An electrically controlled cracking and weakening device and method for thick hard top coal and hard roof

Abstract

The present invention discloses an electrically controlled fracturing and weakening device for thick hard top coal and hard roof, comprising a voltage excitation device, a guide device, an exciter, and at least one fracturing device; each fracturing device comprises a seaming device, a seaming device roller, a connecting rod, and a rolling bearing; the seaming device is fixedly connected to the seaming device roller, the seaming device roller is mounted on the connecting rod, and both ends of the connecting rod are fixedly connected to the rolling bearing; an excitation cavity is provided in the seaming device roller, the exciter is located in the excitation cavity, and the seaming device is provided with a plurality of fracturing control ports; by providing the excitation cavity and the seaming device in the seaming device roller, the seaming device is instantaneously excited under controllable voltage conditions under the action of the external voltage excitation device, thereby forming a three-dimensional weakened structure in the treatment layer using the electrically controlled fracturing method, destroying the overall structure of the overlying roof and top coal on the working surface, and reducing the strength of the rock mass and coal mass.

Description

Technical Field

[0001] The present invention relates to the technical field of coal development, and in particular to an electrically controlled fracturing and weakening device and method for thick hard top coal and hard roof. Background Art

[0002] my country is rich in coal resources, with thick and extra-thick coal seams accounting for a significant portion of both reserves and production. Fully mechanized top-coal caving (FCC) mining, due to its high production capacity, efficiency, and profitability, has become the preferred method for mining these seams.

[0003] With the deepening of coal mining and the use of top coal caving in thick coal layers, significant stress concentration in the coal seam roof and the difficulty of fully caving the hard top coal often lead to problems such as severe roof pressure disasters and low coal resource recovery rates during working face mining. To address these issues, existing treatment methods often use hydraulic fracturing and blasting. However, blasting has disadvantages such as harmful gases, uncontrollable energy, and difficulty in approving explosives. Hydraulic fracturing has disadvantages such as uncontrollable crack direction and scale and a high risk factor for high-pressure operations.

[0004] In view of the above defects, the designers of the present invention have studied and designed an electrically controlled fracturing and weakening device and method for thick hard top coal and hard roof, so as to improve the coordinated weakening of top coal and roof in fully mechanized caving mining and overcome the above technical problems. Summary of the Invention

[0005] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide an electrically controlled fracturing and weakening device and method for thick hard top coal and hard roof. An external voltage excitation device is used to induce an in-hole fracture device to produce directional fractures in the target layer, thereby transforming the coal and rock structure within the treatment range, reducing the strength of the coal and rock mass, and realizing the coordinated weakening of the top coal and roof in the fully-mechanized caving mining of thick hard coal seams.

[0006] The present invention adopts an electrically controlled fracturing and weakening device for thick hard top coal and hard roof, comprising a voltage excitation device (9), a guide device (5), an exciter and at least one fracturing device, each of the fracturing devices comprising a seam-forming device (4), a seam-forming device roller (6), a connecting rod (7) and a rolling bearing (14), the seam-forming device (4) being fixedly connected to the seam-forming device roller (6), the seam-forming device roller (6) being mounted on the connecting rod (7), the two ends of the connecting rod (7) being fixedly connected to the rolling bearing (14), an excitation cavity (11) being provided in the seam-forming device roller (6), the exciter being located in the excitation cavity (11), and the seam-forming device (4) being provided with a plurality of fracturing control ports (15);

[0007] Furthermore, the rolling bearing (14) adopts a rolling gear bearing, and the rotation of the gear drives the rotation of the seam-forming device (4), and the rotation angle is calculated by the number of rotating teeth of the gear to achieve the precise orientation of the fracture control port (15), that is, to achieve the control of the directional fracture range (12);

[0008] Furthermore, the seaming device (4) is evenly provided with four fracture control openings (15) in the circumferential direction;

[0009] Furthermore, the voltage excitation device (9) is connected to the fracturing device via an electric control line (13);

[0010] Furthermore, the seaming device roller (6) can store 50 to 100 seaming devices (4);

[0011] The present invention adopts an electric controlled cracking and weakening method for thick hard top coal and hard roof.

