CO₂ Storage, Monitoring and Safety Technology

The success of geological CO₂ storage projects depends largely on the ability to monitor the state of the reservoir during and after the CO₂ injection, e.g. in terms of fluid saturation, pore pressure, and cap rock integrity. This is essential for long-term reservoir management and risk assessment. The large resistivity contrast between CO₂ and brine makes electrical methods particularly suitable for monitoring of geological sequestration projects in deep saline aquifers.

We propose electrical resistivity tomography (ERT) as a powerful tool for high-resolution time-lapse resistivty imaging. The resistivity can be interpreted in terms of the fluid stauration, yielding information about CO₂ flow paths and CO₂ dissolution in brine. The measurements will be carried out with permanent electrodes behind the borehole casing. This Vertical Electrical Resitivity Array (VERA) is deployed in the injection well and in the two observation wells of the CO₂SINK project at Ketzin. The geoelectrical data will complement the results from other geophysical methods, e. g. seismics, and will help to refine and constrain reservoir performance models.

The quantitative interpretation of the data is supported by an extensive experimental program in the laboratory under in-situ pressure and temperature conditions covering fluid properties as well as fluid-rock and fluid-cement interactions.

Work packages:

• Wellbore Integrity
• Reservoir Monitoring
• Cap Rock Integrity