Natural gas hydrate multilateral well connecting section well wall stabilizing device and damage repairing method

Abstract

The invention discloses a natural gas hydrate multilateral well connection section well wall stabilizing device which comprises a main body adjusting assembly, a main body assembly, a rotating mechanism, a damage detecting and positioning assembly and a drilling and grouting assembly, the main body adjusting assembly is connected with the main body assembly, and the main body assembly and the damage detecting and positioning assembly are connected with the rotating mechanism. The main body assembly and the damage detecting and positioning assembly can rotate independently, the drilling and grouting assembly is arranged at the top of the main body assembly, the damage detecting and positioning assembly can detect and position the damaged position of the inner wall of the natural gas hydrate well, and the drilling and grouting assembly can repair the damaged position through drilling and grouting. The all-angle damage detection and directional grouting integrated function of the connection section of the natural gas hydrate multilateral well can be achieved, the repairing time and cost are reduced, the well wall stability is greatly improved, and safe and efficient exploitation of the natural gas hydrate is guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of petroleum engineering, and in particular to a well wall stabilizing device for a natural gas hydrate branch well connection section and a damage repair method. Background Art

[0002] The gas hydrate reservoir has the characteristics of weak glue, low strength and easy sand production, especially the branch well connection section is prone to well wall damage, inducing well wall instability. If not treated in time, it will threaten the safety and stability of the gas hydrate production layer, which has become a key issue restricting the safe and efficient exploitation of gas hydrates. Conventional well wall grouting equipment has only a single limited function, and the steps are cumbersome and the plugging effect is poor. It is not very suitable for the repair of deepwater gas hydrate well walls.

[0003] Therefore, there is an urgent need for a natural gas hydrate branch well connection section stabilizing well wall device. Summary of the invention

[0004] On one hand, the present invention provides a natural gas hydrate branch well connection section stabilizing well wall device to solve the problem that the traditional well wall damage repair requires two independent procedures of well wall detection and grouting repair, which is cumbersome in operation steps and poor in repair effect. On the second hand, the present invention provides a method for repairing the well wall of the connection section of a natural gas hydrate branch well using the natural gas hydrate branch well connection section stabilizing well wall device.

[0005] The first aspect of the present invention provides a natural gas hydrate branch well connection section stabilizing well wall device, comprising a main body adjustment component, a main body component, a rotating mechanism, a damage detection and positioning component and a drilling and grouting component, wherein the main body adjustment component is connected to the main body component, and the main body component and the damage detection and positioning component are respectively connected to the rotating mechanism to enable the main body component and the damage detection and positioning component to rotate separately, and the drilling and grouting component is arranged on the top of the main body component, and the damage detection and positioning component can detect and locate the damaged part of the inner wall of the natural gas hydrate well, and the drilling and grouting component realizes the repair of the damaged part by drilling and grouting.

[0006] The natural gas hydrate branch well connecting section well wall stabilization device, preferably, the main body component includes a main body base and a main body top cover, the main body top cover is connected to the main body adjustment component, the rotating mechanism is provided between the main body base and the main body top cover, and the damage detection and positioning component is located between the main body base and the main body top cover.

[0007] The natural gas hydrate branch well connecting section stabilizing well wall device, preferably, the damage detection and positioning assembly includes a plurality of annular support frames, positioning components, ranging sensors and propping assemblies, the positioning assemblies and the ranging sensors are distributed on the outer circumference of the annular support frames, and the inner cavity of each of the annular support frames is provided with the propping assembly.

[0008] The natural gas hydrate branch well connecting section well wall stabilizing device, preferably, the propping assembly includes a fixed frame, a bracket, a transverse driving member and a plurality of oblique driving members, the bracket is provided on the fixed frame, the transverse driving member is provided on the bracket, and the transverse driving member is connected to the annular support frame through the oblique driving member.

