Multi-layer rubber combined casing pipe capable of preventing casing pipe deformation and preparation method of multi-layer rubber combined casing pipe

Abstract

The invention relates to a multi-layer rubber combined casing pipe capable of preventing casing pipe deformation and a preparation method thereof.The multi-layer rubber combined casing pipe comprises a casing pipe body and a rubber combined layer, the rubber combined layer is fixed to the outer side wall of the casing pipe body in a vulcanized mode, the rubber combined layer comprises multiple rubber layers which are sequentially stacked and fixed from inside to outside, and the rubber layers are fixed to the outer side wall of the casing pipe body in a vulcanized mode. And the water absorption expansion rates of the multiple rubber layers are sequentially increased from inside to outside. According to the multi-layer rubber combined casing pipe capable of preventing casing pipe deformation, the expansibility and the pressure bearing performance of the rubber layer are both considered, the problem that fluid channeling is caused in the fracturing process due to the fact that a traditional casing pipe bears insufficient pressure after expansion is solved, meanwhile, the surface layer is treated, the rubber layer is effectively prevented from expanding in advance before entering a well, and on-site safe construction is ensured. By designing multiple rubber layers with different expansion rates, the contradiction between the expansibility and the pressure-bearing property is solved, and the high pressure-bearing property of the rubber layers can be realized while the high expansibility of rubber is ensured.

Description

Technical Field

[0001] This invention relates to the field of oil and gas development technology, specifically to a multi-layer rubber composite casing for preventing casing deformation and its preparation method. Background Technology

[0002] Currently, casing deformation of varying degrees has occurred during shale oil development. In particular, as shale gas moves into deeper areas, casing deformation becomes more prominent, leading to increased fracturing costs and difficulties, a reduction in the number of fracturing stages, and serious consequences such as low single-well production and short well lifecycles.

[0003] Regarding the causes of casing deformation during fracturing, Chen Chaowei, Xiang Degui, and others, through the analysis of extensive field data, proposed a fluid channel-fault activation model, revealing the mechanism of casing deformation in shale oil and gas reservoirs: due to the development of fracture systems in shale oil and gas reservoirs, hydraulic fracturing induces fracture slippage, and the shear displacement generated by fracture slippage directly acts on the casing, leading to casing deformation. On the other hand, statistical analysis of field data shows that the casing deformation is limited, mainly distributed in the range of 15-25 mm, and does not cause shearing of the oil layer casing. Since fracture slippage is a displacement loading process, the slippage force approaches infinity, and conventional measures such as increasing the casing steel grade and wall thickness cannot fundamentally solve the problem of casing deformation.

[0004] To prevent casing deformation during fracturing, Xiang Degui, Chen Chaowei, and others proposed the concept of "using flexibility to overcome rigidity." CNPC engineering and technical researchers developed a rubber composite casing, mainly composed of the oil layer casing and a water-absorbing, expandable rubber casing located outside the oil layer casing (patents CN212671582U, CN207177747U, CN106761443B). The specific idea is to add an elastic rubber sleeve to the outer layer of the casing, i.e., to run the rubber composite casing. In high-risk well sections with fracture slippage, the rubber composite casing is run. During fracturing, if slippage occurs, the outer rubber layer can absorb the slippage displacement, thus protecting the inner casing from being affected. The addition of a rubber sleeve to the casing increases the resistance during casing installation. To reduce this resistance, a special rubber that does not swell in oil but swells in water is used. This prevents expansion during casing installation in oil-based environments, ensuring safe installation. After installation, the rubber absorbs water and expands during the thickening of the cementing slurry, further increasing its thickness and maximizing its ability to absorb displacement loads. Based on this, to further enhance the rubber's water absorption, patent CN115822509A designed a rubber composite casing with alternating slots. To prevent damage to the rubber layer on irregular well walls during installation, patent CN118110430A designed a self-expanding rubber composite casing by adding a soluble cover. To prevent excessive expansion of the rubber layer, patent CN118088067A designed an elastic protective cover, creating a rubber composite casing and its usage method to prevent excessive expansion.

