Slip assembly facilitating casing milling and packer

Abstract

The utility model discloses a slip assembly and a packer convenient to implement casing milling, and relates to the technical field of oil field equipment, the packer comprises the slip assembly, the slip assembly comprises a slip bowl and a plurality of slips, each slip is installed on the slip bowl through a clamping groove in the upper end of the slip bowl, and the slip bowl is provided with a plurality of clamping grooves in the upper end of the slip bowl. The clamping device further comprises a clamping spring wrapping the slips, the clamping spring is of a coil-shaped structure formed by winding wires or bars, the two ends of the coil-shaped structure are open, clamping spring grooves penetrating through the two sides of the slips are formed in the outer side faces of the slips, and the clamping spring penetrates through the clamping spring grooves of the slips and makes contact with the bottoms of the clamping spring grooves. The design of the slip assembly has the characteristic that milling is convenient to implement.

Description

Technical Field

[0001] The utility model relates to the technical field of oil field equipment, in particular to a slip assembly and a packer which are convenient for sleeve milling. Background Art

[0002] The packer is a downhole tool used in oil fields in the field of oil production. The Y211 packer is connected to the setting tool when in use. The specific method of use is to lower the packer into the casing to the specified position, lift the pipe string, move the center pipe upward, and the track pin enters the reversing mechanism from the short track. The pipe string is lowered, and the track pin enters the long track from the reversing mechanism to achieve track conversion. Then, the pipe string is slowly lowered, and the top sleeve on the straightening body enters the anchoring body part, and the cover ring of the lock ball is opened to unlock the lock ball; continue to lower the pipe string, the cone moves down, the slip is stretched and stuck on the casing to achieve anchoring; then lower the pipe string, use the slip as the support point to compress the seal, so that it expands and expands, and the side annular space of the seal is sealed. When unsealing the packer, lift the pipe string, the center pipe drives the seal body and the cone to move upward, and the seal and slip are retracted; at the same time, the lock ball, cover ring, top sleeve and other components are restored to their original positions to achieve unsealing. The Y211 packer is a multi-purpose, retrievable, compression packer widely used in oil production, water injection, testing and stimulation operations.

[0003] In order to solve the problem that the packer may not be released normally during use, there are packer milling tools and packers that can be milled in the prior art. Specific technical solutions include the technical solutions provided by patent applications No. CN 200420030728.0 and CN201921919231.7 and the technical solution provided by patent application No. CN201420038614.4. The implementation of these technologies can realize the release and unblocking of the packer by post-milling, and at the same time has the characteristics of shortening the milling time and greatly improving the efficiency of deep well and complex well drilling and production development operations.

[0004] In view of the problem that the packer cannot be released normally, it is necessary to further optimize the structure of the packer. Utility Model Content

[0005] In order to further optimize the structure of the packer proposed above, the utility model provides a slip assembly and a packer that are convenient for casing milling. The packer includes the slip assembly, and the design of the slip assembly is convenient for casing milling.

[0006] In view of the above problems, the utility model provides a cava assembly and a packer that are convenient for implementing casing milling to solve the problems through the following technical points: a cava assembly that is convenient for implementing casing milling, comprising a cava seat and a cava, wherein there are multiple cava, each cava is installed on the cava seat through a slot at the upper end of the cava seat, and also includes a retaining spring wrapped around the cava, wherein the retaining spring is a coil-like structure wound by wire or rod, and both ends of the coil-like structure are open, and a retaining spring groove that passes through both sides of the cava is provided on the outer side surface of each cava, and the retaining spring passes through the retaining spring groove of each cava and contacts with the bottom of the retaining spring groove.

