A gas concentration early warning method for coal roadway driving face based on pre-drainage roadway extraction drilling

Abstract

The application relates to a kind of coal lane excavation working face gas concentration early warning methods based on pre-extraction lane extraction drilling, comprising data acquisition system (single-hole gas precision metering), gas concentration analysis module, ground stress analysis module and gas overrun early warning module;The method obtains the gas concentration of the coal lane excavation working face in real time, extracts the gas monitoring value of the current time M t Before the current time T 1 、 T 2 Time period gas monitoring data and extraction coal seam roof strata ground stress monitoring data with drilling;Calculate gas monitoring index N t 、 P t When the index N t Is greater than threshold value N 0 , gas overrun short-term early warning.The application realizes the dynamic intelligent early warning of the gas concentration overrun of the coal lane excavation working face, effectively guarantees the safety production of the coal mine.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of gas disaster prediction, and particularly relates to a coal roadway tunneling working face gas concentration early warning method based on pre-drainage roadway drainage drilling. BACKGROUND

[0002] Under the influence of factors such as buried depth, high ground stress and high ground temperature, deep coal mining faces problems such as increased gas emission, increased gas pressure and abnormal emission of local gas burst, which directly leads to increased threat of gas disasters in mines. Coal mine gas outburst accidents mainly occur at coal roadway tunneling working faces. Coal mine gas overrun is an abnormal phenomenon in which the gas concentration in the underground working environment exceeds the specified safety limit. Gas overrun can easily lead to coal and gas outburst, gas explosion and other disastrous accidents, so avoiding gas accumulation or gas overrun is a key link in preventing coal and gas outburst and gas explosion, and is also a necessary means to provide a good working environment for workers. In order to prevent such accidents, coal mines are generally equipped with safety monitoring systems to realize online monitoring of the gas concentration in key areas underground and automatic alarm after gas overrun.

[0003] Gas overrun prevention is a key link in coal mine gas disaster prevention, and there are many influencing factors of gas disasters, complex causes and easy formation of coupled disasters. The existing gas concentration monitoring equipment and means cannot realize accurate early warning of gas disasters, and there are problems such as single measurement parameter, inaccurate measurement and untimely response. Therefore, an intelligent method for predicting gas concentration overrun at the working face by combining various gas monitoring data is urgently needed. SUMMARY

[0004] The present application aims to overcome the above-mentioned deficiencies and provide a coal roadway tunneling working face gas concentration early warning method based on pre-drainage roadway drainage drilling. Through intelligent analysis of high-precision low-gas flow monitoring data of drainage drilling and ground stress monitoring data while drilling, non-contact continuous intelligent early warning of gas concentration overrun risk at the coal mine tunneling working face is realized, which is beneficial to the advanced prevention and control of coal mine gas accidents.

[0005] The purpose of the present application is achieved as follows:

[0006] A coal roadway tunneling working face gas concentration early warning method based on pre-drainage roadway drainage drilling, comprising the following contents:

[0007] S1, using pre-drainage roadway drainage drilling;

[0008] A drill rig is used to drill a through-hole in the tunneling roadway in the coal seam from the drill field of the high drainage roadway or the bottom drainage roadway, and the hole arrangement position is the working face of the entire tunneling roadway and the to-be-tunneling roadway, including the 15m range outside the profile lines of the two roadways.

[0009] S2. Install a single-hole gas precision meter and a drilling stress measuring instrument;

[0010] Install single-hole gas precision metering instruments and drilling stress measuring instruments in all cross-layer boreholes within a drilling area of ​​3 drilling sites ahead of the current location of the tunneling machine;

[0011] S3. Install the gas concentration analysis module, the ground stress analysis module, and the gas over-limit early warning module;

[0012] The drilling rig is connected to a gas over-limit early warning module, which is connected to a ground stress analysis module and a gas concentration analysis module. The ground stress analysis module is connected to each drilling-while-drilling ground stress measuring instrument, and the gas concentration analysis module is connected to each single-hole gas precision metering instrument. Thus, while extracting gas, the single-hole gas precision metering data and the ground stress drilling-while-drilling measurement data are obtained in real time.

