裂缝各向异性介质中P-SV转换波正演模拟

Forward modeling of P-SV wave in fractured anisotro-py medium

石油大学地球资源与信息学院,山东东营 257061

Geo-Resources and Information Institute, University of Petroleum, Dongying 257061, China

裂缝介质正演是研究裂缝性油藏的各向异性、裂缝检测方法、裂缝AVO反演等的前提。在裂缝方位各向异性(EDA)介质模型的基础上,重点研究了纵波震源激发的地震波所产生P-SV波的有限差分正演模拟方法。从各向异性单斜对称系统的刚性矩阵推导出的波动方程,可以满足EDA介质模型不同方位角入射的二维差分模拟要求。在有限差分模拟中,采用了普通的Kelly差分格式、二阶各向异性吸收边界条件和一般的纵波震源的解析形式,并应用修正的通量传输校正(FCT)方法来消除频散。同时,对纵波震源的解析式进行了技术处理,取得了较好的效果。

Forward modeling in fractured medium is the premise which research into fractured anisotropy, fracture detecting methods and AVO inversion. Based on EDA theoretic model in fractured anisotro-py, this paper emphasizes on the finite difference modeling method that only produce P-S wave through P-wave source. Wave equations, which were derivate from the stiffness Matrix of anisotropy monocline symmetry system, may meet different azimuth modeling of 2-D finite difference. The general Kelly difference format, 2nd anisotropy absorbing boundary conditions and the common analytic solution of P-wave are applied during the process of modeling. FCT method is to eliminate disperse, and put forward to technique on P-wave source denotation.