Comparative Study of Water Flow in Nanopores with Different Quartz <inline-formula><math display="inline"><semantics><mrow><mrow><mo stretchy="false">(</mo><mn>10</mn><mover><mn>1</mn><mo>¯</mo></mover><mn>0</mn><mo stretchy="false">)</mo></mrow></mrow></semantics></math></inline-formula> Surfaces via Molecular Dynamics Simulations

Dewatering and gas production are applied on a large scale in shale gas development. The fundamental mechanisms of water flow in shale nanoporous media are essential for the development of shale oil and gas resources. In this work, we use molecular dynamic simulations to investigate water flow in tw...

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Main Authors: Peng Zhou, Junyao Bao, Shiyuan Zhan, Xingjian Wang, Shaopeng Li, Baofeng Lan, Zhanbo Liu
Format: Article
Language:English
Published: MDPI AG 2025-06-01
Series:Nanomaterials
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Online Access:https://www.mdpi.com/2079-4991/15/12/896
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Summary:Dewatering and gas production are applied on a large scale in shale gas development. The fundamental mechanisms of water flow in shale nanoporous media are essential for the development of shale oil and gas resources. In this work, we use molecular dynamic simulations to investigate water flow in two different quartz surface (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mrow><mo stretchy="false">(</mo><mn>10</mn><mover><mn>1</mn><mo>¯</mo></mover><mn>0</mn><mo stretchy="false">)</mo><mtext>-</mtext><mi>α</mi></mrow></mrow></semantics></math></inline-formula> and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mrow><mo stretchy="false">(</mo><mn>10</mn><mover><mn>1</mn><mo>¯</mo></mover><mn>0</mn><mo stretchy="false">)</mo><mtext>-</mtext><mi>β</mi></mrow></mrow></semantics></math></inline-formula>) nanopores. Results show that the <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mrow><mo stretchy="false">(</mo><mn>10</mn><mover><mn>1</mn><mo>¯</mo></mover><mn>0</mn><mo stretchy="false">)</mo><mtext>-</mtext><mi>β</mi></mrow></mrow></semantics></math></inline-formula> surface exhibits stronger water molecule structuring with a structure arranged in two layers and higher first-layer adsorption density (2.44 g/cm<sup>3</sup>) compared to the (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mrow><mo stretchy="false">(</mo><mn>10</mn><mover><mn>1</mn><mo>¯</mo></mover><mn>0</mn><mo stretchy="false">)</mo><mtext>-</mtext><mi>α</mi></mrow></mrow></semantics></math></inline-formula> surface (1.68 g/cm³). The flow flux under the <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mrow><mo stretchy="false">(</mo><mn>10</mn><mover><mn>1</mn><mo>¯</mo></mover><mn>0</mn><mo stretchy="false">)</mo><mtext>-</mtext><mi>α</mi></mrow></mrow></semantics></math></inline-formula> surface is approximately 1.2 times higher than that under the <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mrow><mo stretchy="false">(</mo><mn>10</mn><mover><mn>1</mn><mo>¯</mo></mover><mn>0</mn><mo stretchy="false">)</mo><mtext>-</mtext><mi>β</mi></mrow></mrow></semantics></math></inline-formula> surface across various pressure gradients. We developed a theoretical model dividing the pore space into non-flowing, adsorbed, and bulk water regions, with critical thicknesses of 0.14 nm and 0.27 nm for the non-flowing region, and 0.15 nm for the adsorbed region in both surfaces. This model effectively predicts velocity distributions and volumetric flow rates with errors generally below 5%. Our findings provide insights into water transport mechanisms in shale inorganic nanopores and offer practical guidance for numerical simulation of shale gas production through dewatering operations.
ISSN:2079-4991