CN112523707B - Coal and gas outburst danger prediction while drilling device and prediction method thereof - Google Patents
Coal and gas outburst danger prediction while drilling device and prediction method thereof Download PDFInfo
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- 238000005553 drilling Methods 0.000 title claims abstract description 58
- 239000003245 coal Substances 0.000 title claims abstract description 44
- 238000000034 method Methods 0.000 title claims abstract description 27
- 230000007246 mechanism Effects 0.000 claims abstract description 99
- 230000006835 compression Effects 0.000 claims abstract description 24
- 238000007906 compression Methods 0.000 claims abstract description 24
- 239000002775 capsule Substances 0.000 claims abstract description 23
- 238000005259 measurement Methods 0.000 claims description 16
- 230000008569 process Effects 0.000 claims description 12
- 239000002817 coal dust Substances 0.000 claims description 8
- 230000009471 action Effects 0.000 claims description 7
- 239000012535 impurity Substances 0.000 claims description 4
- 238000004364 calculation method Methods 0.000 claims description 3
- 230000003247 decreasing effect Effects 0.000 claims 1
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- 206010063385 Intellectualisation Diseases 0.000 description 2
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- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000008859 change Effects 0.000 description 1
- 238000003795 desorption Methods 0.000 description 1
- 239000000411 inducer Substances 0.000 description 1
- 238000005065 mining Methods 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
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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
- E21B21/00—Methods or apparatus for flushing boreholes, e.g. by use of exhaust air from motor
- E21B21/12—Methods or apparatus for flushing boreholes, e.g. by use of exhaust air from motor using drilling pipes with plural fluid passages, e.g. closed circulation systems
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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
- E21B21/00—Methods or apparatus for flushing boreholes, e.g. by use of exhaust air from motor
- E21B21/10—Valve arrangements in drilling-fluid circulation systems
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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
- E21B21/00—Methods or apparatus for flushing boreholes, e.g. by use of exhaust air from motor
- E21B21/10—Valve arrangements in drilling-fluid circulation systems
- E21B21/103—Down-hole by-pass valve arrangements, i.e. between the inside of the drill string and the annulus
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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
- E21B21/00—Methods or apparatus for flushing boreholes, e.g. by use of exhaust air from motor
- E21B21/16—Methods or apparatus for flushing boreholes, e.g. by use of exhaust air from motor using gaseous fluids
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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
- E21B33/00—Sealing or packing boreholes or wells
- E21B33/10—Sealing or packing boreholes or wells in the borehole
- E21B33/12—Packers; Plugs
- E21B33/1208—Packers; Plugs characterised by the construction of the sealing or packing means
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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
- E21B33/00—Sealing or packing boreholes or wells
- E21B33/10—Sealing or packing boreholes or wells in the borehole
- E21B33/12—Packers; Plugs
- E21B33/126—Packers; Plugs with fluid-pressure-operated elastic cup or skirt
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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
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/006—Production of coal-bed methane
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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
- E21B49/00—Testing the nature of borehole walls; Formation testing; Methods or apparatus for obtaining samples of soil or well fluids, specially adapted to earth drilling or wells
- E21B49/08—Obtaining fluid samples or testing fluids, in boreholes or wells
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Abstract
The invention relates to a coal and gas outburst danger prediction while drilling device and a prediction method thereof, which sequentially comprise a hollow drill bit, a hole bottom plugging mechanism, a double-arm drill rod and an airflow guiding mechanism, wherein the top end of the drill bit is provided with an air outlet; the hole bottom plugging mechanism comprises an outer pipe and an inner pipe fixedly installed on the inner wall of the front end of the outer pipe, an expansion capsule is fixedly installed on the outer wall of the outer pipe at the expansion hole on the outer pipe on the rear side of the inner pipe, a baffle plate in threaded connection with a rotating screw is fixedly installed in the outer pipe on the front side of a second vent hole on the front side of the inner pipe, a compression spring is sleeved on the rotating screw, and a hole plugging piece used for freely plugging a first vent hole is fixedly installed at the tail end of the rotating screw; an airflow guide valve and an air supply tail connector are fixedly arranged on one side of the airflow guide mechanism, which is far away from the drill bit; the parameter measuring mechanism is communicated with a central pipe of an inner cavity of the double-arm drill rod, and a pressure gauge is connected to an annular cavity of the double-arm drill rod, so that the problem that the emergent danger of the working surface at the present stage cannot be predicted in real time while drilling is solved.