[0005] Regarding the aforementioned technical approach, the existing rubber casing assembly structure is relatively simple and has the following two problems: First, when considering the expansion characteristics to absorb formation displacement, the pressure-bearing characteristics are not taken into account. If the strength after expansion is insufficient, it will lead to inadequate annular sealing, affecting the integrity of the wellbore during fracturing. The horizontal well segmented fracturing process uses bridge plugs to isolate horizontal well sections, with multiple perforations in each section, allowing fracturing fluid to enter the formation through multiple perforations to form a fracture network. If the rubber's pressure-bearing capacity is insufficient, resulting in poor wellbore sealing, high-pressure fluid can easily flow along the rubber layer during fracturing, causing fluid leakage between clusters and sections, thus affecting the fracturing effect and wellbore integrity. Second, the rubber layer expands rapidly upon contact with water. Before being run into the well, during transportation, storage, hoisting, and wellhead installation, it inevitably comes into contact with water due to weather and environmental factors. How to prevent premature expansion before running into the well is also a problem that needs to be solved. Therefore, there is an urgent need to design a high-pressure, water-swellable rubber composite casing that prevents casing deformation, taking into account both the expansibility and pressure resistance of the rubber layer. This solves the problem of insufficient pressure resistance after expansion of traditional casing, which leads to fluid leakage during fracturing. At the same time, surface treatment effectively prevents the rubber layer from expanding prematurely before entering the well, ensuring safe construction on site. Summary of the Invention

[0006] This invention addresses the problem of insufficient pressure bearing capacity of conventional rubber composite casing after the rubber layer expands, leading to fluid leakage between clusters or segments during fracturing and premature expansion during casing installation. It provides a multi-layer rubber composite casing that prevents casing deformation and its preparation method.

[0007] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: a multi-layer rubber composite sleeve for preventing sleeve deformation, comprising a sleeve body and a rubber composite layer, wherein the rubber composite layer is vulcanized and fixed on the outer side wall of the sleeve body, and the rubber composite layer comprises multiple layers of rubber layers stacked and fixed sequentially from the inside to the outside, wherein the water absorption and expansion rate of the multiple layers of rubber layers increases sequentially from the inside to the outside.

[0008] The beneficial effects of this invention are as follows: This invention's multi-layer rubber composite casing, designed to prevent casing deformation, balances the expansibility and pressure-bearing capacity of the rubber layers. It solves the problem of insufficient pressure bearing capacity after expansion, leading to fluid leakage during fracturing, which is a common issue with traditional casings. Furthermore, surface treatment effectively prevents premature expansion of the rubber layers before well insertion, ensuring safe on-site construction. This invention resolves the contradiction between expansibility and pressure bearing capacity by designing rubber layers with various expansion rates. It ensures both high expansibility and high pressure bearing capacity of the rubber layers. This design effectively absorbs formation displacement and prevents casing deformation without affecting fracturing performance, thus improving the overall efficiency of shale oil and gas development.

[0009] Based on the above technical solution, the present invention can be further improved as follows.

[0010] Furthermore, the thickness of the multilayer rubber layer gradually increases from the inside to the outside, and the thickness difference between two adjacent rubber layers is 1 to 2 mm; or, in the multilayer rubber layer, the outermost rubber layer has the smallest thickness, and the thickness of the remaining rubber layers is equal.

[0011] Furthermore, the rubber composite layer comprises 2 to 4 rubber layers.

[0012] Furthermore, the total thickness of the rubber composite layer is 12-30 mm; in the multilayer rubber layer, the thickness of the outermost rubber layer is 4-6 mm.

[0013] Furthermore, the rubber composite layer is embedded with multiple layers of adhesive-friendly mesh material, and the multiple layers of adhesive-friendly mesh material are equally spaced in the rubber composite layer.

[0014] The beneficial effects of adopting the above-mentioned further solution are: by setting multiple layers of adhesive mesh material, the structural strength of the rubber composite layer is further enhanced, and the balance between expansion and pressure resistance is effectively achieved.

[0015] Furthermore, the spacing between two adjacent layers of adhesive mesh material is 2-3 mm; the adhesive mesh material layer is a curtain fabric with a thickness of 0.5-1 mm and a mesh count of 40-100.

