Oil shale
Encyclopedia
Oil shale, an organic-rich fine-grained sedimentary rock
, contains significant amounts of kerogen
(a solid mixture of organic chemical compound
s) from which liquid hydrocarbon
s called shale oil
(not to be confused with tight oil
—crude oil
occurring naturally in shales) can be produced. Shale oil is a substitute for conventional crude oil; however, extracting shale oil from oil shale is more costly than the production of conventional crude oil both financially and in terms of its environmental impact.
Deposits
of oil shale occur around the world, including major deposits in the United States of America. Estimates of global deposits range from 2.8 Toilbbl of recoverable oil.
Heating oil shale to a sufficiently high temperature causes the chemical process of pyrolysis
to yield
a vapor
. Upon cooling the vapor, the liquid shale oil
—an unconventional oil—is separated from combustible
oil-shale gas
(the term shale gas
can also refer to gas occurring naturally in shales). Oil shale can also be burnt
directly in furnaces as a low-grade fuel for power generation
and district heating
or used as a raw material in chemical and construction-materials processing.
Oil shale gains attention as a potential abundant source of oil whenever the price of crude oil rises. At the same time, oil-shale mining and processing raise a number of environmental concerns, such as land use
, waste disposal
, water use
, waste-water management
, greenhouse-gas emissions and air pollution
. Estonia
and China have well-established oil shale industries, and Brazil
, Germany, Israel
and Russia also utilize oil shale.
Oil shales differ from oil-bearing shales, shale deposits which contain petroleum (tight oil
) that is sometimes produced from drilled wells. Examples of oil-bearing shales are the Bakken Formation
, Pierre Shale
, Niobrara Formation
, and Eagle Ford Formation
.
Oil shale, an organic-rich sedimentary rock, belongs to the group of sapropel
fuel
s.
It does not have a definite geological definition nor a specific chemical formula, and its seams do not always have discrete boundaries. Oil shales vary considerably in their mineral content, chemical composition, age, type of kerogen, and depositional history and not all oil shales would necessarily be classified as shale
s in the strict sense. Oil shale differs from bitumen-impregnated rocks
(oil sands and petroleum reservoir rocks), humic
coals and carbonaceous
shale
. While oil sands originate from the biodegradation
of oil, heat and pressure have not (yet) transformed the kerogen in oil shale into petroleum.
Oil shale contains a lower percentage of organic matter than coal. In commercial grades of oil shale the ratio of organic matter to mineral matter lies approximately between 0.75:5 and 1.5:5. At the same time, the organic matter in oil shale has an atomic ratio of hydrogen to carbon (H/C) approximately 1.2 to 1.8 times lower than for crude oil and about 1.5 to 3 times higher than for coals. The organic components of oil shale derive from a variety of organisms, such as the remains of algae
, spore
s, pollen
, plant cuticle
s and corky fragments of herbaceous
and woody plants, and cellular debris from other aquatic and land plants.
Some deposits contain significant fossil
s; Germany's Messel Pit
has the status of a Unesco World Heritage Site. The mineral matter in oil shale includes various fine-grained silicate
s and carbonates
.
Geologists can classify oil shales on the basis of their composition as carbonate
-rich shales, siliceous shales, or cannel
shales.
Another classification, known as the van Krevelen diagram, assigns kerogen types, depending on the hydrogen
, carbon
, and oxygen
content of oil shales' original organic matter. The most commonly used classification of oil shales, developed between 1987 and 1991 by Adrian C. Hutton of the University of Wollongong
, adapts petrographic
terms from coal terminology. This classification designates oil shales as terrestrial, lacustrine
(lake-bottom-deposited), or marine
(ocean bottom-deposited), based on the environment of the initial biomass
deposit. Hutton's classification scheme has proven useful in estimating the yield and composition of the extracted oil.
As with all oil and gas resources, analysts distinguish between oil shale resources and oil shale reserves. "Resources" refers to all oil shale deposits, while "reserves", represents those deposits from which producers can extract oil shale economically using existing technology. Since extraction technologies develop continuously, planners can only estimate the amount of recoverable kerogen.
