[0028] The fixed seal 8 is arranged on the periphery of the base unit and is located between the rubber cylinder 5 and the piston 14; A piston cylinder 12 is provided at one end of the piston 14; wherein, the piston 14 and the piston cylinder 12 can be designed as two parts, or can be processed into one piece.

[0029] One end of the sealing cylinder 19 is threadedly connected to the piston 14 ; the sealing cylinder 19 is sleeved on the periphery of the piston 14 .

[0030] The self-setting packer of the present invention can separate the wellbore space, and the setting of the packer can be completed without manual operation on the ground; secondly, the packer can be used in processes such as stratified water injection, stratified oil production and stratified measures.

[0031] The retaining ring 6 is sleeved on the periphery of the outer core tube 10 of the base unit. The retaining ring 6 at the bottom abuts against the top of the piston cylinder 12 and the fixed seal 8.

[0032] The retaining ring 6 is placed between the rubber tubes 5 to isolate the rubber tubes 5. The retaining ring 6 is provided to supplement and protect the rubber tubes 5 according to the performance of the rubber tubes 5 and may not be provided if the rubber tubes 5 can meet the requirements of sealing deformation.

[0033] In some embodiments, the base unit includes an upper shoulder 4, an inner core tube 9, and an outer core tube 10; The upper shoulder 4 is connected to the outer core tube 10 and is sleeved on the outer periphery of the inner core tube 9; illustratively, the upper shoulder 4 is connected to the outer core tube 10 by a threaded connection, and is installed on the outer side of the inner core tube 9 after the connection, and is slidably connected.

[0034] The inner core tube 9 and the upper shoulder 4 are connected by an unsealing pin 3; A fixed seal 8 is provided on the outer wall of the outer core tube 10 ; the fixed seal 8 is tubular as a whole; illustratively, the fixed seal 8 is threadedly and sealedly connected to the outer core tube 10 .

[0035] The outer wall of the bottom end of the inner core tube 9 is provided with a liquid inlet hole 17 and a groove; the liquid inlet hole 17 is located above the groove; the liquid inlet hole 17 is connected to the main channel cavity 13 of the production tubing string.

[0036] The rubber sleeve 5 is sleeved on the outer periphery of the outer core tube 10 and is arranged between the upper shoulder 4 and the fixed seal 8; The fixed seal 8 is in sliding connection with the piston cylinder 12 of the piston 14; The piston 14 is sleeved on the outer periphery of the outer core tube 10 .

[0037] The upper shoulder 4 contacts the upper end of the rubber cylinder 5 and supports the rubber cylinder 5 .

[0038] The liquid inlet hole 17 is not limited to being communicated with the main channel cavity 13 of the production string, but may also be communicated with the outer casing annulus of the self-setting packer.

[0039] In some embodiments, the base unit further includes an oil pipe buckle 1 and an upper joint 2; The top of the inner core tube 9 is provided with an upper joint 2; the upper joint 2 and the inner core tube 9 are integrally formed and can also be connected by threaded sealing; The inner wall of the upper joint 2 is provided with an oil pipe buckle 1. The lower end of the upper joint 2 abuts against the upper shoulder 4; The tubing buckle 1 is connected to the lower end of the production tubing string.

[0040] In some embodiments, the setting unit further includes a sealing ring 7; A sealing ring 7 is provided on the outer wall of the fixed seal 8 , and the sealing ring 7 is located between the fixed seal 8 and the piston cylinder 12 .

[0041] The sealing ring 7 is used to seal the movable connections between the negative pressure chamber 11 and the sealed chamber 15 .

[0042] In some embodiments, a negative pressure chamber 11 is provided between the outer core tube 10 , the fixed seal 8 , the piston cylinder 12 and the piston 14 .

[0043] In some embodiments, the control unit includes a locking block 20 and a support body 21; The dissolvable material 16 is disposed in the support 21; The support body 21 is sleeved on the periphery of the inner core tube 9 and the outer core tube 10, and the support body 21 is connected to the outer core tube 10 through the locking block 20; a locking block groove for accommodating the locking block 20 is provided at the bottom of the outer core tube 10; The other end of the sealing cylinder 19 is connected to the support body 21 through a locking mechanism 18. The sealing cylinder 19 is sleeved on the support body 21 and the periphery of the piston 14.

[0044] The lower end of the support body 21 is connected to the oil pipe below it.

[0045] A spiral locking triangular thread is machined on the outer surface of the support body 21, and the triangular thread cooperates with the thread on the locking mechanism 18; A spiral locking small triangular thread is processed on the inner side of the sealing cylinder 19, and the small triangular thread matches the thread on the locking mechanism 18; the sealing cylinder 19 is connected to the support body 21 through the locking mechanism 18.

