Cooperative treatment method for multiple disasters of top and bottom plates of coal mine

Abstract

The invention discloses a coal mine top and bottom plate multi-disaster cooperative treatment method which comprises the following steps: drilling from the ground to a coal mine top plate by using a directional drilling machine, enabling a drilling tool to enter the coal mine top plate, drilling along the coal mine top plate along a bedding layer to form a horizontal section, putting a sleeve into a drill hole, and adopting a mode of combining hydraulic sand blasting perforation and bottom seal dragging fracturing to realize multi-disaster cooperative treatment of a coal mine top plate and a coal mine bottom plate. Holes are formed in the casing pipes, high-pressure water acts on the stratum, fracturing construction is conducted on the coal mine roof, after fracturing construction is finished, the upper casing pipes are completely pulled out, secondary drilling construction is conducted through a directional drilling machine, a drilling tool penetrates through a coal seam to enter a water-bearing stratum in a coal mine bottom plate, and grouting is conducted on the water-bearing stratum. According to the method for fracturing the coal mine bottom plate and conducting advanced exploration and treatment on the coal mine bottom plate, hydraulic pressure is applied to the coal mine top plate, in the working face stoping process, high stress of the coal mine top plate is effectively released, advanced exploration and treatment are conducted on the coal mine bottom plate, and grouting transformation is conducted on a three-ash aquifer.

Description

Technical Field

[0001] The present invention relates to the technical field of mine management, and more specifically to a method for coordinated management of multiple disasters in the roof and floor of a coal mine. Background Art

[0002] Coal is an important natural resource. With the continuous exploitation of coal resources, the unmined working faces need to face increasingly complex hydrogeological conditions. For these coal mines and mining projects with complex underground hydrogeology, it is necessary to ensure that the coal mine floor aquifer is treated before mining, and to prevent the formation of a large area of ​​suspended roof structure above the goaf during mining, causing static load stress concentration of coal and rock mass, and preventing the impact of dangerous impacts on the working face.

[0003] At present, ground grouting is the most commonly used technical method to maintain the stability of coal seam aquifers. It can effectively block the water gushing channel on the bottom plate, and then combine it with hydraulic fracturing of the coal mine roof underground to reduce the static load stress concentration on the coal mine roof. However, underground fracturing and ground grouting not only take up time for underground tunnel excavation, but also need to occupy a certain amount of underground space, with high construction costs. At the same time, how to coordinate the construction process to ensure the stability of the coal mine roof is also one of the difficulties. Summary of the invention

[0004] To this end, the technical problem to be solved by the present invention is to provide a method for collaboratively managing multiple disasters in the roof and floor of a coal mine, which can reduce construction costs and improve the safety of coal mining.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions: a method for coordinated management of multiple disasters in the roof and floor of a coal mine, comprising the following steps:

[0006] Step A: Collect hydrogeological information of the coal mine roof and coal mine floor that need to be treated, and design the drilling layout location;

[0007] Step B: Use a directional drill to drill from the ground toward the roof of the coal mine. After passing through the straight hole section and the deflection section, the drill enters the roof of the coal mine and drills along the layer of the roof of the coal mine to form a horizontal section. During the drilling construction process, a casing is lowered into the borehole;

[0008] Step C: After the casing in the horizontal section is lowered, a combination of hydraulic sandblasting perforation and bottom seal drag fracturing is used to shoot holes on the casing, so that high-pressure water acts on the formation and performs fracturing construction on the coal mine roof to cut the formation and release stress. The construction is repeated in sequence to achieve staged fracturing construction of the horizontal section;

[0009] Step D: After the fracturing construction is completed, the casing is cut at a suitable position using a pipe cutter, and the upper casing is completely pulled out;

[0010] Step E: After optimizing the drilling trajectory based on the original borehole, a directional drill is used to perform secondary drilling construction, and the deflection section is reconstructed so that the drill tool passes through the coal seam and enters the aquifer in the coal mine floor, and drills along the aquifer to form a horizontal open hole section. During the drilling construction process, the casing is re-inserted into the straight hole section and the deflection section of the borehole;

[0011] Step F: Use grouting equipment to inject grout into the aquifer to fill and reinforce cracks and water channels, increase the effective thickness of the aquiclude and block the aquifer channels.

[0012] In the above-mentioned method for coordinated management of multiple disasters in the roof and floor of a coal mine, in step C, when performing segmented fracturing construction, the spacing between each segment is 50m; each segment of hydraulic sandblasting perforation includes two groups of holes, the group spacing is 20 to 27m, and each group of holes includes three holes.