Although resources of oil shale occur in many countries, only 33 countries possess known deposits of possible economic value.
Well-explored deposits, potentially classifiable as reserves, include the Green River
deposits in the western United States, the Tertiary deposits in Queensland
, Australia, deposits in Sweden
and Estonia
, the El-Lajjun deposit in Jordan
, and deposits in France, Germany, Brazil
, China, southern Mongolia
and Russia. These deposits have given rise to expectations of yielding at least 40 liters of shale oil per tonne of oil shale, using the Fischer Assay
.
A 2005 estimate set the total world resources of oil shale at 411 gigatons — enough to yield 2.8 Toilbbl of shale oil. This exceeds the world's proven conventional oil reserves
, estimated at 1.317 Toilbbl, as of 1 January 2007. The largest deposits in the world occur in the United States in the Green River Formation
, which covers portions of Colorado
, Utah
, and Wyoming
; about 70% of this resource lies on land owned or managed by the United States federal government.
Deposits in the United States constitute 62% of world resources; together, the United States, Russia and Brazil account for 86% of the world's resources in terms of shale-oil content. These figures remain tentative, with exploration or analysis of several deposits still outstanding. Professor Alan R. Carroll of University of Wisconsin–Madison
regards the Upper Permian lacustrine oil-shale deposits of northwest China, absent from previous global oil shale assessments, as comparable in size to the Green River Formation.
Britons
of the Iron Age
also used to polish it and form it into ornaments.
Modern industrial mining of oil shale began in 1837 in Autun
, France, followed by exploitation in Scotland, Germany, and several other countries.
Operations during the 19th century focused on the production of kerosene
, lamp oil, and paraffin
; these products helped supply the growing demand for lighting that arose during the Industrial Revolution
. Fuel oil, lubricating oil and grease, and ammonium sulfate
were also produced.
The European oil-shale industry expanded immediately before World War I
due to limited access to conventional petroleum resources and to the mass production of automobiles and trucks, which accompanied an increase in gasoline consumption.
Although the Estonian and Chinese oil-shale industries continued to grow after World War II
, most other countries abandoned their projects due to high processing costs and the availability of cheaper petroleum.
Following the 1973 oil crisis
, world production of oil shale reached a peak of 46 million tonnes in 1980 before falling to about 16 million tonnes in 2000, due to competition from cheap conventional petroleum in the 1980s
.
On 2 May 1982, known in some circles as "Black Sunday", Exxon
canceled its US$5 billion Colony Shale Oil Project
near Parachute, Colorado
because of low oil-prices and increased expenses, laying off more than 2,000 workers and leaving a trail of home-foreclosures and small-business bankruptcies.
In 1986, President Ronald Reagan
signed into law the Consolidated Omnibus Budget Reconciliation Act of 1985
which among other things abolished the United States' Synthetic Liquid Fuels Program
.
The global oil-shale industry began to revive at the beginning of the 21st century. In 2003, an oil-shale development program restarted in the United States. Authorities introduced a commercial leasing program permitting the extraction of oil shale and oil sands on federal lands in 2005, in accordance with the Energy Policy Act of 2005
.
, industry uses oil shale in Brazil
, China
, Estonia
and to some extent in Germany
, Israel, and Russia
. Several additional countries started assessing their reserves or had built experimental production plants, while others had phased out their oil shale industry. Oil shale serves for oil production in Estonia, Brazil, and China; for power generation in Estonia, China, Israel, and Germany; for cement production in Estonia, Germany, and China; and for use in chemical industries in China, Estonia, and Russia.
, 80% of oil shale used globally is extracted in Estonia.
Romania
and Russia have in the past run power plant
s fired by oil shale, but have shut them down or switched to other fuel sources such as natural gas
. Jordan
and Egypt
plan to construct power plants fired by oil shale, while Canada and Turkey plan to burn oil shale along with coal for power generation.
