阅读说明：本技术 一种煤层底板隐伏构造探测方法 (Method for detecting hidden structure of coal seam floor ) 是由 李德春 匡伟 梁红波 于 2020-04-28 设计创作，主要内容包括：本发明公开了一种煤层底板隐伏构造探测方法,在基础理论方面,将低频的槽波和P、S波综合在一起,充分利用了所有包含底板构造的信息；在施工方法方面,将炮点布设在位于接近底板约1m处,将检波器布设在巷道底和煤壁分界处,采用Y分量接收。该参数通过大量试验得到；数据处理方面,设计了基于概率统计方法的滑行波能量矫正方法,使得矫正后滑行波能量分布在0～1之间,而不损坏其中包含的构造信息,从而实现滑行波能量成析成像；本发明从基础理论方面展开研究,设计了滑行波探测施工方法,研究了一整套针对滑行波能量层析成像的数据处理方法从而可以实现煤层底板隐伏构造的探测,对于煤矿底板水害防治具有极其重要的意义。(The invention discloses a method for detecting a hidden structure of a coal seam floor, which integrates low-frequency channel waves and P, S waves in the aspect of basic theory and fully utilizes all information containing the floor structure; in the construction method, the shot points are arranged at the position which is about 1m close to the bottom plate, the detectors are arranged at the boundary of the roadway bottom and the coal wall, and the Y component is adopted for receiving. This parameter is obtained by a number of tests; in the aspect of data processing, a probability statistics method-based taxiwave energy correction method is designed, so that corrected taxiwave energy is distributed between 0 and 1 without damaging structural information contained in the corrected taxiwave energy, and thereby, taxiwave energy analytic imaging is realized; the invention develops research from the aspect of basic theory, designs a gliding wave detection construction method, and researches a whole set of data processing method aiming at gliding wave energy tomography so as to realize the detection of the hidden structure of the coal seam floor, thereby having extremely important significance for preventing and controlling the water damage of the coal seam floor.)

1. A method for detecting a hidden structure of a coal seam floor is characterized in that a stope working face is used as a construction site, the working face is required to finish at least two tunneling roadways, and the method has a condition of transmitting to the working face, and the specific construction method comprises the following steps:

1) arranging shot points along one roadway and arranging wave detection points along the other roadway;

2) the arrangement position of the shot points is 1m +/-0.1 m close to the interface of the bottom plate;

3) the wave detection point is arranged at the boundary of the roadway bottom and the coal wall and is received by using a y component;

4) sequentially exciting one by one during blasting, receiving by adopting a fully-arranged geophone, and recording data by a gliding wave seismometer;

the data processing method comprises the following steps:

5) data preprocessing

The data preprocessing comprises conventional preprocessing and special preprocessing, the conventional preprocessing is similar to the ground three-dimensional seismic exploration data preprocessing, and the special preprocessing is mainly used for processing the gliding waves;

6) extraction of gliding wave energy

Extracting parameter data of low-frequency channel waves, P waves of normal frequency bands and S waves of normal frequency bands, and manually picking up parameters of the three types of waves by adopting a time window opening method, wherein the energy is a real amplitude energy value obtained by recording, enveloping, calculating, summing and performing stratum attenuation compensation in a time window;

7) correction of gliding wave energy

An energy correction algorithm is adopted to correct the gliding wave energy difference caused by factors such as offset, excitation dose and detector coupling, and the corrected energy parameters can be directly used for tomography;

8) tomography of gliding wave energy

The tomography adopts direct ray forward algorithm and SIRT inversion algorithm, and the gliding wave energy tomography algorithm is as follows:

a) establishing a working face initial model and dividing a computational grid;

b) tracking the straight rays, namely multiplying energy by corresponding offset distance, and then distributing the energy to each grid according to the length of the rays;

c) performing inversion solution according to the difference value between the theoretical energy and the actually picked energy, and correcting the model;

d) carrying out interpolation processing on the corrected model;

e) smoothing the corrected model;

f) and repeating the four steps b to e until the model modification meets certain requirements.

2. The method for detecting the hidden structure of the coal seam floor as claimed in claim 1, wherein the distance between the shot points in 2) is 5-10 m.

3. The method for detecting the hidden structure of the coal seam floor as claimed in claim 1, wherein the interval between the detection wave points in 3) is 5-10 m.

