Postgraduate research opportunities

Carbon geological storage: understanding micro-mechanisms of CO2 capillary breakthrough and localized pathways to assess caprock CO2 leakage hazard

The development of Carbon Capture and Storage will occur at global scale, and considering the amount of CO2 that will be captured and stored underground, long-term leakage of CO2 into the atmosphere is one of the most crucial concerns for CO2 repositories.

Number of places

1

Funding

Home fee, Stipend

Opens

9 March 2020

Deadline

22 May 2020

Duration

4 years

Eligibility

We are looking for a highly motivated person to undertake multidisciplinary research. Candidates who should have a good degree in a relevant science/engineering discipline.

Project Details

The development of Carbon Capture and Storage will occur at global scale, and considering the amount of CO2 that will be captured and stored underground, long-term leakage of CO2 into the atmosphere is one of the most crucial concerns for CO2 repositories. CO2 trapping potential of these geological repositories depends on the caprock’s low permeability to CO2. Recent field experiences have highlighted one major issue: CO2 moves through the caprock barrier much faster than expected. Several studies have suggested that this could be due to chemically-induced triggering of cracking in the clay rich rock, but previous studies have not been able to understand how the chemistry of the injected fluids may affect the micro-mechanics of the. Caprock is generally characterized by the elevated presence of clayey material. Water acidification and non-polarity of the CO2 irreversibly change the electrochemical interaction forces that dominating the clay particle configuration, which can both weaken the clay and cause it to shrink, hence, CO2 intrusion results in cracking of the caprock. Our previous research 1) showed the effect on clay microstructure for different pore water chemistries and 2) formulated a micromechanical conceptual model able to account for clay particle configuration changes caused by different chemistry of pore water (pH, fluid polarity and dielectric permittivity). This PhD studentship will focus on conducting the first micro-scale experimental investigations of crack initiation in clays, to characterize the cracking micro-mechanism occurring when exposed to CO2. Research in micro-mechanics of clayey geomaterials is lagging behind granular materials owing to the difficulty of investigating particle-to-particle interaction at the microscale. Even very basic responses observed in compression are not elucidated by basic microscale mechanisms. Characterisation of localized mechanisms such as crack initiation involves the understanding of the configuration of elements (particles) and the forces controlling the kinematics of such elements. Clay micromechanics (including the evolution of particle configuration in clays when subjected to mechanical loading) has rarely been investigated explicitly, although significant aspects of the pore space and particle configuration have been addressed by microscopic analyses such mercury intrusion porosimetry (MIP) and scanning electron microscope (SEM) testing. The proposed PhD represents an exciting opportunity to conduct fundamental research, with the prospect of having a significant impact on the assessment of the long-term CO2 trapping potential.

This PhD studentship focuses on a fundamental study on cracking mechanisms in clayey caprock upon CO2 exposure, with the aim of assessing caprock long-term sealing efficiency for CCS systems. CCS was identified by the Committee on Climate Change 2018 as the “the only way to decarbonise certain key industrial sectors” in the near future.

Funding Details

Studentships are fully funded for 4 years and cover tuition fees and stipend at the UK Research & Innovation recommended levels for each year of study.  For the 2020/21 academic session, this is £4,327 for fees and £15,009 for stipend.  Studentships also provide a generous £20,000 individual allowance to cover costs associated with pursuing the PhD over the 4-year study period e.g. conference travel, data collection, equipment purchase, travel to and from CDT training courses.  The studentship period is 4 years in order to accommodate the CDT’s bespoke 20-week residential training programme, attendance on which is a condition of acceptance of a funded CDT studentship.

Further information

This PhD will provide skills and experience to work for the oil and gas, underground gas storage and waste disposal industries. It will also fit candidates interested in pursuing further academic research.