Modelling the impact of rock fractures, alteration, and mineral composition on rock properties in deep geothermal context

Topic description

Context:

The propose study addresses socio-economic and environmental challenges of using soil and subsoil resources, particularly in the context of the energy transition. Nowadays, a key focus is on deep geothermal energy, which relies on the ability of underground rock formations to store and transmit thermal fluids effectively. High-enthalpy geothermal systems depend on the quality of reservoir rocks, which is governed by, for instance, their porosity, fracture structure, permeability, and fluid circulation. All of which are influenced by the rock structure and mineral composition, as well as its possible evolution. This is particularly the case for rock-fluid interaction in porous or fractured rocks, possibly leading to rock damage, alteration, and porosity/mineral variation (e.g. dissolution, precipitation, etc.). For instance, the precipitation of minerals (e.g. clay) tends to reduce hydraulic permeability, affecting fluid circulation and the efficiency of geothermal systems.

Objectives and method:

The main objectives of the research are to:
- Integrate fracture structure and mineral composition into the assessment of hydromechanical rock
properties.
- Model the evolution of mineral content due to alteration processes.
- Predict the impact on reservoir behaviour and geothermal production at larger scales.

To achieve this, the study will develop a theoretical and numerical multiphysical (TH(MC)) model that links microstructural properties to macroscopic rock behaviour. This geomechanics and rock mechanics work will be realised using finite element modelling approaches (e.g. Comsol MultiPhysics).

Funding category

Public/private mixed funding

Funding further details