[0007] In the prior art, taking the Y211 packer as an example, its main structure includes a liner, a slip assembly, a sealing assembly, and a setting and unsealing assembly, etc., wherein the slip assembly includes a slip and a vertebral body, and the slip is deformed under the extrusion of the vertebral body and is pressed against the inner wall of the casing to achieve anchoring on the casing. The split slip is a conventional form of the slip assembly, specifically, a plurality of slips are arranged at intervals along the circumferential direction of the cylindrical slip seat, the tail end of the slip is movably connected to the slip seat through the slot at the top of the slip seat, and the slip is constrained in the radial direction of the slip seat by the retaining spring wrapped around the outside of the slip. In the prior art, the retaining spring is mostly a coil spring wrapped around the slip, and the coil spring is connected end to end to form a closed ring. When the slip is not opened by the vertebral body, the radial restraining force provided by the retaining spring to the outside of the slip constrains the upper end of the slip to be close to each other. When the slip is opened by the vertebral body, the coil spring undergoes elastic deformation adapted to the amount of slip opening and is accompanied by an increase in the turn pitch.

[0008] For the packers that cannot be unsealed or unstuck normally, the milling unsealing solution is different from the traditional solution. Specifically, when the packer cannot be unsealed or unstuck by lifting, the millable parts on the packer can be milled off, and then the remaining parts can be lifted out to complete the unstuck operation. This can effectively avoid the maintenance costs caused by the overhaul operation and has the characteristics of high operating efficiency. At the same time, for the packer with a cava assembly, the cava on the cava assembly is also a milling object. When the lower end of the milling cylinder acts on the coil spring, the coil spring located on the outer periphery of the cava will produce pulling deformation due to the traction of the rotation of the milling cylinder, and will produce elastic deformation along the axis of the cava seat due to the extrusion of the milling cylinder. Therefore, in the process of milling the retaining spring, the retaining spring has an unstable impact on the milling cylinder, which has an adverse effect on the stability of the rotation of the milling cylinder.

[0009] In the present solution, the retaining spring is a coil-like structure wound by wire or rod. During the process of milling and unsealing the packer, when the upper end of the milling barrel acts on the retaining spring, since the retaining spring only has a bending deformation in the circumferential direction of the cava assembly and the lower end is supported on the side surface of the bottom side of the retaining spring groove, the friction and extrusion of the milling barrel will not cause the retaining spring to produce pulling deformation and elastic deformation along the axial direction of the cava seat, so that the milling barrel is subjected to a stable force during the milling process, so that the milling barrel and the cava assembly can be stably milled. Therefore, the present solution provides a cava assembly with the characteristic of convenient milling.

[0010] It is easy to understand that the two ends of the coil-like structure are open, which means that the two ends of the retaining spring do not have a fixed connection relationship. When the vertebral body acts on the upper end of the cava to open the cava, the compression of the cava on the retaining spring can enable the coil-like structure to be expanded. At this time, the position of the end of the retaining spring is displaced. According to the tightening requirement of the retaining spring on the cava, the retaining spring can be set to a single turn or to multiple turns of more than one turn. In a specific embodiment, the retaining spring is set to be wound with spring steel. The retaining spring made of spring steel only affects a smaller stroke of the milling barrel during the entire milling process. Therefore, although it will increase the difficulty of milling the retaining spring and affect the milling efficiency to a certain extent, if the cava assembly can be unsealed normally, when the vertebral body is lifted, the retaining spring can provide a driving force for the upper end of the cava to move closer, thereby ensuring the smoothness of the unsealing of the packer.

[0011] In a specific embodiment, the slip includes a slip body, the slip body is made of a composite material, and a slip tooth is inlaid on the outer side of the upper end of the slip body. In this solution, the slip tooth can be made of a hard wear-resistant material to ensure the reliability of the slip assembly anchored on the casing. Specifically, the slip tooth is granular and inlaid in a groove on the surface of the slip body. The slip body made of a composite material makes the main part of the slip easy to be milled, further achieving the purpose of facilitating the implementation of milling.

