A hydraulic packer

Abstract

A hydraulic packer, comprising: a central tube, an upper slip assembly, a rubber sleeve assembly, a lower slip assembly and a hydraulic assembly are sequentially arranged from top to bottom outside the central tube; the upper slip assembly and the lower slip assembly are structurally identical, each comprising a slip seat coaxially sleeved on the outer wall of the central tube, a slip pipe sleeved on the outer wall of the slip seat, a plurality of conical bosses arranged on the outer wall of the slip seat, and a plurality of conical holes matched with the conical bosses; the slip pipe is provided with a plurality of split grooves arranged in an array along the circumference at both ends, and the split grooves at both ends are staggered with each other; the rubber sleeve assembly comprises a middle rubber sleeve and end rubber sleeves arranged at both ends of the middle rubber sleeve, a washer with a circular ring structure is arranged between the middle rubber sleeve and the end rubber sleeves, and annular grooves are arranged on the inner walls of the middle rubber sleeve and the middle sections of the end rubber sleeves; the hydraulic assembly is provided with at least two groups, and a thrust sleeve is sleeved outside the central tube between the uppermost hydraulic assembly and the lower slip assembly. The scheme has better seat hanging stability and sealing performance, and can effectively prevent the slip from loosening and falling off.

Description

Technical Field

[0001] This invention belongs to the field of oil and gas well drilling tool technology, and particularly relates to a hydraulic packer. Background Technology

[0002] In oilfield well completion and fracturing operations, it is often necessary to perform segmented fracturing operations on different sections of the wellbore in vertical, directional, or horizontal wells. During segmented fracturing, packers are required to achieve inter-section isolation. Existing packers are typically hydraulically driven, using surface pressure to move a hydraulic piston. As the piston moves, it first pushes the slips axially while simultaneously expanding outwards, causing the teeth on the outer side of the slips to engage with the casing, thus achieving mounting. At the same time, the casing is also subjected to axial pressure and then expands outwards to achieve a seal.

[0003] The following problems still exist in the use of existing packers and urgently need to be solved:

[0004] First, after the existing slips expand, they will form independent individual slips. Because the well is constantly subjected to vertical impacts, some slips are prone to loosening or even falling off. Once one slip becomes loose, the circumferential force on which the seat hanger relies will be destroyed, causing the seat cover to fail and the packer to fall off.

[0005] Secondly, although the existing technology has a sealing structure with multiple rubber tubes, the rubber tubes are usually simple cylindrical structures. Although multiple rubber tubes can extend the sealing surface of the rubber tubes, when the two ends of the rubber tubes are subjected to force, the position of the outward expansion section is uncontrollable. It is impossible to make the rubber tubes expand outward accurately at the same cross section, making it difficult to form a closed annular sealing structure, thereby reducing the sealing effect and pressure bearing capacity. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a hydraulic packer with better mounting stability and sealing performance, effectively preventing the slips from loosening and falling off.

[0007] In order to achieve the objective of this invention, the following solution is proposed:

[0008] A hydraulic packer includes: an upper slip assembly, a rubber sleeve assembly, a lower slip assembly, and a hydraulic assembly arranged sequentially from top to bottom outside a central tube;

[0009] The upper and lower clamping components have the same structure, both including a clamping seat coaxially sleeved on the outer wall of the central tube, a clamping tube sleeved on the outer wall of the clamping seat, and multiple conical bosses on the outer wall of the clamping seat. The clamping tube has conical holes that match the conical bosses one by one. The large ends of the conical holes of the two clamping tubes face the rubber sleeve assembly. The clamping tube of the upper clamping component is fixed on the central tube. Multiple dividing grooves are arranged in a circumferential array at both ends of the clamping tube, and the dividing grooves at both ends are intersected.

