1. Introduction and Background 2. Fundamental Theory in Small Angle Scattering: X-ray and Neutron 3. X-ray and Neutron Scattering Facilities across the Globe 4. Pore accessibility Characterization for Natural Rocks 5. Pore structures and Fluid Behaviors in Geomaterials 6. Connections between Small Angle Scattering and Other Techniques and the Application in Geomaterials 7. Outlook