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.In-seam 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.