Description
Technical Field
The invention belongs to the field of coal mine safety, and relates to a coal and gas outburst danger prediction while drilling device and a prediction method thereof.
Background
Coal and gas outburst accidents are one of the main disasters faced by a production mine, the loss and the influence brought to the coal mine industry are huge, and the effective prevention and control of the coal and gas outburst accidents are always the mission key and the technical difficulty of the outburst mine. Because of numerous outburst inducers and complicated outburst mechanism, the method mainly adopts a mode of 'parameter measurement drilling construction-coal sample collection-parameter measurement' to calculate the prediction index value and realize the prediction of coal and gas outburst risks at present. However, along with the increase of the mining depth of a mine year by year, the complexity of geological conditions is aggravated, the regular change of gas content and gas pressure is not obvious, the loss of gas cannot be collected when coal dust is initially broken in the coal sample acquisition process, the accuracy of a gas desorption rule model, the applicability of a prediction index critical value and the sensitivity of the index when a coal body is exposed to the completion of coal sample acquisition are all problems required to be solved by the current prediction method, meanwhile, the traditional coal and gas outburst prediction method needs the procedures of drilling in advance, coal sample acquisition and the like, the measurement process is complicated, professional technicians need to follow up with the duty to measure, a certain production time is occupied, the automatic and intelligent development direction of a new era in the coal mine industry is not met, and therefore, in order to realize the efficient production of the mine, the outburst risk prediction device and method while drilling need urgently, and the outburst risk integrated prediction of the drilling process can be realized, the prediction link is simplified, the personnel investment and the labor cost are reduced, and a foundation is laid for highlighting the automation and the intellectualization of the prediction.
Disclosure of Invention
In view of the above, the invention provides a coal and gas outburst risk prediction while drilling device and a prediction method thereof, in order to solve the problem that the outburst risk of the working face cannot be predicted in real time while drilling at the present stage.
In order to achieve the purpose, the invention provides the following technical scheme: a coal and gas outburst danger while-drilling prediction device sequentially comprises a hollow drill bit, a hole bottom plugging mechanism, a double-arm drill rod and an airflow guide mechanism which are detachably and fixedly connected, wherein a pipeline on the airflow guide mechanism is connected with a parameter measurement mechanism; the top end of the drill bit is provided with an air outlet;
the hole bottom plugging mechanism comprises an outer pipe and an inner pipe fixedly installed on the inner wall of the front end of the outer pipe, a cavity of the inner pipe is a first air vent, the length of the inner pipe is smaller than that of the outer pipe, an expansion hole is formed in the outer pipe on the rear side of the inner pipe, an expansion capsule is fixedly installed on the outer wall of the outer pipe at the expansion hole, a second air vent is formed in the outer pipe on the front side of the inner pipe, a baffle plate in threaded connection with a rotating screw is fixedly installed in the outer pipe on the front side of the second air vent, a compression spring is sleeved on the rotating screw, and a plugging piece used for freely plugging the first air vent is fixedly installed at the tail end of the rotating screw;
an airflow guide valve and an air supply tail braid interface are fixedly arranged on one side of the airflow guide mechanism, which is far away from the drill bit;
the air flow guide mechanism communicated with the inner cavity of the double-arm drill rod is a central pipe, the air flow guide mechanism communicated with the annular cavity of the double-arm drill rod is an annular space, the parameter measuring mechanism is communicated with the central pipe, and the annular space is connected with a pressure gauge.
