Нефтегазовые нанотехнологии для разработки и эксплуатации месторождений. Часть 2. Евдокимов И.Н - 15 стр.

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tems is a closed-loop phase boundary at T–C diagram.

28-30

An in-

spection of Fig. 5 shows that, indeed, phase boundaries 2 and 3

tend to be parts of such loop. Other characteristic boundaries of

closed-loop T–C diagrams are “upper” and “lower” “critical solution

temperatures” (UCST and LCST) which, apparently, also are pre-

sent in Fig. 5.

Fig. 5. A complex T–C phase diagram for association nanocolloids

of asphaltenes in petroleum media, constructed on the basis

of the (limited) currently available data.

“Former CMC” boundaries (lines 3a and 3b in Fig. 5).

“Specific points” at ~1–10 g/l are the most documented one, owing

to a large magnitude of abrupt changes in concentration dependen-

cies virtually of all measurable parameters.

More detailed inspec-

tion shows that published “CMC” data tend to concentrate at two

sub-ranges, namely at ~1–3 g/l and at ~7–10 g/l. As discussed

above, for many years, these specific points have been interpreted

by employing the concept of CMC, projected from surfactant sci-

ence. When it became clear that asphaltenes do not exhibit true

CMC behavior, a new abbreviation was introduced – CNAC (criti-