A method for large-area gas control

Abstract

This invention relates to the field of coal mining technology, specifically to a method for large-area gas control. The method comprises the following steps: delineating the boundary of the large-area gas control zone; using a TBM (Tube Milling Machine) to excavate a boundary roadway starting from the center of the boundary of the large-area gas control zone; excavating a connecting roadway within the area enclosed by the boundary roadway; drilling a through borehole within the coal seam area enclosed by the connecting roadway and the boundary roadway; and using fracturing and extraction technology to extract gas within the through borehole. Utilizing the rapid roadway construction advantage of the TBM, long-distance, high-efficiency rock breaking operations can be achieved, improving the mechanization and intelligence level of the working face. Following drilling and gas extraction, compared to traditional mechanized mining and blasting, this method significantly reduces disturbance to the surrounding rock, lowers the probability of coal and gas outbursts, effectively improves gas control efficiency, and enables safe and efficient mining of deep coal resources, effectively solving the corresponding technical problems existing in the prior art.

Description

Technical Field

[0001] This invention relates to the field of coal mining technology, and specifically to a method for large-area gas control. Background Technology

[0002] As shallow resources are depleted, coal mining continues to extend to deeper areas. Mineral resources with better conditions are gradually being exhausted, and the number of gas-bearing mines is increasing. After entering deeper areas, the possibility of coal and gas outbursts, gas explosions, and other disasters caused by gas is higher and more serious, which urgently needs to be addressed.

[0003] In existing technologies, traditional mechanical excavation methods are mainly employed, which involve using the milling head at the front of the cantilever tunneling machine to strip the coal and rock mass. The stripped coal and rock are then scraped onto the onboard conveyor system via a star disk on the front shovel plate of the cantilever tunneling machine. The slag is then removed via a belt conveyor system attached to the rear of the cantilever tunneling machine, a rail-mounted mine car, or a trackless rubber-tired car. Corresponding tunnel maintenance is also carried out.

[0004] Alternatively, blasting methods can be used, such as the method for rapid tunneling and continuous support of coal mine roadways in application number 201310469323.0. This method mainly involves drilling holes manually or mechanically, loading explosives and blasting, and removing slag through belt conveyor systems, scraper conveyors, rail mine cars, or trackless rubber-tired vehicles, while also carrying out corresponding roadway maintenance.

[0005] Both of the above methods suffer from significant disturbance to the surrounding rock, poor rock-breaking efficiency, low tunneling efficiency, and a poor working environment. Furthermore, they are mostly applicable to localized outburst prevention and have considerable limitations in actual engineering projects, greatly increasing mining costs. Summary of the Invention

[0006] In view of this, the purpose of the present invention is to provide a method for large-area gas control to solve the above-mentioned technical problems existing in the prior art.

[0007] To achieve the above objectives, the large-area gas control method provided by this invention adopts the following technical solution:

[0008] A method for controlling gas pollution in large areas, comprising the following steps:

[0009] Delineate the boundaries of large-scale gas control areas;

[0010] The TBM starts from the center of the boundary of the large-area gas control area and excavates the boundary tunnel along the boundary of the large-area gas control area;

[0011] TBMs excavate connecting tunnels within the area enclosed by the boundary tunnels;

[0012] Within the coal seam area enclosed by the connecting passageway and the boundary passageway, two directional drilling rigs are used to drill through boreholes in both directions.

[0013] Gas extraction was carried out using fracturing extraction technology within the through borehole.

[0014] The beneficial effects of the large-area gas control method provided by this invention are as follows: Utilizing the advantages of TBM rapid roadway formation, it enables long-distance, high-efficiency rock breaking operations, greatly improving rock breaking efficiency, significantly reducing construction workload, enhancing the mechanization and intelligence level of the working face, and exhibiting strong applicability. It allows for less-manned operation, which is conducive to improving construction efficiency and safety. Subsequently, drilling and gas extraction are carried out. Compared with traditional mechanized mining and blasting, it significantly reduces disturbance to the surrounding rock, lowers the probability of coal and gas outbursts, effectively improves gas control efficiency, and enables safe and efficient mining of deep coal resources, effectively solving the corresponding technical problems existing in the prior art.

[0015] Furthermore, two TBMs are used to excavate the boundary passage. Starting from the center of the large-area gas control area, one TBM excavates clockwise and the other counterclockwise to form the boundary roadway. The two TBMs excavate simultaneously from the center without interfering with each other, which further improves the efficiency of roadway formation, shortens the construction period, and allows the equipment to be disassembled and used for other projects after construction, saving costs.

