A method for predicting coal seam stability based on coal seam drilling status

Abstract

The present invention relates to the field of coal seam stability prediction, and specifically discloses a method for predicting coal seam stability based on coal seam drilling status. The present invention monitors the drilling speed and drilling depth during coal seam drilling, identifies the abnormal time point of drilling speed and the corresponding relative deviation of drilling speed, and evaluates the coal seam stability guided by drilling speed; monitors the torque and drilling depth during coal seam drilling, draws a curve of torque variation with drilling depth, and evaluates the coal seam stability guided by drilling torque; monitors the vibration amplitude and vibration frequency of the drill bit during coal seam drilling, draws a curve of vibration amplitude and vibration frequency variation with time, and evaluates the coal seam stability guided by drilling vibration; and comprehensively evaluates the coal seam stability from multiple indicators such as drilling speed, drilling torque and drilling vibration, thereby improving the reliability of the evaluation result, ensuring the safety of coal mine mining, and providing safety guidance and decision-making basis for subsequent mining activities.

Description

Technical Field

[0001] The invention relates to the field of coal seam stability prediction, and in particular to a method for predicting coal seam stability based on coal seam drilling status. Background Art

[0002] As the depth of coal mining increases, the ground stress also increases, which is easy to cause disasters such as gas outburst and coal and gas outburst. When conducting coal seam drilling operations, predicting coal seam stability is a very important link and an important topic in mining engineering and geological engineering. This is not only related to the safety and efficiency of mining, but also directly affects environmental protection and the rational use of resources. Therefore, predicting coal seam stability is extremely important for ensuring coal mine safety production, improving resource utilization and protecting the environment.

[0003] However, the existing methods for predicting coal seam stability still have some limitations and shortcomings in practical applications.

[0004] For example, the existing Chinese patent with publication number CN106032753A discloses a system and method for predicting coal seam stability based on coal seam drilling status. The invention aims to quantitatively describe the coal seam drilling status and provide a reference for predicting coal seam stability. During the drilling operation of the drilling rig, the drilling rig drilling status test system monitors the actual output power of the drilling rig in real time. When the actual output power remains stable and is not greater than the rated power of the drilling rig, it can be considered that the drilling process is normal and the drilling coal seam has good stability; when the actual output power fluctuates greatly or exceeds the rated power of the drilling rig for a long time, it is considered that the drilling is abnormal and the drilling coal seam has poor stability, and the alarm system is activated to remind the operating workers and engineering and technical personnel to take corresponding anti-outburst measures to prevent the occurrence of coal and gas outburst accidents.

[0005] However, the above patent only judges whether the coal seam is stable based on the output power of the drilling rig during operation. The analysis indicators are single and not multifaceted enough, which makes the coal seam stability assessment system incomplete, thereby reducing the reliability and rigor of the coal seam stability assessment results, and is prone to misjudgment and wrong judgment. Summary of the invention

[0006] In response to the above problems, the present invention proposes a method for predicting coal seam stability based on coal seam drilling status. The specific technical scheme is as follows: A method for predicting coal seam stability based on coal seam drilling status, comprising the following steps: Step 1, coal seam drilling speed monitoring and analysis: obtain the drilling speed and drilling depth at each monitoring time point during the coal seam drilling process, identify the abnormal drilling speed time points during the coal seam drilling process and analyze the relative deviation of the drilling speed at each abnormal drilling speed time point, and further evaluate the drilling speed-guided coal seam stability coefficient.

[0007] Step 2: Coal seam drilling torque monitoring and analysis: Obtain the torque and drilling depth at each monitoring time point during coal seam drilling, draw a curve of torque variation with drilling depth during coal seam drilling, and compare it with the corresponding sample curves of torque variation with drilling depth when the coal seam is unstable, to further evaluate the coal seam stability coefficient guided by drilling torque.

[0008] Step 3: Coal seam drilling vibration monitoring and analysis: obtain the vibration amplitude and vibration frequency of the drill bit at each monitoring time point during the coal seam drilling process, draw the curve of the vibration amplitude and vibration frequency changing with time during the coal seam drilling process, and further evaluate the coal seam stability coefficient guided by drilling vibration.

[0009] Step 4. Comprehensive evaluation of coal seam stability: Analyze the comprehensive evaluation index of coal seam stability based on the drilling speed-guided coal seam stability coefficient, the drilling torque-guided coal seam stability coefficient, and the drilling vibration-guided coal seam stability coefficient.

[0010] Step 5. Coal seam drilling risk warning feedback: Based on the comprehensive assessment index of coal seam stability, determine whether there is a safety risk in continuing to drill into the coal seam. If there is a safety risk, a warning will be issued and feedback will be given to the coal seam drilling construction supervision department.

[0011] On the basis of the above-mentioned embodiment, the specific analysis process of step one includes: setting the time interval for data collection, and further setting each monitoring time point during the coal seam drilling process according to the principle of equal time intervals.