[0012] In a specific embodiment, the tail end of the slip is a T-shaped structure with the maximum width at the lower end of the tail end, each slip is provided with a clamping slot, the clamping slot is a T-shaped slot with the maximum width at the lower end of the clamping slot, the tail end is embedded in the clamping slot, and the lower end of the tail end is embedded in the lower end of the clamping slot, and the width of the lower end of the tail end is greater than the width of the upper end of the clamping slot. In this solution, the tail end of the slip is mounted on the slip seat by using the clamping slot which is a T-shaped slot, and the position of the slip in the circumferential direction and the axial direction of the slip seat can be constrained by using the constraint provided by the clamping slot for the tail end of the slip.

[0013] In a specific embodiment, both sides of the tail end of the slip are provided with inclined surfaces with the slope facing the outside of the slip, and the position where the side wall of the clamping groove acts on the tail end is located on the inclined surface. In this solution, when the slip is deformed under the extrusion of the vertebral body, the inclined surface is the surface that is squeezed during the radial outward movement of the slip. During the radial outward movement of the slip, relative to the sliding of the side wall of the clamping groove and its own deformation, the form of the slip in this solution and the mode of action with the slip seat are beneficial to the slip producing the required radial outward movement.

[0014] In a specific embodiment, for the implementation method in which the tail end is a T-shaped structure and the clamping groove is a T-shaped groove, the inclined surface is located above the maximum width position of the slip, and the side surface of the clamping groove is a slope surface that matches the inclined surface.

[0015] In a specific embodiment, the slips are evenly distributed in a central annular pattern relative to the slip seat. In this solution, the slip assembly and the sleeve can be matched to have a relatively uniform contact and extrusion condition in the circumferential direction.

[0016] In a specific embodiment, the turns on the circlip are stacked along the axial direction of the slip seat. In this solution, under the same number of circlip turns, compared with the case where the turns are stacked along the radial direction of the slip seat, the circlip has a large contact area with the slip, so the initial form of the slip can be better constrained; in addition, when the circlip contacts the sleeve milling cylinder, the sleeve milling cylinder and the circlip have a smaller contact area, which is beneficial to the smooth completion of the circlip sleeve milling.

[0017] The present solution also provides a packer including the slip assembly, and the packer adopts the slip assembly above.

[0018] In a specific embodiment, the packer further includes a sealing assembly disposed above the slip assembly, the sealing assembly including a plurality of rubber tubes, spacer rings disposed between the rubber tubes, an upper pressure cap disposed at the upper end of the rubber tube, and a lower pressure cap disposed at the lower end of the rubber tube, and the spacer rings, the upper pressure cap, and the lower pressure cap are all made of composite materials. In this solution, the spacer rings, the upper pressure cap, and the lower pressure cap, which are parts with larger outer diameters in the axial direction of the packer, are all designed to be made of composite materials. When these parts are stuck on the casing due to reasons such as casing deformation, the packer can be unsealed and unstuck smoothly and efficiently by milling off the composite materials, based on the fact that the upper pressure cap, the spacer ring, and the lower pressure cap are all made of composite materials.

[0019] In a specific embodiment, for a packer with the largest outer diameter of the upper and lower pressure caps, which are both made of composite materials, and the maximum outer diameter is specifically φ115, and the outer diameter of the largest steel body part is φ93.2, when performing the milling and unstuck operation, the inner diameter of the milling barrel used is φ95-100, specifically, an alloy milling barrel with an outer diameter of φ118mm and an inner diameter of φ95mm is used to perform milling operations on the outer composite parts of the packer, ensuring that the packer can be smoothly removed from the well. A packer with related parts made of composite materials can not only ensure the durability of the packer, but also ensure the reliability of the packer. Regarding the installation of the upper pressure cap, lower pressure cap and other parts, in a specific embodiment, the packer includes a center pipe, a joint assembly arranged at the upper end of the center pipe, an upper liner and a lower liner arranged on the outside of the center pipe, and a vertebral body installed at the lower end of the upper liner, the joint assembly includes an upper joint and a middle joint, the upper pressure cap is threadedly connected to the joint assembly, the rubber sleeve and the spacer ring are arranged on the outside of the upper liner, the lower pressure cap is threadedly connected to the vertebral body, and the cava seat is arranged on the lower liner.

