Pore-scale determination of residual gas remobilization and critical saturation in geological CO2 storage: a pore-network modeling approach
File(s)Water Resources Research - 2023 - Moghadasi.pdf (2.6 MB)
Published version
Author(s)
Type
Journal Article
Abstract
Remobilization of residually trapped CO2 can occur under pressure depletion, caused by any sort of leakage, brine extraction for pressure maintenance purposes, or simply by near wellbore pressure dissipation once CO2 injection has ceased. This phenomenon affects the long-term stability of CO2 residual trapping and should therefore be considered for an accurate assessment of CO2 storage security. In this study, pore-network modeling is performed to understand the relevant physics of remobilization. Gas remobilization occurs at a higher gas saturation than the residual saturation, the so-called critical saturation; the difference is called the mobilization saturation, a parameter that is a function of the network properties and the mechanisms involved. Regardless of the network type and properties, Ostwald ripening tends to slightly increase the mobilization saturation, thereby enhancing the security of residual trapping. Moreover, significant hysteresis and reduction in gas relative permeability is observed, implying slow reconnection of the trapped gas clusters. These observations are safety enhancing features, due to which the remobilization of residual CO2 is delayed. The results, consistent with our previous analysis of the field-scale Heletz experiments, have important implications for underground gas and CO2 storage. In the context of CO2 storage, they provide important insights into the fate of residual trapping in both the short and long term.
Date Issued
2023-06
Date Acceptance
2023-05-23
Citation
Water Resources Research, 2023, 59 (6), pp.1-16
ISSN
0043-1397
Publisher
Wiley
Start Page
1
End Page
16
Journal / Book Title
Water Resources Research
Volume
59
Issue
6
Copyright Statement
© 2023. The Authors.
This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
License URL
Identifier
https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2022WR033686
Publication Status
Published
Article Number
e2022WR033686
Date Publish Online
2023-06-20