Directional blasting rings for simultaneous construction of gas drainage channels and their applications

Abstract

This invention discloses a directional blasting ring for simultaneously constructing gas drainage channels and its application. The directional blasting ring uses a semi-circular steel structure as a support, which consists of an outer arc steel plate and an inner arc steel plate, forming an axially continuous hollow cavity between them. A directional opening is formed on the side of the support using the concave shape of the inner arc steel plate. A rock stratum extraction pipe is inserted axially into the hollow cavity, forming a rock stratum extraction channel. This channel, located within the hollow cavity, is protected by the support. A charge is placed in the concave shape of the inner arc steel plate, allowing the charge to gain focused energy and enabling directional blasting towards the target coal seam through the directional opening formed by the concave shape. This invention effectively improves gas control efficiency by simultaneously constructing gas drainage channels.

Description

Technical Field

[0001] This invention relates to the field of gas control technology, and more specifically to a directional blasting ring that can simultaneously construct a gas extraction channel, and its application in coal seam gas extraction. Background Technology

[0002] Coal seam gas is the primary safety threat to underground engineering. Achieving safe co-mining of coal and gas requires depressurization and permeability enhancement of the coal seam, with blasting fracturing being a widely used method. However, when using existing technology to blast in hard coal or rock strata, the uncontrolled release of explosive energy can lead to excessive crushing or the creation of disordered fractures in the surrounding coal and rock mass. The direct consequence is that the blasted borehole itself collapses and becomes blocked, rendering it unusable as an effective extraction channel. This not only renders the previously constructed boreholes and pipelines completely unusable, resulting in severe economic losses, but also prevents the effective collection and extraction of coal seam gas after permeability enhancement, creating a dilemma of enhanced permeability without flow or flow without extraction. Ultimately, the remaining gas accumulation hazard will severely restrict subsequent safe production. Summary of the Invention

[0003] To overcome the shortcomings of the existing technology, this invention provides a directional blasting ring that can simultaneously construct a gas drainage channel and its application, aiming to effectively coordinate the contradiction between blasting permeability enhancement and channel maintenance. It achieves efficient directional fracturing while forming a gas drainage channel, realizing the simultaneous execution of directional blasting and the construction of the drainage channel, and effectively improving the efficiency of gas control.

[0004] To achieve its objectives, the present invention employs the following technical solution:

[0005] The directional blasting ring of this invention, which can simultaneously construct a gas extraction channel, is characterized by the following: the directional blasting ring uses a semi-circular steel structure as a support, which is composed of an outer arc steel plate and an inner arc steel plate, and forms an axially penetrating hollow cavity between the outer and inner arc steel plates. The support utilizes the concave arc of the inner arc steel plate to form a directional opening on the side where the inner arc steel plate is located. A rock stratum extraction pipe is inserted axially into the hollow cavity, forming a rock stratum extraction channel. The rock stratum extraction channel within the hollow cavity is protected by the support. A charge is placed in the concave arc of the inner arc steel plate, so that the charge gains focused energy using the concave arc of the inner arc steel plate, and directional blasting is carried out towards the target coal seam using the directional opening formed by the concave arc.

[0006] The directional blasting ring of the present invention, which can simultaneously construct gas extraction channels, is characterized by the following: a steel frame is set between the outer arc steel plate and the inner arc steel plate, and the hollow cavity of the support body is divided into independent cavities along the circumference by the steel frame. Each rock stratum extraction pipe is set in each independent cavity in a corresponding manner to form multiple rock stratum extraction channels.

[0007] The directional blasting ring of the present invention, which can simultaneously construct a gas extraction channel, is also characterized by the fact that the rock stratum extraction pipe is a plastic pipe with a screen.

[0008] The coal seam gas extraction using the directional blasting ring that can simultaneously construct gas extraction channels according to this invention is carried out according to the following steps:

[0009] Step 1: In the roof strata above the target coal seam, drill holes parallel to the target coal seam, ensuring that the distance between the roof strata drill holes and the coal seam roof is no more than 0.5 meters, and drill holes along the coal seam in the target coal seam.

[0010] Step 2: Place the directional blasting ring into the borehole in the roof rock stratum, with its opening facing the target coal seam, so that the explosive charge is in the section of the borehole in the roof rock stratum parallel to the target coal seam, and the rock stratum extraction pipe is protected in the support body.

[0011] Step 3: Connect the rock strata extraction pipe and the coal seam borehole to the main extraction pipe through the corresponding extraction branch pipes, and seal the pipe openings of each extraction branch pipe to form a sealed section.

[0012] Step 4: Detonate the explosive charge and immediately start the extraction system after blasting. Use the three-dimensional extraction network consisting of the main extraction pipe, branch extraction pipes, rock strata extraction pipes, and boreholes along the coal seam to extract coal seam gas.

[0013] The method for coal seam gas extraction of the present invention is also characterized in that: the outer diameter of the outer arc steel plate matches the diameter of the borehole in the roof rock stratum, so that the directional blasting ring is firmly fixed in the borehole in the roof rock stratum.

[0014] The method for coal seam gas extraction of the present invention is characterized in that the borehole in the roof strata is located within a range of 0.3 meters to 0.8 meters above the roof interface of the target coal seam.

