A method for analyzing and evaluating pressure-relief effect of a borehole

Abstract

This invention discloses a method for analyzing and evaluating the pressure relief effect of borehole drilling, relating to the field of coal mine dynamic disaster monitoring and prevention technology. The method includes: deploying a rope-type displacement acquisition device at the hydraulic drilling rig in the coal mine, and deploying a vibration signal acquisition device on the roadway side adjacent to the borehole; calculating the drilling depth for pressure relief based on displacement and vibration change data; obtaining the average amplitude per meter of depth by statistically analyzing the drilling time and vibration amplitude at different borehole depths; acquiring the distribution of lateral support pressure in the roadway based on the average amplitude per meter of depth; and evaluating the pressure relief effect of the borehole based on the distribution of lateral support pressure in the roadway. This invention enables accurate acquisition of vibration signals at different drilling depths, solving the current technical problems of crude borehole construction quality verification and weak pressure relief effect evaluation and analysis, providing reliable technical support for the prevention and control of coal mine dynamic disasters.

Description

Technical Field

[0001] This invention relates to the field of coal mine dynamic disaster monitoring and prevention technology, and in particular to a method for analyzing and evaluating the stress relief effect of boreholes in the process of mine drilling, which can realize integrated monitoring and evaluation of borehole construction quality, regional stress distribution and stress relief effect. Background Technology

[0002] With the increasing depth of coal mining in my country, dynamic disasters such as rockbursts have become a key bottleneck restricting safe production in coal mines. Borehole depressurization, as a core technology for preventing rockbursts, directly determines the effectiveness of disaster prevention and control through its construction quality and depressurization effect. Currently, the coal mining industry mainly relies on microseismic monitoring systems and traditional drill cuttings methods for relevant evaluations, but these methods have many technical shortcomings:

[0003] Missing capture of micro-scale disturbance signals: Existing microseismic monitoring systems mainly target low-frequency and medium-to-high-frequency vibration signals at the mine field or working face scale, and cannot effectively capture high-frequency vibration signals generated during drilling operations (such as drill bit rock-breaking vibration, drill rod resonance, etc.). These signals directly reflect the stress state, coal and rock mass fracture characteristics, and stress relief effect in the borehole pressure relief construction area.

[0004] Limited adaptability to complex well conditions: Existing vibration monitoring devices have limited adaptability to the high temperature and humidity environment of deep mines, which can easily lead to corrosion of their circuit boards. Furthermore, the dust generated during drilling can clog the sensors, further affecting their accuracy.

[0005] Construction quality verification is crude: construction quality indicators such as drilling depth and drilling efficiency mainly rely on manual spot checks or drill rod counting, which has large errors, low efficiency, and makes it difficult to achieve dynamic control throughout the entire process.

[0006] Weak data fusion and intelligent analysis capabilities: Existing technologies cannot integrate multi-source data such as stress distribution, vibration characteristics, and construction parameters, making it difficult to form a comprehensive quantitative assessment of the impact hazard level in the borehole area. Furthermore, existing monitoring and evaluation methods have significant limitations. The theoretical calculation-based comprehensive index method relies on experience and statistical results from past disasters, making it difficult to adapt to the complex and diverse causes and triggering factors of rockbursts. The probability index method, based on fuzzy mathematics theory and empirical data, cannot guarantee accuracy. In multi-factor coupled evaluations, the stress increase coefficients for many factors are selected empirically, leading to a significant reduction in the reliability of the final calculated stress value. The only practical data-based method, the drill cuttings method, is not only susceptible to significant errors due to human factors during drilling and weighing, but also increases the workload of on-site personnel.

[0007] Therefore, there is an urgent need to develop a drilling monitoring technology and equipment that can accurately capture drilling vibration signals, achieve simultaneous acquisition of multiple parameters, and support intelligent analysis and evaluation, so as to fill the technological gap in refined monitoring of drilling operations. Summary of the Invention

[0008] In view of this, embodiments of the present invention provide a method for analyzing and evaluating the pressure relief effect of borehole drilling, which solves the technical problems of current crude verification of borehole construction quality and weak evaluation and analysis of pressure relief effect.

[0009] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0010] A method for analyzing and evaluating the effect of borehole pressure relief includes:

[0011] Step S100: Install a rope-type displacement acquisition device at the hydraulic drilling rig in the coal mine, and install a vibration signal acquisition device on the roadway side near the borehole. The rope-type displacement acquisition device records the displacement change data between the movable propulsion device and the fixed guide device at the front end of the guide rail of the hydraulic drilling rig in the coal mine, and the vibration signal acquisition device records the vibration change data of the borehole pressure relief project.

