Nanoscale rock mechanical property changes in heterogeneous coal after water adsorption

© 2018 Elsevier Ltd Rock mechanical properties are of key importance in coal mining exploration, coal bed methane production and CO 2 storage in deep unmineable coal seams; accurate data is required so that geohazards (e.g. layer collapse or methane/CO 2 leakage) can be avoided. In this context it i...

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Main Authors: Zhang, Y., Lebedev, Maxim, Al-Yaseri, A., Yu, H., Xu, X., Sarmadivaleh, Mohammad, Barifcani, Ahmed, Iglauer, Stefan
Format: Journal Article
Published: Elsevier Ltd 2018
Online Access:http://hdl.handle.net/20.500.11937/65799
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author Zhang, Y.
Lebedev, Maxim
Al-Yaseri, A.
Yu, H.
Xu, X.
Sarmadivaleh, Mohammad
Barifcani, Ahmed
Iglauer, Stefan
author_facet Zhang, Y.
Lebedev, Maxim
Al-Yaseri, A.
Yu, H.
Xu, X.
Sarmadivaleh, Mohammad
Barifcani, Ahmed
Iglauer, Stefan
author_sort Zhang, Y.
building Curtin Institutional Repository
collection Online Access
description © 2018 Elsevier Ltd Rock mechanical properties are of key importance in coal mining exploration, coal bed methane production and CO 2 storage in deep unmineable coal seams; accurate data is required so that geohazards (e.g. layer collapse or methane/CO 2 leakage) can be avoided. In this context it is well established that coal matrix swelling due to water adsorption significantly changes the coal microstructure. However, how water adsorption and the associated with microstructural changes affect the mechanical properties is only poorly understood, despite the fact that micro-scale mechanical properties determine the overall geo-mechanical response as failure initiates at the weakest point. Thus, we measured nanoscale rock mechanical properties via nanoindentation tests and compared the results with traditional acoustic methods on heterogeneous medium rank coal samples in both dry and brine saturated conditions. The microscale heterogeneity of the rock mechanical properties was mapped and compared with the morphology of the sample (measured by SEM and microCT). While the nanoindentation tests measured decreasing indentation moduli after water adsorption (-60% to -66%), the traditional acoustic tests measured an increase (+17%). We concluded that acoustic tests failed to capture the accurate rock mechanical properties changes for the heterogeneous coal during water adsorption. It is thus necessary to measure the coal rock mechanical properties at the microscale to obtain more accurate data and reduce the risk of geohazards.
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institution Curtin University Malaysia
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publishDate 2018
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spelling curtin-20.500.11937-657992018-02-19T08:06:30Z Nanoscale rock mechanical property changes in heterogeneous coal after water adsorption Zhang, Y. Lebedev, Maxim Al-Yaseri, A. Yu, H. Xu, X. Sarmadivaleh, Mohammad Barifcani, Ahmed Iglauer, Stefan © 2018 Elsevier Ltd Rock mechanical properties are of key importance in coal mining exploration, coal bed methane production and CO 2 storage in deep unmineable coal seams; accurate data is required so that geohazards (e.g. layer collapse or methane/CO 2 leakage) can be avoided. In this context it is well established that coal matrix swelling due to water adsorption significantly changes the coal microstructure. However, how water adsorption and the associated with microstructural changes affect the mechanical properties is only poorly understood, despite the fact that micro-scale mechanical properties determine the overall geo-mechanical response as failure initiates at the weakest point. Thus, we measured nanoscale rock mechanical properties via nanoindentation tests and compared the results with traditional acoustic methods on heterogeneous medium rank coal samples in both dry and brine saturated conditions. The microscale heterogeneity of the rock mechanical properties was mapped and compared with the morphology of the sample (measured by SEM and microCT). While the nanoindentation tests measured decreasing indentation moduli after water adsorption (-60% to -66%), the traditional acoustic tests measured an increase (+17%). We concluded that acoustic tests failed to capture the accurate rock mechanical properties changes for the heterogeneous coal during water adsorption. It is thus necessary to measure the coal rock mechanical properties at the microscale to obtain more accurate data and reduce the risk of geohazards. 2018 Journal Article http://hdl.handle.net/20.500.11937/65799 10.1016/j.fuel.2018.01.006 Elsevier Ltd restricted
spellingShingle Zhang, Y.
Lebedev, Maxim
Al-Yaseri, A.
Yu, H.
Xu, X.
Sarmadivaleh, Mohammad
Barifcani, Ahmed
Iglauer, Stefan
Nanoscale rock mechanical property changes in heterogeneous coal after water adsorption
title Nanoscale rock mechanical property changes in heterogeneous coal after water adsorption
title_full Nanoscale rock mechanical property changes in heterogeneous coal after water adsorption
title_fullStr Nanoscale rock mechanical property changes in heterogeneous coal after water adsorption
title_full_unstemmed Nanoscale rock mechanical property changes in heterogeneous coal after water adsorption
title_short Nanoscale rock mechanical property changes in heterogeneous coal after water adsorption
title_sort nanoscale rock mechanical property changes in heterogeneous coal after water adsorption
url http://hdl.handle.net/20.500.11937/65799