Abstract The potential use of NMR as a direct indicator of hydrocarbon saturation via techniques such as the Differential Spectrum Method (DSM) has generated significant interest in the petrophysical community in recent years. Although originally developed for applications involving natural gas, the DSM has also been used successfully in light hydrocarbon environments. However, success has been limited to the low end of the viscosity spectrum because of the T1 separation requirements between the brine and hydrocarbon phases. The T1 separation requirement in higher viscosity applications can be eliminated by using the Enhanced Diffusion Method (EDM), where diffusion is turned into the dominant relaxation mode for the wetting brine phase. Given that brine is more diffusive than the hydrocarbons, the longest apparent T2 from the brine phase can be made short enough to cause separation between the two phases in T2 space, thereby eliminating the need for T1 separation. Wait time manipulation can then be used to quantity hydrocarbon volumes when the two phases are separated in T2 domain. This paper focuses on the determination of residual oil saturation using EDM, while also providing guidelines for job screening and acquisition parameter selection. Several case histories provided are used to illustrate basic concepts and different methodologies available. P. 267