Using Chemical Tracers to Verify Secure Geological Storage
RESMAN's innovative chemical tracer technology enhances CO₂ leak detection by providing highly sensitive, real-time monitoring that complements seismic data. At the Svelvik CO₂ Field Lab, this approach successfully identified leak pathways and confirmed CO₂ surface reach, advancing the safety and integrity of geological storage.
Drone photo (UiO) showing the Svelvik CO2 Field Lab . Courtesy of SINTEF (https://www.sintef.no/projectweb/svelvik-co2-field-lab/)
The safe and effective storage of captured CO₂ is a cornerstone of our efforts to combat climate change. However, ensuring that CO₂ remains securely contained underground over long periods requires robust measurement, monitoring and verification (MMV) techniques.
Seismic imaging has been the standard method for tracking CO₂ movement, providing relatively detailed images of subsurface behavior. But seismic imaging has limitations when it comes to detecting small-scale geological features like minor fractures, faults, or heterogeneities that could act as pathways for CO₂ leakage.
That’s where RESMAN is pushing the boundaries of CO₂ monitoring with innovative tracer technology. Tracers offer a highly sensitive and direct method for tracking CO₂ movement in the subsurface and to the surface, complementing seismic data and ensuring that no leaks go undetected.
Testing Tracer Technology for CO₂ Leak Detection at Svelvik CO₂ Field Lab
In 2024, we tested our High Integrity Detection System (HIDS) at the SINTEF operated Svelvik CO2 Field Lab using tracer gases co-injected with CO₂ to detect leaks from the injection site in shallow soil sampling wells.
Svelvik CO₂ Field Lab as Ideal Testing Ground
The Svelvik CO₂ Field Lab is a testing ground for this kind of cutting-edge research, designed to allow for controlled, repeatable experiments and short turnaround times, making it a perfect location for testing new monitoring methods and equipment. The facility is a small-scale field laboratory designed for testing and developing CO2 monitoring methods and equipment.
The field lab is located in a sand quarry with CO2 injection at a depth of 65 meters and is equipped with a central injection well and four surrounding monitoring wells. The geological structure has no caprock, and with the RESMAN-installed grid of shallow soil samplers— it is ideally suited for demonstration of detection of CO2 leakage to the surface.
Enabling Precise CO₂ Leak Detection with Advanced Tracer Technology
This collaboration between RESMAN and SINTEF proved that chemical tracers could play a critical role in identifying leaks and assessing the integrity of CO₂ storage sites. Tracers were detected at surface as early as one day after the start of injection, and CO₂ leaks were monitored with a tracer detection sensitivity of 100 parts per quadrillion (ppq). Nearly three months later, RESMAN’s tracers were still detectable at various locations around the site.
The HIDS utilizes chemical adsorption tubes (CATs) to collect soil gas samples from shallow depths. These samples are analyzed using state of the art advanced instrumentation in our specially designed high-sensitivity lab that was opened in 2024, enabling detection levels at extremely low concentrations. This level of sensitivity is critical for reliably pinpointing CO₂ leaks and understanding the long-term behavior of CO₂ once injected underground.
Seismic and Tracer Data: A Complementary Approach
In addition to the tracer testing, SINTEF conducted time-lapse seismic surveys, which confirmed that the bulk of the CO₂ was migrating in the same direction in the subsurface as detected in the shallow soil samples by RESMAN. However, seismic data could not determine whether CO₂ had reached the surface or how it was migrating through the geological layers.
The seismic data revealed that CO₂ migrated upwards from the injection point, accumulating under a mud layer at approximately 37 meters depth, then spreading along this partially sealing layer and moving north along the natural slope of the formation.
Tracer Data Confirms CO₂ Leak Pathways and Surface Reach
The tracer data proved invaluable, confirming that CO₂ had indeed reached the surface at multiple points and helped to characterize the path it took from the injection point.
The tracer data pattern also supported SINTEF’s geological characterization, confirming that the mud layer wasn’t fully sealing, and that CO₂ was leaking all the way to the surface. The leak pattern observed from the tracers aligned with the seismic plume data, offering a clear picture of how CO₂ was moving in the subsurface.
The collaboration between RESMAN and SINTEF has resulted in outstanding results that we are looking forward to sharing in further detail in conferences and workshops. However, the work doesn’t stop here – RESMAN will continue its efforts to improve tracer technology for CCS and MMV applications.
Working with SINTEF at the Svelvik CO₂ Field Lab in this project has been a pleasure and we recommend other companies and research groups with testing needs to consider the Svelvik CO₂ Field Lab, a part of the European ECCSEL infrastructure, for their projects.
