6.4.5 Planned storage project - Decatur Project in Illinois, USA

Schlumberger Carbon Services (a service provider for carbon dioxide capture and storage; measurement, monitoring, and verification; and risk assessments) recently presented an example of a risk for a planned storage project in Illinois (Hnottavange-Telleenet al., 2009). To develop this risk, Schlumberger convened a group of experts to rank a list of more than 80 risk elements - or features, events, and processes (FEPs) - based on 'likelihood' (L) and 'severity' (S). These rankings were developed through a group process and independent surveys of the experts. The rankings were assessed through two methods. First, the team developed a combined (L*S) ranking and compared group and individual ratings. Second, the team mapped FEPs on a grid, with severity on the vertical axis and likelihood on the horizontal axis. These approaches provide the project team with a good assessment of concerns that could arise at the specific site and will enable them to both incorporate those risks into the reservoir models and also to mitigate those risks through careful planning and operations. Results are being used to rationalize and shape risk-reduction measures, especially those involving well engineering and subsurface characterization (WRI, 2008; Hnottavange-Telleenet al., 2009). This kind of assessment also helps the team to design a monitoring plan and interact with the public and regulators. It is important to note that this kind of assessment can be repeated over time; it is not a static analysis (WRI, 2008). Risk evaluation influences plans for monitoring and external communications, and informs the construction and quantitative attribution of flow simulations and system models (Hnottavange-Telleenet al., 2009). The project in Illinois is a qualitative ranking case study.