Notícias

Porous media such as sedimentary rocks are complex materials with a pore geometry characterized by many different length scales. It is difficult to directly image the pore space with standard MRI techniques. Here, I discuss recently developed two-dimensional NMR techniques that are based on the measurement of two-dimensional diffusion – relaxation distribution functions. These measurements probe the effect of individual molecules undergoing Brownian motion restricted to the pore space. This talk reviews the principles, required instrumentation, and applications of the new technique. It will be demonstrated that these diffusion – relaxation distribution functions can be used to quantitatively identify different fluid phases, estimate the chemical composition of the fluids, and infer information on the geometry of the pore space. Compared to conventional NMR techniques, the new modality poses much weaker demands on the strength and homogeneity of the applied magnetic field. This has enabled the implementation of the new measurements on mobile inside-out systems that can investigate samples located outside the apparatus.