[0016] Furthermore, the rubber composite layer is provided with multiple sets of countersunk holes arranged in a ring along the outer periphery of the casing body, and the countersunk holes are arranged through multiple rubber layers and multiple adhesive mesh material layers.

[0017] The beneficial effects of adopting the above-mentioned further scheme are: these countersunk holes can provide more water storage space, giving the inner rubber, which absorbs water slowly, sufficient time to absorb water. Since the pumping time of the pre-fluid is short during cementing (generally 10-20 minutes), the outer rubber may not absorb enough water. The more water stored through these countersunk holes ensures that the inner rubber, which absorbs water slowly, can expand effectively.

[0018] Furthermore, the diameter of the countersunk hole is 10-20 mm, the ring spacing of the multiple sets of countersunk holes is 50-100 mm, and the number of countersunk holes in each set is 30-40.

[0019] Furthermore, a waterproof layer is provided on the outer wall of the rubber composite layer, and the thickness of the waterproof layer is 1 to 3 mm.

[0020] The beneficial effect of adopting the above-mentioned further solution is that the surface is wrapped with a waterproof material that dissolves at a certain temperature, preventing it from swelling due to water exposure before entering the well.

[0021] A method for preparing a multi-layer rubber composite sleeve to prevent sleeve deformation includes the following steps:

[0022] S1, perform surface pretreatment on the surface of the casing body;

[0023] S2, multiple rubber layers are wrapped around the surface of the casing body, and adhesive mesh material layers are arranged at intervals. Adhesive is placed between the adhesive mesh material layers and the rubber layers, and between the rubber layers and the casing body.

[0024] S3, vulcanize the multi-layer rubber layer to ensure a strong bond between the rubber layer and the casing body, between adjacent rubber layers, and between the rubber layer and the adhesive mesh material layer.

[0025] S4. After the entire rubber composite layer has been vulcanized, a perforation operation is performed on the outer surface of the rubber composite layer.

[0026] S5. After drilling, a waterproof material is evenly sprayed onto the outer surface of the rubber composite layer to obtain a multi-layer rubber composite sleeve.

[0027] The beneficial effects of this invention are: the preparation method of this invention is convenient to operate, and the multi-layer rubber composite casing obtained to prevent casing deformation effectively absorbs formation displacement and prevents casing deformation without affecting the fracturing effect, thereby improving the overall efficiency of shale oil and gas development. Attached Figure Description

[0028] Figure 1 A schematic diagram of inter-fracturing crosstalk during fracturing of a traditional single-expansion-rate rubber composite casing. Figure 1 ;

[0029] Figure 2 A schematic diagram of inter-fracturing crosstalk during fracturing of a traditional single-expansion-rate rubber composite casing. Figure 2 ;

[0030] Figure 3 This is a schematic diagram of the longitudinal section structure of the multi-layer rubber composite sleeve for preventing sleeve deformation according to the present invention. Figure 1 ;

[0031] Figure 4 This is a schematic diagram of the longitudinal section structure of the multi-layer rubber composite sleeve for preventing sleeve deformation according to the present invention. Figure 2 ;

[0032] Figure 5 This is a schematic diagram of the cross-sectional structure of the multi-layer rubber composite sleeve for preventing sleeve deformation according to the present invention.

[0033] The attached diagram lists the components represented by each number as follows:

[0034] 1. Irregular well wall; 2. Cement slurry; 3. Single rubber layer; 4. Fracturing fractures of different clusters; 5. Fracture; 6. Casing body; 7. Inner rubber layer; 8. Adhesive mesh material layer; 9. Middle rubber layer; 10. Outer rubber layer; 11. Countersunk hole; 12. Waterproof layer. Detailed Implementation

[0035] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0036] Figure 1 This diagram illustrates inter-fracture crosstalk during fracturing of a traditional single-expansion-rate rubber composite casing. A single rubber layer 3 encases the casing, with cement slurry 2 and an irregular wellbore 1 on the outside. Different clusters of fracturing fractures 4 apply radial pressure to the casing encased in the single rubber layer 3, causing axial movement of the casing. During fracturing, inter-fracture fluid crosstalk forms fractures 5. The poor interface between the cement slurry 2 and the single rubber layer 3 causes fluid to crosstalk along the interface, such as... Figure 2 As shown, the direction indicated by the arrow is the direction of fluid flow at the interface.