The beneficial effect of this basic scheme lies in: the hole plugging piece in the hole bottom plugging mechanism is fixed at one end of a compression spring, the other end of the compression spring is connected with a rotating screw, and the rotating screw is fixed between an inner pipe and an outer pipe through threads to form an elastic structure. The compression spring can be driven to compress and expand by rotating the rotating screw, so that the elasticity of the compression spring is changed; the rotary screw screwing degree is adjusted according to the air pressure of the underground working face of the coal mine, so that the compression action of the compression spring is completed after certain pressure is met, and the first vent hole is communicated.
Furthermore, the airflow guide mechanism also comprises a drill rod connecting rod piece in threaded connection with the double-arm drill rods, a central pipe airflow interface with a central pipe airflow interface switch is arranged on the drill rod connecting rod piece connected with the inner double-arm drill rod, and an annular space airflow interface with an annular space airflow interface switch is arranged on the drill rod connecting rod piece connected with the outer double-arm drill rod.
Further, parameter measurement mechanism and center tube pass through the rubber tube intercommunication, and parameter measurement mechanism still includes the casing, installs air inlet and gas outlet on the casing and sets up in inside gas concentration sensor, time-recorder, data processor, display screen, the power supply group battery of casing.
Furthermore, the airflow guide valve comprises a guide disc B and a guide disc C which rotate relatively, the guide disc B and the guide disc C are evenly and alternately divided into a plurality of sector areas along a central angle, the stop dog of each sector area, which is opposite to the central pipe, is a sector block, the stop dog, which is opposite to the annular space, is an arc block, the sector blocks and the arc blocks on the guide disc B are arranged in a staggered mode, and the sector blocks on the guide disc C are arranged opposite to the arc blocks. Has the beneficial effects that: by rotating the guide disk B and the guide disk C on the airflow guide valve, the air flow can be controlled to independently enter the drill rod from the annular space or independently enter the drill rod from the central pipe.
Furthermore, the outer wall of the outer pipe at the expansion hole is provided with a groove, and the expansion capsule is clamped in the groove in an inwards concave mode. Has the advantages that: the expansion capsule is clamped in the groove in an inwards concave mode, so that the effect of protecting the expansion capsule can be achieved, and the expansion capsule is prevented from being damaged when coal dust at the bottom of the hole is conveyed along the gap between the outer wall of the device and the hole wall.
Further, the tail end of the drill bit is provided with 2 layers of threads which are in threaded connection with a hole bottom plugging mechanism. Has the beneficial effects that: the connection stability of the drill bit and the hole bottom plugging mechanism is enhanced.
A prediction method of a coal and gas outburst risk prediction while drilling device is based on the coal and gas outburst risk prediction while drilling device and specifically comprises the following steps:
s1, adjusting the rotary screw according to the underground wind pressure to ensure that the first vent hole can be opened after the expansion capsule is fully expanded, namely the pressure for the complete expansion of the expansion capsule is P1, and the pressure for the opening of the first vent hole is P2 by the wind pressure, which satisfies the condition that P2 is more than P1;
s2, sequentially connecting a drill bit, a hole bottom plugging mechanism, a double-arm drill rod and an airflow guide mechanism in a threaded connection mode, connecting an air supply tail braid at an air supply tail braid interface at the tail end of the airflow guide mechanism, closing an interface switch of the airflow guide mechanism, and simultaneously adjusting an airflow guide valve to ensure that compressed air is conveyed to the hole bottom only through a double-arm drill rod central tube and an inner tube of the hole bottom plugging mechanism to start normal drilling, and conveying coal scraps at the hole bottom to the outside of the hole through a gap between the outer wall of the device and the wall of the hole;
s3, after the coal is drilled to the specified position, stopping drilling and continuing air supply for 3min to blow off coal dust impurities in the inlet hole; continuing to drill forward for 1m, stopping drilling, immediately opening an interface switch of the airflow guide mechanism, connecting the airflow guide mechanism with an upper parameter measuring mechanism, simultaneously adjusting an airflow guide valve to control the air pressure to reach the bottom of the hole only through the annular space of the dual-arm drill rod and the hole bottom plugging mechanism, giving constant pressure to supply air continuously, wherein the air supply pressure is not less than P1, after the expansion capsule completes the expansion action, the compression spring is influenced by the pressure to open the air vent under the action of the continuous air pressure to form a loop, and the gas desorbed from the freshly exposed coal dust at the bottom of the hole flows through the parameter measuring mechanism along with the air flow through the central pipe;
s4, collecting data in the wind flow by a gas concentration sensor and a timer in the parameter measuring mechanism, accessing the data into a data processor, calculating by using a prediction algorithm, and outputting and displaying a calculation result on a display screen;
s5: after the measurement process is finished, air supply is stopped, the connection between the parameter measurement mechanism and the airflow guide mechanism is disconnected, pressure relief and the restoration of the expansion capsule and the compression spring are finished in the while-drilling prediction device, an interface switch of the airflow guide mechanism is closed, forward drilling is continued, and while-drilling prediction is achieved.