[0013] S4. Real-time acquisition of gas monitoring data within the entire coal roadway excavation face and gas monitoring data from at least three advanced drilling sites, including a 15 m range outside the outline of the two roadways.

[0014] S5. Extract the current gas monitoring value. M t Compared to the current moment T 1 , T 2 Gas monitoring data over a specific time period;

[0015] S6, according to T Gas monitoring data over a time period, and the gas concentration analysis module calculates the following indicators. N t ;

[0016] index N t The average value of gas monitoring data over time period T1 prior to the current moment is calculated as follows:

[0017] ;

[0018] Short-term gas over-limit warning threshold N 0 Take the time before the current moment T 1 Time period indicators N t ;

[0019] S7, according to T Gas monitoring data over two time periods; gas concentration analysis module calculates indicators. P t ;

[0020] indexP t Before the current moment T 2 The average value of gas monitoring data over a period of time, indicators P t The calculation method is as follows:

[0021] ;

[0022] in, y i for T Gas monitoring data of the working face at different times within the 2-period time period; v For the working face advance speed; l The distance the working face advances;

[0023] S8, When the indicator N t Greater than the threshold N At 0:00, a short-term warning for excessive gas levels is issued; when the gas monitoring value... M t Greater than the threshold M At 0:00, an emergency warning for excessive gas levels will be issued;

[0024] S9. As the tunneling face advances, repeat steps S5 to S8 to provide dynamic real-time early warning of excessive gas levels at the working face.

[0025] Furthermore, in step S1, the spacing between the boreholes 5 is 2R, where R is the borehole extraction radius.

[0026] Furthermore, in step S1, a drilling site is arranged every 4 to 6 rows of cross-layer boreholes, and the distance between each drilling site does not exceed 10 m.

[0027] Furthermore, the single-hole gas precision meter is installed in the middle of the cross-layer borehole, and the drilling stress measuring instrument is installed on the coal seam.

[0028] Furthermore, the time period in step S5 T 1 represents 15-20 minutes; time period T 2. Determined based on the working face advance speed.

[0029] Furthermore, this step is repeated continuously in step S6, if the index N t Greater than the threshold N 0, issue a short-term warning for gas exceeding the limit for 10 to 15 minutes; if two or more short-term warnings for gas exceeding the limit are issued consecutively, immediately implement gas-electric interlocking operation.

[0030] Furthermore, the threshold in step S8 M 0 takes the time before the current moment.T 2 Average value of gas monitoring data over a period of time P t 200% of, that is:

[0031] ;

[0032] If the current gas monitoring value M t Greater than M If the value is 0, an emergency warning for excessive gas levels will be issued, and gas-electric interlocking operations will be immediately implemented.

[0033] Furthermore, the gas concentration range obtained from the precise metering data of a single gas well is 0~100%.

[0034] Compared with the prior art, the beneficial effects of the present invention are:

[0035] This invention enables in-depth analysis of mine gas monitoring data and ground stress monitoring data during drilling. By real-time monitoring and analysis of gas parameters and ground stress parameters from at least three drilling sites ahead of the working face of the tunnel (including a 15-m radius outside the outline of the two tunnels), it achieves precise single-hole metering of gas drainage boreholes and ground stress monitoring during drilling. Based on gas and ground stress monitoring data, this invention collaboratively monitors the gas flow rate in the tunnel, enabling real-time early warning of gas exceeding limits in the tunnel and effectively ensuring mine production safety. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the layout inside the drilling site according to Embodiment 1 of the present invention.

[0037] Figure 2 This is a schematic diagram of the perforation plan of Embodiment 1 of the present invention.

[0038] Figure 3 This is a front view of the perforation layout in Embodiment 1 of the present invention.

[0039] Figure 4 This is a side view of the perforation pattern in Embodiment 1 of the present invention.

[0040] Figure 5 This is a schematic diagram of the layout inside the drilling site according to Embodiment 2 of the present invention.

[0041] Figure 6 This is a schematic diagram of the perforation plan of Embodiment 2 of the present invention.

[0042] Figure 7 This is a front view of the perforation layout in Embodiment 2 of the present invention.

