CN111485935A - Equipment and method for annular cave making and permeability increasing by using supersonic rotary air knife in underground coal mine - Google Patents
Equipment and method for annular cave making and permeability increasing by using supersonic rotary air knife in underground coal mine Download PDFInfo
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- 239000003245 coal Substances 0.000 title claims abstract description 72
- 238000000034 method Methods 0.000 title claims abstract description 30
- 230000035699 permeability Effects 0.000 title abstract description 9
- 230000008569 process Effects 0.000 claims abstract description 15
- 230000008595 infiltration Effects 0.000 claims abstract description 6
- 238000001764 infiltration Methods 0.000 claims abstract description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 85
- 238000005553 drilling Methods 0.000 claims description 50
- 238000003860 storage Methods 0.000 claims description 21
- 238000001914 filtration Methods 0.000 claims description 11
- 230000001105 regulatory effect Effects 0.000 claims description 8
- 238000005520 cutting process Methods 0.000 claims description 7
- 238000001816 cooling Methods 0.000 claims description 3
- 238000000605 extraction Methods 0.000 abstract description 16
- 238000010276 construction Methods 0.000 abstract description 5
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- 238000009412 basement excavation Methods 0.000 description 1
- 235000019994 cava Nutrition 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21F—SAFETY DEVICES, TRANSPORT, FILLING-UP, RESCUE, VENTILATION, OR DRAINING IN OR OF MINES OR TUNNELS
- E21F7/00—Methods or devices for drawing- off gases with or without subsequent use of the gas for any purpose
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
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Abstract
The invention relates to the technical field related to coal mine gas enhanced extraction, in particular to annular cave-making and permeability-increasing equipment and method for an ultrasonic rotary air knife under a coal mine. The annular cavitation and infiltration increasing method of the supersonic speed rotating air knife disclosed by the invention utilizes the supersonic speed gas with multiple Mach numbers formed by accelerating medium pressure (5-20MPa) gas through the Laval nozzle, forms the annular air knife in the process of rotating and withdrawing the drill bit, completes the cavitation and infiltration increasing process of 'withdrawing-advancing-withdrawing' according to different preset pressures, effectively discharges cavitation coal slag and completes the cavitation and infiltration increasing, and simultaneously, the invention also provides a calculation method of the preset pressure. The method has safe construction and simple operation, avoids the problems of hole blocking and gas desorption inhibition easily caused by hydraulic cave building, and can effectively carry out cave building, permeability increasing and enhanced extraction on the soft coal seam.
Description
Technical Field
The invention relates to the technical field of coal mine gas enhanced extraction, is mainly suitable for low-permeability broken soft coal seams which are difficult to extract, and particularly relates to annular cave-making and permeability-increasing equipment and method for an ultrasonic rotary air knife in a coal mine.
Background
Gas disasters are the most harmful of coal mine disasters, and accidents such as coal and gas outburst and gas explosion have seriously threatened the safety production of coal mines in China. The gas extraction is a main technical means for treating coal mine gas disasters, is influenced by coal mine excavation deployment and connection, and particularly for low-permeability broken soft coal seams which are difficult to extract, how to extract gas in the coal seams within a limited time is the biggest problem which puzzles coal mine gas disaster treatment work. The hydraulic hole making technology utilizes a connecting channel of a drill rod and a drill bit to convey high-pressure water (with the pressure of 20-100MPa) in the drilling process or the drilling and retreating process of a drilling machine, so that coal bodies around drilled holes are impacted to enlarge the hole diameter of the drilled holes, and holes in a coal seam are artificially made, so that the effective flowing area of gas in the extraction process is enlarged, the stress of the coal seam is released in the deformation process of the drilled holes, and the permeability of the coal body is improved. The method for improving the coal seam gas extraction efficiency achieves certain effect and is applied to a plurality of mining areas.
