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| Titel |
Geochemical monitoring for detection of CO2 leakage from subsea storage
sites |
| VerfasserIn |
Maribel I. Garcia-Ibañez, Abdirahman M. Omar, Truls Johannessen |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250137627
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| Publikation (Nr.) |
 EGU/EGU2017-406.pdf |
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| Zusammenfassung |
| Carbon Capture and Storage (CCS) in subsea geological formations is a promising
large-scale technology for mitigating the increases of carbon dioxide (CO2) in the
atmosphere. However, detection and quantification of potential leakage of the stored CO2
remains as one of the main challenges of this technology. Geochemical monitoring of the
water column is specially demanding because the leakage CO2 once in the seawater may be
rapidly dispersed by dissolution, dilution and currents. In situ sensors capture CO2
leakage signal if they are deployed very close to the leakage point. For regions with
vigorous mixing and/or deep water column, and for areas far away from the leakage
point, a highly sensitive carbon tracer (Cseep tracer) was developed based on the
back-calculation techniques used to estimate anthropogenic CO2 in the water column.
Originally, the Cseep tracer was computed using accurate discrete measurements of total
dissolved inorganic carbon (DIC) and total alkalinity (AT) in the Norwegian Sea
to isolate the effect of natural submarine vents in the water column. In this work
we assess the effect of measurement variables on the performance of the method
by computing the Cseep tracer twice: first using DIC and AT, and second using
partial pressure of CO2 (pCO2) and pH. The assessment was performed through the
calculation of the signal to noise ratios (STNR). We found that the use of the Cseep tracer
increases the STNR ten times compared to the raw measurement data, regardless
of the variables used. Thus, while traditionally the pH-pCO2 pair generates the
greatest uncertainties in the oceanic CO2 system, it seems that the Cseep technique is
insensitive to that issue. On the contrary, the use of the pCO2-pH pair has the highest
CO2 leakage detection and localization potential due to the fact that both pCO2
and pH can currently be measured at high frequency and in an autonomous mode. |
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