Mining system and method

Abstract

The present application provides a mining system and method. The system includes: a mechanical reaming and coal breaking module including: a drill rod rotating device, a drill rod and a reaming and slotting drill bit; the drill rod rotating device, the drill rod and the reaming and slotting drill bit are connected in sequence to perform rotary cutting, reaming and slotting operations on the coal seam in the coal mining borehole; the gas lift reverse circulation lifting module uses an air compressor to transport the coal gas and water mixture through the inner tube channel of the double-wall drill rod to the coal gas and water separation module; the abrasive jet hydraulic coal breaking module includes a fracturing vehicle, a drill rod rotating device, a drill rod and a jet tool string, which are connected in sequence to mine the coal seam. The embodiment of the present application can effectively avoid the safety risks caused by coal and gas outbursts, rock bursts or water disasters in underground mining by combining mechanical reaming and hydraulic coupling coal mining. Due to the mobility of ground supporting facilities, it can adapt well to various coal seam occurrence states, and water jet coal breaking can effectively prevent explosions and improve the safety of the mining process.

Description

Technical Field

[0001] The present application relates to the technical field of coal gas dual resource co-exploitation, and in particular to an exploitation system and method. Background Art

[0002] Coal is a non-renewable energy source and coexists with coalbed methane. With the continuous increase in mining intensity and demand, the issue of whether safe, efficient and high-recovery integrated mining of coal resources and coalbed methane resources can be achieved has gradually received attention. In terms of coal recovery rate, there is a serious legacy of coal corners in coal mines, and the storage of coal corners is considerable. However, the current mining technology of coal corners is difficult and the mining technology is immature. The conventional wall mining and tunneling technology are limited in scope of application. The working face is short and has large changes. The mechanization of the comprehensive mining and caving equipment used is difficult, and the installation, removal and relocation of working face equipment are frequent. This leads to complex mining processes, high coal mining costs per ton, and economic irrationality. Deep mining is difficult and costly, and not only faces complex geological structural conditions and unclear occurrence conditions, but also faces difficulties such as high ground stress, high ground temperature and high osmotic pressure. In terms of coalbed methane extraction, the coalbed methane pre-extraction technology in the early stage of conventional coal resource mining needs to be coordinated with the progress of coal mining in terms of extraction space and time. Under the rigid requirement of reducing gas content to meet the conditions for underground mining, it is also necessary to reduce the extraction time as much as possible and match the process requirements of extraction before construction, extraction before excavation, and extraction before mining, which leads to an increasing contradiction between the time and space succession of coalbed methane extraction and coal mine excavation. Summary of the invention

[0003] In view of this, the purpose of this application is to provide a mining system and method.

[0004] Based on the above objectives, the present application provides a mining system, comprising:

[0005] Mechanical hole expansion coal breaking module, gas lift reverse circulation lifting module, abrasive jet hydraulic coal breaking module and coal gas and water separation module;

[0006] The mechanical hole-reaming and coal-breaking module comprises: a drill rod rotating device, a drill rod and a hole-reaming and slotting drill bit; the drill rod rotating device, the drill rod and the hole-reaming and slotting drill bit are connected in sequence to perform rotary cutting, hole-reaming and slotting operations on the coal seam in the coal mining borehole;

[0007] The gas lift reverse circulation lifting module includes an air compressor and a double-wall drill pipe, so that the air compressor is used to transport the gas-water mixture to the gas-water separation module through the inner pipe channel of the double-wall drill pipe;

[0008] The abrasive jet hydraulic coal breaking module comprises: the drill rod rotating device, the fracturing vehicle, the drill rod and the jet tool string; the fracturing vehicle, the drill rod rotating device, the drill rod and the jet tool string are connected in sequence to mine the coal seam.

[0009] In a possible implementation, the mechanical reaming and coal breaking module further includes: a drilling fluid truck and a high-pressure pipeline;

[0010] The drilling fluid vehicle is arranged on the ground and connected to the coal mining borehole through the high-pressure pipeline;

[0011] The drill rod rotating device is arranged at the wellhead of the coal mining borehole.

[0012] In a possible implementation, the gas lift reverse circulation lifting module further includes: a single-wall drill pipe, a gas-liquid mixer and a roller drill bit;

[0013] The air compressor is arranged on the ground and connected to the double-wall drill pipe through a high-pressure pipeline;

[0014] The gas-liquid mixer is arranged at the lower end of the double-wall drill pipe and is connected to the single-wall drill pipe;

[0015] The single-wall drill rod is connected to the roller drill bit.

[0016] In a possible implementation, the abrasive jet hydraulic coal breaking module further includes: a mixing vehicle, an abrasive tank vehicle and a clean water tank;

[0017] The abrasive tank truck and the clean water tank are respectively connected to the mixing truck;

[0018] The mixing vehicle is connected to the fracturing vehicle to supply mixed abrasive;

[0019] The fracturing truck is connected to the drill pipe via a high-pressure hose to supply high-pressure abrasive.

[0020] In a possible implementation, the gas-water separation module includes: a gas-water separator and a sedimentation tank;

[0021] The gas-water separator is connected to the double-wall drill pipe;

[0022] The gas-water separator is connected to the sedimentation tank.

[0023] In a possible implementation, a water baffle is provided in the sedimentation tank;

[0024] A water pump is arranged at the bottom of the sedimentation tank to pump the water in the sedimentation tank to the coal mining borehole.

[0025] Based on the same inventive concept, an embodiment of the present application further provides a mining method, characterized in that it is applied to the mining system according to any one of claims 1 to 6, and the method comprises:

[0026] Use the mechanical hole-reaming and coal-breaking module to perform rotary cutting, hole-reaming and slotting operations on the coal seams in the pre-built coal mining boreholes;

[0027] The gas-water mixture formed after rotary cutting, reaming and slotting operations is transported to the gas-water separation module by using the gas lift reverse circulation lifting module;

[0028] Using the abrasive jet hydraulic coal breaking module to perform jet coal breaking operation on the coal seam;

[0029] The gas-water mixture formed after the jet coal breaking operation is transported to the gas-water separation module by using the gas lift reverse circulation lifting module;

[0030] The coal gas and water separation module is used to separate the coal gas and water mixture to obtain coal, coalbed methane and water.

