Breakage-proof and high-pressure-proof ground drilling well protection pipe for mining area

Abstract

The invention relates to the technical field of well drilling and protecting pipes, and discloses a mining area anti-breakage and anti-high-pressure ground well drilling and protecting pipe which comprises a plurality of protecting pipe sleeves, the top wall of each protecting pipe sleeve is provided with a limiting groove, the bottom wall of each protecting pipe sleeve is fixedly connected with a limiting rubber ring and a reinforcing sleeve, and the protecting pipe sleeves are connected through the reinforcing sleeves. The reinforcing sleeve is fixedly wrapped outside the protective pipe sleeve, a plurality of circular holes and strip-shaped holes are formed in the outer wall of the protective pipe sleeve, the well protection pipes are inserted into the protective pipe sleeve, each well protection pipe is formed by combining a supporting pipe, two coil pipes and a sealing sleeve, the two ends of each coil pipe are fixedly connected with the supporting pipes, and the supporting pipes are fixedly connected through the sealing sleeves. The technical means that the sectional type protective pipe sleeve is matched with the split type reinforcing sleeve is adopted, stratum displacement is adapted through sectional splicing, the reinforcing sleeve is radially hooped to reinforce the overall stability, and then the technical effects that deformation adaptability and structural pressure resistance are both considered, and the overall stability of the device is improved are achieved.

Description

Technical Field

[0001] This invention relates to the field of drilling well protection pipe technology, specifically a surface drilling well protection pipe for mining areas that is designed to prevent breakage and high pressure. Background Technology

[0002] Generally, from the perspective of coalfield geology, strata can be divided into three parts: loose strata, bedrock strata, and coal-bearing strata. In some mining areas, the loose strata can reach 300-600m. When using surface drilling to extract coalbed methane in mining-affected areas, the wells are easily damaged due to mining activities, which can seriously affect the extraction time and total extraction volume. Under the influence of mining activities such as caving, delamination, and surface subsidence, surface drilling in mining-affected areas may be damaged in multiple locations by shearing, tension, bending, etc., causing the surface drilling to be broken and flattened, thus seriously affecting the extraction time and total extraction volume.

[0003] Currently, surface drilling in mining areas uses the method of strengthening the well casing to resist the reduction or even breakage of the cross section caused by inconsistent rock displacement at the junction of loose layer and bedrock layer. Although this method is simple and direct, it is not very effective because the rock displacement force is too large.

[0004] In actual drilling, at the junction of loose layer and bedrock layer, due to surface subsidence, the displacement near the surface is much greater than the displacement at the lower boundary of loose layer. This causes the surface well to bend, and the cross-section of the well to be reduced by compression. In severe cases, it may even break. At this time, the well casing inside the well will also bend, losing its support and protection for the well. Summary of the Invention

[0005] This invention provides a well casing for surface drilling in mining areas to prevent breakage and high pressure, thereby solving the problem mentioned in the background art where, due to surface subsidence, the displacement near the surface is much greater than the displacement at the lower boundary of the loose layer, causing the surface drilling to bend and the well casing to bend accordingly, thus losing its protection for the drilling.

[0006] This invention provides a protective casing for surface drilling in mining areas to prevent breakage and high pressure, including a protective casing. Multiple protective casings are provided, and each protective casing has a limit groove on its top wall. A limit rubber ring is fixedly connected to the bottom wall of the protective casing, and the limit groove and the limit rubber ring are mutually engaged and adapted. The reinforcing sleeve and the protective sleeve are connected to each other by the reinforcing sleeve. The reinforcing sleeve is fixedly covered on the outside of the protective sleeve. The outer wall of the protective sleeve has multiple circular holes and strip holes. The well casing is provided in multiple parts and is inserted into the protective sleeve. Each well casing is composed of a support pipe, two coiled tubes and a sealing sleeve. The two ends of the coiled tubes are fixedly connected to the support pipes, and the support pipes are fixedly connected to each other by the sealing sleeve. The coiled tubes are provided with a transition rounded corner at the joint of the ring.

[0007] Preferably, the length of the limiting rubber ring is greater than the depth of the limiting groove, and the greater distance is 10-15 mm.

[0008] Preferably, the inner diameter of the circular holes is set to 8-12 mm, the circular holes are evenly distributed along the circumference of the sleeve, and 6-8 circular holes are provided in each ring 102. The axial distance between the circular holes and the strip holes is set to 20-30 mm.

