Digital core approach to the effects of clay on the electrical properties of saturated rocks using lattice gas automation

Clay has a significant influence on the relationship between resistivity index I and water saturation Sw （i.e, I-Sw relationship） of reservoir rocks because it complicates the current paths of these rocks. It is difficult to reveal the physical mechanisms of these clay effects on the conductivities of various rocks by physical laboratory measurements because the pore structure, micro distribution and content of clay inside a rock can not be observed and controlled during the experiments. We present a digital rock approach to study these clay effects on the electrical transport properties of reservoir rocks at pore scale using lattice gas automation （LGA） method. The digital rock samples are constructed with the information of grain size distribution from SEM images of reservoir rocks. The LGA is then applied on these digital rocks fully saturated with fluids to simulate the electrical transport properties for revealing the effects of volume and distribution patterns of clay on the non-Archie behaviors of the I-Sw relationship. The very good agreement between the simulated results and the laboratory measurements clearly demonstrates the validity of the LGA in numerical research of rock physics. Based on these studies, a new model has been developed for quantitatively describing the relationship between the saturation exponent and the volume of clay （Vsh）. This development may improve the evaluation for the fluid saturations in reservoir rocks.

克莱在在抵抗力索引之间的关系上有重要影响我和水浸透 Sw (即， I-Sw 关系) 水库岩石因为它复杂化这些岩石的当前的路径。因为在岩石内的泥土的毛孔结构，微分发和内容不能在实验期间被观察并且控制，由物理实验室大小在各种各样的岩石的传导性上揭示这些泥土效果的物理机制是困难的。我们在场在水库的电的运输性质上学习这些泥土效果的一条数字岩石途径用格子气体在毛孔规模摇自动化(LGA ) 方法。数字岩石样品从水库岩石的 SEM 图象与谷物尺寸分发的信息被构造。LGA 然后充分在这些数字岩石上被使用与液体浸透了为在 I-Sw 关系的非高射炮行为上揭示体积的效果和泥土的分发模式模仿电的运输性质。在模仿的结果和实验室大小之间的好协议清楚地在岩石物理的数字研究表明 LGA 的有效性。把研究基于这些，一个新模型为描述在浸透代表和泥土的体积之间的关系的份量上被开发了(V 嘘) 。这开发可以在水库岩石中为液体浸透改进评估。