[0043] in:

[0044] 1. Excavation roadway; 2. Drilling site; 3. Cross-layer borehole; 4. Roadway to be excavated; 5. High-speed drainage roadway; 6. Advanced drilling site; 7. Coal seam; 8. Single-hole gas precision meter; 9. Drilling stress measuring instrument; 10. Directional drilling rig; 11. Stress analysis module; 12. Gas concentration analysis module; 13. Gas over-limit early warning module; 14. Bottom drainage roadway. Detailed Implementation

[0045] To better understand the technical solution of the present invention, a detailed description will be provided below in conjunction with relevant illustrations. It should be understood that the specific embodiments described below are not intended to limit the specific implementation of the technical solution of the present invention, but are merely possible implementations of the technical solution of the present invention. It should be noted that the descriptions of the positional relationships of the components herein, such as component A being located above component B, are based on the relative positions of the components in the illustrations and are not intended to limit the actual positional relationships of the components. Example 1

[0046] See Figures 1-4 , Figure 1 A schematic diagram of the drilling site layout for a gas concentration early warning method for coal roadway excavation faces based on pre-drainage extraction boreholes is shown. As shown in the figure, this embodiment 1, a gas concentration early warning method for coal roadway excavation faces based on pre-drainage extraction boreholes, includes the following:

[0047] S1. Utilize the high-efficiency extraction tunnel 1 extraction borehole;

[0048] Using a directional drilling rig 10, a cross-layer borehole 3 is constructed in the excavation roadway 1 of the coal seam 7 in the drilling site 2 of the high-extraction roadway 5. The borehole locations are the entire excavation roadway 1 and the roadway 4 to be excavated, including a range of 15m outside the outline of the two roadways 1 and 4 to be excavated. The borehole spacing is 2R, where R is the drilling extraction radius. In this embodiment 1, R is 2.5m.

[0049] A drilling field 2 is arranged every 4 to 6 rows of cross-layer boreholes 3. The spacing between each drilling field 2 is generally no more than 10 m. In this embodiment 1, one drilling field 2 is arranged every 4 rows of cross-layer boreholes 3.

[0050] S2. Install a single-hole gas precision metering instrument 8 and a drilling stress measuring instrument 9;

[0051] Install a single-hole gas precision meter 8 and a drilling stress measuring instrument 9 in all cross-layer boreholes 3 within a drilling range 3 ahead of the current location of the tunneling machine; the single-hole gas precision meter 8 is set in the middle of the cross-layer borehole 3, and the drilling stress measuring instrument 9 is set on the coal seam 7.

[0052] S3. Install the gas concentration analysis module 12, the ground stress analysis module 11, and the gas over-limit early warning module 13;

[0053] The drilling rig 10 is connected to the gas over-limit early warning module 13, which is connected to the ground stress analysis module 11 and the gas concentration analysis module 12 respectively. The ground stress analysis module 11 is connected to each drilling-while-drilling ground stress measuring instrument 9, and the gas concentration analysis module 12 is connected to each single-hole gas precision metering instrument 8. Thus, while extracting gas, the gas single-hole precision metering data and the ground stress drilling-while-drilling measurement data are obtained in real time.

[0054] The single-hole gas precision meter 8 and the drilling stress measurement instrument 9 are data acquisition modules. The data acquisition modules collect borehole gas parameter data (i.e., single-hole precision metering data of gas drainage boreholes) and drilling stress measurement data during the working face tunneling process. The gas concentration analysis module 12 and the ground stress analysis module 11 perform corresponding fitting analysis on the collected single-hole precision metering data of gas drainage boreholes and the drilling stress monitoring data to obtain gas and ground stress early warning indicators. The gas over-limit early warning module 13 provides early warning of gas over-limit accidents during the tunneling process based on the fitting results.

[0055] The data acquisition module is used to collect monitoring data and provide early warning basic data for the other modules. The data acquisition module mainly includes a single-hole gas precision meter 8 and a drilling stress measuring instrument 9, and is connected to the corresponding analysis module through wireless sensors.

