Abstract:Based on 2-D, 3-C anisotropic elastic wave-equation staggering grid high-order finite-difference numeric simulation, the paper studied elastic wavefield in coal seam with high fractured density and azimuth anisotropic characters. The numeric simulation of elastic wavefield was carried out for the model of uniform fractural medium with different fractural density and 3-D layered model with fracture-bearing coal seam. The results showed that along with increase of fractural density (0~0.3), the elastic wavefront in dry fractural medium changed from circle to ellipsoid, while quasi-longitudinal wave from circle gradually to rhombus and quasi-shear wave from circle gradually to bow in water-saturated fractural medium. The vertical fracture only resulted in azimuth anisotropy of amplitude of reflected P-wave and converted wave on the top plate of coal seam, while in azimuth anisotropy of both amplitude and velocity of reflected P-wave and converted wave on the bottom plate of coal seam.Along with the variation of azimuths, the events of reflected P-wave and fast and slow PS-converted wave on the bottom plate of coal seam show up sine shape. The approximate linear relationship exists between the fractural density and moveout of fast with slow PS-converted wave on the bottom plate of coal seam and the amplitude of slow PS-converted wave is non-linear attenuation along with increase of fractural density.