[Internship postion] Similitude analysis of chemo-mechanical phenomena in CO2 geological sequestration

Institute GeM is a Joint Research Unit supervised by Nantes Université, Centrale Nantes and the CNRS. Founded in 2004, the objective was to bring together within the same laboratory all the skills in the Nantes Saint-Nazaire area in the fields of civil engineering, materials and processes, modelling and simulation in structural mechanics.

The mission of our research institute is to propose innovative manufacturing processes and simulation tools adapted to the dimensioning and life cycle management of products, structures and works, taking into account the influence of severe stresses and environmental actions.

The research carried out at GeM is balanced between advanced and applied research. The unit is characterised by its significant and differentiating testing resources, with several technological platforms: civil engineering (test slab, durability characterisation, environment), manufacturing (bio-printing and additive manufacturing, composite processes), materials (X-ray diffraction, composite durability), structures (membrane structures, static and dynamic tests)

The projects are conducted in close collaboration with industry, project owners and companies specialising in mechanical and civil engineering. It is also the subject of scientific collaboration with other French and foreign research centres, in particular as part of European programmes or networks.

Context & problem statement

According to The Intergovernmental Panel on Climate Change (IPCC) AR6 synthesis report 2023, the global modelled pathways that limit global warming to 2°C or below depend on almost all electricity being supplied from net-zero or low-carbon sources by 2050. These sources include renewables or fossil fuels accompanied CO2 capture and storage (CCS). CCS in deep geological formations has consequently emerged as an important option to reduce greenhouse gas emissions and CCS facilities are continuing to grow in Europe. The current  internship subject is part of the larger project LOCCO “hydro-chemo-mechanical LOCalization phenomena in CO2 geological sequestration” financed by ANR (Agènce Nationale de la Recherche) in France which aims at releasing scientific bottlenecks in this domain. The target is to increase the knowledge pool on the interaction between the CO2 injected in geological storage reservoir (aquifer rock) and the surrounding rock (caprock), where the latter should act as sealing barrier to the CO2 migration and leakage, thus guaranteeing long-term storage security. 

It is well known that the injected CO2 creates an acidic solution by dissolving in brine saturating the aquifer rock. Such solution could be subject to diffusion and percolation through the sealing caprock and potentially reacts with the mineral inclusions (Calcite among others) causing local dissolution of the caprock. Significant modification of mechanical (stiffness and strength characteristics) and hydraulic properties (permeability) could be observed depending on the level of mechanical confinement.

Scientific approach & internship objectives

While few experiments are available in the literature, the main goal of this internship project is to work on suitable similarity laws that allow to investigate diffusivity phenomena occurring at the interface between the aquifer and the caprock, at the scale of the geological reservoir. Laboratory scale tests, developed on prototype clay matrix with Calcite inclusions, will be carried out under much lower mechanical confinement than the in-situ stress in a caprock to characterize the effect of H+ cation diffusion. Progressive dissolution of Calcite inclusions is expected to occur. The purpose of the internship research is to get an estimate of Calcite dissolution rate. This result will be achieved identifying similitude conditions between the prototype and the model problem (the one tested at the laboratory scale) on the basis of suitable dimensionless numbers. A minimal experimental setup will be designed and realized for this purpose. Preliminary measure of diffusivity coefficient through pure water and through water saturated Clayey media will also be realized in order to get an estimate of the characteristic time of the diffusion processes.

During the internship, the student will apply skills acquired in porous media mechanics, similitude analysis, be able to collaborate with a dynamic research group & have the opportunity to learn from leading researchers.

Internship advisors

• Giulio SCIARRA (Professeur des Universités), Institut de Génie Civil et Mécanique (GeM), Ecole Centrale de Nantes
• Siddhartha Harsha OMMI (Maître de Conférences), Institut de Génie Civil et Mécanique (GeM), Ecole Centrale de Nantes

Additional information

• The internship will be conducted in its entirety at the Institut de Génie Civil et Mécanique (GeM), Ecole Centrale de Nantes, 1, rue de la Noë, 44321 Nantes cedex 03, FRANCE.
• The internship will start on 23 February 2026 and lasts 6 months (possible extension to a PhD thesis).
• The gratification will be 4.35 €/hour (≈ 600 €/month) according to the French law.
• The internship is funded by the Projet LOCCO (ydro-chemo-mechanical LOCalization phenomena in CO2 geological sequestration) financed by the ANR (Agènce Nationale de la Recherche, France).

Required competences:

• We are looking for an enrolled master student in Civil Engineering, Mechanical Engineering or Environmental Sciences being interested in experimental applied research activities.
• Familiarity with experimental apparatus in Civil engineering laboratory is an advantage.
• Fluent in written/spoken English.