地层条件下煤层顶、底板声波速度与反射特征

采取淮南矿区主采煤层13－1煤及其顶、底板典型泥岩与砂质泥岩样品，通过改变温度与压力来模拟地层条件，测试获得煤岩层声波速度随深度（400～1 200 m）的变化，并分析不同深度下煤层顶、底板反射系数与入射角的变化关系.结果表明：煤岩层声波速度随深度增加而增大，且具有较好的对数相关性；煤层顶、底板反射系数不仅随入射角变化而变化，而且受煤层埋深和顶、底板岩性变化的影响，随着煤层埋深增加,其顶、底板反射系数绝对值均减小，煤层顶、底板岩石波阻抗差异越大，反射系数越大，因此，在进行煤田或矿井地震勘探设计与资料处理时，应综合考虑勘探区内煤层顶、底板岩性分布与赋存深度变化，以便有效地利用顶、底板反射P-P波和P-S波AVO信息来解决诸多矿井地质条件精细探测问题.

Reflection characteristics and acoustic velocity of coal roof and floor under formation conditions

Typical roof and floor mudstone and sandy mudstone were sampled from the No13-1 coal seam in Huainan mining area and acoustic velocity were tested under the formation conditions by changing temperature and pressure with the depth (400~1 200 m). Also, the relationship between reflection coefficients and the changes of incident angles in coal roof and floor with different depths were analyzed. The results show that acoustic velocity of coal and rock strata increases with depths and have good logarithm correlation. The reflection coefficients of roof and floor are not only changed with the incident angles, but also are effected by the depths and the lithology of coal roof and floor. With increasing buried depths of coal seam, the absolute values of reflection coefficients all decrease. When wave impedance difference of coal roof and floor is bigger, its reflection coefficients are bigger. Therefore, lithologic distribution and depth of coal roof and floor should be comprehensively considered in order to use AVO information of reflective P-P wave and P-S wave to solve the detailed detection problems under lots of geological conditions of coal mine in exploration areas when the design of coal seismic prospecting and data processing are made.