[0031] In a possible implementation, the gas lift reverse circulation lifting module is used to transport the coal gas-water mixture formed after the jet coal breaking operation to the coal gas-water separation module, including:

[0032] The air compressor in the gas lift reverse circulation lifting module is used to deliver high-pressure air to the annular gap between the inner and outer pipe walls of the double-wall drill pipe, and the gas is delivered to the gas-water mixture in the inner pipe of the double-wall drill pipe through the gas-liquid mixer in the gas lift reverse circulation lifting module. The gas-water mixture is transported to the gas-water separation module in turn through the inner pipe channels of the single-wall drill pipe in the gas lift reverse circulation lifting module and the double-wall drill pipe in the gas lift reverse circulation lifting module by reverse circulation.

[0033] In a possible implementation, the abrasive jet hydraulic coal breaking module is used to perform jet coal breaking on the coal seam, including:

[0034] Using the fracturing vehicle in the abrasive jet hydraulic coal breaking module to pressurize the water-sand in the mixing vehicle in the abrasive jet hydraulic coal breaking module;

[0035] The pressurized water sand is transported to the jet tool string in the abrasive jet hydraulic coal breaking module through a high-pressure hose;

[0036] The jet tool string is used to perform abrasive jet rotary cutting on the coal seam and withdraw coal breaking mining.

[0037] In a possible implementation, the mining of the coal seam using the jet tool string includes:

[0038] The circular cross section formed by the rotary cutting and injection direction of the jet tool string is perpendicular to the top and bottom plates of the coal seam;

[0039] The coal seam is mined using the jet tool string.

[0040] In one possible implementation,

[0041] From the above description, it can be seen that the mining system and method provided by the present application, the system includes: a mechanical hole expansion and coal breaking module, an air lift reverse circulation lifting module, an abrasive jet hydraulic coal breaking module and a gas-water separation module; the mechanical hole expansion and coal breaking module includes: a drill rod rotating device, a drill rod and a hole expansion and groove drill bit; the drill rod rotating device, the drill rod and the hole expansion and groove drill bit are connected in sequence to perform rotary cutting, hole expansion and groove cutting operations on the coal seam in the coal mining borehole; the air lift reverse circulation lifting module includes an air compressor and a double-wall drill rod, so as to utilize the air compressor to transport the coal gas and water mixture through the inner tube channel of the double-wall drill rod to the gas-water separation module; the abrasive jet hydraulic coal breaking module includes: the drill rod rotating device, a fracturing vehicle, the drill rod and a jet tool string; the fracturing vehicle, the drill rod rotating device, the drill rod and the jet tool string are connected in sequence to mine the coal seam. The mining system proposed in the embodiment of the present application can first complete the mining of the coal seam without going down the well, effectively reducing the safety risks caused by coal and gas outburst, rock burst or water disaster during mining, and because no one goes down the well, only a few people are needed to operate the drilling rig on the ground to improve the working environment, and the present application also effectively saves labor costs. In addition, the ground supporting facilities in the embodiment of the present application are themselves movable, so the embodiment of the present application is very suitable for mining corner coal with uneven distribution or less coal resources. Moreover, the coal breaking process of the embodiment of the present application is firstly to mine coal in a small range by mechanical mining and then to mine coal in a large range by abrasive jet, so the embodiment of the present application can also be well applied to the mining of extra-thick coal seams and medium-hard to hard coal seams, and the above technical scheme can also be well adapted to three soft coal seams, "three-down" compressed coal, and coal and gas outburst coal seams. In addition, because the present application adopts water jet coal breaking, it can effectively avoid open flames, prevent combustion and explosion, and gas explosion on the one hand, and the flushing effect of underground water on the other hand is equivalent to completing an underground coal washing, killing two birds with one stone. In summary, the mining system of the embodiment of the present application has good adaptability, low cost, safety, greenness and high efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the technical solutions in the present application or related technologies, the drawings required for use in the embodiments or related technical descriptions are briefly introduced below. Obviously, the drawings described below are only embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0043] Figure 1 This is a schematic diagram of a mechanical hole-expanding and coal-breaking module according to an embodiment of the present application;

[0044] Figure 2This is a schematic diagram of the structure of a hole-reaming and slotting drill bit according to an embodiment of the present application;

[0045] Figure 3 A schematic longitudinal section diagram of a hole-reaming and slotting drill bit according to an embodiment of the present application;

[0046] Figure 4 This is a schematic diagram of a gas lift reverse circulation lifting module according to an embodiment of the present application;

[0047] Figure 5 This is a schematic diagram of an abrasive jet hydraulic coal breaking module according to an embodiment of the present application;

[0048] Figure 6 A schematic diagram of the mining method flow chart of an embodiment of the present application;

[0049] Figure 7 This is a schematic diagram of the distribution of the plastic zone around the groove space after the rotary cutting, hole expansion and groove cutting operation in an embodiment of the present application. DETAILED DESCRIPTION

[0050] In order to make the objectives, technical solutions and advantages of the present application more clearly understood, the present application is further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0051] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the embodiments of the present application should be the usual meanings understood by people with ordinary skills in the field to which the present application belongs. The "first", "second" and similar words used in the embodiments of the present application do not represent any order, quantity or importance, but are only used to distinguish different components. "Including" or "comprising" and similar words mean that the elements or objects appearing in front of the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0052] As mentioned in the background technology section, coal is an important energy source in China, and the development of coal resources has promoted the development of China's economy. However, due to the complex and changeable coal occurrence environment and mining conditions in China, my country's coal mining technology is more difficult than that of foreign coal mines. At the same time, traditional coal mine underground mining technology has great limitations and the safety of workers cannot be guaranteed. In addition, during the actual mining process of coal mines, it will be affected by coalbed methane, which makes the mining efficiency low, and even safety accidents often occur, seriously affecting the life safety of coal mining workers.