[0037] like Figures 3-5As shown in the figure, a multi-layer rubber composite sleeve for preventing sleeve deformation in this embodiment includes a sleeve body 6 and a rubber composite layer. The rubber composite layer is vulcanized and fixed on the outer side wall of the sleeve body 6. The rubber composite layer includes multiple rubber layers stacked and fixed from the inside to the outside, and the water absorption expansion rate of the multiple rubber layers increases from the inside to the outside.

[0038] Specifically, in this embodiment, the sleeve body 6 has a cylindrical structure and is the basic component of this embodiment. The rubber composite layer consists of multiple layers of rubber with different water absorption and expansion rates. The inner layer of rubber has a slow water absorption rate, while the outer layer of rubber has a fast water absorption and expansion rate. The rubber composite layer is located on the outside of the sleeve body and is fixed to the sleeve body by vulcanization bonding.

[0039] In this embodiment, the arrangement of the multi-layer rubber layers can be selected in two ways. One is that the thickness of the multi-layer rubber layers gradually increases from the inside to the outside, and the thickness difference between two adjacent rubber layers is 1 to 2 mm, such as 1 mm, 1.2 mm, 1.4 mm, 1.6 mm, 1.7 mm, 1.8 mm, 2 mm, etc. The other is that the outermost rubber layer has the smallest thickness, and the thickness of the remaining rubber layers is equal.

[0040] Specifically, the rubber composite layer includes 2 to 4 rubber layers.

[0041] Preferred, such as Figures 3-5 As shown, the rubber composite layer comprises three rubber layers: an inner rubber layer 7, a middle rubber layer 9, and an outer rubber layer 10. The inner rubber layer 7 has the slowest expansion rate, the middle rubber layer 9 has a moderate expansion rate, and the outer rubber layer 10 has the fastest expansion rate.

[0042] Specifically, the total thickness of the rubber composite layer is 12-30mm, and can be selected from 12mm, 14mm, 16mm, 18mm, 20mm, 22mm, 24mm, 26mm, 28mm, 30mm, etc.; in the multi-layer rubber layer, the thickness of the outermost rubber layer is 4-6mm, and can be selected from 4mm, 4.2mm, 4.4mm, 4.6mm, 4.8mm, 5mm, 5.2mm, 5.4mm, 5.6mm, 5.8mm, 6mm, etc.

[0043] like Figures 3-5 As shown, in this embodiment, the rubber composite layer is embedded with multiple layers of adhesive-friendly mesh material 8, which are evenly spaced within the rubber composite layer. By providing multiple layers of adhesive-friendly mesh material, the structural strength of the rubber composite layer is further enhanced, and an effective balance is achieved between expansion and compressive strength.

[0044] Specifically, the spacing between two adjacent layers of adhesive mesh material 8 is 2-3 mm, and can be selected from 2 mm, 2.2 mm, 2.4 mm, 2.6 mm, 2.7 mm, 2.8 mm, 3 mm, etc.; the adhesive mesh material layer 8 is a curtain fabric, the thickness of which is 0.5-1 mm, and can be selected from 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, etc.; the mesh count of which is 40-100 mesh, and can be selected from 40 mesh, 45 mesh, 50 mesh, 55 mesh, 60 mesh, 65 mesh, 70 mesh, 75 mesh, 80 mesh, 85 mesh, 90 mesh, 95 mesh, 100 mesh. In this embodiment, each rubber layer is also composed of multiple layers of rubber, so it is convenient to place the curtain fabric between the rubber forming each rubber layer, and different spacings of the curtain fabric can be set as needed.

[0045] like Figure 5 As shown, the rubber composite layer in this embodiment has multiple sets of countersunk holes 11 arranged in a ring along the outer periphery of the casing body 6. These countersunk holes 11 penetrate multiple layers of rubber and multiple layers of adhesive mesh material 8. These countersunk holes provide more water storage space, allowing sufficient time for the inner, slow-absorbing rubber to absorb water. Since the pumping time of the pre-fluid is short during cementing (generally 10-20 minutes), the outer rubber layer may not absorb enough water. The increased water storage through these countersunk holes ensures effective expansion of the inner, slow-absorbing rubber layer.

