SENSE; Assuring integrity of CO₂ storage sites through ground surface monitoring

The SENSE project is based on the use of monitoring technology and methods to connect surface elevation to hydromechanical processes that take place in the reservoir. The project develops measurement techniques that capture small movements (mm scale) on land and in the seabed and performs such measurements in four different case studies. These movements are connected to the reservoir pressure through geomechanical models and inversion methods. The aim is to conclude whether CO₂ in the reservoir is moving as expected or if something abnormal is happening and thus give an alarm signal to the operator.

The main goal is to test techniques for continuous measurement of “ground motion”, develop methodologies for connecting such measurements to mechanical events in the reservoir and offer operators cost-effective methods for monitoring and safe storage of CO₂.

To achieve these goals, we use four case studies:
1) Hatfield Moors in England. Hatfield Moors is a sandstone reservoir for storing natural gas in summer and producing the same in winter. One can expect the surface to correspond to pressure build-up in summer and depletion in winter. We have placed Corner-Reflectors on site and collect satellite data to analyze the relationship between pressure changes in the reservoir and surface movements.
2) In Salah CO₂ storage site in Krechba, Algeria. For In Salah, we study post-injection data to see how the surface reacts a few years after the injection was stopped.
3) Boknis Eck offshore site in Kiel, Germany. Boknis Eck in Germany is a place where we perform full-scale experiments and measure movements on the seabed that occur either due to injection or simulated removal of the seabed. There we look at accuracy of instruments, data noise, and other practical issues for the use of these methods in offshore.
4) Gulf of Mexico. Here we use geological and geophysical data in different scenarios of CO₂ injection and estimate movement on the seabed through geomechanical modeling and thereby we propose technologies that can be used for monitoring reservoirs in the Gulf-of-Mexico.

SENSE has 14 partners from 9 countries: Equinor, NGI, Quad Geometrics and UiO from Norway, GEOMAR from Germany, British Geological Survey (BGS) from the UK, IFPEN from France, CIUDEN and Spanish Geological Survey (IGME) from Spain, Lawrence Livermore National Laboratory (LLNL) and University of Texas, Austin from USA, Research Institute of Innovative Technology for the Earth (RITE) from Japan, CSIRO from Australia and KIGAM from South Korea.

The project is funded by ACT (Accelerating CCS Technology) at Gassnova in Norway, BEIS in the UK, ADEME in France, JULICH Forschungszentrum in Germany, U.S. Department of Energy and AEI in Spain. EkstraSENSE has also received industry funding from Equinor. The project period is from 1 September 2019 to 31 August 2022.