CO2 leakage along abandoned well is one of the big risks during the process of CO2 sequestration. Especially for these abandoned and plugged wells, the availability of data is difficult, therefore well integrity evaluation for old abandoned well is a big challenge. This paper will introduce a novel risk assessment method to evaluate well integrity in CO2 Sequestration (CCS) areas. This method consists of three main steps, which are scenarios development, model development, and consequence analysis. In this paper the focus will be on the first step "FEPs and scenarios development". This method has been accepted and applied in one CCS and EGR project in a depleted gas field in Germany.