TYPES OF OIL
No two types of petroleum are the same. Oils range from light crude, which flows easily, to heavy crudes to semisolid asphalt. They color of petroleum can a vary in color from black, green, brown or yellow to almost clear. The differences depend on materials from which the petroleum is made and the processes they undergo while underground.
Light, sweet crudes are generally the most desirable. They have less sulfur and other impurities are cheap and easy to refine. Heavy, sour crudes have more sulfur, which gives them their distinctive sour odor. They need conversion refineries to strip them of their sulfur. Heavy crudes yield large amounts of unwanted heavy, heating oil — as much as half of every barrel — and large amounts are needed to yield gasoline, diesel and jet fuel.
Brent crude from the North Sea is very light and sweet while some oils from Saudi Arabia and Russia are heavy and sour. By most estimates 70 to 80 percent of the world’s oil is heavy and sour.
Crude is classified as paraffin-based, mixed-base and asphalt-base, depending on the amounts of paraffin and asphalt present. Paraffin-based are the best quality.
Bitumen is an extra heavy, viscous oil that has to be treated before it can be used in refineries to produce gasoline and diesel. Bitumen is widely used as a sealant and a paving material. The word “mummy” is derived from the term for it in ancient Persian. With expensive energy-sucking technology it can be turned into synthetic crude. Production produces a lot of greenhouse gases.
Websites and Resources: American Petroleum Institute api.org ; Investopedia Oil Handbook investopedia.com/features/industryhandbook/oil_services.asp ; Petrostratgies Learning Institute petrostrategies.org/Learning_Center ; U.S. Energy Information Administration eia.doe.gov/petroleum ; New York Times article New York Times ; Wikipedia article Wikipedia ; Oil. com oil.com ; Petroleum Online petroleumonline.com ; Natural Gas.org naturalgas.org
Book: “The Prize” by Daniel Yergin.
Oil sands — a complex mix of sand, water and bitumen — look like dirt but smell like diesel fuel. Ninety percent of it is sand — a mixture of quartzite, clay and water. The remaining 10 percent — the “tar” or “oil” — a mixture of very heavy hydrocarbons known as bitumen. Bitumen is widely used as a sealant and a paving material. At room temperature pure bitumen is viscous it will not flow. The word “mummy” is derived from the term for it in ancient Persian. With expensive energy-sucking technology it can be turned into synthetic crude. [Source: Elizabeth Kolbert, The New Yorker, November 12, 2007]
The price of oil has to be above $60 a barrel for the mining of oil sands to be profitable. The cost of production can be as much $70 a barrel compared to a few dollars a barrel in some the largest inshore oil fields in the Middle East. For every barrel of synthetic crude that is produced 2,000 kilograms of tar sands has to be dug up and separated.
The first oil sands project began in 1967. In 1956, the American geologists Manely Natland proposed using atom bombs as “thermal devises” to create cavities and heat up the bitumen so it could be easily collected. In the mid 1960s, the Soviet Union conducted experiments using a half dozen nuclear explosions to stimulate conventional oil production. The technique did increase production but unfortunately the oil was radioactive.
There is a huge oil sands deposit in Alberta, Canada (See Below). Created by peat bogs and forest millions of years old, the deposits are believed to have been placed in their current position by the uplift of the Rocky Mountains 70 million years ago. There is another huge tar-sand-like deposit in eastern Venezuela called the Faja Petrolifera del Orinoco.
Oil Sands in Canada
Near Fort McMurray in Alberta, Canada — north of Edmonton — is a 15,000 square mile area rich in oil sands called Athabasca. The area is currently under intensive development. The oil sands area in Alberta stretch from east to west nearly from the border of Saskatchewan almost to British Columbia. There are three major deposits. Together they cover an area of about 57,000 square miles, the size of Florida.
There is estimated to be enough bitumen in Alberta to yield 174 billion barrels of synthetic crude, or about three fourths of the proven reserves of Saudi Arabia.. Even if only 10 percent of this recoverable it represents the second largest oil reserve in the world after Saudi Arabia’s, larger than the reserves of Kuwait, Norway and Russia put together.