[0012] The drilling speed at each monitoring time point during the coal seam drilling process is obtained through a drilling speed monitoring instrument, and the drilling depth at each monitoring time point during the coal seam drilling process is obtained through a depth recorder.

[0013] If the difference in drilling speed between a certain monitoring time point and its adjacent previous monitoring time point during coal seam drilling is greater than a preset drilling speed difference threshold, then the monitoring time point during coal seam drilling is recorded as an abnormal drilling speed time point, and statistics are collected on each abnormal drilling speed time point during coal seam drilling.

[0014] Based on the above embodiment, the specific analysis process of step 1 also includes: obtaining the difference in drilling speed between each abnormal drilling speed time point and its adjacent previous monitoring time point during coal seam drilling, and recording it as , Indicates The number of the time point when the turning speed is abnormal, , and obtain the difference between the drilling pressure and drill bit speed at each abnormal drilling speed time point and its adjacent previous monitoring time point during coal seam drilling, and record them as .

[0015] By analyzing the formula Get the relative deviation of drilling speed at each abnormal drilling speed time point ,in Indicates the preset compensation amount of drilling speed difference. They respectively represent the thresholds of the preset drilling pressure difference and drill bit speed difference.

[0016] On the basis of the above embodiment, the specific analysis process of step 1 further includes: recording each abnormal drilling speed time point during coal seam drilling as the time point corresponding to each change in coal seam hardness during coal seam drilling, and further obtaining the average frequency of coal seam hardness change during coal seam drilling, which is recorded as .

[0017] According to the drilling depth at each monitoring time point during the coal seam drilling process, the drilling depth corresponding to each change in coal seam hardness during the coal seam drilling process is screened and recorded as , Indicates the hardness of the coal seam during coal seam drilling. The number of the change. .

[0018] Substitute the relative deviation of the drilling speed at each abnormal time point during the coal seam drilling process into the relationship function between the relative deviation of the drilling speed and the change in coal seam hardness stored in the database to obtain the change in hardness corresponding to each change in coal seam hardness during the coal seam drilling process, which is recorded as .

[0019] By analyzing the formula

[0020] Obtain the drilling speed-guided coal seam stability coefficient ,in The correction factor for the coal seam stability factor for the preset drilling speed guidance, represents a natural constant, Respectively represent the weight factors of the preset frequency and amount of change of coal seam hardness, , They represent the preset thresholds of the change frequency and change amount of the coal seam hardness, Indicates the impact factor corresponding to the preset unit drilling depth.

[0021] On the basis of the above-mentioned embodiment, the specific analysis process of step 2 includes: obtaining the torque at each monitoring time point during the coal seam drilling process through a torque monitor.

[0022] A coordinate system is established with drilling depth as the horizontal axis and torque as the vertical axis. According to the torque and drilling depth at each monitoring time point during coal seam drilling, the corresponding data points are marked in the coordinate system. The mathematical model establishment method is used to draw a curve of the change of torque with drilling depth during coal seam drilling.

[0023] On the basis of the above embodiment, the specific analysis process of step 2 also includes: extracting the sample curves of torque variation with drilling depth corresponding to the instability of the coal seam stored in the database, recording them as sample curves of abnormal torque variation with drilling depth, comparing the curve of torque variation with drilling depth during coal seam drilling with the sample curves of abnormal torque variation with drilling depth, obtaining the length of the curve segment in the curve of torque variation with drilling depth during coal seam drilling, whose shape similarity with the sample curves of abnormal torque variation with drilling depth is greater than the set similarity threshold, recording it as the length of the curve segment in the curve of torque variation with drilling depth during coal seam drilling that matches the sample curves of abnormal torque variation with drilling depth, and expressing it as , Indicates The number of the sample curve of abnormal torque changing with drilling depth, .

[0024] By analyzing the formula Obtain the coal seam stability coefficient of drilling torque guidance ,in The correction factor for the seam stability factor of the preset drilling torque steering, Indicates the preset The influence weight of the sample curve of abnormal torque changing with drilling depth is , It represents the length of the curve of torque changing with drilling depth during coal seam drilling.

[0025] On the basis of the above embodiment, the specific analysis process of step three includes: obtaining the vibration amplitude and vibration frequency of the drill bit at each monitoring time point during the coal seam drilling process through a vibration monitor.

[0026] A coordinate system is established with the monitoring time point as the horizontal axis and the vibration amplitude as the vertical axis. According to the vibration amplitude of the drill bit at each monitoring time point during the coal seam drilling process, the corresponding data points are marked in the coordinate system. The mathematical model establishment method is used to draw a curve of the change of vibration amplitude over time during the coal seam drilling process.