Further, the prediction algorithm adopted in step S4 is:
establishing a prediction index system: y → [ T1, T2, (1-X)/T2]
Wherein Y is a prediction index system; t1 is the duration/s of the gas concentration in the determination process being 100%; t2 is the duration/s for the gas concentration to decrease from 100% to be stable; the concentration of the gas in the wind flow is X when the concentration is stable;
taking the gas content value and the critical value of a measurement-while-drilling site as standards, investigating and establishing the critical values of prediction indexes T1, T2 and (1-X)/T2 on site, and judging that the outburst risk exists when 3 indexes exceed the critical values.
The invention has the beneficial effects that:
1. the invention discloses a coal and gas outburst danger while drilling prediction device which mainly comprises a drill bit, a hole bottom plugging mechanism, two-arm drill rods, an airflow guide mechanism and a parameter measurement mechanism. In the normal drilling process of the drill bit, the air flow guide valve is controlled to enable compressed air to be conveyed to the bottom of a hole through the central pipe of the double-arm drill pipe and the inner pipe of the hole bottom plugging mechanism, then coal scraps at the bottom of the hole are conveyed out of the hole through a gap between the outer wall of the device and the hole wall, drilling is stopped after the drill bit is drilled to a specified position, air supply is continued to blow off impurities of the coal scraps in the hole, the drill bit drills forwards for 1m, then the parameter measuring mechanism is connected, the air flow guide valve is operated to control air pressure to reach the bottom of the hole only through the annular space of the double-arm drill pipe and the hole bottom plugging mechanism, constant air pressure is given to supply air continuously, the expansion capsule is expanded to complete sealing between the hole bottom plugging mechanism and the hole wall, the compression spring is influenced by the continuous air pressure, then the air vent is opened to form a loop, gas flow in the hole flows through the parameter measuring mechanism through the central pipe, and finally the gas concentration gradient of the coal scraps is exposed freshly at the bottom of the hole, And establishing a coal and gas outburst while-drilling prediction system according to the relation between the concentration and the time of the gas. The whole prediction device has the advantages of compact and reasonable structure, convenient operation, good dynamic performance, high accuracy and stable and reliable measurement result, the measurement result can reflect the gas flow distribution along the way in the continuous drilling process, and the prediction device has wide practicability.
2. The coal and gas outburst danger prediction while drilling device disclosed by the invention can realize the outburst danger prediction while drilling in the drilling process, simplify the outburst prediction flow in the current stage, reduce the personnel investment, improve the production efficiency, reduce the production cost of a mine, and accord with the development direction of automation and intellectualization of the outburst prediction.
Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages of the invention may be realized and attained by the means of the instrumentalities and combinations particularly pointed out hereinafter.
