While-mining seismic exploration method and device

Abstract

The invention provides a while-mining seismic exploration method and device, and relates to the technical field of seismic exploration. The method comprises the following steps: acquiring a seismic wave signal; calculating a first travel time difference data set and a second travel time difference data set; grid division is carried out on the working face, the path length of each seismic wave signal passing through each grid is calculated, the path length of each grid, the first travel time difference data set and the second travel time difference data set are used as known quantities, and the slowness corresponding to each grid is solved by utilizing a tomography method; and performing speed imaging according to the slowness corresponding to each grid when the coal mining machine finishes cutting the working face once. The device executes the method. According to the while-mining seismic exploration method and device provided by the embodiment of the invention, the calculation complexity before while-mining seismic exploration can be reduced, the seismic imaging quality is improved, and efficient while-mining seismic exploration is facilitated.

Description

Technical Field

[0001] The present invention relates to the technical field of seismic exploration, and particularly relates to a seismic exploration method and device during mining. Background Art

[0002] Seismic exploration during mining is an advanced geophysical exploration technology, mainly used for real-time monitoring and evaluation of the underground resource mining process. This technology uses the vibration signal generated by the shearer cutting the coal wall as the seismic source, and synchronously receives signals in real time by arranging multiple geophones in the haulage roadway and the return airway. Based on the principle that the propagation speed of vibration waves is different in different media, it uses seismic exploration data real-time processing technology and tomography technology to realize the advanced detection of the structure in a certain area in front of the coal mine working face, providing a scientific basis and decision-making support for resource mining.

[0003] The core advantages of seismic exploration during mining lie in its safety and real-time performance. Traditional seismic exploration usually uses explosive seismic sources to collect static data before resource mining. However, this method is greatly affected by the control of explosive materials and cannot realize the real-time monitoring and early warning of dynamic geological disasters in coal mining. With the development of coal mining towards the intelligent direction, seismic exploration technology during mining has emerged as a safer, greener, and more economical seismic exploration technology.

[0004] When the existing geophysical exploration and drilling methods are used for advanced detection of the working face, after the coal seam working face advances a certain distance, the mining work of the working face is stopped. Then, the detection equipment is transported to the position where the current working face is located. Next, a certain range of advanced detection is carried out at this position through geophysical exploration and drilling methods. After the detection is completed, the mining work is resumed. Once beyond the detection limit, the shearer is stopped again and the above process is repeated. This detection method has cumbersome operation steps and requires continuous stopping of mining, greatly reducing the mining efficiency. To solve the above problems, this technology proposes a method for seismic detection during mining of the working face based on the shearer seismic source. First, sensors are arranged on the shearer drum and the hydraulic support. Then, the acquired seismic data is subjected to cross-correlation operation and interference processing. Finally, the seismic imaging method is directly used for real-time imaging of the working face, providing geological guarantee for intelligent coal mining.

[0005] This method selects to arrange sensors on the hydraulic support to obtain the vibration signal with the shearer as the seismic source. However, during the mining of the working face, the hydraulic support itself is constantly moving the support. At this time, the collected vibration signal contains the vibration of the equipment itself, which will greatly affect the computational complexity of subsequent signal processing and the quality of seismic imaging. In addition, the seismic imaging method has the problem of non-uniqueness, resulting in non-unique interpretation results.

[0006] Since the shearer is constantly moving and it generates a continuous signal, conventional data processing methods cannot be directly applied to the seismic data acquired during mining. To solve this problem, the prior art proposes a method for imaging the seismic data acquired during underground mining based on segmented waveform cross-correlation. The method segments the seismic data generated by the shearer, then uses the cross-correlation method to extract the travel times of the effective signals, and finally uses tomography to perform velocity imaging on the interior of the working face and in front of the cutting face and to locate the shearer seismic source position.

[0007] Based on the travel time differences extracted by segmented waveform cross-correlation between any two seismic waves, this method needs to invert the absolute travel times from the shearer seismic source to each geophone. This inversion process has extremely high computational complexity and cumulative errors will occur during the calculation process. Summary of the Invention

[0008] In view of the problems in the prior art, embodiments of the present invention provide a method and device for seismic exploration during mining, which can at least partially solve the problems existing in the prior art.

[0009] On the one hand, the present invention proposes a method for seismic exploration during mining, including:

[0010] During the process of the shearer cutting the working face, a seismic wave signal acquisition action is performed each time the shearer runs to a target position to obtain seismic wave signals;

[0011] From the seismic wave signals, a first vibration wave data set and a second vibration wave data set are respectively acquired through geophone groups corresponding to the haulage roadway and the return airway. The first target vibration wave data closest to the working face is selected from the first vibration wave data set, and a first travel time difference data set between each of the other vibration wave data in the first vibration wave data set and the first target vibration wave data is calculated; and the second target vibration wave data closest to the working face is selected from the second vibration wave data set, and a second travel time difference data set between each of the other vibration wave data in the second vibration wave data set and the second target vibration wave data is calculated;

[0012] The working face is divided into grids, and the path length of each seismic wave signal passing through each grid is calculated. Using the path length of each grid, the first travel time difference data set and the second travel time difference data set as known quantities, tomography is used to solve for the slowness corresponding to each grid, and velocity imaging is performed according to the slowness corresponding to each grid each time the shearer finishes cutting the working face.

[0013] Among them, the target positions include the head position of the working face, the middle position of the working face, and the tail position of the working face; correspondingly, during the process of the shearer cutting the working face, each time the shearer runs to a target position, a seismic wave signal acquisition action is performed to obtain seismic wave signals, including:

[0014] When the shearer runs to the head position of the working face, the first seismic wave signal acquisition action is performed, and the first seismic wave signal is obtained by continuously acquiring for a preset duration;

[0015] When the shearer runs to the middle position of the working face, the second seismic wave signal acquisition action is performed, and the second seismic wave signal is obtained by continuously acquiring for a preset duration;

[0016] When the shearer runs to the tail position of the working face, the third seismic wave signal acquisition action is performed, and the third seismic wave signal is obtained by continuously acquiring for a preset duration.

