A micro-motion exploration method based on koch fractal curve

Abstract

A micro-motion exploration method based on Koch fractal curve, first determine the target area, then set the order N to zero, then determine the zero-order Koch triangle, then determine the first-order to N-order Koch triangle in turn, until the order N is the final value, then bring the order N into the Koch fractal curve to generate the N-order Koch triangle graph, the N-order Koch triangle graph includes a plurality of sharp points and a center point, all sharp points and the center point are the layout points of the seismograph; then lay out the seismograph on the layout points, then monitor by the seismograph to obtain the micro-motion signal, then obtain the shear wave velocity three-dimensional structure, after laying out, a plurality of Koch triangles with different edge lengths are obtained, so the micro-motion signals with different station spacings are obtained, then the shear wave velocity three-dimensional structures of multiple depths can be obtained; without multiple laying, the exploration efficiency is higher. Therefore, the design can obtain the shear wave velocity three-dimensional structures of multiple depths at the same time, and the exploration efficiency is higher.

Description

TECHNICAL FIELD

[0001] The present application relates to a microseismic exploration method, belonging to the field of microseismic exploration, in particular to a microseismic exploration method based on Koch fractal curve. BACKGROUND

[0002] Microseismic refers to the daily slight tremor of the earth's surface, and the microseismic signal is obtained after the microseismic of the target area is explored, and the three-dimensional structure of shear wave velocity under the target area can be obtained by processing the microseismic signal through spatial autocorrelation method, so as to obtain the underground structure of the target area.

[0003] The patent with the application number 202210249722.5 and the application date of March 14, 2022 discloses a three-dimensional microseismic detection array layout and detection analysis method, which first lays out a three-dimensional microseismic detection array with a square array structure, in which a measuring point is arranged at the coordinate position of each node seismograph, and each measuring point adopts an L-shaped array for microseismic detection, then each measuring point selects corresponding measuring points to form an L-shaped array according to a measuring point observation system combination formula, and the collected data of each measuring point L-shaped array is extracted for frequency dispersion and inversion, a three-dimensional phase velocity map is made and displayed, although this design can obtain the three-dimensional structure of shear wave velocity under the target area, but still has the following defects:

[0004] In the design, the spacing between each measuring point is the same, and after processing by spatial autocorrelation method, only the three-dimensional structure of shear wave velocity at the same depth can be obtained, when the three-dimensional structure of shear wave velocity at different depths is needed, the spacing between measuring points needs to be adjusted again, and monitoring is performed again to obtain the three-dimensional structure of shear wave velocity at another depth, so the exploration efficiency is low.

[0005] The information disclosed in this background section is only intended to increase the understanding of the general background of the application, and should not be considered as recognition or in any form as admitting that this information constitutes prior art known to those of ordinary skill in the art. SUMMARY

[0006] The purpose of the present application is to overcome the defects and problems of the prior art that cannot obtain the three-dimensional structure of shear wave velocity at multiple depths at the same time and the low exploration efficiency, and to provide a microseismic exploration method based on Koch fractal curve which can obtain the three-dimensional structure of shear wave velocity at multiple depths at the same time and has high exploration efficiency.

[0007] To achieve the above purpose, the technical solution of the present application is:

[0008] A microseismic exploration method based on Koch fractal curve, the method comprising the following steps:

[0009] The first step is to determine the target area, then determine the maximum underground depth and the minimum underground depth that need to be detected in the target area, then multiply the maximum underground depth by the conversion coefficient to obtain the maximum side length, and then multiply the minimum underground depth by the conversion coefficient to obtain the minimum side length.

[0010] The second step is to set the order N to zero first, then determine the maximum side length as the side length of the zero-order Koch triangle, that is, obtain the zero-order Koch triangle; then take the zero-order Koch triangle as the basis, and then start the determination process: first increase the order N by one, then determine the side length of the N-order Koch triangle and the proportional coefficient of the (N-1)-order Koch triangle, which is less than one, then multiply the proportional coefficient by the side length of the (N-1)-order Koch triangle to obtain the side length of the N-order Koch triangle, that is, obtain the N-order Koch triangle.

