In the past it was not unusual for oil fields to be discovered due to natural seeps. These fields were often easy to produce, even with primitive technology. This has not been the case with the Athabasca oil sands in Alberta, Canada. The first European to comment on the unusual substance was James Knight, Factor of Fort York, who noted the presence of “gum or pitch that flows out of the banks of a river” in his journal in 1715, according to oilsandstoday.com. The river in question was the Athabasca.
Two years later, Waupiso of the Cree people brought samples to the Hudson’s Bay Co. trading post at Fort Churchill, according to the Regional Aquatics Monitoring Program (RAMP) website. Several decades later, Peter Pond noted oil sands at the confluence of the Athabasca and Clearwater rivers, and in 1790 Sir Alexander Mackenzie described the oil sands in his exploration of the region.
As time went on, interest grew about this potential resource. Robert Bell joined a Geological Survey of Canada expedition and is credited with being the first to realize the potential of the area. He gave samples to G. Christian Hoffman, a chemist, who successfully separated the bitumen from the sands using water. But despite Bell’s conviction that the oil sands must be representative of large petroleum reservoirs, the 24 wells drilled between 1906 and 1917 were dry.
Still, efforts to separate the sand and oil continued, and World War I gave Canada the impetus to try harder to tap into this resource. The Alberta Research Council was formed to support oil sands research as well as other research. A researcher named Dr. Karl Clark perfected a method of using hot water to separate the bitumen, and a field-scale plant was built near Fort McMurray in 1924.
But it wasn’t until the 1950s that the technology was far enough along for commercial development. In 1953 the Great Canadian Oil Sands consortium, now Suncor, was formed. Plant construction began in 1964, and production started in 1967. The Alberta Energy website predicts production to reach 3.7 MMbbl/d of oil by 2020.
Geology and exploitation
According to the RAMP website, the Athabasca oil sands deposit, which is the third largest oil sands deposit in the world, is the largest Cretaceous oil sands deposit in Alberta, with an areal extent of about 46,000 sq km (17,760 sq miles). The McMurray Formation, which is up to 45.7 m (150 ft) thick, is a layer of shale, sandstone and oil-filled sands and contains the bulk of the deposits. It is exposed at the surface near the Athabasca River but is several hundred meters below the surface in other parts of the play.
This has led to two distinct extraction methods—mining and in situ production. The shallower deposits are mined, which has been a concern to environmentalists and has stalled the Keystone XL pipeline project for years. To begin a mining operation, the overburden of muskeg, sand, gravel and clay is stored for later reclamation. The sand is then mined and taken to crushers.
Here the mixture is crushed, fi ltered and mixed with hot water and then transported to an extraction plant.
The extraction plant forces the sand and water to settle in the bottom while the bitumen bubbles to the top. Once separation is complete, the bitumen goes through primary upgrading, while the sand and water are moved to a tailings pond. These sites can eventually be reclaimed, though the process takes several years. While mining gets most of the negative press, it actually
accounts for only 20% of oil sands production.
The primary form of in situ production in the Athabasca region is steam-assisted gravity drainage (SAGD). This involves the drilling of a pair of horizontal wells, one drilled directly beneath the other. The top well injects steam to heat the reservoir. This creates a steam chamber to lower the bitumen’s viscosity.
Several projects are underway to continue to develop this resource. The Athabasca Oil Sands Project, a joint venture between Shell Canada Ltd., Chevron Canada Ltd. and Western Oil Sands LP, has a production capacity of 255,000 bbl/d of synthetic crude, according to Shell’s website. The company has approval to expand this by up to 215,000 bbl/d.
The project is unique in that it is implementing the world’s fi rst commercial-scale carbon-capture and storage project for an oil sands operation. The Quest project will reduce CO2 emissions from Shell’s oil sands operations by more than 1 MM tonnes/year by capturing CO2 from its Scotford upgrader and permanently storing it underground.
Other efforts to minimize the environmental footprint also are underway, and the Alberta provincial government is an active participant in many of these projects. A consortium called Canada’s Oil Sands Innovation Alliance has brought together companies active in oil sands exploitation, and its website notes that its member companies have shared 777 technologies that
cost more than $950 million to develop.
Its ongoing projects are examining such disparate technologies as centrifuges for the fi ne tailings that don’t settle to the bottom of the tailings pond, managing the use of freshwater in oil sands operations, topsoil reconstruction, recovering waste heat for reuse and even a “flying drilling rig” that allows rig equipment to be flown to remote locations without disturbing the forest.
The last was a collaboration between Cenovus, HyTech Drilling Ltd. and other contractors. The product is called the SkyStrat Drilling Rig. It eliminates the need for temporary roads and has the potential to reduce water usage.
In another collaboration, Imperial Oil and BP are spearheading a project known as the Boiler Blowdown Reduction Technology project. This project aims to reduce the amount of water that must be disposed of in steam generation for SAGD projects. And Faster Forests has been created by ConocoPhillips Canada, Husky Energy, MEG Energy, Nexen, Shell Canada, Statoil Canada and Suncor Energy based on studies from the University of Alberta to accelerate land reclamation after operations have ceased. To date, the program has resulted in almost 3 million trees and shrubs being planted.
Efforts like these can help quiet the critics and continue to provide Canada with a sustainable energy future.
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