How to establish CO2 flow/concentration warning levels based on the geochemical monitoring baseline : specific case of CO2 storage at Claye-Souilly (Paris basin)

Abstract : An appropriate monitoring program proving CO2 can be stored safely for a long time is a key factor in controlling long term storage efficiency of CCS projects. A site in the Paris basin near Claye-Souilly area was identified for a future CCS pilot project. Baseline acquisition is deeply complex due to the presence of multi CO2 sources (biogas, vehicles, industrial operations, natural sources). Campaigns of measurement have demonstrated the feasibility of such strategy to detect gas transfers from subsurface equipment. Survey of CO2 storage is greatly affected by site activity and requires the development of efficient sensors in deep boreholes.