[0011] The third step is to take the N-order Koch triangle as the basis, and then repeat the determination process in the third step until the length of the side length of the N-order Koch triangle is less than or equal to the minimum side length, at this time, the order N is the final value.

[0012] The fourth step is to first input the order N into the Koch fractal curve to generate an N-order Koch triangle graph, the outer edge of the N-order Koch triangle graph is distributed with a plurality of sharp points, and a center point exists in the middle of the N-order Koch triangle graph, all sharp points and the center point are the layout points of the seismograph.

[0013] The fifth step is to first sequentially arrange the seismograph at all the sharp points, and then arrange the seismograph at the center point.

[0014] The sixth step is to first monitor all the seismographs simultaneously, then obtain a plurality of micro-motion signals, and then obtain the shear wave velocity three-dimensional structure below the target area according to the micro-motion signals.

[0015] In the second step, the proportional coefficient is one-third.

[0016] In the fourth step, the outer edge of the N-order Koch triangle graph includes a plurality of straight line segments, and the points between adjacent two straight line segments are sharp points.

[0017] In the fourth step, the included angle between adjacent two straight line segments is sixty degrees or one hundred and twenty degrees.

[0018] In the fourth step, the final value is two, at this time, the length of the side length of the N-order Koch triangle is less than or equal to the minimum side length.

[0019] In the first step, the conversion coefficient is between one-fourth and one-tenth.

[0020] In the sixth step, the step of analyzing the micro-motion signal to generate the dispersion curve comprises the steps of: calculating the micro-motion signal to obtain a spatial autocorrelation coefficient by using a spatial autocorrelation method; and fitting the spatial autocorrelation coefficient with a Bessel function, and then generating the dispersion curve.

[0021] In the sixth step, the step of analyzing the micro-motion signal to generate the dispersion curve comprises the steps of: calculating the micro-motion signal to obtain a spatial autocorrelation coefficient by using a spatial autocorrelation method; and fitting the spatial autocorrelation coefficient with a Bessel function, and then generating the dispersion curve.

[0022] In the sixth step, the step of inverting the dispersion curve to obtain the three-dimensional structure of the shear wave velocity under the target area comprises the steps of: inverting the dispersion curve by using a half-wave length empirical formula to obtain a relationship between the depth and the surface wave phase velocity; and obtaining the three-dimensional structure of the shear wave velocity under the target area from the relationship between the depth and the surface wave phase velocity.

[0023] In the sixth step, the step of analyzing the micro-motion signal comprises the steps of: removing invalid signals in the micro-motion signal; obtaining valid micro-motion signals; and analyzing the valid micro-motion signals.

[0024] Compared with the prior art, the micro-motion exploration method based on the Koch fractal curve has the following beneficial effects:

[0025] 1. In the micro-motion exploration method based on the Koch fractal curve, the method comprises the following steps: first, determining a target area, a maximum underground depth and a minimum underground depth to be detected, and then converting the maximum underground depth and the minimum underground depth to obtain a maximum edge length and a minimum edge length; second, setting the order N to zero, and then determining the edge length of a zero-order Koch triangle, and then determining the edge length of an N-order Koch triangle; third, repeating the second step until the edge length of the N-order Koch triangle is less than or equal to the minimum edge length, at this time, N is the final value; fourth, inputting the order N into the Koch fractal curve to generate an N-order Koch triangle graph, and then obtaining a sharp point and a center point from the N-order Koch triangle graph, and the sharp point and the center point are the layout points of the seismographs; fifth, laying the seismographs on the sharp point and the center point; and sixth, simultaneously monitoring all the seismographs to obtain micro-motion signals, and then obtaining a three-dimensional structure of a shear wave velocity according to the micro-motion signals.