[0016] Furthermore, before excavating the connecting tunnel, a launching shaft is set on the boundary of the area surrounded by the boundary tunnel, and a receiving shaft is set on the opposite side of the launching shaft and on the boundary of the area surrounded by the boundary tunnel; the TBM starts from the launching shaft and ends at the receiving shaft to excavate the connecting tunnel.

[0017] Furthermore, the launching well is used for the assembly of the TBM, and the receiving well is used for the disassembly of the TBM.

[0018] Furthermore, there is one or more connecting passageways. When there is one or more connecting passageways, each connecting passageway is evenly distributed within the area enclosed by the boundary passageway.

[0019] Furthermore, the directional drilling rig is a kilometer-deep drilling rig.

[0020] Furthermore, the width or length of the coal seam area surrounded by the connecting passageway and the boundary passageway meets the requirements for two kilometer-long drilling rigs to drill through holes in both directions.

[0021] Furthermore, the width or length of the coal seam area surrounded by the connecting passageway and the boundary passageway is 600m.

[0022] Furthermore, the fracturing extraction process is segmented fracturing extraction.

[0023] Furthermore, the segmented fracturing extraction utilizes packers or bridge plugs to separate the segments. Attached Figure Description

[0024] Figure 1 This is a flowchart of the large-area gas control method provided by the present invention;

[0025] Figure 2 This is a schematic diagram of TBM tunneling in the large-area gas control method provided by the present invention. Figure 1 (The connecting passageway has not yet been formed);

[0026] Figure 3 This is a schematic diagram of TBM tunneling in the large-area gas control method provided by the present invention. Figure 2 (The connecting passageway was formed);

[0027] Figure 4 This is a schematic diagram showing the location of the extraction roadway and the coal seam in this invention.

[0028] The map is labeled as follows: 1. "U" shaped tunnel; 2. Starting shaft; 3. Receiving shaft; 4. Connecting passageway; 5. Center. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention are within the scope of protection of the present invention.

[0030] To enable those skilled in the art to better understand and implement the technical solutions of the present invention, the present invention will be further described below in conjunction with specific embodiments and accompanying drawings.

[0031] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0032] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature; in the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0033] In the description of this invention, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0034] In the description of this invention, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature and the second feature are in direct contact, or that the first feature and the second feature are in indirect contact through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0035] Coal mines are prone to various accidents during the mining process, such as gas explosions, coal dust explosions, coal and gas outbursts, poisoning, asphyxiation, fires, water inrushes, and roof collapses. Among these accidents, gas explosions are undoubtedly the most serious, causing the greatest losses and occurring most frequently. According to annual accident statistics from the National Coal Mine Safety Administration, the vast majority of major coal mine accidents resulting in 10 or more deaths are caused by gas explosions, accounting for approximately 70% of all major accidents. Therefore, gas can be considered the greatest threat to coal mine safety. Thus, gas extraction in coal mines to reduce gas levels is of paramount importance.

[0036] To alleviate this problem, the inventors considered the advantage of full-face tunnel boring machines (TBMs) in rapidly constructing tunnels. Applying TBMs to large-area gas control can effectively reduce disturbance to the surrounding rock, thereby lowering the probability of coal and gas outbursts. Therefore, the technical solution of this invention is designed as follows:

[0037] like Figure 1As shown, a method for controlling gas in a large area includes the following steps:

[0038] S101. Delineate the boundaries of large-area gas control zones based on actual engineering conditions;

[0039] Based on the mining area scope of gas extraction and the existing roadway layout, the boundary of the large-area gas control zone is determined by comprehensively comparing extraction effectiveness, construction period, and cost.

[0040] S102 and TBM start from the center of the boundary of the large-area gas control area and excavate the boundary tunnel along the boundary of the large-area gas control area;

[0041] Utilizing the advantages of TBM for rapid tunneling, long-distance, high-efficiency rock breaking operations can be achieved, greatly improving rock breaking efficiency, realizing integrated tunneling and anchoring, significantly reducing construction work, improving the mechanization and intelligence level of the working face, having strong applicability, enabling less-manned operations, and helping to improve construction efficiency and safety, followed by drilling and gas extraction.