Drawings
For the purposes of promoting a better understanding of the objects, aspects and advantages of the invention, reference will now be made to the following detailed description taken in conjunction with the accompanying drawings in which:
FIG. 1 is a schematic structural diagram of a coal and gas outburst risk prediction while drilling device according to the present invention;
FIG. 2 is a schematic structural diagram of a hole bottom plugging mechanism in the coal and gas outburst risk while drilling prediction device according to the invention;
FIG. 3 is a cross-sectional view taken along line A-A of FIG. 1 in accordance with the present invention;
FIG. 4 is a cross-sectional view taken along line B-B of FIG. 1 in accordance with the present invention;
fig. 5 is a cross-sectional view taken along line C-C of fig. 1 in accordance with the present invention.
Reference numerals are as follows: the device comprises a drill bit 1, an air outlet 1-1, a hole bottom plugging mechanism 2, an expansion capsule 2-1, an expansion hole 2-2, a first vent hole 2-3, a second vent hole 2-4, a hole plugging sheet 2-5, a compression spring 2-6, a rotary screw 2-7, a double-arm drill rod 3, an air flow guide mechanism 4, a drill rod connecting rod piece 4-1, an air flow guide valve 4-2, an air supply tail braid interface 4-3, a central tube air flow interface 4-4, an annular space air flow interface 4-5, a central tube air flow interface switch 4-6, an annular space air flow interface switch 4-7, a parameter measuring mechanism 5, a shell 5-1, a rubber tube 5-2, a pressure gauge 5-3, an air inlet 5-4 and an air outlet 5-5.
Detailed Description
The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be easily understood by those skilled in the art from the disclosure of the present specification. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention.
The coal and gas outburst danger while-drilling prediction device sequentially comprises a hollow drill bit 1, a hole bottom plugging mechanism 2, a double-arm drill rod 3 and an airflow guide mechanism 4 which are in threaded connection, wherein 2 layers of threads are arranged at the tail end of the drill bit 1 and are in threaded connection with the hole bottom plugging mechanism 2. The airflow guide mechanism 4 is connected with a parameter measuring mechanism 5 through a rubber pipe 5-2. The top end of the drill bit 1 is provided with an air outlet 1-1.
The hole bottom plugging mechanism 2 comprises an outer pipe and an inner pipe fixedly arranged on the inner wall of the front end of the outer pipe, the cavity of the inner pipe is a first air vent 2-3, the length of the inner pipe is smaller than that of the outer pipe, an expansion hole 2-2 is formed in the outer pipe on the rear side of the inner pipe, an expansion capsule 2-1 is fixedly arranged on the outer wall of the outer pipe at the position of the expansion hole 2-2, a second air vent 2-4 is formed in the outer pipe on the front side of the inner pipe, a baffle plate in threaded connection with a rotating screw 2-7 is fixedly arranged in the outer pipe on the front side of the second air vent 2-4, a compression spring 2-6 is sleeved on the rotating screw 2-7, and a hole plugging piece 2-5 for freely plugging the first air vent 2-3 is fixedly arranged at the tail end of the rotating screw 2-7; the hole plugging piece 2-5 in the hole bottom plugging mechanism 2 is fixed at one end of a compression spring 2-6, the other end of the compression spring 2-6 is connected with a rotary screw 2-7, and the rotary screw 2-7 is fixed between an inner pipe and an outer pipe through threads to form an elastic structure. The compression springs 2-6 can be driven to compress and expand by rotating the rotary screws 2-7, so that the elasticity of the compression springs 2-6 is changed; the screwing degree of the rotary screws 2-7 is adjusted according to the air pressure of the underground working face of the coal mine, so that the compression springs 2-6 complete compression after certain pressure and are communicated with the first vent holes 2-3.
An airflow guide valve 4-2 and an air supply tail connector 4-3 are fixedly arranged on one side of the airflow guide mechanism 4, which is far away from the drill bit 1; the airflow guide mechanism 4 further comprises a drill rod connecting rod piece 4-1 in threaded connection with the double-arm drill rod 3, a central pipe airflow interface 4-4 with a central pipe airflow interface 4-4 switch is arranged on the drill rod connecting rod piece 4-1 connected with the inner double-arm drill rod 3, and an annular space airflow interface 4-5 with an annular space airflow interface 4-5 switch is arranged on the drill rod connecting rod piece 4-1 connected with the outer double-arm drill rod 3.