[0012] Step S1, drilling (10) construction: selecting a drilling rig according to the treatment scope requirements, and using the drilling rig to complete the directional drilling (10) construction;

[0013] Furthermore, the directional drilling machine's measurement-while-drilling performance is utilized to obtain the three-dimensional spatial trajectory information of the borehole (10); and by adjusting the working surface angle, the actual trajectory of the borehole (10) is ensured to meet the design requirements of the borehole (10), thereby completing the construction of the directional long borehole (10);

[0014] Step S2, transporting the fracturing device in the hole: installing the fracturing device (4) into the fracturing device roller (6), and transporting the installed fracturing device to a designated position of the borehole (10) through a drilling rig, and connecting the fracturing device to the voltage excitation device (9) via an electric control line (13);

[0015] Furthermore, a plurality of seaming devices (4) are loaded into a plurality of seaming device rollers (6), the plurality of seaming device rollers (6) are connected via a connecting rod (7), and the seaming device rollers (6) are lowered into the borehole (10) at once via a drilling machine;

[0016] Alternatively, multiple seaming devices (4) are loaded into a single large-capacity seaming device roller (6), and the seaming device roller (6) is fed into a designated position of a drilling hole (10) by a drilling machine;

[0017] Step S3, control of the directional fracturing range (12): the rolling bearing (14) adopts a rolling gear bearing, and the rotation of the gear of the rolling gear bearing is used to realize the rotation of the connecting rod (7) and the seaming device roller (6), thereby driving the seaming device (4) to rotate, and the rotation angle of the seaming device (4) is calculated by the rotation angle of the bearing, thereby realizing the precise orientation of the fracturing control port (15), that is, realizing the control of the directional fracturing range (12);

[0018] Step S4, electric-controlled fracturing construction: after the control line angle adjustment is completed, the rated voltage of the electric-controlled fracturing device is set according to the requirements, and the one-time segmented fracturing transformation of the drill hole (10) is triggered by the voltage excitation device (9), thereby completing the fracturing construction;

[0019] Furthermore, under the action of the voltage excitation device (9), the excitation chamber (11) excites the cracking device (4) to perform a fracturing operation, thereby forming a crack (8). The range of the crack (8) is the directional fracturing range (12), thereby achieving a one-time segmented fracturing transformation of the long borehole (10);

[0020] Alternatively, under the action of the voltage excitation device (9), the exciter located in the excitation chamber (11) excites the seam-inducing device (4) to perform a fracturing operation, thereby achieving a first-stage fracturing modification and forming a first-stage fissure (8); then, the seam-inducing device roller (6) is dragged to the next fracturing stage by a drilling rig, and the second-stage fracturing modification is achieved by the voltage excitation device (9) to form a second-stage fissure, and the entire fracturing operation is completed by multiple cycles;

[0021] Furthermore, 50 to 100 seam-forming devices (4) are stored in the seam-forming device roller (6);

[0022] Step S5, in-hole equipment output: After completing the fracturing modification construction of the entire designed section in the hole, use the drilling rig to withdraw all the equipment in the hole to complete the construction.

[0023] Compared with the prior art, the advantages of the present invention are as follows:

[0024] 1. The electrically controlled fracturing device and method of the present invention achieves instantaneous activation of the cracking device under controllable voltage conditions, effectively weakening thick and hard top coal and roof slabs. Under the action of the external voltage activation device, multiple activations of a single fracturing segment can be achieved, effectively increasing cracks in the top coal and roof slab and reducing overall strength.

[0025] 2. The seam-forming device roller of the present invention is provided with an excitation chamber, which can promote the precise control of the energy release direction of the seam-forming device and improve the cracking effect of the top coal and roof;

[0026] 3. The present invention can realize the one-time installation of the seam-inducing roller at different intervals, thus realizing the one-time segmented fracturing transformation of a long borehole. It can also use a single seam-inducing roller to install the seam-inducing device in large capacity, and use a drilling rig to carry out drag-type segmented and point-by-point stimulation of fracturing and seaming.

[0027] 4. The excitation chamber is activated by an external voltage excitation device to achieve the purpose of electrically controlled cracking. The operation process is simple and safe. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly describes the drawings required for the specific embodiments or the description of the prior art. Similar elements or parts are generally identified by similar reference numerals throughout the drawings. Elements or parts in the drawings are not necessarily drawn to scale.

[0029] Figure 1 A cross-sectional diagram of the drilling arrangement;

[0030] Figure 2 This is a schematic diagram of simultaneous fracturing modification of multiple fracturing devices;

[0031] Figure 3 Schematic diagram of simultaneous fracturing modification of a single fracturing device;

[0032] Figure 4 is a cross-sectional view of the fracturing device;

[0033] Figure 5 This is the structural diagram of the fracturing device.

[0034] In the attached figure, 4 is a seam-inducing device; 5 is a guide device; 6 is a roller of the seam-inducing device; 7 is a connecting rod; 8 is a crack; 9 is a voltage excitation device; 10 is a drilling hole; 11 is an excitation chamber; 12 is a directional fracturing range; 13 is an electric control line; 14 is a rolling bearing; and 15 is a fracturing control port. DETAILED DESCRIPTION

[0035] The following embodiments of the technical solution of the present invention will be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention and are therefore only examples and are not intended to limit the scope of protection of the present invention.

[0036] It should be noted that, unless otherwise specified, the technical or scientific terms used in this application should have the common meanings understood by those skilled in the art to which the present invention belongs.