[0017] Among them, calculating the first travel time difference data set between other vibration wave data in the first vibration wave data group and the first target vibration wave data includes:

[0018] Traverse each other vibration wave data, and respectively use the fast Fourier transform to transform each other vibration wave data and the first target vibration wave data from the time domain to the frequency domain;

[0019] Multiply the spectrum of each other vibration wave data by the conjugate of the spectrum of the first target vibration wave data respectively to obtain the cross-power spectrum of every two signals;

[0020] Extract the phase spectrum from the cross-power spectrum of every two signals, and calculate the phase at each frequency point;

[0021] Perform unwrapping processing on the phase at each frequency point to obtain a continuously changing phase;

[0022] Determine the phase difference according to the continuously changing phase, and perform linear regression analysis on the frequency through the phase difference to obtain the first travel time difference data set composed of multiple travel time differences.

[0023] Among them, calculating the second travel time difference data set between other vibration wave data in the second vibration wave data group and the second target vibration wave data includes:

[0024] Traverse each other vibration wave data, and respectively use the fast Fourier transform to transform each other vibration wave data and the second target vibration wave data from the time domain to the frequency domain;

[0025] Multiply the spectrum of each other vibration wave data by the conjugate of the spectrum of the second target vibration wave data respectively to obtain the cross-power spectrum of every two signals;

[0026] Extract the phase spectrum from the cross-power spectrum of every two signals and calculate the phase at each frequency point;

[0027] Perform unwrapping processing on the phase at each frequency point to obtain a continuously varying phase;

[0028] Determine the phase difference based on the continuously varying phase, and perform linear regression analysis on the frequency through the phase difference to obtain a second travel-time difference dataset composed of multiple travel-time differences.

[0029] Among them, the calculation of the path length of each seismic wave signal passing through each grid includes:

[0030] Generate multiple rays starting from the position of the shearer as the seismic source and ending at the position of the geophone, and take the distance between the intersection points of each ray and the grid edges of the same grid as the path length of each grid.

[0031] Among them, after the step of obtaining the seismic wave signal is implemented, the goaf seismic exploration method further includes:

[0032] Preprocess the seismic wave signal.

[0033] On the one hand, the present invention proposes a goaf seismic exploration device including:

[0034] An acquisition unit, configured to perform a seismic wave signal acquisition action once whenever the shearer runs to a target position during the process of the shearer cutting the working face, so as to obtain a seismic wave signal;

[0035] A calculation unit, configured to obtain a first vibration wave data group and a second vibration wave data group from the seismic wave signal through detector groups respectively corresponding to the transportation roadway and the return airway, select the first target vibration wave data closest to the working face from the first vibration wave data group, and calculate a first travel-time difference dataset between each other vibration wave data in the first vibration wave data group and the first target vibration wave data; and select the second target vibration wave data closest to the working face from the second vibration wave data group, and calculate a second travel-time difference dataset between each other vibration wave data in the second vibration wave data group and the second target vibration wave data;

[0036] An imaging unit, configured to divide the working face into grids, calculate the path length of each seismic wave signal passing through each grid, take the path length of each grid, the first travel-time difference dataset and the second travel-time difference dataset as known quantities, and use the tomography method to solve for the slowness corresponding to each grid, and perform velocity imaging according to the slowness corresponding to each grid whenever the shearer finishes cutting the working face once.

[0037] In another aspect, an embodiment of the present invention provides a computer device, including a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the computer program, the following method is implemented:

[0038] During the process of the shearer cutting the working face, a seismic wave signal acquisition action is performed every time the shearer runs to the target position to obtain seismic wave signals.

[0039] A first vibration wave data set and a second vibration wave data set are acquired from the seismic wave signals through detector groups corresponding to the transportation roadway and the return airway respectively. The first target vibration wave data closest to the working face is selected from the first vibration wave data set, and a first travel time difference data set between each of the other vibration wave data in the first vibration wave data set and the first target vibration wave data is calculated; and the second target vibration wave data closest to the working face is selected from the second vibration wave data set, and a second travel time difference data set between each of the other vibration wave data in the second vibration wave data set and the second target vibration wave data is calculated.

[0040] The working face is divided into grids, and the path length of each seismic wave signal passing through each grid is calculated. Using the path length of each grid, the first travel time difference data set, and the second travel time difference data set as known quantities, the slowness corresponding to each grid is obtained by using the tomographic imaging method, and velocity imaging is performed according to the slowness corresponding to each grid every time the shearer finishes cutting the working face.

[0041] An embodiment of the present invention provides a computer-readable storage medium, including:

[0042] The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the following method is implemented:

[0043] During the process of the shearer cutting the working face, a seismic wave signal acquisition action is performed every time the shearer runs to the target position to obtain seismic wave signals.

[0044] A first vibration wave data set and a second vibration wave data set are acquired from the seismic wave signals through detector groups corresponding to the transportation roadway and the return airway respectively. The first target vibration wave data closest to the working face is selected from the first vibration wave data set, and a first travel time difference data set between each of the other vibration wave data in the first vibration wave data set and the first target vibration wave data is calculated; and the second target vibration wave data closest to the working face is selected from the second vibration wave data set, and a second travel time difference data set between each of the other vibration wave data in the second vibration wave data set and the second target vibration wave data is calculated.

[0045] The working face is meshed, and the path length of each seismic wave signal passing through each grid is calculated. Using the path length of each grid, the first travel time difference data set and the second travel time difference data set as known quantities, and the slowness corresponding to each grid is solved by using the tomography method. Whenever the shearer cuts the working face once, velocity imaging is performed according to the slowness corresponding to each grid.

[0046] An embodiment of the present invention also provides a computer program product. The computer program product includes a computer program, and when the computer program is executed by a processor, the following method is implemented:

[0047] During the process of the shearer cutting the working face, a seismic wave signal acquisition action is performed whenever the shearer runs to the target position to obtain the seismic wave signal;

[0048] The first vibration wave data set and the second vibration wave data set are acquired from the seismic wave signal through the detector groups corresponding to the transportation roadway and the return airway respectively. The first target vibration wave data closest to the working face is selected from the first vibration wave data set, and the first travel time difference data set between each other vibration wave data in the first vibration wave data set and the first target vibration wave data is calculated; and the second target vibration wave data closest to the working face is selected from the second vibration wave data set, and the second travel time difference data set between each other vibration wave data in the second vibration wave data set and the second target vibration wave data is calculated;

[0049] The working face is meshed, and the path length of each seismic wave signal passing through each grid is calculated. Using the path length of each grid, the first travel time difference data set and the second travel time difference data set as known quantities, and the slowness corresponding to each grid is solved by using the tomography method. Whenever the shearer cuts the working face once, velocity imaging is performed according to the slowness corresponding to each grid.