However, the adsorption potential well of water with strong polarity on the coal surface is far larger than gas, so that water molecule clusters are easily formed in micro-cracks and large pores of the coal body to block a gas migration channel, particularly a migration channel for outward diffusion of desorbed gas, and a large amount of liquid water can be reserved in a lower hole which is drilled downwards or caved, so that the effective extraction area of the drilled hole is reduced, and the water is difficult to extract by extraction negative pressure of an extraction system. Therefore, although hydraulic cave building can promote the development and development of partial fractures at the initial stage so as to improve the permeability coefficient of the coal body to a certain extent, the hydraulic cave building has an inhibiting effect on the desorption of gas molecules and is not beneficial to quickly reducing the adsorbed gas content in the coal bed in the long term, and the search of a new waterless cave building method has very important significance on the permeability increment and the enhanced extraction of the coal bed.
For example, patent document (Z L201510006074.0) proposes an apparatus and a method for breaking coal by high-pressure abrasive gas jet flow, releasing pressure and increasing permeability, wherein the high-pressure abrasive gas jet flow formed by mixing high-pressure air and abrasive is conveyed to a nozzle of a drill bit to erode coal bodies.
The information disclosed in this background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.
Disclosure of Invention
The invention provides equipment and a method for annular cave-making and permeability-increasing by using a supersonic gas rotary air knife under a coal mine, aiming at the problems in the existing coal seam cave-making and permeability-increasing reinforced extraction technology. The device is simple, is convenient to operate, does not generate the phenomenon of water lock hole blocking, and can effectively perform reaming, permeability increasing and enhanced extraction on the coal bed.
In order to achieve the purpose, the invention adopts the following technical scheme:
in a first aspect, the present invention provides an annular cave-making and permeability-increasing device using a coal mine underground supersonic rotary air knife, comprising: the device comprises a drilling machine, an air guide and water guide double-channel drill rod, a supersonic gas jet drill bit, a compressed air filtering device, a high-pressure gas compressor, a high-pressure gas storage tank and a gas pressure adjusting device;
the inlet of the high-pressure gas compressor is connected with the compressed air filtering device;
the high-pressure gas compressor is connected with an inlet of the high-pressure gas storage tank;
the outlet of the high-pressure gas storage tank is connected with the inlet of the gas pressure regulating device;
the outlet of the gas pressure adjusting device is connected with the inlet of a gas guide and water guide double-channel drill rod on the drilling machine;
the gas guide and water guide double-channel drill rod is connected with the supersonic gas jet drill bit.
As a further aspect, the supersonic gas jet drill bit comprises: the drill bit comprises a drill bit body, a PDC drill bit cutting tool, a water guide nozzle, a supersonic gas Laval nozzle, a water guide passage, a gas guide pipeline interface and a drill bit interface;
the front end of the drill bit body is provided with a PDC drill bit cutting tool and a water guide nozzle;
the side surface of the drill bit body is provided with a supersonic gas Laval nozzle;
a water guide passage and an air guide pipe are arranged in the drill bit body, the water guide nozzle is communicated with the water guide passage, and the supersonic gas laval nozzle is communicated with the air guide pipe;
and the tail end of the drill bit body is provided with an air guide pipeline interface and a drill bit interface.
As a further technical scheme, the number of the water guide nozzles and the number of the supersonic gas Laval nozzles are 2.
As a further technical solution, the air-guiding and water-guiding dual-channel drill rod comprises: the drill pipe comprises a drill pipe body, a drill pipe joint, an air guide pipeline interface, a fixed check ring and a water guide passage;
a water guide passage is arranged in the drill rod body along the length direction of the drill rod body;
the inside of the water guide passage is provided with a gas guide pipeline along the length direction;
the air guide pipeline and the water guide passage are fixed through a fixed check ring;
one end of the drill rod body is provided with a drill rod joint, and the other end of the drill rod body is provided with a drill rod interface;
when the supersonic gas jet drill bit is connected with the air guide and water guide dual-channel drill rod, the drill rod joint of the drill rod body can be connected with the drill bit interface of the drill bit body, the water guide channel of the drill rod body can be connected with the water guide channel of the drill bit body, and meanwhile, the air guide channel of the drill rod body can be connected with the air guide channel of the drill bit body.
As a further technical scheme, a plurality of sections of the gas guide and water guide double-channel drill rods are connected in sequence and then connected with the supersonic gas jet drill bit.