Oil shale serves as the main fuel for power generation only in Estonia, where the oil-shale-fired Narva Power Plants
accounted for 95% of electrical generation in 2005.
involve open pit mining and strip mining. These procedures remove most of the overlying material to expose the deposits of oil shale, and become practical when the deposits occur near the surface. Underground mining of oil shale, which removes less of the overlying material, employs the room-and-pillar method
.
The extraction of the useful components of oil shale usually takes place above ground (ex-situ processing), although several newer technologies perform this underground (on-site or in-situ processing).
In either case, the chemical process of pyrolysis
converts the kerogen in the oil shale to shale oil (synthetic crude
oil) and oil shale gas. Most conversion technologies involve heating shale in the absence of oxygen
to a temperature at which kerogen decomposes (pyrolyses) into gas, condensable oil, and a solid residue. This usually takes place between 450 °C (842 °F) and 500 °C (932 °F). The process of decomposition begins at relatively low temperatures (300 °C (572 °F)), but proceeds more rapidly and more completely at higher temperatures.
In-situ processing involves heating the oil shale underground. Such technologies can potentially extract more oil from a given area of land than ex-situ processes, since they can access the material at greater depths than surface mines can.
Several companies
have patented methods for in-situ retorting. However, most of these methods remain in the experimental phase. One can distinguish true in-situ processes (TIS) and modified in-situ processes (MIS). True in-situ processes do not involve mining the oil shale. Modified in-situ processes involve removing part of the oil shale and bringing it to the surface for modified in-situ retorting in order to create permeability for gas flow in a rubble chimney. Explosives rubblize the oil-shale deposit.
Hundreds of patents for oil shale retort
ing technologies exist;
however, only a few dozen have undergone testing. As of 2006, only four technologies remained in commercial use: Kiviter
, Galoter
, Fushun, and Petrosix
.
s; some of these plants employ the resulting heat
for district heating
of homes and businesses. Sizable oil-shale-fired power plant
s occur in Estonia, which has an installed capacity of 2,967 megawatts (MW), Israel (12.5 MW), China (12 MW), and Germany (9.9 MW).
In addition to its use as a fuel, oil shale may also serve in the production of specialty carbon fiber
s, adsorbent carbons
, carbon black
, phenols
, resin
s, glue
s, tanning
agents, mastic, road bitumen, cement
, bricks, construction and decorative blocks, soil-additives, fertilizer
s, rock-wool insulation, glass, and pharmaceutical products. However, oil shale use for production of these items remains small or only in its experimental stages. Some oil shales yield sulfur
, ammonia
, alumina, soda ash, uranium, and nahcolite
as shale-oil extraction byproducts. Between 1946 and 1952, a marine type of Dictyonema
shale served for uranium
production in Sillamäe
, Estonia, and between 1950 and 1989 Sweden used alum
shale for the same purposes. Oil shale gas has served as a substitute for natural gas
, but , producing oil shale gas as a natural-gas substitute remained economically infeasible.
The shale oil derived from oil shale does not directly substitute for crude oil in all applications. It may contain higher concentrations of olefins, oxygen
, and nitrogen
than conventional crude oil. Some shale oils may have higher sulfur or arsenic content. By comparison with West Texas Intermediate
, the benchmark standard for crude oil in the futures-contract
market, the Green River shale oil sulfur
content ranges from near 0% to 4.9% (in average 0.76%), where West Texas Intermediate's sulfur content has a maximum of 0.42%. The sulfur content in shale oil from Jordan's oil shales may rise even up to 9.5%.
The arsenic content, for example, becomes an issue for Green River formation oil shale. The higher concentrations of these materials means that the oil must undergo considerable upgrading (hydrotreating
) before serving as oil-refinery
feedstock.
Above-ground retorting processes tended to yield a lower API gravity
shale oil than the in situ processes. Shale oil serves best for producing middle-distillates
such as kerosene
, jet fuel
, and diesel fuel. Worldwide demand for these middle distillates, particularly for diesel fuels, increased rapidly in the 1990s and 2000s. However, appropriate refining processes equivalent to hydrocracking can transform shale oil into a lighter-range hydrocarbon (gasoline
).