[0010] The rubber sleeve assembly includes a middle rubber sleeve and end rubber sleeves located at both ends of the middle rubber sleeve. The outer end face of the end rubber sleeve abuts against the end face of the clamp seat at both ends. A ring-shaped washer is provided between the middle rubber sleeve and the end rubber sleeve. An annular groove is provided on the inner wall of the middle section of the middle rubber sleeve and the end rubber sleeve. The cross-section of the groove is V-shaped, and the included angle of the V-shape faces outward from the circumference.

[0011] The hydraulic assembly has at least two sets. A thrust sleeve is fitted between the uppermost hydraulic assembly and the lower slip assembly on the outside of the central tube. The upper end of the thrust sleeve abuts against the slip tube end face of the lower slip assembly. The hydraulic assembly is used to push the thrust sleeve to move towards the upper end of the central tube. The thrust sleeve is connected to the side wall of the slip seat of the lower slip assembly by a shear pin.

[0012] The beneficial effects of this invention are as follows:

[0013] 1. After the slip tube expands outward to form slips that engage with the sleeve, both ends of the slips remain connected, ensuring that all slips are interconnected and preventing any slip from falling off or loosening. This effectively improves the stability and durability of the mounting.

[0014] 2. When the middle rubber sleeve and the end rubber sleeve are subjected to axial pressure, the annular groove expands outward, which not only quickly forms an annular sealing structure, but also ensures that the formed annular sealing structure is a closed annular structure to ensure the sealing effect. Attached Figure Description

[0015] The accompanying drawings described herein are merely illustrative of selected embodiments, not all possible implementations, and are not intended to limit the scope of the invention.

[0016] Figure 1 A cross-sectional view of the packer of this application is shown.

[0017] Figure 2 It shows Figure 1 A magnified view of a portion of point A in the middle.

[0018] Figure 3 It shows Figure 1 A magnified view of a section at point B.

[0019] Figure 4 It shows Figure 1 A magnified view of a section at point C.

[0020] Figure 5 It shows Figure 1 A magnified view of a section at point D.

[0021] Figure 6 A schematic diagram of the structure of the slip tube of this application is shown.

[0022] Figure 7 A schematic diagram of the internal structure of the piston of this application is shown.

[0023] Figure 8 A cross-sectional view of the preferred piston structure of this application is shown.

[0024] The markings in the diagram are: center tube-1, oil inlet hole-11, upper slip assembly-2, lower slip assembly-4, shear pin-41, shear nail-42, slip seat-21, conical boss-211, slip tube-22, conical hole-221, dividing groove-222, through hole-223, rubber sleeve assembly-3, middle rubber sleeve-31, lip-311, receiving groove-312, end rubber sleeve-32, washer-33, bushing-34, hydraulic assembly-5, sliding sleeve-51, annular chamber-511, hydraulic chamber-512, piston-52, annular groove-521, mounting hole-522, side hole-523, retaining ring-53, thrust sleeve-6, one-way locking ring-7. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the implementation methods of the present invention will be described in detail below with reference to the accompanying drawings. However, the embodiments described in this invention are only some embodiments of the present invention, and not all embodiments.

[0026] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0027] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product is in use, and are only for the convenience of describing the invention and simplifying the description. The terms "first," "second," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance. The terms "parallel," "vertical," etc., do not mean that the components are required to be absolutely parallel or perpendicular, but can be slightly tilted.

[0028] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection, an indirect connection through an intermediate medium, or a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0029] like Figures 1 to 4 As shown, a hydraulic packer is characterized by comprising: an upper slip assembly 2, a rubber sleeve assembly 3, a lower slip assembly 4, and a hydraulic assembly 5 arranged sequentially from top to bottom outside a central tube 1.

