含裂隙煤层的地震记录模拟

Seismic record simulation for coal-seam containing fractures

采用线性滑移(Linear Slip Deformation)裂隙介质模型、各向异性弹性波模拟方法,对含裂隙煤层进行了2D2C(二维二分量)单炮记录模拟与分析。结果表明:煤层含裂隙后与不含裂隙时相比,反射时差的变化已不足以识别,但由于波速的改变会使煤层顶底界面的波阻抗发生变化,从而引起波的动力学特征的改变,AVO现象尤其明显。当裂隙为非垂直时,炮点两侧的反射波能量和振幅出现不对称现象。x分量和z分量的特征明显不同,转换波主要记录在x分量上,横波在x分量上有不可忽视的能量。因此,应用各向异性理论、利用多分量转换波研究煤层裂隙的特征是可能的。

Through using Schoenberg linear slip deformation model in fracture medlar and adopting the simulation method of anisotropy elastic wave, 2D2C seismic record was simulated to the coal- seam in fracture media. And the simulation result was discussed. In result , the coal- seam containing fractures was compare with the one not containing fractures, the surge impedance of boundary plane in coal-seam top and bottom is made changes by reason of the changes of wave velocity, whereby the changes of dynamics distinction to the wave. The AVO phenomenon is obvious. The energy and amplitude of reflected wave in the shot point bilateral appears dissymmetry. The characteristics of x component and z component is different visibly. The shear wave in x component has in - inobservant energy. Wherefore it is possible that coal - seam fracture is detected using anisotropy theory and muticomponent converted wave.