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Fig. 6. Complex variations of viscosity with asphaltene content for world’s (dead)
crudes. Apparent extrema are numbered in accordance with
asphaltene phase boundaries in Fig. 5.
Phase boundary 1 corresponds to oil’s asphaltene content of
ca. 0.001 wt% while most current databases classify all values be-
low 0.01 wt% as “zero asphaltene content”. Note that Fig. 6 shoes a
virtual absence of native free-flowing crude oils with asphaltene
contents above the phase boundary 5 which, as discussed above,
may be a natural “solubility limit” of asphaltenes in native crudes.
There is a well-known interdependence of viscosities and of
specific gravities (densities) in crude oils. Indeed, our database re-
veals noticeable peaking of specific gravities at asphaltene phase
boundaries, as shown in Fig. 7. In fact, “asphaltene nanophase” ef-
fects are so persistent, that once one starts searching for them,
they emerge even in very limited data collections. E. g., a Web site
on asphaltene deposition presents a table with “Resin and Asphal-
tene Content of various Crude Oils”.
54
The table contains proper-
ties of just ca. 20 crudes with non-zero asphaltene content from di-
verse locations (Canada, Venezuela, Mexico, USA, Russia, Brazil,
Iraq, France, Algeria).
A plot of specific gravity vs. asphaltene content for this collec-
tion of oils is shown in Fig. 8. In the absence of the above discussed
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