[0026] Firstly, the edge lengths of the zero-order Koch triangle, the first-order Koch triangle, the second-order Koch triangle and the N-order Koch triangle are shortened in turn, so that the inter-station distances between the seismographs laid on the respective vertices are shortened in turn, and therefore the micro-motion signals of different inter-station distances can be obtained, and the three-dimensional structures of the shear wave velocities at different depths can be obtained by processing the micro-motion signals of different inter-station distances by using the spatial autocorrelation method.

[0027] Secondly, after once laying out, the seismograph monitoring can obtain the microseismic signals of different station spacings simultaneously without laying out the seismographs of different station spacings for many times, thereby saving the laying-out time and labor cost, and improving the exploration efficiency;

[0028] Thirdly, a large number of equilateral triangles with different side lengths are perfectly nested in the Koch curve, which matches the triangle station array required by the spatial autocorrelation method, so that the Koch curve is very suitable for laying out the triangle station array.

[0029] Fourthly, the side length of the (N-1) order Koch triangle is taken as one-third of the center length, and the one-third length is taken as the side length of the N order Koch triangle, so that the self-similarity of the fractal can be ensured, the N order Koch triangle with shorter side length can be generated according to the method in each iteration, and the N order Koch triangles do not interfere with each other, so that the iteration process is stable.

[0030] Therefore, the present application can obtain the shear wave velocity three-dimensional structure of multiple depths simultaneously, and the exploration efficiency is high.

[0031] 2. In the microseismic exploration method based on the Koch fractal curve, the N order Koch triangle graph in the fourth step includes a plurality of straight line segments, and the included angle between adjacent two straight line segments is sixty degrees or one hundred and twenty degrees, so that the N order Koch triangle is an equilateral triangle, and the requirement of the triangle station array commonly used in the spatial autocorrelation method is met.

[0032] 3. In the microseismic exploration method based on the Koch fractal curve, the final value is two in the fourth step, and the conversion coefficient is between one-fourth and one-tenth in the first step, so that when the final value of N is two, the second order Koch triangle graph can be generated by bringing two into the Koch fractal curve, and then the apex and the center point of the second order Koch triangle graph are obtained.

[0033] 4. In the microseismic exploration method based on the Koch fractal curve, in the fifth step, the microseismic signals are processed by the spatial autocorrelation method to obtain the spatial autocorrelation coefficient, the spatial autocorrelation coefficient is fitted with the Bessel function, then the dispersion curve is obtained, the dispersion curve is inverted by the half-wave empirical formula to obtain the three-dimensional structure of the shear wave velocity under the target area, and then the underground structure of the target area is judged by the three-dimensional structure of the shear wave velocity, when applied, the spatial autocorrelation method can consider the spatial dependence and autocorrelation between the microseismic signals, so that the three-dimensional structure of the shear wave velocity can be obtained accurately, and the spatial autocorrelation method can efficiently process a large amount of microseismic signals, so that the data processing efficiency is higher. Therefore, the accuracy of the present application is higher. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 is a structural schematic diagram of the present application.

[0035] Figure 2 is Figure 1 is a structural schematic diagram of the zero-order Koch triangle in the present application.

[0036] Figure 3 is Figure 1 is a structural schematic diagram of the (N-1) order Koch triangle in the present application.

[0037] Figure 4 is Figure 1 is a structural schematic diagram of the N order Koch triangle in the present application.

[0038] Figure 5 is Figure 4 is a structural schematic diagram of the sharp point in the present application.

[0039] Figure 6 is a schematic diagram of the three-dimensional structure of the shear wave velocity in the present application.

[0040] Figure 7 is a schematic diagram of the judgment result in Example 4.

[0041] Figure 8 is a structural schematic diagram of Example 5.

[0042] Figure 9 is Figure 8 is a structural schematic diagram of the lower half plate in the present application.

[0043] Figure 10 is Figure 8 is a structural schematic diagram of the upper half plate in the present application.

[0044] Figure 11 is Figure 8 is a structural schematic diagram of the fourth triangle in the present application.