[0037] like Figure 1-5 As shown, an electrically controlled fracturing and weakening device for thick hard top coal and hard roof comprises a voltage excitation device 9, a guide device 5, an exciter, and at least one fracturing device. Each fracturing device comprises a seaming device 4, a seaming device roller 6, a connecting rod 7, and a rolling bearing 14. The seaming device 4 is fixedly connected to the seaming device roller 6, which is mounted on the connecting rod 7. Both ends of the connecting rod 7 are fixedly connected to the rolling bearing 14. An excitation cavity 11 is provided in the seaming device roller 6. The exciter is located in the excitation cavity 11. The seaming device 4 has four fracturing control ports 15 evenly arranged around the circumference. The voltage excitation device 9 is connected to the fracturing device via an electric control line 13.

[0038] In order to facilitate the control of the directional fracturing range 12, the rolling bearing 14 adopts a rolling gear bearing. The rotation of the gear drives the rotation of the seam-forming device 4. The rotation angle is calculated by the number of teeth of the gear to achieve the precise orientation of the fracturing control port 15.

[0039] In order to facilitate the cracking construction, 50 to 100 cracking devices 4 are stored in the cracking device roller 6;

[0040] An electrically controlled cracking and weakening method for thick hard top coal and hard roof.

[0041] Step S1, drilling 10 construction: select a drilling rig according to the treatment scope requirements, and use the drilling rig to complete the directional drilling 10 construction;

[0042] Furthermore, the directional drilling rig's measurement-while-drilling performance is utilized to obtain the three-dimensional trajectory information of the borehole 10; and by adjusting the working face angle, the actual trajectory of the borehole 10 is ensured to meet the design requirements of the borehole 10, thereby completing the construction of the directional long borehole 10;

[0043] Step S2, transporting the fracturing device in the hole: the fracturing device 4 is installed in the fracturing device roller 6, and the installed fracturing device is transported to the designated position of the borehole 10 through the drilling rig, and the fracturing device is connected to the voltage excitation device 9 via the electric control line 13;

[0044] Furthermore, multiple seaming devices 4 are loaded into multiple seaming device rollers 6, and the multiple seaming device rollers 6 are connected by connecting rods 7, and the seaming device rollers 6 are lowered into the borehole 10 at once by a drilling machine;

[0045] Alternatively, multiple seamers 4 are loaded into a single large-capacity seamer roller 6, and the seamer roller 6 is fed into a designated position of a drill hole 10 by a drilling machine;

[0046] Step S3, controlling the directional fracturing range 12: The rolling bearing 14 is a rolling gear bearing. The rotation of the rolling gear bearing rotates the connecting rod 7 and the seam-inducing roller 6, thereby driving the seam-inducing roller 4 to rotate. The rotation angle of the seam-inducing roller 4 is calculated based on the rotation angle of the bearing, thereby achieving precise orientation of the fracturing control port 15, thereby achieving control of the directional fracturing range 12.

[0047] Step S4, electric-controlled fracturing construction: After the control line angle adjustment is completed, the rated voltage of the electric-controlled fracturing device is set as required, and the voltage excitation device 9 is used to trigger the one-time segmented fracturing transformation of the borehole 10 to complete the fracturing construction;

[0048] Furthermore, under the action of the voltage excitation device 9, the exciter located in the excitation chamber 11 excites the cracking device 4 to perform a fracturing operation, thereby forming a crack 8. The range of the crack 8 is the directional fracturing range 12, thereby achieving a one-time segmented fracturing transformation of the long borehole 10.

[0049] Alternatively, under the action of the voltage excitation device 9, the excitation chamber 11 excites the seam-inducing device 4 to perform a fracturing operation, thereby achieving a first-stage fracturing reformation and forming a first-stage fissure 8; the seam-inducing device roller 6 is then dragged to the next fracturing stage by a drilling rig, and the voltage excitation device 9 is used to perform a second-stage fracturing reformation and form a second-stage fissure 8, and the entire fracturing operation is completed through multiple cycles;

[0050] Furthermore, 50 to 100 seam-forming devices 4 are stored in the seam-forming device roller 6;

[0051] Step S5, in-hole equipment output: After completing the fracturing modification construction of the entire designed section in the hole, use the drilling rig to withdraw all the equipment in the hole to complete the construction.

[0052] The working principle of the present invention is as follows: an electrically controlled fracturing and weakening device and method for thick and hard top coal and hard roof. By providing an excitation chamber and a fracturing device in the fracturing device roller, the fracturing device is instantaneously excited under controllable voltage conditions under the action of an external voltage excitation device. The electrically controlled fracturing method is used to form a three-dimensional weakening structure in the treatment layer, destroying the overall structure of the overlying roof and top coal on the working face, reducing the strength of the rock and coal body, shortening the working face pressure step, and increasing the frequency of roof breaking disturbance loads. The superposition of the static load stress increases the top coal breaking stress, improves the degree of top coal fracture under the disturbance effect, integrates the fracturing and fracture-forming effect of the top coal itself, and realizes the coordinated forced caving of mine pressure control and top coal weakening transformation.

