Tar sands
Tar sands are naturally occurring petroleum deposits where denser, viscous petroleum fractions occur in soil.[1][2]
Traditional petroleum deposits are found in domes of porous rock that is capped by layers of impervious rock. The weight of the overlying rock places these deposits under pressure, so when they are drilled into pressure forces the less viscous fractions to flow to the surface. Water, or more recently waste carbon dioxide, can be pumped underground to extend the productivity of deposits, to maintain enough pressure to force oil to the surface.
Tar sands are harder to exploit, because the bitumen they are largely composed of has to first be separated from the sand, and, without further processing, it is too viscous to flow in a pipeline. Additionally the separation of the sand from the bitumen produces large volumes fine, silty tailings. Due to the small size of the finer grains in the tailings, they take a very long time to settle, and require large, environmentally dangerous tailing ponds. Remaining petroleum fractions stuck to the tailings, and by-products of the separation process make the tailing, and the tailing ponds, toxic to wildlife.
The original techniques for separating the sand and bitumen consumed two or three barrels of fresh water for every barrel of petroleum produced.[3]
"Oil sands"
In recent decades petroleum industry spokesmen have tried to rename tar sands to the less accurate, but more pleasant sounding, oil sands.[4][5][6][7] The technical definition of "crude oil" is that it flows at room temperature.[1] Since the petroleum from tar sands are too dense to flow at room temperature it is not a kind of crude oil.
Location of deposits
The two largest tar sands deposits are in Canada and Venezuala. Both deposits have been described as the largest known petroleum deposits in the world, other than the deposits in the Persian Gulf.
Venezuala's tar sands are near the headwaters of the Orinoco River. Most of Canada's tar sand deposits lie in the watershed of the Athabasca River, a tributary of the Mackenzie River. There is also a large deposit on Melville Island in the high Arctic.
References
- ↑ 1.0 1.1 John Kemp (2012-10-15). "U.S. crude oil exports may be inevitable" (in English). London: Financial Post. Archived from the original on 2012-11-05. http://www.webcitation.org/query?url=http%3A%2F%2Fbusiness.financialpost.com%2F2012%2F10%2F15%2Fu-s-crude-oil-exports-may-be-inevitable%2F&date=2012-11-05.
- ↑ "Technology marches on — so does oil" (in English). OPEC. Archived from the original on 2012-11-06. http://www.webcitation.org/query?url=http%3A%2F%2Fwww.opec.org%2Fopec_web%2Fstatic_files_project%2Fmedia%2Fdownloads%2Fpublications%2FOB032007.pdf&date=2012-11-06.
- ↑ "Managing water" (in English). Shell oil. Archived from the original on 2012-11-05. http://www.webcitation.org/query?url=http%3A%2F%2Fwww.shell.com%2Fhome%2Fcontent%2Faboutshell%2Four_strategy%2Fmajor_projects_2%2Fathabasca%2Fwater%2F&date=2012-11-05. "At our Athabasca Oil Sands Project in Canada we use around two to three barrels of fresh water to extract one barrel of bitumen."
- ↑ David Suzuki (2011-02-03). "It will take more than rebranding to make tar sands oil "ethical"" (in English). Archived from the original on 2012-11-05. http://www.webcitation.org/query?url=http%3A%2F%2Fwww.davidsuzuki.org%2Fblogs%2Fscience-matters%2F2011%2F02%2Fit-will-take-more-than-rebranding-to-make-tar-sands-oil-ethical%2F%3Fgclid%3DCIrmoertuLMCFUZgMgodJHQAtg&date=2012-11-05.
- ↑ Andrew Nikiforuk (2010). "Tar Sands: Dirty Oil and the Future of a Continent" (in English). Greystone/David Suzuki Foundation. p. 14. ISBN 9781553655558. http://books.google.ca/books?id=3Z7wC7daVh4C&pg=PA147&lpg=PA147&dq=%22tar+sands%22+renamed+OR+renaming+OR+rename+%22oil+sands%22&source=bl&ots=MJXhmtD5ZW&sig=en05QvNccX_k30TH4LYcBiV3HMs&hl=en&sa=X&ei=JDuYULfgC5OByQHerYGQBg&ved=0CDsQ6AEwAzgK#v=onepage&q=%22tar%20sands%22%20renamed%20OR%20renaming%20OR%20rename%20%22oil%20sands%22&f=false. Retrieved 2012-11-05. "Rick George, president and CEO of Suncor, highlighted bitumen's thoroughly roguish nature in a 2008 speech to the World Heavy Oil Congress. Although he prefers the term oil sands, George unwittingly made a good argument for calling the stuff tar. Bitumen may contain hydrocarbon, he said, but you can't use it as a lubricant because "it contains minerals nearly as abrasive as diamonds." You can't pump it, because "it's as hard as a hockey puck in its natural state." It doesn't burn all that well, either; "countless forest fires over the millennia have failed to ignite it.""
- ↑ Jason Staeck (2012-02-14). "Oil Sands Semantics: I Say Potato, You Say Po-TarSands" (in English). Vantagewire. Archived from the original on 2012-11-05. http://www.webcitation.org/query?url=http%3A%2F%2Fwww.vantagewire.ca%2Farticles%2Fcommentary-oil-sands-semantics-i-say-potato-you-say-po-tarsands-47681&date=2012-11-05. Retrieved 2012-11-. "Based solely on the choice of a descriptor when talking about the retrieval of bitumen from the sands in the Athabasca basin in Alberta, it becomes obvious which side of the issue you take. Technically speaking the official term for this hydrocarbon source is “bituminous sands,” but we rarely see this used in any main stream media article. Perhaps it’s too cumbersome, or confusing, but it is the most accurate, as bitumen is indeed being extracted during the process."
- ↑ "What is the difference between oil sands and tar sands?" (in English). Experts123. Archived from the original on 2012-11-05. http://www.webcitation.org/query?url=http%3A%2F%2Fwww.experts123.com%2Fq%2Fwhat-is-the-difference-between-oil-sands-and-tar-sands.html&date=2012-11-05. "The difference is only the name. In the 1970s, the oil industry wanted to make the tar sands sound cleaner, so they created a campaign to rename them "oil sands" and focus on the fact that oil would be derived from them. more"