[0045] In the figure: target area 1, zero-order Koch triangle 2, N-order Koch triangle 3, N-order Koch triangle diagram 31, sharp point 32, center point 33, straight line segment 34, (N-1)-order Koch triangle 4, device 5, upper half plate 51, first triangle 511, second triangle 512, third triangle 513, upper half center point 514, lower half plate 52, fourth triangle 521, fifth triangle 522, sixth triangle 523, lower half center point 524, shear wave velocity three-dimensional structure 6, first layout point 71, second layout point 72, third layout point 73, fourth layout point 74, fifth layout point 75, sixth layout point 76, seventh layout point 77, eighth layout point 78, ninth layout point 79, tenth layout point 80, eleventh layout point 81, twelfth layout point 82. DETAILED DESCRIPTION

[0046] The application will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0047] Please refer to Figure 1 Figure 11 A micro-motion exploration method based on Koch fractal curve, the method comprising the following steps:

[0048] First step: first determine the target area 1, then determine the maximum underground depth and the minimum underground depth that need to be detected in the target area 1, then multiply the maximum underground depth by the conversion coefficient to obtain the maximum edge length, and then multiply the minimum underground depth by the conversion coefficient to obtain the minimum edge length;

[0049] Second step: first set the order N to zero, then determine the edge length of the zero-order Koch triangle 2 as the edge length of the zero-order Koch triangle 2, that is, obtain the zero-order Koch triangle 2; then, based on the zero-order Koch triangle 2, start the determination process: first increase the order N by one, then determine the edge length of the N-order Koch triangle 3 and the proportion coefficient of the (N-1)-order Koch triangle 4, which is less than one, then multiply the proportion coefficient by the edge length of the (N-1)-order Koch triangle 4 to obtain the edge length of the N-order Koch triangle 3, that is, obtain the N-order Koch triangle 3;

[0050] Third step: first, based on the N-order Koch triangle 3, then repeat the determination process in the third step until the length of the edge length of the N-order Koch triangle 3 is less than or equal to the minimum edge length, at this time, the order N is the final value;

[0051] Fourth step: first, bring the order N into the Koch fractal curve to generate the N-order Koch triangle diagram 31, the N-order Koch triangle diagram 31 has a plurality of sharp points 32 distributed on the outer edge, and there is a center point 33 in the middle of the N-order Koch triangle diagram 31, all the sharp points 32 and the center point 33 are the layout points of the seismograph;

[0052] ​Fifth step: first, sequentially arrange seismographs on all the cusps 32, and then arrange a seismograph on the center point 33;

[0053] Sixth step: first, simultaneously monitor all the seismographs, then obtain multiple micro-motion signals, and then obtain the three-dimensional shear wave velocity structure 6 under the target area 1 according to the micro-motion signals.

[0054] In the second step, the proportion coefficient is one third.

[0055] In the fourth step, the outer edge of the N-order Koch triangle graph 31 comprises multiple straight line segments 34, and the point between two adjacent straight line segments 34 is a cusp 32.

[0056] In the fourth step, the included angle between two adjacent straight line segments 34 is sixty degrees or one hundred and twenty degrees.

[0057] In the fourth step, the final value is two, and at this time, the length of the edge length of the N-order Koch triangle 3 is less than or equal to the minimum edge length.

[0058] In the first step, the conversion coefficient is between one fourth and one tenth.

[0059] In the sixth step, the three-dimensional shear wave velocity structure 6 under the target area 1 according to the micro-motion signals is that the micro-motion signals are analyzed to generate a dispersion curve, and then the dispersion curve is inverted to obtain the three-dimensional shear wave velocity structure 6 under the target area 1.

[0060] In the sixth step, the analysis of the micro-motion signals to generate the dispersion curve is that the spatial autocorrelation method is used to calculate the micro-motion signals to obtain a spatial autocorrelation coefficient, then the spatial autocorrelation coefficient is fitted with a Bessel function, and then the dispersion curve is generated.

[0061] In the sixth step, the inversion of the dispersion curve to obtain the three-dimensional shear wave velocity structure 6 under the target area 1 is that the dispersion curve is inverted by a half-wave empirical formula to obtain the relationship between depth and surface wave phase velocity, and then the three-dimensional shear wave velocity structure 6 under the target area 1 is obtained from the relationship between depth and surface wave phase velocity.