[0030] Specifically, such as Figure 1 , Figure 2 and Figure 6 As shown, the upper slip assembly 2 and the lower slip assembly 4 have the same structure, both including a slip seat 21 coaxially sleeved on the outer wall of the central tube 1. A slip tube 22 is sleeved on the outer wall of the slip seat 21. The outer wall of the slip seat 21 is provided with multiple conical bosses 211. The slip tube 22 has conical holes 221 that match the conical bosses 211 one by one. The large ends of the conical holes 221 of the two slip tubes 22 face the rubber sleeve assembly 3. Since the slip assembly 2 and the lower slip assembly 4 are respectively located at both ends of the rubber sleeve assembly 3, the large ends of the corresponding conical holes 221 of the slip assembly 2 and the lower slip assembly 4 are arranged opposite each other. The slip tube 22 of the upper slip assembly 2 is fixed on the central tube 1. Specifically, in this embodiment, the central tube The upper end of 1 is provided with an upper connector, which is connected to the outer wall of the central tube 1 through an internal thread. It is used to restrict the upward movement of the slip tube 22 of the upper slip assembly 2. Multiple dividing grooves 222 are arranged in a circumferential array at both ends of the slip tube 22, and the dividing grooves 222 at both ends are intersected. When the slip seat 21 and the slip tube 22 move relative to each other in the axial direction, the slip tube 22 can be pushed outward by the structure of the conical boss 211 and the conical hole 221. When it expands, the dividing grooves 222 will be opened, so that the adjacent dividing grooves 222 form slip pieces that bite into the sleeve. The two ends of the slip pieces are still connected, so that all the slip pieces are connected to each other, preventing any slip piece from falling off or loosening.

[0031] Specifically, such as Figure 1 , Figure 3As shown, the rubber sleeve assembly 3 includes a middle rubber sleeve 31 and end rubber sleeves 32 located at both ends of the middle rubber sleeve 31. The outer end faces of the end rubber sleeves 32 abut against the end faces of the clamping seats 21 at both ends. The clamping seats 21 at both ends refer to the clamping seats 21 of the upper clamping assembly 2 and the lower clamping assembly 4. A ring-shaped washer 33 is provided between the middle rubber sleeve 31 and the end rubber sleeves 32 to ensure the balance of circumferential force on the adjacent end faces of the middle rubber sleeve 31 and the end rubber sleeves 32, and to avoid the middle rubber sleeve 31 and the end rubber sleeves 32 from being subjected to force. 2. Uneven local force on the circumference leads to uneven outward expansion at different parts of the circumference, reducing the sealing effect; the inner wall of the middle section of the rubber cylinder 31 and the end rubber cylinder 32 is provided with annular grooves, the cross section of which is V-shaped, with the included angle of the V-shape facing outward. When the middle rubber cylinder 31 and the end rubber cylinder 32 are subjected to axial pressure, the annular groove part will expand outward first. This structure can not only quickly form an annular sealing structure, but also ensure that the formed annular sealing structure is a closed annular structure, so as to ensure the sealing effect.

[0032] Specifically, such as Figure 1 , Figure 4 , Figure 5 , Figure 7 and Figure 8 As shown, the hydraulic assembly 5 has at least two sets, including a sliding sleeve 51 coaxially sleeved outside the central tube 1. The inner wall of the sleeve 51 and the outer wall of the central tube 1 have an annular chamber 511. The annular chamber 511 contains a piston 52 with an annular structure. The inner wall of the piston 52 and the outer wall of the central tube 1 are provided with matching annular grooves 521. A retaining ring 53 passes through the annular groove 521. The inner and outer sides of the cross-section of the retaining ring 53 are respectively embedded in the annular grooves 521 on the piston 52 and the central tube 1, for fixing the piston 52 axially on the central tube 1. This mechanism uses the cross-section of the entire retaining ring 53 in the width direction as a shearing surface. Compared with the structure of the positioning pin that uses the axial cross-section as the shearing surface, the shearing surface of this solution is larger, which can effectively prevent the retaining ring 53 from being cut off, and helps to improve the firmness and durability of the axial installation of the piston 52. As a preferred embodiment, the cross-sections of the annular grooves 521 on the piston 52 and the central tube 1 are both semi-circular structures, and the cross-section of the retaining ring 53 is circular. The inner and outer sides of the circle are located in the two semi-circular annular grooves 521 respectively. A hydraulic chamber 512 is formed between the upper end face of the piston 52 and the upper end face of the annular chamber 511. An oil inlet hole 11 communicating with the hydraulic chamber 512 is opened on the side wall of the central tube 1. A thrust sleeve 6 is sleeved between the uppermost hydraulic component 5 and the lower slip component 4 on the outside of the central tube 1. Its upper end abuts against the end face of the slip tube 22 of the lower slip component 4, and its lower end abuts against the end face of the sliding sleeve 51 of the uppermost hydraulic component 5. The thrust sleeve 6 is connected to the side wall of the slip seat 21 of the lower slip component 4 by a shear pin 41.