During the early 20th century, the crude-oil industry expanded. Since then, the various attempts to develop oil shale deposits have succeeded only when the cost of shale-oil production in a given region comes in below the price of crude oil or its other substitutes. According to a survey conducted by the RAND Corporation, the cost of producing a barrel of oil at a surface retorting complex in the United States (comprising a mine, retorting plant
, upgrading plant
, supporting utilities, and spent shale reclamation), would range between US$70–95 ($440–600/m3, adjusted to 2005 values). This estimate considers varying levels of kerogen quality and extraction efficiency. In order to run a profitable operation, the price of crude oil would need to remain above these levels. The analysis also discusses the expectation that processing costs would drop after the establishment of the complex. The hypothetical unit would see a cost reduction of 35–70% after producing its first 500 Moilbbl. Assuming an increase in output of 25 koilbbl/d during each year after the start of commercial production, RAND predicts the costs would decline to $35–48 per barrel ($220–300/m3) within 12 years. After achieving the milestone of 1 Goilbbl, its costs would decline further to $30–40 per barrel ($190–250/m3).
Some commentators compare the proposed American oil-shale industry to the Athabasca oil-sands
industry (the latter enterprise generated over 1 Moilbbl of oil per day in late 2007), stating that "the first-generation facility is the hardest, both technically and economically".
Royal Dutch Shell
has announced that its in situ extraction technology in Colorado could become competitive at prices over $30 per barrel ($190/m3), while other technologies at full-scale production assert profitability at oil prices even lower than $20 per barrel ($130/m3).
To increase efficiency when retorting oil shale, researchers have proposed and tested several co-pyrolysis processes.
A 1972 publication in the journal Pétrole Informations compared shale-based oil production unfavorably with the coal liquefaction
. The article portrayed coal liquefaction as less expensive, generating more oil, and creating fewer environmental impacts than extraction from oil shale. It cited a conversion ration of 650 litre of oil per one ton
of coal, as against 150 litre of shale oil per one ton of oil shale.
A critical measure of the viability of oil shale as an energy source lies in the ratio of the energy produced by the shale to the energy used in its mining and processing, a ratio known as "Energy Returned on Energy Invested" (EROEI
). A 1984 study estimated the EROEI of the various known oil-shale deposits as varying between 0.7–13.3
although known oil-shale extraction development projects assert an EROEI between 3 to 10. Royal Dutch Shell has reported an EROEI of three to four on its in situ development, Mahogany Research Project
.
The water needed in the oil shale retorting process offers an additional economic consideration: this may pose a problem in areas with water scarcity.
into surface-water and groundwater, increased erosion
, sulfur-gas emissions, and air pollution caused by the production of particulates
during processing, transport, and support activities. In 2002, about 97% of air pollution, 86% of total waste and 23% of water pollution in Estonia came from the power industry, which uses oil shale as the main resource for its power production.
Oil-shale extraction can damage the biological and recreational value of land and the ecosystem in the mining area. Combustion and thermal processing generate waste material. In addition, the atmospheric emissions from oil shale processing and combustion include carbon dioxide
, a greenhouse gas
. Environmentalists oppose production and usage of oil shale, as it creates even more greenhouse gases than conventional fossil fuels.
Section 526 of the Energy Independence And Security Act prohibits United States government agencies from buying oil produced by processes that produce more greenhouse gas emissions than would traditional petroleum.
Experimental in situ conversion processes and carbon capture and storage
technologies may reduce some of these concerns in the future, but at the same time they may cause other problems, including groundwater
pollution. Among the water contaminants commonly associated with oil shale processing are oxygen and nitrogen heterocyclic hydrocarbons. Commonly detected examples include quinoline
derivatives, pyridine
, and various alkyl homologues of pyridine (picoline
, lutidine).
Some commentators have expressed concerns over the oil shale industry's use of water. In 2002, the oil shale-fired power industry used 91% of the water consumed in Estonia. Depending on technology, above-ground retorting uses between one and five barrels of water per barrel of produced shale-oil. A 2008 programmatic environmental impact statement
issued by the US Bureau of Land Management
stated that surface mining and retort operations produce 2 gallon of waste water per 1 short ton (0.892854426455391 LT) of processed oil shale. In situ processing, according to one estimate, uses about one-tenth as much water.
