A method of repairing a small range damaged wellbore

Abstract

The application discloses a kind of small range broken wellbore repair method, and operation personnel is realized in broken area by the working platform that can be lifted in wellbore after setting steel framework grouting, steel framework includes the anchor rod of horizontal setting and the vertical fixed sealing plate component of outer end thereof, after grouting is completed, steel framework is repaired while with original rock formation firm whole wellbore shape, to ensure that wellbore is safely operated for a long time after repair.It is specifically described that, through the working platform that can be lifted in wellbore, repair operation is realized, operation personnel can go back and forth to broken area many times, first, accurate measurement is carried out to broken area, then, accurate production of steel framework is carried out according to measurement result, to ensure that accurate, stable repair of wellbore is carried out after steel framework installation and grouting.

Description

Technical Field

[0001] This invention belongs to the field of mine safety and relates to a method for repairing a small-scale damaged shaft. Background Technology

[0002] In mining engineering, shafts with different functions are arranged as longitudinal passages connecting the surface and underground spaces, serving as vital engineering projects throughout the entire life cycle of the mine. To ensure the long-term operation of the shafts, a high-strength concrete structure is usually laid around the perimeter of the shaft as the shaft wall during the excavation process.

[0003] Well shafts typically have the following three functions:

[0004] (1) To facilitate the movement of personnel, equipment, and materials up and down;

[0005] (2) To undertake the functions of mine ventilation, drainage, and communication;

[0006] (3) To undertake the functions of hoisting and chute of ore / waste rock.

[0007] In engineering practice, well wall damage is a common occurrence due to various factors such as fractured rock mass, groundwater, pipeline load, and engineering disturbance.

[0008] Relatively speaking, shafts that perform the first (1) and second (2) functions are more likely to suffer minor damage due to the aforementioned factors, while shafts that perform the third (3) function are also subject to the impact of ore, so they are more likely to suffer major damage.

[0009] Due to the limited concrete wall structure and confined working space of the well shaft, secondary repairs are difficult once the well wall is damaged. In most cases, the damaged area is simply treated with shotcrete. After a period of operation, this simple treatment method often results in peeling and loosening of the repaired area, and the damaged area gradually expands, greatly threatening the safe operation of the well shaft. Summary of the Invention

[0010] The purpose of this invention is to provide a method for accurately and stably repairing wellbore wall damage that performs the functions of (1) and (2) mentioned above.

[0011] The present invention provides a method for repairing small-area damaged well casings. Workers use a work platform that can be raised and lowered within the well casing to install a steel frame in the damaged area before grouting. The steel frame includes horizontally positioned anchor rods and sealing plates with vertically fixed outer ends. After grouting, the steel frame repairs the shape of the well wall while forming a solid integral structure with the original rock. The method specifically includes the following steps:

[0012] (1) Production of work platform and card components;

[0013] (2) The work platform carries the workers down into the well to measure the volume of the damaged area and the area of ​​the corresponding well wall;

[0014] (3) The work platform carries the workers to the well, and after determining the arrangement and quantity of anchor bolts in the damaged area, the sealing plate components are made;

[0015] (4) The working platform carries the workers, anchor bolts and drilling equipment down the well;

[0016] (5) Install a clamp between the working platform and the well wall to position the working platform;

[0017] (6) Install anchor bolts after drilling horizontally in the damaged area of ​​the well wall;

[0018] (7) The working platform is raised to the surface and the sealing plate components are transported down into the well;

[0019] (8) Install sealing plate components at the outer end of the anchor bolt;

[0020] (9) Lower the main grouting pipe, and the workers inject grout into the damaged area through the hollow rod;

[0021] (10) After the grouting is completed, the working platform carries the workers and equipment to the well.

[0022] When the above method is implemented, the anchor rod includes a solid rod and a hollow rod. The hollow rod is provided with a discharge hole and a plug at its outer end. The outer ends of the solid rod and the hollow rod are respectively connected to nuts for locking the sealing plate component.

[0023] When the above method is implemented, the anchor rods are arranged in horizontal rows and vertical columns, with the hollow rod in the middle of each row serving as a grouting pipe.

[0024] When the above method is implemented, the sealing plate component includes a steel mesh frame and a sealing plate fixed at its outer end, and the sealing plate is provided with anchor bolt mounting holes.

[0025] When the above method is implemented, the anchor bolt mounting hole is an oblong hole.