[0009] The device for stabilizing the well wall of the natural gas hydrate branch well connection section, preferably, the transverse driving member includes a rotating shaft, a first rotating arm, a second rotating arm, a first planetary gear, a second planetary gear, an inner gear ring, a first guide rod, a second guide rod, a first slide rail, a second slide rail, a first slider, a second slider, a first worm, a second worm, a bevel gear and a trapezoidal bracket, the first planetary gear and the second planetary gear are respectively meshed with the inner gear ring, the first slider is arranged on the first slide rail and the first slider is provided with the first worm, the second slider is arranged on the second slide rail and the second slider is provided with the second worm, the two ends of the first rotating arm are respectively connected to the rotating shaft and the first planetary gear, the two ends of the second rotating arm are respectively connected to the rotating shaft and the second planetary gear, one end of the first guide rod is rotatably connected to the first planetary gear, the other end of the first guide rod is connected to the first slider, one end of the second guide rod is rotatably connected to the second planetary gear, the other end of the second guide rod is connected to the second slider, the end of the first worm and the end of the second worm are respectively provided with the bevel gear, and the bevel gear is connected to the oblique driving member through the trapezoidal bracket.

[0010] The natural gas hydrate branch well connecting section well wall stabilizing device, preferably, the oblique driving member includes a connecting rod, a spring and a hinged rod, one end of the connecting rod is connected to the trapezoidal bracket, the connecting rod is a cavity structure, the spring is arranged in the cavity of the connecting rod, and one end of the spring is fixed to the inner cavity of the connecting rod, the other end of the spring is connected to the hinged rod, and the hinged rod is connected to the annular support frame.

[0011] The natural gas hydrate branch well connecting section stabilizing well wall device, preferably, the positioning component includes a camera, a distance calibrator and an LED light strip, the camera is arranged on the outer periphery of the annular support frame, the LED light strip is arranged around the camera, and the distance calibrator is arranged on the camera.

[0012] The natural gas hydrate branch well connecting section well wall stabilizing device, preferably, the drilling grouting assembly includes a drill rod, a drill bit, a grouting component, a slurry pipe and a slurry tank, the slurry tank is arranged on the ground, the grouting component is connected to the slurry tank through the slurry pipe, and the grouting component is connected to the main body top cover through a fixing bolt, the drill rod is provided on the grouting component, and the drill bit is provided on the drill rod.

[0013] The natural gas hydrate branch well connection section stabilizing well wall device, preferably, the rotating mechanism includes a first rotating device and a second rotating device, the lower part of the main body top cover is connected to the first rotating device, the second rotating device is provided on the main body base, and the damage detection and positioning assembly is connected to the second rotating device.

[0014] The natural gas hydrate branch well connection section well wall stabilization device, preferably, the main body adjustment assembly includes an insertion component and a main balance frame, the insertion component is connected to the main balance frame, and the insertion component is arranged on the main body top cover.

[0015] A second aspect of the present invention provides a method for repairing damage to the well wall of a natural gas hydrate branch well connection section by using a natural gas hydrate branch well connection section stabilizing well wall device, the method comprising the following steps: Clear the site, hoist the main assembly to the support plate on the ground in advance and connect the insertion parts and drilling and grouting components, conduct inspection and test run, and ensure that the main assembly is in place stably by adjusting the main balance frame. The main assembly and the center of the wellbore should be in a straight line; Use the damage detection and positioning components to inspect and locate the wellbore wall of the natural gas hydrate multi-branch well, control the speed of the main component entering the well, and ensure that the damage detection and positioning components meet the inspection specification requirements; Use the drilling grouting assembly to drill holes at damaged parts of the wellbore wall, control the drilling speed and hole size, and simultaneously use the damage detection and positioning assembly to inspect the hole to check the depth, diameter and inclination of the hole; Use drilling grouting components to inject slurry, control the injection depth and speed of the slurry, ensure continuous injection of the slurry, and ensure the quality of the well wall repair. After the slurry injection is completed, use the damage detection and positioning components to check the well wall after repair; The main components are lifted to complete the integrated process of natural gas hydrate branch well damage detection and directional grouting.

[0016] The beneficial effects are: Multiple annular support components are synchronously pushed to move radially through transverse driving components and oblique driving components, conforming to multi-scale well walls and suitable for multi-scale natural gas hydrate well diameters. It has strong applicability and can synchronously achieve effective deformation detection and positioning.