[0012] Step S200: Based on the analysis of displacement change data and vibration change data, calculate the construction depth of the pressure relief borehole;

[0013] Step S300: By statistically analyzing the drilling time and vibration amplitude at different drilling depths, the average amplitude per meter of depth is obtained;

[0014] Step S400: Obtain the distribution of lateral support pressure in the roadway based on the average amplitude per meter depth;

[0015] Step S500: Evaluate the borehole pressure relief effect by analyzing the distribution of lateral support pressure in the roadway.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] The borehole pressure relief effect analysis and evaluation method provided in this invention can accurately collect vibration signals at different drilling depths, solving the technical problems of current crude borehole construction quality verification and weak pressure relief effect evaluation and analysis, and providing reliable technical support for the prevention and control of coal mine dynamic disasters. Specifically, this invention uses a rope-type displacement acquisition device and a vibration signal acquisition device to jointly monitor multiple parameters of the pressure relief borehole construction depth. The monitoring results are more accurate than traditional identification methods that rely solely on vibration parameters. Compared with the traditional "drill cuttings method," it does not require separate drilling; on-site data collection can be completed during the construction of the mine pressure relief hole, greatly reducing the amount of construction work while ensuring the accuracy of the evaluation. Attached Figure Description

[0018] The accompanying drawings in this application are intended to supplement the textual description in the specification with graphics, and to further explain the technical solution of this application. They do not constitute an undue limitation on this application.

[0019] Figure 1 This is a flowchart illustrating the drilling pressure relief effect analysis and evaluation method of the present invention;

[0020] Figure 2 This is a schematic diagram of the drilling pressure relief effect analysis and evaluation method of the present invention;

[0021] Figure 3 This is a layout diagram of the multi-parameter portable drilling data acquisition device in this invention;

[0022] Figure 4 This is a bar chart of amplitude and a line graph of displacement under a unified time axis in this invention;

[0023] Figure 5 This is an example of a borehole lateral support pressure cloud diagram in this invention.

[0024] Figure label:

[0025] 1-Portable drilling data acquisition instrument, 2-Wire rope displacement sensor, 3-Moving coil sensor, 4-Transmission cable, A-Road roof, B-Road floor, C-Drilling location, D-Road side. Detailed Implementation

[0026] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0027] In the description of this invention, it should be understood that the terms "center," "lateral," "longitudinal," "front," "rear," "left," "right," "upper," "lower," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the scope of protection of this invention.

[0028] This invention provides a method for analyzing and evaluating the pressure relief effect of boreholes. This evaluation method is mainly applied to pressure relief boreholes, especially large-diameter pressure relief boreholes, without the need for additional drilling, thus saving on engineering work. Figure 1-2 As shown, the evaluation method includes:

[0029] Step S100: Install a rope-type displacement acquisition device at the hydraulic drilling rig in the coal mine, and install a vibration signal acquisition device on the roadway side near the borehole. The rope-type displacement acquisition device records the displacement change data between the movable propulsion device and the fixed guide device at the front end of the guide rail of the hydraulic drilling rig in the coal mine, and the vibration signal acquisition device records the vibration change data of the borehole pressure relief project.

[0030] In this step, one end of the rope-type displacement acquisition device is fixed to the movable propulsion device at the guide rail of the coal mine hydraulic drilling rig, and the other end is fixed to the fixed guide device at the front end of the guide rail of the coal mine hydraulic drilling rig. This process needs to be arranged in place before drilling construction, and the displacement change data acquisition is completed after drilling construction.

[0031] As an optional embodiment, the wire-stayed displacement acquisition device includes a portable drilling data acquisition instrument and a wire-stayed displacement sensor connected to the portable drilling data acquisition instrument; the vibration signal acquisition device includes a portable drilling data acquisition instrument and a moving coil sensor connected to the portable drilling data acquisition instrument.

[0032] In specific implementation, such as Figure 3 As shown, both the wire-stayed displacement acquisition device and the vibration signal acquisition device include a portable drilling data acquisition instrument 1 (the two can share a single portable drilling data acquisition instrument); wherein: the wire-stayed displacement acquisition device also includes a wire-stayed displacement sensor 2; the vibration signal acquisition device also includes a moving coil sensor 3. Due to the limited number of acquisition instrument interfaces, the number of moving coil sensors 3 is at most two; the portable drilling data acquisition instrument 1 is connected to the wire-stayed displacement sensor 2 and the moving coil sensor 3 respectively through sensing cables 4 to complete the acquisition and transmission of displacement change data and vibration signals (i.e., vibration change data).

