We present a discussion of the use of NMR in the characterization of heavy oils and oil sands and their interactions with water and solid surfaces. The phenomena probed by the NMR techniques take place over different length scales, ranging from molecular, through colloidal to macroscopic. During the course of the last 15 years, NMR applications have grown from their initial use in studying conventional oils in rocks to the characterization of more viscous oils in unconsolidated porous media. In particular, (1)H NMR relaxometry and diffusometry are considered with a view to the identification of oil and water in oilfield fluids and their environment. After some theoretical considerations, various topics of current significance to petroleum recovery and production are discussed, including oil viscosity (with new experimental viscosity correlations added), oil sands characterization, heavy oil emulsions, and the identification of solvent effects on oil components and asphaltene solution behaviour and interactions. We show that, increasingly, NMR is becoming an invaluable and versatile characterization tool in petroleum science, in both laboratory and field.
Keywords: Asphaltenes; Heavy oil; NMR; Oil sands; Viscosity; Wettability.
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