[0027] Similarly, according to the method for obtaining the curve of the vibration amplitude changing with time during the coal seam drilling process, the curve of the vibration frequency changing with time during the coal seam drilling process is obtained.

[0028] The peak points of the curve of the vibration amplitude changing with time during coal seam drilling are obtained, and the peak deviation of each peak point is obtained. If the peak deviation of a peak point is greater than the preset peak deviation threshold, the peak point is recorded as a vibration amplitude abnormal point, and the peak deviation of the peak point is recorded as the relative deviation of the vibration amplitude. The relative deviation of the vibration amplitude of each vibration amplitude abnormal point in the curve of the vibration amplitude changing with time during coal seam drilling is counted and recorded as , Indicates The number of the abnormal vibration amplitude point, .

[0029] By analyzing the formula Obtain the first coefficient of coal seam stability under drilling vibration guidance ,in The correction factor of the first coefficient of coal seam stability for the preset drilling vibration guidance, Indicates the preset threshold value of the relative deviation of the vibration amplitude.

[0030] On the basis of the above embodiment, the specific analysis process of step three also includes: according to the change curve of vibration frequency over time during coal seam drilling, the number of fluctuations of vibration frequency during coal seam drilling, the average fluctuation amount and the disorder degree of the change curve of vibration frequency over time are obtained, which are recorded as .

[0031] By analyzing the formula The second coefficient of coal seam stability under drilling vibration guidance is obtained ,in The correction factor of the second coefficient of coal seam stability for the preset drilling vibration guidance, They represent the preset vibration frequency fluctuation times, vibration frequency fluctuation amount, and the threshold value of the degree of disorder of the vibration frequency change curve over time. They respectively represent the preset number of vibration frequency fluctuations, the vibration frequency fluctuation amount, and the weights of the degree of disorder of the vibration frequency variation curve over time. .

[0032] The weighted average of the first coefficient of coal seam stability guided by drilling vibration and the second coefficient of coal seam stability guided by drilling vibration is calculated to obtain the coal seam stability coefficient guided by drilling vibration, which is expressed as .

[0033] Compared with the prior art, the method for predicting coal seam stability based on coal seam drilling status described in the present invention has the following beneficial effects: 1. The present invention can timely discover changes in coal seam stability by real-time monitoring of the drilling speed, an important indicator for coal seam stability assessment. If the drilling speed fluctuates abnormally, it may indicate that there are unstable factors in the coal seam ahead, such as thinning of the coal seam, broken zones, geological structures, etc., thereby providing early warning for engineering personnel, taking corresponding safety measures, and avoiding potential accident risks.

[0034] 2. The present invention monitors the drilling torque, an important indicator for evaluating coal seam stability, in real time. If the drilling torque suddenly increases, it may mean that the coal seam ahead has encountered hard rocks or geological structures, which may pose a potential danger. This can provide early warning to engineering personnel, so that they can take corresponding safety measures to avoid accidents.

[0035] 3. The present invention can timely detect changes in coal seam stability by real-time monitoring of drilling vibration amplitude and vibration frequency, which are important indicators for coal seam stability assessment. When the vibration amplitude suddenly increases or the frequency fluctuates abnormally, it may indicate that there are unstable factors in the coal seam ahead, such as broken zones, faults, etc., thereby providing timely early warning information for engineering personnel to take corresponding safety measures to avoid accidents. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for describing the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0037] Figure 1 It is a schematic diagram of the method flow of the present invention.

[0038] Figure 2 Schematic diagram of the analysis process of step one of the present invention.

[0039] Figure 3 It is a block diagram of the composition of the present invention. DETAILED DESCRIPTION

[0040] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] See also Figure 1 and Figure 3 As shown, the present invention provides a method for predicting coal seam stability based on coal seam drilling status, comprising the following steps: Step 1, coal seam drilling speed monitoring and analysis: obtaining the drilling speed and drilling depth at each monitoring time point during the coal seam drilling process, identifying each abnormal drilling speed time point during the coal seam drilling process and analyzing the relative deviation of the drilling speed at each abnormal drilling speed time point, and further evaluating the drilling speed-guided coal seam stability coefficient.

[0042] As a preferred option, see Figure 2 As shown, the specific analysis process of step one includes: setting the time interval for data collection, and further setting each monitoring time point during the coal seam drilling process according to the principle of equal time intervals.

[0043] It should be noted that when setting the time interval for data collection, you can record once every minute or every ten minutes.

[0044] The drilling speed at each monitoring time point during the coal seam drilling process is obtained through a drilling speed monitoring instrument, and the drilling depth at each monitoring time point during the coal seam drilling process is obtained through a depth recorder.

[0045] It should be noted that the drilling speed monitoring instrument and depth recorder are installed on the drilling rig.

[0046] It should be noted that the drilling speed monitoring instrument has the function of data recording and transmission for subsequent analysis.

