TORONTO: US refineries are processing record quantities of heavy crude from Canada as the perfect complement to light oils from North Dakota and Texas as they struggle to keep their average blend steady.
Crudes vary enormously – from low-density oils with few impurities to much denser oils containing a relatively high percentage of sulphur and heavy metals such as nickel and vanadium.
The density of crudes is normally expressed in terms of degrees API, which compares oil to the density of water at a standard temperature of 60 degrees Fahrenheit.
Crude density ranges from 42 degrees API for Bakken (which makes it about 80 percent as dense as water at standard temperature) to 27 degrees for Arab Heavy (89 percent as dense as water) and 22 degrees for Western Canadian Select (93 percent as dense as water).
But the big differences are easier to understand by switching to more familiar units. A cubic metre of Bakken crude weighs around 815 kg, compared with 885 kg for Arab Heavy and 925 kg for Western Canadian Select.
