Downhole microseismic monitoring station layout method for determining small-scale gauge function

Abstract

A downhole microseismic monitoring station arrangement method for determining a small-scale gauge function, steps include determining a small-scale range gauge function calculation model, arranging displacement type microseismic monitoring stations in the form of unequal intervals in the small-scale range downhole according to the determined calculation model, determining an initiation point of an explosive blast downhole, actively exciting vibration waveforms to trigger microseismic monitoring system and seismic monitoring system to record vibration wave signals, using the magnitude published by the seismic monitoring network and the maximum displacement recorded by the microseismic monitoring station to inversely calculate the gauge function corresponding to the microseismic monitoring station in the small-scale range, and fitting the gauge function and the numerical value of the distance between the initiation point and the microseismic monitoring station to obtain the gauge function calculation formula in the small-scale range. The present application can help to reduce the blind area of signal acquisition, so that the microseismic monitoring station can completely receive the mine earthquake signal in the small-scale monitoring area, thereby improving the accuracy and reliability of the magnitude calculation.

Description

TECHNICAL FIELD

[0001] The application relates to a downhole microseismic monitoring station layout method for determining a small-scale magnitude function, and belongs to the technical field of mine earthquake magnitude calculation. BACKGROUND

[0002] In coal mine safety management, mine earthquake monitoring is an important technical means to ensure mine safety. Accurate calculation of mine earthquake magnitude is crucial for mine earthquake early warning and risk assessment.

[0003] Most of the current mine earthquake monitoring methods rely on traditional magnitude functions, which are usually based on seismic network data in a range of more than 5km, and cannot meet the needs of mine earthquake monitoring in a small-scale range. In a small-scale range of less than 5km, there is a lack of targeted coefficients, and the accuracy of the magnitude function is low. This leads to a large difference in magnitude measured by different observation points under the same instrument and station conditions, and cannot realize equivalent comparison of magnitudes in different regions. In addition, the application of existing magnitude functions in a small-scale range is limited, and the differences in geological structure in a small-scale range cannot be fully considered, resulting in insufficient accuracy of magnitude determination. In order to improve the accuracy of mine earthquake magnitude calculation, especially in a small-scale monitoring range, the reasonable layout of microseismic monitoring stations is particularly important. Therefore, how to optimize the layout of stations to ensure that the microseismic monitoring station in a small-scale monitoring range can effectively receive and record mine earthquake signals, and provide reliable data support for subsequent accurate calculation of magnitude function, has great significance. SUMMARY

[0004] The application provides a downhole microseismic monitoring station layout method for determining a small-scale magnitude function, which can help reduce the blind area of signal acquisition, so that the microseismic monitoring station can completely receive the mine earthquake signals in a small-scale monitoring area, thereby improving the accuracy and reliability of magnitude calculation.

[0005] In order to achieve the above purpose, the application provides a downhole microseismic monitoring station layout method for determining a small-scale magnitude function, comprising the following steps:

[0006] S1, determining a magnitude function calculation model in a small-scale range;

[0007] S2, arranging displacement-type microseismic monitoring stations in an unequal interval form in a small-scale range underground according to the calculation model determined in S1;

[0008] S3, determining an initiation point of an explosive blast underground, and actively exciting a vibration waveform to trigger the microseismic monitoring system and the seismic monitoring system to record the vibration wave signal;

[0009] S4, the maximum displacement recorded by the microseismic monitoring station is used to calculate the scale function corresponding to the microseismic monitoring station in a small scale range;

[0010] S5, the scale function calculation formula in a small scale range is obtained by numerical fitting of the scale function and the distance between the initiation point and the microseismic monitoring station.

[0011] Further, the small scale range in S1 is 0-5km; the scale function calculation model is: R(r) = aln(r) + b; in the formula, R(r) is the scale function, r is the distance between the initiation point and the microseismic monitoring station, a and b are combination coefficients.

[0012] Further, in S2, the displacement type microseismic monitoring stations are arranged in the form of unequal intervals, taking the center of the small scale monitoring range as the starting point, and outwardly arranging the displacement type microseismic monitoring stations in the equal ratio sequence r n = r1q n-1 , wherein r1 is in the range of 50-100m, r n is not greater than 5km, n is the total number of underground displacement type microseismic monitoring stations, and q is the proportional coefficient of the monitoring station arrangement distance, and the value formula is: wherein L is the length of the roadway in which the displacement type microseismic monitoring stations are arranged underground; the center of the small scale monitoring range is usually arranged at the starting position of the operation site of the coal mining working face underground.

