Nuclear magnetic resonance measurements of wettability and fluid saturations in chalk

The surface-sensitive nature of proton NuclearMagnetic Resonance (NMR) relaxation makes it<br>an ideal probe to determine changes in wettability and fluid saturations of both experimentally altered<br>outcrop chalk and preserved-state reservoir chalk. The transformation of standard<br>NMR inversion-recovery data into a distribution of relaxation times clearly indicates the effect<br>of altering original wettability by significant shifts in the populations of relaxation times<br>observed in samples saturated with either water or hydrocarbon phases. Population densities<br>for the relaxation time components associated with both fluids correlate quantitatively with more<br>traditional volume displacement measures of fluid saturation.