[0009] Preferably, the length of the strip hole is set to 50-80 mm and the width is set to 8 mm. The strip holes are evenly distributed along the circumference of the sleeve, and there are 4-6 strip holes in each ring.

[0010] Preferably, both ends of the protective sleeve are fixedly connected with annular bosses, the inner diameter of which is 5-8 mm larger than the maximum outer diameter of the well casing, forming a radial gap.

[0011] Preferably, a wear-resistant rubber pad is attached to the inner side of the annular boss, and the surface of the rubber pad is treated with an anti-slip texture.

[0012] Preferably, a filter mesh sleeve and a reinforcing ring are fitted outside the protective sleeve, and the filter mesh sleeve is fixedly connected to the outside of the protective sleeve by the reinforcing ring.

[0013] Preferably, the transition radius of the serpentine tube is set to R3-R5 mm to avoid stress concentration caused by right angles or acute angles.

[0014] Preferably, the well casing adopts a multi-layer composite structure, which is composed of a thin pipe, a stainless steel braided mesh and a wear-resistant sheath. The stainless steel braided mesh is fixedly connected to the outer wall of the stainless steel braided mesh, and the wear-resistant sheath is fixedly connected to the outside of the stainless steel braided mesh.

[0015] Preferably, the stainless steel woven mesh has a weaving density of ≥80%, and the wear-resistant sheath is made of flexible material.

[0016] Compared with the prior art, the beneficial effects of the present invention are: This invention employs a combination of segmented protective sleeves and detachable reinforcing sleeves. By segmenting and splicing to adapt to minor ground displacements, the reinforcing sleeve is radially tightened to enhance overall stability. This overcomes the shortcomings of existing integrated protective sleeves, which are difficult to adapt to ground misalignment and have weak overall high-pressure resistance. Thus, it achieves the technical effect of balancing deformation adaptability and structural compressive strength, and improving the overall stability of the device.

[0017] This invention employs a combination of a flexible coiled tube structure and rounded transition corners. By utilizing the principle of absorbing formation stress through the bending and stretching of the coiled tube and eliminating stress concentration points through the rounded transition corners, it overcomes the shortcomings of existing rigid well casings that are prone to breakage due to stress concentration caused by formation deformation in mining areas. This achieves the technical effect of flexibly adapting to deformation in complex formations and significantly improving fracture resistance.

[0018] This invention employs a combination of a filter mesh sleeve and a reinforcing ring. The filter mesh sleeve intercepts sand and rock fragments to prevent gap blockage and pipe wear. This overcomes the shortcomings of existing technologies, such as the easy blockage of pressure balance channels by drilling sand in mining areas, pipe wear, and insufficient extrusion resistance of the protective sleeve. As a result, this invention achieves the technical effects of ensuring continuous and effective pressure balance, reducing pipe wear, improving the high pressure and extrusion resistance of the protective sleeve, and adapting to complex sand layer environments.

[0019] This invention employs a combination of high-density stainless steel woven mesh and a flexible, wear-resistant sheath. The stainless steel woven mesh enhances the tensile and crack resistance of the thin pipe and disperses deformation stress, while the flexible, wear-resistant sheath resists the frictional impact of sand particles and adapts to structural deformation. This overcomes the shortcomings of existing well casings, which have weak tensile and tear resistance due to their single structure, are easily worn, and have insufficient deformation adaptability. As a result, this invention achieves the technical effects of strengthening the structural strength of the well casing, extending its wear-resistant service life, ensuring the coordinated stability of the multi-layer structure during deformation, and adapting to the complex wear and deformation conditions in mining areas. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the overall structure of the filter sand mesh sleeve installation according to the present invention; Figure 3 This is a schematic diagram of the overall internal structure of the protective sleeve of the present invention; Figure 4 This is a schematic diagram of the disassembled structure of the protective sleeve of the present invention; Figure 5 This is a schematic diagram of the overall structure of the well casing of the present invention; Figure 6 This is a schematic diagram of the bending structure of the well casing of the present invention; Figure 7 This is a schematic diagram of the internal cross-sectional structure of the well casing of the present invention.

