Computer Axial Tomography (CAT scanning) is a valuable tool in production research because it provides the ability to nondestructively identify and evaluate the internal structural characteristics of reservoir core material systems. CAT scanning can be applied to obtain either qualitative (visual) or quantitative (numerical) data. Specific applications include core analysis and fluid flow studies. A general explanation of the instrumentation and theory is provided along with specific examples of CAT scanning applications to several reservoir core material systems.