As a further technical solution, the method further comprises: a high-pressure rubber hose; the high-pressure gas compressor passes through the high-pressure rubber tube with the entry of high-pressure gas holder links to each other, the export of high-pressure gas holder passes through the high-pressure rubber tube and links to each other with gas pressure adjusting device's entry, gas pressure adjusting device's export passes through the high-pressure rubber tube and links to each other with the air guide water guide double-channel drilling rod entry on the rig.
In a second aspect, the invention also provides a method for carrying out annular cave-making and permeability-increasing equipment according to the coal mine underground supersonic rotary air knife, which comprises the following steps:
s1, drilling by adopting a drilling machine, an air-guide water-guide double-channel drilling rod and a supersonic gas jet drill bit, connecting the air-guide water-guide double-channel drilling rod with a down-hole water pipe in the drilling process, drilling by adopting a water cooling mode, and stopping drilling after the drilling reaches a preset position;
s2, sequentially connecting the underground compressed air pipeline, the compressed air filtering device, the high-pressure gas compressor, the high-pressure gas storage tank, the gas pressure adjusting device and the air guide and water guide double-channel drill rod, starting the high-pressure gas compressor, and increasing the pressure of the high-pressure gas storage tank to 20 MPa;
s3, gradually increasing the gas pressure in the supersonic gas jet drill bit to a pressure level I by using a gas pressure adjusting device, accelerating high-pressure gas by using a supersonic gas Laval nozzle on the drill bit to form a supersonic gas knife, starting first-time hole making, rotating and retreating by using a drilling machine to form a supersonic annular gas knife to crush the coal body until the drill bit retreats to a preset hole making distance;
s4, gradually increasing the gas pressure to a pressure level II, rotating and drilling by using a drilling machine, further enlarging the hole making size, and avoiding the blockage of a drill hole caused by excessive coal body crushed by hole making at one time until the drill bit advances to the initial hole making position in the step S3;
s5, gradually increasing the gas pressure to a preset maximum pressure level III, and rotating and retreating the drill by using a drilling machine until the drill retreats to a preset position in the step S3;
s6, closing the gas inlet by using a gas pressure adjusting device, rotating and retreating the drill by using a drill until reaching the preset position for the second cave-making, and repeating the steps S3 to S5 to finish the second cave-making and seepage-increasing;
and S7, repeating the step S6 until the subsection cave making and seepage increasing of the preset times are finished.
As a further technical solution, the predetermined pressure level III satisfies the following formula:
in which a is a parameter associated with a predetermined pressure level III, i.e. P
P*For gas pressure in stagnation, H is the desired cavitation radius, b0Is the nozzle outlet cross-sectional area, T is the gas thermodynamic temperature, StRepresenting the throat area of the nozzle, rho is the air density, and v is the Poisson's ratio of the cave-making coal body.
As a further technical scheme, the pressure grade I is 1/2 of pressure grade III; the pressure level II is 3/4 of pressure level III.
By adopting the technical scheme, the invention has the following beneficial effects:
compared with the prior art, the technology provided by the invention introduces the concepts of Laval accelerating nozzles and supersonic gas propulsion of rocket engines in the field of aviation into the fields of coal seam cave-making and permeation enhancement and gas intensified extraction, utilizes the multi-Mach-number supersonic gas formed by accelerating medium-pressure (5-20MPa) gas through the Laval nozzles to form an annular air knife in the drill bit withdrawal process, and cuts off coal bodies around drilled holes to form pressure relief caves with larger diameters, so that elastic potential and gas expansion energy in the coal bodies are released under the action of ground stress, and the gas extraction is safely and efficiently intensified. Meanwhile, because the used gas pressure is moderate, the technology provided by the invention can not cause large stratum stress disturbance, damage the coal seam top and bottom plates or induce the construction process to be prominent, can ensure the technical safety and the construction safety, and has great application value.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.
FIG. 1 is a schematic view of an annular cavitation and infiltration enhancing apparatus according to the present invention;
FIG. 2 is a cross-sectional view of a supersonic gas jet drill bit according to the present invention;
FIG. 3 is a plane view of the air-guiding and water-guiding dual-channel drill rod in the present invention;
FIG. 4 is a schematic diagram of the process of the present invention in which a Laval nozzle accelerates a gas to supersonic velocity.