[0026] In the above method, the working platform is a steel structure with a diameter smaller than that of the well shaft, and lifting is achieved by setting a winch at the wellhead.

[0027] In the above method, the clamp is a Z-shaped structure, with its bottom folded edge fastening to the bottom surface of the working platform and its top folded edge inserted into the well wall.

[0028] In the above method, grouting is performed sequentially from bottom to top.

[0029] This invention involves installing a steel frame in the damaged area of ​​the well wall before grouting. This allows the steel frame to repair the well wall while simultaneously forming a stable whole with the surrounding original rock, thus ensuring the long-term safe operation of the wellbore after repair. Specifically, the repair work is carried out using a work platform that can be raised and lowered within the wellbore. Workers can repeatedly travel to and from the damaged area to accurately measure it, and then accurately fabricate the steel frame based on the measurement results. This ensures accurate and stable repair of the well wall after the steel frame is installed and grouted. Attached Figure Description

[0030] Figure 1 This is a schematic diagram showing the state of the anchor bolt after its installation in one embodiment of the present invention.

[0031] Figure 2 This is a schematic diagram showing the state of the sealing plate component being lowered into the well.

[0032] Figure 3 This is a schematic diagram showing the state of the sealing plate component and anchor bolt after installation and fixation.

[0033] Figure 4 A schematic diagram showing the completed grouting process for the damaged area.

[0034] Figure 5 This is a schematic diagram of the final state after repair.

[0035] Number in the diagram:

[0036] 1-Work platform;

[0037] 2-Anchor bolt;

[0038] 3-Sealing plate components;

[0039] 31-Reinforcing steel mesh;

[0040] 32-Sealing plate; Detailed Implementation

[0041] The present invention discloses a method for repairing a small-scale damaged wellbore. The general scheme is as follows: the operator sets up a steel frame in the damaged area using a working platform that can be raised and lowered in the wellbore, and then injects grout. The steel frame includes horizontally set anchor rods and sealing plate components with their outer ends fixed vertically. After the grouting is completed, the steel frame repairs the shape of the well wall and forms a solid whole with the original rock.

[0042] The lifting and lowering of the working platform 1 is achieved by a winch installed at the wellhead (only the wire rope of the winch is shown in the figure).

[0043] The working platform 1 uses a steel structure with a diameter smaller than that of the well shaft. This can be achieved by using a steel frame with steel plates laid on it, or by using thicker steel plates directly. In both structures, lifting rings are installed at the center and perimeter of the steel plates, connecting steel wire ropes (central suspension plus a perimeter suspension) to ensure stable lifting and lowering of the working platform. Only the steel wire rope connected at the center is shown in the diagram.

[0044] Since the installation of the steel frame involves drilling holes and installing anchor bolts, in order to ensure the stability of the workers standing on the work platform, after the work platform is lowered into place, a clamp (not shown in the figure) is installed between its perimeter and the well wall. The clamp adopts a Z-shaped structure, with its bottom folded edge fastening to the bottom surface of the work platform and its top folded edge inserting into the well wall.

[0045] The specific structure of the steel frame is as follows:

[0046] like Figures 1 to 5 As shown, anchor rod 2 consists of a solid rod and a hollow rod. The hollow rod serves as a grouting pipe, with a discharge hole and a plug at its outer end. Nuts are connected to the outer ends of both the solid and hollow rods.

[0047] The length of the anchor bolt is determined by the outer end extending approximately one nut thickness beyond the well wall.

[0048] The anchor bolts are arranged in horizontal and vertical rows according to the specific data of the damaged area, with a hollow rod placed in the middle of each row.

[0049] The sealing plate component 3 includes a steel mesh frame 31 and a sealing plate 32 welded and fixed to its outer end. The sealing plate is provided with mounting holes corresponding to the total number of anchor rods.

[0050] Since the anchor rods are installed after drilling holes with a drilling machine, it may not be possible to guarantee the precise position of each anchor rod. Therefore, the installation holes are set as elongated holes to facilitate the assembly of the sealing plate and the anchor rods.