[0033] The portable drilling data acquisition instrument 1 selected in this embodiment of the invention adopts a 24-bit high-precision design and integrates data acquisition, storage, and time synchronization functions. Its technical parameters are as follows:

[0034] (1) Number of channels: 1~3 channels (1 channel for displacement, 2 channels for vibration);

[0035] (2) Sampling frequency: 2kHz;

[0036] (3) Timing method: Ground GPS satellite timing + high-precision clock chip;

[0037] (4) Operating voltage: 3.6V;

[0038] (5) Data storage: Built-in 16G storage module;

[0039] (6) Working time: It can work continuously for more than 80 hours on a full charge;

[0040] (7) External dimensions: 240mm×280mm×85mm;

[0041] (8) Structural design: The rechargeable battery, display screen and circuit are separately waterproofed;

[0042] (9) Weight: 2.8kg.

[0043] The draw-wire displacement sensor 2 selected in this embodiment of the invention is used to monitor displacement changes during the drilling process, and its technical parameters are as follows:

[0044] (1) Measuring range: 0~3000mm;

[0045] (2) Power supply voltage: DC12~24V;

[0046] (3) Output signal accuracy: better than ±0.12% FS;

[0047] (4) Linearity accuracy: 50m;

[0048] (5) Operating temperature: -30~85℃;

[0049] (6) Seismic performance: 10g (5~2000Hz);

[0050] (7) Connection method: Four-core data transmission cable.

[0051] The moving coil sensor 3 selected in this embodiment of the invention is a quick-connect high-frequency acquisition moving coil velocity sensor used to capture the vibration signals of coal and rock breaking and the drilling rig itself during drilling. Its technical parameters are as follows:

[0052] (1) Sensor type: Quick-connect high-frequency acquisition moving coil speed sensor;

[0053] (2) Sensitivity: 100V / m / s;

[0054] (3) Maximum transmission distance: 50m;

[0055] (4) Connection method: Two-core data transmission cable;

[0056] (5) Vibration tolerance: Acceleration 50m / s²;

[0057] (6) Impact resistance: peak acceleration 500m / s².

[0058] The transmission cable 4 selected in this embodiment of the invention includes a two-core vibration signal transmission cable and a four-core displacement signal transmission cable, which has the characteristics of anti-electromagnetic interference and resistance to moisture and dust, and is suitable for complex underground environments.

[0059] The vibration signal acquisition device is deployed before drilling. The portable drilling data acquisition instrument 1 collects displacement and vibration change data during drilling and completes data acquisition after drilling is completed. Figure 3 As shown, in this embodiment, one of the aforementioned pull-rope type displacement sensors 2 is used, with one end fixed to a movable propulsion device at the guide rail of the coal mine hydraulic drilling rig, and the other end fixed to a guide device at the front end of the guide rail of the coal mine hydraulic drilling rig; two of the aforementioned moving coil sensors 3 are arranged on both sides of the borehole at a distance of 1 meter, and the borehole is a pressure relief borehole. Figure 3 Point A is the tunnel roof, point B is the tunnel floor, point C is the location for the pressure relief drilling, and point D is the tunnel sidewall.

[0060] In other embodiments, the spacing between the moving coil sensors 3 of the vibration acquisition device can be other distances, such as 0.5 meters, 2 meters, 3 meters, 5 meters, etc. The specific number of moving coil sensors and the spacing between them can be set according to the actual drilling site conditions.

[0061] The specific layout and data acquisition process of the portable drilling data acquisition device are as follows:

[0062] (1) Installation of the pull-rope displacement sensor: One end of the pull-rope displacement sensor 2 is fixed to the movable propulsion device at the guide rail of the coal mine hydraulic drilling rig by a strong magnet, and the other end is fixed to the guide device at the front end of the guide rail of the coal mine hydraulic drilling rig by a strong magnet.

[0063] (2) Installation of moving coil sensor: Tighten and fix the end of each moving coil sensor 3 to the end of the anchor bolt at the roadway D. There are two moving coil sensors 3, which are respectively arranged 1m on the left and right sides of the pressure relief borehole; suspend and fix the portable drilling data acquisition instrument 1 on the metal mesh on the surface of the roadway D.

[0064] (3) Equipment connection: The portable drilling data acquisition instrument 1 is connected to the wire-type displacement sensor 2 and each moving coil sensor 3 respectively through the transmission cable 4;

[0065] (4) Data acquisition preparation and start-up: Before the pressure relief drilling construction, after confirming that the portable drilling data acquisition instrument 1, the rope displacement sensor 2, and each moving coil sensor 3 are reliably connected, turn on the data acquisition instrument switch; after the switch is turned on, if the data acquisition instrument display light up normally, it indicates that the equipment has been started and the connection status is good, and then monitor the pressure relief drilling construction.