FIG. 5 is a schematic diagram of the effect of supersonic rotary air knife on ring-shaped staged cavitation and permeation enhancement.
In fig. 1: the device comprises a drilling machine 1, a coal mine underground roadway 2, a coal mine underground water pipeline 3, a cave-making target coal seam 4, an air guide and water guide double-channel drill rod 5, a supersonic gas jet drill 6, a coal mine underground compressed air pipeline 7, a compressed air filtering device 8, a high-pressure rubber pipe 9, a high-pressure gas compressor 10, a high-pressure gas storage tank 11, a high-pressure gas storage tank air inlet 111, a high-pressure gas storage tank air outlet 112, a high-pressure gas storage tank blow-off and pressure relief valve 113, a pressure gauge 114, a gas pressure adjusting device 12, a high-pressure ball valve 121 and a gas pressure adjusting valve 122.
In fig. 2: 61 is a PDC drill bit cutting tool, 62 is a water guide nozzle, 63 is a supersonic gas Laval nozzle, 64 is a water guide channel, 65 is a gas guide channel, 66 is a gas guide channel interface, and 67 is a drill bit interface.
In fig. 3: 51 is a drill rod joint, 52 is an air guide pipeline, 53 is an air guide pipeline interface, 54 is a fixed retainer ring, and 55 is a water guide channel; 56 is a water guide high-pressure rubber pipe; 57 is an air guide high pressure rubber pipe.
Detailed Description
The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
The following detailed description of embodiments of the invention refers to the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, not limitation.
Example one
Referring to fig. 1 to 5, the present invention provides a coal mine downhole supersonic rotary air knife annular cave-making and permeability-increasing device, which comprises: the device comprises a drilling machine 1, an air guide and water guide double-channel drill rod 5, a supersonic gas jet drill 6, a compressed air filtering device 8, a high-pressure gas compressor 10, a high-pressure gas storage tank 11 and a gas pressure adjusting device 12;
the inlet of the high-pressure gas compressor 10 is connected with the compressed air filtering device 8;
the high-pressure gas compressor 10 is connected with an inlet of the high-pressure gas storage tank 11;
the outlet of the high-pressure gas storage tank 11 is connected with the inlet of the gas pressure regulating device 12;
the outlet of the gas pressure adjusting device 12 is connected with the inlet of a gas guide and water guide double-channel drill rod 5 on the drilling machine, and the outlet of the gas pressure adjusting device is provided with a high-pressure ball valve 121 and a gas pressure adjusting valve 122 which are connected in series;
the gas guide and water guide double-channel drill rod 5 is connected with the supersonic gas jet drill 6.
As a further technical solution, the supersonic gas jet drill 6 comprises: the drill bit comprises a drill bit body, a PDC drill bit cutting tool 61, a water guide nozzle 62, a supersonic gas Laval nozzle 63, a water guide passage, a gas guide pipeline interface 66 and a drill bit interface 67;
the front end of the drill bit body is provided with a PDC drill bit cutting tool 61 and a water guide nozzle 62;
the side surface of the drill bit body is provided with a supersonic gas Laval nozzle;
a water guide passage and an air guide pipe are arranged in the drill bit body, the water guide nozzle is communicated with the water guide passage, and the supersonic gas laval nozzle is communicated with the air guide pipe;
the tail end of the drill bit body is provided with an air guide pipeline interface 66 and a drill bit interface 67.
As a further technical solution, the number of the water guide nozzles and the number of the supersonic gas laval nozzles 63 are 2.
As a further technical solution, the air-guiding and water-guiding dual-channel drill rod 5 comprises: the gas guide and water guide dual-channel drill rod 55 is connected with the coal mine underground water pipeline 3 through a water guide high-pressure rubber pipe 56 and is connected with an outlet of the gas pressure regulating device 12 through a gas guide high-pressure rubber pipe 57;
a water guide passage 55 is arranged in the drill rod body along the length direction of the drill rod body;
the water guide passage 55 is provided with a gas guide pipe 52 along the longitudinal direction thereof;
the air guide pipeline 52 and the water guide passage 55 are fixed through a fixing retainer ring 54;
one end of the drill rod body is provided with a drill rod joint 51, and the other end of the drill rod body is provided with a drill rod interface;
when the supersonic gas jet drill bit 6 is connected with the air guide and water guide double-channel drill rod 5, the drill rod joint 51 of the drill rod body can be connected with the drill bit interface 67 of the drill bit body, the water guide channel of the drill rod body can be connected with the water guide channel of the drill bit body, and meanwhile, the air guide channel of the drill rod body can be connected with the air guide channel of the drill bit body.