[0017] In this application, the integrated operation of well wall damage detection and directional grouting can be realized, multiple operation steps can be avoided, the repair efficiency can be greatly improved, the repair cost can be reduced, the stability of the natural gas hydrate well wall can be improved, and the safe and efficient exploitation of natural gas hydrate resources can be ensured. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the use state of the natural gas hydrate branch well connection section stabilizing well wall device of the present invention extending into the branch well; Figure 2 It is a schematic structural diagram of a well wall stabilizing device for a natural gas hydrate branch well connection section according to the present invention; Figure 3 A top view of the main assembly; Figure 4 A top view of the assembly positioned for damage detection; Figure 5 Schematic diagram of the internal structure of the lateral drive component.

[0019] In the figure: 1. Insertion component; 2. Drill bit; 3. Slurry pipe; 4. Grouting component; 5. First rotating device; 6. Second rotating device; 7. Positioning component; 8. Distance measuring sensor; 9. Main body base; 10. Slurry tank; 11. Limit plate; 12. Main body cover; 13. Camera; 14. Distance calibrator; 15. LED light strip; 16. annular support frame; 17. electromagnet; 18. bracket; 19. inner gear ring; 20. fixing frame; 21. Trapezoidal bracket; 22. Connecting rod; 23. Cavity; 24. Articulated rod; 25. Bevel gear; 26. First worm gear; 28. Fixing bolt; 29. Drill rod; 30. Main balance frame; 31. Rotating shaft; 32. First rotating arm; 33. Second rotating arm; 34. First planetary gear; 35. Second planetary gear; 36. Spring; 37. First guide rod; 38. second guide rod; 39. first slide rail; 40. second slide rail; 41. first slide block; 42. Second slider; 43. Second worm DETAILED DESCRIPTION In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0020] In the description of the present invention, it should be noted that the terms "top", "bottom", "one end" and "the other end" indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the system or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second" and the like are used to define components only for the convenience of distinguishing the above components. If not otherwise stated, the above terms have no special meanings and cannot be understood as indicating or implying relative importance.

[0021] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "disposed" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0022] The present invention provides a device for stabilizing the well wall of a natural gas hydrate branch well connection section, comprising a main body adjustment component, a main body component, a rotating mechanism, a damage detection and positioning component, and a drilling grouting component, wherein the main body adjustment component is connected to the main body component, the main body component is connected to the damage detection and positioning component through the rotating mechanism, the drilling grouting component is arranged on the top of the main body component, the damage detection and positioning component can detect and locate the damaged part of the inner wall of the natural gas hydrate well, and the drilling grouting component repairs the damaged part by drilling grouting. The present invention can realize the integrated operation of well wall damage detection and directional grouting, avoid multiple operation steps, greatly improve the repair efficiency, reduce the repair cost, improve the stability of the natural gas hydrate well wall, and ensure the safe and efficient exploitation of natural gas hydrate resources.

[0023] The entire technical process is described in detail below using a natural gas hydrate branch well connection section stabilizing wellbore device as an example.

[0024] Example 1 like Figures 1 to 5As shown, a wellbore stabilizing device for a natural gas hydrate branch well connection section includes a main body adjustment component, a main body component, a rotating mechanism, a damage detection and positioning component and a drilling and grouting component. The main body adjustment component is connected to the main body component, and the main body component and the damage detection and positioning component are respectively connected to the rotating mechanism to enable the main body component and the damage detection and positioning component to rotate separately, and the drilling and grouting component is arranged on the top of the main body component. The damage detection and positioning component can detect and locate the damaged part of the inner wall of the natural gas hydrate well, and the drilling and grouting component realizes the repair of the damaged part by drilling and grouting.

[0025] like Figure 2 As shown, the rotating mechanism includes a first rotating device 5 and a second rotating device 6. The lower part of the main body top cover 12 is connected to the first rotating device 5. The second rotating device 6 is provided on the main body base 9. The damage detection and positioning assembly is connected to the second rotating device 6.

[0026] When the ranging sensor 8 detects damage to the well wall, the first rotating device 5 will drive the rotation and displacement of the annular support frame 16, and accurately identify the positioning through the positioning component 7. The second rotating device 6 drives the drill bit 2 and the grouting component 4 on the main body top cover 12 to achieve 360° rotation and displacement grouting, completing the drilling and grouting repair of the damaged part of the well wall.

[0027] The main body adjustment assembly includes an extending component 1 and a main balancing frame 30 . The extending component 1 is connected to the main balancing frame 30 , and the extending component 1 is arranged on the main body top cover 12 .