Water concerns become particularly sensitive issues in arid regions, such as the western US and Israel's Negev Desert
, where plans exist to expand oil-shale extraction despite a water shortage.
Environmental
activists, including members of Greenpeace
, have organized strong protests against the oil shale industry. In one result, Queensland Energy Resources
put the proposed Stuart Oil Shale Project
in Australia on hold in 2004.
Sedimentary rock
Sedimentary rock are types of rock that are formed by the deposition of material at the Earth's surface and within bodies of water. Sedimentation is the collective name for processes that cause mineral and/or organic particles to settle and accumulate or minerals to precipitate from a solution....
, contains significant amounts of kerogen
Kerogen
Kerogen is a mixture of organic chemical compounds that make up a portion of the organic matter in sedimentary rocks. It is insoluble in normal organic solvents because of the huge molecular weight of its component compounds. The soluble portion is known as bitumen. When heated to the right...
(a solid mixture of organic chemical compound
Chemical compound
A chemical compound is a pure chemical substance consisting of two or more different chemical elements that can be separated into simpler substances by chemical reactions. Chemical compounds have a unique and defined chemical structure; they consist of a fixed ratio of atoms that are held together...
s) from which liquid hydrocarbon
Hydrocarbon
In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons from which one hydrogen atom has been removed are functional groups, called hydrocarbyls....
s called shale oil
Shale oil
Shale oil, known also as kerogen oil or oil-shale oil, is an unconventional oil produced from oil shale by pyrolysis, hydrogenation, or thermal dissolution. These processes convert the organic matter within the rock into synthetic oil and gas...
(not to be confused with tight oil
Tight Oil
Tight oil is a light crude oil contained in petroleum-bearing formations of relatively low porosity and permeability . It uses the same horizontal well and hydraulic fracturing technology used in recent boom in production of shale gas...
—crude oil
Petroleum
Petroleum or crude oil is a naturally occurring, flammable liquid consisting of a complex mixture of hydrocarbons of various molecular weights and other liquid organic compounds, that are found in geologic formations beneath the Earth's surface. Petroleum is recovered mostly through oil drilling...
occurring naturally in shales) can be produced. Shale oil is a substitute for conventional crude oil; however, extracting shale oil from oil shale is more costly than the production of conventional crude oil both financially and in terms of its environmental impact.
Deposits
Deposition (geology)
Deposition is the geological process by which material is added to a landform or land mass. Fluids such as wind and water, as well as sediment flowing via gravity, transport previously eroded sediment, which, at the loss of enough kinetic energy in the fluid, is deposited, building up layers of...
of oil shale occur around the world, including major deposits in the United States of America. Estimates of global deposits range from 2.8 Toilbbl of recoverable oil.
Heating oil shale to a sufficiently high temperature causes the chemical process of pyrolysis
Pyrolysis
Pyrolysis is a thermochemical decomposition of organic material at elevated temperatures without the participation of oxygen. It involves the simultaneous change of chemical composition and physical phase, and is irreversible...
to yield
Yield (chemistry)
In chemistry, yield, also referred to as chemical yield and reaction yield, is the amount of product obtained in a chemical reaction. The absolute yield can be given as the weight in grams or in moles...
a vapor
Vapor
A vapor or vapour is a substance in the gas phase at a temperature lower than its critical point....
. Upon cooling the vapor, the liquid shale oil
Shale oil
Shale oil, known also as kerogen oil or oil-shale oil, is an unconventional oil produced from oil shale by pyrolysis, hydrogenation, or thermal dissolution. These processes convert the organic matter within the rock into synthetic oil and gas...
—an unconventional oil—is separated from combustible
Combustibility
Combustibility is a measure of how easily a substance will set on fire, through fire or combustion. This is an important property to consider when a substance is used for construction or is being stored. Special precautions are usually required for substances that are easily combustible...
oil-shale gas
Oil shale gas
Oil shale gas is a synthetic gas mixture produced by oil shale pyrolysis. Although often referred to as shale gas, it differs from the natural gas produced from shale, which is also known as shale gas.-Process:...