[0053] Coal is a non-renewable energy source and coexists with coalbed methane. With the continuous increase in mining intensity and demand, the issue of whether safe, efficient and high-recovery integrated mining of coal resources and coalbed methane resources can be achieved has gradually received attention. In terms of coal recovery rate, China's coal mines have serious residual corner coal and considerable reserves of corner coal, but the current corner coal mining technology is difficult and immature. The conventional wall mining and tunneling technology are limited in scope of application. The working face is short and has large changes. The mechanization of the fully mechanized mining and caving equipment used is difficult, and the installation, removal and relocation of working face equipment are frequent, which leads to complex mining processes, high coal mining costs and economic irrationality. In terms of disaster prevention and control, China's coal mines have serious gas disasters, complex coal seam geological conditions, and frequent coal mine gas accidents. The hydrological conditions of coal resources in western China are complex, and unreasonable working face layout and mining methods are prone to water inrush accidents, and mining safety issues are serious. Coal resources in eastern China have entered the deep mining stage, and shallow resources have been gradually exhausted. However, deep mining is difficult and costly. It not only faces complex geological conditions and unclear occurrence conditions, but also faces problems such as high ground stress, high ground temperature and high osmotic pressure. In terms of coalbed methane extraction, the coalbed methane pre-extraction technology in the early stage of conventional coal resource mining needs to be coordinated with the progress of coal mining in terms of extraction space and time. Under the rigid requirement of reducing gas content to meet the conditions of underground mining, it is also necessary to reduce the extraction time as much as possible to match the process requirements of extraction first and then construction, extraction first and then excavation, and extraction first and then mining, which leads to the increasing contradiction between the time and space succession of coalbed methane extraction and coal mine excavation.

[0054] Based on the above considerations, an embodiment of the present application proposes a mining system, which includes: a mechanical hole expansion and coal breaking module, an air lift reverse circulation lifting module, an abrasive jet hydraulic coal breaking module and a gas-water separation module; the mechanical hole expansion and coal breaking module includes: a drill rod rotating device, a drill rod and a hole expansion and groove cutting drill bit; the drill rod rotating device, the drill rod and the hole expansion and groove cutting drill bit are connected in sequence to perform rotary cutting, hole expansion and groove cutting operations on the coal seam in the coal mining borehole; the air lift reverse circulation lifting module includes an air compressor and a double-wall drill rod, so as to utilize the air compressor to transport the coal gas and water mixture through the inner tube channel of the double-wall drill rod to the gas-water separation module; the abrasive jet hydraulic coal breaking module includes: the drill rod rotating device, a fracturing vehicle, the drill rod and a jet tool string; the fracturing vehicle, the drill rod rotating device, the drill rod and the jet tool string are connected in sequence to mine the coal seam. The mining system proposed in the embodiment of the present application can first complete the mining of the coal seam without anyone going down the well, effectively reducing the safety risks caused by coal and gas outburst, rock burst or water disaster during mining, and because no one goes down the well, only a few people are needed to operate the drilling rig on the ground, which can effectively improve the working environment, and the present application also effectively saves labor costs. In addition, the ground supporting facilities in the embodiment of the present application are themselves movable, so the embodiment of the present application is very suitable for mining corner coal with uneven distribution or less coal resources. Moreover, the coal breaking process of the embodiment of the present application is firstly to mine coal in a small range by mechanical mining and then to mine coal in a large range by abrasive jet, so the embodiment of the present application can also be well applied to the mining of extra-thick coal seams and medium-hard to hard coal seams, and the above technical scheme can also be well adapted to three soft coal seams, "three-down" compressed coal, and coal and gas outburst coal seams. In addition, because the present application adopts water jet coal breaking, it can effectively avoid open flames, prevent combustion and explosion, and gas explosion on the one hand, and the flushing effect of underground water on the other hand is equivalent to completing an underground coal washing, killing two birds with one stone. In summary, the mining system of the embodiment of the present application has good adaptability, low cost, safety, greenness and high efficiency.

[0055] The technical solutions of the embodiments of the present application are described in detail below through specific examples.

[0056] First, the reference numerals are explained: drilling fluid truck 1, high-pressure pipeline 2, drill pipe rotating device 3, drill pipe 4, directional short section 5, hole expansion and grooving drill bit 6, gas-water separator 7, sedimentation tank 8, air compressor 9, gas faucet or gas box 10, double-wall drill pipe 11, gas-liquid mixer 12, single-wall drill pipe 13, roller drill bit 14, fracturing truck 15, mixing truck 16, abrasive tank truck 17, clean water tank 18, instrument truck 19, drilling fluid tank 20, fracturing tank truck 21, high-pressure hose 22, jet tool string 23, drill bit male buckle 24, diamond composite sheet 25, main blade wing 26, blade wing support rod 27, fixing spring 28, high-pressure water channel 29, central shaft 30, support 31, limit track 32.

[0057] In the embodiment of the present application, the mining system includes a mechanical hole expansion and coal breaking module, a gas lift reverse circulation lifting module, an abrasive jet hydraulic coal breaking module and a coal gas and water separation module. The above different modules work in the pre-built coal mining borehole at different times, so each module is described separately below.

[0058] refer to Figure 1 , is a schematic diagram of a mechanical hole expansion and coal breaking module according to an embodiment of the present application.

