A mine stoping working face gas concentration early warning method based on pre-drainage and extraction of a drilling hole

Abstract

The application relates to a kind of mine stoping working face gas concentration early warning methods based on pre-extraction of extraction drilling, it includes data acquisition module, gas concentration analysis module and gas overrun early warning module, data acquisition module collects the accurate measurement data of single hole of gas extraction drilling in the process of working face stoping;Gas concentration analysis module carries out corresponding fitting analysis to the accurate measurement data of single hole of gas extraction drilling and ground stress monitoring data collected, obtains gas concentration early warning index;Gas overrun early warning module cooperates with gas overrun accident in the process of stoping according to the fitting result and early warning.The application realizes the real-time early warning of gas overrun in stoping roadway, effectively guarantees the production safety of mine.

Description

Technical Field

[0001] This invention relates to the field of gas disaster prediction technology, and in particular to a method for early warning of gas concentration in mine longwall faces based on pre-drainage roadway drilling. Background Technology

[0002] Coal energy remains a major component of my country's energy structure. Due to my country's unique geological environment, coal mining is mostly conducted underground, with most mines containing methane gas. More than half of these mines have significant methane levels or are prone to gas outbursts. Furthermore, the high spatial density of coal, low permeability between coal seams, and difficulty in pre-mining drainage make gas disasters highly likely during mining. Excessive methane concentration in coal mines refers to the abnormal phenomenon where the methane concentration exceeds the prescribed safety limits in the underground working environment. Excessive methane concentration can easily lead to catastrophic accidents such as coal and gas outbursts and gas explosions. Therefore, preventing underground methane accumulation or exceeding limits is a crucial step in preventing coal and gas outbursts and gas explosions, and also a necessary means to provide workers with a safe working environment. To prevent such accidents, coal mines are generally equipped with safety monitoring systems, enabling online monitoring of methane concentration in key underground areas and automatic alarms when methane levels exceed limits.

[0003] Prevention of excessive gas concentrations is a crucial aspect of coal mine gas disaster prevention. However, gas disasters are influenced by numerous factors, have complex causes, and are prone to cascading disasters. Existing safety monitoring systems suffer from problems such as limited measurement parameters, inaccurate measurements, and untimely responses. Therefore, there is an urgent need for a method to intelligently predict excessive gas concentrations at the working face. Summary of the Invention

[0004] The purpose of this invention is to overcome the above-mentioned shortcomings and provide a method for early warning of gas concentration in coal mine longwall faces based on pre-drainage drilling boreholes. Through intelligent analysis of high-precision low gas flow monitoring data from the drilling boreholes, a non-contact, continuous, and intelligent early warning system for the risk of excessive gas levels in coal mine longwall faces can be achieved, which is beneficial for the proactive prevention and control of coal mine gas accidents.

[0005] The objective of this invention is achieved as follows:

[0006] A method for early warning of gas concentration in a mine longwall face based on pre-drainage roadway drainage boreholes includes the following:

[0007] S1. Utilize pre-drainage roadway extraction boreholes;

[0008] Drilling rigs are used in the drilling sites of high-level or low-level extraction 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 15 m outside the roadway outline of the two longwall face roadways on the longwall face.

[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 ​​three drilling sites ahead of the current location of the coal mining 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 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.

[0013] 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.

[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 for a given time period; gas concentration analysis module calculates 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] index Pt The calculation method is as follows:

[0021] index P t Before the current moment T 2 The average value of gas monitoring data over a time period is calculated as follows:

[0022] ;

[0023] 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;

[0024] 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;

[0025] 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.

[0026] Furthermore, in step S1, the spacing between the boreholes in the cross-layer drilling is 2R, where R is the drilling extraction radius.

[0027] 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.

[0028] Furthermore, the single-hole gas precision metering in step S2 is set in the middle of the cross-layer borehole, and the drilling stress measuring instrument is set on the mining face.

[0029] Furthermore, the time period in step S5 T 1 represents 10-15 minutes; time period T 2. Determined based on the working face advance speed.

[0030] Furthermore, this step is repeated continuously in step S6, if the index N t Greater than N 0. Issue a short-term warning for gas exceeding the limit for 10 to 15 minutes. If there are two or more consecutive short-term warnings for gas exceeding the limit, immediately implement a gas-electric interlock operation to cut off the power supply to the coal mining machine and stop the coal mining machine from working.

[0031] 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:

[0032] ;

[0033] 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 a gas-electric interlock operation will be immediately implemented to cut off the power supply to the coal mining machine, causing the machine to stop working.

[0034] Furthermore, the gas concentration range obtained from the precise metering data of a single gas well is 0~100%.

