CCS research by the Geomicrobiology Laboratory

DNA preparation.

Molecular DNA techniques: setting up gel electrophoresis for separating microbial DNA fragments.

Led by Simon Gregory as part of the Geomicrobiology Laboratory.

The geomicrobiology laboratory collaborates with other fluid processes researchers such as Helen Taylor-Curran in the Gas Monitoring Facility and Caroline Graham in the Transport Properties Research Laboratory.

This laboratory is working on the following areas of CCS.

Surface monitoring

Although escape of CO2 is not considered likely, it is important to have detection and monitoring techniques in place should this occur.

The laboratory is trying to identify biological indicators for CO2 leaks that may help when monitoring the area around CCS sites. This will complement other techniques such as gas monitoring in the identification of CO2 leaks.

Additionally, the geomicrobiology laboratory is investigating the changes in the ecosystem at the surface of CO2 natural analogue sites and artificial injection experiments. If a storage site does leak we want to know what will happen to the ecosystem and study the changes in the microbial and plant communities. The processes involved include studying microbial diversity, numbers and activity under elevated CO2 environments.

This work makes use of both natural analogue sites where CO2 that has naturally been trapped under the ground is being released to the surface, for example through fractures in the rock. Artificial injection experiments have included both terrestrial and marine investigations. It is important to study and understand the environmental impacts of possible CO2 leaks to help with risk management planning.

Projects that involve this type of work:

  • QICS (Quantifying and Monitoring Potential Ecosystem Impacts of Geological Carbon Storage) — monitoring changes in microbial activity at a loch in Scotland that the CO2 has been injected into
  • RISCS (Research into Impacts & Safety in CO2 Storage) — monitoring the microbial numbers and activities at natural CO2 leakage sites in Greece and Italy and also at artificial injection sites in the UK

Inside the reservoir and at the injection well 

Microorganisms can grow and create biological film in different types of environments, including the deep subsurface. This laboratory is investigating microbial growth and behaviour in pressurised flow experiments using samples of reservoir rock to study biofilm growth in the conditions likely to be encountered at CO2 storage sites.

The reservoir rock is usually a sandstone from an area known to be a potential for CCS, and the pressure is set at what it would be in situ.

It is important to look at biofilms under pressure and CO2 conditions to find out whether growth is possible, where biofilms develop and whether this can impact upon the injection or storage of CO2?

There is a possibility that if biofilms develop under these conditions or if microbial induced precipitation of carbonates occurs, they could enhance the storage performance by blocking flow paths.

Further research experiments are being developed to investigate what extreme conditions biofilms will grow at, and what happens to biofilms when impurities are added to the CO2 stream.

The presence and activity of microorganisms in a CCS reservoir or pipeline has the potential to result in a number of operational issues, such as injection blockages, oil degradation and oil souring. Impurities are present within the captured gas can affect the type and amount of microbial activity that could take place. For example, the introduction of low levels of oxygen into environments which would normally have no oxygen could alter microbial activity in the storage sites.

EngD Hayden Morgan is working at the British Geological Survey with Dr Simon Gregory and Dr Keith Bateman, the University of Nottingham with Dr David Large and the industrial sponsor Progressive Energy Ltd. with David Hanstock, as part of the EPSRC Centre for Doctoral Training in Carbon Capture and Storage and Cleaner Fossil Energy. He is investigating the impacts of oxygen on microbial activity, particularly on its effects on sulphate reducing bacteria (SRB). A combination of culture based experiments and molecular approaches are being used to characterise changes in microbial communities in microcosm experiments in order to inform industry of appropriate specifications on oxygen concentration which could minimise negative microbial activity. Initial results indicate that small quantities of oxygen such as those likely to be encountered in CCS environments can support the activity of SRB. Work is now focusing on determining the level of oxygen that will minimise potentially harmful microbial activities.

Techniques for looking at biofilms at pressure: sampling the biological flow apparatus.
Molecular DNA techniques: amplifying microbial DNA using polymerase chain reactions.
Laboratory manager, Simon Gregory, looking at bacteria growing on an agar plate.