[0021] In the diagram: 100, protective sleeve; 101, reinforcing sleeve; 102, circular hole; 103, strip hole; 104, annular boss; 110, limiting groove; 120, limiting rubber ring; 200, well casing; 210, support pipe; 220, serpentine tube; 230, sealing sleeve; 201, thin tube; 202, stainless steel braided mesh; 203, wear-resistant sheath; 300, filter sand mesh sleeve; 301, reinforcing ring. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] This invention discloses a well casing for surface drilling in mining areas that is resistant to breakage and high pressure, such as... Figure 1-7 As shown, it includes a protective sleeve 100, and multiple protective sleeves 100 are provided. Each protective sleeve 100 has a limit groove 110 on its top wall and a limit rubber ring 120 is fixedly connected to its bottom wall. The limit groove 110 and the limit rubber ring 120 are mutually engaged and adapted to each other. It should be noted that the reinforcing sleeve 101 and the protective sleeve 100 are connected to each other through the reinforcing sleeve 101. The reinforcing sleeve 101 is fixedly covered on the outside of the protective sleeve 100. The outer wall of the protective sleeve 100 is provided with a plurality of circular holes 102 and strip holes 103. It should be noted that there are multiple well protection pipes 200. The well protection pipes 200 are inserted into the protective sleeve 100. Each well protection pipe 200 is composed of a support pipe 210, two snake pipes 220 and a sealing sleeve 230. The support pipes 210 are fixedly connected to both ends of the snake pipes 220. The support pipes 210 are fixedly connected to each other through the sealing sleeve 230. The snake pipes 220 have a transition rounded corner at the ring splice.

[0024] The working principle of the above technical solution is as follows: During use, multiple protective sleeves 100 are axially spliced ​​through a locking structure where limiting grooves 110 and limiting rubber rings 120 cooperate with each other. The limiting rubber rings 120 not only ensure the precise positioning of adjacent protective sleeves 100, but also compensate for minor displacements through their own elasticity, initially blocking the leakage channels of high-pressure media (such as gas and groundwater) in the well. The externally wrapped reinforcing sleeve 101 forms a radial clamping force on the spliced ​​protective sleeve group 100, strengthening the overall structural stability and preventing separation at the segmented connection due to high pressure. The well protection pipe 200 adopts a combination structure of support pipe 210 and snake pipe 220. Support pipe 210 provides basic bearing capacity, while snake pipe 220 utilizes the flexible characteristics of its corrugated structure to adapt to the settlement and displacement deformation of the strata in the mining area. When the strata move slightly, snake pipe 220 can absorb deformation stress through its own bending and expansion, avoiding the traditional rigidity. The well casing 200 fractured due to stress concentration. Meanwhile, the rounded transition at the joint of the coiled tubing 220 further reduces stress concentration points and improves deformation resistance. The circular holes 102 and strip holes 103 on the outer wall of the protective sleeve 100 achieve pressure balance between the well casing 200 and the formation. When high pressure occurs in the well, some media can permeate through the channels into the gap between the formation and the protective sleeve 100, reducing the pressure load on the inner wall of the well casing 200. Simultaneously, the channels prevent the formation from generating suction force due to negative pressure between the formation and the protective sleeve 100, reducing the additional force exerted on the well casing 200 by formation deformation. The support pipes 210 are fixedly connected by sealing sleeves 230, forming a double sealing system with the limiting rubber ring 120. This effectively prevents high-pressure media from leaking through the joint gaps, ensuring the sealing reliability of the well casing 200 under high-pressure conditions and preventing safety hazards caused by leaks of gas, groundwater, or other media.

[0025] This invention employs a combination of segmented protective sleeve 100 and split reinforcing sleeve 101. By segmenting and splicing to adapt to minor ground displacements, the reinforcing sleeve 101 is radially tightened to enhance overall stability. This overcomes the shortcomings of existing integrated protective sleeves, which are difficult to adapt to ground misalignment and have weak overall high-pressure resistance. Thus, it achieves the technical effect of balancing deformation adaptability and structural pressure resistance, and improving the overall stability of the device.

[0026] This invention employs a flexible structure of the 220-type coiled tubing combined with rounded transition corners. By utilizing the principle of the 220-type coiled tubing's bending and stretching to absorb formation stress and the rounded transition corners to eliminate stress concentration points, it overcomes the shortcomings of the existing rigid well casing 200, which is prone to stress concentration and breakage due to formation deformation in mining areas. This achieves the technical effect of flexibly adapting to deformation in complex formations and significantly improving fracture resistance.

[0027] In one specific embodiment: the length of the limiting rubber ring 120 is greater than the depth of the limiting groove 110, and the greater distance is 10-15 mm.