The airflow guide valve 4-2 comprises a guide disc B and a guide disc C which rotate relatively, the guide disc B and the guide disc C are uniformly and alternately separated into a plurality of sector areas along a central angle, a stop block of each sector area, which is opposite to the central pipe, is a sector block, a stop block, which is opposite to the annular space, is an arc block, the sector blocks and the arc blocks on the guide disc B are arranged in a staggered mode, and the sector blocks on the guide disc C are arranged opposite to the arc blocks. By rotating the guide disk B and the guide disk C on the airflow guide valve 4-2, the air flow can be controlled to independently enter the drill rod from the annular space or independently enter the drill rod from the central pipe.
The air flow guide mechanism 4 communicated with the inner cavity of the double-arm drill rod 3 is a central pipe, the air flow guide mechanism 4 communicated with the annular cavity of the double-arm drill rod 3 is an annular space, and the annular space is connected with a pressure gauge 5-3. The parameter measuring mechanism 5 is communicated with the central pipe through a rubber pipe 5-2, and the parameter measuring mechanism 5 further comprises a shell 5-1, an air inlet 5-4 and an air outlet 5-5 which are arranged on the shell 5-1, and a gas concentration sensor, a timer, a data processor, a display screen and a power supply battery pack which are arranged inside the shell 5-1.
A prediction method of a coal and gas outburst risk while drilling prediction device is carried out on the basis of the coal and gas outburst risk while drilling prediction device, and specifically comprises the following steps:
s1, adjusting the rotary screw 2-7 according to the underground wind pressure, ensuring that the first vent hole 2-3 can be opened after the expansion capsule 2-1 is fully expanded, namely the pressure of the expansion capsule 2-1 which is fully expanded is P1, and ensuring that the pressure of the first vent hole 2-3 which is opened is P2 by the wind pressure, wherein the pressure is required to be P2 > P1;
s2, sequentially connecting a drill bit 1, a hole bottom plugging mechanism 2, a double-arm drill rod 3 and an airflow guide mechanism 4 in a threaded connection mode, connecting an air supply tail braid at an air supply tail braid interface 4-3 at the tail end of the airflow guide mechanism 4, closing an interface switch of the airflow guide mechanism 4, and simultaneously adjusting an airflow guide valve 4-2 to ensure that compressed air is conveyed to the hole bottom only through a central tube of the double-arm drill rod 3 and an inner tube of the hole bottom plugging mechanism 2 to start normal drilling, and conveying hole bottom coal scraps to the outside of the hole through a gap between the outer wall of the device and the hole wall;
s3, after drilling to a specified position, stopping drilling and continuing air supply for 3min to blow off coal dust impurities in the inlet hole; then, continuously drilling for 1m forwards to stop drilling, immediately opening an interface switch of an airflow guide mechanism 4 and connecting a parameter measuring mechanism 5, simultaneously adjusting an airflow guide valve 4-2 to control the air pressure to reach the bottom of the hole only through annular spaces of a double-arm drill rod 3 and a hole bottom plugging mechanism 2, giving constant pressure to supply air continuously, wherein the air supply pressure is not less than P1, after the expansion capsule 2-1 completes the expansion action, a compression spring 2-6 is influenced by pressure to open a drill rod through an air hole under the action of the continuous air pressure to form a loop, and the gas desorbed from the fresh exposed coal dust at the bottom of the hole flows through the parameter measuring mechanism 5 along with the air flow through a central pipe;
s4, collecting data in the wind flow by a gas concentration sensor and a timer in the parameter measuring mechanism 5, accessing the data into a data processor, calculating by using a prediction algorithm, and outputting and displaying a calculation result on a display screen;
the prediction algorithm is as follows:
establishing a prediction index system: y → [ T1, T2, (1-X)/T2]
Wherein Y is a prediction index system; t1 is the duration/s of the gas concentration in the determination process being 100%; t2 is the duration/s for the gas concentration to decrease from 100% to be stable; when the gas concentration in the wind flow is stable, the concentration is X;
taking the gas content value and the critical value of a measurement-while-drilling site as standards, investigating and establishing the critical values of prediction indexes T1, T2 and (1-X)/T2 on site, and judging that the outburst risk exists when 3 indexes exceed the critical values.
