|
|
|
|
Non-conventional oil
|
| |
|
| |
Non-conventional oil is oil produced or extracted using techniques other than the traditional oil well method. Currently, non-conventional oil production is less efficient and some types have a larger environmental impact relative to conventional oil production. Non-conventional types of production include: tar sands, heavy oil, oil shale, biofuels, thermal depolymerization (TDP) of organic matter, and the conversion of coal or natural gas to liquid hydrocarbons through processes such as Fischer-Tropsch synthesis.
Discussion
Ask a question about 'Non-conventional oil' Start a new discussion about 'Non-conventional oil' Answer questions from other users |
Encyclopedia
Non-conventional oil is oil produced or extracted using techniques other than the traditional oil well method. Currently, non-conventional oil production is less efficient and some types have a larger environmental impact relative to conventional oil production. Non-conventional types of production include: tar sands, heavy oil, oil shale, biofuels, thermal depolymerization (TDP) of organic matter, and the conversion of coal or natural gas to liquid hydrocarbons through processes such as Fischer-Tropsch synthesis. These non-conventional sources of oil may be increasingly relied upon as petro motor fuel for transportation when conventional oil becomes "economically non-viable" due to depletion. Conventional sources of oil are currently preferred because they provide a much higher ratio of extracted energy over energy used in extraction and refining processes. Technology, such as using steam injection in tar sands deposits, is being developed to increase the efficiency of non-conventional oil production.
Extra heavy oil and tar sands
Extra heavy oils are extremely viscous, with a consistency ranging from that of heavy molasses to a solid at room temperature. Heavy crude oils have a density (specific gravity) approaching or even exceeding that of water. As a result, they cannot be produced, transported, and refined by conventional methods. Heavy crude oils usually contain high concentrations of sulfur and several metals, particularly nickel and vanadium. These properties make them difficult to pump out of the ground or through a pipeline and interfere with refining. These properties also present serious environmental challenges to the growth of heavy oil production and use. Venezuela's Orinoco heavy oil belt is the best known example of this kind of unconventional reserve. Estimated reserves: .
Heavy oils and tar sands (aka oil sands) occur world-wide, but the two most important deposits are the Athabasca Tar Sands in Alberta, Canada and the Orinoco extra heavy oil deposit in Venezuela. The hydrocarbon content of these deposits is called bitumen, on which the fuel Orimulsion is based. The Venezuelan extra heavy oil deposits differs from tar sands in that they flow more readily at ambient temperature and could be produced by cold-flow techniques, but the recovery rates would be less than the Canadian techniques (about 8% versus up to 90% for surface mining and 60% for steam assisted gravity drainage).
It is estimated by oil companies that the Athabasca and Orinoco sites (both of similar size) have as much as two-thirds of total global oil deposits. However, they have only recently been considered proven reserves of oil as cost to extract the oil declined to less than $15 per barrel at the Suncor and Syncrude mines while world oil prices rose to over $140 during the oil price increases since 2003.
Extracting a significant percentage of world oil production from these fossil fuels will be difficult since the extraction process takes a great deal of capital, manpower and land. Another major constraint is energy for heat and electricity generation, currently coming from natural gas, itself in short supply. A bitumen upgrader is under construction at Fort McMurray, Alberta to supply syngas to replace natural gas, and there are even proposals to build nuclear reactors using fuel from nearby Uranium City, Saskatchewan to supply steam and electricity.
At rate of production projected for 2015, about , the Athabasca oil sands reserves would last over 400 years. The oil extraction process requires either strip mining or in-situ processing, steam and caustic soda (NaOH). The process is more energy intensive than conventional oil and thus more expensive.
Tight Sands
"Natural gas from tight sands is conventional natural gas extracted from unconventional reservoirs." Tight sands are characterized by their low permeability because of compaction, the nature of the fine sediments, or pore space infilling. The flow rates of tight sands are uneconomical and it takes special technologies to produce this unconventional resource. New research processes and help from the US Department of Energy have enhanced the advances in technology used to retrieve and develop unconventional gas.
Keeping up with demand of oil and gas is very difficult, and companies are now embracing alternative methods of oil and gas production, such as unconventional resources. The actual definition of unconventional resources is "natural gas resources which require greater than industry-standard levels of technology or investment to harvest" As little as 10-12 years ago, unconventional resources were overlooked by natural gas companies. This is now a very important resource for natural gas companies today.
Oil shale
Oil shale is a general term applied to a group of fine black to dark brown shales rich enough in organic material (called kerogen) to yield petroleum and combustible gas upon distillation. The kerogen in oil shale can be converted to oil through the chemical process of pyrolysis. During pyrolysis the oil shale is heated to 450–500 °C in the absence of air and the kerogen is converted to oil and separated out, a process called "retorting". Oil shale has also been burnt directly as a low-grade fuel. Oil Shale requires extensive processing, consumes large amounts of water and energy. An operation producing requires approximately 1.2 gigawatts of dedicated electric generating capacity to heat the oil shale.
The United States Office of Naval Petroleum and Oil Shale Reserves estimates the world supply of oil shale at 1662 billion barrels (264 billion m³) of which 1200 billion barrels (191 billion m³) is in the United States.
US deposits
Most of the U.S. oil shale deposits are located in the Green River Formation (Green River and Washakie basins, Wyoming; Uinta basin, Utah; Piceance Creek basin, Colorado). Estonia, Russia, Brazil, Australia and China currently mine oil shale, however production is declining due to economic and environmental factors.
If oil shale could be used to meet a quarter of the current demand, of recoverable resources would last for more than 400 years.
However, attempts to develop these reserves have been going on for over 100 years with limited success.
Biofuels
Biofuels such as biodiesel, ethanol, and straight vegetable oil are also hydrocarbon fuels. There are non-hydrocarbon biofuels as well such as anaerobic hydrogen producers.
Thermal depolymerization
Thermal depolymerization (TDP) has the potential to recover a lot of energy from existing sources of waste such as petroleum coke as well as pre-existing waste deposits. Because energy output varies greatly based on feedstock, it is difficult to estimate potential energy production.
Coal and gas conversion
The conversion of coal and natural gas has the potential to yield great quantities of non-conventional oil albeit at much lower net energy output. Because of the high cost of transporting natural gas, many known but remote fields are not being developed. Conversion can make this energy available even under present market conditions.
The Karrick process is a low temperature carbonization (LTC) of coal, shale, lignite or any carbonaceous materials. These are heated at 360 °C to 750 °C (680 °F to 1380 °F) in the absence of air to distill out oil and gas. Production works out at about $35 per barrel.
The Fischer-Tropsch process operates on similar principle to the Karrick process, but is less efficient for coal gasification because more of the energy content of the coal is lost. For producing liquid fuel from natural gas, the Fischer-Tropsch process is currently an area of significant process research by most major oil companies.
See also
External links
- Chart representation of non-conventional components production profile until 2500 AD.
-
|
| |
|
|