[0020] In a specific embodiment, the composite material is a fiber-reinforced epoxy resin composite material. In this solution, a fiber-reinforced epoxy resin composite material is used, which is an existing material, that is, this solution does not involve the improvement of the material. At the same time, the mechanical performance index of the fiber-reinforced epoxy resin composite material is 15-20% higher than that of conventional composite materials, so as to improve the strength and durability of the packer. At the same time, it is a composite material with excellent strength-to-weight ratio and corrosion resistance, which can withstand high pressure and harsh working environment.

[0021] The utility model has the following beneficial effects:

[0022] In the present solution, since the retaining spring only has a bending deformation in the circumferential direction around the cava assembly and the lower end is supported on the side surface of the bottom side of the retaining spring groove, the friction and extrusion of the sleeve milling cylinder will not cause the retaining spring to produce pulling deformation and elastic deformation along the axial direction of the cava seat, so that the sleeve milling cylinder is subjected to a stable force during the sleeve milling process, so that the sleeve milling cava assembly can be carried out stably. Therefore, the present solution provides a cava assembly with the characteristic of convenient sleeve milling. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A half-section diagram of a specific embodiment of the packer described in this solution;

[0024] Figure 2 for Figure 1 A partial enlarged view of part A in the middle.

[0025] The reference numerals in the figure are respectively: 1, upper pressure cap, 2, rubber cylinder, 3, center tube, 4, spacer ring, 5, liner, 6, lower pressure cap, 7, slip teeth, 8, slip, 9, retaining ring, 10, slip seat, 11, retaining groove, 12, tail end, 13, inclined surface, 14, retaining ring groove, 15, lower liner. DETAILED DESCRIPTION

[0026] The present invention is further described in detail below in conjunction with the embodiments, but the present invention is not limited to the following embodiments:

[0027] Embodiment 1:

[0028] like Figure 1 and Figure 2 As shown, a cava assembly that is convenient for implementing sleeve milling includes a cava seat 10 and a cava 8, wherein the number of the cava 8 is multiple, and each cava 8 is installed on the cava seat 10 through a slot 11 at the upper end of the cava seat 10, and also includes a retaining spring 9 wrapped around the cava 8, wherein the retaining spring 9 is a coil-like structure wound by wire or rod, and both ends of the coil-like structure are open, and the outer side surface of each cava 8 is provided with a retaining spring groove 14 that passes through both sides of the cava 8, and the retaining spring 9 passes through the retaining spring groove 14 of each cava 8 and contacts with the bottom of the retaining spring groove 14.

[0029] In the prior art, taking the Y211 packer as an example, its main structure includes a liner, a slip 8 assembly, a sealing assembly, and a setting and unsealing assembly, among which the slip 8 assembly includes a slip 8 and a vertebral body, and the slip 8 is deformed under the extrusion of the vertebral body and is mutually extruded with the inner wall of the casing to achieve anchoring on the casing. The split slip 8 is a conventional form of the slip 8 assembly, specifically, a plurality of slips 8 are arranged at intervals along the circumferential direction of the cylindrical slip seat 10, the tail end 12 of the slip 8 is movably connected to the slip seat 10 through the clamping groove 11 at the top of the slip seat 10, and the slip 8 is constrained in the radial direction of the slip seat 10 by the clamping spring 9 wrapped around the outside of the slip 8. In the prior art, the retaining spring 9 is mostly a coil spring wrapped around the cava 8, and the coil spring is connected end to end to form a closed circular ring. When the cava 8 is not expanded by the vertebral body, the radial constraint force provided by the retaining spring 9 to the outside of the cava 8 constrains the upper ends of the cava 8 to be close to each other. When the cava 8 is expanded by the vertebral body, the coil spring undergoes elastic deformation adapted to the expansion amount of the cava 8 and is accompanied by an increase in the turn pitch.

