Micromechanics of Gas Transport and Fracturing in Caprock and Clay Barriers for geological storage of CO₂ and geological disposal of nuclear waste (fully funded for candidates with UK citizenship or EU citizenship with pre-settled or settled status)

About the Project

Project Overview

Clay-rich rocks such as mudstones and shales are widely used as natural and engineered barriers to gas flow—whether to seal geological storage sites for carbon dioxide, contain radioactive waste, or isolate energy gases such as hydrogen or methane. Their extremely low permeability makes them attractive as long-term seals, but recent evidence has shown that gas injection under pressure can lead to unexpected transport behaviour and cracking, even in the most impermeable formations.

This PhD project will investigate the microscale mechanisms governing gas transport and crack initiation in clay barriers and caprock formations, with the goal of improving our understanding of their long-term sealing performance in subsurface energy and waste storage applications.

The Challenge

When gases are injected into deep geological formations, they are often stored beneath a low-permeability caprock that acts as a natural seal. These seals rely on the assumption that gas cannot penetrate the rock’s fine pores due to high capillary entry pressures. However, recent field and laboratory data suggest that gas migration can occur at much lower pressures than expected, and in some cases gas moves not through pore networks, but through newly formed microcracks. This behaviour undermines the long-term integrity of storage systems and calls for a deeper understanding of the material response at the particle scale.

Key questions remain unanswered:

• What triggers crack formation in dense clays under gas pressure?
• How do pore water chemistry, gas type, and particle-scale forces interact?
• What are the conditions under which capillary flow transitions into fracture-driven flow?

This project addresses these questions through experimental investigation and micromechanical modelling of gas-clay interactions under realistic subsurface conditions.

Research Aim

The aim of the PhD is to investigate the micromechanical processes that govern gas transport and fracture development in clay-rich barriers.

Who Should Apply

We welcome applicants with backgrounds in:

• Geotechnical or Civil Engineering
• Geology or Geoscience
• Soil Mechanics or Clay Mineralogy
• Environmental Engineering or Hydrogeology
• Materials Science, Physics, or Chemistry

Curiosity about coupled chemical–mechanical processes, subsurface energy systems, or clay behaviour is essential. Prior lab or modelling experience is beneficial but not required—training will be provided.

Make a Global Impact

Join a research team at the forefront of energy and environmental geomechanics. This PhD offers the opportunity to contribute to safer energy transitions, sustainable waste disposal, and climate change mitigation—by revealing the hidden behaviours of some of Earth’s most complex materials.

Funding Notes

Candidate Requirements

1. First class, or strong upper second class, honours degree in Geotechnical Engineering, Civil Engineering, Structural Engineering, Physics, Chemistry, Soil Science, Geoscience, Geology or other relevant discipline
2. UK citizenship or EU citizenship with pre-settled or settled status

Please, note that we will not reply to candidates who do not meet eligibility criterion #2.