Research
My
research focuses on the use of nuclear magnetic resonance
(NMR) techniques for hydrogeologic applications. NMR methods are
directly sensitive to the abundance of hydrogen protons (water content)
in a geologic sample and convey important information about the
pore-scale physiochemical environment in which this water
resides.
The NMR response of near-surface materials
Rock physics models allow geophysicists to
relate the NMR response of a geologic material to properties of interest including pore size and permeability. Translating traditional NMR rock physics models from the oil field to the near-surfacerequires revaluating the physics governing the respone of heterogeneous and unconsolidated sediments.
+Grunewald, E and R. Knight. A laboratory study of NMR relaxation times in unconsolidated heterogeneous sediments, 76 (4), G73–G83, doi 10.1190/1.3581094
Interpretation of Earth's Field Surface NMR measurements
Borehole NMR tools use pulse sequences and large magnets to measure a refined NMR signal in a strong magnetic field (~500 gauss). Surface NMR techniques, on the other hand, rely on relatively crude pulses and perform the NMR measurement in Earth's weak magnetic field (~0.5 gauss). As a result different models are required to interpret and integrate these two classes of NMR measurements.