Monday, March 31, 2014

Steam Flood (SAGD)

Steam Flood (SAGD), the Wabasca Field area thermal recovery process works on the same simple principle as when your mother accidentally steam-ironed your clothes the time you left chocolate in your pocket. The bitumen (“chocolate”) melts and drips down into the production pipe below (“runs down your pants”.) This high pressured, in situ, thermal process may be at least partially responsible for the uncontrolled bitumen blow-out at Cold Lake which contaminated over 150 acres of water and forced the drainage of a polluted lake. This seemingly unstoppable 2013 Tar Sands leak in six months has exceeded 300,000 gals and “has probably contaminated groundwater” according to Alberta Environment officialsi. Another tar sands pollution event could occur again at any time from these very shallow, artificially pressurized, reservoirs due to a fracking-like process that is virtually unregulated.

 Figure 7 SAGD- Steam Assisted Gravity Drainage Production


All of these enhanced production methods are important because as they act on the bitumen to make it more mobile, they also begin to change the chemistry of the oil. The hot steam not only melts the bitumen, it brings it into contact with large amounts of water which releases acids and other toxic chemicals into the oil. Unfortunately, the chemistry of the Tar Sands is so complex (especially after combining with diluent) that few of these toxic chemicals (polymers, solvents and surfactants) are even recognized after a spill unless they are looked for specifically with the latest detection equipment. This is no consolation to residents like those near the Mayflower and Kalamazoo spills, who are often assured that the area is safe to occupy by people who don’t actually know what chemicals the tar sands oil contain. In many cases, first responders do not even know what chemicals they are actually dealing with which puts them at even greater risk than they normally are when responding to conventional oil spills.

i Pratt, Sheila, Edmonton Journal October 23, 2013
CNRL bitumen leak has likely contaminated groundwater, report says

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