[0062] In the sixth step, the analysis of the micro-motion signals is that the invalid signals in the micro-motion signals are removed, then the effective micro-motion signals are obtained, and then the effective micro-motion signals are analyzed.

[0063] The supplementary explanation of the application is as follows:

[0064] The Koch fractal curve is generated by a recursive definition, and the specific construction process is that a line segment is divided into three equal parts, a right triangle is formed with the middle segment as a side, and the original line segment is removed to form a first-order Koch triangle; each line segment of the first-order Koch triangle is repeated the above steps to obtain a second-order Koch triangle; in this way, higher-order Koch triangles can be obtained; in the process of constructing the Koch triangle, different triangles with different side lengths are added in each iteration, so the space autocorrelation method can be combined with this point, that is, a seismic station array with different inter-station distances is obtained, so that the three-dimensional structure of the shear wave velocity at different depths can be obtained.

[0065] Embodiment 1

[0066] See Figure 1 — Figure 11 A microseismic exploration method based on a Koch fractal curve, the method comprising the following steps:

[0067] First step: first determine the target area 1, then determine the maximum underground depth and the minimum underground depth that need to be detected in the target area 1, then multiply the maximum underground depth by the conversion coefficient to obtain the maximum side length, and then multiply the minimum underground depth by the conversion coefficient to obtain the minimum side length;

[0068] Second step: first set the order N to zero, then determine the edge length of the zero-order Koch triangle 2 as the edge length of the zero-order Koch triangle 2, that is, obtain the zero-order Koch triangle 2; then, based on the zero-order Koch triangle 2, start the determination process: first increase the order N by one, then determine the edge length of the N-order Koch triangle 3 and the proportional coefficient of the (N-1)-order Koch triangle 4, the proportional coefficient is less than one, then multiply the proportional coefficient by the edge length of the (N-1)-order Koch triangle 4 to obtain the edge length of the N-order Koch triangle 3, that is, obtain the N-order Koch triangle 3;

[0069] Third step: first take the N-order Koch triangle 3 as the basis, then repeat the determination process in the third step until the length of the edge length of the N-order Koch triangle 3 is less than or equal to the minimum edge length, at this time, the order N is the final value;

[0070] Fourth step: first input the order N into the Koch fractal curve to generate the N-order Koch triangle graph 31, the N-order Koch triangle graph 31 has a plurality of sharp points 32 distributed on the outer edge, and the N-order Koch triangle graph 31 has a center point 33 in the middle part, all the sharp points 32 and the center point 33 are the layout points of the seismographs;

[0071] Fifth step: first sequentially arrange the seismographs on all the sharp points 32, and then arrange the seismographs on the center point 33;

[0072] Sixth step: first, all the seismographs are monitored simultaneously, then multiple micro-motion signals are obtained, and then the shear wave velocity three-dimensional structure 6 under the target area 1 is obtained according to the micro-motion signals.

[0073] In the second step, the proportion coefficient is one third.

[0074] Embodiment 2:

[0075] The basic content is the same as that of embodiment 1, except that:

[0076] Please refer to Figure 1 — Figure 5 In the fourth step, the outer edge of the N-order Koch triangle diagram 31 includes multiple straight line segments 34, and the point between adjacent two straight line segments 34 is a sharp point 32. In the fourth step, the included angle between adjacent two straight line segments 34 is sixty degrees or one hundred and twenty degrees.

[0077] In application, the point between adjacent two straight line segments 34 is a sharp point 32, which is the vertex of the N-order Koch triangle 3, that is, the layout point of the seismograph; the included angle between adjacent two straight line segments 34 is sixty degrees or one hundred and twenty degrees, which ensures that the N-order Koch triangle 3 is a regular triangle, so the N-order Koch triangle 3 can perfectly fit the spatial autocorrelation method.

