等效双孔介质电-声曲折度分析及其与弹性参数的关系

Analysis of Electrical-acoustic Tortuosity of Equivalent Dual Porosity Media and Its Relationships with Elastic Parameters

针对复杂的多孔介质岩石孔隙结构,提出等效双孔介质理论将岩石等效成双孔柱状模型,结合宏观欧姆定律得到岩石的电曲折度和电学参数;采用线性欧拉公式求解一维波动方程得到声曲折度,研究电曲折度与声曲折度的关系;分析孔隙度与孔隙组分比对岩石曲折度的影响,并通过实验分析曲折度与体积模量、剪切模量的关系。电曲折度与声曲折度在本质上是一致的,均反映了岩石的孔隙结构;曲折度主要受控于孔隙组分比且不同孔隙组分比范围内岩石的曲折度变化趋势不同;曲折度与岩石的体积模量、剪切模量等弹性参数有良好的线性关系。

To describe the complex rock pore structure of porous media, proposed is the theory of equivalent dual porosity media that the rock can be equivalent to the cylindrical dual-porosity model. And subsequently the electrical tortuosity and electrical parameters are obtained from macroscopic Ohms law. Researched is the relation between electrical tortuosity and acoustic tortuosity which is obtained from solving one-dimensional wave equation based on the linear Euler formula. Moreover, the effect of porosity and different pore components on the rock tortuosity is studied and the relation among tortuosity, bulk modulus and shear modulus is further analyzed by experiments. The above research shows both electrical tortuosity and acoustic tortuosity are consistent essentially, therefore reflecting the rock pore structure. The tortuosity is mainly controlled by the ratio of pore component and its change trend varies with different ranges of ratio. Besides, the tortuosity has good linear relation with elastic parameters, such as bulk modulus and shear modulus.