[0028] Furthermore, the interference fit design, where the length of the limiting rubber ring 120 is greater than the depth of the limiting groove 110, ensures that the rubber ring is always in a compressed state after being engaged. This not only fills the splice gap through elastic deformation to achieve high-pressure sealing, but also uses the extra length to compensate for minor axial displacements (such as settlement and tension) in the strata of the mining area, preventing leakage caused by gaps at the splice due to displacement. At the same time, the compressed limiting rubber ring 120 generates a continuous radial preload, further improving the overall integrity of the protective sleeve 100 after splicing.

[0029] Furthermore, this invention employs a technique where a limiting rubber ring 120 with an extended length of the limiting groove 110 is matched with a segmented protective sleeve 100. By utilizing the interference compression of the limiting rubber ring 120 to achieve sealing and compensate for axial displacement with excess length, this invention overcomes the shortcomings of existing well casing 200 where the seal at the joint is prone to failure and cannot adapt to minor axial deformation of the formation. As a result, it achieves the technical effect of reliable sealing under high pressure conditions and stable response to formation subsidence and tension.

[0030] It should be noted that the inner diameter of the circular hole 102 is set to 8-12 mm, the circular holes 102 are evenly distributed along the circumference of the sleeve, and there are 6-8 circular holes 102 in each ring. The axial distance between the circular holes 102 and the strip holes 103 is set to 20-30 mm.

[0031] It should be noted that the length of the strip hole 103 is set to 50-80 mm and the width is set to 8 mm. The strip holes 103 are evenly distributed along the circumference of the sleeve, and there are 4-6 strip holes 103 in each circle.

[0032] Furthermore, the circular holes 102 and strip holes 103 on the protective sleeve 100 form a multi-point dispersion and complementary long and short holes pressure balance system. The circular holes 102 enable rapid penetration and pressure relief of high-pressure media, while the strip holes 103 expand the medium flow area to adapt to the pressure relief requirements under different pressure conditions. The evenly distributed holes ensure circumferential pressure balance of the pipe body and avoid local pressure concentration that could lead to pipe deformation. At the same time, the connection between the holes and the formation gap eliminates the negative pressure adsorption force between the pipe body and the formation.

[0033] Furthermore, the present invention employs a technical means of combining circular holes 102 and strip holes 103 with a specific size distribution. The circular holes 102 quickly relieve pressure, while the strip holes 103 expand the flow area. This overcomes the shortcomings of the existing well casing 200, such as poor pressure balance and easy deformation due to local pressure concentration. In this way, the technical effect of accurately balancing the pressure between the casing and the formation is achieved, and the damage of the casing due to local overload is avoided.

[0034] In addition, both ends of the protective sleeve 100 are fixedly connected with annular bosses 104. The inner diameter of the annular bosses 104 is 5-8 mm larger than the maximum outer diameter of the well casing 200, forming a radial gap.

[0035] Specifically, a wear-resistant rubber pad is attached to the inner side of the annular boss 104, and the surface of the rubber pad is treated with an anti-slip texture.

[0036] Furthermore, the annular bosses 104 at both ends of the inner casing 100 form a precise radial gap, which not only provides radial positioning for the well casing 200 to prevent it from shifting significantly downhole, but also reserves space for radial displacement of the well casing 200 due to formation deformation. The anti-slip and wear-resistant rubber pads pasted on the inner side of the annular bosses 104 restrict the circumferential rotation of the well casing 200 through anti-slip texture, but also use the elasticity of the rubber to buffer the force of well wall vibration or formation impact on the well casing 200, while reducing friction and wear between the well casing 200 and the annular bosses 104, thus extending the service life of the device.

[0037] Furthermore, the present invention employs a technical means of combining an annular boss 104 with an anti-slip and wear-resistant rubber pad. By utilizing the radial limiting of the annular boss 104 and the elastic buffering and anti-slip of the rubber pad, the shortcomings of the existing well casing 200, such as easy radial displacement, circumferential rotation, and severe friction and wear with the protective sleeve 100, are overcome. This achieves the technical effects of precise positioning of the well casing 200, reduced wear, and extended service life of the device.

[0038] It should be noted that the transition radius of the 220 coiled tube is set to R3-R5 mm to avoid stress concentration caused by right angles or sharp angles.

[0039] Furthermore, the 220 coil adopts a rounded corner design to completely replace the right-angle or acute-angle structure, making the stress distribution at the splice of the 220 coil more uniform. When the stratum deformation causes the 220 coil to bend or expand, the rounded corner structure will disperse the concentrated stress to a larger area, avoiding local stress exceeding the material yield strength and causing cracking. At the same time, the flexible structure of the 220 coil, combined with the precise rounded corner parameters, ensures that it can still maintain structural integrity within the deformation range, effectively adapting to the complex displacement of the stratum in the mining area.