[0046] Specifically, the diameter of the countersunk hole 11 is 10-20mm, and can be selected from 10mm, 12mm, 14mm, 16mm, 17mm, 18mm, 20mm, etc.; the ring spacing of multiple sets of countersunk holes 11 is 50-100mm, and can be selected from 50mm, 55mm, 60mm, 65mm, 70mm, 75mm, 80mm, 85mm, 90mm, 95mm, 100mm, etc.; the number of countersunk holes 11 in each set is 30-40, and can be selected from 30, 32, 34, 36, 37, 38, 40, etc.

[0047] like Figures 3-5As shown, in this embodiment, a waterproof layer 12 is also provided on the outer wall of the rubber composite layer. The thickness of the waterproof layer 12 is 1-3mm, and can be selected from 1mm, 1.2mm, 1.4mm, 1.6mm, 1.7mm, 1.8mm, 2.0mm, 2.2mm, 2.4mm, 2.6mm, 2.8mm, 3mm, etc. A waterproof material that dissolves at a certain temperature is wrapped on the surface to prevent the rubber composite layer from swelling with water before entering the well. Furthermore, the dissolution of the waterproof layer under the wellbore temperature conditions does not affect subsequent water absorption and expansion. The thickness of the waterproof layer is 1-3mm; too thin and it will not provide waterproofing, too thick and it will affect the overall size of the rubber casing and increase the difficulty of lowering it. Before lowering into the well, if rain or humid weather is encountered, the outer layer of water-swellable rubber will expand rapidly upon contact with water, leading to difficulties in lowering and affecting construction risks. Furthermore, the expanded rubber layer will have reduced strength, causing wear during lowering and weakening its ability to absorb formation displacement, thus failing to prevent casing deformation. Simultaneously, it is required that the material can detach at temperatures of 40-80℃, thereby enabling automatic dissolution during the casing running process after casing insertion at wellbore temperatures, without affecting its water absorption and expansion function during cementing after casing installation. These waterproof materials can be polyurea materials, polyvinyl alcohol, etc.

[0048] The rubber used in this embodiment is a type of rubber that does not swell in the presence of oil but swells in the presence of water. The casing installation process is carried out with the wellbore filled with oil-based drilling fluid. During this process, the rubber composite layer must not swell prematurely upon contact with oil; otherwise, premature expansion can easily lead to wellbore blockage, making it impossible to ensure the safe completion of the casing installation and causing construction risks. During cementing after casing installation, the outer rubber layer rapidly absorbs a large amount of water. While expanding on its own, it also permeates and transfers water inwards, allowing the inner rubber layer sufficient time to absorb water and further expand while ensuring sufficient strength. The countersinking of the rubber layer further increases the water absorption area.

[0049] Because rubber has the characteristic of decreasing strength after absorbing water, compared to conventional rubber composite casings made of water-absorbing and swelling rubber materials (patents CN212671582U, CN207177747U, CN106761443B, CN115822509A, CN118110430A, CN118088067A), if the water absorption and swelling rate is fast, the strength will decrease rapidly. This can lead to the risk of fluid crosstalk between different fracturing clusters and different fracturing sections during fracturing, thereby affecting the fracturing effect. In severe cases, annular pressure may occur, affecting the integrity of the wellbore and causing economic losses and safety risks. In this embodiment, rubber layers with different expansion rates are used. The outer rubber absorbs water to ensure the main expansion amount, which is used to absorb most of the slippage of the formation. Due to its low strength, it does not bear pressure. The inner rubber absorbs water slowly. By absorbing water stored in the outer rubber and the sinkhole, it further expands and absorbs a portion of the slippage of the formation. At the same time, it also has higher strength than the outer rubber. By compressing the outer rubber, the rubber layer and the cement ring have good sealing ability and high pressure bearing capacity.