[0078] Embodiment 3:

[0079] The basic content is the same as that of embodiment 1, except that:

[0080] Please refer to Figure 1 — Figure 5 In the fourth step, the final value is two, at this time, the length of the edge length of the N-order Koch triangle 3 is less than or equal to the minimum edge length. In the first step, the conversion coefficient is between one fourth and one tenth.

[0081] In application, when the final value is two, first substitute two into the Koch fractal curve, then generate a two-order Koch triangle diagram as shown in Figure 4 , then get the sharp point 32 and the center point 33 according to the two-order Koch triangle diagram, and then layout the seismographs in the sharp point 32 and the center point 33. The two-order Koch triangle can meet the basic exploration demand, and the inter-station distance of the seismographs on the sharp point 32 and the center point 33 is appropriate, which can explore the shear wave velocity three-dimensional structure 6 of the required depth; the number of repetitions of the determination process in the second step can also be set according to needs. When the number of repetitions is large, the distribution of the seismographs near the center point 33 will be less. When there is an exploration demand for a shallow depth at the center point 33, the station array of the seismograph at the center point 33 needs to be increased according to the actual situation; the conversion coefficient is determined by the characteristics of the spatial autocorrelation method, and the maximum edge length and the minimum edge length can be determined according to the detection requirement combined with the conversion coefficient.

[0082] Example 4:

[0083] The basic content is the same as that of Example 1, except that:

[0084] Please refer to Figure 1 — Figure 7 In the sixth step, the three-dimensional structure 6 of the shear wave velocity under the target area 1 is obtained by analyzing the microseismic signal to generate a dispersion curve, and then inverting the dispersion curve to obtain the three-dimensional structure 6 of the shear wave velocity under the target area 1. In the sixth step, the microseismic signal is analyzed to generate a dispersion curve by first calculating the spatial autocorrelation coefficient of the microseismic signal to obtain the spatial autocorrelation coefficient, then fitting the spatial autocorrelation coefficient with the Bessel function, and then generating the dispersion curve. In the sixth step, the dispersion curve is inverted to obtain the three-dimensional structure 6 of the shear wave velocity under the target area 1 by inverting the dispersion curve by the half-wavelength empirical formula to obtain the relationship between depth and surface wave phase velocity, and then obtaining the three-dimensional structure 6 of the shear wave velocity under the target area 1 from the relationship between depth and surface wave phase velocity. In the sixth step, the microseismic signal is analyzed by first removing the invalid signal in the microseismic signal, then obtaining the effective microseismic signal, and then analyzing the effective microseismic signal.

[0085] In application, in the fifth step, the microseismic signal obtained is preprocessed to remove invalid signals in the microseismic signal, then effective microseismic signals are obtained, then the effective microseismic signals are calculated by the spatial autocorrelation method, then the spatial autocorrelation coefficient is obtained, then the spatial autocorrelation coefficient is fitted with the Bessel function, then the dispersion curve is obtained, then the surface wave phase velocity and frequency are obtained from the dispersion curve, then the surface wave phase velocity and frequency are brought into the half-wavelength empirical formula to calculate the relationship between depth and surface wave phase velocity, then the surface wave phase velocity is converted into shear wave velocity, then the relationship between depth and shear wave velocity is obtained, that is, a set of microseismic signal processing results of Kech triangles is obtained; repeat the processing process until the processing results of the remaining sets of Kech triangles of microseismic signals are obtained, then all the processing results are processed by the interpolation method, then the three-dimensional structure 6 of the shear wave velocity under the target area 1 is obtained as shown in Figure 6 , then the underground structure of the target area 1 is judged by the three-dimensional structure 6 of the shear wave velocity under the target area 1, and the judgment result can be referred to Figure 7 .

