Oil sands
Oil sands are a type of unconventional petroleum deposit. They are either loose sands, or partially consolidated sandstone containing a naturally occurring mixture of sand, clay, and water, soaked with bitumen.
Significant bitumen deposits are reported in Canada, Kazakhstan, Russia, and Venezuela. The estimated worldwide deposits of oil are more than. Proven reserves of bitumen contain approximately 100 billion barrels, and total natural bitumen reserves are estimated at worldwide, of which, or 70.8%, are in Alberta, Canada.
Crude bitumen is a thick, sticky form of crude oil, and is so viscous that it will not flow unless heated or diluted with lighter hydrocarbons such as light crude oil or natural-gas condensate. At room temperature, it is much like cold molasses. The Orinoco Belt in Venezuela is sometimes described as oil sands, but these deposits are non-bituminous, falling instead into the category of heavy or extra-heavy oil due to their lower viscosity. Natural bitumen and extra-heavy oil differ in the degree by which they have been degraded from the original conventional oils by bacteria.
The 1973 and 1979 oil price increases, and the development of improved extraction technology enabled profitable extraction and processing of the oil sands. Together with other so-called unconventional oil extraction practices, oil sands are implicated in the unburnable carbon debate but also contribute to energy security and counteract the international price cartel OPEC. According to the Oil Climate Index, carbon emissions from oil-sand crude are 31% higher than from conventional oil. In Canada, oil sands production in general, and in-situ extraction, in particular, are the largest contributors to the increase in the nation's greenhouse gas emissions from 2005 to 2017, according to Natural Resources Canada.
History
The use of bituminous deposits and seeps dates back to Paleolithic times. The earliest known use of bitumen was by Neanderthals, some 40,000 years ago. Bitumen has been found adhering to stone tools used by Neanderthals at sites in Syria. After the arrival of Homo sapiens, humans used bitumen for construction of buildings and waterproofing of reed boats, among other uses. In ancient Egypt, the use of bitumen was important in preparing mummies.In ancient times, bitumen was primarily a Mesopotamian commodity used by the Sumerians and Babylonians, although it was also found in the Levant and Persia. The area along the Tigris and Euphrates rivers was littered with hundreds of pure bitumen seepages. The Mesopotamians used the bitumen for waterproofing boats and buildings. In Europe, they were extensively mined near the French city of Pechelbronn, where the vapour separation process was in use in 1742.
In Canada, the First Nation peoples had used bitumen from seeps along the Athabasca and Clearwater Rivers to waterproof their birch bark canoes from early prehistoric times. The Canadian oil sands first became known to Europeans in 1719 when a Cree person named Wa-Pa-Su brought a sample to Hudson's Bay Company fur trader Henry Kelsey, who commented on it in his journals. Fur trader Peter Pond paddled down the Clearwater River to Athabasca in 1778, saw the deposits and wrote of "springs of bitumen that flow along the ground". In 1787, fur trader and explorer Alexander MacKenzie on his way to the Arctic Ocean saw the Athabasca oil sands, and commented, "At about 24 miles from the fork are some bituminous fountains into which a pole of 20 feet long may be inserted without the least resistance."
Cost of oil sands petroleum-mining operations
In their May 2019 comparison of the "cost of supply curve update" in which the Norway-based Rystad Energy—an "independent energy research and consultancy"—ranked the "worlds total recoverable liquid resources by their breakeven price", Rystad reported that the average breakeven price for oil from the oil sands was US$83 in 2019, making it the most expensive to produce, compared to all other "significant oil producing regions" in the world. The International Energy Agency made similar comparisons.The price per barrel of heavier, sour crude oils lacking in tidewater access—such as Western Canadian Select from the Athabaska oil sands, are priced at a differential to the lighter, sweeter oil—such as West Texas Intermediate. The price is based on its grade—determined by factors such as its specific gravity or API and its sulfur content—and its location—for example, its proximity to tidewater and/or refineries.
Because the cost of production is so much higher at oil sands petroleum-mining operations, the breakeven point is much higher than for sweeter lighter oils like that produced by Saudi Arabia, Iran, Iraq, and the United States. Oil sands productions expand and prosper as the global price of oil increased to peak highs because of the Arab oil embargo of 1973, the 1979 Iranian Revolution, the 1990 Persian Gulf crisis and war, the 11 September 2001 attacks, and the 2003 invasion of Iraq. The boom periods were followed by the bust, as the global price of oil dropped during the 1980s and again in the 1990s, during a period of global recessions, and again in 2003.
Nomenclature
The name tar sands was applied to bituminous sands in the late 19th and early 20th century. People who saw the bituminous sands during this period were familiar with the large amounts of tar residue produced in urban areas as a by-product of the manufacture of coal gas for urban heating and lighting. The word "tar" to describe these natural bitumen deposits is really a misnomer, since, chemically speaking, tar is a human-made substance produced by the destructive distillation of organic material, usually coal.Since then, coal gas has almost completely been replaced by natural gas as a fuel, and coal tar as a material for paving roads has been replaced by the petroleum product asphalt. Naturally occurring bitumen is chemically more similar to asphalt than to coal tar, and the term oil sands is more commonly used by industry in the producing areas than tar sands because synthetic oil is manufactured from the bitumen, and due to the feeling that the terminology of tar sands is less politically acceptable to the public. Oil sands are now an alternative to conventional crude oil.