4. The method for detecting the hidden structure of the coal seam floor as claimed in claim 1, wherein the conventional preprocessing in 5) comprises establishing an observation system, removing bad tracks, reversing polarity, filtering in a one-dimensional frequency domain, analyzing frequency spectrum and analyzing energy.

5. The method of detecting the latent formations on the floor of a coal seam as claimed in claim 1 wherein the special pre-processing in 5) includes cylindrical diffusion correction, polarization rotation, two-component rotation and synthesis, dispersion analysis, time-frequency analysis and velocity analysis.

6. The method for detecting the hidden structure of the coal seam floor as claimed in claim 1, wherein the energy correction algorithm in 7) comprises the following steps:

a) making an amplitude spectrum for each seismic data, and taking 101 frequency points from 0-500Hz at intervals of 5 Hz;

b) taking out the first frequency points of all the channels, sequencing according to the offset size, performing linear regression analysis on the sequenced data, and then pulling the regression line to be horizontal, wherein the frequency points are lifted along with the regression line;

c) in the same way, the second and third frequency points of all channels are taken out until all frequency points are finished;

d) and for each channel, respectively taking the maximum value of the corrected 101 frequency points as the corrected energy value of the channel, namely finishing energy correction, wherein the corrected data is between 0 and 1.

Technical Field

The invention relates to a method for detecting a hidden structure of a coal seam floor.

Background

The most effective method of detecting formations today is seismic exploration. Three-dimensional seismic exploration techniques are typically employed at the surface, and tank wave seismic exploration techniques are employed downhole. However, the two technologies cannot solve the problem of detecting the structure below the coal seam floor well at present. The detection of the coal seam floor hidden structure has an extremely important significance for preventing and controlling water damage of the coal seam floor, in recent years, major coal seam floor water outlet accidents are almost related to the hidden structure, and the detection of the coal seam floor hidden structure is a worldwide technical problem which cannot be effectively solved so far.

Disclosure of Invention

The invention aims to solve the technical problem of overcoming the defect that the detection technology of the coal seam floor hidden structure in the prior art is relatively lagged, and provides a detection method of the coal seam floor hidden structure.

In order to solve the technical problems, the invention provides the following technical scheme:

a method for detecting a hidden structure of a coal seam floor takes a stope working face as a construction site, requires the working face to finish at least two tunneling roadways, and has a condition of transmitting to the working face, and comprises the following specific construction methods:

1) arranging shot points along one roadway and arranging wave detection points along the other roadway;

2) the arrangement position of the shot points is about 1m, such as 1m +/-0.1 m, close to the interface of the bottom plate, so that higher sliding wave energy can be obtained, the distance between the shot points is usually 5-10 m, and the distance between the shot points can be adjusted under the condition that the condition is not allowed;

3) the wave detection point is arranged at the boundary of the roadway bottom and the coal wall and is received by using a y component; the spacing between the detection points is usually 5-10 m, and the spacing between the detection points can be adjusted under the condition that the conditions are not allowed;

4) sequentially exciting one by one during blasting, receiving by adopting a fully-arranged geophone, and recording data by a gliding wave seismometer;

the data processing method comprises the following steps:

5) data preprocessing

The data preprocessing comprises conventional preprocessing and special preprocessing, wherein the conventional preprocessing is similar to the ground three-dimensional seismic exploration data preprocessing, and comprises the steps of establishing an observation system, removing bad tracks, reversing polarity, filtering a one-dimensional frequency domain, analyzing a frequency spectrum, analyzing energy and the like; the special preprocessing is mainly performed on the gliding waves, and comprises cylindrical diffusion correction, polarization rotation, rotation and synthesis of two components, frequency dispersion analysis, time frequency analysis, speed analysis and the like.

6) Extraction of gliding wave energy

The energy parameters of low-frequency channel waves, normal-frequency P waves and normal-frequency S waves are mainly used for inverting the absorption condition of the bottom plate structure, so that parameter data, namely sliding wave energy data, need to be extracted. P waves, S waves and channel waves often exist on the actual measurement underground seismic records at the same time, manual parameter pickup is carried out on the three types of waves by adopting a time window opening method, and the energy of the waves is a true amplitude energy value obtained after envelope calculation and summation of the records in the time window and formation attenuation compensation.