[0047] In another specific embodiment, the drilling depth within the time interval between the monitoring time point and its previous adjacent monitoring time point is obtained, and the depth is divided by the interval between the monitoring time point and its previous adjacent monitoring time point to obtain the drilling speed at the monitoring time point during coal seam drilling.

[0048] In another specific embodiment, the drilling depth at each monitoring time point during the coal seam drilling process is obtained by using a measuring rope, an electronic rangefinder, or the like.

[0049] It should be noted that the drill bit maintains stability and verticality during coal seam drilling.

[0050] If the difference in drilling speed between a certain monitoring time point and its adjacent previous monitoring time point during coal seam drilling is greater than a preset drilling speed difference threshold, then the monitoring time point during coal seam drilling is recorded as an abnormal drilling speed time point, and statistics are collected on each abnormal drilling speed time point during coal seam drilling.

[0051] It should be noted that the identification of abnormal drilling speed time points during the coal seam drilling process starts from the second monitoring time point during the coal seam drilling process.

[0052] It should be noted that the difference in drilling speed refers to the absolute value of the difference in drilling speed.

[0053] As a preferred solution, the specific analysis process of step 1 further includes: obtaining the difference in drilling speed between each abnormal drilling speed time point and its adjacent previous monitoring time point during coal seam drilling, and recording it as , Indicates The number of the time point when the turning speed is abnormal, , and obtain the difference between the drilling pressure and drill bit speed at each abnormal drilling speed time point and its adjacent previous monitoring time point during coal seam drilling, and record them as .

[0054] By analyzing the formula Get the relative deviation of drilling speed at each abnormal drilling speed time point ,in Indicates the preset compensation amount of drilling speed difference. They respectively represent the thresholds of the preset drilling pressure difference and drill bit speed difference.

[0055] As a preferred solution, the specific analysis process of step 1 further includes: recording each abnormal drilling speed time point during the coal seam drilling process as the time point corresponding to each change in coal seam hardness during the coal seam drilling process, and further obtaining the average frequency of coal seam hardness change during the coal seam drilling process, which is recorded as .

[0056] It should be noted that the faster the drilling speed, the lower the hardness of the coal seam; the slower the drilling speed, the higher the hardness of the coal seam. According to the change of drilling speed, the change of coal seam hardness can be preliminarily judged. If the drilling speed suddenly increases within a certain depth range, it may indicate that the hardness of the coal seam in this area decreases.

[0057] It should be noted that the average frequency of changes in coal seam hardness during coal seam drilling is obtained by the following method: obtain the interval between each change in coal seam hardness and the previous adjacent change during coal seam drilling, record it as the interval between each change in coal seam hardness during coal seam drilling, and calculate the average value to obtain the average frequency of changes in coal seam hardness during coal seam drilling.

[0058] According to the drilling depth at each monitoring time point during the coal seam drilling process, the drilling depth corresponding to each change in coal seam hardness during the coal seam drilling process is screened and recorded as , Indicates the hardness of the coal seam during coal seam drilling. The number of the change. .

[0059] Substitute the relative deviation of the drilling speed at each abnormal time point during the coal seam drilling process into the relationship function between the relative deviation of the drilling speed and the change in coal seam hardness stored in the database to obtain the change in hardness corresponding to each change in coal seam hardness during the coal seam drilling process, which is recorded as .

[0060] It should be noted that the relationship function between the relative deviation of the drilling speed and the change in coal seam hardness stored in the database is obtained based on the experience of historical coal seam drilling operations and geological exploration data.

[0061] By analyzing the formula

[0062] Obtain the drilling speed-guided coal seam stability coefficient ,in The correction factor for the coal seam stability factor for the preset drilling speed guidance, represents a natural constant, Respectively represent the weight factors of the preset frequency and amount of change of coal seam hardness, , They represent the preset thresholds of the change frequency and change amount of the coal seam hardness, Indicates the impact factor corresponding to the preset unit drilling depth.

[0063] It should be noted that if the hardness of the coal seam changes greatly and there are frequent abnormal drilling situations, it may indicate that the coal seam structure is unstable and there are geological structures such as faults and fracture zones. On the contrary, if the drilling speed is relatively stable and the hardness of the coal seam changes little, it means that the coal seam structure is relatively stable.

[0064] It should be noted that the hardness change of the coal seam can be judged by monitoring the drilling speed of the drill bit during the coal seam drilling process, and then the stability of the coal seam structure can be inferred.

[0065] In this embodiment, the present invention can timely discover changes in coal seam stability by real-time monitoring of the drilling speed, an important indicator for coal seam stability assessment. If the drilling speed fluctuates abnormally, it may indicate that there are unstable factors in the coal seam ahead, such as thinning of the coal seam, broken zones, geological structures, etc., thereby providing early warning for engineering personnel, taking corresponding safety measures, and avoiding potential accident risks.