[0035] Compared with the prior art, the beneficial effects of the present invention are:

[0036] This invention enables in-depth analysis of mine gas monitoring data and ground stress monitoring data. By real-time monitoring and analysis of gas parameters at least three drilling sites of the advanced coal mining machine within the longwall face (including a 15 m range outside the outline of the two roadways), it achieves precise single-hole measurement of gas drainage boreholes and real-time early warning of excessive gas concentration in longwall roadways, effectively ensuring the production safety of the mine. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the layout inside the drilling site according to Embodiment 1 of the present invention.

[0038] Figure 2 This is a schematic diagram of the perforation plan of Embodiment 1 of the present invention.

[0039] Figure 3 This is a front view of the perforation layout in Embodiment 1 of the present invention.

[0040] Figure 4 This is a side view of the perforation pattern in Embodiment 1 of the present invention.

[0041] Figure 5 This is a schematic diagram of the layout inside the drilling site according to Embodiment 2 of the present invention.

[0042] Figure 6 This is a schematic diagram of the perforation plan of Embodiment 2 of the present invention.

[0043] Figure 7 This is a front view of the perforation layout in Embodiment 2 of the present invention.

[0044] Figure 8This is a side view of the perforation pattern in Embodiment 2 of the present invention.

[0045] in:

[0046] 1. High-speed drainage roadway; 2. Drilling site; 3. Coal seam; 4. Longwall face; 5. Cross-layer borehole; 6. Longwall face roadway; 7. Single-hole gas precision meter; 8. Drilling stress measuring instrument; 9. Drilling rig; 10. Stress analysis module; 11. Gas concentration analysis module; 12. Gas over-limit early warning module; 13. Bottom drainage roadway. Detailed Implementation

[0047] 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.

[0048] Example 1:

[0049] See Figures 1-4 , Figure 1 A schematic diagram of the drilling site layout for a gas concentration early warning method for a mine longwall face based on a pre-drainage roadway extraction borehole is shown. As shown in the figure, this embodiment 1, a gas concentration early warning method for a mine longwall face based on a pre-drainage roadway extraction borehole, includes the following:

[0050] S1. Utilize the high-efficiency extraction tunnel 1 extraction borehole;

[0051] From the drilling site 2 of the high-extraction roadway 1, drilling rig 9 is used to construct cross-layer boreholes 5 towards the longwall face 4 arranged in the coal seam 3. The borehole locations are the entire longwall face 4, including the area 15 m outside the roadway outline of the two longwall face roadways 6 on the longwall face 4. The borehole spacing is 2R, where R is the drilling extraction radius. In this embodiment 1, R is 2m.

[0052] A drilling field 2 is arranged every 4 to 6 rows of cross-layer boreholes 5. 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 5.

[0053] S2. Install a single-hole gas precision meter 7 and a drilling stress measuring instrument 8;

[0054] Install a single-hole gas precision meter 7 and a drilling stress measuring instrument 8 in all cross-layer boreholes 5 within a drilling range 3 drilling sites ahead of the current location of the coal mining machine; the single-hole gas precision meter 7 is set in the middle of the cross-layer borehole 5, and the drilling stress measuring instrument 8 is set on the longwall face 4.

[0055] S3. Install the gas concentration analysis module 11, the ground stress analysis module 10, and the gas over-limit early warning module 12;

[0056] The drilling rig 9 is connected to the gas over-limit early warning module 12, which is connected to the ground stress analysis module 10 and the gas concentration analysis module 11 respectively. The ground stress analysis module 10 is connected to each drilling-while-drilling ground stress measuring instrument 8, and the gas concentration analysis module 11 is connected to each single-hole gas precision metering instrument 7. 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.

[0057] The single-hole gas precision meter 7 and the drilling stress measurement instrument 8 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 mining process. The gas concentration analysis module 11 and the drilling stress analysis module 10 perform corresponding fitting analysis on the collected single-hole precision metering data of gas drainage boreholes and drilling stress monitoring data to obtain gas and drilling stress early warning indicators. The gas over-limit early warning module 12 provides early warning of gas over-limit accidents during the mining process based on the fitting results.

[0058] The data acquisition module is used to collect monitoring data, provide basic data for early warning to other modules, and connect to the corresponding analysis module through wireless sensors;

[0059] The gas concentration analysis module 11 is mainly used to analyze the changes in gas concentration characteristics of the longwall face in real time, and to predict the gas concentration sequence of the longwall face in the future, so as to obtain 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 obtain the prediction index of gas concentration; the gas concentration analysis module 11 can use the YZC6 type gas drainage pipeline multi-parameter measuring instrument software (2023SR1201469) on the market.