[0050] The water-swellable rubber material used in the rubber composite layer mainly consists of nitrile rubber, sodium polyacrylate, polyvinyl chloride, carbon black, silica, calcium sulfate whiskers, anhydrous ethanol, polyurethane prepolymer, zinc oxide, stearic acid, anti-aging agent, sulfur, and other components. The proportions vary for different layers at different expansion rates. The outermost rubber layer is designed to expand to 20%-40% within 20 minutes, with a tensile strength greater than 3 MPa, elongation at break greater than 500%, and tear strength greater than 15 kN / m after expansion. The inner rubber layer expands to 10%-20%, with a tensile strength greater than 6 MPa, elongation at break greater than 850%, and tear strength greater than 35 kN / m after expansion.

[0051] To further improve the overall strength of the rubber layer, especially addressing the issue of rubber softening under high-temperature conditions, high-strength, rubber-compatible mesh materials (such as polyester cord fabric or aramid cord fabric) are embedded within the rubber layer. These are spaced evenly within the rubber composite layer. This significantly enhances the overall strength of the rubber layer and suppresses lateral deformation along the casing axis, preventing fluid pressure from causing deformation and crosstalk during fracturing. The addition of cord fabric to the rubber layer ultimately achieves a pressure-bearing capacity greater than 70 MPa, enabling limited isolation between clusters and fractures during fracturing in deep oil and gas reservoirs, thus preventing fluid crosstalk.

[0052] This embodiment of the multi-layer rubber composite casing for preventing casing deformation balances the expansibility and pressure-bearing capacity of the rubber layers, solving the problem of insufficient pressure bearing capacity after expansion in traditional casings, which leads to fluid leakage during fracturing. Simultaneously, surface treatment effectively prevents premature expansion of the rubber layers before well insertion, ensuring safe on-site construction. By designing multiple rubber layers with different expansion rates, the contradiction between expansibility and pressure bearing capacity is resolved, ensuring both high expansibility and high pressure bearing capacity of the rubber layers. This design effectively absorbs formation displacement and prevents casing deformation without affecting fracturing performance, thus improving the overall efficiency of shale oil and gas development.

[0053] This embodiment also provides a method for preparing a multi-layer rubber composite sleeve to prevent sleeve deformation, including the following steps:

[0054] S1. Perform surface pretreatment on the surface of the casing body 6; perform surface cleaning and sandblasting on the casing body 6 to remove oil, rust and impurities, increase surface roughness, and ensure the adhesion between the rubber and the casing body 6.

[0055] S2, multiple rubber layers are wrapped around the surface of the sleeve body 6, and adhesive mesh material layers 8 are arranged at intervals. Adhesive is placed between the adhesive mesh material layers 8 and the rubber layers, and between the rubber layers and the sleeve body.

[0056] S3, vulcanize the multi-layer rubber to make the rubber layer firmly bonded to the casing body 6, between adjacent rubber layers, and between the rubber layer and the adhesive mesh material layer 8.

[0057] The contact surfaces between the adhesive mesh material layer and the rubber must be cleaned. Adhesive is placed between the casing body and the rubber, and between the rubber and the adhesive mesh material layer. The casing body, wrapped with the rubber layer, is then vulcanized at high temperature to ensure a strong bond between the rubber layer and the casing body, and between the rubber and the adhesive mesh material layer. High-temperature vulcanization enhances the physical properties of the rubber, ensuring its stability and high strength in high-temperature wellbore environments.

[0058] S4. After the entire rubber composite layer has been vulcanized, a perforation operation is performed on the outer surface of the rubber composite layer.

[0059] S5. After drilling, a waterproof material (polyurea, polyvinyl alcohol, etc.) is evenly sprayed onto the outer surface of the rubber composite layer to ensure rapid dissolution at temperatures ranging from 40 to 80°C, thus obtaining a multi-layer rubber composite sleeve. The processed rubber composite sleeve is then tested to ensure that its performance meets design requirements and standards.