[0066] Step 2: Coal seam drilling torque monitoring and analysis: Obtain the torque and drilling depth at each monitoring time point during coal seam drilling, draw a curve of torque variation with drilling depth during coal seam drilling, and compare it with the corresponding sample curves of torque variation with drilling depth when the coal seam is unstable, to further evaluate the coal seam stability coefficient guided by drilling torque.

[0067] As a preferred solution, the specific analysis process of step 2 includes: obtaining the torque at each monitoring time point during the coal seam drilling process through a torque monitor.

[0068] It should be noted that the torque monitor has high precision, real-time display and data recording functions, and can accurately measure the torque value during coal seam drilling. The torque monitor can be installed on the transmission system of the drilling rig to ensure accurate measurement of drilling torque.

[0069] A coordinate system is established with drilling depth as the horizontal axis and torque as the vertical axis. According to the torque and drilling depth at each monitoring time point during coal seam drilling, the corresponding data points are marked in the coordinate system. The mathematical model establishment method is used to draw a curve of the change of torque with drilling depth during coal seam drilling.

[0070] As a preferred solution, the specific analysis process of step 2 also includes: extracting each sample curve of torque variation with drilling depth corresponding to the instability of the coal seam stored in the database, recording it as each abnormal torque variation with drilling depth sample curve, comparing the torque variation curve with drilling depth during coal seam drilling with each abnormal torque variation with drilling depth sample curve, obtaining the length of the curve segment in the torque variation curve with drilling depth during coal seam drilling, whose shape similarity with each abnormal torque variation with drilling depth sample curve is greater than a set similarity threshold, recording it as the length of the curve segment in the torque variation curve with drilling depth during coal seam drilling that matches each abnormal torque variation with drilling depth sample curve, and expressing it as , Indicates The number of the sample curve of abnormal torque changing with drilling depth, .

[0071] By analyzing the formula Obtain the coal seam stability coefficient of drilling torque guidance ,in The correction factor for the seam stability factor of the preset drilling torque steering, Indicates the preset The influence weight of the sample curve of abnormal torque changing with drilling depth is , It represents the length of the curve of torque changing with drilling depth during coal seam drilling.

[0072] It should be noted that during the coal seam drilling process, if there are abnormal torque changes such as sudden increase in torque, violent torque fluctuations, continuous increase in torque and inability to stabilize, it means that the coal seam is unstable.

[0073] In this embodiment, the present invention monitors the drilling torque, an important indicator for evaluating coal seam stability, in real time. If the drilling torque suddenly increases, it may mean that the coal seam ahead has encountered hard rocks or geological structures, and there is a potential danger. This can provide early warning for engineering personnel, so that they can take corresponding safety measures to avoid accidents.

[0074] Step 3: Coal seam drilling vibration monitoring and analysis: obtain the vibration amplitude and vibration frequency of the drill bit at each monitoring time point during the coal seam drilling process, draw the curve of the vibration amplitude and vibration frequency changing with time during the coal seam drilling process, and further evaluate the coal seam stability coefficient guided by drilling vibration.

[0075] As a preferred solution, the specific analysis process of step three includes: obtaining the vibration amplitude and vibration frequency of the drill bit at each monitoring time point during the coal seam drilling process through a vibration monitor.

[0076] It should be noted that the vibration monitor can detect the vibration amplitude and frequency in different directions. The vibration monitor can be installed on the body, drill rod or other key parts of the drilling rig.

[0077] A coordinate system is established with the monitoring time point as the horizontal axis and the vibration amplitude as the vertical axis. According to the vibration amplitude of the drill bit at each monitoring time point during the coal seam drilling process, the corresponding data points are marked in the coordinate system. The mathematical model establishment method is used to draw a curve of the change of vibration amplitude over time during the coal seam drilling process.

[0078] Similarly, according to the method for obtaining the curve of the vibration amplitude changing with time during the coal seam drilling process, the curve of the vibration frequency changing with time during the coal seam drilling process is obtained.

[0079] The peak points of the curve of the vibration amplitude changing with time during coal seam drilling are obtained, and the peak deviation of each peak point is obtained. If the peak deviation of a peak point is greater than the preset peak deviation threshold, the peak point is recorded as a vibration amplitude abnormal point, and the peak deviation of the peak point is recorded as the relative deviation of the vibration amplitude. The relative deviation of the vibration amplitude of each vibration amplitude abnormal point in the curve of the vibration amplitude changing with time during coal seam drilling is counted and recorded as , Indicates The number of the abnormal vibration amplitude point, .

[0080] It should be noted that the peak deviation of the peak point refers to the difference between the peak value of the peak point on the curve, that is, the maximum positive amplitude value and the stable value of the curve. This difference can be used to measure the degree of deviation of the curve from the stable state at the peak.