[0046] In some embodiments, a sealed cavity 15 is provided between the sealing cylinder 19 , the piston 14 , the outer core tube 10 and the support body 21 .

[0047] In some embodiments, one end of the soluble material 16 is connected to the closed cavity 15 , and the other end is connected to the main channel cavity 13 inside the inner core tube 9 through the through hole of the outer core tube 10 and the liquid inlet hole 17 of the inner core tube 9 .

[0048] The soluble material 16 is used to seal the sealed cavity 15. The soluble material 16 is a composite material that can be dissolved by the liquid in the wellbore.

[0049] A pin 22 is provided at the bottom of the support body 21 to prevent the support body 21 from being completely separated from the packer after the packer is unsealed.

[0050] The soluble material 16 is not limited to being disposed in the support body 21 , but may be disposed at any position of the sealed cavity 15 that can be fixed and communicated with the liquid inlet 17 .

[0051] The soluble material 16 is a composite material (metal or other) that can chemically react with underground mineral water. The dissolution time is related to the ratio and structure of the composite material.

[0052] The self-sealing packer of the present invention relies on the hydrostatic pressure of the wellbore to compress the rubber sleeve 5 to seal the oil casing annulus, can withstand bidirectional pressure, and can also realize the unsealing of the packer; the present invention has the advantages of simple structure, no need for human control, no need for external power, and self-sealing, which can meet the requirements of complex processes that cannot be set by conventional methods, and also reduces construction operation costs, providing a new process technology means for oil field development.

[0053] A method for using a self-setting packer comprises running the self-setting packer, setting the self-setting packer and unsealing and removing the self-setting packer.

[0054] A method for using a self-setting packer, the specific steps are as follows: Step 1: Follow Figure 1 The assembly shown is an upper connector 2, an unsealing pin 3, an upper shoulder 4, a rubber sleeve 5, a retaining ring 6, a sealing ring 7, a fixed seal 8, an inner core tube 9, an outer core tube 10, a piston cylinder 12, a piston 14, a dissolvable material 16, a locking mechanism 18, a sealing cylinder 19, a locking block 20, a support body 21, and a pin 22; Step 2: Lower the assembled self-setting packer into the predetermined position in the wellbore; Step 3: Wait for a preset time, during which the soluble material 16 gradually dissolves under the action of the liquid in the liquid inlet 17; Step 4: Setting the Self-Setting Packer: After the soluble material 16 dissolves, the sealed chamber 15 communicates with the fluid inlet 17. The differential pressure between the wellbore hydrostatic column and the pressure within the negative pressure chamber 11 pushes the piston 14 and piston cylinder 12 upward, pushing the retaining ring 6 to compress the rubber sleeve 5 to seal the casing annulus, and the packer is set. Simultaneously, the locking mechanism 18 locks the sealing sleeve 19 to the support 21, preventing the rubber sleeve 5 from elastically recovering. For example, the locking mechanism 18 is composed of two sets of reverse triangular threads, one set is a large triangular thread and the other set is a small triangular thread. When the sealing cylinder 19 moves upward, the small triangular thread is in the forward direction and the large triangular thread is in the reverse direction. Since the gap of the locking mechanism 18 can meet the forward climbing gap of the small triangular thread, the sealing cylinder 19 can move upward across the gap of the small triangular thread. Conversely, when the sealing cylinder 19 moves downward, the small triangular thread is in the reverse direction and the large triangular thread is in the forward direction. Since the gap of the locking mechanism 18 cannot meet the forward climbing gap of the large triangular thread, the locking mechanism 18 locks the sealing cylinder 19 on the support body 21.

[0055] Step 5: Unsealing and removing the self-setting packer: When the operation is completed, lift the tubing string. Under the action of the friction force of the rubber cylinder 5 and the upward lifting force of the tubing string, the unsealing pin 3 is cut off, the inner core tube 9 moves upward, the locking block 20 loses its constraint, the support body 21, the sealing cylinder 19, the piston 14, and the piston cylinder 12 move downward, the rubber cylinder 5 loses its compression force, the rubber cylinder 5 returns to its initial state, and the self-setting packer is unsealed.

[0056] There is a groove at the lower end of the inner core tube 9. When the inner core tube 9 moves upward, the locking block 20 supported on the outside of the inner core tube 9 will fall into the groove of the inner core tube 9. The locking block 20 loses its constraint, and the support body 21 will break away from the constraint of the inner core tube 9 and move downward.

