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

作为对加热的响应，纳米级孔隙和裂缝网络的发展可以揭示与几种能源应用相关的耦合物理关系。对两个典型的热不成熟页岩样品 Kimmeridge Clay 和 Akrabou 页岩进行了延时 3D 成像和有限元建模 (FEM) 的组合，以首次研究纳米尺度的热响应。使用透射 X 射线显微镜 (TXM) 在英国钻石光源的 I13-2 光束线处以 34 nm 的体素分辨率对样品进行成像。在加热到 20°C、300°C、350°C 和 400°C 的温度后拍摄图像。随着从纳米孔到微裂缝的演变，观察并量化了单个矿物和有机物颗粒内纳米孔的形成。两个样品中孔隙体积的主要膨胀发生在 300 到 350 °C 之间，孔隙沿富含有机物的层理迅速伸长。有机质转化产生的内压影响微裂缝的发育。使用 FEM 在一系列轴向应力下对这两个样品中的机械性能和应变分布进行建模。结果表明，尽管有机质变得更硬，但页岩的整体刚度在加热过程中会降低。岩石基质中的韧性（例如粘土矿物、有机质）和脆性材料（例如方解石、黄铁矿）的不同作用也被建模和讨论。有机质、矿物成分、孔隙度和连通性的配置影响页岩热解过程中的弹性变形。