Estimation of CO2 geological storage capacity in metropolitan France ; Estimation des capacités de stockage géologique de co2 en France métropolitaine ; Estimation des capacités de stockage géologique de co2 en France métropolitaine: EVASTOCO2 (Rapport de synthèse)

The EVASTOCO2 study estimated theoretical CO2 storage capacities in European France based on the current state of knowledge and using a common methodology between the 9 partners. Depleted hydrocarbon reservoirs as well as deep saline aquifers onshore and offshore are potential storage resources. Five zones in the large sedimentary basins in mainland France were pre-targeted: 1) Atlantic Coast (the English Channel and Aquitaine Plateau); 2) Paris Basin; 3) Lorraine Basin (Carboniferous-Permian); 4) Aquitaine Basin and 5) South-Eastern Basin & Gulf of Lion. Two calculation methods based on a different volumetric formulation were used to estimate static storage capacities and the associated uncertainty (methods M1 and M2). The first method M1 based on international literature estimates the storage capacity using Storage Efficiency Factors (SEF) that depend on the lithology and scale of storage. The results using M1 allow a comparison with previous assessments carried out in France and abroad. The second method M2 based on physical parameters evaluates the storage volume available for CO2 by assuming a maximum admissible overpressure of 20 % compared with initial pressure for saline aquifers or a return to the initial pressure for depleted reservoirs.Concerning depleted hydrocarbon reservoirs, the storage capacities are onshore, mainly in the Aquitaine Basin (notably in the Lacq gas field) and for less than 2 % in the Paris Basin. These total capacities in depleted hydrocarbon reservoirs are estimated at 667 millions of tons (Mt) using the most adapted results between M1 and M2.Regarding deep onshore saline aquifers, the greatest storage potential is out of structural traps, particularly in the Paris Basin & Eastern Basin. The potential is less important in Aquitaine Basin but is estimated in traps. At this stage, there is significant but more theoretical offshore capacity, both in the Gulf of Lion and on the Atlantic coast. Using M1, these capacities are estimated at 13,026 Mt onshore and 37,195 Mt ...