Milling semi-open type split composite material lock sleeve structure

Abstract

The utility model belongs to the technical field of oil well engineering, and particularly relates to a milling semi-open type split composite material lock sleeve structure which comprises an outer sleeve body and an inner sleeve body, the outer circle of the outer sleeve body is provided with threads connected with an outer barrel of a packer, and the inner side of the outer sleeve body is provided with a mounting cavity; the inner sleeve body is coaxially arranged in the mounting cavity of the outer sleeve body, and inner teeth meshed with the central pipe are arranged on the inner wall of the inner sleeve body; the outer sleeve body is made of a milling material, and the inner sleeve body is made of a high-strength material; therefore, the same lock sleeve has the dual performance of high-strength meshing and efficient casing milling and unfreezing at the same time, during unfreezing, the outer sleeve body can be quickly milled away, and the casing milling efficiency is improved.

Description

Technical Field

[0001] This utility model relates to the field of oil well engineering technology, specifically to a millable, semi-open, split composite material locking sleeve structure. Background Technology

[0002] In oilfield well completion and workover operations, packers are key downhole tools for achieving processes such as section isolation, stratified water injection, and fracturing acidizing. As the core component of the packer, the locking sleeve (or locking mechanism) is responsible for axial locking and torque transmission after setting. The reliability and maneuverability of its structure directly affect the safety and operational efficiency of the tool.

[0003] In existing technologies, such as the packer disclosed in Chinese patent CN103334713A, the setting and locking mechanism mainly consists of metal components such as an upper outer sleeve, piston, locking spring, and connecting sleeve. This locking mechanism achieves locking after setting by the cooperation of locking teeth on the outer periphery of the piston and the locking spring. The entire device is made of metal and possesses high meshing strength and load-bearing capacity. Furthermore, when releasing the packer, it can be preferentially released by throwing a ball, applying pressure, or lifting. If these methods fail, the upper cone, barrel-shaped slips, and other components can be destroyed through drilling and milling to achieve release.

[0004] However, this type of existing technology still has shortcomings. When the packer needs to be drilled and milled to release the jamming, the insertion tube sealing mechanism must be removed first by rotating it forward, and then the sleeve milling cylinder must be lowered to drill and remove the upper cone, barrel-shaped slips and other components, making the operation steps complicated. Summary of the Invention

[0005] In order to overcome the shortcomings of the existing technology, the purpose of this utility model is to provide a milling-compatible semi-open split composite material locking sleeve structure, so that the same locking sleeve has the dual performance of high-strength engagement and efficient milling and unblocking. When unblocking, the outer sleeve can be quickly milled off, improving the milling efficiency.

[0006] The technical solution adopted in this utility model is as follows:

[0007] A millable semi-open split composite material locking sleeve structure includes an outer sleeve and an inner sleeve. The outer sleeve has a thread on its outer circle that connects to the outer cylinder of a packer, and an installation cavity is provided on the inner side of the outer sleeve. The inner sleeve is coaxially disposed in the installation cavity of the outer sleeve, and the outer sleeve and the inner sleeve are interference-fitted. The inner wall of the inner sleeve has internal teeth that mesh with the central tube.

[0008] The outer sleeve is made of millable material, and the inner sleeve is made of high-strength material;

[0009] The high-strength material is made of alloy steel or nickel-based alloy, and the millingable material is made of aluminum alloy, glass fiber reinforced epoxy resin or carbon fiber reinforced epoxy resin.

[0010] The outer casing is provided with multiple sets of anti-rotation holes and shear pin holes in the outer circumference; the outer casing is composed of two semi-cylinders, and each of the two semi-cylinders is provided with a mounting plate at the upper and lower parts. The two sets of anti-rotation holes are threaded holes and are respectively set on the corresponding mounting plates. During installation, the corresponding mounting plates overlap and are fixed by screws to the two corresponding anti-rotation holes.

[0011] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0012] 1. The outer sleeve is made of milling-compatible material. When jamming occurs downhole and milling is required to release the jamming, the sleeve can be directly milled, and the outer sleeve can be quickly removed, forming a clear priority destruction path and improving milling efficiency. The inner sleeve is made of high-strength material, specifically designed to bear the high contact stress and torque transmission at the meshing point between the internal teeth and the central tube, ensuring the strength and reliability of the locking mechanism. The split structure decomposes the sleeve into independent outer and inner sleeves, achieving functional separation design. The difference in materials between the inner and outer sleeves allows the same sleeve to simultaneously possess the dual performance of high-strength meshing and efficient milling release, overcoming the technical contradiction that traditional one-piece metal sleeves cannot achieve both.