[0051] The specific construction steps are as follows:

[0052] (1) Install a winch at the wellhead;

[0053] (2) Fabricate the working platform and fixtures outside the well;

[0054] (3) Suspend the working platform with the wire rope of the winch;

[0055] (4) The work platform carries the workers down into the well to measure the volume of the damaged area and the area of ​​the corresponding well wall;

[0056] (5) The work platform carries the workers to the well, and after determining the arrangement and quantity of anchor bolts in the damaged area, the sealing plate components are made;

[0057] (6) The working platform carries the workers, anchor bolts and drilling equipment down the well;

[0058] (7) Install a clamp between the working platform and the well wall to position the working platform;

[0059] (8) Install anchor bolts after drilling horizontally in the damaged area of ​​the well wall;

[0060] (9) The working platform is raised to the surface and the sealing plate components are transported down into the well;

[0061] (10) Install the sealing plate components.

[0062] Remove the nuts from all the anchor bolts, pass the mounting holes on the sealing plate through the anchor bolts, and then tighten the nuts so that the sealing plate is aligned with the position of the well wall.

[0063] (11) Lower the main grouting pipe and the workers inject grout into the damaged area through the hollow rod.

[0064] Grouting proceeds sequentially from bottom to top. First, the plug at the end of the lowest hollow rod is opened, and then grouting is performed after the main grouting pipe is connected to the hollow rod.

[0065] The grouting volume for each hollow rod is calculated based on the measured volume of the damaged area and the corresponding height of the hollow rod. Therefore, grouting requires coordination between the upper and lower sections, strict control of the grouting time, and ensuring sufficient grout volume.

[0066] In addition, since the grouting material is a high-concentration paste containing a large amount of aggregate, it can hardly seep out through narrow gaps, so there is no need to seal the gaps between the sealing plate and the surrounding original rock.

[0067] (12) After the grouting is completed, the working platform carries the workers and equipment to the well.

[0068] This invention utilizes a working platform that can be raised and lowered within the wellbore to perform repair work. Workers can repeatedly travel to and from the damaged area to accurately measure it, and then precisely fabricate the steel frame based on the measurement results. This ensures accurate and stable repair of the well wall after the steel frame is installed and grouted. After repair, the steel frame forms a stable whole with the surrounding original rock, thus guaranteeing the long-term safe operation of the wellbore.

Claims

1. A method for repairing a well casing with small-scale damage, characterized in that: In this method, workers use a work platform that can be raised and lowered within the wellbore to install a steel frame in the damaged area before grouting. The steel frame includes horizontally installed anchor bolts and sealing plates with their outer ends vertically fixed. After grouting is completed, the steel frame repairs the shape of the well wall while forming a solid integral structure with the original rock. The specific steps include: (1) Production of work platform and card components; (2) The work platform carries the workers down into the well to measure the volume of the damaged area and the area of ​​the corresponding well wall; (3) The work platform carries the workers to the well, and after determining the arrangement and quantity of anchor bolts in the damaged area, the sealing plate components are made; (4) The working platform carries the workers, anchor bolts and drilling equipment down the well; (5) Install a clamp between the working platform and the well wall to position the working platform; (6) Install anchor bolts after drilling horizontally in the damaged area of ​​the well wall; (7) The working platform is raised to the surface and the sealing plate components are transported down into the well; (8) Install sealing plate components at the outer end of the anchor bolt; (9) Lower the main grouting pipe, and the workers inject grout into the damaged area through the hollow rod; (10) After the grouting is completed, the working platform carries the workers and equipment to the well.

2. The method as described in claim 1, characterized in that: The anchor rod includes a solid rod and a hollow rod. The hollow rod has a discharge hole and a plug at its outer end. The outer ends of the solid rod and the hollow rod are respectively connected to nuts for locking the sealing plate component.

3. The method as described in claim 2, characterized in that: The anchor bolts are arranged in horizontal rows and vertical columns, with the hollow rod in the middle of each row serving as a grouting pipe.

4. The method as described in claim 1, characterized in that: The sealing plate component includes a steel mesh frame and a sealing plate fixed at its outer end, and the sealing plate is provided with anchor bolt mounting holes.

5. The method as described in claim 4, characterized in that: The anchor bolt mounting hole is an oblong hole.

6. The method as described in claim 1, characterized in that: The working platform is a steel structure with a diameter smaller than that of the well shaft, and lifting is achieved by installing a winch at the wellhead.

7. The method as described in claim 1, characterized in that: The clamp has a Z-shaped structure, with its bottom folded edge fastening to the bottom surface of the working platform and its top folded edge inserting into the well wall.

8. The method as described in claim 1, characterized in that: During grouting, grout is injected sequentially from bottom to top.

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