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Title: Radiocarbon as a Reactive Tracer for Tracking Permanent CO2 Storage in Basaltic Rocks

In view of concerns about the long-term integrity and containment of CO2 storage in geologic reservoirs, many efforts have been made to improve the monitoring, verification and accounting methods for geologically stored CO2. Our project aimed to demonstrate that carbon-14 (14C) could be used as a reactive tracer to monitor geochemical reactions and evaluate the extent of mineral trapping of CO2 in basaltic rocks. The capacity of a storage reservoir for mineral trapping of CO2 is largely a function of host rock composition. Mineral carbonation involves combining CO2 with divalent cations including Ca2+, Mg2+ and Fe2+. The most abundant geological sources for these cations are basaltic rocks. Based on initial storage capacity estimates, we know that basalts have the necessary capacity to store million to billion tons of CO2 via in situ mineral carbonation. However, little is known about CO2-fluid-rock reactions occurring in a basaltic storage reservoir during and post-CO2 injection. None of the common monitoring and verification techniques have been able to provide a surveying tool for mineral trapping. The most direct method for quantitative monitoring and accounting involves the tagging of the injected CO2 with 14C because 14C is not present in deep geologic reservoirs prior to injection.more » Accordingly, we conducted two CO2 injection tests at the CarbFix pilot injection site in Iceland to study the feasibility of 14C as a reactive tracer for monitoring CO2-fluid-rock reactions and CO2 mineralization. Our newly developed monitoring techniques, using 14C as a reactive tracer, have been successfully demonstrated. For the first time, permanent and safe disposal of CO2 as environmentally benign carbonate minerals in basaltic rocks could be shown. Over 95% of the injected CO2 at the CarbFix pilot injection site was mineralized to carbonate minerals in less than two years after injection. Our monitoring results confirm that CO2 mineralization in basaltic rocks is far faster than previously postulated.« less
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  1. Columbia Univ., New York, NY (United States)
Publication Date:
OSTI Identifier:
DOE Contract Number:
Resource Type:
Technical Report
Research Org:
The Trustees Of Columbia University In The City Of New York Inc., NY (United States)
Sponsoring Org:
Country of Publication:
United States
01 COAL, LIGNITE, AND PEAT; 15 GEOTHERMAL ENERGY; 20 FOSSIL-FUELED POWER PLANTS; 54 ENVIRONMENTAL SCIENCES; 58 GEOSCIENCES Monitoring; verification and accounting; CO2 mineralization; CarbFix; radiocarbon; sulfurhexafluoride; trifluoromethyl sulfur pentafluoride