THE USE OF NUCLEAR MAGNETIC RESONANCE TO CHARACTERIZE THE NEAR SURFACE FOR GEOPHYSICAL APPLICATIONS

Nuclear magnetic resonance (NMR) is an emerging method in near surface geophysics that allows for the direct detection of hydrogen protons in water or oil. Measurements, which can be made in the field, using a surface-based system or a borehole-logging tool, and in the laboratory, can thus provide information about the water content distribution in the region of interest. Furthermore, the NMR response is sensitive to the physical and chemical properties of the pore space, which has allowed the NMR measurement to be used to estimate porosity and permeability in saturated systems and the saturation and relative hydraulic conductivity in unsaturated systems. More recently NMR measurements have been used to monitor the chemical reactions associated with contaminant remediation. This presentation will give an overview of the use of laboratory, borehole, and surface based NMR methods for the characterization of near surface sediments. Laboratory examples will be given showing the link between NMR measurements, water content, permeability, and the chemical properties of materials. Field examples will be given showing standard applications of NMR including determining the water content with depth, as well as novel applications of NMR including determining the distribution of permafrost and monitoring contaminant remediation.