Modeling the evolution of the geomechanical properties of carbonate rocks subjected to acid fluid injection

Achieving carbon neutrality targets by 2050 requires the development of significant CO2 geological storage capacities. As global capacity is not unlimited, carbonate saline aquifers, more reactive to CO2, will have to be considered as potential injection sites. Large-scale coupled thermo-hydro-mechanical and chemical simulations will be essential to confirm the viability of a storage site. The coupling of reactive transport software with geomechanical software is now feasible, but there is still a lack of appropriate laws to describe the evolution of the hydromechanical properties of the different rock formations under the effect of chemical alteration. This PhD proposes to address this issue through an integrated approach combining experimental characterization and modeling of the observed responses, with the aim of defining laws governing the evolution of the elastic moduli and failure strength of carbonate rocks exposed to acid fluids.
Carbonate rocks are characterized by a complex microstructure including different scales of porosity. Depending on the rocks studied and the reactive flow conditions applied, the dissolution patterns generated can be highly heterogeneous. Experimental approaches incorporating measurements of mechanical properties remain relatively rare, and data are often interpreted using a continuous medium approach that presupposes homogeneous dissolution. The original approach proposed here combines: (i) an advanced three-step experimental characterization workflow, including controlled alteration of carbonate samples, imaging of the induced dissolution profiles, and geomechanical characterization; and (ii) two distinct modeling approaches to interpret the geomechanical response of the altered samples depending on whether the dissolution profile is homogeneous or localized.

Keywords: CO2 storage, carbonate rocks, alteration, geomechanics, characterization, modelling

• Academic supervisor    Prof Jérôme FORTIN, Laboratoire de Géologie de l'ENS, ORCID : 0000-0002-6341-3318
• Doctoral School    ED398 GRNE, ENS-PSL
• IFPEN supervisor    Dr Elisabeth BEMER, elisabeth.bemer@ifpen.fr, ORCID : 0000-0002-0703-2406
• PhD location    IFPEN, Rueil-Malmaison, France
• Duration and start date    3 years, starting in the fourth quarter 2026 (Novembre 2)
• Employer    IFPEN
• Academic requirements    University Master degree in Earth Sciences or Engineering Sciences
• Language requirements    English level B2 (CEFR), French level B1 (CEFR)
• Other requirements    Interest in experimental and theoretical approaches, knowledge of rock mechanics and finite element modelling

To apply, please send your cover letter and CV to the IFPEN supervisor indicated here below.