[0030] For the packers that cannot be unsealed or unstuck normally, the milling unsealing solution is different from the traditional solution. Specifically, when the packer cannot be unsealed or unstuck by lifting, the millable parts on the packer can be milled off, and then the remaining parts can be lifted out to complete the unstuck operation. This can effectively avoid the maintenance costs caused by the overhaul operation and has the characteristics of high operating efficiency. At the same time, for the packer with a cava 8 assembly, the cava 8 on the cava 8 assembly is also a milling object. When the lower end of the milling cylinder acts on the coil spring, the coil spring located on the outer periphery of the cava 8 will produce pulling deformation due to the traction of the rotation of the milling cylinder, and will produce elastic deformation along the axial direction of the cava seat 10 due to the extrusion of the milling cylinder. Therefore, in the process of milling the retaining spring 9, the retaining spring 9 has an unstable impact on the milling cylinder, which has an adverse effect on the stability of the rotation of the milling cylinder.

[0031] In the present solution, the retaining spring 9 is configured as a coil-shaped structure wound by wire or rod. During the process of milling and unsealing the packer, when the upper end of the milling barrel acts on the retaining spring 9, since the retaining spring 9 only has a bending deformation in the circumferential direction of the cava 8 assembly and the lower end is supported on the side surface of the bottom side of the retaining spring groove 14, the friction and extrusion of the milling barrel will not cause the retaining spring 9 to produce pulling deformation and elastic deformation along the axial direction of the cava seat 10, so that the milling barrel is subjected to a stable force during the milling process, so that the milling barrel and the cava 8 assembly can be stably milled. Therefore, the present solution provides a cava 8 assembly with the characteristic of convenient milling.

[0032] It is easy to understand that the two ends of the coil-like structure are open, which means that the two ends of the retaining spring 9 do not have a fixed connection relationship. When the vertebral body acts on the upper end of the cava 8 to open the cava 8, the compression of the cava 8 on the retaining spring 9 can expand the coil-like structure. At this time, the position of the end of the retaining spring 9 is displaced. According to the tightening requirement of the retaining spring 9 on the cava 8, the retaining spring 9 can be set to a single turn or to multiple turns of more than one turn. In a more specific scheme, it is set that the retaining spring 9 is wound with spring steel. The retaining spring 9 made of spring steel only affects a smaller stroke of the milling barrel during the entire milling process. Therefore, although it will increase the difficulty of milling the retaining spring 9 and affect the milling efficiency to a certain extent, if the cava 8 assembly can be unsealed normally, when the vertebral body is lifted, the retaining spring 9 can provide a driving force for the upper end of the cava 8 to move closer, thereby ensuring the smoothness of the unsealing of the packer.

[0033] In a more specific solution, the slip 8 includes a slip 8 body, the slip 8 body is made of a composite material, and the upper outer side of the slip 8 body is inlaid with a slip tooth 7. In this solution, the slip tooth 7 can be made of a hard wear-resistant material to ensure the reliability of the slip 8 assembly anchored on the casing. Specifically, the slip tooth 7 can be in a granular shape and inlaid in a groove on the surface of the slip 8 body. The slip 8 body made of a composite material makes the main part of the slip 8 easy to be milled, further achieving the purpose of convenient milling.

[0034] In a more specific solution, the tail end 12 of the slip 8 is a T-shaped structure with the maximum width position located at the lower end of the tail end 12, and each slip 8 is provided with a clamping slot 11, and the clamping slot 11 is a T-shaped slot with the maximum width position located at the lower end of the clamping slot 11, and the tail end 12 is embedded in the clamping slot 11, and the lower end of the tail end 12 is embedded in the lower end of the clamping slot 11, and the width of the lower end of the tail end 12 is greater than the width of the upper end of the clamping slot 11. In this solution, the tail end 12 of the slip 8 is installed on the slip seat 10 by using the clamping slot 11 which is a T-shaped slot, and the position of the slip 8 in the circumferential direction and the axial direction of the slip seat 10 can be constrained by the clamping slot 11 for the tail end 12 of the slip 8.

