Study on 3D forward modeling of reflected in-seam wave in coal seam

Coal is important energy resource for China with complex mining conditions. With the increasing of mining depth and intensity, the demand for fine detection of coalfield micro-structure is increasing. Inseam wave exploration technology is an effective means to obtain the fine geological structure information of coal seam working face because of its advantages of high detection accuracy, strong anti-interference ability and easy identification of waveform characteristics. However, the seismic wavefield in underground coal seam is complex, and the wavefield characteristics of reflected in-seam wave need further study. In this paper, we study the 3D in-seam wave numerical simulation technology in underground coal mines. Different types of 3D coal seam geological models with faults are designed, and the reflected in-seam waves are simulated by 3D staggered grid high-order finite difference algorithm. The wavefield characteristics of reflected in-seam waves are analyzed, and the influences of faults with different dip angles and different fault distances on reflected in-seam waves are discussed. The effective reflected in-seam wave is obtained by removing the interference wave technology, and then the reflected in-seam wave is processed by envelope superposition. The dispersion of in-seam wave is suppressed effectively, the event converges obviously, and the energy is more concentrated, which provides a good data basis for the subsequent imaging processing. © 2024 Geological Society of China. All rights reserved.