Ibrahim Harb – ESR 11.

About me

Recently, I graduated as a double diploma student with a Master’s degree in fluid mechanics, energetics, and thermal transfer from INSA Toulouse and a Mechanical engineering diploma from Lebanese University-Faculty of Engineering. For my master thesis, I worked an internship at IMT-Atlantique in Nantes-France in collaboration with TITANAIR Company where I worked in the flow characterization and development of smart pleated filters. Currently, I’m based in Barcelona where I’m enrolled for my Ph.D. at Amphos21 Company. 

About the project

Groundwater accounts for around 25% of the world’s freshwater supply. Due to the increasing anthropogenic pressure on shallow aquifers as well as climate change that is impacting global groundwater recharge, there is an increasing need to access deeper groundwater resources, which are typically hosted in fractured rock formations.

In fractured rocks, groundwater flow takes place along preferential flow pathways (flowing fractures) and the interaction with the host rock (i.e., minerals present in form of fracture filling or in the rock matrix) changes hydro-geochemical conditions. These processes, which include reactions such as mineral dissolution and precipitation, trace element sorption and exchange, and microbial metabolism, have the potential to alter groundwater flow patterns. Thus, there is evident feedback between reactive transport and the underlying distribution of fracture openings.

Deep fractured formations are important for a broad range of applications including energy storage (e.g., H2), the disposal of hazardous wastes (e.g., nuclear-spent fuel) as well as the production of drinking water in dry areas. It turns out that the prediction of the interaction between host rock formations and inflowing fluids becomes critical for their proper management. Therefore, the understanding and modeling of fluid-fracture interaction are of high scientific and commercial interest. However, due to the high computational requirements of the underlying calculations, reactive transport models in fractured networks are still at an incipient stage.

In this ESR project within Fluid-Net, I will work in expanding and improving the assessment of fracture evolution due to geochemical reactions, through a Discrete Fracture Network representation using High-Performance Computing technologies and an available open-source DFN simulator (dfnWorks). The results of the study are expected to be of interest for applications such as the safety assessment of deep geological spent nuclear fuel repositories or for the design of optimal remediation strategies. Thus I should study how fractured granitic rocks are affected by water-rock interaction, understand how mineral dissolution/precipitation processes impact hydrological patterns at a large scale (i.e., the scale of interest for a safety assessment study for deep geological disposal of nuclear waste), and understand how fracture evolution, due to water-rock interaction, affects the potential of the rock to retain harmful radionuclides potentially released due to repository failure.

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