S5: after the measurement process is finished, air supply is stopped, the connection between the parameter measurement mechanism 5 and the airflow guide mechanism 4 is disconnected, pressure relief and the resetting of the expansion capsule 2-1 and the compression spring 2-6 are finished in the while-drilling prediction device, an interface switch of the airflow guide mechanism 4 is closed, forward drilling is continued, and while-drilling prediction is achieved.
Finally, the above embodiments are only intended to illustrate the technical solutions of the present invention and not to limit the present invention, and although the present invention has been described in detail with reference to the preferred embodiments, it will be understood by those skilled in the art that modifications or equivalent substitutions may be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions, and all of them should be covered by the claims of the present invention.
Claims (7)
1. A coal and gas outburst danger while-drilling prediction device is characterized by comprising a hollow drill bit, a hole bottom plugging mechanism, a double-arm drill rod and an airflow guide mechanism which are detachably and fixedly connected, wherein the airflow guide mechanism is connected with a parameter measuring mechanism; the top end of the drill bit is provided with an air outlet;
the hole bottom plugging mechanism comprises an outer pipe and an inner pipe fixedly installed on the inner wall of the front end of the outer pipe, the cavity of the inner pipe is a first air vent, the length of the inner pipe is smaller than that of the outer pipe, an expansion hole is formed in the outer pipe on the rear side of the inner pipe, an expansion capsule is fixedly installed on the outer wall of the outer pipe at the expansion hole, a second air vent is formed in the outer pipe on the front side of the inner pipe, a baffle plate in threaded connection with a rotating screw is fixedly installed in the outer pipe on the front side of the second air vent, a compression spring is sleeved on the rotating screw, and a hole plugging sheet used for freely plugging the first air vent is fixedly installed at the tail end of the rotating screw;
an airflow guide valve and an air supply tail connector are fixedly arranged on one side of the airflow guide mechanism, which is far away from the drill bit;
the air flow guide mechanism also comprises a drill rod connecting rod piece in threaded connection with the double-arm drill rod, the air flow guide mechanism communicated with the inner cavity of the double-arm drill rod is a central pipe, the air flow guide mechanism communicated with the annular cavity of the double-arm drill rod is an annular space, and the parameter measuring mechanism is communicated with the central pipe; a drill rod connecting rod piece connected with the drill rods at the inner sides of the two arms of drill rods is provided with a central pipe airflow interface switch, and a drill rod connecting rod piece connected with the drill rods at the outer sides of the two arms of drill rods is provided with an annular space airflow interface switch; the annular space is connected with a pressure gauge.
2. The device for predicting the coal and gas outburst risk while drilling as claimed in claim 1, wherein the parameter measuring mechanism is communicated with the central pipe through a rubber pipe, and further comprises a shell, an air inlet and an air outlet which are arranged on the shell, and a gas concentration sensor, a timer, a data processor, a display screen and a power supply battery pack which are arranged inside the shell.
3. The coal and gas outburst risk while drilling prediction device according to claim 1, wherein the airflow guiding valve comprises a guiding disc B and a guiding disc C which rotate relatively, the guiding disc B and the guiding disc C are evenly and alternately divided into a plurality of sectors along a central angle, a stop block of each sector opposite to the central pipe is a sector, a stop block opposite to the annular space is an arc-shaped block, the sectors and the arc-shaped blocks on the guiding disc B are arranged in a staggered mode, and the sectors and the arc-shaped blocks on the guiding disc C are arranged oppositely.