[0059] The mechanical hole reaming and coal breaking module includes: a drill rod rotating device 3, a drill rod 4 and a hole reaming and slotting drill bit 6; the drill rod rotating device 3, the drill rod 4 and the hole reaming and slotting drill bit 6 are connected in sequence. After the connection is completed, the hole reaming and slotting drill bit 6 lowered into the well is opened to perform rotary cutting, hole reaming and slotting operations on the coal seam in the coal mining borehole. The drill rod 4 is slowly lifted by the drill rod rotating device 3 at the wellhead, so that the hole reaming and slotting drill bit 6 is rotated and retracted to perform rotary cutting, hole reaming and slotting operations, thereby realizing mechanical primary crushing.

[0060] In some embodiments, the mechanical hole expansion and coal breaking module also includes: a drilling fluid truck 1 and a high-pressure pipeline 2; the drilling fluid truck 1 is set on the ground and connected to the coal mining borehole through the high-pressure pipeline 2; the drill rod rotation device 3 is set at the wellhead of the coal mining borehole.

[0061] Specifically, refer to Figure 1 In the embodiment of the present application, the mechanical reaming and coal breaking module includes a drilling fluid vehicle 1, a high-pressure pipeline 2, a drill rod rotating device 3, a drill rod 4, a directional short section 5, and a reaming and slotting drill bit 6. The ground coal mining drilling hole is drilled obliquely to the interface between the coal seam roof and the coal-rock layer, and a fiberglass casing is further laid parallel to the coal seam drilling hole; the drilling fluid vehicle 1 is set on the ground and connected to the coal mining drilling hole through the high-pressure pipeline 2; the drill rod rotating device 3 is set at the wellhead position of the coal mining drilling hole and connected to the drill rod 4, and the drill rod 4 runs through the entire coal mining drilling hole; the directional short section 5 is set at the drilling oblique part; the reaming and slotting drill bit 6 is installed at the bottom end of the drill rod. This module is mainly used for rotary cutting, reaming and slotting operations on the coal seam in the coal mining drilling hole.

[0062] refer to Figure 2 , which is a schematic diagram of the hole expansion and grooving drill bit structure of an embodiment of the present application.

[0063] refer to Figure 3 , which is a schematic longitudinal section diagram of a hole-reaming and grooving drill bit according to an embodiment of the present application.

[0064] like Figure 2 and Figure 3As shown in the figure, in this embodiment, the reaming and grooving drill bit 6 can be connected to the drill rod 4 through the drill bit male buckle 24, the blade wing 25 can be in a closed state during installation, the blade wing 25 is connected to the support 31 through the blade wing support rod 27, the central axis 30 is located at the center of the support 31, the high-pressure water channel 29 is connected to the central axis 30, 28 is a fixed spring, and 32 is a limiting track to limit the movement of the support 31.

[0065] refer to Figure 4 , is a schematic diagram of a gas lift reverse circulation lifting module according to an embodiment of the present application.

[0066] The gas lift reverse circulation lifting module includes an air compressor 9 and a double-wall drill pipe 11, so that the air compressor 9 can be used to transport the gas-water mixture to the gas-water separation module through the inner pipe channel of the double-wall drill pipe 11.

[0067] In some embodiments, the gas lift reverse circulation lifting module also includes: a single-wall drill pipe 13, a gas-liquid mixer 12 and a roller drill bit 14; the air compressor 9 is arranged on the ground and connected to the double-wall drill pipe 11 through a high-pressure pipeline 2; the gas-liquid mixer 12 is arranged at the lower end of the double-wall drill pipe 11 and is connected to the single-wall drill pipe 13; the single-wall drill pipe 13 is connected to the roller drill bit 14.

[0068] like Figure 4 As shown, in the embodiment of the present application, the gas lift reverse circulation lifting module includes an air compressor 9, a gas faucet or gas box 10, a double-wall drill pipe 11, a gas-liquid mixer 12, a single-wall drill pipe 13, and a roller drill bit 14. In some embodiments, the roller drill bit 14 is a special roller drill bit for reverse circulation.

[0069] Specifically, the air compressor 9 is set on the ground and connected to the air faucet or air box 10 through the high-pressure pipeline 2; the air faucet or air box 10 is set at the top of the double-wall drill pipe 11; the double-wall drill pipe 11 is set at the wellhead and extends to the vertical section of the drilling, and a gas-liquid mixer 12 is set at the end of the double-wall drill pipe 11; the double-wall drill pipe 11 is connected to the single-wall drill pipe 13 in the vertical section, the single-wall drill pipe 13 runs through the inclination section and the horizontal section, and the end of the double-wall drill pipe is connected to the roller drill bit 14.

[0070] Figure 4 A gas-water separation module is also shown.

[0071] In some embodiments, the gas-water separation module includes: a gas-water separator 7 and a sedimentation tank 8; the gas-water separator 7 is connected to the double-wall drill pipe 11; the gas-water separator 7 is connected to the sedimentation tank 8.

[0072] In some embodiments, a water baffle is provided in the sedimentation tank 8; a water pump is provided at the bottom of the sedimentation tank 8 to pump the water in the sedimentation tank 8 to the coal mining borehole, which can replenish the water between the borehole and the gas lift reverse circulation lifting module, thereby maintaining water recycling.

[0073] In this embodiment, if Figure 4 As shown, the gas-water separator 7 is connected to the double-wall drill pipe 11; the gas-water separator 7 is connected to the sedimentation tank 8. The gas and water lifted up by the double-wall drill pipe 11 enter the gas-water separator 7, thereby separating and purifying the coalbed methane and the coal and water, and the coal-water mixture formed after the initial separation enters the sedimentation tank 8. The sedimentation tank 8 is connected to the pipeline for conveying coal slurry, and a water inlet baffle is set in the tank to speed up the separation of coal and water. The bottom of the sedimentation tank 8 is set as a trapezoidal area for settling the coal particles extracted. A water pump is set at the bottom of the sedimentation tank 8 to evacuate the water to the drilling well through a pipeline, so as to supplement the water between the borehole and the gas lift reverse circulation equipment, so as to circulate water.