[0050] The seismic exploration method and device provided by the embodiments of the present invention perform a seismic wave signal acquisition action every time the shearer runs to a target position during the process of the shearer cutting the working face, so as to obtain seismic wave signals; the first vibration wave data set and the second vibration wave data set are obtained from the seismic wave signals through the detector groups respectively corresponding to the transportation roadway and the return airway, the first target vibration wave data closest to the working face is selected from the first vibration wave data set, and the first travel time difference data set between each of the other vibration wave data in the first vibration wave data set and the first target vibration wave data is calculated; and the second target vibration wave data closest to the working face is selected from the second vibration wave data set, and the second travel time difference data set between each of the other vibration wave data in the second vibration wave data set and the second target vibration wave data is calculated; the working face is divided into grids, the path length of each seismic wave signal passing through each grid is calculated, the path length of each grid, the first travel time difference data set and the second travel time difference data set are used as known quantities, and the slowness corresponding to each grid is obtained by using the tomography method. Every time the shearer finishes cutting the working face once, velocity imaging is performed according to the slowness corresponding to each grid, which can reduce the calculation complexity before the seismic exploration during mining and improve the seismic imaging quality, and is helpful for the efficient seismic exploration during mining. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts. In the drawings:

[0052] Figure 1 is a schematic flow chart of the seismic exploration method during mining provided by an embodiment of the present invention.

[0053] Figure 2 is a schematic diagram for explaining the installation position of the detectors provided by the embodiments of the present invention.

[0054] Figure 3 is a schematic flow chart of the seismic exploration method during mining provided by another embodiment of the present invention.

[0055] Figure 4 is a schematic diagram for explaining the calculation of the path length in the grid provided by the embodiments of the present invention.

[0056] Figure 5 is a schematic diagram for explaining the slowness corresponding to each grid calculated by iterative calculation using the SIRT algorithm provided by the embodiments of the present invention.

[0057] Figure 6It is a schematic structural diagram of a seismic exploration device during mining provided by an embodiment of the present invention.

[0058] Figure 7 It is a schematic entity structure diagram of a computer device provided by an embodiment of the present invention. Detailed implementation manners

[0059] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer and more understandable, the following further describes the embodiments of the present invention in detail with reference to the accompanying drawings. Herein, the illustrative embodiments of the present invention and their descriptions are used to explain the present invention, but not to limit the present invention. It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be arbitrarily combined with each other.

[0060] Figure 1 It is a schematic flow diagram of a seismic exploration method during mining provided by an embodiment of the present invention. As Figure 1 shown, the seismic exploration method during mining provided by the embodiment of the present invention includes:

[0061] Step S1: During the process of the shearer cutting the working face, a seismic wave signal acquisition action is performed each time the shearer runs to the target position to obtain seismic wave signals.

[0062] Step S2: Obtain a first vibration wave data set and a second vibration wave data set from the seismic wave signals through detector groups corresponding to the haulage roadway and the return airway respectively. Select the first target vibration wave data closest to the working face from the first vibration wave data set, and calculate a first travel time difference data set between each of the other vibration wave data in the first vibration wave data set and the first target vibration wave data; and select the second target vibration wave data closest to the working face from the second vibration wave data set, and calculate a second travel time difference data set between each of the other vibration wave data in the second vibration wave data set and the second target vibration wave data.

[0063] Step S3: Divide the working face into grids, calculate the path length of each seismic wave signal passing through each grid. Taking the path length of each grid, the first travel time difference data set and the second travel time difference data set as known quantities, and using the tomography method to solve for the slowness corresponding to each grid. Each time the shearer finishes cutting the working face, velocity imaging is performed according to the slowness corresponding to each grid.

[0064] In the above step S1, the device performs an earthquake wave signal acquisition operation once every time the shearer runs to the target position during the cutting face process of the shearer, so as to obtain the earthquake wave signal. The device may be a computer device that executes this method. In the technical solution of this application, the acquisition, storage, use, processing, etc. of data all comply with relevant regulations. Before executing the method of the present invention, first deploy geophones (detectors) and acquisition sub-stations (computer devices for collecting data), such as Figure 2 as shown

[0065] The specific description is as follows:

[0066] A plurality of equally spaced three-axis geophones are arranged in a row on the coal walls of the transportation roadway and the return airway close to the working face. Taking the cutting-eye direction as the X-axis, the coal-mining direction as the Y-axis, and the vertical direction from the floor to the roof as the Z-axis. Then, the acquisition sub-station is connected to the geophones to collect vibration waves. The vibration waves are generated by the coal-cutting action of the shearer and propagated through the working face, and the signals are transmitted to the computer device in real time through the underground ring network.

[0067] The target positions include the head position of the working face, the middle position of the working face, and the tail position of the working face; correspondingly, the step of performing an earthquake wave signal acquisition operation once every time the shearer runs to the target position during the cutting face process of the shearer to obtain the earthquake wave signal includes:

[0068] When the shearer runs to the head position of the working face, perform the first earthquake wave signal acquisition operation and continuously acquire the first earthquake wave signal for a preset duration;

[0069] When the shearer runs to the middle position of the working face, perform the second earthquake wave signal acquisition operation and continuously acquire the second earthquake wave signal for a preset duration;

[0070] When the shearer runs to the tail position of the working face, perform the third earthquake wave signal acquisition operation and continuously acquire the third earthquake wave signal for a preset duration. It should be noted that the three earthquake wave signal acquisitions are all triggered when the shearer runs to the target position, and the preset durations are all the same value, so as to ensure synchronous trigger type acquisition of vibration waves. The preset duration can be set independently according to the actual situation, and can be selected as 10S.

