Evaluation of Coal Pore Connectivity Using N2 Sorption Isotherm and Spontaneous Imbibition Tests

Pore structure and connectivity of coal are critical factors in coal gas migration and production, which can be characterized by studying the kinetics of capillary imbibition behaviour within the pore spaces. In order to investigate them, six typical coal samples from different collieries in China (...

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Main Authors: Tong-qiang Xia, Jiao-fei He, Shi-xing Fan, Qiang-qiang Zhang, Zi-long Li, Dun-shuai Sun
Format: Article
Language:English
Published: Hindawi-Wiley 2021-01-01
Series:Geofluids
Online Access:http://dx.doi.org/10.1155/2021/8848932
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spelling doaj-3e032571843c4b4b9df4985f3b99cab82021-08-30T00:01:15ZengHindawi-WileyGeofluids1468-81232021-01-01202110.1155/2021/8848932Evaluation of Coal Pore Connectivity Using N2 Sorption Isotherm and Spontaneous Imbibition TestsTong-qiang Xia0Jiao-fei He1Shi-xing Fan2Qiang-qiang Zhang3Zi-long Li4Dun-shuai Sun5Shaanxi Provincial Key Laboratory of Geological Support for Coal Green ExploitationSchool of Electrical and Power EngineeringState Key Laboratory of Coal Resources in Western ChinaSchool of Electrical and Power EngineeringState Key Laboratory of Coal Resources in Western ChinaSchool of Electrical and Power EngineeringPore structure and connectivity of coal are critical factors in coal gas migration and production, which can be characterized by studying the kinetics of capillary imbibition behaviour within the pore spaces. In order to investigate them, six typical coal samples from different collieries in China (Yangcun, Changcun, Gengcun, Yanbei, Dongxia, and Yuwu coal) are selected to carry out N2 sorption isotherm and spontaneous imbibition tests. Results from N2 sorption isotherm tests show that there is a great difference between the total specific surface area and total pore volume among the six coal samples. Their total specific surface area varies from 0.302 to 3.275 m2/g, and the total pore volume varies from 1.782 to 10.94 mm3/g. The pore volume relationship of coal sample among them is in order from the large to small: Dongxia>Yangcun>Gengcun>Yuwu>Changcun>Yanbei coal, and the specific surface area is in order from the large to small: Yangcun>Dongxia>Changcun>Yuwu>Gengcun>Yanbei coal. The imbibition characters of six coal samples were matched using explicit the short-time limit t⟶0 and long-time limit t⟶∞ models by Zhmud et al., respectively. The results show that the long-time limit t⟶∞ model is better. Combined with pore structure analysis, it can be qualitatively analyzed that the imbibition capacity of six coal samples is positively correlated with the connectivity of coal pores, which is ranked as Changcun>Yanbei>Gengcun>Yangcun>Dongxia>Yuwu coal. This work will help understand the mechanism controlling fluid loss and ultimate gas/oil recovery in unconventional hydrocarbon exploration.http://dx.doi.org/10.1155/2021/8848932
collection DOAJ
language English
format Article
sources DOAJ
author Tong-qiang Xia
Jiao-fei He
Shi-xing Fan
Qiang-qiang Zhang
Zi-long Li
Dun-shuai Sun
spellingShingle Tong-qiang Xia
Jiao-fei He
Shi-xing Fan
Qiang-qiang Zhang
Zi-long Li
Dun-shuai Sun
Evaluation of Coal Pore Connectivity Using N2 Sorption Isotherm and Spontaneous Imbibition Tests
Geofluids
author_facet Tong-qiang Xia
Jiao-fei He
Shi-xing Fan
Qiang-qiang Zhang
Zi-long Li
Dun-shuai Sun
author_sort Tong-qiang Xia
title Evaluation of Coal Pore Connectivity Using N2 Sorption Isotherm and Spontaneous Imbibition Tests
title_short Evaluation of Coal Pore Connectivity Using N2 Sorption Isotherm and Spontaneous Imbibition Tests
title_full Evaluation of Coal Pore Connectivity Using N2 Sorption Isotherm and Spontaneous Imbibition Tests
title_fullStr Evaluation of Coal Pore Connectivity Using N2 Sorption Isotherm and Spontaneous Imbibition Tests
title_full_unstemmed Evaluation of Coal Pore Connectivity Using N2 Sorption Isotherm and Spontaneous Imbibition Tests
title_sort evaluation of coal pore connectivity using n2 sorption isotherm and spontaneous imbibition tests
publisher Hindawi-Wiley
series Geofluids
issn 1468-8123
publishDate 2021-01-01
description Pore structure and connectivity of coal are critical factors in coal gas migration and production, which can be characterized by studying the kinetics of capillary imbibition behaviour within the pore spaces. In order to investigate them, six typical coal samples from different collieries in China (Yangcun, Changcun, Gengcun, Yanbei, Dongxia, and Yuwu coal) are selected to carry out N2 sorption isotherm and spontaneous imbibition tests. Results from N2 sorption isotherm tests show that there is a great difference between the total specific surface area and total pore volume among the six coal samples. Their total specific surface area varies from 0.302 to 3.275 m2/g, and the total pore volume varies from 1.782 to 10.94 mm3/g. The pore volume relationship of coal sample among them is in order from the large to small: Dongxia>Yangcun>Gengcun>Yuwu>Changcun>Yanbei coal, and the specific surface area is in order from the large to small: Yangcun>Dongxia>Changcun>Yuwu>Gengcun>Yanbei coal. The imbibition characters of six coal samples were matched using explicit the short-time limit t⟶0 and long-time limit t⟶∞ models by Zhmud et al., respectively. The results show that the long-time limit t⟶∞ model is better. Combined with pore structure analysis, it can be qualitatively analyzed that the imbibition capacity of six coal samples is positively correlated with the connectivity of coal pores, which is ranked as Changcun>Yanbei>Gengcun>Yangcun>Dongxia>Yuwu coal. This work will help understand the mechanism controlling fluid loss and ultimate gas/oil recovery in unconventional hydrocarbon exploration.
url http://dx.doi.org/10.1155/2021/8848932
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