[0042] The number of TBMs to be used is selected based on the size of the gas zone division; it can be one, two, or three units, and this invention does not impose any restrictions on this.

[0043] In this embodiment of the invention, two TBMs are used. The two TBMs start from the center position 5 of the large-area gas control area, one tunneling clockwise and the other counterclockwise, forming a "U"-shaped tunnel 1. The "U"-shaped tunnel 1 is the boundary tunnel, as shown below. Figure 2 and Figure 3 As shown, two TBMs simultaneously excavate from point 5 at the boundary of the large-area gas control zone without interfering with each other, which can further improve tunneling efficiency, shorten the construction period, and the equipment can be disassembled and used for other projects after construction is completed, saving costs.

[0044] S103 and TBM excavate connecting tunnels within the area enclosed by the boundary tunnels;

[0045] like Figure 3 As shown, a launching shaft 2 is set on the boundary of the area surrounded by the "U"-shaped tunnel 1, and a receiving shaft 3 is set on the opposite side of the launching shaft 2, on the boundary of the area surrounded by the "U"-shaped tunnel. The TBM is assembled at the launching shaft 2, excavates and enters the connecting tunnel 4, and ends its excavation at the receiving shaft 3, where it is disassembled. In this embodiment of the invention, the TBM is assembled at the launching shaft 2 of one connecting tunnel 4, disassembled at the receiving shaft 3, and then moves to the launching shaft 2 of another connecting tunnel 4 for reassembly, thus completing the excavation of each connecting tunnel 4 in sequence.

[0046] Depending on the size of the area enclosed by the boundary roadway, one or more connecting roadways 4 can be set up, evenly distributed within the area enclosed by the boundary roadway, thus dividing the coal seam enclosed by the boundary roadway into two or more regions. As in this invention... Figure 3 As shown, a total of 8 connecting tunnels were excavated, dividing the large area of ​​gas control into 8 smaller areas to facilitate gas extraction.

[0047] S104. In the coal seam area surrounded by connecting passageways and boundary passageways, two directional drilling rigs are used to drill through holes in both directions.

[0048] The width or length of the coal seam area enclosed by the connecting passageway and the boundary passageway is sufficient to allow two directional drilling rigs to drill a through borehole in both directions; the shape of the coal seam area enclosed by the connecting passageway and the boundary passageway is not limited; the approximate shape may be elliptical or square.

[0049] In this embodiment of the invention, the directional drilling rig is a kilometer-long drilling rig, and the width or length of the coal seam area surrounded by the connecting tunnel and boundary tunnel is 600m. It should be noted that 600m is only a reference value and does not mean that it must be 600m. In actual construction, it can also be greater than 600m. Figure 4 During operation, the boreholes are formed by drilling from the two connecting passageways 4 upwards to the coal seams that need to be extracted.

[0050] S105. Gas extraction is carried out using fracturing extraction technology in a through borehole.

[0051] This invention utilizes a staged fracturing method for gas extraction. Staged fracturing involves separating the coal seam into sections using packers or bridge plugs, then fracturing each section sequentially to create multiple fractures within each wellbore. It typically involves three stages: first, pre-fracturing fluid (without proppant) is pumped into the coal seam borehole; then, fracturing fluid containing a certain concentration of proppant (usually sand) is pumped into the coal seam; and finally, fracturing fluid with an even higher concentration of proppant is used for further fracturing. Staged fracturing allows for large-scale fracturing of the coal seam in a short time, minimizing damage to the coal seam. The borehole remains unaffected by goaf damage, and gas extraction is unaffected, achieving rapid extraction.

[0052] Compared to traditional mechanized mining and blasting, this invention leverages the advantages of TBM tunneling, significantly reducing disturbance to the surrounding rock, lowering the probability of coal and gas outbursts, effectively improving tunneling efficiency, and enabling safe and efficient mining of deep coal resources. It effectively solves the corresponding technical problems existing in the prior art.

[0053] During the implementation of the invention, the directional drilling rigs used were kilometer-scale directional drilling rigs, specifically the ZYWC-6500 / 55 type directional drilling rig produced by Jiangsu Zhongmei Mining Equipment Co., Ltd., and the ZDY6000LD(B) type directional drilling rig produced by Xi'an Research Institute of China Coal Technology & Engineering Group Co., Ltd.