[0071] The method of the present invention uses synchronous trigger type to acquire vibration waves. Different from conventional seismic exploration, the seismic source of seismic while mining is continuous in time and constantly changing in spatial position. Therefore, conventional imaging methods are not applicable to this scenario. To solve this problem, the method of the present invention uses a trigger type to collect signals.

[0072] The specific method is as follows: on the premise of the known position of the shearer, during the process of the shearer completely cutting the working face once, when the shearer runs to the head position of the working face (such as the position of the 6# support), the middle position of the working face (such as the position of the 80# support), and the tail position of the working face (such as the position of the 160# support), vibration waves are synchronously collected for 10 s respectively. Since the running speed of the shearer is slow during operation and the single data acquisition time is short, the vibration wave data of these three sections can be used as the single seismic source records of the above three positions.

[0073] As Figure 3 shown, after the step of obtaining the seismic wave signal, the seismic exploration method during mining further includes:

[0074] Preprocessing the seismic wave signal. The subsequent method steps can be executed using the preprocessed seismic wave signal. The preprocessing can specifically include:

[0075] (1) Bad trace removal operation.

[0076] (2) Using filtering technology to remove environmental noise.

[0077] (3) Performing amplitude correction to compensate for the energy attenuation during the propagation of seismic waves.

[0078] (4) Using deconvolution interference to improve the signal resolution of seismic waves.

[0079] (5) Performing amplitude normalization to make the energy of seismic wave data of each trace balanced.

[0080] In the above step S2, the device obtains a first vibration wave data group and a second vibration wave data group from the seismic wave signal through the geophone groups corresponding to the transportation roadway and the return airway respectively, selects the first target vibration wave data closest to the working face from the first vibration wave data group, and calculates the first travel time difference data set between each other vibration wave data in the first vibration wave data group and the first target vibration wave data; and selects the second target vibration wave data closest to the working face from the second vibration wave data group, and calculates the second travel time difference data set between each other vibration wave data in the second vibration wave data group and the second target vibration wave data. As Figure 2 shown, the first vibration wave data group is the vibration wave data detected by the upper row of geophones, and the second vibration wave data group is the vibration wave data detected by the lower row of geophones.

[0081] Taking the first vibration wave data group as an example (the second vibration wave data group will not be elaborated), as Figure 2 shown, the first target vibration wave data is the first geophone in the upper left corner.

[0082] Calculating a first set of travel time differences between each of the other vibration wave data in the first vibration wave data set and the first target vibration wave data includes:

[0083] Traverse each piece of other vibration wave data, and respectively use the fast Fourier transform to transform each piece of other vibration wave data and the first target vibration wave data from the time domain to the frequency domain;

[0084] Multiply the spectrum of each piece of other vibration wave data by the conjugate of the spectrum of the first target vibration wave data respectively to obtain the cross-power spectrum of every two signals;

[0085] Extract the phase spectrum from the cross-power spectrum of every two signals, and calculate the phase at each frequency point;

[0086] Perform unwrapping processing on the phase at each frequency point to obtain a continuously varying phase;

[0087] Determine the phase difference according to the continuously varying phase, and perform linear regression analysis on the frequency through the phase difference to obtain a first set of travel time differences composed of multiple travel time differences.

[0088] Since the source of the seismic data acquired during mining is continuous in time, it is difficult to obtain the specific earthquake occurrence time for each vibration wave. To avoid this problem, the method of the present invention fixes the source position, and respectively uses the vibration wave data collected from the transportation roadway and the return airway as the same group of data. In each group of data, the data collected by the geophone closest to the working face is used as the reference channel, and the phase spectrum is calculated in turn with the signals collected by other geophones in the same group of data, so as to obtain the relative travel time between the source and each geophone and the source and the first geophone. The steps of calculating the travel time difference between the i-th channel and the first channel signals using the phase spectrum method are as follows:

[0089] 1) Use the fast Fourier transform to transform the two signals from the time domain to the frequency domain;

[0090] 2) Multiply the spectrum of the i-th channel signal by the conjugate of the spectrum of the first channel signal to obtain the cross-power spectrum of the two signals;

[0091] 3) Extract the phase spectrum from the cross-power spectrum, and calculate the phase at each frequency point;

[0092] 4) Perform unwrapping processing on the phase to obtain a continuously varying phase;

[0093] 5) Determine the phase difference according to the continuously varying phase, and perform linear regression analysis on the frequency through the phase difference to obtain a set of travel time differences composed of multiple travel time differences.

[0094] In the above step S3, the device divides the working face into grids, calculates the path length of each seismic wave signal passing through each grid, takes the path length of each grid, the first travel time difference dataset, and the second travel time difference dataset as known quantities, and uses the tomography method to solve for the slowness corresponding to each grid. Whenever the shearer cuts the working face once, velocity imaging is performed according to the slowness corresponding to each grid. The calculation of the path length of each seismic wave signal passing through each grid includes:

[0095] Taking the position of the shearer as the seismic source as the starting point and the position of the geophone as the end point, multiple rays are generated, and the distance between the intersection points of each ray and the grid edges of the same grid is used as the path length of each grid.

[0096] The working face area to be detected is divided into grids (for example, the grid side length is 1 meter), and the path length of each seismic wave passing through each grid is calculated. The specific method here is as follows: Select one of the seismic wave data. First, calculate the slope of the straight line according to the source position M(x0, y0) and the geophone position N(x1, y1). Then use the Bresenham algorithm to determine the grids passed by the straight line. Next, for each grid, calculate the intersection points of the straight line and the grid boundaries. Finally, calculate the length of the line segment in each grid according to the coordinates of the intersection points of the straight line and the grid, as Figure 4 shown.

[0097] The tomography method can be selected as the SIRT algorithm, and the SIRT algorithm is used to iteratively calculate the slowness corresponding to each grid, as Figure 5 shown.

