As shown below, Wabasca
(top yellow line) has one of the lowest reservoir temperatures
(around 50 degrees F) and highest viscosities of all the comparable
North American heavy oil fields. As the temperature is increased to
boiling (the 100 degree C or 212 deg. F vertical line) or above in a
steam flood or SAGD operation the viscosity drops from 5 million to
less 1000 centipoise. At that temperature and above the bitumen oil
will flow like motor oil.
If a pipeline leaks or
breaks, the pressure and temperature will drop suddenly and the oil
will tend to revert to its natural “hockey puck” statei.
This graph also shows that Wabasca is more viscous at all equivalent
temperatures than for example Cold Lake (in purple) which is
reportedly the ultimate source of the oil spilled by Enbridge into
the Kalamazoo River in Michigan on July 2010.ii
Therefore, oil from Wabasca will always have a greater resistance to
flow than the Enbridge spill making the tar sands more difficult to
clean up on land. It also means that Exxon would require even more
diluent and chemicals to keep it flowing than other companies.
ii
Enbridge Energy 2011, Limited Partnership Line 6B Incident,
Marshall, Michigan
Conceptual
Site Model Prepared: November 30, 2010 Version 0
Source:
circleofblue.org
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