Investigations of CO2-water wettability of coal

NMR relaxation method

Xiaoxiao Sun, Yanbin Yaoa, Dameng Liu, Yingfang Zhou

Research output: Contribution to journalArticle

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3 Downloads (Pure)

Abstract

Carbon geo-sequestration (CGS) and recovery enhancement with carbon dioxide injection (CO2- ECBM) have brought increasing focus on the CO2 and water wettability of coal. The CO2 and water contact angles measured using existing conventional methods, such as the pendent drop tilting plate technique and the captive-bubble technique, show low reproducibility due to coal heterogeneity and operational complexity. In this study, a novel NMR-based approach was developed to evaluate the CO2 and water wettability of coal. The experimental results of nine bituminous and anthracite coals show that water wettability can be linearly correlated with the changes of the T2 spectra peak positions. Based on the measured contact angle from the profile of the water adhering to the coal powder disc and the T2 from the NMR of coal powder, we proposed a linear formulation to evaluate the contact angle using the change of T2g of P3. Using this method, we analyzed the CO2-water wettability characteristics of coal. The results show that CO2 reduces the water wettability of coal. Low temperature and/or high CO2 pressure can enhance the CO2 wettability of coal. The change of water-coal wetting behavior with injection of CO2, is resulted by three factors: change of CO2 adsorption capacity of coal, change of interfacial tension, and dissolution of CO2 in water. This study makes it possible to evaluate changes in the water and CO2 wettability of coal, which is essential for evaluating the fluid-interaction mechanisms during the process of carbon geo-sequestration and enhanced coalbed methane recovery with carbon dioxideinjection.
Original languageEnglish
Pages (from-to)38-50
Number of pages13
JournalInternational Journal Of Coal Geology
Volume188
Early online date8 Feb 2018
DOIs
Publication statusPublished - 1 Mar 2018

Fingerprint

wettability
nuclear magnetic resonance
Wetting
Nuclear magnetic resonance
Coal
coal
Water
water
Contact angle
Carbon
method
carbon
Powders
Recovery
anthracite
coalbed methane
Anthracite
Bubbles (in fluids)
wetting
Surface tension

Keywords

  • CO2 sequestration
  • coalbed methane
  • coal
  • wettability
  • relative permeability

Cite this

Investigations of CO2-water wettability of coal : NMR relaxation method. / Sun, Xiaoxiao; Yaoa, Yanbin; Liu, Dameng; Zhou, Yingfang.

In: International Journal Of Coal Geology, Vol. 188, 01.03.2018, p. 38-50.

Research output: Contribution to journalArticle

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abstract = "Carbon geo-sequestration (CGS) and recovery enhancement with carbon dioxide injection (CO2- ECBM) have brought increasing focus on the CO2 and water wettability of coal. The CO2 and water contact angles measured using existing conventional methods, such as the pendent drop tilting plate technique and the captive-bubble technique, show low reproducibility due to coal heterogeneity and operational complexity. In this study, a novel NMR-based approach was developed to evaluate the CO2 and water wettability of coal. The experimental results of nine bituminous and anthracite coals show that water wettability can be linearly correlated with the changes of the T2 spectra peak positions. Based on the measured contact angle from the profile of the water adhering to the coal powder disc and the T2 from the NMR of coal powder, we proposed a linear formulation to evaluate the contact angle using the change of T2g of P3. Using this method, we analyzed the CO2-water wettability characteristics of coal. The results show that CO2 reduces the water wettability of coal. Low temperature and/or high CO2 pressure can enhance the CO2 wettability of coal. The change of water-coal wetting behavior with injection of CO2, is resulted by three factors: change of CO2 adsorption capacity of coal, change of interfacial tension, and dissolution of CO2 in water. This study makes it possible to evaluate changes in the water and CO2 wettability of coal, which is essential for evaluating the fluid-interaction mechanisms during the process of carbon geo-sequestration and enhanced coalbed methane recovery with carbon dioxideinjection.",
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note = "Acknowledgments We acknowledge financial support from the National Natural Science Foundation of China (41472137), the Key Research and Development Projects of The Xinjiang Uygur Autonomous Region (2017B03019-01), and the National Major Research Program for Science and Technology of China (2016ZX05043-001), and the Royal Society Edinburgh and National Natural Science Foundation China (NSFC 41711530129).",
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AU - Sun, Xiaoxiao

