Robustness analysis of an uncertain computational model to predict well integrity for geologic CO2 sequestration

Abstract : Geologic storage of CO2 must respond to demonstrations of safety, control and acceptability with authorities and public. The wells are essential elements of the storage system and constitute the only man-made intrusive element in the geologic systems. The role of containment of components of wells must then be ensured for hundreds of years, despite degradation mechanisms that affect their properties. Probabilistic approaches are used to take into account the uncertainties on the quantities of CO2 which migrate from the reservoir of CO2 towards the surface and towards the aquifer. Uncertainties are taken into account by using the generalized probabilistic approach which allows both the system-parameter uncertainties and the model uncertainties induced by modeling errors to be performed in the stochastic computational model. These probabilistic tools, applied to industrial projects, allow owners and operators to set up decisions and provide a strong support to long term safety demonstration with a high level of confidence, even in presence of uncertainties in the computational models.