[0013] Further, in S3, the initiation point position is selected as the center position of the small scale monitoring range; the vibration wave signal generated by the blasting operation reaches the clear recording of the displacement type microseismic monitoring station arranged at the farthest distance and is recorded by the national earthquake monitoring network.

[0014] Further, in S4, the magnitude M L published by the earthquake monitoring network and the maximum displacement A j measured by each displacement type microseismic monitoring station are used to calculate the scale function value R(r j ) of each microseismic monitoring station, and the calculation formula is: R(r j ) = M L -lg(A j ).

[0015] Further, in S5, the distance r j between the initiation point and the microseismic monitoring station is calculated as follows:

[0016]

[0017] In the formula, x j , y j , zj is the spatial coordinate of the jth microseismic monitoring station position; x0, y0, z0 are the spatial coordinates of the initiation point position;

[0018] The numerical fitting obtains a and b by using a linear least square method, and the formula is as follows:

[0019]

[0020] A gauge function calculation formula R(r) = aln(r) + b in a small scale range is obtained by arranging the underground microseismic monitoring station.

[0021] Further, the roadway in which the displacement type microseismic monitoring station is arranged in the coal mine underground is usually a working face crossheading near a working face of a coal mine underground mining working face.

[0022] The present application determines a gauge function calculation model in a small scale range, arranges displacement type microseismic monitoring stations in an unequal interval form in a small scale range underground according to the determined calculation model, determines an initiation point of an explosive blasting underground, initiatively excites a vibration waveform to trigger a microseismic monitoring system and a seismic monitoring system to record a vibration wave signal, inversely calculates a gauge function corresponding to the microseismic monitoring station in the small scale range by using a magnitude published by a seismic monitoring network and a maximum displacement recorded by the microseismic monitoring station, and obtains a gauge function calculation formula in the small scale range through numerical fitting of the gauge function and a distance between the initiation point and the microseismic monitoring station. The present application optimizes the arrangement scheme of the underground microseismic monitoring station, improves the precision and monitoring effect of the mine earthquake signal in the small scale range, reasonably plans the number and interval of the microseismic station, ensures that the monitoring system can comprehensively cover the small scale monitoring range and effectively capture the mine earthquake signal, provides a reliable data basis for the accurate calculation of the gauge function, and further improves the accuracy of the mine earthquake magnitude calculation. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 is a work flow chart of the present application;

[0024] Figure 2 is a schematic diagram of the arrangement of the underground microseismic monitoring station in the coal mine in the embodiment of the present application. DETAILED DESCRIPTION

[0025] The present application will be further described below in combination with the drawings.

[0026] As shown in the drawings, a method for arranging an underground microseismic monitoring station for determining a small scale gauge function comprises the following steps: Figure 1 S1, determining a gauge function calculation model in a small scale range;

[0027]

[0028] ​S2, the calculation model determined according to S1, the displacement type microseismic monitoring station is arranged in the form of unequal intervals in the small scale range of the well;

[0029] S3, the initiation point of the explosive blasting in the well is determined, the blasting operation is carried out to actively excite the vibration wave form, so as to trigger the microseismic monitoring system and the seismic monitoring system to record the vibration wave signal;

[0030] S4, the scale function corresponding to the microseismic monitoring station in the small scale range is obtained by inversely calculating the magnitude published by the seismic monitoring network and the maximum displacement recorded by the microseismic monitoring station;

[0031] S5, the scale function calculation formula of the small scale range is obtained by fitting the scale function and the numerical value of the distance between the initiation point and the microseismic monitoring station.

[0032] As a preferred embodiment, the small scale range in S1 is 0-5km; the scale function calculation model is: R(r)=aln(r)+b; in the formula, R(r) is the scale function, r is the distance between the initiation point and the microseismic monitoring station, and a and b are combination coefficients.

[0033] As shown in Figure 2 , as a preferred embodiment, the displacement type microseismic monitoring station is arranged in the form of unequal intervals, which takes the center of the small scale monitoring range as the starting point, and outwardly arranges the displacement type microseismic monitoring station in the form of equal ratio sequence r n =r1q n-1 , wherein r1 is in the range of 50-100m, r n is not greater than 5km, n is the total number of the displacement type microseismic monitoring station in the well, and q is the proportional coefficient of the monitoring station arrangement distance, and the value formula is: , wherein L is the length of the roadway in which the displacement type microseismic monitoring station is arranged in the coal mine; the center of the small scale monitoring range is usually arranged at the starting position of the operation site of the mining working face in the coal mine.

[0034] As a preferred embodiment, the position of the initiation point in S3 is selected as the center position of the small scale monitoring range; the vibration wave signal generated by the blasting operation reaches the clear record of the displacement type microseismic monitoring station arranged at the farthest distance and is recorded by the national seismic monitoring network.

