Multicomponent Ionic Transport Modeling in Physically and Electrostatically Heterogeneous Porous Media With PhreeqcRM Coupling for Geochemical Reactions

Water Resources Research, Journal Year: 2019, Volume and Issue: 55(12), P. 11121 - 11143

Published: Dec. 1, 2019

Abstract Low‐permeability aquitards, such as clay layers and inclusions, are of utmost importance for contaminant transport in groundwater systems. Although most dissolved species, contaminants, surfaces charged, the role electrostatic interactions subsurface flow‐through systems has not been extensively investigated. This study presents a two‐dimensional multicomponent reactive investigation diffusive/dispersive processes homogeneous heterogeneous The proposed approach is based on multiple continua capable to accurately describe charge during ionic free water, diffuse layer, interlayer water charged porous media. layer composition simulated by considering mean potential following Donnan approach, whereas calculated adopting Gaines‐Thomas convention. Diffusive/dispersive fluxes within each subcontinuum (free interlayer) solving Nernst‐Planck equation while maintaining net zero‐charge flux. Furthermore, multidimensional flow model coupled with geochemical code PHREEQC, utilizing PhreeqcRM module, thus enabling great flexibility access all PHREEQC's reaction capabilities. benchmarked 1‐D against other software previously published experimental data. Successively, simulations performed 2‐D clayey‐sandy domains spatially variable physical properties at both laboratory field scales. results reveal that different surface charge, Coulombic impact species lead distinct spatial distribution ions subcontinua significantly breakthrough curves.

Language: Английский

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Anisotropic elastoplastic response of double-porosity media

Computer Methods in Applied Mechanics and Engineering, Journal Year: 2021, Volume and Issue: 380, P. 113797 - 113797

Published: April 7, 2021

Language: Английский

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Modified Kozeny-Carman equation for estimating hydraulic conductivity in nanoscale pores of clayey soils with active surfaces

Journal of Hydrology, Journal Year: 2023, Volume and Issue: 626, P. 130209 - 130209

Published: Sept. 26, 2023

Hydraulic conductivity is a critical parameter for studying the behavior of clay-water systems. However, accurately estimating saturated hydraulic k in clayey soil by using Kozeny-Carman (KC) equation challenging due to neglect its active surface properties and nanoscale pores. Clay surfaces can have diverse characteristics resulting from various physicochemical processes such as isomorphous substitution are typically characterized Cation Exchange Capacity (CEC). These significantly impact fluid transport through clay matrix. To address this issue, study modifies KC incorporating an adsorbed water proportion φ that considers occurrence state pore correlation with diameter, making it applicable soils. Molecular dynamics (MD) models established investigate influence interaction (CEC) nanopore size (r) on seepage flow Based MD results, specific function proposed quantify φ, which linearly related root CEC reciprocal (r), then incorporated into correction ratio k* modify classical equation. The modified validated experimental data literature, showing high R2 value 0.96. This result demonstrates extend application scope

Language: Английский

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Strength and failure characteristics of coal measures mudstone specimens containing a prefabricated flaw under true triaxial tests

Journal of Central South University, Journal Year: 2024, Volume and Issue: 31(1), P. 196 - 209

Published: Jan. 1, 2024

Language: Английский

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Phase Transition and Criticality of Methane Confined in Nanopores

Langmuir, Journal Year: 2022, Volume and Issue: 38(6), P. 2046 - 2054

Published: Feb. 4, 2022

For the first time, phase transition and criticality of methane confined in nanoporous media are measured. The measurement is performed by establishing an experimental setup utilizing a differential scanning calorimeter capable operating under very low temperatures as well high pressures to detect capillary inside nanopores. By performing experiments along isochoric cooling paths, both condensation bulk detected. pore critical point nanoconfined also determined then used derive parameters previously developed self-consistent equation state based on generalized van der Waals partition function. Using these parameters, can predict capillary-condensation curves that agree with data.