(the term shale gas
Shale gas
Shale gas is natural gas produced from shale. Shale gas has become an increasingly important source of natural gas in the United States over the past decade, and interest has spread to potential gas shales in the rest of the world...
can also refer to gas occurring naturally in shales). Oil shale can also be burnt
Combustion
Combustion or burning is the sequence of exothermic chemical reactions between a fuel and an oxidant accompanied by the production of heat and conversion of chemical species. The release of heat can result in the production of light in the form of either glowing or a flame...
directly in furnaces as a low-grade fuel for power generation
Electricity generation
Electricity generation is the process of generating electric energy from other forms of energy.The fundamental principles of electricity generation were discovered during the 1820s and early 1830s by the British scientist Michael Faraday...
and district heating
District heating
District heating is a system for distributing heat generated in a centralized location for residential and commercial heating requirements such as space heating and water heating...
or used as a raw material in chemical and construction-materials processing.
Oil shale gains attention as a potential abundant source of oil whenever the price of crude oil rises. At the same time, oil-shale mining and processing raise a number of environmental concerns, such as land use
Land use
Land use is the human use of land. Land use involves the management and modification of natural environment or wilderness into built environment such as fields, pastures, and settlements. It has also been defined as "the arrangements, activities and inputs people undertake in a certain land cover...
, waste disposal
Waste management
Waste management is the collection, transport, processing or disposal,managing and monitoring of waste materials. The term usually relates to materials produced by human activity, and the process is generally undertaken to reduce their effect on health, the environment or aesthetics...
, water use
Water resources
Water resources are sources of water that are useful or potentially useful. Uses of water include agricultural, industrial, household, recreational and environmental activities. Virtually all of these human uses require fresh water....
, waste-water management
Water pollution
Water pollution is the contamination of water bodies . Water pollution occurs when pollutants are discharged directly or indirectly into water bodies without adequate treatment to remove harmful compounds....
, greenhouse-gas emissions and air pollution
Air pollution
Air pollution is the introduction of chemicals, particulate matter, or biological materials that cause harm or discomfort to humans or other living organisms, or cause damage to the natural environment or built environment, into the atmosphere....
. Estonia
Estonia
Estonia , officially the Republic of Estonia , is a state in the Baltic region of Northern Europe. It is bordered to the north by the Gulf of Finland, to the west by the Baltic Sea, to the south by Latvia , and to the east by Lake Peipsi and the Russian Federation . Across the Baltic Sea lies...
and China have well-established oil shale industries, and Brazil
Brazil
Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...
, Germany, Israel
Israel
The State of Israel is a parliamentary republic located in the Middle East, along the eastern shore of the Mediterranean Sea...
and Russia also utilize oil shale.
Oil shales differ from oil-bearing shales, shale deposits which contain petroleum (tight oil
Tight Oil
Tight oil is a light crude oil contained in petroleum-bearing formations of relatively low porosity and permeability . It uses the same horizontal well and hydraulic fracturing technology used in recent boom in production of shale gas...
) that is sometimes produced from drilled wells. Examples of oil-bearing shales are the Bakken Formation
Bakken Formation
The Bakken formation, initially described by geologist J.W. Nordquist in 1953,is a rock unit from the Late Devonian to Early Mississippian age occupying about of the subsurface of the Williston Basin, underlying parts of Montana, North Dakota, and Saskatchewan...
, Pierre Shale
Pierre Shale
The Pierre Shale is a geologic formation or series in the Upper Cretaceous which occurs east of the Rocky Mountains in the Great Plains, from North Dakota to New Mexico....
, Niobrara Formation
Niobrara Formation
The Niobrara Formation, also called the Niobrara Chalk , is a geologic formation in North America that was laid down between 87 and 82 million years ago during the Coniacian, Santonian, and Campanian ages of the Late Cretaceous. It is composed of two structural units, the Smoky Hill Chalk Member...