[0040] Furthermore, this invention employs a technical means of combining the serpentine tube 220 with the support tube 210, utilizing the flexible deformation of the serpentine tube 220 to adapt to formation displacement, overcoming the shortcomings of the existing well casing 200 and serpentine tube 220 splicing joints being prone to cracking due to sharp angle stress concentration and having weak deformation resistance, thereby achieving the technical effect of significantly improving the crack resistance performance of the well casing 200 and stably adapting to the complex formation deformation in the mining area.

[0041] In one specific embodiment: a filter mesh sleeve 300 and a reinforcing ring 301 are fitted on the outside of the protective sleeve 100, and the filter mesh sleeve 300 is fixedly connected to the outside of the protective sleeve 100 through the reinforcing ring 301.

[0042] The working principle of the above technical solution is as follows: During use, the filter sand mesh sleeve 300 is wrapped around the outside of the protective sleeve 100. With the filtering characteristics of its mesh structure, it can intercept solid impurities such as sand particles and rock cuttings generated by the collapse of the drilling well wall, and prevent impurities from entering the gap between the protective sleeve 100 and the well casing 200 through the circular holes 102 and strip holes 103 of the protective sleeve 100. This prevents the gap from being blocked and causing the pressure balance function to fail. At the same time, it prevents impurities from wearing down the outer wall of the well casing 200 and the rubber pad of the annular boss 104. The cooperation between the filter sand mesh sleeve 300 and the reinforcing ring 301 not only solves the problems of impurity blockage and wear, but also enhances the structural stability of the protective sleeve 100, and further optimizes the applicability of the device in the complex sand layer environment of the mining area.

[0043] This invention employs a combination of a filter mesh sleeve 300 and a reinforcing ring 301. The filter mesh sleeve 300 intercepts sand and rock fragments to prevent gap blockage and pipe wear. This overcomes the shortcomings of existing technologies, such as drilling sand in mining areas easily clogging pressure balance channels, wearing pipes, and insufficient extrusion resistance of the protective sleeve 100. As a result, this invention achieves the technical effects of ensuring continuous and effective pressure balance, reducing pipe wear, improving the high pressure and extrusion resistance of the protective sleeve 100, and adapting to complex sand layer environments.

[0044] In one specific embodiment: the well casing 200 adopts a multi-layer composite structure. The well casing 200 is composed of a thin tube 201, a stainless steel braided mesh 202 and a wear-resistant sheath 203. The stainless steel braided mesh 202 is fixedly connected to the outer wall of the stainless steel braided mesh 202, and the wear-resistant sheath 203 is fixedly connected to the outside of the stainless steel braided mesh 202.

[0045] The stainless steel woven mesh 202 has a weaving density of ≥80%, and the wear-resistant sheath 203 is made of flexible material.

[0046] The working principle of the above technical solution is as follows: During use, the invention utilizes a multi-layer composite structure of the well casing 200, consisting of a thin tube 201, a stainless steel braided mesh 202, and a wear-resistant sheath 203. This structure provides a synergistic effect of basic load-bearing, flexible reinforcement, and wear-resistant protection. The thin tube 201, as the inner basic structure of the well casing 200, directly serves as the channel for transporting drilling media. Its rigidity ensures the stability of the core channel of the well casing 200, preventing channel collapse or deformation due to external stress. This provides a foundation for the installation and support of the subsequent multi-layer structure. The stainless steel braided mesh 202 is fixed to the outer wall of the thin tube 201. The high-density braided structure retains the tensile strength of the metal material while also possessing a certain degree of flexible deformation capability. When formation deformation causes the well casing 200 to bend or stretch, the stainless steel braided mesh 202 can disperse stress through the slight displacement of its fibers, preventing the thin tube 201 from being damaged by localized stress. Stress concentration leads to cracks, while simultaneously enhancing the overall tensile and tear resistance of the well casing 200, compensating for the weak deformation resistance of the single thin tube 201. The outer flexible wear-resistant sheath 203 tightly wraps around the stainless steel woven mesh 202, and its wear-resistant properties can directly resist the friction and impact of sand and rock cuttings in the well, as well as the scraping of the well wall rocks, extending the overall service life of the well casing 200. At the same time, the flexible material can expand and contract synchronously with the deformation of the well casing 200, without affecting the stress dispersion function of the stainless steel woven mesh 202, ensuring that the multi-layer structure always fits during deformation and works together to provide protection. The multi-layer composite structure of the well casing 200, through the complementary functions of each layer, not only maintains the stability of the basic channel, but also enhances the deformation and wear resistance, and is compatible with the overall anti-breakage and anti-high pressure mechanism of the device, further improving the reliability of the well casing 200 under complex working conditions in the mining area.