[0013] In the above-mentioned method for coordinated management of multiple disasters in the roof and floor of a coal mine, in step B, the drill tool drills along the center of the coal mine roof after passing through the inclined section. The closer the suspended surface above the goaf is to the middle position, the greater the suspended distance is, and the more concentrated the stress is. Drilling along the direction of the coal mine at the center of the coal mine roof can quickly and effectively release stress and reduce the construction workload. In step E, the drill tool drills along one side of the coal mine floor after passing through the inclined section to form a first borehole, and then drills the nth borehole parallel to the direction of the first borehole in the direction of the other side of the coal mine floor in sequence, and in each borehole After the construction is completed, grouting construction is carried out to release the stress of the coal mine roof first. The impact of grouting on the stratum will not affect the coal mine roof, thus ensuring the safety of the entire construction process; first, grouting is carried out on one side of the coal mine floor. Since the edge of the coal mine floor bears the pressure of the stratum and has a higher stability, the grouting has little impact on the mining surface, and grouting construction with higher pressure and flow can be carried out. Subsequently, when grouting is carried out in sequence, due to the reinforcement layer formed by the previous grouting, the strength of the bottom layer gradually increases, and the subsequent impact on the stratum becomes smaller and smaller, thus ensuring the safety of the construction.

[0014] In the above-mentioned method for coordinated management of multiple disasters in the roof and floor of a coal mine, in step B, during the drilling process toward the roof of the coal mine, three levels of apertures are used for drilling holes, each of which is matched with three levels of casing.

[0015] The above-mentioned method for coordinated multi-hazard management of coal mine roof and floor plates has a first-level hole diameter of 444.5mm, and a 339.7mm diameter casing is lowered to a depth of 5 to 10m in the bedrock; the second-level hole diameter is 311.1mm, and a 244.5mm diameter casing is lowered to the stable sandstone layer above the coal seam; the tertiary hole diameter is 215.9mm, and after drilling to the final hole depth, a 139.7mm diameter casing is lowered.

[0016] In the above-mentioned method for coordinated multi-hazard management of coal mine roof and floor, in step E, when drilling into the aquifer in the coal mine floor, the first-level opening shares a straight hole section with step B; the second-level opening has an aperture of 215.9 mm, and a casing with a diameter of 177.8×8.05 mm is inserted down to the mudstone above the aquifer; the tertiary opening is a bare hole drilled in the aquifer, with a diameter of 152.4 mm.

[0017] In the above-mentioned method for coordinated management of multiple disasters in the roof and floor of a coal mine, in step B, the drill tool drills into the inner layer of the stable sandstone of the coal mine roof; in step E, the drill tool drills into the inner layer of the three-ash aquifer.

[0018] In the above-mentioned method for coordinated management of multiple disasters in the roof and floor of a coal mine, when drilling is carried out in the roof and floor of the coal mine, the horizontal drilling direction is parallel to the inclination of the stratum.

[0019] The technical solution of the present invention achieves the following beneficial technical effects:

[0020] The present invention provides a method for simultaneously implementing fracturing and advanced exploration and treatment of a coal mine floor with a single hole. By applying hydraulic pressure to the coal mine roof, the high stress of the coal mine roof can be effectively released during the mining process of the working face. In addition, by conducting advanced exploration and treatment of the coal mine floor, the three-ash aquifer is grouting-transformed to make the slurry diffuse evenly to form an effective barrier and seal the cracks, fill and reinforce the cracks and water-conducting channels, transform the three-ash aquifer of the 6 coal floor, increase the effective thickness of the water-blocking layer and block the aquifer channel.

[0021] Compared with the traditional underground fracturing and ground grouting treatment, the present invention greatly improves the construction efficiency and reduces the risk of underground construction. Its technical application range is wide, and it is suitable for coal seam treatment and treatment scenarios in mines, and has high application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A schematic plan view of the roof and floor treatment of a coal mine according to the present invention;

[0023] Figure 2 A schematic cross-sectional view of the coal mine roof and floor treatment according to the present invention. DETAILED DESCRIPTION

[0024] A method for coordinated management of multiple disasters in the roof and floor of a coal mine in this embodiment includes the following steps:

[0025] 1. Geological parameter investigation and analysis

[0026] 1.1. Collect hydrogeological information of the coal mine roof and coal mine floor that need to be treated, including the structural development of the proposed treatment area, the bedding structure of the coal seam roof and floor, and the thickness of the limestone aquifer.

