{"title":"Numerical Simulation on the Electrical Conductivity of Ternary Mixtures Containing NaCl Solution, Quartz, and Smectite","authors":"K. Aoyama, T. Hashimoto","doi":"10.1029/2024JB029063","DOIUrl":null,"url":null,"abstract":"<div>\n \n \n <section>\n \n <p>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<sup>−4</sup>–5 mol kg<sup>−1</sup>), 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.</p>\n </section>\n </div>","PeriodicalId":15864,"journal":{"name":"Journal of Geophysical Research: Solid Earth","volume":null,"pages":null},"PeriodicalIF":3.9000,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JB029063","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Geophysical Research: Solid Earth","FirstCategoryId":"89","ListUrlMain":"https://onlinelibrary.wiley.com/doi/10.1029/2024JB029063","RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"GEOCHEMISTRY & GEOPHYSICS","Score":null,"Total":0}
引用次数: 0
Abstract
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.
期刊介绍:
The Journal of Geophysical Research: Solid Earth serves as the premier publication for the breadth of solid Earth geophysics including (in alphabetical order): electromagnetic methods; exploration geophysics; geodesy and gravity; geodynamics, rheology, and plate kinematics; geomagnetism and paleomagnetism; hydrogeophysics; Instruments, techniques, and models; solid Earth interactions with the cryosphere, atmosphere, oceans, and climate; marine geology and geophysics; natural and anthropogenic hazards; near surface geophysics; petrology, geochemistry, and mineralogy; planet Earth physics and chemistry; rock mechanics and deformation; seismology; tectonophysics; and volcanology.
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