Results of investigations to design a monitoring program for a CO2 storage project in the Paris Basin (France).

Abstract: The future development of safe CO₂ storage on land needs a particular effort on monitoring methods. In the specific geological context of the sedimentary Paris Basin (France), the Géocarbone-Monitoring project carried out from 2006 to 2008 the evaluation and testing of different monitoring methods. The targeted reservoirs are either depleted reservoirs in the carbonate Dogger formation or saline aquifers in the silico-clastic formations of the Triassic. To map the migration of the CO₂ plume, the project evaluated geophysical methods as active seismic, electrical resistivity and gravity. Results show that the geological context implies further research to be conducted to overcome problems related either to data acquisition in the case of gravity or to the geological context in the case of seismic and electrical resistivity. The InSAR remote sensing method was not able to detect ground deformation over seasonal gas storage, mainly because of the dense vegetation cover. Methods for soil gas measurement at the surface were successfully tested on natural analogs, revealing the complexity of mechanisms involved in the origin of the CO₂ flux, its temporal and spatial variations, as well as the need for continuous surface measurements in order to control seasonal variations. [Copyright &y& Elsevier]