Production at Athabasca reached 1.3 million barrels a day in 2008 and 2009. The plan is to increase that figure to 2.5 million a day in 2015 and 6 million by 2030. The process requires large amounts of natural gas to separate the oil from the sand. So much energy is needed there has been discussion of building a nuclear power plant at the site to generate electricity. Also under discussion is setting up a system to turn the oil from the sands into gas that can operate the factories. Much of the oil from transported to the United States, where it is upgraded, refined and largely used.
Private companies have estimated that the potential profit to be made by oil shale in Alberta exceed $100 billion. Shell, ConocoPhillips. Chevron and Imperial Oil which is primarily owned by ExxonMobil, all have stakes in Athabasca.
The brakes were put on the Canadian oil sands project when the price of crude fell in early 2009. More than $60 billion worth of projects were put on various degrees of hold. It was hoped output would double between 2007 and 2010 and triple by 2015.
Thanks in a large part to oil sands, Canada is now the No. 1 source of imported oil in the United States. In 2007, Alberta produced about 18 million barrels of crude oil a day from oil sands, 75 percent of which as exported to the United States.
Mining Oil Sands
The oil sands lie beneath Alberta’s muskeg peat bogs. They are extracted with steam injections or strip mined with house-size shovels and trucked in 400 ton loads in small-mansion-size trucks. The truck are outfit with heaters in their beds to keep oil from freezing to them in the winter. The sticky sands are fed through a series of giant washing machines that crush and cleans the sand with water and solvents, separating out the bitumen. The bitumen is then heated to 900 F in coker and distilled and processed with hydrogen gas and a catalyst, yielding low-sulfur crude oil at a cost between $10 and $20 a barrel.
Mining and processing oil sands is an environmentally unfriendly process that tears large swaths of sensitive landscape; yields large amounts of greenhouse gases; and sucks up large amounts of water from rivers. About two to five barrels of water is lost and two ton of rock and sand is processed to get one barrel of oil. Large swaths of forest have been cleared. Hills of sludgy tailings dot the landscape. Rivers that were once blue are now brown, The air is filled with dust and fumes.
Enough earth is moved at the Aurora North mine to fill a huge stadium every 48 hours. Soaring cost for labor, materials and energy needed to turn bitumen into useable fuel are very high and many argue that prose of oils needs to be above $50 a barrel to make it viable and $60 a barrel to sustain growth.
In easy-to-mine places the tar sands start at about a depth of 30 meters below the surface and continues down in a continuous layers for another 50 meters. Before mining can start everything on top of it’soil, trees, rocks, bushes, wildlife — has be to scraped off and carried away. The removed material is called overburden. Below the sands is layer of limestone, the remains of an ancient sea.
Describing the machine that digs up the earth, Ben Webster wrote in the Times of London: “A giant mechanical digger gouges out a chunk of the topsoil, grass and tree stumps, extending a neat furrow that stretches into the distance. Dozens of similar furrows run parallel with the regularity of a ploughed field.”
The tar sands are harvested with trucks that hold hundreds of tons. The largest truck — the Caterpillar 797B — can haul more than 400 tons. The tires on this truck are four meters high and the cab is seven meters off the ground. Elizabeth Kolbert wrote in The New Yorker that someone told her that driving one was “like trying to steer a house while peering out the window of the upstairs bathroom.” The trucks dump the material through a grate into a giant tank of hot water.
Processing Oil Sands
To get the 10 percent of bitumen the other 90 percent of material has to be separated out. This is largely done in a hot-water tank that spins the sand around, releasing the bitumen. The bitumen is made of molecules with more than 20 carbon atoms compared to five for liquid oil. In the upgrapder the large hydrocarbons are “cracked” down into smaller units at a temperature of nearly 900 degrees F and becomes synthetic crude which can be piped to refineries, where it is converted mostly into transportation fuels.
The production process produces huge tailings hills and tailing ponds with water too contaminated with mercury and other toxins to be released back into the environment. The main mining site contained nine such ponds in 2007, covering a total area of 11 square miles. Leakages from these ponds has been blamed for high cancer rates among people living down river from the ponds.