[0081] By analyzing the formula Obtain the first coefficient of coal seam stability under drilling vibration guidance ,in The correction factor of the first coefficient of coal seam stability for the preset drilling vibration guidance, Indicates the preset threshold value of the relative deviation of the vibration amplitude.

[0082] It should be noted that during the coal seam drilling process, if there are abnormal vibration amplitude changes such as a sudden increase in vibration amplitude, a continuous increase in vibration amplitude and an inability to stabilize, it means that the coal seam is unstable.

[0083] As a preferred solution, the specific analysis process of step 3 further includes: according to the curve of vibration frequency changing with time during coal seam drilling, obtaining the number of fluctuations of vibration frequency during coal seam drilling, the average fluctuation amount and the disorder degree of the curve of vibration frequency changing with time, which are recorded as .

[0084] By analyzing the formula The second coefficient of coal seam stability under drilling vibration guidance is obtained ,in The correction factor of the second coefficient of coal seam stability for the preset drilling vibration guidance, They represent the preset vibration frequency fluctuation times, vibration frequency fluctuation amount, and the threshold value of the degree of disorder of the vibration frequency change curve over time. They respectively represent the preset number of vibration frequency fluctuations, the vibration frequency fluctuation amount, and the weights of the degree of disorder of the vibration frequency variation curve over time. .

[0085] It should be noted that the degree of disorder of the curve of vibration frequency variation over time can be obtained through data acquisition system and software analysis.

[0086] It should be noted that during the coal seam drilling process, if there are abnormal vibration frequency changes such as sudden changes in vibration frequency or disordered vibration frequency, it means that the coal seam is unstable.

[0087] The weighted average of the first coefficient of coal seam stability guided by drilling vibration and the second coefficient of coal seam stability guided by drilling vibration is calculated to obtain the coal seam stability coefficient guided by drilling vibration, which is expressed as .

[0088] It should be noted that the weights of the first coefficient of coal seam stability guided by drilling vibration and the second coefficient of coal seam stability guided by drilling vibration are set values, and the cumulative sum is 1.

[0089] In this embodiment, the present invention can timely detect changes in coal seam stability by real-time monitoring of drilling vibration amplitude and vibration frequency, which are important indicators for coal seam stability assessment. When the vibration amplitude suddenly increases or the frequency fluctuates abnormally, it may indicate that there are unstable factors in the coal seam ahead, such as broken zones, faults, etc., thereby providing timely early warning information for engineering personnel to take corresponding safety measures to avoid accidents.

[0090] Step 4. Comprehensive evaluation of coal seam stability: Analyze the comprehensive evaluation index of coal seam stability based on the drilling speed-guided coal seam stability coefficient, the drilling torque-guided coal seam stability coefficient, and the drilling vibration-guided coal seam stability coefficient.

[0091] As a preferred solution, the specific analysis process of step 4 is: the coal seam stability coefficient guided by the drilling speed , Coal seam stability coefficient of drilling torque guidance , Coal seam stability coefficient of drilling vibration guidance Substitute into the analysis formula Obtain the comprehensive evaluation index of coal seam stability ,in Represents the correction factor of the preset comprehensive evaluation index of coal seam stability, represent the thresholds of the preset drilling speed-guided coal seam stability coefficient, the drilling torque-guided coal seam stability coefficient, and the drilling vibration-guided coal seam stability coefficient, respectively. They respectively represent the weights of the preset drilling speed-guided coal seam stability coefficient, the drilling torque-guided coal seam stability coefficient, and the drilling vibration-guided coal seam stability coefficient, .

[0092] Step 5. Coal seam drilling risk warning feedback: Based on the comprehensive assessment index of coal seam stability, determine whether there is a safety risk in continuing to drill into the coal seam. If there is a safety risk, a warning will be issued and feedback will be given to the coal seam drilling construction supervision department.

[0093] As a preferred scheme, the specific analysis process of step five is: comparing the comprehensive evaluation index of coal seam stability with the preset warning value of the comprehensive evaluation index of coal seam stability; if the comprehensive evaluation index of coal seam stability is less than the preset warning value of the comprehensive evaluation index of coal seam stability, there is a safety risk in continuing to drill the coal seam, and an early warning is issued and fed back to the coal seam drilling construction supervision department.

[0094] The above contents are merely examples and explanations of the concept of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the concept of the invention or exceed the scope defined by the present invention, they shall all fall within the protection scope of the present invention.

