Surface Nuclear Magnetic Resonance Tomography

Abstract

Groundwater is the principal source of freshwater in many regions worldwide. Expensive drilling, borehole logging, and hydrological testing are the standard techniques employed in groundwater exploration and management. It would be logistically beneficial and cost-effective to have surface-based nonintrusive methods to locate and quantify groundwater occurrences and to estimate other key hydrological parameters. Surface nuclear magnetic resonance (SNMR) techniques, which are based on the spin magnetic-moment precession of protons in the hydrogen atoms of water, offer the possibility of achieving these goals. Current SNMR practices are based on 1D inversion strategies. These simple strategies impede applications of SNMR techniques in hydrologically complex areas. To address this issue, we introduce a very fast 2D SNMR tomographic-inversion scheme and apply it to four series of measurements simulated for a perched water-lens model. Whereas the new 2D scheme correctly reconstructs all important characteristics of the original model, 1D strategies produce highly inaccurate/misleading results.