PNNL

Abstract

Modeling was conducted to assess the effectiveness of the NRAP toolset, specifically NRAP-IAM-CS v2 and DREAM, to determine a risk-based PISC period and optimized monitoring network for a commercial-scale CO2 storage project. Realizations from NRAP-IAM-CS v2 revealed that leakage rates of both CO2 and brine were small, on the order of 10-5 kg/s, and occurred primarily during the injection phase in the Ironton-Galesville, the thief zone immediately overlying the injection reservoir. Using this information to design an optimized monitoring well network eliminated one of the two originally planned above zone monitoring wells, resulting a substantial cost reduction for the project. Perhaps the most significant finding from this effort is that NRAP-IAM-CS v2 can be used to define a risk-based, and substantially shorter, PISC period for the site. NRAP-IAM-CS v2 realizations indicate that the majority of risk of endagerment to USDWs decreases within the first 5 years after CO2 injection ends. Doubling this timeframe would still lead to a net PISC period reduction of 40-years and an operational cost reduction in excess of $50M for the project. This study serves as a first-of-its-kind effort to apply NRAP tools to evaluate components of a commercial-scale Class VI UIC permit and provides a foundation for broader application and adoption by the CCS community.