As a further technical scheme, a plurality of sections of the gas guide and water guide double-channel drill rods 5 are connected in sequence and then are connected with the supersonic gas jet drill 6.
As a further technical solution, the method further comprises: a high-pressure rubber pipe 9; the high-pressure gas compressor 10 pass through high-pressure rubber tube 9 with the entry of high-pressure gas holder links to each other, the export of high-pressure gas holder passes through high-pressure rubber tube 9 and links to each other with gas pressure adjusting device's entry, gas pressure adjusting device's export passes through high-pressure rubber tube 9 and links to each other with 5 entrys of the air guide water guide double-channel drilling rod on the rig.
Example two
The embodiment provides a method for annular hole making and permeability increasing by using an ultrasonic rotary air knife in a coal mine.
1) As shown in fig. 1, firstly, a drilling machine 1 is conveyed to a coal mine underground roadway 2 of a construction site, a coal mine underground water pipeline 3 is connected with the drilling machine 1, conventional water-cooling drilling construction is carried out on a hole-making target coal seam 4, but the drilling machine adopts an air-guiding and water-guiding double-channel drilling rod 5 and a supersonic gas jet drill bit 6, in the process, as shown in fig. 2, the air-guiding and water-guiding double-channel drilling rod 5 is connected with the coal mine underground water pipeline 3 through a water-guiding high-pressure rubber pipe 56, an air-guiding joint 55 is plugged by a screw cap, pressure water in the coal mine underground water pipeline 3 flows to the supersonic gas jet drill bit 6 through a water-guiding channel 55 in the air-guiding and water-guiding double-channel drilling rod 5, as shown in fig. 3, and is sprayed out through a water-guiding nozzle.
2) When the drilling machine drills, the underground compressed air pipeline 7 is connected with an inlet of a compressed air filtering device 8, an outlet of the compressed air filtering device 8 is connected with an inlet of a high-pressure gas compressor 10 by a high-pressure rubber pipe 9, an outlet of the high-pressure gas compressor 10 is connected with an air inlet 111 of a high-pressure gas storage tank, an air outlet 112 of the high-pressure gas storage tank is connected with a gas pressure adjusting device 12, a high-pressure ball valve 121 and a gas pressure adjusting valve 122 are closed, the high-pressure gas compressor 10 is started to inflate the high-pressure gas storage tank until the pressure of a pressure gauge 114 rises to 20MPa (the specific form of the high-pressure gas storage tank is.
3) Step 1, removing a water guide high-pressure rubber tube 56 connecting the underground water pipeline 3 and the air guide and water guide double-channel drill rod 5 after the completion of the step 1, connecting the outlet of the gas pressure regulating device with an air guide tube 55 of the air guide and water guide double-channel drill rod 5 by using an air guide high-pressure rubber tube 57, conveying high-pressure gas to a supersonic gas Laval nozzle 63 through an air guide tube 55 in the air guide and water guide double-channel drill rod 5 and an air guide tube interface 66 in a supersonic gas jet drill 6, regulating the gas pressure to a preset pressure grade I by using a gas pressure regulating valve 122, as shown in figure 4, accelerating the high-pressure gas by using the supersonic gas Laval nozzle 63 on the drill bit to 2-5 Mach numbers, forming huge impact force in a target distance range, namely a supersonic air knife, starting first hole making, and rotating and slowly withdrawing the drill by using the drilling machine 1, and forming a supersonic annular air knife during the rotation process, and crushing the coal body until the drill bit 6 retreats to a preset hole forming distance which is equal to a preset hole forming length.
Predetermined pressure level I is 1/2 of predetermined pressure level III (p), which is calculated by equation 1:
wherein a is a parameter associated with a predetermined pressure level III, P
P*For gas pressure in stagnation, H is the desired cavitation radius, b0Is the nozzle outlet cross-sectional area, T is the gas thermodynamic temperature, StRepresenting the throat area of the nozzle, rho is the air density, and v is the Poisson's ratio of the cave-making coal body.