, and Eagle Ford Formation
Eagle Ford Formation
The Eagle Ford Formation is a sedimentary rock formation from the Late Cretaceous age underlying much of South and East Texas in United States, consisting of organic matter-rich fossiliferous marine shale...
.
Geology
Sapropel
Sapropel is a term used in marine geology to describe dark-coloured sediments that are rich in organic matter...
fuel
Fuel
Fuel is any material that stores energy that can later be extracted to perform mechanical work in a controlled manner. Most fuels used by humans undergo combustion, a redox reaction in which a combustible substance releases energy after it ignites and reacts with the oxygen in the air...
s.
It does not have a definite geological definition nor a specific chemical formula, and its seams do not always have discrete boundaries. Oil shales vary considerably in their mineral content, chemical composition, age, type of kerogen, and depositional history and not all oil shales would necessarily be classified as shale
Shale
Shale is a fine-grained, clastic sedimentary rock composed of mud that is a mix of flakes of clay minerals and tiny fragments of other minerals, especially quartz and calcite. The ratio of clay to other minerals is variable. Shale is characterized by breaks along thin laminae or parallel layering...
s in the strict sense. Oil shale differs from bitumen-impregnated rocks
Bituminous rocks
Organic-rich sedimentary rocks are a specific type of sedimentary rock that contains significant amounts of organic carbon. The most common types include coal, lignite, oil shale, or black shale...
(oil sands and petroleum reservoir rocks), humic
Humic acid
Humic acid is a principal component of humic substances, which are the major organic constituents of soil , peat, coal, many upland streams, dystrophic lakes, and ocean water. It is produced by biodegradation of dead organic matter...
coals and carbonaceous
Carbonaceous
Carbonaceous is the defining attribute of a substance rich in carbon. Particularly, carbonaceous hydrocarbons are very unsaturated, high-molecular-weight hydrocarbons, having an elevated carbon:hydrogen ratio....
shale
Shale
Shale is a fine-grained, clastic sedimentary rock composed of mud that is a mix of flakes of clay minerals and tiny fragments of other minerals, especially quartz and calcite. The ratio of clay to other minerals is variable. Shale is characterized by breaks along thin laminae or parallel layering...
. While oil sands originate from the biodegradation
Biodegradation
Biodegradation or biotic degradation or biotic decomposition is the chemical dissolution of materials by bacteria or other biological means...
of oil, heat and pressure have not (yet) transformed the kerogen in oil shale into petroleum.
Oil shale contains a lower percentage of organic matter than coal. In commercial grades of oil shale the ratio of organic matter to mineral matter lies approximately between 0.75:5 and 1.5:5. At the same time, the organic matter in oil shale has an atomic ratio of hydrogen to carbon (H/C) approximately 1.2 to 1.8 times lower than for crude oil and about 1.5 to 3 times higher than for coals. The organic components of oil shale derive from a variety of organisms, such as the remains of algae
Algae
Algae are a large and diverse group of simple, typically autotrophic organisms, ranging from unicellular to multicellular forms, such as the giant kelps that grow to 65 meters in length. They are photosynthetic like plants, and "simple" because their tissues are not organized into the many...
, spore
Spore
In biology, a spore is a reproductive structure that is adapted for dispersal and surviving for extended periods of time in unfavorable conditions. Spores form part of the life cycles of many bacteria, plants, algae, fungi and some protozoa. According to scientist Dr...
s, pollen
Pollen
Pollen is a fine to coarse powder containing the microgametophytes of seed plants, which produce the male gametes . Pollen grains have a hard coat that protects the sperm cells during the process of their movement from the stamens to the pistil of flowering plants or from the male cone to the...
, plant cuticle
Plant cuticle
Plant cuticles are a protective waxy covering produced only by the epidermal cells of leaves, young shoots and all other aerial plant organs without periderm...
s and corky fragments of herbaceous
Herbaceous
A herbaceous plant is a plant that has leaves and stems that die down at the end of the growing season to the soil level. They have no persistent woody stem above ground...
and woody plants, and cellular debris from other aquatic and land plants.
