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AVO分析是目前地震勘探潜在油气储层的一个重要方法。体散射信息包含了层结构、岩性和孔隙流体信息,对地震勘探非常有用。但是基于 Zoeppritz方程的传统AVO分析之只包含了单层信息。薄层厚度定量解释对构造解释、储层描述和储层横向预测都非常重要。本文阐述的基于频率域弹性传播矩阵反射系数谱方法既考虑了层界面引起的振幅变化(Zoeppritz方程),也考虑了层内传播引起的振幅变化。因此该反射系数谱既包括单一层界面信息,也包括层内体散射信息。该反射系数谱是层厚和频率的连续函数,便于分析频率和层厚对反射系数谱的影响。可分析的薄层厚度可以无限小,直至消失。可分析的频率是任意的和连续的。这是对时间域反射系数做傅里叶变换无法实现的。地震波的传播是复杂的,各种波型是同时存在而且相互转换的,该反射系数谱考虑了各种波型在传播过程中的相互转换以及多次波。与比射线方法比更便于正演薄层多波多分量AVO响应。
AVO analysis is currently an important method of seismic exploration of potential oil and gas reservoirs. Volume scattering information contains layer structure, lithology, and pore fluid information that is useful for seismic exploration. However, the traditional AVO analysis based on the Zoeppritz equation only contains single-layer information. The quantitative interpretation of thin-layer thickness is very important for tectonic interpretation, reservoir description and reservoir lateral prediction. In this paper, the method based on the frequency domain elastic propagation matrix reflection coefficient spectrum is not only considered the Zoeppritz equation induced by layer interface, but also takes into account the amplitude variation caused by propagation in the layer. Therefore, the reflection coefficient spectrum includes both single-layer interface information and intra-layer bulk scattering information. The reflection coefficient spectrum is a continuous function of layer thickness and frequency, facilitating the analysis of the influence of frequency and layer thickness on the reflection coefficient spectrum. The thin layer thickness that can be analyzed can be infinitely small until it disappears. The frequencies that can be analyzed are arbitrary and continuous. This is a Fourier transform of the time domain reflection coefficient can not be achieved. The propagation of seismic waves is complex, and the waveforms are co-existing and interconverted. The reflection coefficient spectrum takes into account the interconversion and multiples of various waveforms during propagation. Compared with the ray method is more conducive to forward multi-wave multi-component multilayer AVO response.