Wettability and fluid saturations determined from NMR T1 distributions

The abundance and distribution of brine and decane are determined from T1 distributions at different stages of a water-flood test in water-wet and oil-wet chalks. The T1 distributions generated from multi-exponential decomposition of inversion-recovery data provide more information than obtained from stretched and bi-exponential fits. Chalk samples because of their uniform pore size and ideal sedimentary rocks for NMR investigations of wettability since water and decane interactions with pore walls of differing wettability are easily distinguished.