据Chapman（2003）对速度频散的新认识，受地震反射界面两侧频散性质差异的影响，反射系数将随频率改变而改变，即反射系数是以入射角、物性参数和频率为变量的函数。由此，项目针对致密砂岩气藏储层预测、含气性识别等难点与热点问题，利用多尺度裂缝介质模型中物性参数具有频变特征的优势，基于Zoeppritz简化方程建立反射系数与频率之间的数学关系，推导出截距、梯度、碳氢检测因子、流体检测因子、拟泊松比等AVO属性与频率之间的数学关系，进一步发展AVO理论。基于多尺度裂缝介质正演模拟、多子波分解与重构等技术，深刻分析各种含气模型的频变AVO地震响应特征，以建立系统的频变AVO含气性识别模式；并通过反演获取具有频变特征的AVO属性，最终创建一套先进、实用的含气性识别新方法。拟将该方法应用于四川盆地西部深层致密砂岩气藏的勘探开发中，为解决储层预测、含气性识别等世界级复杂难题提供支撑。

In 2003,Chapman.M.published articles in well-known journals in which proposed the view of velocity frequency dispersion, that because of the frequency dispersion difference between both sides of interface, reflection coefficients of seismic wave will change with frequency, and the equation of reflection coefficients can be expressed as function of incident angle and frequency. Based on Chapman's viewpoint, this project will aim at the tight sandstone gas reservoir, apply the frequency dependent characters of matter parameters in multi-scale fracture models, derivate function between reflection coefficients and frequency, and function of frequency dependent AVO inversion, build the mathematic relationship between AVO inversion attributes and frequency, such as intercept, gradient, hydrogen detection factor, liquid detection factor, pseu-poisson ratio. The aim of project is to develop AVO theory. By using technologies of multi-scale fracture modeling and multi-wavelet decomposition and reconstruction, analyze and summarize the frequency dependent characters of different gas models to build systemic frequency dependent AVO gas response modes, and acquire frequency dependent AVO attributes from inversion, to establish an advanced and practical gas detection method. This new method will be used in deep tight sandstone gas reservoir in the west of Sichuan basin to provide achievements for reservoir recognition and gas detection.