[0057] 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 make equivalent replacements for some of the technical features therein; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A self-setting packer, characterized in that: include: Base unit, setting unit and control unit; The setting unit and the control unit are both sleeved on the periphery of the base unit, and the control unit is located on one side of the setting unit; The control unit is connected to the setting unit; A negative pressure chamber (11) is provided between the setting unit and the base unit; A sealed cavity (15) is provided between the base unit, the setting unit and the control unit; A dissolvable material (16) is provided in the control unit; One end of the soluble material (16) is in communication with the sealed cavity (15).

2. The self-setting packer according to claim 1, characterized in that: The setting seal unit comprises a rubber cylinder (5), a retaining ring (6), a fixed seal (8), a piston cylinder (12), a piston (14) and a sealing cylinder (19); A plurality of rubber cylinders (5) are sleeved on the periphery of the base unit; A retaining ring (6) is provided between the rubber cylinders (5), and the retaining ring (6) is sleeved on the periphery of the base unit; The piston (14) is sleeved on the periphery of the base unit and is located below the rubber cylinder (5); The fixed seal (8) is arranged on the periphery of the base unit and is located between the rubber cylinder (5) and the piston (14); A piston cylinder (12) is provided at one end of the piston (14); One end of the sealing cylinder (19) is connected to the piston (14).

3. The self-setting packer according to claim 2, characterized in that: The base unit comprises an upper shoulder (4), an inner core tube (9) and an outer core tube (10); The upper shoulder (4) is connected to the outer core tube (10), and both are sleeved on the outer periphery of the inner core tube (9); The inner core tube (9) and the upper shoulder (4) are connected via an unsealing pin (3); The outer core tube (10) is provided with a fixed seal (8); A liquid inlet hole (17) and a groove are provided on the outer wall of the bottom end of the inner core tube (9), and the liquid inlet hole (17) is located above the groove; The rubber sleeve (5) is sleeved on the outer periphery of the outer core tube (10) and is arranged between the upper shoulder (4) and the fixed seal (8); The fixed seal (8) is slidably connected to the piston cylinder (12) of the piston (14); The piston (14) is sleeved on the periphery of the outer core tube (10).

4. The self-setting packer according to claim 3, characterized in that: The base unit also includes an oil pipe buckle (1) and an upper joint (2); The top end of the inner core tube (9) is provided with an upper joint (2); An oil pipe buckle (1) is provided on the inner wall of the upper joint (2).

5. The self-setting packer according to claim 3, characterized in that: The setting unit further includes a sealing ring (7); A sealing ring (7) is provided on the outer wall of the fixed seal (8).

6. The self-setting packer according to claim 3, characterized in that: A negative pressure chamber (11) is provided between the outer core tube (10), the fixed seal (8), the piston cylinder (12) and the piston (14).

7. The self-setting packer according to claim 3, characterized in that: The control unit comprises a locking block (20) and a support body (21); The soluble material (16) is disposed in the support body (21); The support body (21) is sleeved on the periphery of the inner core tube (9) and the outer core tube (10), and the support body (21) is connected to the outer core tube (10) via a locking block (20); The other end of the sealing cylinder (19) is connected to the support body (21) via a locking mechanism (18).

8. The self-setting packer according to claim 7, characterized in that: A sealed cavity (15) is provided between the sealing cylinder (19), the piston (14), the outer core tube (10) and the support body (21).

9. The self-setting packer according to claim 8, characterized in that: The other end of the soluble material (16) is in communication with the main channel cavity (13) inside the inner core tube (9).

10. A method for using a self-setting packer, used for the self-setting packer according to any one of claims 1 to 9, characterized in that: include: Lower the assembled self-setting packer into the predetermined position in the wellbore; After waiting for a predetermined time, the soluble material (16) gradually dissolves under the action of the liquid in the liquid inlet hole (17); After the soluble material (16) dissolves, the sealed cavity (15) is connected to the liquid inlet hole (17); under the pressure difference between the static liquid column pressure in the wellbore and the pressure in the negative pressure cavity (11), the piston (14) and the piston cylinder (12) are pushed upward, pushing the retaining ring (6) to compress the rubber cylinder (5) to seal the oil casing annulus, and the packer is set; When the operation is completed, the pipe string is lifted up, and under the action of the friction force of the rubber cylinder (5) and the lifting force of the pipe string, the unsealing pin (3) is cut off, the inner core tube (9) moves up, the locking block (20) loses its constraint, the support body (21), the sealing cylinder (19), the piston (14), and the piston cylinder (12) move downward, the rubber cylinder (5) loses its compression force, returns to its initial state, and the self-sealing packer is unsealed.

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