[0027] 1.2. Analyze the hydrogeological characteristics of the coal mine roof and floor, determine the fracturing layer in the coal mine roof, select stable sandstone to drill along the layer, and carry out hydraulic fracturing construction; in the coal mine floor, select the three-ash aquifer as the target layer for grouting treatment, and carry out grouting treatment on the coal mine floor along the three-ash target layer.

[0028] 2. Drilling arrangement and positioning

[0029] 2.1. Considering the inclination and dip of the underground coal seam, the directions of the horizontal holes in the roof and floor of the coal mine should be kept parallel to the inclination of the strata as much as possible to reduce the difficulty of drilling construction. The diffusion law of the grouting slurry should be followed and the appropriate hole mouth position should be selected to arrange the drilling.

[0030] 3. Coal mine roof fracturing construction

[0031] 3.1 Use a directional drill to drill from the ground toward the roof of the coal mine. After passing through the straight hole section and the inclined section, the drill tool enters the roof of the coal mine. After passing through the inclined section, the drill tool drills along the center of the roof of the coal mine and drills along the layer of the roof of the coal mine to form a horizontal section. During the drilling construction process, the casing is lowered into the borehole.

[0032] The drilling adopts three-level aperture, which is matched with three-level casing. The first-level aperture is 444.5mm, and the casing with a diameter of 339.7mm is lowered to a depth of 5 to 10m in the bedrock; the second-level aperture is 311.1mm, and the casing with a diameter of 244.5mm is lowered to the stable sandstone layer above the coal seam; the third-level aperture is 215.9mm, and after drilling to the final hole depth, the casing with a diameter of 139.7mm is lowered.

[0033] 3.2. After the casing in the horizontal section is lowered, a combination of hydraulic sandblasting perforation and bottom seal dragging fracturing is used. Hydraulic sandblasting perforation is to use continuous oil pipes to supply high-pressure water into the sandblasting perforation device to achieve high-speed jet cutting, shoot holes on the casing, and make the high-pressure water act on the formation to perform fracturing construction on the coal mine roof, so as to release the stress of the cutting formation, and repeat the construction in sequence to achieve staged fracturing construction of the horizontal section. Both hydraulic sandblasting perforation equipment and bottom seal dragging fracturing equipment are existing technologies.

[0034] When performing staged fracturing construction, the spacing between each section is 50m. Each section of hydraulic sandblasting perforation includes two groups of holes with a group spacing of 20 to 27m. It is necessary to avoid the casing coupling. Each group of holes includes three holes, and 40 groups of cracks are initially formed in the horizontal section to cut the formation to the maximum extent and effectively release the high stress.

[0035] 4. Cutting and pulling casing construction

[0036] 4.1. After the fracturing construction of the coal mine roof is completed, before the construction of the coal mine floor grouting treatment hole, the same straight hole section needs to be used to re-optimize the trajectory for the second opening. Therefore, two inclined sections need to be constructed, and pipe cutting and pulling construction is required. The successful implementation of pipe cutting and pulling construction is the basis for the next step of the coal mine floor horizontal branch hole construction process.

[0037] 4.2. Use a mechanical internal cutter to cut the pipe. The mechanical internal cutter is a special tool for cutting pipes from the inside of the downhole pipe string. It can cut at any position except the coupling. During the cutting operation, a retractable salvage spear can be connected to the upper part of the internal cutter. After the cutting is completed, the upper pipe string can be pulled out at once.

[0038] 5. Coal mine floor grouting treatment construction

[0039] 5.1 After the casing is cut and pulled out, the trajectory is re-optimized to carry out the construction of the deflection section, so that the borehole passes through the main mining seam of the 6 coal, enters the three-ash aquifer, and is drilled along the three-ash aquifer to form a horizontal bare hole section. After the main hole construction is completed, the construction of the horizontal branch hole is entered. During the drilling construction process, the casing is re-inserted into the straight hole section and the deflection section of the borehole. When drilling into the aquifer in the coal mine floor, the first-level opening shares a straight hole section with step B; the second-level opening has an aperture of 215.9 mm, and a casing with a diameter of 177.8×8.05 mm is inserted to the upper mudstone of the aquifer; the third-level opening is a bare hole drilled in the aquifer with an aperture of 152.4 mm.

[0040] 5.2. After passing through the inclination section, the drill tool drills along one side of the coal mine floor to form the first borehole, and then drills the nth borehole in parallel with the first borehole in the direction of the other side of the coal mine floor; after each borehole is completed, grouting equipment is used to inject grout into the aquifer to fill and reinforce the cracks and water channels, increase the effective thickness of the aquiclude and block the aquifer channels.