[0098] As Figure 5 shown, M is the position of the shearer seismic source, N1 is the position of geophone 1, N2 is the position of geophone 2 (N1 and N2 are in the same group of geophones), s j represents the slowness corresponding to the jth grid, and t i represents the absolute travel time of the ith seismic wave. Then for the first seismic wave, there is:

[0099] t1 = 0·s1 + 0·s2 + 0·s3 + l 1,4 ·s4 + l 1,5 ·s5 + 0·s6 + 0·s7 + l 1,8 ·s8 + l 1,9 ·s9

[0100] For the second seismic wave, there is:

[0101] t2 = 0·s1 + 0·s2 + 0·s3 + l 2,4 ·s4 + 0·s5 + 0·s6 + 0·s7 + l 2,8 ·s8 + 0·s9

[0102] Subtract the expression corresponding to the first seismic wave from the expression corresponding to the second seismic wave to obtain the travel time difference expression as follows:

[0103] Δt 1,2 = 0·s1 + 0·s2 + 0·s3 + (l 1,4 - l 2,4 )·s4 + (l 1,5 - 0)·s5 + 0·s6 + 0·s7 + (l 1,8 - l 2,8 )·s8 + (l 1,9 - 0)·s9

[0104] The travel time difference Δt between the two seismic waves 1,2 Can be obtained from the above first travel time difference dataset and the second travel time difference dataset, and each l is obtained from the path length of each grid above. In the actual application scenario of seismic exploration during production, when the number of seismic sources and the number of geophones are large enough, a travel time difference expression similar to the above can be obtained between every two seismic waves, and finally a linear equation system with s j As the unknown quantity is formed. To solve this linear equation system, the algorithm used in the method of the present invention is the SIRT algorithm, and its specific implementation steps are as follows:

[0105] 1) Given a set of initial values Where J is the number of grids.

[0106] 2) Calculate the estimated value Where I is the total number of seismic waves and k is the number of iterations.

[0107] 3) Calculate the observed value Δt i,j (i = 1, 2, L I) and the estimated value r i (k) If the difference does not meet the predetermined error requirement, then perform the subsequent steps.

[0108] 4) Calculate the average revised value within the jth grid Assume that there are M j Seismic waves passing through the grid, then:

[0109] 5) Correct the slowness of the jth grid And according to acoustic logging or other geophysical data for To be constrained: That is:

[0110]

[0111] 6) Determine whether the difference after iteration meets the predetermined error requirement. If it does, stop. If not, proceed to the next round of iteration (for k+1). Finally, the slowness s of all grids that meet the requirements is obtained. j .

[0112] Each time the coal mining machine completely cuts a working face, the slowness s corresponding to each grid output by the algorithm can be calculated. j The speed imaging is performed, which is an existing conventional method and will not be described in detail.

[0113] This enables simultaneous exploration of a certain area in front of the mining face in underground coal mines.

[0114] The seismic exploration method provided by the embodiment of the present invention has the following beneficial technical effects:

[0115] By integrating multi-channel synchronous acquisition technology, real-time processing technology of seismic data, computational geometry technology and travel-time tomography algorithm, it is possible to conduct advance detection of the structure of a certain area in front of the underground coal mine recovery working face, thereby providing data support for the geological transparency of the coal mining working face and intelligent mining.

[0116] The method of the present invention takes the seismic signals collected in the transport lane and the return air lane with the coal mining machine as the source as the research object, focuses on the characteristics and needs of the seismic exploration problems during mining, and takes the improvement of high-precision real-time imaging of the complex geological environment in the coal mine as the core goal. Based on the principle that the propagation speed of vibration waves in different media is different, the method collects the seismic wave data generated by the coal mining machine cutting coal synchronously in two lanes through triggered multi-channel synchronous acquisition and data preprocessing, and then uses the phase spectrum method to calculate the travel time difference between each two seismic wave signals on this basis, and then the unmined working face is gridded and the slowness corresponding to each grid is iteratively calculated based on the Bresenham algorithm and SIRT algorithm, and finally the velocity imaging is performed to achieve the exploration goal, providing geological guarantee for intelligent mining of coal mines.

[0117] The seismic exploration method during mining provided by the embodiment of the present invention performs a seismic wave signal acquisition action once whenever the shearer runs to the target position during the cutting process of the shearer working face, so as to obtain seismic wave signals; the first vibration wave data set and the second vibration wave data set are obtained from the seismic wave signals through the detector groups corresponding to the transportation roadway and the return airway respectively, the first target vibration wave data closest to the working face is selected from the first vibration wave data set, and the first travel time difference data set between each of the other vibration wave data in the first vibration wave data set and the first target vibration wave data is calculated; and the second target vibration wave data closest to the working face is selected from the second vibration wave data set, and the second travel time difference data set between each of the other vibration wave data in the second vibration wave data set and the second target vibration wave data is calculated; the working face is divided into grids, the path length of each seismic wave signal passing through each grid is calculated, the path length of each grid, the first travel time difference data set and the second travel time difference data set are used as known quantities, and the slowness corresponding to each grid is obtained by using the tomography method. Whenever the shearer finishes cutting the working face once, velocity imaging is performed according to the slowness corresponding to each grid, which can reduce the computational complexity before the seismic exploration during mining and improve the seismic imaging quality, and is helpful for efficient seismic exploration during mining.

[0118] Further, the target positions include the head position of the working face, the middle position of the working face, and the tail position of the working face; correspondingly, the performing a seismic wave signal acquisition action once whenever the shearer runs to the target position during the cutting process of the shearer working face to obtain seismic wave signals includes:

[0119] When the shearer runs to the head position of the working face, the first seismic wave signal acquisition action is performed, and the first seismic wave signal is obtained by continuously acquiring for a preset duration; the description can refer to the above embodiment and will not be repeated.

[0120] When the shearer runs to the middle position of the working face, the second seismic wave signal acquisition action is performed, and the second seismic wave signal is obtained by continuously acquiring for a preset duration; the description can refer to the above embodiment and will not be repeated.

[0121] When the shearer runs to the tail position of the working face, the third seismic wave signal acquisition action is performed, and the third seismic wave signal is obtained by continuously acquiring for a preset duration. The description can refer to the above embodiment and will not be repeated.