[0066] (5) Data acquisition ends: After the pressure relief drilling is completed, turn off the switch of the portable data acquisition instrument 1 to complete a single data acquisition.

[0067] (6) Cyclic data acquisition operation: Remove each of the arranged moving coil sensors 3, move them and install them 1m to the left and right sides of the next pressure relief drilling hole to be constructed, repeat the above steps (1)-(5) to start the next round of data acquisition cycle.

[0068] (7) Battery replacement: After collecting data for a week, if the battery power of the portable drilling data acquisition instrument 1 is lower than the preset threshold, replace the battery in time to ensure the continuity of data acquisition.

[0069] The core acquisition principle of the rope-type displacement acquisition device is as follows:

[0070] During the construction of large-diameter pressure relief boreholes, there is a clear correspondence between the working state and displacement change characteristics of the hydraulic drilling rig used in coal mines after startup:

[0071] (1) Drilling stage: Due to the obstruction of the coal and rock mass, the distance between the movable propulsion device at the guide rail and the guide device at the front end of the guide rail changes slowly; and as the drilling operation progresses, the relative distance between the two tends to increase.

[0072] (2) Retraction stage: The drilling rig is removed from the obstruction of the coal and rock mass, and the distance between the two components changes rapidly; and as the drilling rig retraction operation progresses, the relative distance between the two tends to decrease. The direction of distance change in the retraction stage is completely opposite to that in the drilling stage.

[0073] (3) Drill pipe replacement stage: The distance between the two components remains unchanged.

[0074] Based on the above characteristics, by using a rope-type displacement acquisition device to collect real-time displacement change data between the two components, it is possible to accurately distinguish between the three working states of the drilling rig: drilling, retraction, and drill rod replacement, thereby accurately calculating the actual drilling depth. This acquisition principle can effectively correct the systematic bias in traditional drilling monitoring that easily misjudges the retraction process as the drilling process, thus improving the accuracy of drilling depth monitoring.

[0075] The core acquisition principle of the vibration signal acquisition device is as follows:

[0076] During the construction of large-diameter pressure relief boreholes, the drilling system, consisting of a drilling rig, drill rod, and drill bit, generates multi-source vibration signals when operating in the coal and rock mass:

[0077] (1) The drill bit directly generates vibration signals when cutting coal and rock mass;

[0078] (2) Under the combined force of the drill bit and the drilling rig, the drill rod generates triaxial vibration in the axial, tangential and rotational directions;

[0079] (3) The drilling rig is affected by the vibration transmitted by the drill rod and generates a vibration signal synchronously.

[0080] (4) Under the condition that the physical and mechanical properties of the coal are consistent, the intensity of the above vibration signal is positively correlated with the stress of the coal.

[0081] Meanwhile, the construction of the pressure relief borehole will disrupt the original stress balance of the coal body. During the stress redistribution process, vibration signals may be triggered. These vibration signals correspond to the fracturing process of the coal and rock mass. The drilling depth at the time of fracturing can be determined by the vibration signals, but the specific spatial location of the fracturing cannot be directly located. When the above vibration signal is transmitted to the installation position of the moving coil sensor 3, the coil inside the sensor moves synchronously with the external vibration and cuts the magnetic field lines, causing an induced electromotive force to be generated at both ends of the coil. This converts the vibration signal, characterized by vibration velocity (unit: m / s), into an electrical signal (unit: mV) and forms a waveform file. This electrical signal is transmitted to the portable drilling data acquisition instrument 1 through the transmission cable 4. The acquisition instrument records the change data of the induced electromotive force at a preset sampling frequency and stores the data in the built-in SD card, completing the acquisition and storage of the vibration signal (i.e., vibration change data).

[0082] Step S200: Based on the analysis of displacement change data and vibration change data, calculate the construction depth of the pressure relief borehole;

[0083] As an optional embodiment, step S200 includes:

[0084] Step S201: Based on the significant amplitude clustering characteristics presented during the drilling process, perform feature identification and calculation on the vibration change data to generate preliminary drilling depth data;

[0085] Before this step, the displacement and vibration data can be exported to provide a basic data source for subsequent data processing and depth calculation. In this step, based on the significant amplitude clustering characteristics exhibited during drilling, the vibration data is subjected to feature identification and calculation to generate preliminary drilling depth data. This is a conventional technique in the field and will not be elaborated here. However, since this preliminary data has systematic biases, specifically the tendency to misjudge the drill retraction process as the drilling process, it is impossible to accurately distinguish between the drilling and drill retraction stages, leading to errors in the calculation of the borehole depth. Therefore, in subsequent steps, displacement data needs to be introduced to carry out multi-parameter collaborative correction.

