A well-logging method for a geological formation having a borehole therein may include collecting a plurality of nuclear magnetic resonance (NMR) snapshots from the borehole indicative of changes in the geological formation and defining NMR data. The method may further include identifying a plurality of fluids within the geological formation based upon the NMR data, determining respective NMR signatures for the identified fluids based upon the NMR data, determining apparent volumes for the identified fluids based upon the NMR signatures, and determining adjusted volumes for the identified fluids based upon the apparent volumes.