[0033] The upper end of the central tube 1 is connected to the drill pipe via an upper connector, and the lower end of the central tube 1 is equipped with a lower structure for connecting a ball dropper. During operation, the ball dropper is inserted into the central tube 1 through the drill pipe. When the ball dropper falls into the tapered hole inside the lower connector, it can block the lower end channel of the central tube 1. Then, liquid is injected into the central tube 1 through the drill pipe via the ground hydraulic station. Since the lower end of the central tube 1 is blocked, the liquid will enter the hydraulic chamber 512 through the oil inlet 11. The piston 52 cannot move along the axis of the central tube 1. Therefore, the liquid entering the hydraulic chamber 512 will push the sliding sleeve 51 to move upward, and then push the thrust sleeve 6 to move upward. Multiple hydraulic components 5 work simultaneously, which helps to increase the upward speed of the thrust sleeve 6 and ensures that sufficient hydraulic pressure is generated.

[0034] When the thrust sleeve 6 moves upward, it will push the lower slip assembly 4 to move upward as a whole. The slip seat 21 of the lower slip assembly 4 pushes the rubber sleeve assembly 3 upward to compress it, and the rubber sleeve assembly 3 pushes the slip seat 21 of the upper slip assembly 2 to move upward. During the upward movement of the slip seat 21 of the upper slip assembly 2, the conical boss 211 on its outer wall will push the slip tube 22 to expand outward, dividing the groove 222, so that the slip tube 22 forms multiple slip pieces arranged in a circumferential array. The outer wall of the slip pieces is engaged with the inner wall of the casing in the well to achieve the first stage of mounting. At the same time as the first stage of mounting is implemented, the rubber sleeve assembly 3 is also being gradually compressed, so that the rubber sleeve assembly 3 forms three complete annular sealing structures between the outer wall of the central tube 1 and the inner wall of the casing to achieve preliminary sealing.

[0035] After completing the first stage of mounting and initial sealing, liquid is continued to be added, causing the thrust sleeve 6 to move upwards further, increasing the axial force on the middle rubber sleeve 31 and the end rubber sleeve 32. This increases the outward expansion of the middle rubber sleeve 31 and the end rubber sleeve 32, increasing the width of the annular sealing structure and further improving the sealing performance, thus achieving the final sealing state. When the shear force between the thrust sleeve 6 and the slip seat 21 of the lower slip assembly 4 reaches the set value, the shear pin 41 will be cut off. After the shear pin 41 is cut off... Because the upper end of the slip seat 21 of the lower slip assembly 4 is restricted by the rubber sleeve assembly 3, the slip seat 21 of the lower slip assembly 4 cannot continue to rise. The thrust sleeve 6 will push the slip tube 22 of the lower slip assembly 4 to rise. By utilizing the cooperation between the conical hole 221 and the conical boss 211, the slip tube 22 of the lower slip assembly 4 gradually expands outward during the rising process and forms multiple slip pieces arranged in a circumferential array. The slip pieces of the lower slip assembly 4 are engaged with the sleeve to form the second stage seat.

