地震分频AVO方法研究现状与展望

Research Progressing on Frequency Dependent AVO Analysis

传统的AVO理论只考虑单界面两边的岩石物理特性,没有考虑地层厚度、其他波场以及油气藏中地震波的能量衰减和速度散射,在实际应用中还存在很多未解决的问题。实际地震波信息常常是地下多个砂泥岩薄互层的综合响应,每个薄层产生的地震反射信号经傅里叶变换后,在频率域都有一个与之相对应的特定频率成分,且这种频率成分在频率域是唯一的。将分频技术与AVO研究密切结合是有效解决薄互层气藏地震AVO识别的有效途径之一。简要介绍了AVO技术及传统AVO技术存在的问题,讨论了地震AVO与地震频率的关系,指出进行分频AVO分析的依据,并进一步讨论了时频分析方法。

Traditional AVO theory only focuses on the petrophysical characteristics of two sides of an interface in spite of the layer thickness and other wave fields as well as attenuation and dispersion of seismic waves in reservoir so that there are many problems in the actual application of the technique. Seismic waves are the comprehensive responses of several thin sand/shale interbeds. After Fourier transformation, the reflective wave from each thin bed will respond to a specific frequency component, which is unique in frequency domain. By combining the spectral decomposition and AVO technique, this study on the frequency dependent AVO will be one of the effective tools in solving the seismic AVO identification issue in a thin interbed gas reservoir. A brief introduction of AVO technology is given while the problems in traditional AVO analysis are illuminated. The relationship between seismic AVO and frequency is discussed and the reason of frequency dependent AVO analysis is indicated. The time-frequency analysis method is also discussed.