Novel chemical stimulation for geothermal reservoirs by chelating agent driven selective mineral dissolution in fractured rocks

Abstract Improving geothermal systems through hydraulic stimulation to create highly permeable fractured rocks can induce seismicity. Therefore, the technique must be applied at a moderate intensity; this has led to concerns of insufficient permeability enhancement. Adding chemical stimulation can m...

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Autores principales: Noriaki Watanabe, Kaori Takahashi, Ryota Takahashi, Kengo Nakamura, Yusuke Kumano, Kohei Akaku, Tetsuya Tamagawa, Takeshi Komai
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Publicado: Nature Portfolio 2021
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Acceso en línea:https://doaj.org/article/22fea75140814b748c47c6ed322b6a49
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spelling oai:doaj.org-article:22fea75140814b748c47c6ed322b6a492021-12-02T19:16:14ZNovel chemical stimulation for geothermal reservoirs by chelating agent driven selective mineral dissolution in fractured rocks10.1038/s41598-021-99511-62045-2322https://doaj.org/article/22fea75140814b748c47c6ed322b6a492021-10-01T00:00:00Zhttps://doi.org/10.1038/s41598-021-99511-6https://doaj.org/toc/2045-2322Abstract Improving geothermal systems through hydraulic stimulation to create highly permeable fractured rocks can induce seismicity. Therefore, the technique must be applied at a moderate intensity; this has led to concerns of insufficient permeability enhancement. Adding chemical stimulation can mitigate these issues, but traditional methods using strong mineral acids have challenges in terms of achieving mineral dissolution over long distances and highly variable fluid chemistry. Here, we demonstrate a novel chemical stimulation method for improving the permeability of rock fractures using a chelating agent that substantially enhances the dissolution rate of specific minerals to create voids that are sustained under crustal stress without the challenges associated with the traditional methods. Applying this agent to fractured granite samples under confining stress at 200 °C in conjunction with 20 wt% aqueous solutions of sodium salts of environmentally friendly chelating agents (N-(2-hydroxyethyl)ethylenediamine-N, N′, N′-triacetic acid and N, N-bis(carboxymethyl)-l-glutamic acid) at pH 4 was assessed. A significant permeability enhancement of up to approximately sixfold was observed within 2 h, primarily due to the formation of voids based on the selective dissolution of biotite. These results demonstrate a new approach for chemical stimulation.Noriaki WatanabeKaori TakahashiRyota TakahashiKengo NakamuraYusuke KumanoKohei AkakuTetsuya TamagawaTakeshi KomaiNature PortfolioarticleMedicineRScienceQENScientific Reports, Vol 11, Iss 1, Pp 1-11 (2021)
institution DOAJ
collection DOAJ
language EN
topic Medicine
R
Science
Q
spellingShingle Medicine
R
Science
Q
Noriaki Watanabe
Kaori Takahashi
Ryota Takahashi
Kengo Nakamura
Yusuke Kumano
Kohei Akaku
Tetsuya Tamagawa
Takeshi Komai
Novel chemical stimulation for geothermal reservoirs by chelating agent driven selective mineral dissolution in fractured rocks
description Abstract Improving geothermal systems through hydraulic stimulation to create highly permeable fractured rocks can induce seismicity. Therefore, the technique must be applied at a moderate intensity; this has led to concerns of insufficient permeability enhancement. Adding chemical stimulation can mitigate these issues, but traditional methods using strong mineral acids have challenges in terms of achieving mineral dissolution over long distances and highly variable fluid chemistry. Here, we demonstrate a novel chemical stimulation method for improving the permeability of rock fractures using a chelating agent that substantially enhances the dissolution rate of specific minerals to create voids that are sustained under crustal stress without the challenges associated with the traditional methods. Applying this agent to fractured granite samples under confining stress at 200 °C in conjunction with 20 wt% aqueous solutions of sodium salts of environmentally friendly chelating agents (N-(2-hydroxyethyl)ethylenediamine-N, N′, N′-triacetic acid and N, N-bis(carboxymethyl)-l-glutamic acid) at pH 4 was assessed. A significant permeability enhancement of up to approximately sixfold was observed within 2 h, primarily due to the formation of voids based on the selective dissolution of biotite. These results demonstrate a new approach for chemical stimulation.
format article
author Noriaki Watanabe
Kaori Takahashi
Ryota Takahashi
Kengo Nakamura
Yusuke Kumano
Kohei Akaku
Tetsuya Tamagawa
Takeshi Komai
author_facet Noriaki Watanabe
Kaori Takahashi
Ryota Takahashi
Kengo Nakamura
Yusuke Kumano
Kohei Akaku
Tetsuya Tamagawa
Takeshi Komai
author_sort Noriaki Watanabe
title Novel chemical stimulation for geothermal reservoirs by chelating agent driven selective mineral dissolution in fractured rocks
title_short Novel chemical stimulation for geothermal reservoirs by chelating agent driven selective mineral dissolution in fractured rocks
title_full Novel chemical stimulation for geothermal reservoirs by chelating agent driven selective mineral dissolution in fractured rocks
title_fullStr Novel chemical stimulation for geothermal reservoirs by chelating agent driven selective mineral dissolution in fractured rocks
title_full_unstemmed Novel chemical stimulation for geothermal reservoirs by chelating agent driven selective mineral dissolution in fractured rocks
title_sort novel chemical stimulation for geothermal reservoirs by chelating agent driven selective mineral dissolution in fractured rocks
publisher Nature Portfolio
publishDate 2021
url https://doaj.org/article/22fea75140814b748c47c6ed322b6a49
work_keys_str_mv AT noriakiwatanabe novelchemicalstimulationforgeothermalreservoirsbychelatingagentdrivenselectivemineraldissolutioninfracturedrocks
AT kaoritakahashi novelchemicalstimulationforgeothermalreservoirsbychelatingagentdrivenselectivemineraldissolutioninfracturedrocks
AT ryotatakahashi novelchemicalstimulationforgeothermalreservoirsbychelatingagentdrivenselectivemineraldissolutioninfracturedrocks
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AT tetsuyatamagawa novelchemicalstimulationforgeothermalreservoirsbychelatingagentdrivenselectivemineraldissolutioninfracturedrocks
AT takeshikomai novelchemicalstimulationforgeothermalreservoirsbychelatingagentdrivenselectivemineraldissolutioninfracturedrocks
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