[0074] refer to Figure 5 , is a schematic diagram of an abrasive jet hydraulic coal breaking module according to an embodiment of the present application.

[0075] The abrasive jet hydraulic coal breaking module includes: the drill rod rotating device 3, the fracturing vehicle 15, the drill rod 4 and the jet tool string 23; the fracturing vehicle 15, the drill rod rotating device 3, the drill rod 4 and the jet tool string 23 are connected in sequence to mine the coal seam.

[0076] In some embodiments, the abrasive jet hydraulic coal breaking module also includes: a mixing vehicle 16, an abrasive tank vehicle 17 and a clean water tank 18; the abrasive tank vehicle 17 and the clean water tank 18 are respectively connected to the mixing vehicle 16; the mixing vehicle 16 is connected to the fracturing vehicle 15 to supply mixed abrasives; the fracturing vehicle 15 is connected to the drill pipe 4 through a high-pressure hose 22 to supply high-pressure abrasives.

[0077] like Figure 5 As shown, in the embodiment of the present application, the abrasive jet hydraulic coal breaking module includes a fracturing truck 15, a mixing truck 16, an abrasive tank truck 17, a clean water tank 18, an instrument truck 19, a drilling fluid tank 20, a fracturing tank truck 21, a high-pressure hose 22, and a jet tool string 23.

[0078] The fracturing truck 15, the mixing truck 16, the abrasive tank truck 17, the clean water tank 18, the instrument truck 19, the drilling fluid tank 20, and the fracturing tank truck 21 are arranged on the ground, one end of the drilling fluid tank 20 is connected to the gas-water separator 7, and the other end is connected to the fracturing tank truck 21; the abrasive tank truck 17 and the clean water tank 18 are respectively connected to the mixing truck 16; the instrument truck 19 and the mixing truck 16 are connected to each other to observe and adjust the pressure in real time; the mixing truck 16 is connected to the fracturing truck 15; the fracturing truck 15 is connected to the wellhead drill pipe 4 through one end of the high-pressure hose 22; the jet tool string 23 is arranged at the end of the drill pipe 4.

[0079] It can be seen from the above embodiments that the mining system described in the embodiments of the present application includes: a mechanical hole reaming and coal breaking module, an air lift reverse circulation lifting module, an abrasive jet hydraulic coal breaking module and a gas-water separation module; the mechanical hole reaming and coal breaking module includes: a drill rod rotating device, a drill rod and a hole reaming and groove cutting drill bit; the drill rod rotating device, the drill rod and the hole reaming and groove cutting drill bit are connected in sequence to perform rotary cutting, hole reaming and groove cutting operations on the coal seam in the coal mining borehole; the air lift reverse circulation lifting module includes an air compressor and a double-wall drill rod, so as to utilize the air compressor to transport the coal gas and water mixture through the inner tube channel of the double-wall drill rod to the gas-water separation module; the abrasive jet hydraulic coal breaking module includes: the drill rod rotating device, a fracturing vehicle, the drill rod and a jet tool string; the fracturing vehicle, the drill rod rotating device, the drill rod and the jet tool string are connected in sequence to mine the coal seam. The mining system proposed in the embodiment of the present application can first complete the mining of the coal seam without going down the well, effectively reducing the safety risks caused by coal and gas outburst, rock burst or water disaster during mining, and because no one goes down the well, only a few people are needed to operate the drilling rig on the ground to improve the working environment, and the present application also effectively saves labor costs. In addition, the ground supporting facilities in the embodiment of the present application are themselves movable, so the embodiment of the present application is very suitable for mining corner coal with uneven distribution or less coal resources. Moreover, the coal breaking process of the embodiment of the present application is firstly to mine coal in a small range by mechanical mining and then to mine coal in a large range by abrasive jet, so the embodiment of the present application can also be well applied to the mining of extra-thick coal seams and medium-hard to hard coal seams, and the above technical scheme can also be well adapted to three soft coal seams, "three-down" compressed coal, and coal and gas outburst coal seams. In addition, because the present application adopts water jet coal breaking, it can effectively avoid open flames, prevent combustion and explosion, and gas explosion on the one hand, and the flushing effect of underground water on the other hand is equivalent to completing an underground coal washing, killing two birds with one stone. In summary, the mining system of the embodiment of the present application has good adaptability, low cost, safety, greenness and high efficiency.

[0080] Based on the same inventive concept, corresponding to any of the above-mentioned embodiment methods, the present application also provides a mining method, which is applied to the above-mentioned mining system.

[0081] refer to Figure 6 , is a schematic diagram of the mining method flow of an embodiment of the present application, and the mining method flow of the embodiment of the present application specifically includes the following steps:

[0082] Step S601, using a mechanical hole-reaming and coal-breaking module to perform rotary cutting, hole-reaming and slotting operations on the coal seam in the pre-built coal mining borehole;

[0083] Step S602, using the gas lift reverse circulation lifting module to transport the gas-water mixture formed after the rotary cutting, reaming and grooving operation to the gas-water separation module;

[0084] Step S603, using the abrasive jet hydraulic coal breaking module to perform jet coal breaking operation on the coal seam;

[0085] Step S604, using the gas lift reverse circulation lifting module to transport the coal gas-water mixture formed after the jet coal breaking operation to the coal gas-water separation module;

[0086] Step S605: using the coal gas-water separation module to separate the coal gas-water mixture to obtain coal, coalbed methane and water.

[0087] Before performing step S601, it is necessary to pre-build the coal mining drilling hole and pre-arrange various equipment.

[0088] Specifically, the ground penetrating radar detection method is first used in combination with the data of the existing drilling holes to determine the buried depth, thickness, distribution range, and lithology of the top and bottom rock layers of the coal seam to be mined, and then the length of the mining face, the mining range, and the coal entry point are determined. Then, the coal mining borehole is constructed, and a coal slurry sedimentation tank 8 is constructed near the coal mining borehole.

