Carbon capture and storage (CCS) has been proposed as a powerful technology for reducing CO2 emissions and reaching international climate goals. The basic idea of CCS is to capture CO2 from industrial sources such as oil and gas production, cement industry, fertilizer production, and waste-to-energy plants, and to inject this CO2 into suitable geological fomations where it can be permanently stored.
While CO2 can be stored both on-shore and offshore, the vast majority of Norway’s storage capacity is offshore in well-studied geological formations ~1 km beneath the seabed. During the injection phase as well as the first few decades after injection, monitoring is recommended to verify that the CO2 stays inside the reservoir as intended, and to make sure that there are no negative impacts on the marine environment above the reservoir. While seismic imaging is can be used to document the extent of the injected CO2 plume in the reservoir, other technologies are suited for monitoring the marine environment. Chemical sensors can detect changes in the water geochemistry, including the concentration of CO2 and the pH level. Active acoustic sensors including sonars and echo sounders can detect bubbles as well as other features potentially related to fluid flow (pock marks, bacterial mats, changes in seabed bathymetry). Passive acoustic sensors can be placed at strategic locations to “listen” for CO2 bubbles.
Through the ACT4storage project, we aim to gain a better understanding of the capabilities and limitations of relevant acoustic and chemical technologies, for application to marine CCS monitoring (i.e., monitoring the seabed and water column above a storage site). We consider different sensor technologies individually, but we also look at how to combine data from different sensors in a meaningful way for more robust monitoring. In addition, we study the implications of mounting these sensors on different platforms including stationary templates fixed at the seabed, surface vessels, and autonomous underwater vehicles (AUVs). A controlled CO2 release experiment lasting 6 weeks was performed in the Oslo Fjord at 60 m water depth to evaluate different monitoring methods.
The project will be concluded in Q1 2020.