[0036] This solution not only employs a special slip structure design, ensuring that the slips formed after the slip tube 22 is unfolded remain connected, effectively preventing some slips from loosening or falling off, but also greatly improves the stability and durability of the mounting. By utilizing the upper slip assembly 2 and the lower slip assembly 4, two mounting points are formed at both ends of the rubber sleeve assembly 3, effectively ensuring the stability of the relative position between the rubber sleeve assembly 3 and the sleeve, greatly reducing the eccentricity between the rubber sleeve assembly 3 and the sleeve, thereby ensuring the uniformity of the circumferential force on the rubber sleeve assembly 3 and improving the sealing effect.

[0037] Preferred, such as Figure 6 As shown, the root of each dividing groove 222 has a through hole 223 communicating with it. The inner diameter of the through hole 223 is 3 to 5 times larger than the width of the dividing groove 222, so as to reduce the stress at the root of the dividing groove 222 and avoid the root of the dividing groove 222 from cracking and forming a separate slip.

[0038] Preferred, such as Figure 3 As shown, both the middle rubber cylinder 31 and the end rubber cylinder 32 are provided with bushings 34 that match the shape of the annular groove. The bushings 34 are rigid structures. When the middle rubber cylinder 31 and the end rubber cylinder 32 are subjected to axial compression, the inclined surfaces at both ends of the bushings 34 will cause the middle rubber cylinder 31 and the end rubber cylinder 32 to expand outward from the middle position, so that the middle rubber cylinder 31 and the end rubber cylinder 32 are uniformly compressed towards the middle and expand outward along the cross section of the bushings 34, forming a complete and closed annular seal at the cross section of the bushings 34, thereby ensuring the reliability of the seal.

[0039] Preferred, such as Figure 3 As shown, the outer diameter of the washer 33 is smaller than the outer diameters of the middle rubber cylinder 31 and the end rubber cylinder 32. The opposite ends of the middle rubber cylinder 31 and the end rubber cylinder 32 each have a lip 311 fitted onto the outside of the washer 33. The sum of the lengths of the lips 311 of the middle rubber cylinder 31 and the end rubber cylinder 32 is greater than the length of the washer 33. The reference direction for this length is the axial direction of the central tube 1. The length of the lip 311 refers to the dimension protruding from the corresponding end faces of the middle rubber cylinder 31 and the end rubber cylinder 32. When the middle rubber cylinder 31 and the end rubber cylinder 32 are subjected to axial pressure... The lips 311, which are fitted on both ends of the outer side of the gasket 33, will press towards the middle of the gasket 33 and form an annular protrusion in the middle position of the gasket 33. When the annular protrusion contacts the inner wall of the casing, another sealing structure will be formed. This scheme not only increases the number of sealing structures formed by the rubber sleeve assembly 3, but also effectively seals the contact surfaces between the middle rubber sleeve 31 and the end rubber sleeve 32 and the gasket 33, effectively preventing liquid from entering between the middle rubber sleeve 31 and the end rubber sleeve 32 and the central tube 1, and preventing liquid leakage in the well.

[0040] Further preferred, such as Figure 3As shown, a receiving groove 312 is formed between the end face of the middle rubber tube 31 and the end rubber tube 32 and the inner wall of the corresponding lip 311, which is used to fill the sealing grease. During the compression of the rubber tube assembly 3, the space of the receiving groove 312 will be gradually compressed, and the sealing grease filled inside will be pressed into the contact surface between the middle rubber tube 31 and the end rubber tube 32 and the central tube 1, so as to improve the lubrication of the middle rubber tube 31 and the end rubber tube 32 during the compression process, so that the middle rubber tube 31 and the end rubber tube 32 can be compressed smoothly along the axial direction, thereby making it easier for the middle rubber tube 31 and the end rubber tube 32 to expand outward. In addition, during the compression process in the space of the receiving groove 312, the size of the lip 311 protruding from the end face of the middle rubber tube 31 and the end rubber tube 32 will be further increased, and the lip 311 will also be further compressed, so that the outward expansion of the contacting lips 311 is greater, which helps to further improve the sealing effect of the lip 311.