[0047] This invention employs a combination of high-density stainless steel woven mesh 202 and a flexible wear-resistant sheath 203. The stainless steel woven mesh 202 enhances the tensile and crack resistance of the thin tube 201 and disperses deformation stress, while the flexible wear-resistant sheath 203 resists the frictional impact of sand particles and adapts to structural deformation. This overcomes the shortcomings of existing well casing 200, which has weak tensile and tear resistance due to its single structure, is easily worn, and has insufficient deformation adaptability. As a result, this invention achieves the technical effects of strengthening the structural strength of the well casing 200, extending its wear-resistant service life, ensuring the coordinated stability of the multi-layer structure during deformation, and adapting to the complex wear and deformation conditions in mining areas.

[0048] The contents not described in detail in this description are existing technologies known to those skilled in the art. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A well casing for surface drilling in mining areas to prevent breakage and high pressure, characterized in that, include A protective sleeve (100) is provided in multiple ways. Each protective sleeve (100) has a limiting groove (110) on its top wall and a limiting rubber ring (120) fixedly connected to its bottom wall. The limiting groove (110) and the limiting rubber ring (120) are mutually engaged and adapted to each other. The reinforcing sleeve (101) is used to connect the protective sleeves (100) to each other. The reinforcing sleeve (101) is fixedly covered on the outside of the protective sleeve (100). The outer wall of the protective sleeve (100) is provided with a plurality of circular holes (102) and strip holes (103). A well protection pipe (200) is provided in multiple ways. The well protection pipe (200) is inserted into the protective sleeve (100). Each well protection pipe (200) is composed of a support pipe (210), two snake pipes (220) and a sealing sleeve (230). The two ends of the snake pipe (220) are fixedly connected to the support pipe (210). The support pipes (210) are fixedly connected to each other through the sealing sleeve (230). The snake pipe (220) is provided with a transition rounded corner at the ring splice.

2. The wellbore casing of claim 1, wherein, The length of the limiting rubber ring (120) is greater than the depth of the limiting groove (110), and the greater distance is 10-15 mm.

3. The wellbore casing of claim 1, wherein, The inner diameter of the circular hole (102) is set to 8-12 mm. The circular holes (102) are evenly distributed along the circumference of the sleeve. There are 6-8 circular holes (102) in each circle. The axial distance between the circular holes (102) and the strip holes (103) is set to 20-30 mm.

4. The wellbore casing of claim 1, wherein, The length of the strip hole (103) is set to 50-80 mm and the width is set to 8 mm. The strip hole (103) is evenly distributed along the circumference of the sleeve, and there are 4-6 strip holes (103) in each circle.

5. The wellbore casing of claim 1, wherein, Both ends of the protective sleeve (100) are fixedly connected with annular bosses (104). The inner diameter of the annular bosses (104) is 5-8 mm larger than the maximum outer diameter of the well protection pipe (200), forming a radial gap.

6. The wellbore casing of claim 5, wherein, The inner side of the annular boss (104) is covered with a wear-resistant rubber pad, and the surface of the rubber pad is treated with an anti-slip texture.

7. The wellbore casing of claim 1, wherein, The protective sleeve (100) is fitted with a filter mesh sleeve (300) and a reinforcing ring (301) on the outside. The filter mesh sleeve (300) is fixedly connected to the outside of the protective sleeve (100) through the reinforcing ring (301).

8. The wellbore casing of claim 1, wherein, The transition radius of the serpentine tube (220) is set to R3-R5 mm to avoid stress concentration caused by right angles or acute angles.

9. The wellbore casing of claim 1, wherein, The well casing (200) adopts a multi-layer composite structure. The well casing (200) is composed of a thin tube (201), a stainless steel woven mesh (202) and a wear-resistant sheath (203). The stainless steel woven mesh (202) is fixedly connected to the outer wall of the stainless steel woven mesh (202), and the wear-resistant sheath (203) is fixedly connected to the outside of the stainless steel woven mesh (202).

10. The wellbore casing of claim 9, wherein, The stainless steel woven mesh (202) has a weaving density of ≥80%, and the wear-resistant sheath (203) is made of flexible material.

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