Abstract
Controlled‑source electromagnetic (CSEM) monitoring offers a potential cost‑effective solution for measurement, monitoring, and verification of CO₂ storage. This study integrates geological modelling, reservoir simulation, rock physics, and CSEM modelling within a decision‑analysis framework to evaluate monitoring strategies for the Smeaheia CO₂ storage site. Two geological scenarios, with and without thin intra‑sand shale layers, are investigated and shown to produce distinct CO₂ migration patterns and electromagnetic responses. Survey optimization and value‑of‑information analysis demonstrate how optimized CSEM acquisition geometry and timing can reduce monitoring costs while supporting robust decision‑making under stratigraphic uncertainty.