[0086] Step S202: Based on the differential pattern of displacement change rate, identify the operation stage of displacement change data to accurately distinguish between the drilling process and the withdrawal process; wherein, during the drilling process, the displacement change rate is characterized by low speed, and during the withdrawal process, the displacement change rate is characterized by high speed.

[0087] In this step, the influence of the rock mass on the drilling operation is considered: during the drilling process, the displacement change rate between the movable propulsion device at the guide rail and the fixed guide device at the front end of the guide rail of the coal mine hydraulic drilling rig is characterized by low speed; during the retraction process, the displacement change rate is characterized by high speed; based on the differential law of the displacement change rate, the operation stage is identified by the displacement change data, so as to accurately distinguish between the drilling process and the retraction process.

[0088] Step S203: Based on the results of the operation stage identification, the preliminary drilling depth data is corrected, the drilling withdrawal process is removed, and only the drilling process is retained. Through data verification and optimization calculation, the target drilling depth data is generated.

[0089] In this step, by identifying displacement change data, the drilling process and the withdrawal process are distinguished. Based on this, the preliminary drilling depth data generated in step S201 is corrected, the withdrawal process is removed, and only the drilling process is retained. Through data verification and optimization calculations (various algorithms in this field can be used, such as data cleaning: using amplitude limiting filtering combined with distribution characteristics to remove outliers; dynamic preprocessing: sliding window Savitzky-Golay filtering to improve data quality; error correction: correcting out-of-tolerance values ​​point by point to ensure data continuity; parameter adaptation: supporting dynamic adjustment of window length and error threshold, etc.), the target drilling depth data is generated.

[0090] Step S300: By statistically analyzing the drilling time and vibration amplitude at different drilling depths, the average amplitude per meter of depth is accurately obtained;

[0091] In this step, based on the drilling depth after multi-parameter joint identification, the drilling time per meter depth is counted, and the average amplitude per meter depth is calculated (specifically, it can be obtained by taking the average value of the vibration amplitude detected at different depths by the moving coil sensor 3 set at 1m on each side of the pressure relief borehole).

[0092] Step S400: Obtain the distribution of lateral support pressure in the roadway based on the average amplitude per meter depth;

[0093] As an optional embodiment, step S400 further comprises:

[0094] The distribution of lateral support pressure in the roadway is obtained based on the average amplitude per meter depth and the pre-established lateral support pressure inversion model.

[0095] Therefore, the distribution of lateral support pressure in the roadway can be obtained by inverting the average amplitude at different drilling depths.

[0096] Preferably, the method for establishing the lateral support pressure inversion model includes:

[0097] Step A1: Obtain the average amplitude A of each amplitude cluster during single-hole drilling;

[0098] In this step, the basic data of lateral support pressure is the average amplitude A of each amplitude cluster during single-hole drilling. Before this, the vibration change data can be preprocessed, namely noise reduction and effective vibration identification.

[0099] Step A2: Obtain the lateral support stress σ during single-hole drilling;

[0100] In this step, a stress verification device can be set up: borehole stress gauges are placed near the borehole to directly measure the lateral support stress, which is used for the calibration and verification of the inversion model.

[0101] Step A3: Based on the average amplitude A and the lateral support stress σ, fit and establish the lateral support pressure inversion model.

[0102] This step involves the inversion of lateral support pressure, which is also the construction of the quantitative calibration model of "average amplitude - lateral stress": based on field test data, the lateral support pressure inversion model can be fitted and established.

[0103] The lateral support pressure inversion model can be a linear or nonlinear fitting model:

[0104] Linear model: σ = aA + b;

[0105] This model is applicable to regions with moderate to low stress, where a and b are fitting coefficients.

[0106] Nonlinear model: σ = clnA + d;

[0107] This model is applicable to regions with high stress, and c and d are fitting coefficients.

[0108] Therefore, in this step S400, based on the amplitude data processed above, the distribution law of the lateral support pressure of the roadway can be inverted by combining the "average amplitude-lateral stress" quantitative calibration model.

[0109] In addition, the average amplitude A per meter of borehole depth can be substituted into the above calibration equation to calculate the lateral support pressure data at the corresponding depth. Then, a borehole lateral support pressure cloud map can be drawn using drawing software. The cloud map can intuitively reflect the distribution trend of lateral support pressure along the borehole depth direction.

[0110] Step S500: Evaluate the borehole pressure relief effect by analyzing the distribution of lateral support pressure in the roadway.