AU - Yaoa, Yanbin

AU - Liu, Dameng

AU - Zhou, Yingfang

N1 - Acknowledgments We acknowledge financial support from the National Natural Science Foundation of China (41472137), the Key Research and Development Projects of The Xinjiang Uygur Autonomous Region (2017B03019-01), and the National Major Research Program for Science and Technology of China (2016ZX05043-001), and the Royal Society Edinburgh and National Natural Science Foundation China (NSFC 41711530129).

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N2 - Carbon geo-sequestration (CGS) and recovery enhancement with carbon dioxide injection (CO2- ECBM) have brought increasing focus on the CO2 and water wettability of coal. The CO2 and water contact angles measured using existing conventional methods, such as the pendent drop tilting plate technique and the captive-bubble technique, show low reproducibility due to coal heterogeneity and operational complexity. In this study, a novel NMR-based approach was developed to evaluate the CO2 and water wettability of coal. The experimental results of nine bituminous and anthracite coals show that water wettability can be linearly correlated with the changes of the T2 spectra peak positions. Based on the measured contact angle from the profile of the water adhering to the coal powder disc and the T2 from the NMR of coal powder, we proposed a linear formulation to evaluate the contact angle using the change of T2g of P3. Using this method, we analyzed the CO2-water wettability characteristics of coal. The results show that CO2 reduces the water wettability of coal. Low temperature and/or high CO2 pressure can enhance the CO2 wettability of coal. The change of water-coal wetting behavior with injection of CO2, is resulted by three factors: change of CO2 adsorption capacity of coal, change of interfacial tension, and dissolution of CO2 in water. This study makes it possible to evaluate changes in the water and CO2 wettability of coal, which is essential for evaluating the fluid-interaction mechanisms during the process of carbon geo-sequestration and enhanced coalbed methane recovery with carbon dioxideinjection.

AB - Carbon geo-sequestration (CGS) and recovery enhancement with carbon dioxide injection (CO2- ECBM) have brought increasing focus on the CO2 and water wettability of coal. The CO2 and water contact angles measured using existing conventional methods, such as the pendent drop tilting plate technique and the captive-bubble technique, show low reproducibility due to coal heterogeneity and operational complexity. In this study, a novel NMR-based approach was developed to evaluate the CO2 and water wettability of coal. The experimental results of nine bituminous and anthracite coals show that water wettability can be linearly correlated with the changes of the T2 spectra peak positions. Based on the measured contact angle from the profile of the water adhering to the coal powder disc and the T2 from the NMR of coal powder, we proposed a linear formulation to evaluate the contact angle using the change of T2g of P3. Using this method, we analyzed the CO2-water wettability characteristics of coal. The results show that CO2 reduces the water wettability of coal. Low temperature and/or high CO2 pressure can enhance the CO2 wettability of coal. The change of water-coal wetting behavior with injection of CO2, is resulted by three factors: change of CO2 adsorption capacity of coal, change of interfacial tension, and dissolution of CO2 in water. This study makes it possible to evaluate changes in the water and CO2 wettability of coal, which is essential for evaluating the fluid-interaction mechanisms during the process of carbon geo-sequestration and enhanced coalbed methane recovery with carbon dioxideinjection.

KW - CO2 sequestration

KW - coalbed methane

KW - coal

KW - wettability

KW - relative permeability

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JO - International Journal Of Coal Geology

JF - International Journal Of Coal Geology

SN - 0166-5162

ER -