Techniques for measuring liquid properties include circulating a mixed oil-water liquid flow through a fluid flow circuit; polarizing the mixed oil-water liquid flow with a pre-polarizing magnet to an initial polarization; circulating the polarized mixed oil-water liquid flow to an EFNMR detector that includes a radio-frequency (RF) coil and a surrounding electromagnet; further polarizing the polarized mixed oil-water liquid flow with the surrounding electromagnet; measuring fluid induction decay (FID) values of the additionally polarized mixed oil-water liquid flow with the EFNMR detector; transforming the measured FID values to an effective adiabatic transition from the Earth's field to the polarizing field; determining a velocity of the oil in the mixed oil-water liquid flow and a velocity of the water in the mixed oil-water liquid flow based on differences in NMR signal relaxation properties of the transformed FID values; and determining an oil content and a water content of the mixed oil-water liquid flow from the transformed FID values.