[0028] The drilling grouting assembly includes a drill rod 29, a drill bit 2, a grouting component 4, a slurry pipe 3 and a slurry tank 10. The slurry tank 10 is set on the ground. The grouting component 4 is connected to the slurry tank 10 through the slurry pipe 3, and the grouting component 4 is connected to the main body top cover 12 through a fixing bolt 28. The grouting component 4 is provided with a drill rod 29, and the drill rod 29 is provided with a drill bit 2.

[0029] A limit plate 11 is provided on the drill rod 29 , and the limit plate 11 fixes the drill rod 29 and limits the displacement of the drill rod 29 .

[0030] like Figure 3 As shown, the main body component includes a main body base 9 and a main body top cover 12, the main body top cover 12 is connected to the main body adjustment component, the rotating mechanism is provided between the main body base 9 and the main body top cover 12, and the damage detection and positioning component is located between the main body base 9 and the main body top cover 12.

[0031] like Figure 4As shown, the damage detection and positioning assembly includes multiple annular support frames 16, positioning components 7, distance measuring sensors 8 and expansion assemblies. The positioning assemblies and distance measuring sensors 8 are distributed on the outer circumference of the annular support frames 16, and the inner cavity of each annular support frame 16 is provided with the expansion assembly.

[0032] There are four annular support frames 16 .

[0033] The expansion assembly includes a fixing frame 20, a bracket 18, a transverse driving member and a plurality of oblique driving members. The fixing frame 20 is provided with a bracket 18, and the bracket 18 is provided with the transverse driving member. The transverse driving member is connected to the annular support frame 16 through the oblique driving member. The fixing frame 20 is fixed by passing through the electromagnet 17.

[0034] Among them, the number of oblique driving members is 4.

[0035] like Figure 5 As shown, the transverse driving member includes a rotating shaft 31, a first rotating arm 31, a second rotating arm 33, a first planetary gear 34, a second planetary gear 35, an inner gear ring 19, a first guide rod 37, a second guide rod 38, a first slide rail 39, a second slide rail 40, a first slider 41, a second slider 42, a first worm 26, a second worm 43, a bevel gear 25 and a trapezoidal bracket 21, the first planetary gear 34 and the second planetary gear 35 are respectively meshed with the inner gear ring 19, the first slider 41 is arranged on the first slide rail 39 and the first slider 41 is provided with the first worm 26, the second slider 42 is arranged on the second slide rail 40 and the second slider 43 is provided with the first worm 26, A second worm 43 is provided on the block 42, two ends of the first rotating arm 31 are respectively connected to the rotating shaft 31 and the first planetary gear 34, two ends of the second rotating arm 33 are respectively connected to the rotating shaft 31 and the second planetary gear 35, one end of the first guide rod 37 is rotatably connected to the first planetary gear 34, the other end of the first guide rod 37 is connected to the first slider 41, one end of the second guide rod 38 is rotatably connected to the second planetary gear 35, the other end of the second guide rod 38 is connected to the second slider 42, the end of the first worm 26 and the end of the second worm 43 are respectively provided with a bevel gear 25, and the bevel gear 25 is connected to the oblique driving member through the trapezoidal bracket 21.

[0036] The oblique driving member includes a connecting rod 22, a spring 36 and a hinged rod 24. One end of the connecting rod 22 is connected to the trapezoidal bracket 21. The connecting rod 22 is a cavity 23 structure. The spring 36 is arranged in the cavity 23 of the connecting rod 22, and one end of the spring 36 is fixed to the inner cavity of the connecting rod 22. The other end of the spring 36 is connected to the hinged rod 24, and the hinged rod 24 is connected to the annular support frame 16.

[0037] The positioning component 7 includes a camera 13 , a distance calibrator 14 and an LED light strip 15 . The camera 13 is arranged on the outer periphery of the annular support frame 16 . The LED light strip 15 is arranged around the camera 13 . The distance calibrator 14 is arranged on the camera 13 .