[0122] Further, the calculating the first travel time difference data set between each of the other vibration wave data in the first vibration wave data set and the first target vibration wave data includes:

[0123] Traverse each other vibration wave data, and respectively use the fast Fourier transform to transform each other vibration wave data and the first target vibration wave data from the time domain to the frequency domain; refer to the above embodiments for description and will not be elaborated here.

[0124] Multiply the spectrum of each other vibration wave data by the conjugate of the spectrum of the first target vibration wave data respectively to obtain the cross-power spectrum of every two signals; refer to the above embodiments for description and will not be elaborated here.

[0125] Extract the phase spectrum from the cross-power spectrum of every two signals, and calculate the phase at each frequency point; refer to the above embodiments for description and will not be elaborated here.

[0126] Perform unwrapping processing on the phase at each frequency point to obtain a continuously changing phase; refer to the above embodiments for description and will not be elaborated here.

[0127] Determine the phase difference according to the continuously changing phase, and perform linear regression analysis on the frequency through the phase difference to obtain a first travel-time difference data set composed of multiple travel-time differences; refer to the above embodiments for description and will not be elaborated here.

[0128] Further, the calculation of the second travel-time difference data set between the other vibration wave data in the second vibration wave data group and the second target vibration wave data includes:

[0129] Traverse each other vibration wave data, and respectively use the fast Fourier transform to transform each other vibration wave data and the second target vibration wave data from the time domain to the frequency domain; refer to the above embodiments for description and will not be elaborated here.

[0130] Multiply the spectrum of each other vibration wave data by the conjugate of the spectrum of the second target vibration wave data respectively to obtain the cross-power spectrum of every two signals; refer to the above embodiments for description and will not be elaborated here.

[0131] Extract the phase spectrum from the cross-power spectrum of every two signals, and calculate the phase at each frequency point; refer to the above embodiments for description and will not be elaborated here.

[0132] Perform unwrapping processing on the phase at each frequency point to obtain a continuously changing phase; refer to the above embodiments for description and will not be elaborated here.

[0133] Determine the phase difference according to the continuously changing phase, and perform linear regression analysis on the frequency through the phase difference to obtain a second travel-time difference data set composed of multiple travel-time differences; refer to the above embodiments for description and will not be elaborated here.

[0134] Further, the calculation of the path length of each seismic wave signal passing through each grid includes:

[0135] Taking the position of the shearer as the seismic source as the starting point and the position of the geophone as the end point, multiple rays are generated. The distance between the intersection points of each ray and the grid edges of the same grid is used as the path length of each grid. Refer to the above embodiments for description and details will not be repeated.

[0136] Further, after the step of realizing the acquisition of seismic wave signals, the seismic exploration method during coal mining further includes:

[0137] Preprocessing the seismic wave signals. Refer to the above embodiments for description and details will not be repeated.

[0138] Figure 6 It is a schematic structural diagram of a seismic exploration device during coal mining provided by an embodiment of the present invention. As Figure 6 shown, the seismic exploration device during coal mining provided by the embodiment of the present invention includes an acquisition unit 601, a calculation unit 602, and an imaging unit 603, wherein:

[0139] The acquisition unit 601 is configured to perform a seismic wave signal acquisition operation once whenever the shearer runs to a target position during the process of the shearer cutting the working face, so as to realize the acquisition of seismic wave signals; the calculation unit 602 is configured to obtain a first vibration wave data set and a second vibration wave data set from the seismic wave signals through geophone groups corresponding to the transportation roadway and the return airway respectively, select the first target vibration wave data closest to the working face from the first vibration wave data set, and calculate a first travel time difference data set between each of the other vibration wave data in the first vibration wave data set and the first target vibration wave data; and select the second target vibration wave data closest to the working face from the second vibration wave data set, and calculate a second travel time difference data set between each of the other vibration wave data in the second vibration wave data set and the second target vibration wave data; the imaging unit 603 is configured to divide the working face into grids, calculate the path length of each seismic wave signal passing through each grid, use the path length of each grid, the first travel time difference data set, and the second travel time difference data set as known quantities, and use the tomography method to solve for the slowness corresponding to each grid, and perform velocity imaging according to the slowness corresponding to each grid whenever the shearer finishes cutting the working face once.

[0140] Specifically, the acquisition unit 601 in the device is configured to perform an earthquake wave signal acquisition operation each time the shearer runs to a target position during the process of the shearer cutting the working face, so as to acquire earthquake wave signals; the calculation unit 602 is configured to obtain a first vibration wave data set and a second vibration wave data set from the acquired earthquake wave signals through detector groups respectively corresponding to the transportation roadway and the return airway, select first target vibration wave data closest to the working face from the first vibration wave data set, and calculate a first travel time difference data set between each of the other vibration wave data in the first vibration wave data set and the first target vibration wave data; and select second target vibration wave data closest to the working face from the second vibration wave data set, and calculate a second travel time difference data set between each of the other vibration wave data in the second vibration wave data set and the second target vibration wave data; the imaging unit 603 is configured to divide the working face into grids, calculate the path length of each earthquake wave signal passing through each grid, use the path length of each grid, the first travel time difference data set, and the second travel time difference data set as known quantities, and use the tomography method to solve for the slowness corresponding to each grid, and perform velocity imaging according to the slowness corresponding to each grid each time the shearer finishes cutting the working face.

[0141] The real-time seismic exploration device provided by the embodiment of the present invention performs an earthquake wave signal acquisition operation each time the shearer runs to a target position during the process of the shearer cutting the working face, so as to acquire earthquake wave signals; obtains a first vibration wave data set and a second vibration wave data set from the acquired earthquake wave signals through detector groups respectively corresponding to the transportation roadway and the return airway, selects first target vibration wave data closest to the working face from the first vibration wave data set, and calculates a first travel time difference data set between each of the other vibration wave data in the first vibration wave data set and the first target vibration wave data; and selects second target vibration wave data closest to the working face from the second vibration wave data set, and calculates a second travel time difference data set between each of the other vibration wave data in the second vibration wave data set and the second target vibration wave data; divides the working face into grids, calculates the path length of each earthquake wave signal passing through each grid, uses the path length of each grid, the first travel time difference data set, and the second travel time difference data set as known quantities, and uses the tomography method to solve for the slowness corresponding to each grid, and performs velocity imaging according to the slowness corresponding to each grid each time the shearer finishes cutting the working face, which can reduce the computational complexity before real-time seismic exploration and improve the seismic imaging quality, and contribute to efficient real-time seismic exploration.

