Spatially Resolved Dynamic Longitudinal Relaxometry in Single-Sided NMR

Relaxation in nuclear magnetic resonance (NMR), both transverse and longitudinal, provides information on microscopic features of a wide variety of systems and may be used to monitor dynamic processes such as cementation, chemical reactions, gelatinization, and evaporation. Dynamic relaxometry, in combination with spatial resolution, is a useful technique that provides deep insight into complex systems evolution. In this work, we explore the range of applicability of single-sided NMR to determine the evaporation kinetics of fluid from porous media. We show that, due to technical experimental restrictions, the determination of the time-dependent amount of fluid in different voids as a function of the position is in general not feasible with transverse relaxation experiments. However, as opposed to common intuition, longitudinal relaxation experiments provide reliable and fast acquisition, compatible with the requirements needed to monitor a water evaporation process from a model oil-reservoir rock sample.