Planning deep subsurface CO2 storage monitoring for the Norwegian full-scale CCS project

Abstract

Abstract Monitoring injected CO2 is a regulatory requirement to assure safe storage and is also an important tool to optimize injection operations and confirm storage volumes. We will present the monitoring plan for the Norwegian full-scale CO2 project, particularly focusing on the subsurface monitoring. The CO2 will be injected into a deep saline aquifer at approximately 2700 m depth, located approximately 80 km offshore the western coast of Norway. Monitorability, cost and assessing leakage risk at the selected injection site were all important components in designing the optimal monitoring programme, which is aimed at proving conformance (CO2 plume behaving in accordance with predictions) and containment (no leakage out of the storage complex). The monitoring programme is separated into planned and triggered monitoring components. The planned component consists of down-hole monitoring of the well and near well area, and seismic monitoring (active and passive) of the larger subsurface area. In the case where the planned monitoring indicates non-conformance or non-containment, additional monitoring actions may be triggered. This contingency monitoring will be tailored to the specific case at hand and may consist of components of subsurface monitoring and/or of environmental surveys if there are indications of a risk of release to seabed.