Geophysical early warning of salt precipitation during geological carbon sequestration

Falcon Suarez, Ismael Himar ORCID: https://orcid.org/0000-0001-8576-5165; Livo, Kurt; Callow, Ben; Marin-Moreno, Hector; Prasad, Manika; Best, Angus Ian ORCID: https://orcid.org/0000-0001-9558-4261. 2020 Geophysical early warning of salt precipitation during geological carbon sequestration. Scientific Reports, 10 (1), 16472. https://doi.org/10.1038/s41598-020-73091-3

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Official URL: http://dx.doi.org/10.1038/s41598-020-73091-3

Abstract/Summary

Sequestration of industrial carbon dioxide (CO2) in deep geological saline aquifers is needed to mitigate global greenhouse gas emissions; monitoring the mechanical integrity of reservoir formations is essential for effective and safe operations. Clogging of fluid transport pathways in rocks from CO2-induced salt precipitation reduces injectivity and potentially compromises the reservoir storage integrity through pore fluid pressure build-up. Here, we show that early warning of salt precipitation can be achieved through geophysical remote sensing. From elastic P- and S-wave velocity and electrical resistivity monitoring during controlled laboratory CO2 injection experiments into brine-saturated quartz-sandstone of high porosity (29%) and permeability (1660 mD), and X-ray CT imaging of pore-scale salt precipitation, we were able to observe, for the first time, how CO2-induced salt precipitation leads to detectable geophysical signatures. We inferred salt-induced rock changes from (i) strain changes, (ii) a permanent ~ 1.5% decrease in wave velocities, linking the geophysical signatures to salt volume fraction through geophysical models, and (iii) increases of porosity (by ~ 6%) and permeability (~ 7%). Despite over 10% salt saturation, no clogging effects were observed, which suggests salt precipitation could extend to large sub-surface regions without loss of CO2 injectivity into high porosity and permeability saline sandstone aquifers.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	https://doi.org/10.1038/s41598-020-73091-3
ISSN:	2045-2322
Date made live:	06 Oct 2020 12:10 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/528644

Item Type:

Publication - Article

Digital Object Identifier (DOI):

https://doi.org/10.1038/s41598-020-73091-3

ISSN:

2045-2322

Date made live:

06 Oct 2020 12:10 +0 (UTC)

URI:

https://nora.nerc.ac.uk/id/eprint/528644