[0038] Working process: The rotating shaft 31 drives the first rotating arm 32, and the first rotating arm 32 drives the first planetary gear 34 to move along the inner gear ring 19. The first planetary gear 34 drives the first guide rod 37 to move in the inner gear ring 19, so that the first guide rod 37 drives the first slider 41 to move on the first slide rail 39, so that the first slider 41 drives the first worm 26 to extend, that is, the first worm 26 rotates synchronously to drive the bevel gear 25 on the first worm 26 to move horizontally; The rotating shaft 31 drives the second rotating arm 33, and the second rotating arm 33 drives the second planetary gear 35 to move along the inner gear ring 19. The second planetary gear 35 drives the second guide rod 38 to move in the inner gear ring 19, so that the second guide rod 38 drives the second slider 42 to move on the second slide rail 40, so that the second slider 42 drives the second worm 43 to extend, that is, the second worm 43 rotates synchronously to drive the bevel gear 25 on the second worm 43 to move horizontally; The first worm 26 and the second worm 43 are connected to each connecting rod 22 through the bevel gear 25 and the trapezoidal bracket 21. Each connecting rod 22 moves radially, and each driving hinge rod 24 fits the outer end surface of the annular support frame 16 to the well wall. It is suitable for multi-scale well diameters of natural gas hydrates. The positioning component 7 and the distance sensor 8 on the annular support frame 16 are used for damage detection and positioning of the natural gas hydrate branch well wall. The damaged part is drilled through the hole component on the main top cover 12, and the slurry is pumped to the damaged part by the grouting component 4. At the same time, the positioning component 7 is used again for acceptance inspection. The first rotating device 5 and the second rotating device 6 are set between the main base 9, the annular support frame 16 and the main top cover 12, which can realize 360° rotation and displacement in the well, and carry out damage detection and directional grouting integration functions at all angles, greatly saving the well repair time, reducing the repair cost, improving the well wall stability, and ensuring the safe and efficient exploitation of natural gas hydrate resources.

[0039] Example 2 A method for repairing the damage of the well wall of the connection section of a natural gas hydrate branch well by using a well wall stabilizing device for the connection section of a natural gas hydrate branch well, the method comprising the following steps: S1: Clear the site, hoist the main assembly to the support plate on the ground in advance and connect the insertion parts and drilling and grouting components, conduct inspection and test run, and ensure that the main assembly is in place stably by adjusting the main balance frame. The main assembly and the center of the wellbore should be in a straight line; S2: Use the damage detection and positioning components to inspect and locate the wellbore wall of the natural gas hydrate multi-branch well, control the speed of the main component entering the well, and ensure that the damage detection and positioning components meet the inspection specification requirements; S3: Use the drilling grouting assembly to drill holes at the damaged part of the well wall, control the drilling speed and the size of the hole, and simultaneously use the damage detection and positioning assembly to check the hole depth, diameter and inclination; S4: Use the drilling grouting assembly to inject the slurry, control the injection depth and speed of the slurry, ensure the continuous injection of the slurry, and ensure the quality of the well wall repair. After the slurry injection is completed, use the damage detection and positioning assembly to check the well wall after repair; S5: Lift the main assembly and complete the integrated process of natural gas hydrate branch well damage detection and directional grouting.

[0040] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A natural gas hydrate branch well connection section stabilizing well wall device, characterized in that: The invention comprises a main body adjustment component, a main body component, a rotating mechanism, a damage detection and positioning component and a drilling and grouting component, wherein the main body adjustment component is connected to the main body component, and the main body component and the damage detection and positioning component are respectively connected to the rotating mechanism so that the main body component and the damage detection and positioning component can rotate separately and separately, and the drilling and grouting component is arranged on the top of the main body component, and the damage detection and positioning component can detect and locate the damaged part of the inner wall of the natural gas hydrate well, and the drilling and grouting component realizes the repair of the damaged part by drilling and grouting.

2. The natural gas hydrate branch well connection section stabilizing well wall device according to claim 1, characterized in that: The main body component includes a main body base and a main body top cover, the main body top cover is connected to the main body adjustment component, the rotating mechanism is provided between the main body base and the main body top cover, and the damage detection and positioning component is located between the main body base and the main body top cover.

3. The natural gas hydrate branch well connection section stabilizing well wall device according to claim 2, characterized in that: The damage detection and positioning assembly includes a plurality of annular support frames, positioning components, distance measuring sensors and expansion assemblies. The positioning assemblies and the distance measuring sensors are distributed on the outer circumference of the annular support frames, and the expansion assemblies are provided in the inner cavity of each annular support frame.

