不同煤岩介质模型的波场特征研究

准确和形象地分析煤矿微地震波在不同介质中的传播规律，能够为煤矿主动地震勘探以及反演煤矿不同区域内部介质结构提供有效的理论依据。基于二维介质模型，以煤矿典型的煤、岩单一均匀介质模型、煤岩组合多层介质模型、含断层煤岩介质模型以及含水煤岩双相介质模型为例，利用高阶有限差分法对不同煤岩介质进行了波场模拟，分析不同介质的波场特征。研究结果表明，高阶有限差分法可以准确、形象地得到煤岩不同介质条件下的纵横波的波场特征；不同介质模型的波场特征各不相同，在多层煤岩介质中不同介质的分界面会发生纵横波的反射、透射和转换，产生透射波、透射转换波、反射波和反射转换波；在含断层煤岩介质中断层处不仅可以产生透射波、透射转换波、反射波和反射转换波，还可以发生绕射产生绕射波；在含水煤岩双相介质中不仅有快纵波和横波，也会产生慢纵波。不同时刻的波场快照可以进一步形象地描述波场动态特征，都为矿山微震波场分析打下了理论基础。

Study on wave field characteristics of different media models of coal and rock

Accurately and vividly analyzing the propagation law of microseismic wave in different media of coal and rock can provide strong theoretical basis for active seismic exploration in the coal mine and the inversion on the media structure in the different regions. In this paper, based on two-dimensional media models in the coal mine, including the general homogeneous medium model of coal/rock, the multi-media model combing the coal and rock, the fault-bearing medium model of coal and rock and water-bearing two phase medium model of coal and rock, the wave field simulations of different media above are carried out using the high-order finite-difference method and the wave field characteristics are analyzed. The results show that the high-order finite difference method is powerful in accurately obtaining the wave field characteristics of P- and S-wave in different media models. Different wave field characteristics appear in different media models. In the multi-layered media of coal and rock, the reflection, transmission and transition of P and S wave occur at the interfaces of different media, and the transmissive wave, the transmitted converted wave, the reflected wave and the reflected converted wave appear. In the fault-bearing media model of coal and rock, not only the transmissive wave, the transmitted converted wave, the reflected wave and the reflected converted wave can occur , but also the diffracted wave can appear at the fault. In the water-bearing two-phase medium model of coal and rock, not only the fast P-wave and shear-wave, but also the slow P-wave can occur. The snapshots of the wave field at different time can further vividly describe the dynamic characteristics of the wave field, and they can provide the theoretical foundation for analyzing the micro-seismic wave field in the coal mine.