Development and Application of BowTie Risk Assessment Methodology for Carbon Geological Storage Projects

The objective of this research is to develop a framework for risk assessment of CO2 geological storage projects. This is achieved using the BowTie approach as a framework for capturing the failure of CO2 geological storage, and using BowTie approach to combine different failure mechanisms such as wellbore leakage and caprock leakage in a linguistic manner. One of the major difficulties in expert judgment is subjective and dispersed opinion around risk. This research attempts to define dispersed opinions as experts plan knowledge level over different risk hazards by using the Dempster-Shafer theory. In this study, belief on experts’ judgments propagate through the right hand side of the BowTie structure (which is fault tree structure) using Boolean algebra and the Dempster-Shafer theory, while expert-evaluated index on caprock and wellbore propagate through the fault tree section of the BowTie structure using fuzzy logic theory. Finally, risk and belief are combined to assign different belief values to different evaluations of calculated risk values. In this study, the concept of fuzzy logic is explored as one approach to characterizing the risks associated with CO2 storage in the Weyburn project. The Weyburn-Midale CO 2 Monitoring and Storage Project is considered sufficiently well documented to demonstrate the applicability of fuzzy set theory to risk assessment of carbon sequestration projects. Public data available for the International Energy Agency Greenhouse Gas R&D Programme (IEA GHG) Weyburn-Midale CO 2 Monitoring and Storage Project is used for modelling and to assess the applicability of the proposed approach.