[0089] Then, ground construction is carried out, and a drilling fluid truck 1, a gas-water separator 7, an air compressor 9, a fracturing truck 15, a mixing truck 16, an abrasive tank truck 17, a clean water tank 18, an instrument truck 19, a drilling fluid tank 20, and a fracturing tank truck 21 are arranged near the coal mining borehole.

[0090] Then, the L-shaped extraction channel is constructed. The coal mining borehole is drilled with a Ф311mm drill bit to drill into the bedrock, and a Ф245mm steel pipe is lowered for cementing. The cementing cement is returned to the ground to prevent the hole from collapsing. The Ф215.9mm drill bit is used for the second drilling, and the inclined drilling is carried out to the top of the coal seam. A Ф177.8mm steel pipe is lowered for cementing. The cementing cement is returned to the ground to prevent the hole from collapsing. The Ф152mm drill bit is used for the third drilling, and the hole is drilled to the final hole position above the bottom of the coal seam. A Ф89mm glass fiber reinforced plastic casing is lowered for cementing, forming an L-shaped construction section. After determining the length of the drill rod 4 according to the buried depth of the coal seam, the drill rod 4 equipped with the hole reaming and slotting drill bit 6 is lowered into the coal mining borehole, and the hole reaming and slotting drill bit 6 is located at the designated working surface position, and then the drill rod 4 is installed and connected with the drill rod rotating device 3, and finally the various pipelines are connected.

[0091] For step S601, when all the equipment is installed, the hole-reaming and slotting drill bit 6 is installed on the upper drill rod 4 through the drill bit male buckle 24. After the installation is completed, ensure that the blade 25 of the hole-reaming and slotting drill bit 6 is in a closed state; under the drive of the bottom hole motor, the guide drill bit drills to the target coal seam position, that is, the lower limit position of the hole to be expanded; turn on the out-of-hole drilling rig, start the drill rod 4 to rotate at a low speed, gradually increase the pump volume, and the high-pressure water flow enters the cavity through the high-pressure water channel 29, pushing the support 31 to move downward along the central axis 30. The support 31 pushes the blade support rod 27 to move downward synchronously, so that the blade 26 is slowly opened under the action of the high-pressure water flow along with the drill rod 4, and the drilling amount increases until the blade 26 is fully opened and forms a cross with the hole-reaming and slotting drill bit 6. The drill rod 4 and the hole-reaming and slotting drill bit 6 rotate synchronously, driving the hole-reaming and slotting drill bit 6 to cut the coal seam to achieve the purpose of hole expansion. It is recommended to withdraw the drill rod 0.5m per minute. The withdrawal speed can be dynamically adjusted according to the amount of coal returned from the wellhead. After the drill rod 4 is withdrawn for 5m (the range of the first section and the withdrawal distance can be adjusted according to the amount of coal and actual conditions), stop withdrawing, reduce the rotation speed, reduce the pump pressure gradually to the pump pressure of the closure blade 26, and withdraw the drill for a certain distance; as the pump pressure decreases, the reaming blade 26 is closed and retracted into the reaming and slotting drill bit 6 under the action of the fixed spring 28; the drilling rig outside the hole is turned off. At this time, the reaming and slotting task of the first section is completed.

[0092] refer to Figure 7 , which is a schematic diagram of the distribution of the plastic zone around the groove space after the rotary cutting, hole expansion and groove cutting operation in an embodiment of the present application.

[0093] After coal is mined, the pressure of the rock mass above the small cavitation space will be transferred to the surrounding coal mass, resulting in stress concentration. At the same time, the surrounding coal mass changes from the three-dimensional principal stress state of the original rock to bidirectional or even unidirectional stress, and the strength is reduced accordingly, causing varying degrees of damage to the surrounding coal mass, and the stress is sharply reduced, while the high concentrated stress is gradually transferred to the three-dimensional stress body deep in the coal mass. The advanced support pressure generated by the concentrated stress is used to assist in fracturing the coal at the front end of the mining area. At the same time, a small plastic loosening zone is generated around the small cavitation space. The small cavitation space formed by mechanical mining forms a three-dimensional cavity free surface for subsequent hydraulic mining and coal breaking, and causes varying degrees of damage to the surrounding coal mass, resulting in a small loosening zone, which provides convenience for subsequent hydraulic mining, saves energy, and improves efficiency.

[0094] With respect to step S602, in some embodiments, the use of an air lift reverse circulation lifting module to transport the coal-gas-water mixture formed after the jet coal breaking operation to the coal-gas-water separation module includes: using the air compressor 9 in the air lift reverse circulation lifting module to deliver high-pressure air to the annular gap between the inner and outer pipe walls of the double-wall drill pipe 11, delivering gas to the coal-gas-water mixture in the inner pipe of the double-wall drill pipe 11 through the gas-liquid mixer 12 in the air lift reverse circulation lifting module, and using reverse circulation to transport the coal-gas-water mixture to the coal-gas-water separation module in turn through the single-wall drill pipe 13 in the air lift reverse circulation lifting module and the inner pipe channel of the double-wall drill pipe 11 in the air lift reverse circulation lifting module.

[0095] In this embodiment, when the task of reaming and grooving in the first section is completed, the drill pipe 4 and the reaming and grooving drill bit 6 are withdrawn, and the single-wall drill pipe 13 and the double-wall drill pipe 11 with the reverse circulation special roller drill bit 14 at the end are lowered, and the gas-liquid mixer 12 is placed at the bottom of the double-wall drill pipe 11. After installation, the air compressor 9 is turned on, and the air is mixed into the gas-water mixture through the gas-liquid mixer 12 in the gas lift reverse circulation lifting module. The pressure difference between the inner pipe channel of the double-wall drill pipe 11 and the borehole is used to transport the gas-water mixture along the inner pipe channel to the gas-water separator 7 in the gas-water separation module, and the air compressor 9 is turned off after completion. At this time, the mechanical mining of the first section is completed.