Claims

1. A method for predicting coal seam stability based on coal seam drilling status, characterized in that: The steps include: Step 1: Coal seam drilling speed monitoring and analysis: obtain the drilling speed and drilling depth at each monitoring time point during the coal seam drilling process, identify the abnormal drilling speed time points during the coal seam drilling process, analyze the relative deviation of the drilling speed at each abnormal drilling speed time point, and further evaluate the drilling speed-guided coal seam stability coefficient; Step 2: Coal seam drilling torque monitoring and analysis: Obtain the torque and drilling depth at each monitoring time point during coal seam drilling, draw a curve of torque variation with drilling depth during coal seam drilling, and compare it with the corresponding sample curves of torque variation with drilling depth when the coal seam is unstable, so as to further evaluate the coal seam stability coefficient guided by drilling torque; Step 3: Coal seam drilling vibration monitoring and analysis: Obtain the vibration amplitude and vibration frequency of the drill bit at each monitoring time point during coal seam drilling, draw the curve of the change of vibration amplitude over time and the curve of the change of vibration frequency over time during coal seam drilling, and further evaluate the coal seam stability coefficient guided by drilling vibration; Step 4: Comprehensive evaluation of coal seam stability: Analyze the comprehensive evaluation index of coal seam stability based on the drilling speed-guided coal seam stability coefficient, the drilling torque-guided coal seam stability coefficient, and the drilling vibration-guided coal seam stability coefficient; Step 5: Coal seam drilling risk warning feedback: Based on the comprehensive assessment index of coal seam stability, determine whether there is a safety risk in continuing to drill into the coal seam. If there is a safety risk, issue a warning and feedback to the coal seam drilling construction supervision department; The specific analysis process of step 1 includes: Set the time interval for data collection, and further set various monitoring time points during the coal seam drilling process according to the principle of equal time intervals; The drilling speed at each monitoring time point during the coal seam drilling process is obtained through a drilling speed monitoring instrument, and the drilling depth at each monitoring time point during the coal seam drilling process is obtained through a depth recorder; If the difference in drilling speed between a certain monitoring time point and its previous adjacent monitoring time point during coal seam drilling is greater than a preset drilling speed difference threshold, the monitoring time point during coal seam drilling is recorded as an abnormal drilling speed time point, and each abnormal drilling speed time point during coal seam drilling is counted; The specific analysis process of step 1 also includes: Obtain the difference in drilling speed between each abnormal drilling speed time point and its adjacent previous monitoring time point during coal seam drilling, and record it as , Indicates The number of the time point when the turning speed is abnormal, , and obtain the difference between the drilling pressure and drill bit speed at each abnormal drilling speed time point and its adjacent previous monitoring time point during coal seam drilling, and record them as ; By analyzing the formula Get the relative deviation of drilling speed at each abnormal drilling speed time point ,in Indicates the preset compensation amount of drilling speed difference. They respectively represent the thresholds of the preset drilling pressure difference and drill bit speed difference.

2. A method for predicting coal seam stability based on coal seam drilling status according to claim 1, characterized in that: The specific analysis process of step 1 also includes: The abnormal time points of each drilling speed during the coal seam drilling process are recorded as the time points corresponding to each change of coal seam hardness during the coal seam drilling process. The average frequency of the change of coal seam hardness during the coal seam drilling process is further obtained and recorded as ; According to the drilling depth at each monitoring time point during the coal seam drilling process, the drilling depth corresponding to each change in coal seam hardness during the coal seam drilling process is screened and recorded as , Indicates the hardness of the coal seam during coal seam drilling. The number of the change. ; Substitute the relative deviation of the drilling speed at each abnormal time point during the coal seam drilling process into the relationship function between the relative deviation of the drilling speed and the change in coal seam hardness stored in the database to obtain the change in hardness corresponding to each change in coal seam hardness during the coal seam drilling process, which is recorded as ; By analyzing the formula Obtain the drilling speed-guided coal seam stability coefficient ,in The correction factor for the coal seam stability factor for the preset drilling speed guidance, represents a natural constant, Respectively represent the weight factors of the preset frequency and amount of change of coal seam hardness, , They represent the preset thresholds of the change frequency and change amount of the coal seam hardness, Indicates the impact factor corresponding to the preset unit drilling depth.

3. A method for predicting coal seam stability based on coal seam drilling status according to claim 2, characterized in that: The specific analysis process of step 2 includes: The torque at each monitoring time point during coal seam drilling is obtained through a torque monitor; A coordinate system is established with drilling depth as the horizontal axis and torque as the vertical axis. According to the torque and drilling depth at each monitoring time point during coal seam drilling, the corresponding data points are marked in the coordinate system. The mathematical model establishment method is used to draw a curve of the change of torque with drilling depth during coal seam drilling.

