The CO2-Vadose project: Experimental study and modelling of CO2 induced leakage and tracers associated in the carbonate vadose zone

The CO2-Vadose project aims at: (i) understanding the behaviour of CO2 in the near surface carbonate environment during an induced CO2 leakage, (ii) assessing numerical simulations associated with CO2 release experiments, (iii) developing integrated field methodologies to detect and quantify a potential CO2 leakage. A gas mixture of CO2 with He and Kr was released in a cavity (9 m(3), 7 m deep) located in an abandoned limestone quarry in France. Different gas measurement techniques were used to follow the plumes diffuse migrations in the carbonate vadose zone. A first gas release experiment with Ar and He was performed for checking and validating the experimental protocol. Then, the experimental CO2 and tracers induced leakage was performed to study the gas migration in the vadose zone. The numerical simulations done with COORES (TM) code, associated with the experiment to describe the plumes extensions, were in good agreement near the source. The results show that CO2 subsurface leakage can be anticipated thanks to inert gases used as tracers, like He and Kr. As part of a monitoring plan, the detection of noble gas increase could lead to the surveillance of the monitored area with accuracy. (C) 2013 Elsevier Ltd. All rights reserved.