Synchrotron X-ray tomographic characterization of microstructural evolution in coal due to supercritical CO2 injection at in-situ conditions

Guanglei Zhang, P. G. Ranjith, Bisheng Wu, M. S.A. Perera, Asadul Haque, Dongyin Li

Research output: Contribution to journalArticleResearchpeer-review

Abstract

Microstructural evolution in coal due to CO2 injection directly influences the gas transport and storage properties of coal during CO2 sequestration in deep coal seams. Using synchrotron X-ray tomography, we performed CT imaging under simulated reservoir conditions with a novel X-ray transparent core holder and investigated the time-dependent evolution of 3-D microstructures of an anthracite coal with 1.37% moisture as-received interacted with supercritical CO2 (ScCO2). Three sets of CT scans were taken: (1) coal was subjected to 10 MPa confining pressure before exposed to ScCO2, (2) coal was subjected to 10 MPa confining pressure and after 7 h of exposure to ScCO2, and (3) coal was subjected to 10 MPa confining pressure and after 53 h of exposure to ScCO2. When ScCO2 interacts with coal, complex physico-chemical reactions occur, changing coal microstructures in multiple ways and resulting in significant permeability changes. After 7 h ScCO2 injection, we directly observed the pre-existing microfracture closure, which was attributed to coal swelling. A significant permeability reduction was measured from 3.0 to 0.24 µD with up to 26 h CO2 injection. With increasing injection duration, interestingly, we observed the wormhole growth in coal due to hydrocarbon mobilization and mineral dissolution, which accordingly caused a permeability rebound to 1.2 µD after 53 h CO2 injection. Coal swelling occurred readily upon ScCO2 injection but hydrocarbon mobilization and mineral dissolution were delayed to affect the permeability probably due to the slower reaction kinetics. This study suggests that ScCO2 injection has the potential to improve the permeability and enhance the coalbed methane recovery due to the effects of hydrocarbon mobilization and mineral dissolution.

Original languageEnglish
Article number115696
Number of pages8
JournalFuel
Volume255
DOIs
Publication statusPublished - 1 Nov 2019

Keywords

  • CO sequestration
  • Coal swelling
  • Hydrocarbon mobilization
  • Mineral dissolution
  • Synchrotron
  • X-ray CT

Cite this

@article{b2fa2886d7304f7dbcdc435a874b9f3a,
title = "Synchrotron X-ray tomographic characterization of microstructural evolution in coal due to supercritical CO2 injection at in-situ conditions",
abstract = "Microstructural evolution in coal due to CO2 injection directly influences the gas transport and storage properties of coal during CO2 sequestration in deep coal seams. Using synchrotron X-ray tomography, we performed CT imaging under simulated reservoir conditions with a novel X-ray transparent core holder and investigated the time-dependent evolution of 3-D microstructures of an anthracite coal with 1.37{\%} moisture as-received interacted with supercritical CO2 (ScCO2). Three sets of CT scans were taken: (1) coal was subjected to 10 MPa confining pressure before exposed to ScCO2, (2) coal was subjected to 10 MPa confining pressure and after 7 h of exposure to ScCO2, and (3) coal was subjected to 10 MPa confining pressure and after 53 h of exposure to ScCO2. When ScCO2 interacts with coal, complex physico-chemical reactions occur, changing coal microstructures in multiple ways and resulting in significant permeability changes. After 7 h ScCO2 injection, we directly observed the pre-existing microfracture closure, which was attributed to coal swelling. A significant permeability reduction was measured from 3.0 to 0.24 µD with up to 26 h CO2 injection. With increasing injection duration, interestingly, we observed the wormhole growth in coal due to hydrocarbon mobilization and mineral dissolution, which accordingly caused a permeability rebound to 1.2 µD after 53 h CO2 injection. Coal swelling occurred readily upon ScCO2 injection but hydrocarbon mobilization and mineral dissolution were delayed to affect the permeability probably due to the slower reaction kinetics. This study suggests that ScCO2 injection has the potential to improve the permeability and enhance the coalbed methane recovery due to the effects of hydrocarbon mobilization and mineral dissolution.",
keywords = "CO sequestration, Coal swelling, Hydrocarbon mobilization, Mineral dissolution, Synchrotron, X-ray CT",
author = "Guanglei Zhang and Ranjith, {P. G.} and Bisheng Wu and Perera, {M. S.A.} and Asadul Haque and Dongyin Li",
year = "2019",
month = "11",
day = "1",
doi = "10.1016/j.fuel.2019.115696",
language = "English",
volume = "255",
journal = "Fuel",
issn = "0016-2361",
publisher = "Elsevier",

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Synchrotron X-ray tomographic characterization of microstructural evolution in coal due to supercritical CO2 injection at in-situ conditions. / Zhang, Guanglei; Ranjith, P. G.; Wu, Bisheng; Perera, M. S.A.; Haque, Asadul; Li, Dongyin.

