While the electrical conductivity of smectite-rich rocks is high, previous studies have only partially revealed its dependence on temperature, salinity, and porosity. This knowledge gap mainly arises from challenges in controlling various experimental conditions when measuring the conductivity of real smectite-bearing rock samples and quantifying the smectite content. To mimic conductivity measurements under ideal conditions, this study aimed to develop a simulator capable of accurately configuring the conditions to predict the direct-current conductivity of saturated rocks composed of an aqueous NaCl solution, quartz, and smectite under various temperatures (20°C–200°C), salinities (10⁻⁴–5 mol kg⁻¹), porosities (0–1), and smectite fractions (0–1). The simulator reproduced the experimental conductivity measurements from drilled core samples by giving the anisotropy of those components' distribution. In addition, simulations with randomly assigned components revealed that when rocks contain abundant smectite, the bulk conductivity partially decreases with increasing NaCl solution's salinity or volume fraction. These negative slopes were approximated using empirical equations derived from previous studies. Percolation analysis further revealed that when the components are randomly assigned, conductive paths begin to form between the ends of the modeled sample once the sum of the volume fraction of bulk pore and smectite reaches 0.1.

中文翻译：

---

含 NaCl 溶液、石英和蒙脱石的三元混合物电导率的数值模拟


虽然富含蒙脱石的岩石的电导率很高，但以前的研究只部分揭示了它对温度、盐度和孔隙度的依赖性。这种知识差距主要是由于在测量真实含蒙脱石的岩石样品的电导率和量化蒙脱石含量时，在控制各种实验条件方面的挑战造成的。为了模拟理想条件下的电导率测量，本研究旨在开发一种模拟器，该模拟器能够准确配置条件，以预测由氯化钠水溶液、石英和蒙脱石组成的饱和岩石在不同温度 （20°C–200°C）、盐度 （^10-4-5 mol ^kg-1 ） 下的直流电导率）、孔隙度 （0-1） 和蒙脱石馏分 （0-1）。该模拟器通过给出这些组分分布的各向异性，再现了钻孔岩心样品的实验电导率测量值。此外，使用随机分配成分的模拟表明，当岩石中含有丰富的蒙脱石时，体电导率随着 NaCl 溶液的盐度或体积分数的增加而部分降低。这些负斜率是使用从先前研究中得出的经验方程进行近似计算的。渗流分析进一步表明，当成分随机分配时，一旦块孔隙和蒙脱石的体积分数之和达到 0.1，导电路径就会开始在建模样品的末端之间形成。