[0013] 2. Mounting plates are provided on both the upper and lower parts. They overlap during installation to form a multi-point connection, ensuring the structural strength and coaxiality of the outer sleeve after it is closed. The anti-rotation hole is a threaded hole. During installation, the overlapping mounting plates are fixed with screws. Due to the interference fit, the outer sleeve and inner sleeve can rotate coaxially. At the same time, it realizes the dual functions of closing and fixing the two half cylinders and anti-rotation connection, simplifying the structure. The split outer sleeve is more easily damaged during milling, further reducing the milling resistance.

[0014] 3. Aluminum alloys have the characteristics of low density and low cutting resistance, which can achieve overall lightweighting of the locking sleeve while ensuring sufficient structural strength of the outer sleeve; the hardness of aluminum alloys is much lower than that of steel, resulting in low cutting resistance and low drill wear during sleeve milling, further improving sleeve milling efficiency; aluminum alloys have good machinability, which facilitates the forming and assembly of the outer sleeve.

[0015] 4. The anti-rotation holes and shear pin holes are set circumferentially, and can form a multi-point anti-rotation connection with the outer cylinder or central tube of the packer through anti-rotation screws and shear pins; the multi-point anti-rotation structure effectively prevents the locking sleeve assembly from rotating relative to each other when subjected to torque, ensuring the stability of torque transmission; the anti-rotation and limiting functions are integrated on the outer sleeve, with a compact structure and easy assembly.

[0016] 5. The interference fit achieves a gapless fit between the inner and outer sleeves, ensuring their coaxiality and the accuracy of the meshing position between the inner sleeve's internal teeth and the central tube.

[0017] In a preferred embodiment of this utility model, the outer circumference of the inner sleeve is provided with an annular groove for injecting adhesive.

[0018] Beneficial effects: Adhesive can be injected into the annular groove, allowing for adhesive bonding and fixation between the inner and outer sleeves. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the outer sleeve in Embodiment 1 of the millable semi-open split composite material locking sleeve structure of this utility model;

[0020] Figure 2 This is a schematic diagram of the inner sleeve of Embodiment 1 of the millable semi-open split composite material locking sleeve structure of this utility model;

[0021] Figure 3 This is a three-dimensional sectional view of the assembled semi-open split composite material locking sleeve structure of this utility model, according to Embodiment 1.

[0022] Figure 4 This is an exploded view of Embodiment 1 of the millable semi-open split composite material locking sleeve structure of this utility model.

[0023] The reference numerals in the attached drawings include: outer sleeve 1, mounting cavity 11, anti-rotation hole 12, shear pin hole 13, inner sleeve 2, inner teeth 21, annular groove 22, half cylinder 3, and mounting plate 31. Detailed Implementation

[0024] Typical embodiments embodying the features and advantages of this utility model will be specifically described in the following description. It should be understood that this utility model can have various variations in different embodiments, all of which do not depart from the scope of this utility model, and the descriptions and illustrations therein are intended to limit this utility model in nature.

[0025] In the description of this application, the terms "first", "second", etc. are used only for the convenience of describing this application and simplifying the description, and are not intended to indicate or imply that the structure referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0026] See Figures 1 to 3 As shown, this embodiment discloses a millable semi-open split composite material locking sleeve structure, including an outer sleeve and an inner sleeve. The outer sleeve has a thread on its outer circumference that connects to the outer cylinder of the packer, and an installation cavity is provided on the inner side of the outer sleeve. The inner sleeve is coaxially disposed in the installation cavity of the outer sleeve, and the inner wall of the inner sleeve has internal teeth that mesh with the central tube. The outer sleeve is made of millable material, and the inner sleeve is made of high-strength material. The outer sleeve and the inner sleeve are interference-fitted together.

[0027] In this embodiment, the high-strength material in the inner sleeve is alloy steel (42CrMo, 40CrNiMo, 35CrMo), or a nickel-based alloy. The millable material in the outer sleeve is aluminum alloy, or a composite material (glass fiber reinforced epoxy resin (GFRP), carbon fiber reinforced epoxy resin (CFRP)) can be used.

[0028] The outer casing is provided with multiple sets of anti-rotation holes and shear pin holes in the outer circumference, which are formed by... Figure 1 It can be seen that there are four groups in total, with one longitudinal row along the axis forming one group. Each group has three anti-rotation holes and one shear pin hole.

