Transient increase in reactive surface and the macroscopic Damköhler number in chalk dissolution

Y. Yang*, M. Rogowska, Y. Zheng, Stefan Bruns, C. Gundlach, S.L.S. Stipp, H. O. Sørensen

*Corresponding author for this work

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Abstract

Surface area is an important input parameter for reactive transport modelling and it changes with time when rocks dissolve. Here we show direct observations of increased surface area due to chalk (predominantly CaCO3) dissolution, using 3D in situ X-ray microtomography. This transient increase cannot be explained by changes in fluid accessibility or by surface roughening that arises from preferential leaching. We use model simulations to explain how this increase in surface area correlates with the size of the Damköhler space, defined macroscopically using a phenomenological dissolution rate law and the cumulative surface of the microstructure. We attribute this transient increase to the coupling between fluid flow and mineral dissolution and argue that the extent is determined by the advective penetration distance of the reactants. We conclude that using a macroscopic dimensionless number as a qualitative indicator for microstructure evolution has limited applicability.
Original languageEnglish
JournalJournal of Hydrology
Volume571
Pages (from-to)21-35
Number of pages15
ISSN0022-1694
DOIs
Publication statusPublished - 2019

Keywords

  • X-ray tomography
  • In situ imaging
  • Chalk Dissolution
  • Microstructure evolution
  • Reactive surface area
  • Damköhler number

Cite this

Yang, Y. ; Rogowska, M. ; Zheng, Y. ; Bruns, Stefan ; Gundlach, C. ; Stipp, S.L.S. ; Sørensen, H. O. / Transient increase in reactive surface and the macroscopic Damköhler number in chalk dissolution. In: Journal of Hydrology. 2019 ; Vol. 571. pp. 21-35.
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abstract = "Surface area is an important input parameter for reactive transport modelling and it changes with time when rocks dissolve. Here we show direct observations of increased surface area due to chalk (predominantly CaCO3) dissolution, using 3D in situ X-ray microtomography. This transient increase cannot be explained by changes in fluid accessibility or by surface roughening that arises from preferential leaching. We use model simulations to explain how this increase in surface area correlates with the size of the Damk{\"o}hler space, defined macroscopically using a phenomenological dissolution rate law and the cumulative surface of the microstructure. We attribute this transient increase to the coupling between fluid flow and mineral dissolution and argue that the extent is determined by the advective penetration distance of the reactants. We conclude that using a macroscopic dimensionless number as a qualitative indicator for microstructure evolution has limited applicability.",
keywords = "X-ray tomography, In situ imaging, Chalk Dissolution, Microstructure evolution, Reactive surface area, Damk{\"o}hler number",
author = "Y. Yang and M. Rogowska and Y. Zheng and Stefan Bruns and C. Gundlach and S.L.S. Stipp and S{\o}rensen, {H. O.}",
year = "2019",
doi = "10.1016/j.jhydrol.2019.01.032",
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pages = "21--35",
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Transient increase in reactive surface and the macroscopic Damköhler number in chalk dissolution. / Yang, Y.; Rogowska, M.; Zheng, Y.; Bruns, Stefan; Gundlach, C.; Stipp, S.L.S.; Sørensen, H. O.

In: Journal of Hydrology, Vol. 571, 2019, p. 21-35.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - Transient increase in reactive surface and the macroscopic Damköhler number in chalk dissolution

AU - Yang, Y.

AU - Rogowska, M.

AU - Zheng, Y.

AU - Bruns, Stefan

AU - Gundlach, C.

AU - Stipp, S.L.S.

AU - Sørensen, H. O.

PY - 2019

Y1 - 2019

N2 - Surface area is an important input parameter for reactive transport modelling and it changes with time when rocks dissolve. Here we show direct observations of increased surface area due to chalk (predominantly CaCO3) dissolution, using 3D in situ X-ray microtomography. This transient increase cannot be explained by changes in fluid accessibility or by surface roughening that arises from preferential leaching. We use model simulations to explain how this increase in surface area correlates with the size of the Damköhler space, defined macroscopically using a phenomenological dissolution rate law and the cumulative surface of the microstructure. We attribute this transient increase to the coupling between fluid flow and mineral dissolution and argue that the extent is determined by the advective penetration distance of the reactants. We conclude that using a macroscopic dimensionless number as a qualitative indicator for microstructure evolution has limited applicability.

AB - Surface area is an important input parameter for reactive transport modelling and it changes with time when rocks dissolve. Here we show direct observations of increased surface area due to chalk (predominantly CaCO3) dissolution, using 3D in situ X-ray microtomography. This transient increase cannot be explained by changes in fluid accessibility or by surface roughening that arises from preferential leaching. We use model simulations to explain how this increase in surface area correlates with the size of the Damköhler space, defined macroscopically using a phenomenological dissolution rate law and the cumulative surface of the microstructure. We attribute this transient increase to the coupling between fluid flow and mineral dissolution and argue that the extent is determined by the advective penetration distance of the reactants. We conclude that using a macroscopic dimensionless number as a qualitative indicator for microstructure evolution has limited applicability.

KW - X-ray tomography

KW - In situ imaging

KW - Chalk Dissolution

KW - Microstructure evolution

KW - Reactive surface area

KW - Damköhler number

U2 - 10.1016/j.jhydrol.2019.01.032

DO - 10.1016/j.jhydrol.2019.01.032

M3 - Journal article

VL - 571

SP - 21

EP - 35

JO - Journal of Hydrology

JF - Journal of Hydrology

SN - 0022-1694

ER -