Joint x-ray and neutron tomography of shale cores for characterizing structural morphology

To better model the storage and flow of gas and light hydrocarbons in shales, it is necessary to quantify the structural distributions of organic and inorganic components and fractures in shales over a large range of length scales. The combination of neutron and X-ray tomography provides these distributions on the core scale, in contrast to most current μm-scale SEM studies. We present a new conjoint X-ray and neutron computed tomography (CT) for 3D shale-core characterization. Neutrons are attenuated significantly by hydrogen compared with most other elements. Therefore, the hydrogen-rich areas, i.e., organic matter can be easily distinguished from fractures and inorganic, hydrogen-poor matter. On the other hand, X-rays are attenuated more when the atomic number Z of the element is larger and can be used to identify high-Z elements such as minerals. Therefore, combining X-ray and neutron tomography can provide much more comprehensive information of shale. The combination of neutron and X-ray tomography allows one to identify different minerals, fractures, and organic matter for improved and more realistic representation of the rock 3D structure.