4. A method for predicting coal seam stability based on coal seam drilling status according to claim 3, characterized in that: The specific analysis process of step 2 also includes: The sample curves of torque variation with drilling depth corresponding to the unstable coal seam stored in the database are extracted and recorded as sample curves of abnormal torque variation with drilling depth. The curve of torque variation with drilling depth in the coal seam drilling process is compared with the sample curves of abnormal torque variation with drilling depth, and the length of the curve segment whose shape similarity with the sample curves of abnormal torque variation with drilling depth in the curve of torque variation with drilling depth in the coal seam drilling process is obtained, and the length of the curve segment whose shape similarity with the sample curves of abnormal torque variation with drilling depth in the curve of torque variation with drilling depth in the coal seam drilling process is greater than the set similarity threshold is obtained. The curve segment is recorded as the length of the curve segment that matches the sample curves of abnormal torque variation with drilling depth in the curve of torque variation with drilling depth in the coal seam drilling process, and is expressed as , Indicates The number of the sample curve of abnormal torque changing with drilling depth, ; By analyzing the formula Obtain the coal seam stability coefficient of drilling torque guidance ,in The correction factor for the seam stability factor of the preset drilling torque steering, Indicates the preset The influence weight of the sample curve of abnormal torque changing with drilling depth is , It represents the length of the curve of torque changing with drilling depth during coal seam drilling.

5. A method for predicting coal seam stability based on coal seam drilling status according to claim 4, characterized in that: The specific analysis process of step three includes: The vibration amplitude and vibration frequency of the drill bit at each monitoring time point during coal seam drilling are obtained through a vibration monitor; A coordinate system is established with the monitoring time point as the horizontal axis and the vibration amplitude as the vertical axis. According to the vibration amplitude of the drill bit at each monitoring time point during the coal seam drilling process, the corresponding data points are marked in the coordinate system. The curve of the vibration amplitude changing with time during the coal seam drilling process is drawn using the method of establishing a mathematical model. Similarly, according to the method for obtaining the curve of the vibration amplitude changing with time during the coal seam drilling process, the curve of the vibration frequency changing with time during the coal seam drilling process is obtained; The peak points of the curve of the vibration amplitude changing with time during coal seam drilling are obtained, and the peak deviation of each peak point is obtained. If the peak deviation of a peak point is greater than the preset peak deviation threshold, the peak point is recorded as a vibration amplitude abnormal point, and the peak deviation of the peak point is recorded as the relative deviation of the vibration amplitude. The relative deviation of the vibration amplitude of each vibration amplitude abnormal point in the curve of the vibration amplitude changing with time during coal seam drilling is counted and recorded as , Indicates The number of the abnormal vibration amplitude point, ; By analyzing the formula Obtain the first coefficient of coal seam stability under drilling vibration guidance ,in The correction factor of the first coefficient of coal seam stability for the preset drilling vibration guidance, Indicates the preset threshold value of the relative deviation of the vibration amplitude.

6. A method for predicting coal seam stability based on coal seam drilling status according to claim 5, characterized in that: The specific analysis process of step three also includes: According to the curve of vibration frequency changing with time during coal seam drilling, the number of fluctuations of vibration frequency, the average fluctuation amount and the disorder degree of the curve of vibration frequency changing with time during coal seam drilling are obtained, which are recorded as ; By analyzing the formula The second coefficient of coal seam stability under drilling vibration guidance is obtained ,in The correction factor of the second coefficient of coal seam stability for the preset drilling vibration guidance, They represent the preset vibration frequency fluctuation times, vibration frequency fluctuation amount, and the threshold value of the degree of disorder of the vibration frequency change curve over time. They respectively represent the preset number of vibration frequency fluctuations, the vibration frequency fluctuation amount, and the weights of the degree of disorder of the vibration frequency variation curve over time. ; The weighted average of the first coefficient of coal seam stability guided by drilling vibration and the second coefficient of coal seam stability guided by drilling vibration is calculated to obtain the coal seam stability coefficient guided by drilling vibration, which is expressed as .

7. A method for predicting coal seam stability based on coal seam drilling status according to claim 6, characterized in that: The specific analysis process of step 4 is as follows: Coal seam stability factor that guides drilling speed , Coal seam stability coefficient of drilling torque guidance , Coal seam stability coefficient of drilling vibration guidance Substitute into the analysis formula Obtain the comprehensive evaluation index of coal seam stability ,in Represents the correction factor of the preset comprehensive evaluation index of coal seam stability, They respectively represent the thresholds of the preset drilling speed-guided coal seam stability coefficient, the drilling torque-guided coal seam stability coefficient, and the drilling vibration-guided coal seam stability coefficient, They respectively represent the weights of the preset drilling speed-guided coal seam stability coefficient, the drilling torque-guided coal seam stability coefficient, and the drilling vibration-guided coal seam stability coefficient, .

8. The method for predicting coal seam stability based on coal seam drilling status according to claim 1, characterized in that: The specific analysis process of step five is as follows: The comprehensive assessment index of coal seam stability is compared with the preset warning value of the comprehensive assessment index of coal seam stability. If the comprehensive assessment index of coal seam stability is less than the preset warning value of the comprehensive assessment index of coal seam stability, there is a safety risk in continuing to drill into the coal seam, and a warning is issued and fed back to the coal seam drilling construction supervision department.

Images