[0086] Example 5:

[0087] The basic content is the same as that of Example 1, except that:

[0088] Please refer to Figure 1 — Figure 11A layout device for a micro-prospecting method based on Koch fractal curve, the device 5 comprises an upper half plate 51 and a lower half plate 52, the upper half plate 51 comprises a first triangle 511, the first triangle 511 is a right triangle, a second triangle 512 is arranged on one side of the bottom of the first triangle 511, the second triangle 512 is a right triangle, a third triangle 513 is arranged on the other side of the bottom of the first triangle 511, the third triangle 513 is a right triangle, and a middle of the bottom of the first triangle 511 is provided with an upper half midpoint 514; the lower half plate 52 comprises a fourth triangle 521, the fourth triangle 521 is a right triangle, a fifth triangle 522 is arranged on one side of the bottom of the fourth triangle 521, the fifth triangle 522 is a right triangle, a sixth triangle 523 is arranged on the other side of the bottom of the fourth triangle 521, the sixth triangle 523 is a right triangle, and a middle of the bottom of the fourth triangle 521 is provided with a lower half midpoint 524. Preferably, the vertices on the mold 5 are in turn a first layout point 71, a second layout point 72, a third layout point 73, a fourth layout point 74, a fifth layout point 75, a sixth layout point 76, a seventh layout point 77, an eighth layout point 78, a ninth layout point 79, a tenth layout point 80, an eleventh layout point 81, and a twelfth layout point 82.

[0089] In application, first, the target area 1 is determined, then the upper half plate 51 and the lower half plate 52 are placed in the target area 1, then the upper half midpoint 514 and the lower half midpoint 524 are aligned, then the seismographs are arranged between the first layout point 71, the second layout point 72, the third layout point 73, the fourth layout point 74, the fifth layout point 75, the sixth layout point 76, the seventh layout point 77, the eighth layout point 78, the ninth layout point 79, the tenth layout point 80, the eleventh layout point 81, the twelfth layout point 82, the thirteenth layout point 83, the fourteenth layout point 84, the upper half midpoint 514 and the lower half midpoint 524, then the seismographs are monitored, the first layout point 71, the twelfth layout point 82 and the tenth layout point 80 form a zero-order Koch triangle 2, the station interval of the seismographs on the first layout point 71, the twelfth layout point 82 and the tenth layout point 80 is large, so it is used for exploring the shear wave velocity three-dimensional structure 6 of a deeper depth; the station interval of the seismographs on the fifth layout point 75, the sixth layout point 76 and the seventh layout point 77 is small, so it can be used for exploring the shear wave velocity three-dimensional structure 6 of a shallower depth; the station interval of the seismographs on the second layout point 72, the third layout point 73 and the fourth layout point 74 is small, so it can be used for exploring the shear wave velocity three-dimensional structure 6 of a shallower depth; the station interval of the seismographs on the ninth layout point 79, the tenth layout point 80 and the fourth layout point 74 is small, so it can be used for exploring the shear wave velocity three-dimensional structure 6 of a shallower depth; the station interval of the seismographs on the eleventh layout point 81, the twelfth layout point 82 and the fifth layout point 75 is small, so it can be used for exploring the shear wave velocity three-dimensional structure 6 of a shallower depth; when the mold 5 is used, the station interval between the seismographs does not need to be measured and determined, the seismographs can be directly arranged between the first layout point 71, the second layout point 72, the third layout point 73, the fourth layout point 74, the fifth layout point 75, the sixth layout point 76, the seventh layout point 77, the eighth layout point 78, the ninth layout point 79, the tenth layout point 80, the eleventh layout point 81, the twelfth layout point 82, the thirteenth layout point 83, the fourteenth layout point 84, the upper half midpoint 514 and the lower half midpoint 524, so the arrangement time is saved and the arrangement efficiency is improved.

[0090] The above merely describes the preferred embodiments of the present application, and the protection scope of the present application is not limited to the above embodiments, but any equivalent modification or change made by those skilled in the art according to the disclosed content of the present application shall be included in the protection scope recorded in the claims.

