Deciphering the hydro-mechanical coupling and multiscale response of basaltic rocks under mineral carbonation: implications for carbon sequestration in the subsurface

Sustainable usage of the subsurface for mitigating climate change relies on multiple low-carbon solutions. CO2 sequestration has become an increasingly adopted technology, with basaltic rocks emerging as a prime target due to low upfront capital cost and the negligible risk of CO2 leakage, as it is converted into solid mineral forms. Commercial-scale applications of CO2 storage in basalt requires a thorough understanding of the mechanical response of reservoir rocks to injected CO2. This project, DECODE, aims to reveal the long-term coupled hydro-mechanical response of basalts to injected CO2 across scales. DECODE will perform state-of-the art experiments at two scales: (1) Micrometer-scale experiments in sophisticated X-ray transparent deformation rig, where the in-situ mineral carbonation process will be visualized; and (2) Centimetre scale rock deformation experiments using full-field measurements under axisymmetric and true triaxial stress conditions, to highlight the strain localization and changes in permeability during CO2 injection-induced failure. Building upon the laboratory experiments, at the meter and kilometer scales, a numerical model will be developed using the Discrete Element Method and the homogenized response of permeability associated with mineral carbonation, to better understand hydro-mechanical coupling with CO2 injection in basaltic rocks. The breakthrough of the project is to advance the understanding of reactive transport in geomaterials and to establish basalt as a safe and effective CO2 storage solution. The proposed research programme leverages the strengths of both the fellow and the host supervisor: the fellow specializes in experimental rock mechanics and deformation localization, while the host supervisor brings expertise in grain-scale modelling. This complementary expertise, combined with a well-tailored career development package for the fellow at the host university (Manchester), ensures the success of DECODE.