This educational webinar explores how critical pressure informs the definition and refinement of a carbon sequestration project’s Area of Review (AoR) under the Class VI permitting framework. The SCS experts explain why some developers are re-evaluating AoR assumptions, how injection-driven pressure propagation can dominate AoR extent, and why project-specific geology (including fluid salinity and basin structure) can make simplified approaches overly conservative, rather than safer.
In this 17-minute session, we compare calculation approaches (Methods 2, 2A, and 3) and emphasize that early, iterative AoR work can reduce regulatory, cost, and public-trust risks.
AoR must account for both plume extent and pressure effects: Beyond the supercritical CO2 plume, pressurization and project critical pressure determine where fluids could migrate upward through improperly plugged/abandoned wells and potentially endanger underground sources of drinking water (USDWs).
Pressure front propagation is often the controlling factor: Pressure can propagate faster and farther than the mobile plume, and may be altered by geologic structures (e.g., faults).
Fluid salinity and density matter: Higher salinity increases fluid density and generally requires more induced pressure to drive vertical migration; real-world salinity profiles can be non-linear and project-specific.
Method selection depends on data and realism: Method 2 is simple but can yield unrealistic outcomes (e.g., zero/negative critical pressure). Method 2A uses a more detailed equation-of-state approach. Method 3 incorporates risk-based computational modeling of flow through a hypothetical, poorly-plugged well and can better handle complex cases.
Timing and iteration reduce downstream costs: Investing early and periodically re-evaluating AOR assumptions improves defensibility and can avoid costly changes after permitting.
Transparency supports outreach: The AoR process and re-evaluations (including public comment opportunities) can be communicated in plain language to build public confidence in drinking water protection.