[0054] The drilling process of a kilometer-long directional drilling rig is as follows:

[0055] a) Investigation and analysis of directional drilling conditions in gas drainage roadways: Analyze geological conditions, coal seam occurrence, coal and rock mass distribution and related properties to determine the drilling strata;

[0056] b) Determine the location: Determine the drilling location based on the mining layout plan;

[0057] c) Drilling design: Based on the actual site conditions, determine the basic type of borehole and design directional boreholes according to the occurrence of coal and rock strata;

[0058] d) Drilling equipment selection: Select the appropriate directional drilling rig based on parameters such as extraction purpose, formation conditions, downhole transportation conditions, roadway size, drilling depth, and borehole diameter;

[0059] e) Directional drilling construction: (1) Opening the hole; (2) Sealing the hole; (3) Directional drilling; (4) Measurement; (5) Correction; (6) Branching; (7) Slag removal; (8) Drilling out; (9) Shaft connection.

[0060] Furthermore, in this application, based on the needs of large-area gas control, the gas extraction tunnel formed by the rapid excavation of the TBM buys time and space for gas control, with an area of ​​32m². 2 Taking the gas extraction roadway as an example, due to the large roadway face, in order to optimize the mining layout and make reasonable use of the roadway, the boundary roadway can also be arranged in a three-dimensional "one roadway, multiple uses" configuration, with the upper layer for vehicles and pedestrians, and the lower layer for drainage and transportation. The TBM-driven gas extraction roadway, after its bottom is widened to increase the cross-section, can be used as a centralized transportation roadway, a main intake roadway, and a gas extraction roadway. In the TBM-driven gas extraction roadway, priority is given to arranging cross-layer drilling teams within the roadway, and pre-draining and eliminating outbursts from the upper coal seam in the coal seam roadway. Then, a large area of ​​coal seam groups is arranged within the roadway, combined with pressure relief cross-layer drilling and gas extraction work. During coal seam mining, the TBM-driven gas extraction roadway is used as a return air passage at the tail end of the coal face to carry out goaf retention work and solve the problem of gas accumulation in the tail roadway. The TBM-driven gas extraction roadway can simultaneously extract gas from both the upper and lower coal seams within the roadway, maximizing the use of the roadway's function.

[0061] In this invention, unless otherwise explicitly specified and limited, for example, it can be a fixed connection, a detachable connection, or an integral part; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two elements or an interaction between two elements. Unless otherwise explicitly limited, those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0062] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for controlling gas pollution in large areas, characterized in that, The steps are as follows: Delineate the boundaries of large-scale gas control areas; The TBM starts from the center of the boundary of the large-area gas control area and excavates the boundary tunnel along the boundary of the large-area gas control area; TBMs excavate connecting tunnels within the area enclosed by the boundary tunnels; Within the coal seam area enclosed by the connecting passageway and the boundary passageway, two directional drilling rigs are used to drill through boreholes in both directions. Gas extraction is carried out using fracturing extraction technology within the through borehole. The directional drilling rig is a kilometer-deep drilling rig; The width or length of the coal seam area enclosed by the connecting passageway and the boundary passageway meets the requirements for two kilometer-long drilling rigs to drill through holes in both directions. The width or length of the coal seam area enclosed by the connecting passageway and the boundary passageway is 600m; There are two TBMs excavating the boundary roadway. The two TBMs start from the center of the large area of ​​gas control, one excavating clockwise and the other counterclockwise, forming a U-shaped boundary roadway.

2. The method for controlling large-area gas according to claim 1, characterized in that: Before excavating the connecting tunnel, a launching shaft is set on the boundary of the area surrounded by the boundary tunnel, and a receiving shaft is set on the opposite side of the launching shaft and on the boundary of the area surrounded by the boundary tunnel; the TBM starts from the launching shaft and ends at the receiving shaft to excavate the connecting tunnel.

3. The method for controlling large-area gas according to claim 2, characterized in that: The launching well is used for TBM assembly, and the receiving well is used for TBM disassembly.

4. The method for controlling large-area gas according to claim 2, characterized in that: There is one or more connecting passageways. When there is one or more connecting passageways, each connecting passageway is evenly distributed within the area enclosed by the boundary passageway.

5. The method for controlling large-area gas according to claim 1, characterized in that: The fracturing and extraction process is segmented fracturing and extraction.

6. The method for controlling large-area gas according to claim 5, characterized in that: The segmented fracturing extraction method utilizes packers or bridge plugs to separate the segments.

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