This is part of our series on the Alberta oil sands.
This week our own Robert Johnson is headed north to investigate one of the most controversial energy projects in the world: the Canadian oil sands.
Although he’ll be returning with a wealth of original insight and photographs (see his coverage of North Dakota’s oil boom), we’ve put together a basic primer on the oil sands.
What are oil sands?
Oil sands are a naturally occurring mixture of sand, clay, water and bitumen.
Bitumen is a heavy, viscous oil that is solid at 50 degrees Fahrenheit and acts like cold molasses at room temperature.
Layers of oil sand sit hundreds of feet beneath the soil, which, in some cases, must be stripped away in order to reach the deposits.
Photo: Alberta Geological Survey
Where are oil sands found?
Oil sands can be found in many places around the world, but the largest deposits are in Venezuela and Alberta, Canada.
There are 175 billion barrels of proven oil reserves in Canada, second only to Saudi Arabia and Venezuela. Of that number, 170 billion barrels come from Alberta’s oil sands, which are found in three main deposits: Athabasca, Peace River and Cold Lake.
Fort McMurray, where Robert will be visiting, lies in the Athabasca region.
Although a fistful of oil sand contains just 10 to 15 per cent bitumen, new technology in the past decade has transformed Alberta’s oil sands into a large-scale commercial industry.
How is oil extracted from oil sands?
Unlike oil pumped from conventional wells, oil sands must be mined or recovered using drilling methods and then treated to extract the bitumen before it can be refined into petroleum products like gasoline.
Tar sands near the surface — like in Fort McMurray— can be dug up using monster trucks and hydraulic shovels.
After mining, the tar sands are taken to an extraction plant where hot water separates the bitumen from the sand. The bitumen floats to the top of a separation cell, where it is skimmed off and sent to an upgrading facility that converts the material to crude oil. Sand, water, and bitumen residues are piped into tailing ponds where the water is recycled and reused in the mines. 20 per cent of Canada’s oil reserves are recovered by mining.
Oil sands that are deeper underground — more than 200 feet — are recovered using drilling (in situ) methods. The most common drilling method is steam injection, which pumps steam down a pipe into the reservoirs. The steam heats the oil rich-bitumen and allows it to be pumped to the surface. The bitumen is then sent to an upgrader where it is converted to synthetic crude oil.
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