[0029] The inner sleeve has an annular groove on its outer circumference for gluing, which allows for adhesive bonding.

[0030] The working principle of this embodiment is as follows:

[0031] The semi-open split locking structure consists of an outer sleeve and an inner sleeve. The outer sleeve is a cylindrical part with threads or mating surfaces on its outer circumference that connect to the outer cylinder of the packer or the connector. The axial locking of the tubing and torque transmission are achieved through the engagement of the inner sleeve and the locking teeth.

[0032] Material zoning and strength coordination: The outer sleeve body is made of composite materials or a combination of composite materials and aluminum alloys, which is used to support the overall structure and serve as the main body for milling failure during downhole unloading operations; the inner sleeve body is made of high-strength metal materials, which is used to bear the contact stress and torque transmission at the meshing point of the internal teeth and locking teeth, so that the locking sleeve has milling capability and lightweight characteristics while ensuring the strength and rigidity of the meshing area.

[0033] Multi-point anti-rotation and force stability: The outer sleeve of the lock sleeve is provided with several evenly distributed anti-rotation holes and shear pin holes (keyways can also be used in other embodiments). The anti-rotation holes, shear pin holes or keyways cooperate with the central tube or other force transmission components through anti-rotation screws, shear pins or keys to form multi-point anti-rotation connection and axial limit, preventing the lock sleeve from relative rotation or axial movement when subjected to torque and axial load, and ensuring the stability of the packer locking operation.

[0034] The semi-open connection and milling path lock sleeve inner sleeve and lock sleeve outer sleeve are fixed in the axial and circumferential directions through interference fit, positioning step fit and screw or pin fixation. The outer sleeve adopts a semi-open or split structure. After the inner and outer sleeves are assembled, they form a complete lock sleeve assembly. Under normal working conditions, it transmits load as an integrated lock sleeve. When milling operation is required, the outer sleeve is milled off first, and the inner sleeve is gradually destroyed when the force reaches the set limit, so as to improve the unlocking efficiency.

[0035] Example 2

[0036] See Figure 4Based on Embodiment 1, the outer sleeve is composed of two semi-cylinders, each with mounting plates at its upper and lower parts. Two sets of anti-rotation holes are threaded holes and are located on the corresponding mounting plates (each mounting plate has three anti-rotation holes and shear pin holes). During installation, the corresponding mounting plates overlap and are fixed using the anti-rotation holes. The outer sleeve adopts a two-semi-cylinder split structure, facilitating the installation and disassembly of the inner sleeve and reducing assembly difficulty. Mounting plates are provided at both the upper and lower parts, overlapping during installation to form a multi-point connection, ensuring the structural strength and coaxiality of the closed outer sleeve. The anti-rotation holes are threaded holes, and screws are used to fix the overlapping mounting plates during installation, simultaneously achieving the dual functions of fixing the two semi-cylinders and preventing rotation, simplifying the structure. The split outer sleeve is more easily damaged during milling, further reducing milling resistance.

[0037] The above embodiments are merely preferred embodiments of this utility model and should not be construed as limiting the scope of protection of this utility model. Any non-substantial changes and substitutions made by those skilled in the art based on this utility model shall fall within the scope of protection claimed by this utility model.

Claims

1. A millable, semi-open, split composite material locking sleeve structure, characterized in that: It includes an outer sleeve and an inner sleeve. The outer sleeve has a thread on its outer circle that connects to the outer cylinder of the packer, and an inner cavity is provided on its inner side. The inner sleeve is coaxially disposed in the mounting cavity of the outer sleeve. The outer sleeve and the inner sleeve are interference-fitted. The inner wall of the inner sleeve is provided with internal teeth that mesh with the central tube. The outer sleeve is made of millable material, and the inner sleeve is made of high-strength material; The high-strength material is made of alloy steel or nickel-based alloy, and the millingable material is made of aluminum alloy, glass fiber reinforced epoxy resin or carbon fiber reinforced epoxy resin. The outer casing is provided with multiple sets of anti-rotation holes and shear pin holes in the outer circumference; the outer casing is composed of two semi-cylinders, and each of the two semi-cylinders is provided with a mounting plate at the upper and lower parts. The two sets of anti-rotation holes are threaded holes and are respectively set on the corresponding mounting plates. During installation, the corresponding mounting plates overlap and are fixed by screws to the two corresponding anti-rotation holes.

2. The millable semi-open split composite material locking sleeve structure according to claim 1, characterized in that: The outer circumference of the inner sleeve is provided with an annular groove for injecting adhesive.

Images