Monitoring CO2 Storage Sites Onshore and Offshore using InSAR Data and Strain Sensing Fibre Optics Cables

Abstract

A key requirement for geological CO2 storage is site integrity management and monitoring during operation through to the post decommissioning period. This paper focuses on monitoring deformation of the ground surface and seabed as a proxy for overall deformation in the reservoir and surrounding layers. The objective is to inform, based on deformation data, on how the reservoir is responding to CO2 injection and to ensure any issues with regard to storage integrity are rapidly detected. The magnitude and pattern of deformation at the surface reveals geomechanical/hydromechanical processes that occur in reservoir due to CO2 injection.

We acquired deformation data from the In Salah CO2 injection site and from four additional study cases during the course of this study; one in the onshore UK, the other a combined campaign onshore Norway and offshore Germany, and the third in onshore Japan. Significant developments in measurement techniques, processing tools and interpretation algorithms were developed through this project. Models were then developed to simulate the observed data and to couple surface deformation to displacement in the subsurface. The results show millimeter-scale deformations in the subsurface have a signature at the surface that can be captured by the tools and workflows developed in this project. These deformations, particularly the patterns, are important factors to consider when monitoring a CO2 storage site.

Keywords: CO2 storage monitoring, Fibre optics, Geomechanics, Injection, Offshore monitoring, Pressure, Seafloor deformation, SESE-ACT

JEL Classification: Y9