Modeling the long-term isolation performance of natural and engineered geologic CO2 storage sites

Abstract

The success of engineered geologic CO2 storage hinges on the ability to identify optimal sites and forecast their long-term security. This ability relies upon predictive models for assessing the relative effectiveness of CO2 migration and sequestration processes (isolation performance) as a function of key target-formation and cap-rock properties (screening criteria). It also relies on detailed knowledge of naturally occurring CO2 reservoirs and clear understanding of the extent to which they represent natural analogs to engineered storage sites. Among key screening criteria, long-term cap rock integrity represents the single most important constraint on long-term isolation performance, and among predictive methodologies, the reactive transport modeling approach is uniquely well suited to quantify this fundamental constraint for both natural and engineered settings.