In: Fuel, Vol. 255, 115696, 01.11.2019.

Research output: Contribution to journalArticleResearchpeer-review

TY - JOUR

T1 - Synchrotron X-ray tomographic characterization of microstructural evolution in coal due to supercritical CO2 injection at in-situ conditions

AU - Zhang, Guanglei

AU - Ranjith, P. G.

AU - Wu, Bisheng

AU - Perera, M. S.A.

AU - Haque, Asadul

AU - Li, Dongyin

PY - 2019/11/1

Y1 - 2019/11/1

N2 - Microstructural evolution in coal due to CO2 injection directly influences the gas transport and storage properties of coal during CO2 sequestration in deep coal seams. Using synchrotron X-ray tomography, we performed CT imaging under simulated reservoir conditions with a novel X-ray transparent core holder and investigated the time-dependent evolution of 3-D microstructures of an anthracite coal with 1.37% moisture as-received interacted with supercritical CO2 (ScCO2). Three sets of CT scans were taken: (1) coal was subjected to 10 MPa confining pressure before exposed to ScCO2, (2) coal was subjected to 10 MPa confining pressure and after 7 h of exposure to ScCO2, and (3) coal was subjected to 10 MPa confining pressure and after 53 h of exposure to ScCO2. When ScCO2 interacts with coal, complex physico-chemical reactions occur, changing coal microstructures in multiple ways and resulting in significant permeability changes. After 7 h ScCO2 injection, we directly observed the pre-existing microfracture closure, which was attributed to coal swelling. A significant permeability reduction was measured from 3.0 to 0.24 µD with up to 26 h CO2 injection. With increasing injection duration, interestingly, we observed the wormhole growth in coal due to hydrocarbon mobilization and mineral dissolution, which accordingly caused a permeability rebound to 1.2 µD after 53 h CO2 injection. Coal swelling occurred readily upon ScCO2 injection but hydrocarbon mobilization and mineral dissolution were delayed to affect the permeability probably due to the slower reaction kinetics. This study suggests that ScCO2 injection has the potential to improve the permeability and enhance the coalbed methane recovery due to the effects of hydrocarbon mobilization and mineral dissolution.

AB - Microstructural evolution in coal due to CO2 injection directly influences the gas transport and storage properties of coal during CO2 sequestration in deep coal seams. Using synchrotron X-ray tomography, we performed CT imaging under simulated reservoir conditions with a novel X-ray transparent core holder and investigated the time-dependent evolution of 3-D microstructures of an anthracite coal with 1.37% moisture as-received interacted with supercritical CO2 (ScCO2). Three sets of CT scans were taken: (1) coal was subjected to 10 MPa confining pressure before exposed to ScCO2, (2) coal was subjected to 10 MPa confining pressure and after 7 h of exposure to ScCO2, and (3) coal was subjected to 10 MPa confining pressure and after 53 h of exposure to ScCO2. When ScCO2 interacts with coal, complex physico-chemical reactions occur, changing coal microstructures in multiple ways and resulting in significant permeability changes. After 7 h ScCO2 injection, we directly observed the pre-existing microfracture closure, which was attributed to coal swelling. A significant permeability reduction was measured from 3.0 to 0.24 µD with up to 26 h CO2 injection. With increasing injection duration, interestingly, we observed the wormhole growth in coal due to hydrocarbon mobilization and mineral dissolution, which accordingly caused a permeability rebound to 1.2 µD after 53 h CO2 injection. Coal swelling occurred readily upon ScCO2 injection but hydrocarbon mobilization and mineral dissolution were delayed to affect the permeability probably due to the slower reaction kinetics. This study suggests that ScCO2 injection has the potential to improve the permeability and enhance the coalbed methane recovery due to the effects of hydrocarbon mobilization and mineral dissolution.

KW - CO sequestration

KW - Coal swelling

KW - Hydrocarbon mobilization

KW - Mineral dissolution

KW - Synchrotron

KW - X-ray CT

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U2 - 10.1016/j.fuel.2019.115696

DO - 10.1016/j.fuel.2019.115696

M3 - Article

VL - 255

JO - Fuel

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