Multiscale investigation of CO2 hydrate self-sealing potential for carbon geo-sequestration

Jarand Gauteplass, Stian Almenningen, Geir Ersland, Tanja Barth, Jinhai Yang, Antonin Chapoy

Research output: Contribution to journalArticle

2 Citations (Scopus)
52 Downloads (Pure)

Abstract

Storage of liquid CO 2 in shallow geological formations is a recently proposed concept that can facilitate increased storage capacity and improved mobility control. If stored below the gas hydrate stability zone (GHSZ), unwanted vertical migration of CO 2 can be effectively inhibited by the formation of solid hydrate layers. Lowering the risks of CO 2 leakage to the atmosphere is instrumental to accelerate the implementation of full-scale carbon sequestration in the North Sea and elsewhere. In the laboratory, we have successfully visualized CO 2 trapping phenomena, measured CO 2 leakage rates, and demonstrated that the integrity of the hydrate seal strongly depends on fluid-rock interactions and initial water distribution. CO 2 propagation in water-filled core samples has been monitored over a total of 140 days inside the GHSZ. Solid CO 2 hydrate formed and sealed the pore space in both homogeneous sandstone and heterogeneous limestone cores. However, the physical flow barrier developed considerably faster in sandstone (after 1.8 pore volumes – PV) compared to limestone (after 7.4 PV), with a factor ten reduced CO 2 leakage rate through the seal in favor of sandstone. Furthermore, pore-scale images of upward CO 2 migration verified trapping of CO 2 both as solid hydrate precipitation and as liquid CO 2 clusters made discontinuous and stabilized by capillary forces. Small-scale hydrate rearrangement followed initial formation, and caused temporarily dissociation of local hydrate structures without affecting the overall integrity of the seal. Our study suggests that a homogeneous, water-filled GHSZ directly above a CO 2 storage site can provide a secondary safety mechanism and significantly reduce the risk of CO 2 leakage.

Original languageEnglish
Article number122646
JournalChemical Engineering Journal
Volume381
Early online date28 Aug 2019
DOIs
Publication statusPublished - 1 Feb 2020

Keywords

  • CO storage
  • Hydrate seal
  • Leakage rate
  • Pore-level visualization
  • Secondary safety factor

ASJC Scopus subject areas

  • Chemistry(all)
  • Environmental Chemistry
  • Chemical Engineering(all)
  • Industrial and Manufacturing Engineering

Fingerprint Dive into the research topics of 'Multiscale investigation of CO<sub>2</sub> hydrate self-sealing potential for carbon geo-sequestration'. Together they form a unique fingerprint.

Cite this