[0142] The embodiment of the real-time seismic exploration device provided by the embodiment of the present invention can specifically be used to execute the processing procedures of the above method embodiments, and its functions will not be elaborated here. For details, reference can be made to the detailed descriptions of the above method embodiments.

[0143] Figure 7 This is a schematic diagram of the physical structure of the computer device provided by the embodiment of the present invention. As Figure 7 shown, the computer device includes: a memory 701, a processor 702, and a computer program stored on the memory 701 and executable on the processor 702. When the processor 702 executes the computer program, the following method is implemented:

[0144] During the process of the shearer cutting the working face, a seismic wave signal acquisition action is performed each time the shearer runs to the target position to obtain seismic wave signals;

[0145] A first vibration wave data set and a second vibration wave data set are acquired from the seismic wave signals through detector groups corresponding to the transportation roadway and the return airway respectively. The first target vibration wave data closest to the working face is selected from the first vibration wave data set, and a first travel time difference data set between each of the other vibration wave data in the first vibration wave data set and the first target vibration wave data is calculated; and the second target vibration wave data closest to the working face is selected from the second vibration wave data set, and a second travel time difference data set between each of the other vibration wave data in the second vibration wave data set and the second target vibration wave data is calculated;

[0146] The working face is divided into grids, and the path length of each seismic wave signal passing through each grid is calculated. Using the path length of each grid, the first travel time difference data set, and the second travel time difference data set as known quantities, the slowness corresponding to each grid is obtained by using the tomography method, and velocity imaging is performed according to the slowness corresponding to each grid each time the shearer finishes cutting the working face.

[0147] This embodiment discloses a computer program product. The computer program product includes a computer program. When the computer program is executed by a processor, the following method is implemented:

[0148] During the process of the shearer cutting the working face, a seismic wave signal acquisition action is performed each time the shearer runs to the target position to obtain seismic wave signals;

[0149] The first vibration wave data set and the second vibration wave data set are acquired from the seismic wave signals by detector groups corresponding to the transportation roadway and the return airway respectively. The first target vibration wave data closest to the working face is selected from the first vibration wave data set, and a first travel time difference data set between each of the other vibration wave data in the first vibration wave data set and the first target vibration wave data is calculated; and the second target vibration wave data closest to the working face is selected from the second vibration wave data set, and a second travel time difference data set between each of the other vibration wave data in the second vibration wave data set and the second target vibration wave data is calculated.

[0150] The working face is divided into grids, and the path length of each seismic wave signal passing through each grid is calculated. Using the path length of each grid, the first travel time difference data set and the second travel time difference data set as known quantities, the slowness corresponding to each grid is solved by using the tomography method, and velocity imaging is performed according to the slowness corresponding to each grid whenever the shearer finishes cutting the working face once.

[0151] This embodiment provides a computer-readable storage medium storing a computer program, and when the computer program is executed by a processor, the following method is implemented:

[0152] During the process of the shearer cutting the working face, a seismic wave signal acquisition action is performed each time the shearer runs to a target position to obtain seismic wave signals.

[0153] The first vibration wave data set and the second vibration wave data set are acquired from the seismic wave signals by detector groups corresponding to the transportation roadway and the return airway respectively. The first target vibration wave data closest to the working face is selected from the first vibration wave data set, and a first travel time difference data set between each of the other vibration wave data in the first vibration wave data set and the first target vibration wave data is calculated; and the second target vibration wave data closest to the working face is selected from the second vibration wave data set, and a second travel time difference data set between each of the other vibration wave data in the second vibration wave data set and the second target vibration wave data is calculated.

[0154] The working face is divided into grids, and the path length of each seismic wave signal passing through each grid is calculated. Using the path length of each grid, the first travel time difference data set and the second travel time difference data set as known quantities, the slowness corresponding to each grid is solved by using the tomography method, and velocity imaging is performed according to the slowness corresponding to each grid whenever the shearer finishes cutting the working face once.

[0155] Compared with the technical solutions in the prior art, in the embodiment of the present invention, the seismic prospecting method during mining executes a seismic wave signal acquisition action each time the shearer runs to the target position during the process of the shearer cutting the working face, so as to obtain seismic wave signals; the first vibration wave data set and the second vibration wave data set are acquired from the seismic wave signals through the detector groups corresponding to the transportation roadway and the return airway respectively, the first target vibration wave data closest to the working face is selected from the first vibration wave data set, and the first travel time difference data set between each other vibration wave data in the first vibration wave data set and the first target vibration wave data is calculated; and the second target vibration wave data closest to the working face is selected from the second vibration wave data set, and the second travel time difference data set between each other vibration wave data in the second vibration wave data set and the second target vibration wave data is calculated; the working face is divided into grids, the path length of each seismic wave signal passing through each grid is calculated, the path length of each grid, the first travel time difference data set and the second travel time difference data set are used as known quantities, and the slowness corresponding to each grid is obtained by using the tomography method. Each time the shearer finishes cutting the working face, velocity imaging is performed according to the slowness corresponding to each grid, which can reduce the calculation complexity before the seismic prospecting during mining and improve the seismic imaging quality, and is helpful for efficient seismic prospecting during mining.

[0156] Those skilled in the art should understand that the embodiments of the present invention may be provided as a method, a system, or a computer program product. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0157] The present invention is described with reference to the flowcharts and / or block diagrams of methods, apparatuses (systems), and computer program products according to embodiments of the present invention. It should be understood that each flow and / or block in the flowchart and / or block diagram, and the combination of flows and / or blocks in the flowchart and / or block diagram, can be realized by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices generate a device for realizing the functions specified in Figure 1 one or more of the processes or multiple processes and / or blocks Figure 1 one or more of the blocks or multiple blocks.

[0158] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to operate in a particular manner, such that the instructions stored in the computer-readable memory produce a manufacture including an instruction device that implements the functions specified in one or more of the processes and / or blocks Figure 1 of one or more of the processes and / or blocks Figure 1 specified in the one or more of the processes and / or blocks.

