各向异性介质中的AVO

AVO in anisotropic media

清华大学工程力学系, 北京100084

Department of Engineering Mechanics, Tsinghua University, Beijing 100084

本文分析了包括横向各向同性和方位各向异性在内的各向异性介质的成因, 以及它们广义的和各自的本构关系。由此讨论了弹性波在两种各向异性介质中的传播特点, 并提出了表征各向异性程度的广义各向异性参数, 这些参数既可表征横向各向同性介质的各向异性, 也可表征方位各向异性介质的各向异性。本文特别讨论了两种各向异性介质中存在水平界面时的反射系数, 并将Dely等人推导的横向各向同性介质中的反射系数公式推广到方位各向异性主轴上。根据算例讨论了修正的Banik和Thomsen的近似式, 着重讨论和分析了两种各向异性介质中的AVO关系以及对实际勘探的影响和指导意义。

The cause of anisotropy, including transverse isotropy and azimuthal anisotropy, is analyzed in this paper. Its generalized and respective constitutive relatioaship is also given. After discussing the characteristics of elastic wave propagating in thase two kinds of ansotropic media, we Put forwar the generl-ized Ansotropy parametere which describe the anisotropy degree for both transvarely isotorpic media and azimuthal anisotropic media. Speial discuss is held on the reflection effciens when existing horizontal interface in thase two kinds of anndropic media. The reflection whcien formla derived by Dely et al. for transvewly iwtropic media is extended to the Principal bos for azimuthal anisotropic media. Through computational examples, we discuss the medified Banik’s and Tomsen’s approximation for mulas. Finally, we discuss and analyze AVO in these two kinds of anisotropic media and its influence on ha and its influence onactual exploration.