[0041] Preferred, such as Figure 1 As shown, a one-way locking ring 7 is provided between the thrust sleeve 6 and the central tube 1. A notch is provided on one side of the one-way locking ring 7. The outer side of the one-way locking ring 7 has one-way teeth. The inner wall of the thrust sleeve 6 has a tooth structure that matches the one-way teeth. The inclined surface of the one-way teeth is inclined towards the outer side of the lower end of the central tube 1. The angle between the top surface of the one-way teeth and the axis of the central tube 1 is less than or equal to 90 degrees. During the upward movement of the thrust sleeve 6 relative to the central tube 1, the notch of the one-way locking ring 7 will be compressed, thereby allowing the thrust sleeve 6 to move upward smoothly. The inclined surface of the one-way teeth also helps the thrust sleeve 6 to move towards the upper end of the central tube 1. After the mounting is completed, the top surface of the one-way teeth can be used to restrict the downward movement of the thrust sleeve 6, thereby keeping the slip tube 22 in the mounted state.

[0042] Preferred, such as Figure 2 , Figure 5 As shown, shear pins 42 are connected between the slip seat 21 of the upper slip assembly 2 and the side wall of the central tube 1. The shearing force required by the shear pins 42 is less than that of the shear pins 41. When the packer is not in use, the position of the slip seat 21 on the central tube 1 is kept stable, and the slip seat 21 is prevented from moving during the packer's running-in process, which would cause the slip tube 22 to unfold and thus affect the smooth running-in of the packer.

[0043] Preferred, such as Figure 7 , Figure 8 As shown, the outer wall of the piston 52 has a mounting hole 522, which is tangent to the annular groove 521 on the piston 52. The retaining ring 53 is made of a metal strip, which passes through the mounting hole 522 into the paired annular grooves 521 on the piston 52 and the central tube 1. The shape of the annular groove 521 is used to form the retaining ring 53 structure. This structure not only facilitates the installation of the retaining ring 53, but also completely hides the retaining ring 53 inside the piston 52, which can effectively prevent the retaining ring 53 from falling off.

[0044] Further preferred, such as Figure 8 As shown, a side hole 523 is provided on the inner wall of the annular groove 521 corresponding to the piston 52. The side hole 523 is located at the connection between the mounting hole 522 and the annular groove 521, and is on the extension trajectory of the mounting hole 522. After the metal strip is inserted into the annular groove 521, the end of the metal strip is located in the side hole 523. The side hole 523 can be used to block the end of the metal strip to prevent the metal strip from falling out.

[0045] The above description is merely a preferred embodiment of the present invention and is not intended to be the only or limiting of the invention. Those skilled in the art should understand that various changes or equivalent substitutions made to the present invention without departing from its scope are all within the protection scope of the present invention.

