Whether sedimentary rocks store fossil hydrocarbons or act as impermeable layers to prevent the rise of oil, natural gas or stored carbon dioxide – all depends on their porosity. The size, shape, organization, and connectivity of the pore spaces are decisive. At the Heinz Maier-Leibnitz Research Neutron Source (FRM II) at the Technical University of Munich (TUM), the networks of micropores were characterized using small and very small angle neutron scattering.