7) Correction of gliding wave energy

The gliding wave energy is exponentially attenuated along with the change of the offset distance, and is influenced by factors such as the excitation dose and the coupling of a detector, so that the gliding wave energy of each channel has magnitude difference, the gliding wave energy change caused by the structure is difficult to reflect, and the tomography cannot be directly carried out. Therefore, an energy correction algorithm is provided to correct the gliding wave energy difference caused by factors such as offset, excitation dose and detector coupling, and the corrected energy parameters can be directly used for tomography.

The specific algorithm comprises the following 5 steps:

a) making an amplitude spectrum for each seismic data, and taking 101 frequency points from 0-500Hz at intervals of 5 Hz;

b) taking out the first frequency points of all the channels, sequencing according to the offset size, performing linear regression analysis on the sequenced data, and then pulling the regression line to be horizontal, wherein the frequency points are lifted along with the regression line;

c) in the same way, the second and third frequency points of all channels are taken out until all frequency points are finished;

d) and for each channel, respectively taking the maximum value of the corrected 101 frequency points as the corrected energy value of the channel, namely finishing energy correction, wherein the corrected data is between 0 and 1.

8) Tomography of gliding wave energy

The tomography adopts direct ray forward algorithm and SIRT inversion algorithm, and the gliding wave energy tomography algorithm is as follows:

a) establishing a working face initial model and dividing a computational grid;

b) tracking the straight rays, namely multiplying energy by corresponding offset distance, and then distributing the energy to each grid according to the length of the rays;

c) performing inversion solution according to the difference value between the theoretical energy and the actually picked energy, and correcting the model;

d) carrying out interpolation processing on the corrected model;

e) smoothing the corrected model;

f) and repeating the four steps b to e until the model modification meets certain requirements.

The theoretical basis of the invention is as follows:

and extracting the information of the working face bottom plate from the data of the glide wave seismic exploration, thereby realizing the detection of the bottom plate hidden structure. There are two specific approaches. Firstly, the low-frequency component of the sliding wave is utilized, because the lower the frequency, the greater the depth of the sliding wave entering the surrounding rock, and the stronger the energy; secondly, by utilizing the gliding waves, the actually received gliding wave trains not only comprise the traditional gliding wave trains, namely the waves from the coal bed, but also receive the waves from the surrounding rocks, namely the top floor.

The full wavefield taxis are defined as the taxis, the sliding longitudinal waves and the transverse waves received by the actual taxis earthquake, P waves and S waves can be completely determined to be the taxis from the surrounding rock through velocity analysis and the like, namely top-bottom plate complex waves, but the energy of the bottom plate taxis can be improved through special measures such as asymmetric excitation and the like in the actual acquisition.

In the coal mine structure detection, a ground three-dimensional seismic exploration method and an underground trough wave seismic exploration method are mainly used for detection, and the two methods can effectively solve the problem of the coal seam structure at present but cannot effectively detect the hidden structure of the coal seam floor. In the coal mine water control work, the detection of the hidden structure of the coal seam floor has extremely important significance and is a difficult problem which cannot be effectively solved so far.

The invention develops research from the aspect of basic theory, designs a gliding wave detection construction method, and researches a whole set of data processing method aiming at gliding wave energy tomography, thereby realizing the detection of the hidden structure of the coal seam floor and having extremely important significance for preventing and controlling the water damage of the coal seam floor.

In the basic theory aspect, the low-frequency channel waves and the P, S waves are integrated, and all information including the bottom plate structure is fully utilized.

In the aspect of a construction method, shot points are distributed at a position which is about 1m close to the bottom plate, detectors are distributed at the boundary of the roadway bottom and the coal wall, and Y component receiving is adopted. This parameter is obtained by a number of tests.

And thirdly, in the aspect of data processing, a gliding wave energy correction method based on a probability statistical method is designed, so that the energy of the corrected gliding wave is distributed between 0 and 1 without damaging the structural information contained in the gliding wave, and the imaging of the energy analysis of the gliding wave is realized.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:

FIG. 1 is a diagram of the underlying theory of the present invention;

FIG. 2 is a single shot record after preprocessing in an embodiment of the present invention;

FIG. 3 is a three-dimensional display of different depth tomography results in an embodiment of the present invention.

Detailed Description

The preferred embodiments of the present invention will be described in conjunction with the accompanying drawings, and it will be understood that they are described herein for the purpose of illustration and explanation and not limitation.