Porous Media Group
PhD project

Modelling and simulation of thermo-hydro-mechanical processes in fractured porous media, 2021

Ivar Stefansson

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Advisors: Inga Berre, Eirik Keilgavlen

Short description of project:

Understanding and predicting processes in fractured porous media is of wide interest, with applications such as geothermal energy extraction, water management and storage of CO2 and energy. Characterisation and monitoring are inherently challenging, and can be supplemented by modelling and simulation studies.

Strong interaction between structural features and physical processes calls for advanced models. The strong impact posed by fractures requires that they be explicitly represented in the model alongside the surrounding porous medium. Their high aspect ratio motivates a dimension reduction approach leading to a mixed-dimensional discrete fracture-matrix model. In this thesis, we consider the physical processes of fluid and heat flow and deformation of both fractures and the surrounding medium, including propagation of the former.

The model and its open-source implementation is tested in the papers constituting Part II, including benchmark studies for the flow problem and convergence studies for various parts of the model. The papers also contain simulations investigating various process-structure interaction mechanisms. Studies of fracture deformation in different regimes of thermal and hydraulic driving forces and with perturbations of various rock properties highlight the strongly coupled nature of the problem. Applications include stimulation of geothermal reservoirs and fracture propagation caused by forced and natural convection. The results demonstrate physics-based modelling's potential of advancing our understanding of complicated coupled processes.

Link to thesis at BORA-UiB.