等效流体体积模量直接反演的流体识别方法

Fluid identification based on direct inversion of equivalent fluid bulk modulus

流体因子构建对储层流体识别具有重要意义。基于等效介质理论,将体积模量中体现流体效应的部分定义为等效流体体积模量。岩石物理分析表明,等效流体体积模量对于岩石孔隙内流体类型更加敏感,叠前地震反演可以有效获得等效流体体积模量。借助多孔弹性介质岩石物理模型,建立了Gassmann流体项与等效流体体积模量的直接关系,推导了基于等效流体体积模量的Zoeppritz方程的近似方程以及弹性阻抗方程,实现了基于弹性阻抗的等效流体体积模量直接反演。模型试算验证了方法的可行性,实际资料应用表明基于等效流体体积模量直接反演提高了流体识别准确度。

Fluid factor is important for reservoir fluid identification, equivalent fluid bulk modulus is more sensitive to different types of fluid within the pores of rock than conventional fluid factor. Pre-stack seismic inversion can effectively get equivalent fluid bulk modulus. With porous elastic medium petrophysical model, a direct relationship between equivalent fluid bulk modulus and Gassmann fluid is established. The Zoeppritz approximate and elastic impedance equations are derived. Direct inversion is realized based on elastic impedance equation of equivalent fluid bulk modulus. Model test verifies the feasibility of the method, the actual data inversion indicates that the method improves the accuracy of fluid identification. © 2017, Editorial Department OIL GEOPHYSICAL PROSPECTING. All right reserved.