[0096] With respect to step S603, in some embodiments, the use of the abrasive jet hydraulic coal breaking module to perform jet coal breaking operations on the coal seam includes: using the fracturing vehicle 15 in the abrasive jet hydraulic coal breaking module to pressurize the water-sand in the mixing vehicle 16 in the abrasive jet hydraulic coal breaking module; transporting the pressurized water-sand to the jet tool string 23 in the abrasive jet hydraulic coal breaking module through a high-pressure hose 22; and using the jet tool string 23 to perform abrasive jet rotary cutting on the coal seam and perform retreat-type coal breaking mining.

[0097] In some embodiments, the use of the jet tool string 23 to mine the coal seam includes: making the circular cross section formed by the rotary cutting injection direction of the jet tool string 23 perpendicular to the top and bottom plates of the coal seam; and mining the coal seam using the jet tool string 23. It should be noted that the injection direction of the jet tool string 23 may not be perpendicular to the top and bottom plates of the coal seam, but when it is perpendicular to the top and bottom plates of the coal seam, the efficiency is higher, so it is used as a preferred embodiment in the embodiments of the present application.

[0098] In this embodiment, after the mechanical mining of the first section is completed, the double-wall drill pipe 11 and the single-wall drill pipe 13 are taken out, and the drill pipe 4 and the jet tool string 23 are lowered to perform secondary coal breaking in the same section. The high-pressure sand-carrying water jet tool string 23 is installed at the end of the drill pipe 4, and the jetting direction of the jet tool string 23 is set vertically to the top and bottom plates of the coal seam. The abrasive and clean water in the abrasive tank car 17 and the clean water tank 18 are transported to the mixing car 16; the water sand in the mixing car 16 is pressurized by the fracturing car 15 and transported to the high-pressure sand-carrying water jet tool string 23 through the high-pressure hose 22, and is sprayed through the nozzle of the high-pressure sand-carrying water jet tool string 23 to form a high-pressure water jet. At the same time, the drill pipe rotating device 3 drives the drill pipe 4 to rotate so that the high-pressure water jet breaks the coal twice in the same section within the circumference, and then the jet tool string 23 is rotated while retreating at a uniform speed of 0.5m per minute until the jet tool string 23 mines the working face of the coal seam section, and finally the drill pipe 4 and the jet tool string 23 are taken out. The jet coal breaking operation can realize secondary hole expansion after mechanical coal breaking, making up for the fact that the extra-thick coal seam cannot be completely mined due to the influence of the maximum coal breaking radius of the mechanical hole expansion equipment. The jet technology is used to increase the coal cutting range to the top and bottom plates of the coal seam and secondary crush the broken coal body formed by mechanical coal breaking. It should be noted that the aforementioned uniform retreat speed of 0.5 meters per minute is only exemplary, and other retreat speeds can be adopted in other embodiments of the present application, which can be adjusted accordingly according to the actual amount of coal and other on-site conditions.

[0099] Further, with respect to step S604, in this embodiment, after the coal seam is mined using the jet tool string 23, the double-wall drill pipe 11 is lowered again, and the gas-water mixture is lifted to the gas-water separator 7 through the inner tube channel of the double-wall drill pipe 11 for reverse circulation. At this time, the coal seam of the working face of the section has been mined, that is, the mining process is completed. Then the double-wall drill pipe 11 is raised, and the reaming and slotting drill bit 6 and the drill pipe 4 are lowered to the position of the coal seam in the second section, and the small-scale mechanical coal breaking in the second section is carried out. The above steps are repeated to complete the mining of the coal seam in the second section, and then the third section, and so on, and the backward operation is carried out until the coal seam in the area is mined.

[0100] With respect to step S605, in this embodiment, during the mining process, the crushed coal powder and water are fully mixed, and the coalbed methane is located at the upper part thereof, and is transported to the gas-water separator 7 through the inner tube channel of the double-wall drill pipe 11. After the separation is completed, the mixture is transported to the sedimentation tank 8; the bottom of the sedimentation tank 8 is coal slag, and the upper part is filtered wastewater. Under the action of the water pump, the water in the sedimentation tank 8 is evacuated to the wellhead through the pipeline, and can be continuously recycled to realize the underground coal cutting operation. The aforementioned coalbed methane is low-concentration coalbed methane.

[0101] It can be seen from the above embodiments that the mining method described in the embodiments of the present application uses a mechanical hole-reaming and coal-breaking module to perform rotary cutting, hole-reaming and slotting operations on the coal seam in the pre-built coal mining borehole; uses a gas lift reverse circulation lifting module to transport the coal gas and water mixture formed after the rotary cutting, hole-reaming and slotting operations to the coal gas and water separation module; uses the abrasive jet hydraulic coal breaking module to perform jet coal breaking operations on the coal seam; uses a gas lift reverse circulation lifting module to transport the coal gas and water mixture formed after the jet coal breaking operations to the coal gas and water separation module; uses the coal gas and water separation module to separate the coal gas and water mixture to obtain coal, coalbed methane and water. The embodiments of the present application can realize unmanned underground mining, fundamentally ensuring the safety of mining, and this technology has strong adaptability to coal seams, and can be used for mining coal resources with complex geological structures, high mining difficulties and high risk factors such as corner coal, thereby increasing the coal production in the mine, reducing the amount of coal lost at the working face, thereby increasing the coal recovery rate and extending the mining life of the coal mine. The two coal-breaking modes of mechanical hole expansion and abrasive jet reduce the particle size of coal slag, expand the coal mining radius, increase the mining thickness, and reduce the scope of coal residue at the bottom of the well. Mechanical hole expansion provides a large-size coal-breaking space for abrasive jet, and the reasonable use of advanced support pressure and plastic ring improves the efficiency of abrasive jet coal-breaking. The two cooperate with each other to achieve better coal-breaking effect and stronger adaptability to coal seam thickness. On the one hand, water jet coal-breaking avoids open flames, prevents combustion and explosion, and gas explosions. On the other hand, the flushing effect of underground water is equivalent to completing an underground coal washing. As China's coal resources with better shallow coal storage conditions are gradually exhausted, the coal mining industry has gradually turned to deep coal resource mining. This embodiment can realize deep coal resource mining, expand the amount of coal exploitable resources, and realize the simultaneous mining of coal gas resources, forming a coordinated cooperation between coalbed methane mining and coal resource mining in time and space. In addition, the water in this application can be recycled, saving costs, reducing resource waste and environmental pollution.

