煤层反射槽波三维正演模拟

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

煤炭资源是我国重要的基础能源。我国煤矿开采地质条件较为复杂,随着煤田开采深度及强度不断加大,对煤田微幅构造精细探测的需求日益增加。槽波勘探技术因其探测精度高、抗干扰能力强、波形特征易于识别等优点,是目前获取煤层工作面精细地质构造信息的有效勘探手段。但井下煤层中的波场复杂,反射槽波的波场特征尚待深入研究。本文对煤矿井下三维槽波数值模拟技术进行研究,设计不同类型的含断层三维煤层地质模型,采用三维交错网格高阶有限差分算法模拟反射槽波,分析了反射槽波的波场特征,探讨了不同倾角以及不同断距断层对反射槽波的影响。通过切除干扰波技术,获得有效反射槽波,进而对反射槽波的同相轴进行包络叠加处理,较好地压制了槽波的频散,同相轴明显收敛,能量更为集中,为后续成像处理提供了良好的数据基础。

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.