| Autor: |
Mullins, Oliver C., Sheu, Eric Y., Hammami, Ahmed, Marshall, Alan G., Freed, Denise E., Lisitza, Natalia V., Sen, Pabitra N., Yi-Qiao Song |
| Zdroj: |
Asphaltenes, Heavy Oils & Petroleomics; 2007, p279-299, 21p |
| Abstrakt: |
We discuss examples and methods for using NMR diffusion measurements to obtain information about molecular sizes, their distributions, and dynamics. Scaling relationships between chain lengths and diffusion constants are derived and tested on diffusion measurements of many samples, including crude oils that are high in saturates. The diffusion constants of asphaltenes are also measured as a function of asphaltene concentration, indicating the formation of asphaltene aggregates at a concentration of approximately 0.2 g/L, and the sizes of the individual asphaltene molecules and aggregates are obtained. The examples and methods discussed in this paper can become the basis for in situ characterization of crude oils. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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