[0060] The preparation method described in this embodiment is convenient to operate. The resulting multi-layer rubber composite casing, designed to prevent casing deformation, effectively absorbs formation displacement and prevents casing deformation without affecting fracturing performance, thus improving the overall efficiency of shale oil and gas development. By designing multiple rubber layers with different expansion rates and arranging high-strength adhesive mesh material within the rubber layers, a perfect combination of expansibility and pressure resistance is achieved, solving the problem of insufficient pressure resistance after expansion in traditional casings, which leads to fluid leakage during fracturing. Simultaneously, the casing surface is coated with a waterproof material that dissolves at a certain temperature, effectively preventing premature expansion of the rubber layer before well entry, ensuring smooth operation. This design effectively absorbs formation displacement, prevents casing deformation, improves the casing's anti-deformation function and fracturing safety, significantly enhancing the overall efficiency of shale oil and gas development and possessing broad application prospects.

[0061] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0062] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0063] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0064] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0065] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0066] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A multi-layer rubber composite sleeve for preventing sleeve deformation, characterized in that, It includes a casing body and a rubber composite layer. The rubber composite layer is vulcanized and fixed on the outer wall of the casing body. The rubber composite layer includes multiple rubber layers stacked and fixed from the inside to the outside. The water absorption and expansion rate of the multiple rubber layers increases from the inside to the outside.

2. The multi-layer rubber composite sleeve for preventing sleeve deformation according to claim 1, characterized in that, The thickness of the multi-layer rubber layer gradually increases from the inside to the outside, and the thickness difference between two adjacent rubber layers is 1 to 2 mm; or, in the multi-layer rubber layer, the outermost rubber layer has the smallest thickness, and the thickness of the remaining rubber layers is equal.

3. The multi-layer rubber composite sleeve for preventing sleeve deformation according to claim 1, characterized in that, The rubber composite layer comprises 2 to 4 rubber layers.

4. The multi-layer rubber composite sleeve for preventing sleeve deformation according to claim 1, characterized in that, The total thickness of the rubber composite layer is 12-30 mm; in the multi-layer rubber layer, the thickness of the outermost rubber layer is 4-6 mm.

5. A multi-layer rubber composite sleeve for preventing sleeve deformation according to any one of claims 1 to 4, characterized in that, The rubber composite layer is embedded with multiple layers of adhesive-friendly mesh material, and the multiple layers of adhesive-friendly mesh material are evenly spaced in the rubber composite layer.

6. The multi-layer rubber composite sleeve for preventing sleeve deformation according to claim 5, characterized in that, The spacing between two adjacent layers of adhesive mesh material is 2-3 mm; the adhesive mesh material layer is a curtain fabric with a thickness of 0.5-1 mm and a mesh count of 40-100.

7. The multi-layer rubber composite sleeve for preventing sleeve deformation according to claim 5, characterized in that, The rubber composite layer is provided with multiple sets of countersunk holes arranged in a ring along the outer periphery of the casing body. The countersunk holes are arranged through multiple rubber layers and multiple layers of adhesive mesh material.

8. The multi-layer rubber composite sleeve for preventing sleeve deformation according to claim 7, characterized in that, The diameter of the countersunk hole is 10-20 mm, the ring spacing of multiple sets of countersunk holes is 50-100 mm, and the number of countersunk holes in each set is 30-40.

9. The multi-layer rubber composite sleeve for preventing sleeve deformation according to claim 1, characterized in that, A waterproof layer is also provided on the outer wall of the rubber composite layer, and the thickness of the waterproof layer is 1 to 3 mm.

10. A method for preparing a multi-layer rubber composite sleeve for preventing sleeve deformation according to any one of claims 6 to 9, characterized in that, Includes the following steps: S1, perform surface pretreatment on the surface of the casing body; S2, multiple rubber layers are wrapped around the surface of the casing body, and adhesive mesh material layers are arranged at intervals. Adhesive is placed between the adhesive mesh material layers and the rubber layers, and between the rubber layers and the casing body. S3, vulcanize the multi-layer rubber layer to ensure a strong bond between the rubber layer and the casing body, between adjacent rubber layers, and between the rubber layer and the adhesive mesh material layer. S4. After the entire rubber composite layer has been vulcanized, a perforation operation is performed on the outer surface of the rubber composite layer. S5. After drilling, a waterproof material is evenly sprayed onto the outer surface of the rubber composite layer to obtain a multi-layer rubber composite sleeve.

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