[0041] The present invention aims at isolated working faces or working faces with concentrated stress. By respectively applying hydraulic pressure to the coal mine roof and conducting advance exploration and treatment on the coal mine bottom plate, a one-hole-multiple-purpose process is adopted to achieve effective treatment of the isolated working face. Moreover, by optimizing the construction sequence and process and releasing the stress of the coal mine roof first, the stress of the coal mine roof has been released during grouting and will not be affected by grouting, so that stress concentration or uneven force will not occur, thereby ensuring the safety of the coal mine and the safety of the entire construction, greatly improving the safety of the construction. The method is simple, effective, highly operable, and can effectively improve the water hazard prevention and control capabilities of mine engineering.

[0042] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the claims of this patent application.

Claims

1. A method for coordinated management of multiple disasters in coal mine roof and floor, characterized in that: The following steps are involved: Step A: Collect hydrogeological information of the coal mine roof and coal mine floor that need to be treated, and design the drilling layout location; Step B: Use a directional drill to drill from the ground toward the roof of the coal mine. After passing through the straight hole section and the deflection section, the drill enters the roof of the coal mine and drills along the layer of the roof of the coal mine to form a horizontal section. During the drilling construction process, a casing is lowered into the borehole; Step C: After the casing in the horizontal section is lowered, a combination of hydraulic sandblasting perforation and bottom seal drag fracturing is used to shoot holes on the casing, so that high-pressure water acts on the formation and performs fracturing construction on the coal mine roof to cut the formation and release stress. The construction is repeated in sequence to achieve staged fracturing construction of the horizontal section; Step D: After the fracturing construction is completed, the casing is cut at a suitable position using a pipe cutter, and the upper casing is completely pulled out; Step E: After optimizing the drilling trajectory based on the original borehole, a directional drill is used to perform secondary drilling construction, and the deflection section is reconstructed so that the drill tool passes through the coal seam and enters the aquifer in the coal mine floor, and drills along the aquifer to form a horizontal open hole section. During the drilling construction process, the casing is re-inserted into the straight hole section and the deflection section of the borehole; Step F: Use grouting equipment to inject grout into the aquifer to fill and reinforce cracks and water channels, increase the effective thickness of the aquiclude and block the aquifer channels.

2. A method for coordinated management of multiple disasters in coal mine roof and floor according to claim 1, characterized in that: In step C, when performing staged fracturing construction, the spacing between each stage is 50m; each stage of hydraulic sandblasting perforation includes two groups of holes, the group spacing is 20-27m, and each group of holes includes three holes.

3. A method for coordinated management of multiple disasters in coal mine roof and floor according to claim 1, characterized in that: In step B, the drill tool drills along the center of the coal mine roof after passing through the inclined section; in step E, the drill tool drills along one side of the coal mine floor after passing through the inclined section to form a first borehole, and then drills the nth borehole parallel to the first borehole in the direction of the other side of the coal mine floor, and performs grouting after each borehole is completed.

4. A method for coordinated management of multiple disasters in coal mine roof and floor according to claim 1, characterized in that: In step B, during the drilling process toward the roof of the coal mine, the borehole adopts three-level apertures, each matched with three-level casings.

5. A method for coordinated management of multiple disasters in coal mine roof and floor according to claim 4, characterized in that: The first-level hole has a diameter of 444.5mm, and a 339.7mm diameter casing is lowered to a depth of 5 to 10m in the bedrock; the second-level hole has a diameter of 311.1mm, and a 244.5mm diameter casing is lowered to the stable sandstone layer above the coal seam; the third-level hole has a diameter of 215.9mm, and after drilling to the final hole depth, a 139.7mm diameter casing is lowered.

6. A method for coordinated management of multiple disasters in coal mine roof and floor according to claim 4, characterized in that: In step E, when drilling into the aquifer in the coal mine floor, the first-level opening shares a straight hole section with step B; the second-level opening has a diameter of 215.9 mm, and a casing with a diameter of 177.8×8.05 mm is inserted down to the mudstone above the aquifer; the third-level opening is a bare hole drilled in the aquifer, with a diameter of 152.4 mm.

7. A method for coordinated management of multiple disasters in coal mine roof and floor according to claim 1, characterized in that: In step B, the drilling tool drills into the stable sandstone layer of the coal mine roof and drills along the layer; in step E, the drilling tool drills into the three-ash aquifer and drills along the layer.

8. The method for coordinated management of multiple disasters in coal mine roof and floor according to claim 1, characterized in that: When drilling in the coal mine roof and coal mine floor, the horizontal drilling direction is parallel to the inclination of the stratum.

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