The poisson ratio of the cave-making coal body can be measured through laboratory experiments.
4) Adjusting the gas pressure to a preset pressure level II by using a gas pressure adjusting valve 122, and performing rotary and slow drilling by using the drilling machine 1 to further enlarge the hole making size, and simultaneously avoiding the phenomenon that the drill hole is blocked due to excessive coal body crushed by hole making for one time until the drill bit 6 advances to the initial hole making position in the step 3, wherein the preset pressure level II is 3/4 of a preset pressure level III (P);
5) adjusting the gas pressure to a preset pressure grade III by using a gas pressure adjusting valve 122, rotating and retreating the drill by using the drill 1 until the drill bit 6 retreats to a preset position in the step 3, completing the current cave-making process, estimating the coal output at the drill hole in the cave-making process, comparing the actual coal output with the expected coal output, and evaluating the effect of the current cave-making, wherein the expected coal output can be calculated by an expected cave-making radius H and a preset cave-making length;
6) closing the high-pressure ball valve 121 and the gas pressure regulating valve 122, rotating and retreating the drill by using the drill 1 to a preset position for the second cave-making, and repeating the steps 3-5 to finish the second cave-making and infiltration increasing;
7) and (5) repeating the step (6) until the subsection cave-making and seepage-increasing for the preset times is finished, withdrawing the drill by using the drilling machine 1, finishing the whole process of drilling, cave-making and seepage-increasing for the time as shown in figure 5, connecting the drill hole with an extraction system, and performing extraction operation.
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.
Claims (9)
1. The utility model provides a colliery is supersound speed of a coal mine rotates air knife and carries out annular cave making and increase infiltration equipment which characterized in that includes: the device comprises a drilling machine, an air guide and water guide double-channel drill rod, a supersonic gas jet drill bit, a compressed air filtering device, a high-pressure gas compressor, a high-pressure gas storage tank and a gas pressure adjusting device;
the inlet of the high-pressure gas compressor is connected with the compressed air filtering device;
the outlet of the high-pressure gas compressor is connected with the inlet of the high-pressure gas storage tank;
the outlet of the high-pressure gas storage tank is connected with the inlet of the gas pressure regulating device;
the outlet of the gas pressure adjusting device is connected with the inlet of a gas guide and water guide double-channel drill rod on the drilling machine;
the gas guide and water guide double-channel drill rod is connected with the supersonic gas jet drill bit.
2. The coal mine downhole supersonic rotary air knife annular cave-making and permeability-increasing equipment as claimed in claim 1, wherein the supersonic gas jet drill comprises: the drill bit comprises a drill bit body, a PDC drill bit cutting tool, a water guide nozzle, a supersonic gas Laval nozzle, a water guide passage, a gas guide pipeline interface and a drill bit interface;
the front end of the drill bit body is provided with a PDC drill bit cutting tool and a water guide nozzle;
the side surface of the drill bit body is provided with a supersonic gas Laval nozzle;
a water guide passage and an air guide pipe are arranged in the drill bit body, the water guide nozzle is communicated with the water guide passage, and the supersonic gas laval nozzle is communicated with the air guide pipe;
and the tail end of the drill bit body is provided with an air guide pipeline interface and a drill bit interface.
3. The annular cave-making and permeability-increasing equipment adopting the coal mine underground supersonic rotating air knife as claimed in claim 1, wherein the number of the water guide nozzles and the supersonic gas laval nozzles is 2.
4. The coal mine underground ultrasonic rotary air knife annular cave-making and seepage-increasing equipment as claimed in claim 1, wherein the air-guide water-guide dual-channel drill rod comprises: the drill pipe comprises a drill pipe body, a drill pipe joint, an air guide pipeline interface, a fixed check ring and a water guide passage;
a water guide passage is arranged in the drill rod body along the length direction of the drill rod body;
the inside of the water guide passage is provided with a gas guide pipeline along the length direction;
the air guide pipeline and the water guide passage are fixed through a fixed check ring;
one end of the drill rod body is provided with a drill rod joint, and the other end of the drill rod body is provided with a drill rod interface;
when the supersonic gas jet drill bit is connected with the air guide and water guide dual-channel drill rod, the drill rod joint of the drill rod body can be connected with the drill bit interface of the drill bit body, the water guide channel of the drill rod body can be connected with the water guide channel of the drill bit body, and meanwhile, the air guide channel of the drill rod body can be connected with the air guide channel of the drill bit body.