[0053] 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 above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and description of the present invention.

Claims

1. An electrically controlled fracturing and weakening device for thick hard top coal and hard roof, comprising a voltage excitation device (9), a guide device (5), an exciter, and at least one fracturing device; characterized in that: Each of the fracturing devices comprises a seaming device (4), a seaming device roller (6), a connecting rod (7) and a rolling bearing (14); the seaming device (4) is fixedly connected to the seaming device roller (6); the seaming device roller (6) is mounted on the connecting rod (7); both ends of the connecting rod (7) are fixedly connected to the rolling bearing (14); an excitation cavity (11) is provided in the seaming device roller (6); the exciter is located in the excitation cavity (11); the seaming device (4) is provided with a plurality of fracturing control ports (15); the rolling bearing (14) adopts a rolling gear bearing, which drives the rotation of the seaming device (4) by the rotation of the gear, and the precise orientation of the fracturing control port (15) is achieved by calculating the rotation angle by the number of rotating teeth of the gear.

2. The electrically controlled fracturing and weakening device for thick hard top coal and hard roof according to claim 1, characterized in that: The seam-causing device (4) is evenly provided with four crack control directions in the circumferential direction.

3. The electrically controlled fracturing and weakening device for thick hard top coal and hard roof according to claim 2, characterized in that: The voltage excitation device (9) is connected to the fracturing device via an electric control line (13).

4. The electrically controlled fracturing and weakening device for thick hard top coal and hard roof according to claim 3, characterized in that: The seaming device roller (6) stores 50 to 100 seaming devices (4).

5. The electrically controlled fracturing method of the electrically controlled fracturing and weakening device according to any one of claims 1 to 4, comprising the following steps: Step S1, drilling (10) construction: selecting a drilling rig according to the treatment scope requirements, and using the drilling rig to complete the directional drilling (10) construction; Step S2, transporting the fracturing device in the hole: installing the fracturing device (4) into the fracturing device roller (6), and transporting the installed fracturing device to a designated position of the borehole (10) through a drilling rig, and connecting the fracturing device to the voltage excitation device (9) via an electric control line (13); Step S3, control of the directional fracturing range (12): the rolling bearing (14) adopts a rolling gear bearing, and the rotation of the gear of the rolling gear bearing is used to realize the rotation of the connecting rod (7) and the seaming device roller (6), thereby driving the seaming device (4) to rotate, and the rotation angle of the seaming device (4) is calculated by the rotation angle of the bearing, thereby realizing the precise orientation of the fracturing control port (15), that is, realizing the control of the directional fracturing range (12); Step S4, electric-controlled fracturing construction: after the control line angle adjustment is completed, the rated voltage of the electric-controlled fracturing device is set according to the requirements, and the one-time segmented fracturing transformation of the drill hole (10) is triggered by the voltage excitation device (9), thereby completing the fracturing construction; Step S5, in-hole equipment output: After completing the fracturing modification construction of the entire designed section in the hole, use the drilling rig to withdraw all the equipment in the hole to complete the construction.

6. The electrically controlled fracturing method according to claim 5, characterized in that: In step S2, multiple seaming devices (4) are loaded into multiple seaming device rollers (6), and the multiple seaming device rollers (6) are connected by connecting rods (7). The seaming device rollers (6) are lowered into the borehole (10) at one time by a drilling machine.

7. The electrically controlled fracturing method according to claim 5, wherein: In step S2, multiple seamers (4) are loaded into a single large-capacity seamer roller (6), and are fed into the seamer roller (6) to a designated position of a drill hole (10) through a drilling machine.

8. The electrically controlled fracturing method according to claim 5, wherein: In step S4, under the action of the voltage excitation device (9), the exciter located in the excitation chamber (11) excites the cracking device (4) to perform a fracturing operation, thereby forming a crack (8). The range of the crack (8) is the directional fracturing range (12), thereby achieving a one-time segmented fracturing transformation of the long borehole (10).

9. The electrically controlled fracturing method according to claim 5, wherein: In step S4, under the action of the voltage excitation device (9), the excitation chamber (11) excites the seam-inducing device (4) to perform a fracturing operation, thereby achieving a first-stage fracturing modification and forming a first-stage fissure (8); then, the seam-inducing device roller (6) is dragged to the next fracturing stage by a drilling rig, and a second-stage fracturing modification is achieved by the voltage excitation device (9), thereby forming a second-stage fissure (8), and the entire fracturing construction is completed through multiple cycles.

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