Dispersion of T1 and T2 Nuclear Magnetic Resonance Relaxation in Crude Oils |
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| Authors: | Joseph J Chen Dr Martin Hürlimann Dr Jeffrey Paulsen Dr Denise Freed Dr Soumyajit Mandal Dr Yi‐Qiao Song |
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| Institution: | 1. Schlumberger‐Doll Research, One Hampshire Street, Cambridge, MA, 02139 (USA);2. Department of Chemical and Biomolecular Engineering, University of California, Berkeley, CA, 94703 (USA) |
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| Abstract: | Crude oils, which are complex mixtures of hydrocarbons, can be characterized by nuclear magnetic resonace diffusion and relaxation methods to yield physical properties and chemical compositions. In particular, the field dependence, or dispersion, of T1 relaxation can be used to investigate the presence and dynamics of asphaltenes, the large molecules primarily responsible for the high viscosity in heavy crudes. However, the T2 relaxation dispersion of crude oils, which provides additional insight when measured alongside T1, has yet to be investigated systematically. Here we present the field dependence of T1‐T2 correlations of several crude oils with disparate densities. While asphaltene and resin‐containing crude oils exhibit significant T1 dispersion, minimal T2 dispersion is seen in all oils. This contrasting behavior between T1 and T2 cannot result from random molecular motions, and thus, we attribute our dispersion results to highly correlated molecular dynamics in asphaltene‐containing crude oils. |
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| Keywords: | aggregation crude oil NMR spectroscopy petrophysics relaxation dispersion |
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