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may be more closely related, than conventionally believed. Among
these models are “asphaltene crystallite” with some degree of or-
der,
49
more disordered “hairy tennis ball”
50
and “polymer struc-
ture”
51
, a liquid-like “glassy droplet”.
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Immediate Relevance to the Properties of
Native Petroleum
We are aware that some skeptical reservoir engineers may wonder:
“who needs these scientific speculations and nice pictures obtained
in laboratory exercises with artificially designed formulations;
most probably all this is just one more showoff in the fashionable
subject of “NANO” with little relevance to honest reservoir fluids?”
It is true that at the moment we can not make any suggestion
about the details of nanocolloid phases in “live” petroleum – this
will need much more complicated and costly experiments. How-
ever, a detailed inspection of available information on the proper-
ties of world’s “dead” (recovered) petroleum fluids show surpris-
ingly strong effects which may originate in the phase diagram of
asphaltene nanocolloids of Fig. 5. In particular, we have compiled a
database for several hundreds of recovered world’s crudes with
various asphaltene contents. Previously published analysis of this
database
53
did not take into account the newly obtained informa-
tion on asphaltene phase diagram, which now highlights some of
the previously overlooked features.
As an example, Fig.6 shows a log-log plot of viscosity vs as-
phaltene content for ca. 200 crudes of various geographi-
cal/geological origin. The solid line in Fig. 6 has no special signifi-
cance and is drawn just to emphasize the apparent viscosity ex-
trema.
For quantitative interpretation of underlying mechanisms, the
statistics has to be improved, especially in the range of low asphal-
tene contents; nevertheless even the “raw” data of Fig. 6 clearly
demonstrate a striking coincidence of sharp viscosity anomalies
with all (but one) phase boundaries of asphaltene nanocolloids in
Fig. 5.
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