[0035] In a more specific solution, both sides of the tail end 12 of the slip 8 are provided with an inclined surface 13 with the slope facing the outside of the slip 8, and the action position of the side wall of the clamping groove 11 on the tail end 12 is located on the inclined surface 13. In this solution, when the slip 8 is deformed under the extrusion of the vertebral body, the inclined surface 13 is the surface that is squeezed during the radial outward movement of the slip 8. During the radial outward movement of the slip 8, relative to the sliding of the side wall of the clamping groove 11 and the deformation of itself, the form of the slip 8 in this solution and the mode of action with the slip seat 10 are beneficial to the slip 8 to produce the required radial outward movement amount.

[0036] In a more specific solution, for the implementation mode in which the tail end 12 is a T-shaped structure and the slot 11 is a T-shaped slot, the inclined surface 13 is located above the maximum width position of the slip 8, and the side surface of the slot 11 is a slope surface that matches the inclined surface 13.

[0037] In a more specific solution, the slips 8 are evenly distributed in a central annular pattern relative to the slip seat 10. In this solution, the slip 8 assembly and the sleeve can be matched to have a relatively uniform contact and extrusion condition in the circumferential direction.

[0038] In a more specific solution, the turns on the clamp spring 9 are stacked along the axial direction of the slip seat 10. In this solution, under the same number of turns of the clamp spring 9, compared with the case where the turns are stacked along the radial direction of the slip seat 10, the clamp spring 9 has a large contact area with the slip 8, so the initial form of the slip 8 can be better constrained; in addition, when the clamp spring 9 contacts the sleeve milling cylinder, the sleeve milling cylinder and the clamp spring 9 have a smaller contact area, which is beneficial to the smooth completion of the sleeve milling of the clamp spring 9.

[0039] The present solution also provides a packer including the slip 8 assembly, and the packer adopts the slip 8 assembly above.

[0040] In a more specific solution, the packer also includes a sealing component arranged above the slip 8 assembly, and the sealing component includes a plurality of rubber tubes 2, spacer rings 4 arranged between the rubber tubes 2, an upper pressure cap 1 arranged at the upper end of the rubber tube 2, and a lower pressure cap 6 arranged at the lower end of the rubber tube 2, and the materials of the spacer rings 4, the upper pressure cap 1 and the lower pressure cap 6 are all made of composite materials. In this solution, the spacer rings 4, the upper pressure cap 1 and the lower pressure cap 6, which are parts with larger outer diameters in the axial direction of the packer, are all designed with composite materials. When these parts are stuck on the casing due to reasons such as casing deformation, the packer can be unsealed and unstuck smoothly and efficiently by milling off the composite materials, based on the fact that the materials of the upper pressure cap 1, the spacer rings 4 and the lower pressure cap 6 are all made of composite materials.

[0041] In a more specific solution, the upper pressure cap 1 and the lower pressure cap 6 are the parts with the largest outer diameter on the packer, and both are made of composite materials, with the maximum outer diameter of φ115 and the maximum outer diameter of the steel body part of φ93.2. When the milling and unstuck operation is carried out, the inner diameter of the milling barrel is φ95-100, specifically, the outer composite part of the packer is milled with an alloy milling barrel with an outer diameter of φ118mm and an inner diameter of φ95mm, ensuring that the packer can be smoothly removed from the well. The packer with related parts made of composite materials can not only ensure the durability of the packer, but also ensure the reliability of the packer. Regarding the installation of the upper pressure cap 1, the lower pressure cap 6 and other parts, in a more specific scheme, the isolation device includes a central tube 3, a joint assembly arranged at the upper end of the central tube 3, an upper liner 5 and a lower liner 15 arranged on the outside of the central tube 3, and a cone installed on the lower end of the upper liner 5. The joint assembly includes an upper joint and a middle joint. The upper pressure cap 1 is threadedly connected to the joint assembly, the rubber cylinder 2 and the spacer ring 4 are sleeved on the outside of the upper liner 5, the lower pressure cap 6 is threadedly connected to the cone, and the cava seat 10 is arranged on the lower liner 15.

