储层特征约束频散AVO流体检测方法及应用

Reservoir characteristics constrained dispersion AVO fluid detection method and its application

以AVO方法为根本的流体识别技术,是通过求解Zoeppritz方程获得储层流体响应特征,从而实现地下储层中油气水等流体的识别技术;但直接求解Zoeppritz方程难度极大,所以学者们提出了不同形式的AVO近似方程,这些近似方程均是通过对地下地层进行一系列假设后推演而来,与Zoeppritz方程精确解存在误差,影响储层流体检测的效果和精度。基于储层特征约束的AVO反演方法,先将反射系数用一个线性通用公式来表示,再通过使用蒙特卡罗随机模拟方法构建能够反映储层信息的基函数,从而完成AVO方程的优化。将储层先验信息作为约束条件,使得该方法对储层流体的研究具有针对性,同时又保障反演流体属性的精度。将高精度时频分析与储层特征约束AVO反演方法相结合,实现了与频率相关的频散AVO反演,经应用证实该方法可进一步提高储层含流体性质检测的精度。

The fluid identification technology based on AVO method obtains reservoir fluid response characteristics by solving the Zoeppritz equation,but directly solving Zoeppritz is extremely difficult.Therefore,scholars have proposed different forms of AVO approximate equations.However,these approximate equations are based on a series of assumptions,and there are errors with the accurate solution of Zoeppritz equation,which affects the effectiveness and accuracy of reservoir fluid detection.The AVO inversion method based on reservoir feature constraints first represents the reflection coefficient with a linear universal formula,and then constructs a basis function that can reflect reservoir information by using Monte Carlo random simulation method,thereby completing the optimization of the AVO equation.The prior information of the reservoir serves as a constraint condition,making this method targeted in the study of reservoir fluids while ensuring the accuracy of inverting fluid properties.Combining high-precision time-frequency analysis with AVO inversion method constrained by reservoir characteristics,the frequency related dispersion AVO inversion is realized,which further improves the accuracy of reservoir fluid property detection.