  Convection-driven cooling in porous media influences thermo-poro-mechanical
stresses, thereby causing deformation. These processes are strongly influenced
by the presence of fractures, which dominate flow and heat transfer. At the
same time, the fractures deform and propagate in response to changes in the
stress state. Mathematically, the model governing the physics is tightly
coupled and must account for the strong discontinuities introduced by the
fractures. Over the last decade, and motivated by a number of porous media
applications, research into such coupled models has advanced modelling of
processes in porous media substantially.
  Building on this effort, this work presents a novel model that couples flow,
heat transfer, deformation, and propagation of fractures with flow, heat
transfer, and thermo-poroelasticity in the matrix. The model is based on
explicit representation of fractures in the porous medium, and discretised
using multi-point finite volume methods. Frictional contact and non-penetration
conditions for the fractures are handled through active set methods, while a
propagation criterion based on stress intensity factors governs fracture
extension. Considering both forced and natural convection processes, the
numerical results show the intricate nature of thermo-poromechanical fracture
deformation and propagation.