[0015] The method for coal seam gas extraction of the present invention is also characterized in that: the borehole along the coal seam is set to one or more layers according to the thickness of the target coal seam.

[0016] Compared with existing technologies, the beneficial effects of this invention are reflected in:

[0017] 1. This invention solves the long-standing contradiction between blasting for increased permeability and borehole shape preservation in coal seam gas drainage. It places an integrated device that combines focused blasting and channel protection functions in the roof strata. While utilizing the focused blasting effect to directionally fracture the coal seam and form an efficient fracture network, its robust support structure withstands the reaction force of the explosion, ensuring that the blast hole is completely transformed into a stable drainage channel. This achieves continuous and efficient drainage after blasting, which not only significantly improves gas drainage efficiency but also avoids repeated drilling, comprehensively reducing operating costs and safety risks.

[0018] 2. This invention applies the destructive force of blasting energy to the rock strata in a predetermined direction, forming a highly efficient network of penetrating fractures in the coal seam. At the same time, it ensures that the boreholes and channels formed after blasting remain stable and unobstructed, thereby achieving efficient gas extraction. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the energy-concentrating device structure and directional blasting in this invention;

[0020] Figure 2 This is a side view schematic diagram of the energy-concentrating device applied to coal seam gas extraction in this invention;

[0021] Figure 3 This is a top view schematic diagram of the energy-concentrating device applied to coal seam gas extraction in this invention;

[0022] Figure 4 This is a front view schematic diagram of the energy-concentrating device applied to coal seam gas extraction in this invention;

[0023] Figure 5 This is a schematic diagram illustrating the effect of the energy-concentrating device applied to coal seam gas extraction blasting in this invention.

[0024] The following are the labels in the diagram: 1 Outer arc steel plate, 2 Steel frame, 3 Rock stratum extraction pipe, 4 Inner arc steel plate, 5 Explosive charge, 6 Target coal seam, 7 Outburst suppression outline, 8 Directional drilling rig, 9 Directional blasting ring, 10 Borehole along coal seam, 11 Extraction pump room, 12 Extraction branch pipe, 13 Tunnel outline, 14 Sealing section, 15 Extraction main pipe, 16 Roof rock stratum borehole. Detailed Implementation

[0025] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0026] See Figure 1 and Figure 2 In this embodiment, the directional blasting ring that can simultaneously construct the gas extraction channel uses a semi-circular steel structure as the support. The support consists of an outer arc steel plate 1 and an inner arc steel plate 4, and a hollow cavity is formed between the outer arc steel plate 1 and the inner arc steel plate 4. The support uses the concave arc of the inner arc steel plate 4 to form a directional opening on the side where the inner arc steel plate 4 is located. A rock stratum extraction pipe 3 is inserted axially into the hollow cavity, forming a rock stratum extraction channel. The rock stratum extraction channel 3 in the hollow cavity is protected by the support. A charge 5 is placed in the concave arc of the inner arc steel plate 4, so that the charge 5 can obtain energy by utilizing the concave arc of the inner arc steel plate 4, and directional blasting is carried out towards the side where the target coal seam 6 is located by utilizing the directional opening formed by the concave arc.

[0027] like Figure 1As shown, in this embodiment, steel frames 2 are set between the outer arc steel plate 1 and the inner arc steel plate 4. The steel frames 2 divide the hollow cavity of the support body into independent cavities along the circumference. Rock extraction pipes 3 are set in each independent cavity to form multiple rock extraction channels. The rock extraction pipes 3 are plastic pipes with screen holes.

[0028] This embodiment utilizes Figure 1 The directional blasting ring shown, which can simultaneously construct gas drainage channels, is used for coal seam gas drainage according to the following steps, see [link to relevant documentation]. Figure 2 , Figure 3 , Figure 4 and Figure 5 .

[0029] Step 1: As Figure 2 As shown, a directional drilling rig 8 is set up in the tunnel working face. The directional drilling rig 8 is used to drill a roof rock stratum borehole 16 in the roof rock stratum above the target coal seam, parallel to the target coal seam 6, so that the distance between the roof rock stratum borehole 16 and the coal seam roof is no more than 0.5 meters. A coal seam borehole 10 is drilled in the target coal seam 6.

[0030] Step 2: As Figure 2 , Figure 3 and Figure 4 As shown, the directional blasting ring 9 is placed in the roof stratum borehole 16 with its opening facing the target coal seam 6. The explosive charge 5 is positioned within the section of the roof stratum borehole 16 parallel to the target coal seam 6, and the stratum extraction pipe 3 is enclosed within the support structure. A coal seam drilling hole 10 is constructed in the target coal seam 6, and a gas extraction pipeline is installed. The coal seam drilling hole 10 consists of one or more rows depending on the thickness of the target coal seam. Figure 2 The diagram shows two rows; outside the tunnel outline 13, the outburst suppression outline 7 is drawn, and the coal seam borehole 10 and the roof strata borehole 16 are both distributed within the outburst suppression outline 7.

