适于Russell流体因子提取的孔隙弹性介质反射系数近似方程

A reflection coefficient approximation equation of poroelastic media for Russell fluid factor estimation

Russell流体因子是表征储层孔隙流体特征的重要敏感流体因子,其提取结果的可靠性是决定流体判识质量的核心问题之一。叠前地震反演是提取流体因子的主要途径,而反射系数近似方程是叠前反演的基础。结合Biot-Gassmann多孔弹性介质理论对反射系数近似方程进行了重新推导,得到了包含Russell流体因子的孔隙弹性介质反射系数线性近似方程;通过分析方程的精度和反演敏感特征,验证了新反射系数近似方程的可靠性和Russell流体因子项的高反演敏感度;最终基于贝叶斯反演框架的AVO反演实现了Russell流体因子的定量提取。模型试算和实际应用结果表明,基于新反射系数近似方程的叠前反演方法能够稳定可靠地从地震资料中提取Russell流体因子,为储层流体识别提供了一种新的流体因子计算方法。

The Russell fluid factor is an important sensitive parameter for reservoir pore-fluid identification and the estimation techniques for Russell fluid factor plays a key role to the quality of reservoir fluid identification.The prestack seismic inversion based on the reflection coefficient approximation equation is the main approach to estimate fluid factors.With the help of Biot-Gassmann poroelastic theory,the Aki-Richards reflection coefficient approximation is rearranged to get a new linear approximation equation containing the Russell fluid factor parameter.Analytical analysis is carried out to check the accuracy and inversion sensitivity of the new approximation equation,which shows the reliability of the new reflection coefficient approximation and high inversion sensitivity of Russell fluid factor term.Finally,the directly quantitative inversion of pore-fluid impedance is realized based on the Bayesian AVO inversion.The model test and real application denote the feasibility and stability of this Russell fluid factor estimation technique.This is proposed as a new fluid estimation approach for reservoir fluid identification.