Time-lapse nanometre-scale 3D synchrotron imaging and image-based modelling of the response of shales to heating

The development of pore and fracture networks at the nano-scale as a response to heating can reveal coupled physical relationships relevant several energy applications. A combination time-lapse 3D imaging finite-element modelling (FEM) was performed on two typical thermally immature shale samples, Kimmeridge Clay Akrabou shale, investigate thermal nm-scale for first time. Samples were imaged using Transmission X-ray Microscopy (TXM) with voxel resolution 34 nm I13–2 beamline Diamond Light source, UK. Images taken after temperatures 20 °C, 300 350 °C 400 °C. initiation nano-pores within individual minerals organic matter particles observed quantified alongside evolution from micro-fractures. major expansion pore-volume occurred between in both pores elongating rapidly along organic-rich bedding. internal pressures induced by transformation influenced microfractures. Mechanical properties strain distributions these samples modelled under range axial stresses FEM. results show that overall stiffness reduced during heating, despite becoming stiffer. varied roles ductile (e.g., clay minerals, matter) brittle materials calcite, pyrite) rock matrix are also discussed. configurations matter, mineral components, porosity connectivity impact elastic deformation pyrolysis. This work extends our understanding dynamic processes microstructure shales nm-scale, which has applications other subsurface systems such carbon sequestration, geothermal nuclear waste disposal.