[0060] The geostress analysis module 10 is mainly used to analyze the changes in geostress 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 geostress in soft and hard rocks, obtains the in-situ geostress change curve and prediction curve, as well as the maximum value that may occur in the future geostress, and obtains the prediction index of geostress while drilling. The geostress analysis module 10 can use the YZC6 type gas drainage pipeline multi-parameter measuring instrument software (2023SR1201469), or refer to the downhole geostress measurement system provided by Chinese patent CN202322197718.1.

[0061] The gas over-limit early warning module 12 identifies the risk of gas over-limit based on the gas concentration analysis module 11 and the ground stress analysis module 10, and gives an early warning result on the magnitude of the gas over-limit risk.

[0062] S4. Real-time acquisition of gas monitoring data from at least three drilling sites of the advanced coal mining machine within the longwall face (including a 15 m radius outside the outline of the two roadways); the gas concentration range of the single-hole gas accurate metering data is 0~100%;

[0063] 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;

[0064] The time period T 1 represents 10-15 minutes; time period T 2. Determined based on the working face advance speed;

[0065] S6, according to T Gas monitoring data for a given time period; gas concentration analysis module calculates indicators. N t ;

[0066] index N t The average value of gas monitoring data over time period T1 prior to the current moment is calculated as follows:

[0067] ;

[0068] 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, cut off the power supply to the coal mining machine, and stop the coal mining machine from working.

[0069] S7, according to T Gas monitoring data over two time periods; gas concentration analysis module calculates indicators. P t ;

[0070] index P t Before the current moment T 2The average value of gas monitoring data over a time period is calculated as follows:

[0071] ;

[0072] 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 15~30 m;

[0073] 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;

[0074] 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:

[0075] ;

[0076] like 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.

[0077] 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.

[0078] In this embodiment 1, T Take 15 minutes. T Take 2 days and calculate. N t =17.8%, P t =19.55%, M t =15.1%, M 0 = 39.1%.

[0079] In-situ stress measurement while drilling early warning includes the following:

[0080] S1. Drill through the coal seam in the high-extraction roadway to obtain real-time ground stress monitoring data Z from at least three drilling sites of the advanced coal mining machine within the longwall face (including a 15m range outside the outline of the two roadways), and extract the data before the current time. 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 represents 10-15 minutes; time period T 2. Determined based on the working face advance speed;

[0081] S2. As the longwall face advances, repeat step S2 continuously.

[0082] 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.

[0083] When the in-situ geostress monitoring data Z of the rock stratum under test is greater than the threshold α 0. Issue an emergency warning for excessive gas levels. Once the warning is triggered, immediately implement a gas-electric interlock operation to cut off the power supply to the coal mining machine and stop its operation. α t and α The calculation method for 0 is as follows:

[0084] ;

[0085] in, z i for T 2 In-situ stress monitoring data of rock strata from different boreholes within a time period; v For the working face advance speed; l The distance the working face advances.

[0086] In this embodiment 1, α t =12.1 MPa α 0 = 24.2 MPa.

[0087] During the longwall mining process, the location of the extraction boreholes is the entire longwall mining face (including a 15 m range outside the outline of the two roadways). In this embodiment, the intelligent early warning system for excessive gas levels is installed at all cross-layer boreholes within a range of three drilling sites ahead of the current location of the coal mining machine. After the coal mining machine advances past the location of the drilling site, the intelligent early warning system for excessive gas levels in this embodiment can be removed and moved to a drilling site behind it, so that the intelligent early warning system for excessive gas levels always covers all cross-layer boreholes within a range of three drilling sites ahead of the current location of the coal mining machine.

[0088] Example 2:

[0089] See Figures 5-8 , Figure 5 A layout diagram of the drilling site for a gas concentration early warning method for a mine longwall face based on a pre-drainage roadway extraction borehole is shown. As shown in the figure, this embodiment 2, a gas concentration early warning method for a mine longwall face based on a pre-drainage roadway extraction borehole, differs from embodiment 1 in that:

[0090] In this embodiment 2, the drilling rig 9 is used to drill through the coal seam 3 from the drilling site 2 of the bottom drainage roadway 13 to the longwall face 4 of the coal seam 3.

[0091] Working principle:

[0092] This invention provides a method for early warning of gas concentration in a mine longwall face based on pre-drainage roadway drainage boreholes. It uses single-hole gas metering data to collaboratively predict gas exceedance accidents at the longwall face. A cross-layer borehole is constructed from a high-level drainage roadway or a bottom-level drainage roadway (gas pre-drainage roadway) towards the longwall face, and a single-hole precise gas meter is installed. Real-time gas data from the single-hole borehole at the longwall face is acquired, and the gas concentration analysis module is used to fit and analyze the gas exceedance threshold, comparing it with real-time monitoring data. Then, a gas exceedance early warning module is used to collaboratively predict gas concentration exceedance accidents at the mine longwall face.

[0093] 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 over a time period, and the gas concentration analysis module calculates the following 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%.

Images