Claims

1. A microseismic exploration method based on a Koch fractal curve, characterized in that: The method comprises the following steps: The first step is to determine the target area (1), then determine the maximum underground depth and the minimum underground depth that need to be detected in the target area (1), then multiply the maximum underground depth by the conversion coefficient to obtain the maximum side length, and then multiply the minimum underground depth by the conversion coefficient to obtain the minimum side length; The second step is to set the order N to zero, then determine the maximum side length as the side length of the zero-order Koch triangle (2), that is, to obtain the zero-order Koch triangle (2); then take the zero-order Koch triangle (2) as the basis, and then start the determination process: first increase the order N by one, then determine the side length of the N-order Koch triangle (3) and the proportional coefficient of the (N-1)-order Koch triangle (4), which is less than one, then multiply the proportional coefficient by the side length of the (N-1)-order Koch triangle (4) to obtain the side length of the N-order Koch triangle (3), that is, to obtain the N-order Koch triangle (3); The third step is to take the N-order Koch triangle (3) as the basis, and then repeat the determination process in the second step until the length of the side length of the N-order Koch triangle (3) is less than or equal to the minimum side length, at this time, the order N is the final value; The fourth step is to bring the order N into the Koch fractal curve to generate an N-order Koch triangle graph (31), a plurality of sharp points (32) are distributed on the outer edge of the N-order Koch triangle graph (31), and a center point (33) exists in the middle of the N-order Koch triangle graph (31), all sharp points (32) and the center point (33) are the layout points of the seismograph; The fifth step is to sequentially arrange the seismograph on all the sharp points (32) and arrange the seismograph on the center point (33); The sixth step is to simultaneously monitor all the seismographs, obtain a plurality of micro-motion signals, and then obtain the shear wave velocity three-dimensional structure (6) below the target area (1) according to the micro-motion signals.

2. A microseismic survey method based on Koch fractal curve according to claim 1, characterized in that: In the second step, the proportional coefficient is one-third.

3. A microseismic survey method based on Koch fractal curve according to claim 1 or 2, characterized in that: In the fourth step, the outer edge of the N-order Koch triangle graph (31) comprises a plurality of straight line segments (34), and the points between adjacent two straight line segments (34) are sharp points (32).

4. A microseismic survey method based on Koch fractal curve according to claim 3, characterized in that: In the fourth step, the included angle between adjacent two straight line segments (34) is sixty degrees or one hundred and twenty degrees.

5. The microseismic exploration method based on Koch fractal curve according to claim 1 or 2, characterized in that: In the third step, the final value is two, at this time, the length of the side length of the N-order Koch triangle (3) is less than or equal to the minimum side length.

6. A microseismic survey method based on Koch fractal curve according to claim 5, characterized in that: In the first step, the conversion coefficient is between one-fourth and one-tenth.

7. The method of claim 1, wherein the method is based on a Koch fractal curve. In the sixth step, the shear wave velocity three-dimensional structure (6) below the target area (1) obtained according to the micro-motion signals is that the micro-motion signals are analyzed to generate a dispersion curve, and then the dispersion curve is inverted to obtain the shear wave velocity three-dimensional structure (6) below the target area (1).

8. A microseismic survey method based on Koch fractal curve according to claim 7, characterized in that: In the sixth step, the analysis of the micro-motion signals to generate the dispersion curve is that the spatial autocorrelation method is adopted to calculate the micro-motion signals to obtain a spatial autocorrelation coefficient, then the spatial autocorrelation coefficient is fitted with a Bessel function, and then the dispersion curve is generated.

9. A microseismic survey method based on Koch fractal curve according to claim 8, characterized in that: In the sixth step, the dispersion curve is inverted to obtain the three-dimensional structure (6) of shear wave velocity under the target area (1) by inverting the dispersion curve by a half wavelength empirical formula to obtain the relationship between depth and surface wave phase velocity, and then obtaining the three-dimensional structure (6) of shear wave velocity under the target area (1) from the relationship between depth and surface wave phase velocity.

10. A microseismic survey method based on Koch fractal curve according to claim 9, characterized in that: In the sixth step, the micro-motion signal is analyzed by removing the invalid signal in the micro-motion signal first, obtaining the effective micro-motion signal, and then analyzing the effective micro-motion signal.

Images