Claims

1. A hydraulic packer, characterized in that, include: The outer side of the central tube (1) is provided with an upper slip assembly (2), a rubber sleeve assembly (3), a lower slip assembly (4), and a hydraulic assembly (5) from top to bottom. The upper clamping assembly (2) and the lower clamping assembly (4) have the same structure, both including a clamping seat (21) coaxially sleeved on the outer wall of the central tube (1), a clamping tube (22) sleeved on the outer wall of the clamping seat (21), and multiple conical bosses (211) on the outer wall of the clamping seat (21). The clamping tube (22) has conical holes (221) that match the conical bosses (211) one by one. The large ends of the conical holes (221) of the two clamping tubes (22) face the rubber sleeve assembly (3). The clamping tube (22) of the upper clamping assembly (2) is fixed on the central tube (1). Multiple dividing grooves (222) are arranged along the circumference at both ends of the clamping tube (22), and the dividing grooves (222) at both ends are intersected. The rubber tube assembly (3) includes a middle rubber tube (31) and end rubber tubes (32) located at both ends of the middle rubber tube (31). The outer end face of the end rubber tube (32) abuts against the end face of the clamp seat (21) at both ends. A ring-shaped washer (33) is provided between the middle rubber tube (31) and the end rubber tube (32). The inner wall of the middle section of the middle rubber tube (31) and the end rubber tube (32) is provided with an annular groove with a V-shaped cross section. The included angle of the V-shape faces outward from the circumference. The hydraulic assembly (5) is provided with at least two sets. A thrust sleeve (6) is provided between the uppermost hydraulic assembly (5) and the lower slip assembly (4) on the outside of the central tube (1). Its upper end abuts against the end face of the slip tube (22) of the lower slip assembly (4). The hydraulic assembly (5) is used to push the thrust sleeve (6) to move towards the upper end of the central tube (1). The thrust sleeve (6) is connected to the side wall of the slip seat (21) of the lower slip assembly (4) through a shear pin (41). The hydraulic assembly (5) includes a sliding sleeve (51) coaxially sleeved outside the central tube (1), with an annular chamber (511) between its inner wall and the outer wall of the central tube (1). A piston (52) with an annular structure is provided in the annular chamber (511). A hydraulic chamber (512) is formed between the upper end face of the piston (52) and the upper end face of the annular chamber (511). An oil inlet hole (11) communicating with the hydraulic chamber (512) is opened on the side wall of the central tube (1). The lower end of the thrust sleeve (6) abuts against the end face of the sliding sleeve (51) of the uppermost hydraulic assembly (5). The inner wall of the piston (52) and the outer wall of the central tube (1) are provided with matching annular grooves (521). A retaining ring (53) is inserted in the annular groove (521). The inner and outer sides of the retaining ring (53) are respectively embedded in the annular grooves (521) on the piston (52) and the central tube (1).

2. A hydraulic packer according to claim 1, characterized in that, Both the middle rubber tube (31) and the end rubber tube (32) are provided with bushings (34) that match the shape of the annular groove. The bushings (34) are rigid structures.

3. A hydraulic packer according to claim 1, characterized in that, The outer diameter of the washer (33) is smaller than the outer diameter of the middle rubber cylinder (31) and the end rubber cylinder (32). The middle rubber cylinder (31) and the end rubber cylinder (32) each have a lip (311) fitted on the outside of the washer (33) at one end. The sum of the lengths of the lips (311) of the middle rubber cylinder (31) and the end rubber cylinder (32) is greater than the length of the washer (33).

4. A hydraulic packer according to claim 3, characterized in that, A receiving groove (312) is formed between the end face of the middle rubber tube (31) and the end rubber tube (32) and the inner wall of the corresponding lip (311) for filling with sealant.

5. A hydraulic packer according to claim 1, characterized in that, A one-way locking ring (7) is provided between the thrust sleeve (6) and the central tube (1), with a notch on one side. The outer side of the one-way locking ring (7) has one-way teeth, and the inner wall of the thrust sleeve (6) has a tooth structure that matches the one-way teeth. The inclined surface of the one-way teeth is tilted towards the outer side of the lower end of the central tube (1), and the angle between the top surface of the one-way teeth and the axis of the central tube (1) is less than or equal to 90 degrees.

6. A hydraulic packer according to claim 1, characterized in that, Shear pins (42) are connected between the slip seat (21) of the upper slip assembly (2) and the side wall of the central tube (1). The shearing force required by the shear pins (42) is less than that of the shear pins (41).

7. A hydraulic packer according to claim 1, characterized in that, The piston (52) has an installation hole (522) on its outer side wall. The installation hole (522) is tangent to the annular groove (521) on the piston (52). The retaining ring (53) is made of metal strip.

8. A hydraulic packer according to claim 7, characterized in that, The inner wall of the annular groove (521) corresponding to the piston (52) is provided with a side hole (523). The side hole (523) is located at the connection between the mounting hole (522) and the annular groove (521), and is on the extension trajectory of the mounting hole (522). After the metal strip is inserted into the annular groove (521), the end of the metal strip is located in the side hole (523).

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