[0111] In this step, the pressure distribution along the borehole's lateral support allows for a qualitative evaluation of the borehole's pressure relief effect. The specific evaluation logic and quantitative relationship are as follows:

[0112] The lateral support pressure distribution curve reflects the stress distribution along the borehole depth, with its peak point (denoted as P) representing the stress distribution in the rock mass. max ( ) is the key location for stress concentration in the rock mass and is also the core indicator for judging the stress relief effect;

[0113] During large-diameter pressure relief drilling, the average amplitude of the surrounding rock vibration signals (such as micro-fractures and stress-relief vibrations) induced by borehole disturbance is essentially positively correlated with the lateral support stress in the borehole area. When the lateral support stress is high, borehole disturbances (such as drill bit cutting and borehole wall unloading) easily trigger the release of elastic stored energy in the surrounding rock, resulting in higher energy micro-fracture events and larger amplitude vibration waves during propagation. When the lateral support stress is low, the surrounding rock itself is more stable, and the vibrations induced by borehole disturbances are mainly caused by construction machinery disturbances, with weak energy in micro-fracture vibrations and a significantly reduced average amplitude.

[0114] Therefore, by establishing a quantitative calibration model of "average amplitude-lateral stress", the lateral support stress inversion can be realized, thereby completing the evaluation of the borehole pressure relief effect.

[0115] Formula for evaluating the effectiveness of borehole pressure relief:

[0116] Let the actual drilling depth be H (unit: m), h Pmax Given the borehole depth (in meters) corresponding to the maximum lateral support pressure at the current drilling depth, which can be obtained by retrieving lateral support pressure data using a peak retrieval algorithm, the criteria for determining whether the borehole depth meets the pressure relief requirements are as follows:

[0117] When the following conditions are met:

[0118] H>h Pmax

[0119] This indicates that the drilling operation has penetrated the peak range of lateral support pressure, that is, the stress concentration area where the borehole penetrates the peak value, which has destroyed the original bearing structure of the coal body and can push the peak value to move to the depth of the roadway (away from the roadway surface), achieving the pressure relief target of "high stress zone migration". The drilling parameters and borehole depth have met the pressure relief technical requirements.

[0120] When the conditions are not met, it indicates that the drilling project has not penetrated the peak range of the lateral support pressure, that is, the borehole has not reached the extreme area of ​​stress concentration. The current drilling project is only in the pressure growth section before the peak, which cannot change the stress concentration position and cannot achieve the technical purpose of transferring the peak of the lateral support pressure to the depth of the roadway. The drilling parameters and drilling depth have not met the pressure relief technical requirements, and the drilling parameters need to be further adjusted or the drilling depth increased.

[0121] The technical solution of the present invention will be described in detail below with reference to a specific example.

[0122] I. Source of Example Data

[0123] This example selects the monitoring data of the entire construction process of the No. 2 large-diameter pressure relief borehole in the transport roadway of a certain working face of a mine as the research object. The data types include displacement change data obtained by the rope-type displacement acquisition device and vibration change data obtained by the moving coil sensor. Based on these two types of data, the drilling depth of the borehole, the lateral support pressure inversion and the pressure relief effect judgment are completed.

[0124] II. Calculation and Correction of Drilling Depth

[0125] 1. Preliminary Depth Calculation

[0126] The displacement change data and vibration change data are correlated on a unified time axis to generate an amplitude histogram and a displacement line graph (see...). Figure 4 ).in:

[0127] 1) The “amplitude columnar cluster” (abbreviated as “amplitude cluster”) in the figure corresponds to the drilling process of a single drill rod (one drill rod is connected each time in the field construction).

[0128] 2) The height of the amplitude cluster represents the intensity of the vibration signal generated by the coal body fracturing, the width of the amplitude cluster corresponds to the drilling time, and the gap between the amplitude clusters corresponds to the drill pipe replacement time.

[0129] 3) Based on the calculation relationship of "number of connecting drill rods × length of a single drill rod", the drilling depth of borehole #2 is initially obtained.

[0130] 2. Deep Data Collaborative Correction

[0131] Because the preliminary depth data contains systematic biases, specifically the tendency to misidentify the drill retraction process as the drilling process, and the inability to accurately distinguish between the drilling and drill retraction stages, displacement change data is introduced to conduct multi-parameter collaborative correction. The correction process is as follows:

[0132] 1) An inclination recognition algorithm is adopted, with the criteria of "the inclination of displacement change during the drilling stage is positive, the inclination of displacement change during the drill withdrawal stage is negative, and the inclination of displacement change during the drill pipe replacement stage is 0", to perform full-time retrieval of displacement change data;

[0133] 2) Adjust the number of valid connected drill pipes based on the search results, and in Figure 4 The corrected number of drill pipe connections is indicated in the annotation.

