The inversion of surface-NMR T1 data for improved aquifer characterization

ABSTRACTA crucial component in sustainable freshwater management is the reliable and cost-effective characterization of groundwater aquifers. A technique that allows noninvasive characterization of shallow (<100  m) aquifers is surface nuclear magnetic resonance (surface NMR). The measured parameter longitudinal relaxation time T1 provides a link to pore-scale properties and can be used to estimate the hydraulic conductivity of the sampled region. The recent development of an optimized acquisition scheme, phase-cycled pseudosaturation recovery (pcPSR), has significantly advanced our ability to acquire surface-NMR T1 data. Building on these findings, we developed an inversion scheme that can reconstruct the depth-distribution of T1 from pcPSR data. To stabilize the inversion, we took a staggered approach: We first determined the distribution of water content and effective transverse relaxation time T2*, and then we resolved the T1 structure. We tested the capability of the inversion in a synthetic study us...

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