Нефтегазовые нанотехнологии для разработки и эксплуатации месторождений. Часть 3. Евдокимов И.Н - 48 стр.

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upper and lower layers strongly diverge, apparently due to an ap-

pearance of a significant concentration gradient (or, possibly, due

to some sort of a phase separation in the multicomponent crude).

Our studies [15] have shown that an absorptivity of an oil/toluene

solution is determined mainly by the concentration of asphaltenes

in the original crude oil sample.

Accordingly, the results of Fig. 4 for 36°C indicate that an as-

phaltene content increased in the lower-density upper oil layers

and decreased in the higher-density bottom layers. An unexpected

enrichment of upper oil layers with asphaltenes, possessing high

molecular weights, may be hypothetically viewed as a result of

some sort of flotation.

Fig. 4. An apparent phase separation

in the heated crude oil, revealed by

optical absorption measurements.

Fig. 5. A common effect of the thermal

pre-treatment on pour points of petro-

leum fluids of various origin (cf. text).

The asphaltene aggregates may be carried to the oil surface by

low-density wax crystals. If the above results would be confirmed

by further studies, the obvious practical application may be an eco-

nomical process of de-asphalting of crudes.