[0134] 3) Combining the length of a single drill rod with a unified time axis, the actual drilling depth of borehole #2 at different times was calculated, and the actual drilling depth of borehole #2 was finally determined to be H=25m.

[0135] III. Vibration Data Processing and Average Amplitude Calculation

[0136] 1. Segmented extraction of vibration data

[0137] Based on the above-calculated "drilling depth-time" correspondence, a time window algorithm is used to extract vibration change data in segments: taking "drilling depth per meter" as a time window, vibration signal data within that depth range is extracted synchronously.

[0138] 2. Vibration data preprocessing

[0139] The segmented vibration signal data were preprocessed sequentially as follows:

[0140] 1) Noise reduction: FFT filtering is used to remove mechanical noise from the equipment and to eliminate outliers generated during data acquisition.

[0141] 2) Vibration signal identification: Based on the preset amplitude threshold (calibrated according to the on-site construction conditions) and vibration duration, valid vibration signals are identified and invalid interference signals are eliminated.

[0142] 3. Effective vibration separation and average amplitude calculation

[0143] Two types of vibration signals were separated through spectral analysis of a dual-moving-coil sensor:

[0144] 1) Regular mechanical disturbance vibration (such as periodic vibration generated during normal operation of a drilling rig).

[0145] 2) Coal micro-fracture vibration (non-periodic vibration caused by stress changes in the coal body due to drilling construction).

[0146] 3) The micro-fracture vibration of the coal body was retained as the effective vibration signal of borehole No. 2, and the effective average vibration amplitude A corresponding to each meter of depth was calculated.

[0147] IV. Lateral Support Pressure Inversion

[0148] 1. Inversion Model Selection and Calibration

[0149] Considering the moderate stress in the coal seam of this transport roadway, a linear fitting equation was selected as the inversion model for lateral support pressure. The calibration equation of this model was obtained based on monitoring data from adjacent boreholes in the mining area, as follows:

[0150] 1) Goodness of fit R 2 =0.87 (indicating that the model fitting accuracy meets engineering requirements);

[0151] 2) Lateral support pressure calibration equation: σ=3.7A+8.1, where σ is the lateral support pressure (unit: MPa) and A is the effective average vibration amplitude per meter depth (unit: mV).

[0152] 2. Pressure data calculation and contour plotting

[0153] Substituting the average amplitude A per meter depth of borehole #2 into the above calibration equation, the lateral support pressure data at the corresponding depth was calculated; the lateral support pressure cloud map of borehole #2 was plotted using drawing software (see...). Figure 5 The cloud map uses color gradients to represent the magnitude of pressure.

[0154] Red area: High stress zone (large lateral support pressure value);

[0155] Blue area: Low stress zone (small lateral support pressure value);

[0156] Cloud maps can intuitively reflect the distribution trend of lateral support pressure along the borehole depth direction.

[0157] 3. Determination of peak pressure and corresponding depth

[0158] A peak retrieval algorithm is used to retrieve lateral support pressure data to determine the borehole depth h corresponding to the maximum lateral support pressure (pressure peak). Pmax =5.8m (corresponding to) Figure 5 (Depth of the red peak region).

[0159] V. Determination of Pressure Relief Effect

[0160] According to the pressure relief effect judgment criterion proposed in this invention, the actual drilling depth of borehole #2 is compared with the depth corresponding to the pressure peak:

[0161] The actual drilling depth H = 25m, and the peak pressure corresponds to the depth h. Pmax =5.8m, which satisfies the criterion H>h. Pmax ;

[0162] Conclusion: Borehole #2 has penetrated the stress concentration core area where the lateral support pressure peak is located, destroying the original bearing structure of the coal body. It can push the pressure peak to the deeper part of the roadway (away from the roadway surface), successfully achieving the pressure relief target of "high stress zone migration". The depth of borehole #2 meets the pressure relief technical requirements.

[0163] In summary, this invention constructs an integrated closed-loop technical system encompassing "drilling construction—stress inversion—effect evaluation," and its core innovation and technological value are reflected in the following two aspects:

[0164] (1) Solve the problem of depth statistical bias in traditional drilling monitoring.

[0165] To address the systematic bias in traditional monitoring while drilling (MSD) for drilling depth statistics—specifically, the tendency to misclassify the drill retraction process as drilling, and the inability to accurately distinguish between drilling and drill retraction stages—this invention introduces displacement change data acquired by a rope-type displacement acquisition device, and performs multi-parameter collaborative correction with vibration change data acquired by a vibration signal acquisition device. Utilizing the differentiated characteristics of displacement change rate under different operating conditions (positive rate during drilling, negative rate during drill retraction, and 0 rate during drill rod replacement), it achieves accurate identification of the drilling rig's "drilling-drill retraction-drill rod replacement" operating conditions, thereby eliminating depth statistical bias and ensuring the accuracy of drilling depth calculation.

