Risk Assessment Methodology for CO 2 Storage: The Scenario Approach

This chapter introduces a “scenario approach,” which is used as a methodology for the long-term safety assessment of underground CO 2 storage and to demonstrate its applicability in an example of safety assessment. This developed methodology consists of three main parts—scenario analysis, model development and consequence analysis. The scenario analysis focuses on a comprehensive inventory of risk factors—features, events, and processes (FEPs) and subsequent selection of the most critical factors that will be grouped into discrete CO 2 leakage scenarios. Quantitative physico-mathematical models need to be developed to enable a quantitative safety assessment of the scenarios in the consequence analysis. The developed method was successfully applied to two virtual settings in the southern part of the North Sea. In these two settings two leakage scenarios are considered, leakage up a fault and through a failed well.