Нефтегазовые нанотехнологии для разработки и эксплуатации месторождений. Часть 2. Евдокимов И.Н - 11 стр.

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action–limited processes into larger and larger aggregates until

these loose buoyancy and precipitate out of the liquid. Evidently, in

these essentially continuous schemes there are no complex phase

diagrams of hard sphere colloids, the only “critical boundary” being

not a specific phase transformation, but a precipitation onset.

Just one additional “critical boundary” appears in colloidal

models where colloidal particles are not permanently present in

petroleum but are formed from molecular solutions of asphaltenes

at certain critical conditions as a result of some association proc-

esses which, for a long period of time, were regarded to be similar

to micellization phenomena of simple surfactants. “Critical micelli-

zation concentration” (“CMC”) of asphaltenes has been the subject

of numerous publications,

though now it is realized that some

processes other than textbook “micellization” should be responsible

for this particular structural transformation of asphaltene

(nano)colloids.

Fig. 3. A complex T-C phase diagram for association colloids in a binary

surfactant/water system. Dashed critical boundaries are those for conventional

“micellization” (CMC) and for solid precipitation (SP) (adapted from Refs. 26,27).

Apparently, it never has been realized that the assumption of

“micellization” places asphaltenes into a principally different class

of disperse systems. A system of solid particles dispersed in a liq-