4. The natural gas hydrate branch well connection section stabilizing well wall device according to claim 3, characterized in that: The expansion assembly includes a fixed frame, a bracket, a transverse driving member and a plurality of oblique driving members. The bracket is provided on the fixed frame, the transverse driving member is provided on the bracket, and the transverse driving member is connected to the annular support frame through the oblique driving member.

5. The device for stabilizing the well wall of a natural gas hydrate branch well connection section according to claim 4, characterized in that: The transverse driving member includes a rotating shaft, a first rotating arm, a second rotating arm, a first planetary gear, a second planetary gear, an inner gear ring, a first guide rod, a second guide rod, a first slide rail, a second slide rail, a first slider, a second slider, a first worm, a second worm, a bevel gear and a trapezoidal bracket. The first planetary gear and the second planetary gear are respectively meshed with the inner gear ring. The first slider is arranged on the first slide rail and the first slider is provided with the first worm. The second slider is arranged on the second slide rail and the second slider is provided with the second worm. The two ends of the first rotating arm are respectively connected to the rotating shaft and the first planetary gear. The two ends of the second rotating arm are respectively connected to the rotating shaft and the second planetary gear. One end of the first guide rod is rotatably connected to the first planetary gear, the other end of the first guide rod is connected to the first slider, one end of the second guide rod is rotatably connected to the second planetary gear, the other end of the second guide rod is connected to the second slider, the ends of the first worm and the ends of the second worm are respectively provided with the bevel gear, and the bevel gear is connected to the oblique driving member through the trapezoidal bracket.

6. The natural gas hydrate branch well connection section stabilizing well wall device according to claim 5, characterized in that: The oblique driving member includes a connecting rod, a spring and a hinged rod, one end of the connecting rod is connected to the trapezoidal bracket, the connecting rod is a cavity structure, the spring is arranged in the cavity of the connecting rod, and one end of the spring is fixed to the inner cavity of the connecting rod, the other end of the spring is connected to the hinged rod, and the hinged rod is connected to the annular support frame.

7. The natural gas hydrate branch well connection section stabilizing well wall device according to claim 6, characterized in that: The positioning component includes a camera, a distance calibrator and an LED light strip. The camera is arranged on the outer periphery of the annular support frame, the LED light strip is arranged around the camera, and the distance calibrator is arranged on the camera.

8. The natural gas hydrate branch well connection section stabilizing well wall device according to claim 7, characterized in that: The drilling grouting assembly includes a drill rod, a drill bit, a grouting component, a slurry pipe and a slurry tank. The slurry tank is arranged on the ground. The grouting component is connected to the slurry tank through the slurry pipe, and the grouting component is connected to the main body top cover through a fixing bolt. The drill rod is arranged on the grouting component, and the drill bit is arranged on the drill rod.

9. The natural gas hydrate branch well connection section stabilizing well wall device according to claim 8, characterized in that: The rotating mechanism includes a first rotating device and a second rotating device. The lower part of the main body top cover is connected to the first rotating device. The second rotating device is provided on the main body base. The damage detection and positioning assembly is connected to the second rotating device.

10. A method for repairing damage to the well wall of a natural gas hydrate branch well connection section using the device described in any one of claims 1 to 9, characterized in that: The method comprises the following steps: Clear the site, hoist the main assembly to the support plate on the ground in advance and connect the insertion parts and drilling and grouting components, conduct inspection and test run, and ensure that the main assembly is in place stably by adjusting the main balance frame. The main assembly and the center of the wellbore should be in a straight line; Use the damage detection and positioning components to inspect and locate the wellbore wall of natural gas hydrate multi-branch wells, control the speed of the main components entering the well, and ensure that the damage detection and positioning components meet the inspection specification requirements; Use the drilling grouting assembly to drill holes at damaged parts of the wellbore wall, control the drilling speed and hole size, and simultaneously use the damage detection and positioning assembly to inspect the hole to check the depth, diameter and inclination of the hole; Use drilling grouting components to inject slurry, control the injection depth and speed of the slurry, ensure continuous injection of the slurry, and ensure the quality of the well wall repair. After the slurry injection is completed, use the damage detection and positioning components to check the well wall after repair; Lift the main components and complete the integrated process of natural gas hydrate branch well damage detection and directional grouting.

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