[0102] It should be noted that the method of the embodiment of the present application can be performed by a single device, such as a computer or server. The method of this embodiment can also be applied to a distributed scenario and completed by multiple devices cooperating with each other. In the case of such a distributed scenario, one of the multiple devices can only perform one or more steps in the method of the embodiment of the present application, and the multiple devices will interact with each other to complete the described method.

[0103] It should be noted that the above describes some embodiments of the present application. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recorded in the claims can be performed in an order different from that in the above embodiments and still achieve the desired results. In addition, the processes depicted in the accompanying drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0104] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present application (including the claims) is limited to these examples. In line with the concept of the present application, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the embodiments of the present application as described above, which are not provided in detail for the sake of simplicity.

[0105] In addition, to simplify the description and discussion, and in order not to make the embodiments of the present application difficult to understand, the known power supply / ground connection with the integrated circuit (IC) chip and other components may or may not be shown in the provided drawings. In addition, the device can be shown in the form of a block diagram to avoid making the embodiments of the present application difficult to understand, and this also takes into account the fact that the details of the implementation of these block diagram devices are highly dependent on the platform to be implemented in the embodiments of the present application (that is, these details should be fully within the scope of understanding of those skilled in the art). In the case of elaborating specific details (e.g., circuits) to describe exemplary embodiments of the present application, it is obvious to those skilled in the art that the embodiments of the present application can be implemented without these specific details or when these specific details are changed. Therefore, these descriptions should be considered to be illustrative rather than restrictive.

[0106] Although the present application has been described in conjunction with specific embodiments of the present application, many replacements, modifications and variations of these embodiments will be apparent to those skilled in the art from the foregoing description. For example, other memory architectures (e.g., dynamic RAM (DRAM)) may use the embodiments discussed.

[0107] The embodiments of the present application are intended to cover all such substitutions, modifications and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the embodiments of the present application should be included in the scope of protection of the present application.

Claims

1. A mining method, characterized in that: Applied to a mining system, the mining system includes: a mechanical hole expansion and coal breaking module, a gas lift reverse circulation lifting module, an abrasive jet hydraulic coal breaking module and a coal gas and water separation module; The mechanical hole-reaming and coal-breaking module comprises: a drill rod rotating device, a drill rod and a hole-reaming and slotting drill bit; the drill rod rotating device, the drill rod and the hole-reaming and slotting drill bit are connected in sequence to perform rotary cutting, hole-reaming and slotting operations on the coal seam in the coal mining borehole; The gas lift reverse circulation lifting module includes an air compressor and a double-wall drill pipe, so that the air compressor is used to transport the gas-water mixture to the gas-water separation module through the inner pipe channel of the double-wall drill pipe; The abrasive jet hydraulic coal breaking module comprises: the drill pipe rotating device, the fracturing vehicle, the drill pipe and the jet tool string; the fracturing vehicle, the drill pipe rotating device, the drill pipe and the jet tool string are connected in sequence to mine the coal seam; The method comprises: Use the mechanical hole-reaming and coal-breaking module to perform rotary cutting, hole-reaming and slotting operations on the coal seams in the pre-built coal mining boreholes; The gas-water mixture formed after rotary cutting, reaming and slotting operations is transported to the gas-water separation module by using the gas lift reverse circulation lifting module; Using the abrasive jet hydraulic coal breaking module to perform jet coal breaking operation on the coal seam; The gas-water mixture formed after the jet coal breaking operation is transported to the gas-water separation module by using the gas lift reverse circulation lifting module; The coal gas and water separation module is used to separate the coal gas and water mixture to obtain coal, coalbed methane and water.

2. The mining method according to claim 1, characterized in that: The method of using the gas lift reverse circulation lifting module to transport the coal gas-water mixture formed after the jet coal breaking operation to the coal gas-water separation module includes: The air compressor in the gas lift reverse circulation lifting module is used to deliver high-pressure air to the annular gap between the inner and outer pipe walls of the double-wall drill pipe, and the gas is delivered to the gas-water mixture in the inner pipe channel of the double-wall drill pipe through the gas-liquid mixer in the gas lift reverse circulation lifting module. The gas-water mixture is transported to the gas-water separation module in turn through the single-wall drill pipe in the gas lift reverse circulation lifting module and the inner pipe channel of the double-wall drill pipe in the gas lift reverse circulation lifting module by reverse circulation.

3. The mining method according to claim 1, characterized in that: The method of using the abrasive jet hydraulic coal breaking module to perform jet coal breaking operation on the coal seam includes: Using the fracturing vehicle in the abrasive jet hydraulic coal breaking module to pressurize the water-sand in the mixing vehicle in the abrasive jet hydraulic coal breaking module; The pressurized water sand is transported to the jet tool string in the abrasive jet hydraulic coal breaking module through a high-pressure hose; The jet tool string is used to perform abrasive jet rotary cutting on the coal seam and withdraw coal breaking mining.

4. The method according to claim 1, characterized in that: The method of mining the coal seam by using the jet tool string comprises: The circular cross section formed by the rotary cutting and injection direction of the jet tool string is perpendicular to the top and bottom plates of the coal seam; The coal seam is mined using the jet tool string.

Images