基于数字岩心研究流体性质对裂缝性低渗透储层弹性参数的影响规律

为研究裂缝及流体性质对低渗透储层弹性参数的影响规律,采用X射线CT扫描技术构建低渗透储层岩石的3维数字岩心,应用图像处理算法加入定向排列的平行便士状裂缝,形成横向各向同性数字岩心,采用扩展的有限元方法计算含有裂缝的数字岩心的弹性模量,分析裂缝及流体性质对其弹性模量的影响规律。结果表明:裂缝纵横比和密度保持不变,随流体体积模量的增加,纵波各向异性参数呈线性趋势减小;裂缝密度和流体性质不变,随裂缝纵横比增加,储层岩石的弹性模量均呈线性增加;裂缝纵横比和流体性质不变,随裂缝密度增加,储层岩石的弹性模量也呈线性减小。

Research of influence laws of fluid properties on elastic parameters of fractured low permeability reservoir rocks based on digital core

In order to investigate the effects of fracture and fluid properties on the elastic parameters of fractured low permeability reservoirs, the digital cores of low permeability reservoirs were constructed by X-ray CT. The transversely isotropic digital cores with parallel penny shape cracks were firstly constructed using digital image processing technology, then the elastic parameters of the cores were calculated by an extended finite element method, and lastly the effects of fracture and fluid properties on the elastic modulus were studied. The results show that with fixed crack aspect ratio and density, the longitudinal wave anisotropy linearly decreases with the increase of the fluid bulk modulus. With fixed crack density and fluid properties, the elastic moduli of fractured low permeability reservoir rock show a linear relationship with increasing crack aspect ratio. And with fixed crack aspect ratio and fluid properties, the elastic moduli of fractured low permeability reservoir rock show a linear relationship with increasing crack density.