[0056] The gas concentration analysis module 12 is mainly used to analyze the changes in gas concentration characteristics in the tunnel in real time, and to predict the gas concentration sequence of the tunnel in the future. It obtains the real-time change curve of ultra-low gas concentration, the prediction curve of gas concentration change, and the maximum value of future gas concentration, and obtains the prediction index of gas concentration. The gas concentration analysis module 12 can use the YZC6 gas drainage pipeline multi-parameter measuring instrument software (2023SR1201469) available on the market.

[0057] The in-situ stress analysis module 11 is mainly used to analyze the changes in in-situ stress in hard and soft rocks. Combining the drilling rig output energy, drill cuttings volume and drill cuttings particle size distribution during the drilling process, it calculates the magnitude of in-situ in-situ stress in soft and hard rocks, obtains the in-situ stress change curve and prediction curve, as well as the maximum value that may occur in the future, and obtains the prediction index of in-situ stress while drilling. The in-situ stress analysis module 11 can use the YZC6 type gas drainage pipeline multi-parameter measuring instrument software (2023SR1201469), or refer to the downhole in-situ stress measurement system provided by Chinese patent CN202322197718.1.

[0058] The gas over-limit early warning module 13 identifies the risk of gas over-limit based on the gas concentration analysis module 12 and the ground stress analysis module 11, and gives an early warning result on the magnitude of the gas over-limit risk.

[0059] S4. Real-time acquisition of gas monitoring data within the coal roadway excavation face (including a 15 m range outside the outline of the two roadways) and gas monitoring data from at least three advanced drilling sites 6; advanced drilling site 6 refers to the drilling site that is ahead of the current tunneling machine; the gas concentration range obtained from the single-hole gas accurate metering data is 0~100%;

[0060] S5. Extract the current gas monitoring value. M t Compared to the current moment T 1 , T 2 Gas monitoring data over a specific time period;

[0061] The time period T 1 represents 15-20 minutes; time period T 2. Determined based on the working face advance speed;

[0062] S6, according to T Gas monitoring data over a time period, and the gas concentration analysis module calculates the following indicators. N t ;

[0063] index N t The average value of gas monitoring data over time period T1 prior to the current moment is calculated as follows:

[0064] ;

[0065] Short-term gas over-limit warning threshold N 0 Take the time before the current moment T 1 Time period indicators N t If the indicator N t Greater than the threshold N 0. Issue a short-term warning for gas exceeding the limit for 10 to 15 minutes. Repeat this step continuously. If two or more short-term warnings for gas exceeding the limit are issued consecutively, immediately implement the gas-electric interlock operation.

[0066] S7, according to T Gas monitoring data over two time periods; gas concentration analysis module calculates indicators. P t ;

[0067] index P t Before the current moment T 2 The average value of gas monitoring data over a time period is calculated as follows:

[0068] ;

[0069] in, y i for T Gas monitoring data of the working face at different times within the 2-period time period; v For the working face advance speed; l The working face advance distance is generally taken as 30~50 m;

[0070] S8, When the indicator N t Greater than the threshold N At 0:00, a short-term warning for excessive gas levels is issued; when the gas monitoring value... M t Greater than the threshold M At 0:00, an emergency warning for excessive gas levels will be issued;

[0071] threshold M 0 takes the time before the current moment. T 2 Average value of gas monitoring data over a period of time P t 200%, that is, an average gas concentration of 25%, threshold. M 0 is set to 50%, threshold M The calculation method for 0 is as follows:

[0072] ;

[0073] like M t Greater than M If the value is 0, an emergency warning for excessive gas levels will be issued, and gas-electric interlocking operations will be immediately implemented.

[0074] S9. As the tunneling face advances, repeat steps S5 to S8 to provide dynamic real-time early warning of excessive gas levels at the working face.

[0075] In this embodiment 1, T Take 15 minutes. T Take 2 days, and calculate... N t =18.8%, P t =20.15%, M t =16.2%, M 0 = 40.3%.