In the deep difficult-to mine areas in-situ extraction is used. In this process known as Steam Assisted Gravity Drainage (SagD) two horizontal wells are drill into the sand, one above the other. High-pressure stead is injected into the top well. When the tar sands reach a temperature of about 400 degrees the bitumen begins to flow into the bottom well, from which it can be extracted.
Needless to say the extraction of bitumen from oil sands is very energy intensive and expensive. For every three barrels of oil that is extracted one is needed for processing. The process of converting the sands to synthetic oil is around $30 a barrel. The process also generates lots of greenhouse gases, 15 percent to 40 percent more than is used processing conventional sources of petroleum.
Oil shale — containing a hydrocarbon compound called kerogen — is another potential petroleum source. It is similar to oil sands except the oil is locked in rock rather than sand. The U.S. government estimates there are 800 million barrels of recoverable oil shale in the United States, much of it in the 16,000-square-mile Green River formation in Colorado, Utah and Wyoming, which holds 2 trillion barrels of oil, double all the known reserves of oil from conventional sources.
The problem with oil shale is that no one has found an acceptable, profitable and environmentally acceptable way of extracting the oil. As one might guess extracting oil from rock is no easy endeavor. Most efforts have been too expensive and energy intensive to compete with conventional oil sources, plus mining it lays waste to vast expanses of the landscape, and threatens groundwater in places where water is scarce.
As is the case with oil sands, the kergen can be steamed out but the process is more difficult because it is extract from rock rather than sand. In the processing plant the kergen is converted into vapor and then distilled into crude. The total cost is $55 to $75 per barrel.
Extracting Oil from Oil Shale
Exxon launched a multi-billion dollar project in the 1970s but gave up because it was way too expensive. Shell is currently the leader in shale oil development. It has developed a technique for recovering oil from organic matter found in oil shale and has plans to place heaters underground and suck the kerogen out rather than mining it.
Shell hopes to profitably extract shale oil by drilling holes 2,000feet into the shale and use heaters to slowly cook the shale at temperatures of about 650 degrees F for two or three years. To protect groundwater it has proposed circulating refrigerants through pipes in the surrounding rock.
A small Texas-based company called EGL Resources has proposed running steam through a radiator system underneath the shale. A web of pipes would pump the liquid that cooks the oil out of the rock. To protect groundwater it plans to create perimeter wells to pump water out and plans to plug water channels with a grout of polymers.
Chevron plans to circulate carbon dioxide and other gases or fluids to create chemical reactions within fractured shale formations, forcing oil up. It hopes to use the shale formations themselves as walls and monitor groundwater like the two other companies. [Source: New York Times]
Synthetic oil can be created from coal. Coal is gasified into carbon monoxide and hydrogen, which is converted into a paraffin wax using the Fischer-Tropsch synthesis method. The molecules are refined to produce synthetic diesel at a cost of $40 to $50 per barrel. It is an inefficient process that releases lots of greenhouse gases.
The process of turning coal into liquid fuel was invented by German scientists Franz Fischer and Hans Tropsch in 1923. The Nazis used the technology to fuel their war machine, producing 125,000 barrel a day of synthetic fuel at 25 plants. South Africa uses the same process today. Expensive and environmentally-destructive, coal -derived synthetic fuels emit less sulfur and nitrogen than gasoline when it burned in a car but produce large amounts of carbon dioxide when it made from coal and when it is burned in a car. See Coal
Alternative oils may make up 35 percent of the world’s supply in 2015. One of the major drawbacks is that they produce a lot of pollution and greenhouse gas; eat up a lot of energy to produce; and leave behind a scared landscape and piles of tailings that will dwarf all other open pit and strip mines.
Text Sources: World Almanac, United States Geological Survey (USGS) Minerals Resources Program, Investopedia Industry Handbooks, U.S. Energy Information Administration, Department of Energy and National Geographic articles. Also the New York Times, Washington Post, Los Angeles Times, Smithsonian magazine, Natural History magazine, Discover magazine, Times of London, The New Yorker, Time, Newsweek, Reuters, AP, AFP, Lonely Planet Guides, Compton’s Encyclopedia and various books and other publications.
Last updated March 2011