Language: Английский

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Mapping the composite nature of clay matrix in mudstones: integrated micromechanics profiling by high-throughput nanoindentation and data analysis

Geomechanics and Geophysics for Geo-Energy and Geo-Resources, Journal Year: 2024, Volume and Issue: 10(1)

Published: Aug. 14, 2024

Abstract Mudstones and shales serve as natural barrier rocks in various geoenergy applications. Although many studies have investigated their mechanical properties, characterizing these parameters at the microscale remains challenging due to fine-grained nature susceptibility microstructural damage introduced during sample preparation. This study aims investigate micromechanical properties of clay matrix composite mudstones by combining high-speed nanoindentation mapping machine learning data analysis. The approach effectively captured heterogeneity high-resolution property maps. Utilizing learning-based k -means clustering, characteristics clay, brittle minerals, well measurements on grain boundaries structural discontinuities (e.g., cracks) were successfully distinguished. classification results validated through correlation with broad ion beam-scanning electron microscopy images. resulting average reduced elastic modulus ( E r ) hardness H values for determined be 16.2 ± 6.2 0.5 GPa, respectively, showing consistency across different test settings indenter tips. Furthermore, sensitivity indentation factors was investigated, revealing limited depth tip geometry (when comparing Cube corner Berkovich a small range variations), but decreased stability lower loading rates. Box counting bootstrapping methods applied assess representativeness matrix. A relatively dataset (indentation number = 60) is needed achieve representativeness, while main challenges cover representative area characterization. Overall, this demonstrates feasibility combined analysis characterization mudstones, paving way efficient similar sedimentary rocks.

Language: Английский

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Exploring Effective Diffusion Coefficients in Water-Saturated Reservoir Rocks via the Pressure Decay Technique: Implications for Underground Hydrogen Storage

Transport in Porous Media, Journal Year: 2025, Volume and Issue: 152(2)

Published: Jan. 8, 2025

Abstract The assessment of gas diffusion in water-saturated rocks is essential for quantifying loss and determining the amount that could trigger abiotic biotic processes, potentially altering fluid rock properties. Additionally, estimating coefficients critical evaluating balance between hydrogen generation dissipation radioactive waste repositories. This investigation involved experimental determination various gases both water Bentheim, Oberkirchner, Grey Weser, Red Weser sandstones. Experimental conditions included pressures ranging from 0.2 to 1.0 MPa, consistently maintained at a temperature 35 °C. hydrogen, helium, methane were determined be 6.7·10 –9 , 9.6·10 2.8·10 m 2 /s, respectively, consistent with literature values obtained through concentration measurements without pressure gradients. However, diffusivity carbon dioxide argon was measured 10.9·10 44.6·10 significantly exceeding their corresponding by an order magnitude. discrepancy attributed significant solubility these water, resulting density-driven convection as primary transport mechanism. Furthermore, effective within analyzed specimens varied 0.8·10 2.9·10 which are higher than those dioxide, 0.3·10 0.9·10 /s. yielded diffusive tortuosity 2.6 8.2. observed positively correlated porosity, permeability, mean pore size, while exhibiting negative correlation tortuosity. Given gas–liquid mass transfer coefficient directly proportional H studying impact characteristics on microbial activity.

Language: Английский

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Mineral Erosion in Different Microstructures under ScCO₂-Water-Coal Interactions: Implications for CO₂ Sequestration in Coalbeds

Energy & Fuels, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 23, 2025

Language: Английский

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Ignoring the pre-Darcy flow phenomenon in low permeability media may lead to great deviation in contaminant transport prediction

Journal of Hydrology, Journal Year: 2025, Volume and Issue: unknown, P. 133287 - 133287

Published: April 1, 2025

Language: Английский

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Reactive solute transport simulation of multicomponent cation exchange and diffusion processes in column experiments with clay-rich rock

Journal of Contaminant Hydrology, Journal Year: 2025, Volume and Issue: 272, P. 104579 - 104579

Published: April 16, 2025

Language: Английский

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