[0159] These computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process, whereby the instructions executed on the computer or other programmable apparatus provide steps for implementing the functions specified in one or more of the processes and / or blocks Figure 1 of one or more of the processes and / or blocks Figure 1 specified in the one or more of the processes and / or blocks.

[0160] In the description of the present specification, descriptions with reference to terms such as "one embodiment", "a specific embodiment", "some embodiments", "for example", "example", "specific example", or "some examples", etc., mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In the present specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0161] The above-described specific embodiments have further elaborated on the object, technical solution, and beneficial effects of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not used to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A seismic exploration method during mining, characterized in that, Including: During the process of the shearer cutting the working face, each time the shearer runs to the target position, a seismic wave signal acquisition action is executed to obtain the seismic wave signal; The first vibration wave data set and the second vibration wave data set are obtained from the seismic wave signal through the detector groups corresponding to the haulage roadway and the return airway respectively. The first target vibration wave data closest to the working face is selected from the first vibration wave data set, and the first travel time difference data set between each other vibration wave data in the first vibration wave data set and the first target vibration wave data is calculated; and the second target vibration wave data closest to the working face is selected from the second vibration wave data set, and the second travel time difference data set between each other vibration wave data in the second vibration wave data set and the second target vibration wave data is calculated; The working face is divided into grids, and the path length of each seismic wave signal passing through each grid is calculated. Taking the path length of each grid, the first travel time difference data set and the second travel time difference data set as known quantities, and using the tomography method to solve the slowness corresponding to each grid. Each time the shearer finishes cutting the working face, velocity imaging is performed according to the slowness corresponding to each grid.

2. The seismic exploration method for mining according to claim 1, characterized in that, The target positions include the head position of the working face, the middle position of the working face, and the tail position of the working face; correspondingly, the step of, during the process of the shearer cutting the working face, each time the shearer runs to the target position, a seismic wave signal acquisition action is executed to obtain the seismic wave signal, includes: When the shearer runs to the head position of the working face, the first seismic wave signal acquisition action is executed, and the first seismic wave signal is obtained continuously for a preset duration; When the shearer runs to the middle position of the working face, the second seismic wave signal acquisition action is executed, and the second seismic wave signal is obtained continuously for a preset duration; When the shearer runs to the tail position of the working face, the third seismic wave signal acquisition action is executed, and the third seismic wave signal is obtained continuously for a preset duration.

3. The seismic exploration method during mining according to claim 1, wherein The step of calculating the first travel time difference data set between each other vibration wave data in the first vibration wave data set and the first target vibration wave data includes: Traverse each other vibration wave data, and respectively use the fast Fourier transform to transform each other vibration wave data and the first target vibration wave data from the time domain to the frequency domain; Multiply the spectrum of each other vibration wave data by the conjugate of the spectrum of the first target vibration wave data respectively to obtain the cross-power spectrum of each two signals; Extract the phase spectrum from the cross-power spectrum of each two signals, and calculate the phase at each frequency point; Perform unwrapping processing on the phase at each frequency point to obtain a continuously changing phase; Determine the phase difference according to the continuously changing phase, and perform linear regression analysis on the frequency through the phase difference to obtain the first travel time difference data set composed of multiple travel time differences.

4. The seismic exploration method during mining according to claim 1, wherein The step of calculating the second travel time difference data set between each other vibration wave data in the second vibration wave data set and the second target vibration wave data includes: Traverse each other vibration wave data, and respectively use the fast Fourier transform to transform each other vibration wave data and the second target vibration wave data from the time domain to the frequency domain; Multiply the spectrum of each other vibration wave data by the conjugate of the spectrum of the second target vibration wave data respectively to obtain the cross-power spectrum of every two signals; Extract the phase spectrum from the cross-power spectrum of every two signals, and calculate the phase at each frequency point; Perform unwrapping processing on the phase at each frequency point to obtain a continuously changing phase; Determine the phase difference according to the continuously changing phase, and perform linear regression analysis on the frequency through the phase difference to obtain a second travel time difference data set composed of multiple travel time differences.

5. The seismic exploration method with on-site acquisition according to claim 1, characterized in that, The calculation of the path length of each seismic wave signal passing through each grid includes: Generate multiple rays starting from the position of the shearer as the seismic source and ending at the position of the geophone, and take the distance between the intersections of each ray and the grid edges of the same grid as the path length of each grid.

6. The seismic exploration method during mining according to any one of claims 1 to 5, characterized in that After the step of acquiring the seismic wave signal is implemented, the seismic exploration method during mining further includes: Preprocess the seismic wave signal.

7. A seismic exploration device for on-site acquisition, characterized in that, Including: An acquisition unit, configured to perform a seismic wave signal acquisition action once whenever the shearer runs to a target position during the process of the shearer cutting the working face, so as to acquire the seismic wave signal; A calculation unit, configured to obtain a first vibration wave data set and a second vibration wave data set from the seismic wave signal acquisition through detector groups corresponding to the transportation roadway and the return airway respectively, select the first target vibration wave data closest to the working face from the first vibration wave data set, and calculate a first travel time difference data set between each other vibration wave data in the first vibration wave data set and the first target vibration wave data; and select the second target vibration wave data closest to the working face from the second vibration wave data set, and calculate a second travel time difference data set between each other vibration wave data in the second vibration wave data set and the second target vibration wave data; An imaging unit, configured to divide the working face into grids, calculate the path length of each seismic wave signal passing through each grid, take the path length of each grid, the first travel time difference data set and the second travel time difference data set as known quantities, and use the tomography method to solve for the slowness corresponding to each grid, and perform velocity imaging according to the slowness corresponding to each grid whenever the shearer finishes cutting the working face once.

8. A computer device, comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, When the processor executes the computer program, the method according to any one of claims 1 to 6 is implemented.

9. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program, and when the computer program is executed by the processor, the method according to any one of claims 1 to 6 is implemented.

10. A computer program product, characterized in that, The computer program product includes a computer program, and when the computer program is executed by the processor, the method according to any one of claims 1 to 6 is implemented.

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