[0076] In-situ stress measurement while drilling early warning includes the following:

[0077] S1. Drill through the coal seam in the high-extraction roadway to obtain real-time ground stress monitoring data Z within the tunnel and the roadway to be excavated (including a 15 m range outside the outline of the two roadways) and at least three preceding drilling sites, and extract the data prior to the current moment. T 1. T Drilling-while-monitoring data of in-situ stress in the coal seam roof strata over two time periods, and collection of drill cuttings; the time periods... T 1 is 15~20 minutes; time period T 2. Determined based on the working face advance speed;

[0078] S2. As the tunnel is advanced, step S2 is repeated continuously.

[0079] according to T 2 In-situ ground stress is calculated using ground stress monitoring data over a specific time period through a ground stress analysis module. α t The aforementioned indicators will be sent to the ground for backup.

[0080] When the geostress monitoring data Z of the rock stratum to be tested is greater than the threshold α 0. Issue an emergency warning for excessive gas levels. Once the warning is triggered, immediately implement the gas-electric interlock operation. α t and α The calculation method for 0 is as follows:

[0081] ;

[0082] in, z i for T 2 Rock strata stress monitoring data from different boreholes within a time period; v For the working face advance speed; l The distance the working face advances.

[0083] In this embodiment 1, the following is calculated: α t =11.1 MPa α 0 = 22.2 MPa.

[0084] During the tunneling process, the extraction boreholes are located in the entire tunneling roadway 1 and the roadway 4 to be excavated (including a 15 m range outside the outline of the two roadways). In this embodiment, the gas over-limit intelligent early warning system is installed in all the cross-layer boreholes within a range of 3 drilling sites ahead of the current tunneling head location. After the tunneling machine advances past the location of the drilling site, the gas over-limit integrated intelligent early warning analysis system can be removed and moved to the drilling site ahead, so that the gas over-limit integrated intelligent early warning analysis system always covers all the cross-layer boreholes within a range of 3 drilling sites ahead of the current tunneling machine location.

[0085] When drilling multiple high-pressure drainage tunnels across different strata to measure in-situ stress, the spacing between boreholes should be sufficiently large to avoid affecting adjacent boreholes. To improve the accuracy of in-situ stress monitoring data, different types of rock strata should be considered. ξ Conduct separate experimental tests and verifications. Example 2

[0086] See Figures 5-7 , Figure 5 A layout diagram of the drilling site for a gas concentration early warning method for coal roadway excavation faces based on pre-drainage drilling boreholes is shown. As shown in the figure, this embodiment 2, a gas concentration early warning method for coal roadway excavation faces based on pre-drainage drilling boreholes, differs from embodiment 1 in that:

[0087] In this embodiment 2, the bottom extraction roadway 14 extraction borehole is used to construct the cross-layer borehole 3 from the drilling site 2 of the bottom extraction roadway 14 to the tunneling roadway 1 arranged in the coal seam 7. The borehole location is the entire tunneling roadway 1 and the roadway 4 to be excavated (including the range of 15 m outside the outline of the two roadways).

[0088] Working principle:

[0089] This invention provides a method for early warning of gas concentration at coal roadway excavation faces based on pre-extraction roadway drainage boreholes. It combines single-hole gas metering data with drilling-while-drilling in-situ stress data to collaboratively predict gas exceedance accidents at coal roadway excavation faces. The method involves constructing cross-layer boreholes from high-extraction roadways or bottom-extraction roadways (gas pre-extraction roadways) towards the coal roadway excavation face, with boreholes deployed within 15 m of both sides of the excavation roadway and at least three drilling sites ahead of the excavation roadway. Real-time acquisition of single-hole gas data and drilling-while-drilling in-situ stress data at the coal roadway excavation face is achieved. The gas exceedance threshold is fitted and analyzed using gas concentration analysis and in-situ stress analysis modules and compared with real-time monitoring data. Finally, a gas exceedance early warning module is used to collaboratively predict gas exceedance accidents at the coal roadway excavation face.

[0090] The above are merely specific application examples of the present invention and do not constitute any limitation on the scope of protection of the present invention. All technical solutions formed by equivalent transformations or substitutions fall within the scope of protection of the present invention.

