Transmission slot wave adjacent channel amplitude ratio imaging method for concealed structure in coal face

Abstract

The invention discloses a transmission slot wave adjacent channel amplitude ratio imaging method for a concealed structure in a coal face. The transmission slot wave adjacent channel amplitude ratio imaging method comprises the following steps that the coal face is divided into N grids, and the structure attenuation coefficient of each grid is ();the propagation length of each ray path on each grid is calculated; common shot point adjacent channel transmission slot wave amplitudes are extracted by using an improved S transform discrete algorithm, a linear equation set solved by sum is calculated, and the equation set is solved by using an algebraic reconstruction method, a joint algebraic reconstruction method or a joint iterative reconstruction method to obtain the system; and structure attenuation coefficient imaging is carried out on the coal face, and structure distribution in the coal face is determined according to abnormity.

Description

technical field [0001] The invention relates to the technical field of coal mining, in particular to a transmission channel wave attenuation imaging method for concealed structures in a coal mining face. Background technique [0002] In the process of coal mining, due to the complex geological conditions of the coal seam, a large number of small-scale geological structures with a scale similar to the thickness of the coal seam, such as faults and collapse columns, are developed inside the coal seam. The traditional ground detection method has insufficient resolution and cannot accurately identify small structural anomalies in the coal seam. . The hidden unknown small-scale structural anomaly in the coal mining face has become a disaster hazard and seriously affects the coal mining operation. Transmission channel wave attenuation imaging is an effective method for detecting concealed structures in coal mining faces, and has the advantages of large detection distance and high...

AI Technical Summary

Problems solved by technology

[0026] 1. Due to the strong dispersion characteristics, the amplitude of the channel wave along the ray path is not a pure attenuation process. Within a certain distance from the source, the amplitude of the channel wave increases with the propagation distance instead of attenuation. The attenuation law of the transmitted channel wave is different from that of the non-frequency wave. Dispersive or weak dispersion body wave attenuation law, the conventional amplitude attenuation imaging method is not suitable for dispersion wave amplitude attenuation imaging;

[0027] 2. The conventional amplitude-attenuation imaging method needs to accurately obtain the initial amplitude of the transmitted channel wave excited by the seismic source, but it is impossible to accurately record the initial amplitude of the channel wave in the on-site channel wave detection;

[0028] 3. Conventional amplitude attenuation imaging requires that the initial amplitude of the channel wave excited by all shot points be consistent, but the channel wave excited by each source cannot be kept consistent due to the inconsistency of the excitation dose, blast hole depth and blasting mud sealing effect of each shot point during field detection. The initial amplitude is difficult to keep consistent;

[0029] 4. Conventional amplitude attenuation imaging methods cannot eliminate the impact of amplitude attenuation on structural imaging caused by factors that have nothing to do with structure, such as coal seam absorption attenuation, wave front diffusion attenuation, dispersion attenuation, channel wave energy leakage attenuation to roof and floor, etc.

During the imaging process, the initial amplitude was obtained by an estimation method without error constraints; the energy difference of the channel wave excited by different shot points was not accurately corrected; no corresponding measures were taken to eliminate the absorption attenuation of the coal seam, the wave front diffusion attenuation, the dispersion attenuation, The impact of the amplitude attenuation caused by factors not related to the structure such as the energy leakage attenuation of the channel wave to the top and bottom plates, so it is difficult to guarantee the imaging accuracy

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