5. The underground coal mine ultrasonic rotary air knife annular cave-making and permeability-increasing equipment according to claim 1, characterized in that a plurality of sections of the air-guide water-guide dual-channel drill rods are connected in sequence and then are connected with the ultrasonic gas jet drill bit.
6. The coal mine underground ultrasonic rotary air knife annular cave-making and permeability-increasing equipment as claimed in claim 1, further comprising: a high-pressure rubber hose;
the high-pressure gas compressor passes through the high-pressure rubber tube with the entry of high-pressure gas holder links to each other, the export of high-pressure gas holder passes through the high-pressure rubber tube and links to each other with gas pressure adjusting device's entry, gas pressure adjusting device's export passes through the high-pressure rubber tube and links to each other with the air guide water guide double-channel drilling rod entry on the rig.
7. The method for carrying out annular cave-making and permeability-increasing equipment by using the coal mine underground supersound rotating air knife according to any one of claims 1 to 6, is characterized by comprising the following steps:
s1, drilling by adopting a drilling machine, an air-guide water-guide double-channel drilling rod and a supersonic gas jet drill bit, connecting the air-guide water-guide double-channel drilling rod with a down-hole water pipe in the drilling process, drilling by adopting a water cooling mode, and stopping drilling after the drilling reaches a preset position;
s2, sequentially connecting the underground compressed air pipeline, the compressed air filtering device, the high-pressure gas compressor, the high-pressure gas storage tank, the gas pressure adjusting device and the air guide and water guide double-channel drill rod, starting the high-pressure gas compressor, and increasing the pressure of the high-pressure gas storage tank to 20 MPa;
s3, gradually increasing the gas pressure in the supersonic gas jet drill bit to a pressure level I by using a gas pressure adjusting device, accelerating high-pressure gas by using a supersonic gas Laval nozzle on the drill bit to form a supersonic gas knife, starting first-time hole making, rotating and retreating by using a drilling machine to form a supersonic annular gas knife to crush the coal body until the drill bit retreats to a preset hole making distance;
s4, gradually increasing the gas pressure to a pressure level II, rotating and drilling by using a drilling machine, further enlarging the hole making size, and avoiding the blockage of a drill hole caused by excessive coal body crushed by hole making at one time until the drill bit advances to the initial hole making position in the step S3;
s5, gradually increasing the gas pressure to a preset maximum pressure level III, and rotating and retreating the drill by using a drilling machine until the drill retreats to a preset position in the step S3;
s6, closing the gas inlet by using a gas pressure adjusting device, rotating and retreating the drill by using a drill until reaching the preset position for the second cave-making, and repeating the steps S3 to S5 to finish the second cave-making and seepage-increasing;
and S7, repeating the step S6 until the subsection cave making and seepage increasing of the preset times are finished.
8. The apparatus of claim 7, wherein the predetermined pressure level III satisfies the following equation:
in which a is a parameter associated with a predetermined pressure level III, i.e. P
P*For gas pressure in stagnation, H is the desired cavitation radius, b0Is the nozzle outlet cross-sectional area, T is the gas thermodynamic temperature, StRepresenting the throat area of the nozzle, rho is the air density, and v is the Poisson's ratio of the cave-making coal body.
9. The coal mine underground supersound rotary air knife annular cave-making and permeability-increasing equipment according to claim 8,
the pressure grade I is 1/2 of pressure grade III;
the pressure level II is 3/4 of pressure level III.
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| CN111980706A (en) * | 2020-09-02 | 2020-11-24 | 中煤科工集团西安研究院有限公司 | Sectional composite coal drawing method for ground horizontal well |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN111980706A (en) * | 2020-09-02 | 2020-11-24 | 中煤科工集团西安研究院有限公司 | Sectional composite coal drawing method for ground horizontal well |
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