Claims

1. A method for early warning of gas concentration in a mine longwall face based on pre-drainage roadway drainage boreholes, characterized in that, Includes the following: S1. Utilize pre-drainage roadway extraction boreholes; Drilling rigs are used in drilling sites of high-level or low-level drainage roadways to drill through-seam boreholes into the longwall face located in the coal seam. The borehole locations are the entire longwall face, including the area 15m outside the roadway outline of the two longwall face roadways on the longwall face. A drilling site is set up every 4 to 6 rows of through-seam boreholes, and the distance between each drilling site does not exceed 10m. S2. Install a single-hole gas precision meter and a drilling stress measuring instrument; Install single-hole gas precision metering instruments and drilling stress measuring instruments in all cross-layer boreholes within a drilling area of ​​three drilling sites ahead of the current location of the coal mining machine. S3. Install the gas concentration analysis module, the ground stress analysis module, and the gas over-limit early warning module; The drilling rig is connected to a gas over-limit early warning module, which is connected to a ground stress analysis module and a gas concentration analysis module. The ground stress analysis module is connected to each drilling stress measuring instrument, and the gas concentration analysis module is connected to each single-hole gas precision metering instrument. Thus, while extracting gas, the single-hole gas precision metering data and the ground stress drilling measurement data are obtained in real time. S4. Real-time acquisition of gas monitoring data from at least three drilling sites of the advanced coal mining machine within the entire longwall face, including a 15 m range outside the outline of the two roadways. S5. Extract the current gas monitoring value. M t Compared to the current moment T 1 , T 2 Gas monitoring data over a specific time period; S6, according to T Gas monitoring data for a given time period; gas concentration analysis module calculates indicators. N t ; index N t The average value of gas monitoring data for time period T1 prior to the current moment, the indicator. N t The calculation method is as follows: ； Short-term gas over-limit warning threshold N 0 Take the time before the current moment T 1 Time period indicators N t ; S7, according to T Gas monitoring data over two time periods; gas concentration analysis module calculates indicators. P t ; index P t Before the current moment T 2 The average value of gas monitoring data over a period of time, indicators P t The calculation method is as follows: ； in, y i for T Gas monitoring data of the working face at different times within the 2-period time period; v For the working face advance speed; l The distance the working face advances; S8, When the indicator N t Greater than the threshold N At 0:00, a short-term warning for excessive gas levels is issued; when the gas monitoring value... M t Greater than the threshold M At 0:00, an emergency warning for excessive gas levels will be issued; threshold M 0 takes the time before the current moment. T 2 Average value of gas monitoring data over a period of time P t 200% of, that is: ； If the current gas monitoring value M t Greater than M If the gas level is 0, an emergency warning for exceeding the gas limit will be issued, and the gas-electric interlock operation will be immediately implemented to cut off the power supply to the coal mining machine and stop the coal mining machine from working. S9. As the working face advances, repeat steps S5 to S8 to provide dynamic real-time early warning of excessive methane concentration at the working face.

2. The method for early warning of gas concentration in a mine longwall face based on pre-drainage boreholes as described in claim 1, characterized in that: In step S1, the spacing between the boreholes in the cross-layer drilling is 2R, where R is the drilling extraction radius.

3. The method for early warning of gas concentration in a mine longwall face based on pre-drainage boreholes as described in claim 1, characterized in that: In step S2, the single-hole gas precision meter is set in the middle of the cross-layer borehole, and the drilling stress measuring instrument is set on the mining face.

4. The method for early warning of gas concentration in a mine longwall face based on pre-drainage boreholes as described in claim 1, characterized in that: Time period in step S5 T 1 represents 10-15 minutes; time period T 2. Determined based on the working face advance speed.

5. A method for early warning of gas concentration in a mine longwall face based on pre-drainage boreholes, as described in claim 1, characterized in that: This step is repeated continuously in step S6, if the indicator N t Greater than the threshold N 0, issue a short-term warning for gas exceeding the limit for 10-15 minutes; If there are two or more consecutive short-term warnings for exceeding the gas limit, immediately implement the gas-electric interlock operation to cut off the power supply to the coal mining machine and stop the coal mining machine from working.

6. The method for early warning of gas concentration in a mine longwall face based on pre-drainage boreholes according to claim 1, characterized in that: The gas concentration range obtained from the precise metering data of a single gas well is 0~100%.

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