[0031] Step 3, as follows Figure 3 , Figure 4 and Figure 5 As shown, the rock strata extraction pipe 3 and the coal seam borehole 10 are respectively connected to the extraction main pipe 15 through the corresponding extraction branch pipes 12, and the pipe openings of each extraction branch pipe 12 are sealed to form the sealing section 14.

[0032] Step 4: Detonate the explosive charge 5, and after the blasting is completed, start the extraction system set in the extraction pump room 11. Use the three-dimensional extraction network consisting of the extraction main pipe 15, extraction branch pipes 12, rock stratum extraction pipes 3 and coal seam boreholes 10 to extract coal seam gas.

[0033] In practice, the corresponding technical measures also include:

[0034] The outer diameter of the outer arc steel plate 1 matches the diameter of the borehole 16 in the roof rock layer, so that the directional blasting ring 9 is firmly fixed in the borehole 16 in the roof rock layer; the borehole 16 in the roof rock layer is set within a range of 0.3 meters to 0.8 meters above the roof interface of the target coal seam.

[0035] The axial orientation of the roof rock borehole 16 is kept within ±3° of the target coal seam 6. The borehole trajectory is dynamically adjusted by the real-time attitude monitoring system of the directional drilling rig 8 to ensure that the fracture network formed by blasting is consistent with the coal seam orientation, thereby maximizing the fracturing and permeability enhancement. If there are secondary folds or small faults in the target coal seam, the borehole orientation can be finely adjusted within ±5° according to the geological survey results to avoid structurally weak zones and ensure borehole stability.

[0036] After the drilling of the top rock layer 16 is completed, high-pressure air (pressure 0.6-0.8MPa) is used to clean the rock powder in the hole to ensure that the hole wall is smooth and free of debris, so as to avoid the rock powder affecting the installation accuracy of the directional blasting ring 9.

[0037] In this invention, the directional blasting ring embodies the synergistic effect of "directional energy focusing" and "structural pressure bearing," successfully unifying the two originally opposing processes of "blasting" and "extraction" in the same space and time sequence, and achieving the ultimate goal of "blasting without destroying and breaking while extracting."

[0038] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the present invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A directional blasting ring capable of simultaneously constructing a gas drainage channel, characterized in that: The directional blasting ring is supported by a semi-circular steel structure. The support is composed of an outer arc steel plate (1) and an inner arc steel plate (4), and a hollow cavity is formed between the outer arc steel plate (1) and the inner arc steel plate (4) in an axial direction. The support forms a directional opening on the side where the inner arc steel plate (4) is located using the concave arc of the inner arc steel plate (4). A rock stratum extraction pipe (3) is inserted into the hollow cavity along the axial direction, forming a rock stratum extraction channel. The rock stratum extraction channel in the hollow cavity is protected by the support. A charge (5) is placed in the concave arc of the inner arc steel plate (4), so that the charge (5) can obtain energy by using the concave arc of the inner arc steel plate (4), and directional blasting is carried out towards the target coal seam using the directional opening formed by the concave arc.

2. The directional blasting ring for synchronously constructing gas drainage channels according to claim 1, characterized in that: in A steel frame (2) is set between the outer arc steel plate (1) and the inner arc steel plate (4). The steel frame (2) divides the hollow cavity of the support into independent cavities along the circumference. Each rock stratum extraction pipe (3) is set in each independent cavity to form multiple rock stratum extraction channels.

3. The directional blasting ring for synchronously constructing gas drainage channels according to claim 2, characterized in that: The rock strata extraction pipe (3) is a plastic pipe with a screen.

4. A method for coal seam gas extraction using the directional blasting ring capable of simultaneously constructing gas extraction channels as described in claim 1, characterized in that: Follow these steps: Step 1: In the roof strata above the target coal seam, construct a roof strata borehole (16) parallel to the target coal seam, such that the distance between the roof strata borehole (16) and the coal seam roof is no more than 0.5 meters, and construct a coal seam borehole (10) in the target coal seam. Step 2: Place the directional blasting ring into the borehole (16) of the roof rock stratum, with its opening facing the target coal seam (6), so that the explosive charge (5) is in the section of the borehole (16) of the roof rock stratum parallel to the target coal seam (6), and so that the rock stratum extraction pipe (3) is protected in the support body. Step 3: Connect the rock stratum extraction pipe (3) and the coal seam borehole (10) to the extraction main pipe (15) through the corresponding extraction branch pipe (12), and seal the pipe opening section of each extraction branch pipe (12) to form a sealed section (14). Step 4: Detonate the explosive charge (5), and after the blasting is completed, start the extraction system to extract coal seam gas using a three-dimensional extraction network consisting of the extraction main pipe (15), extraction branch pipes (12), rock stratum extraction pipes (3), and boreholes along the coal seam (10).

5. The method for coal seam gas extraction according to claim 4, characterized in that: The outer diameter of the outer arc steel plate (1) matches the diameter of the borehole (16) in the top stratum rock, so that the directional blasting ring (9) is firmly fixed in the borehole (16) in the top stratum rock.

6. The method for coal seam gas extraction according to claim 4, characterized in that: The borehole (10) along the coal seam is set to one or more layers depending on the thickness of the target coal seam.

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