GEOPHYSICAL DATA FOR MULTIPHYSICS SPARSE NODE-BASED CO2 STORAGE MONITORING

Abstract Monitoring CO2 storage sites over decades requires cost-effective, reliable strategies to ensure containment and conformance. Conventional approaches such as repeated 3D/4D seismic surveys are expensive and logistically challenging, particularly offshore. The SPARSE project, developed under ACT4, introduces a sparse nodebased multiphysics monitoring concept that integrates seismic, electromagnetics, gravity, and deformation measurements. This approach is designed to reduce survey frequency while maintaining sensitivity to pressure and saturation changes. We present results from onshore field trials at Carbon Management Canada’s Newell County site and offshore feasibility studies based on the Smeaheia CO2 storage model. Onshore tests demonstrate the feasibility of using permanent seismic sources, distributed acoustic sensing, and electromagnetic configurations within a sparse monitoring framework. Offshore modeling indicates that seismic, electromagnetic, and gravity signals can detect plume arrival, monitor its development over time, and distinguish between different migration scenarios under realistic noise conditions. These findings support the feasibility of sparsenode multiphysics monitoring as a scalable and costefficient approach for longterm CO2 storage assurance, complementing conventional methods and informing future deployment.