Geology
The world's largest deposits of oil sands are in Venezuela and Canada. The geology of the deposits in the two countries is generally rather similar. They are vast heavy oil, extra-heavy oil, and/or bitumen deposits with oil heavier than 20°API, found largely in unconsolidated sandstones with similar properties. "Unconsolidated" in this context means that the sands have high porosity, no significant cohesion, and a tensile strength close to zero. The sands are saturated with oil which has prevented them from consolidating into hard sandstone.Size of resources
The magnitude of the resources in the two countries is on the order of 3.5 to 4 trillion barrels of original oil in place. Oil in place is not necessarily oil reserves, and the amount that can be produced depends on technological evolution. Rapid technological developments in Canada in the 1985–2000 period resulted in techniques such as steam-assisted gravity drainage that can recover a much greater percentage of the OOIP than conventional methods. The Alberta government estimates that with current technology, 10% of its bitumen and heavy oil can be recovered, which would give it about 200 billion barrels of recoverable oil reserves. Venezuela estimates its recoverable oil at 267 billion barrels. This places Canada and Venezuela in the same league as Saudi Arabia, having the three largest oil reserves in the world.Major deposits
There are numerous deposits of oil sands in the world, but the biggest and most important are in Canada and Venezuela, with lesser deposits in Kazakhstan and Russia. The total volume of non-conventional oil in the oil sands of these countries exceeds the reserves of conventional oil in all other countries combined. Vast deposits of bitumenover 350 billion cubic metres of oil in placeexist in the Canadian provinces of Alberta and Saskatchewan. If 30% of this oil could be extracted, it could supply the entire needs of North America for over 100 years at 2002 consumption levels. These deposits represent plentiful oil, but not cheap oil. They require advanced technology to extract the oil and transport it to oil refineries.Canada
The oil sands of the Western Canadian Sedimentary Basin are a result of the formation of the Canadian Rocky Mountains by the Pacific Plate overthrusting the North American Plate as it pushed in from the west, carrying the formerly large island chains which now compose most of British Columbia. The collision compressed the Alberta plains and raised the Rockies above the plains, forming mountain ranges. This mountain building process buried the sedimentary rock layers which underlie most of Alberta to a great depth, creating high subsurface temperatures, and producing a giant pressure cooker effect that converted the kerogen in the deeply buried organic-rich shales to light oil and natural gas. These source rocks were similar to the American so-called oil shales, except the latter have never been buried deep enough to convert the kerogen in them into liquid oil.This overthrusting also tilted the pre-Cretaceous sedimentary rock formations underlying most of the sub-surface of Alberta, depressing the rock formations in southwest Alberta up to deep near the Rockies, but to zero depth in the northeast, where they pinched out against the igneous rocks of the Canadian Shield, which outcrop on the surface. This tilting is not apparent on the surface because the resulting trench has been filled in by eroded material from the mountains. The light oil migrated up-dip through hydro-dynamic transport from the Rockies in the southwest toward the Canadian Shield in the northeast following a complex pre-Cretaceous unconformity that exists in the formations under Alberta. The total distance of oil migration southwest to northeast was about. At the shallow depths of sedimentary formations in the northeast, massive microbial biodegradation as the oil approached the surface caused the oil to become highly viscous and immobile. Almost all of the remaining oil is found in the far north of Alberta, in Middle Cretaceous sand-silt-shale deposits overlain by thick shales, although large amounts of heavy oil lighter than bitumen are found in the Heavy Oil Belt along the Alberta-Saskatchewan border, extending into Saskatchewan and approaching the Montana border. Note that, although adjacent to Alberta, Saskatchewan has no massive deposits of bitumen, only large reservoirs of heavy oil >10°API.
Most of the Canadian oil sands are in three major deposits in northern Alberta. They are the Athabasca-Wabiskaw oil sands of north northeastern Alberta, the Cold Lake deposits of east northeastern Alberta, and the Peace River deposits of northwestern Alberta. Between them, they cover over —an area larger than England—and contain approximately of crude bitumen in them. About 10% of the oil in place, or, is estimated by the government of Alberta to be recoverable at current prices, using current technology, which amounts to 97% of Canadian oil reserves and 75% of total North American petroleum reserves. Although the Athabasca deposit is the only one in the world which has areas shallow enough to mine from the surface, all three Alberta areas are suitable for production using in-situ methods, such as cyclic steam stimulation and steam-assisted gravity drainage.
The largest Canadian oil sands deposit, the Athabasca oil sands is in the McMurray Formation, centered on the city of Fort McMurray, Alberta. It outcrops on the surface about north of Fort McMurray, where enormous oil sands mines have been established, but is deep southeast of Fort McMurray. Only 3% of the oil sands area containing about 20% of the recoverable oil can be produced by surface mining, so the remaining 80% will have to be produced using in-situ wells. The other Canadian deposits are between deep and will require in-situ production.