[0042] In a more specific solution, the composite material is a fiber-reinforced epoxy resin composite material. The fiber-reinforced epoxy resin composite material is used in this solution, which is an existing material, that is, this solution does not involve the improvement of the material. At the same time, the mechanical performance index of the fiber-reinforced epoxy resin composite material is 15-20% higher than that of conventional composite materials, so as to improve the strength and durability of the packer. At the same time, it is a composite material with excellent strength-to-weight ratio and corrosion resistance, which can withstand high pressure and harsh working environment.

[0043] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and the specific embodiments of the present invention cannot be considered to be limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, other embodiments derived without departing from the technical solution of the present invention should be included in the protection scope of the present invention.

Claims

1. A slip assembly for convenient sleeve milling, comprising a slip seat (10) and slips (8), wherein the slips (8) are multiple in number, each slip (8) is mounted on the slip seat (10) through a clamping groove (11) at the upper end of the slip seat (10), and further comprising a clamping spring (9) wrapped around the slip (8), characterized in that: The retaining spring (9) is a coil-shaped structure wound by a wire or a rod, and both ends of the coil-shaped structure are open. The outer surface of each slip (8) is provided with a retaining spring groove (14) that passes through both sides of the slip (8). The retaining spring (9) passes through the retaining spring groove (14) of each slip (8) and contacts the bottom of the retaining spring groove (14).

2. A slip assembly for convenient milling according to claim 1, characterized in that: The slip (8) comprises a slip body, the material of the slip body is a composite material, and a slip tooth (7) is inlaid on the outer side of the upper end of the slip body.

3. A slip assembly for convenient milling according to claim 1, characterized in that: The tail end (12) of the slip (8) is a T-shaped structure with the maximum width located at the lower end of the tail end (12). Each slip (8) is provided with a slot (11). The slot (11) is a T-shaped slot with the maximum width located at the lower end of the slot (11). The tail end (12) is embedded in the slot (11), and the lower end of the tail end (12) is embedded in the lower end of the slot (11). The width of the lower end of the tail end (12) is greater than the width of the upper end of the slot (11).

4. A slip assembly for convenient milling according to claim 1, characterized in that: Both sides of the tail end (12) of the slip (8) are provided with inclined surfaces (13) with the slope facing the outside of the slip (8), and the position where the side wall of the groove (11) acts on the tail end (12) is located on the inclined surfaces (13).

5. A slip assembly for convenient milling according to any one of claims 1 to 4, characterized in that: The slips (8) are evenly distributed in a ring shape relative to the center of the slip seat (10).

6. A slip assembly for convenient milling according to any one of claims 1 to 4, characterized in that: The turns on the clamping spring (9) are stacked along the axial direction of the slip seat (10).

7. A packer, characterized in that: A slip assembly comprising any one of claims 1 to 6.

8. The packer according to claim 7, characterized in that: The packer further comprises a sealing assembly arranged above the slip assembly, the sealing assembly comprising a plurality of rubber tubes (2), spacer rings (4) arranged between the rubber tubes (2), an upper pressure cap (1) arranged at the upper end of the rubber tubes (2), and a lower pressure cap (6) arranged at the lower end of the rubber tubes (2), wherein the spacer rings (4), the upper pressure cap (1) and the lower pressure cap (6) are all made of composite materials.

9. The packer according to claim 8, characterized in that: The packer comprises a central tube (3), a joint assembly arranged at the upper end of the central tube (3), an upper liner (5) and a lower liner (15) arranged outside the central tube (3), and a cone installed at the lower end of the upper liner (5); the upper pressure cap (1) is threadedly connected to the joint assembly, the rubber cylinder (2) and the spacer ring (4) are sleeved on the outer side of the upper liner (5), the lower pressure cap (6) is threadedly connected to the cone, and the cava seat (10) is arranged on the lower liner (15).

10. The packer according to claim 8 or 9, characterized in that: The composite material is a fiber-reinforced epoxy resin composite material.

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