[0035] As a preferred embodiment, in S4, the magnitude M L published by the seismic monitoring network and the maximum displacement A j of the vibration waveform measured by each displacement type microseismic monitoring station are used to calculate the scale function value R(r j ) of each microseismic monitoring station, and the calculation formula is: R(r j )=M L -lg(Aj )。

[0036] As a preferred embodiment, the distance r between the initiation point in S5 and the microseismic monitoring station is j The calculation formula is as follows:

[0037]

[0038] In the formula, x j , y j , z j are the spatial coordinates of the jth microseismic monitoring station; x0, y0, z0 are the spatial coordinates of the initiation point;

[0039] The values of a and b are obtained by linear least squares method, and the formula is as follows:

[0040]

[0041] The gauge function calculation formula R(r) = aln(r) + b is obtained by laying the underground microseismic monitoring station to obtain the small-scale range.

[0042] As a preferred embodiment, the roadway where the displacement type microseismic monitoring station is laid in the underground coal mine is usually the working face crossheading near the mining working face in the underground coal mine.

[0043] The present application optimizes the layout scheme of the underground microseismic monitoring station, improves the accuracy and monitoring effect of the mine earthquake signal in a small-scale range, reasonably plans the number and spacing of the microseismic station, ensures that the monitoring system can fully cover the small-scale monitoring range, effectively captures the mine earthquake signal, provides a reliable data basis for the accurate calculation of the gauge function, and further improves the accuracy of the mine earthquake magnitude calculation.

Claims

1. A method for determining a downhole microseismic monitoring station layout for a small-scale metric function, characterized by, It comprises the following steps: S1, determining a gauge function calculation model in a small scale range; S2, arranging displacement type microseismic monitoring stations in an unequal interval form in the small scale range according to the calculation model determined in S1; S3, determining an initiation point of an explosive blasting in the well, and carrying out a blasting operation to actively excite a vibration waveform to trigger a microseismic monitoring system and a seismic monitoring system to record a vibration wave signal; S4, using a magnitude published by a seismic monitoring network and a maximum displacement recorded by the microseismic monitoring station to inversely calculate a gauge function corresponding to the microseismic monitoring station in the small scale range; S5, fitting the gauge function and a distance between the initiation point and the microseismic monitoring station to obtain a gauge function calculation formula in the small scale range; The small scale range in S1 is 0-5km; the gauge function calculation model is R(r)=aln(r)+b; in the formula, R(r) is a gauge function, r is a distance between the initiation point and the microseismic monitoring station, and a and b are combination coefficients; The displacement type microseismic monitoring station in the unequal spacing form in S2 is set outward from the center of a small scale monitoring range as a starting point with an equi-proportion series r n = r1q n-1 The displacement type microseismic monitoring station is set underground, wherein r1 is in the range of 50-100 m, r n is not greater than 5 km, n is the total number of the displacement type microseismic monitoring station underground, and q is a proportional coefficient of the monitoring station setting distance, and the value formula is: Wherein, L is the roadway length of the displacement type microseismic monitoring station set underground in the coal mine; the center of the small scale monitoring range is set at the starting position of the operation site of the mining working face underground in the coal mine; The magnitude M in S4 is released using the earthquake monitoring network. L And the maximum displacement A of the vibration waveform measured by each displacement-type microseismic monitoring station. j The gauge function values ​​R(r) of each microseismic monitoring station were calculated. j The calculation formula is: R(r) j ) = M L -lg(A j ); The distance r between the initiation point in S5 and the microseismic monitoring station j The calculation formula is as follows: In the formula, x j , y j , z j are the spatial coordinates of the jth microseismic monitoring station position; x0, y0, z0 are the spatial coordinates of the shot point position; a and b are obtained by using a linear least square method for numerical fitting, and the formula is as follows: The gauge function calculation formula R(r)=aln(r)+b in the small scale range is obtained by arranging the microseismic monitoring station in the well.

2. The downhole microseismic monitoring station layout method for determining small-scale metric functions of claim 1, wherein, The initiation point position in S3 is selected as a center position of the small scale monitoring range; the vibration wave signal generated by the blasting operation reaches a displacement type microseismic monitoring station arranged at the farthest distance and is clearly recorded, and is recorded by the national seismic monitoring network at the same time.

3. The downhole microseismic monitoring station layout method for determining small-scale metric functions of claim 1, wherein, The roadway in which the displacement type microseismic monitoring station is arranged in the coal mine well is a working face crossheading near a coal mine well mining working face.

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