[0166] (2) Provide a standardized method for evaluating the depressurization effect.

[0167] Based on the aforementioned accurately acquired drilling depth data and stress inversion results (the lateral support pressure distribution is inverted through amplitude data interpolation, filtering, and normalization), this invention further proposes a quantitative method for evaluating the pressure relief effect. By comparing the relative relationship between the actual drilling depth and the depth corresponding to the maximum lateral support pressure, it determines whether the borehole penetrates the stress concentration zone and whether the peak lateral support pressure is transferred to the deeper part of the roadway. This evaluation method can directly output the pressure relief effect conclusion, providing a scientific basis for optimizing and adjusting key parameters of the pressure relief project (such as borehole depth, drilling rate, and borehole spacing), and ensuring the implementation effect and safety of the pressure relief project.

[0168] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for analyzing and evaluating the pressure relief effect of borehole drilling, characterized in that, include: Step S100: Install a rope-type displacement acquisition device at the hydraulic drilling rig in the coal mine, and install a vibration signal acquisition device on the roadway side near the borehole. The rope-type displacement acquisition device records the displacement change data between the movable propulsion device and the fixed guide device at the front end of the guide rail of the hydraulic drilling rig in the coal mine, and the vibration signal acquisition device records the vibration change data of the borehole pressure relief project. Step S200: Based on the analysis of displacement change data and vibration change data, calculate the construction depth of the pressure relief borehole; Step S300: By statistically analyzing the drilling time and vibration amplitude at different drilling depths, the average amplitude per meter of depth is obtained; Step S400: Obtain the distribution of lateral support pressure in the roadway based on the average amplitude per meter depth; Step S500: Evaluate the borehole pressure relief effect by analyzing the distribution of lateral support pressure in the roadway; Step S200 includes: Step S201: Based on the significant amplitude clustering characteristics presented during the drilling process, perform feature identification and calculation on the vibration change data to generate preliminary drilling depth data; Step S202: Based on the differential pattern of displacement change rate, identify the operation stage of displacement change data to accurately distinguish between the drilling process and the retraction process; Step S203: Based on the results of the operation stage identification, the preliminary drilling depth data is corrected, the drilling withdrawal process is removed, and only the drilling process is retained. Through data verification and optimization calculation, the target drilling depth data is generated. Step S300 includes: The average amplitude per meter of depth is obtained by averaging the vibration amplitudes at different depths detected by the moving coil sensors located on the left and right sides of the pressure relief borehole. Step S400 further comprises: The distribution of lateral support pressure in the roadway is obtained based on the average amplitude per meter depth and the pre-established lateral support pressure inversion model. The method for establishing the lateral support pressure inversion model includes: Step A1: Obtain the average amplitude A of each amplitude cluster during single-hole drilling; Step A2: Obtain the lateral support stress σ during single-hole drilling; Step A3: Based on the average amplitude A and the lateral support stress σ, fit and establish the lateral support pressure inversion model; The lateral support pressure inversion model is a linear or nonlinear fitting model: Linear model: σ = aA + b, where a and b are fitting coefficients; Nonlinear model: σ = clnA + d, where c and d are fitting coefficients; Step S500 includes: When H>h Pmax When the drilling parameters and borehole depth reach the required level, it indicates that the drilling parameters and borehole depth have met the pressure relief technical requirements; otherwise, it indicates that the drilling parameters and borehole depth have not met the requirements and further adjustments to the drilling parameters or increases in drilling depth are needed. Here, H represents the actual drilling depth, and h is the actual drilling depth. Pmax This represents the borehole depth corresponding to the maximum lateral support pressure at the current drilling depth.

2. The method according to claim 1, characterized in that, In step S100, the cable-driven displacement acquisition device includes a portable drilling acquisition instrument and a cable-driven displacement sensor connected to the portable drilling acquisition instrument, and the vibration signal acquisition device includes a portable drilling acquisition instrument and a moving coil sensor connected to the portable drilling acquisition instrument.

3. The method according to claim 2, characterized in that, In step S100, the rope-type displacement acquisition device and the vibration signal acquisition device share a portable drilling acquisition instrument, and there are two moving coil sensors arranged on both sides of the borehole, which is a pressure relief borehole.

4. The method according to claim 1, characterized in that, h Pmax The lateral support pressure data were obtained by using a peak retrieval algorithm.

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