4. The device for predicting coal and gas outburst danger while drilling as recited in claim 1, wherein a groove is formed on the outer wall of the outer pipe at the expansion hole, and the expansion capsule is clamped in the groove in an inwards concave manner.
5. The device for predicting the coal and gas outburst risk while drilling as claimed in claim 1, wherein the tail end of the drill bit is provided with 2 layers of threads which are in threaded connection with a hole bottom plugging mechanism.
6. A prediction method of a coal and gas outburst risk prediction while drilling device is characterized by comprising the following steps:
s1, adjusting the rotary screw according to the underground wind pressure, wherein the underground wind pressure ensures that the first vent hole can be opened after the expansion capsule is fully expanded, the pressure for the expansion capsule to be fully expanded is P1, the pressure for the first vent hole to be opened by the wind pressure is P2, and the requirement that P2 is more than P1 is met;
s2, sequentially connecting a drill bit, a hole bottom plugging mechanism, a double-arm drill rod and an airflow guide mechanism in a threaded connection mode, connecting an air supply tail braid at an air supply tail braid interface at the tail end of the airflow guide mechanism, closing an interface switch of the airflow guide mechanism, and simultaneously adjusting an airflow guide valve to ensure that air pressure is only conveyed to the hole bottom through a double-arm drill rod central tube and an inner tube of the hole bottom plugging mechanism to start normal drilling, and conveying coal scraps at the hole bottom to the outside of the hole through a gap between the outer wall of the device and the wall of the hole;
s3, after drilling to a specified position, stopping drilling and continuing air supply for 3min to blow off coal dust impurities in the inlet hole; then continuously drilling forward for 1m to stop drilling, immediately opening an interface switch of the airflow guide mechanism and connecting the airflow guide mechanism with an upper parameter measuring mechanism, simultaneously adjusting an airflow guide valve to control the air pressure to reach the bottom of the hole only through the annular space of the double-arm drill rod and the annular space of the hole bottom plugging mechanism, giving constant pressure to continuously supply air, wherein the air supply pressure is not less than P1, after the expansion capsule finishes the expansion action, the compression spring is influenced by pressure to open the drill rod through the first vent hole under the action of the continuous air pressure to form a loop, and the gas desorbed from the fresh exposed coal dust at the bottom of the hole flows through the parameter measuring mechanism along with the air flow through the central pipe;
s4, collecting data in wind flow by a gas concentration sensor and a timer in the parameter measuring mechanism, accessing the data into a data processor, calculating by using a prediction algorithm, and outputting and displaying a calculation result on a display screen;
s5: after the measurement process is finished, air supply is stopped, the connection between the parameter measurement mechanism and the airflow guide mechanism is disconnected to finish pressure relief, the expansion capsule and the compression spring are reset, an interface switch of the airflow guide mechanism is closed to continue forward drilling, and prediction while drilling is achieved.
7. The prediction method of the coal and gas outburst risk while drilling prediction device according to claim 6, wherein the prediction algorithm adopted in step S4 is as follows:
establishing a prediction index system: y → [ T1, T2, (1-X)/T2]
Wherein Y is a prediction index system; t1 is the duration/s of the gas concentration in the determination process being 100%; t2 is the duration/s of the gas concentration decreasing from 100% to stable; the concentration of the gas in the wind flow is X when the concentration is stable;
the method is characterized in that the gas content value of a measurement while drilling site and a critical value thereof are taken as standards, the critical values of prediction indexes T1, T2 and (1-X)/T2 are considered and established on site, and when 3 indexes exceed the critical values, the outburst risk is judged.
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| CN114233203B (en) * | 2021-11-22 | 2023-09-26 | 煤炭科学技术研究院有限公司 | Switch device installed on drill rod wall and controlled by wind pressure to open and close state and drill rod |
| CN114718445B (en) * | 2022-03-28 | 2024-08-09 | 中煤科工集团重庆研究院有限公司 | Drilling and punching integrated system and method |
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