VTI型构造煤AVO正演模拟

通过对原生煤、构造煤、软分层构造煤和VTI型构造煤的P波AVO的正演模拟，探讨上述多种煤层岩性的可探测性.对于厚煤层来说，通过Zoeppritz方程获得了原生煤、构造煤和软分层构造煤的P波AVO曲线.对于厚层的VTI型构造煤，首先利用等效介质理论求出其刚度矩阵，再利用基于各向异性理论的传播矩阵法求解出其P波AVO曲线.在此基础上，通过和地震子波的褶积获得合成地震记录，同时对薄煤层的AVO曲线和合成地震记录进行了正演模拟.发现当煤层为厚煤层时，煤层顶板反射P波的AVO曲线为IV类AVO，并且不同类型煤层间的AVO曲线斜率和截距差别较大.当煤层是薄煤层时，煤层反射波是复合波.此时，原生煤和普通构造煤的反射波振幅较小，AVO曲线具有较明显的IV类AVO特征；而软分层构造煤和VTI型构造煤的反射波振幅较大，AVO曲线变化剧烈.因此，通过AVO技术可以定性识别原生煤、普通构造煤、软分层构造煤和VTI型构造煤.

AVO forward modeling for VTI coal

Discussed the possibility of prospecting primary coal,tectonic coal,soft coal and VTI coal by P-wave AVO forward modeling.For thick coal bed,the P-wave AVO curves of primary coal,tectonic coal,soft coal were achieved by Zoeppritz equation.For thick VTI coal bed,calculated its stiffness matrix by effective media's theory at first;and then,computed the P-wave AVO curve of this coal by propagation matrix method which based on anisotropy theory.On the basis,synthetic seismogram was gotten by convolving seismic ...