Some deposits contain significant fossil
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
s; Germany's Messel Pit
Messel pit
The Messel Pit is a disused quarry near the village of Messel, about southeast of Frankfurt am Main, Germany. Bituminous shale was mined there. Because of its abundance of fossils, it has significant geological and scientific importance...
has the status of a Unesco World Heritage Site. The mineral matter in oil shale includes various fine-grained silicate
Silicon dioxide
The chemical compound silicon dioxide, also known as silica , is an oxide of silicon with the chemical formula '. It has been known for its hardness since antiquity...
s and carbonates
Carbonate minerals
Carbonate minerals are those minerals containing the carbonate ion: CO32-.-Anhydrous carbonates:*Calcite group: Trigonal**Calcite CaCO3**Gaspeite CO3**Magnesite MgCO3**Otavite CdCO3**Rhodochrosite MnCO3**Siderite FeCO3**Smithsonite ZnCO3...
.
Geologists can classify oil shales on the basis of their composition as carbonate
Carbonate
In chemistry, a carbonate is a salt of carbonic acid, characterized by the presence of the carbonate ion, . The name may also mean an ester of carbonic acid, an organic compound containing the carbonate group C2....
-rich shales, siliceous shales, or cannel
Cannel coal
Cannel coal, also known as candle coal, is a type of coal, also classified as terrestrial type oil shale, with a large amount of hydrogen, which burns easily with a bright light and leaves little ash....
shales.
Another classification, known as the van Krevelen diagram, assigns kerogen types, depending on the hydrogen
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
, carbon
Carbon
Carbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds...
, and oxygen
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
content of oil shales' original organic matter. The most commonly used classification of oil shales, developed between 1987 and 1991 by Adrian C. Hutton of the University of Wollongong
University of Wollongong
The University of Wollongong is a public university located in the coastal city of Wollongong, New South Wales, Australia, approximately 80 kilometres south of Sydney...
, adapts petrographic
Petrography
Petrography is a branch of petrology that focuses on detailed descriptions of rocks. Someone who studies petrography is called a petrographer. The mineral content and the textural relationships within the rock are described in detail. Petrographic descriptions start with the field notes at the...
terms from coal terminology. This classification designates oil shales as terrestrial, lacustrine
Lake
A lake is a body of relatively still fresh or salt water of considerable size, localized in a basin, that is surrounded by land. Lakes are inland and not part of the ocean and therefore are distinct from lagoons, and are larger and deeper than ponds. Lakes can be contrasted with rivers or streams,...
(lake-bottom-deposited), or marine
Marine (ocean)
Marine is an umbrella term. As an adjective it is usually applicable to things relating to the sea or ocean, such as marine biology, marine ecology and marine geology...
(ocean bottom-deposited), based on the environment of the initial biomass
Biomass
Biomass, as a renewable energy source, is biological material from living, or recently living organisms. As an energy source, biomass can either be used directly, or converted into other energy products such as biofuel....
deposit. Hutton's classification scheme has proven useful in estimating the yield and composition of the extracted oil.
Reserves
Although resources of oil shale occur in many countries, only 33 countries possess known deposits of possible economic value.
Well-explored deposits, potentially classifiable as reserves, include the Green River
Green River Formation
The Green River Formation is an Eocene geologic formation that records the sedimentation in a group of intermountain lakes. The sediments are deposited in very fine layers, a dark layer during the growing season and a light-hue inorganic layer in winter. Each pair of layers is called a varve and...
deposits in the western United States, the Tertiary deposits in Queensland
Queensland
Queensland is a state of Australia, occupying the north-eastern section of the mainland continent. It is bordered by the Northern Territory, South Australia and New South Wales to the west, south-west and south respectively. To the east, Queensland is bordered by the Coral Sea and Pacific Ocean...
, Australia, deposits in Sweden
Sweden
Sweden , officially the Kingdom of Sweden , is a Nordic country on the Scandinavian Peninsula in Northern Europe. Sweden borders with Norway and Finland and is connected to Denmark by a bridge-tunnel across the Öresund....
and Estonia
Estonia
Estonia , officially the Republic of Estonia , is a state in the Baltic region of Northern Europe. It is bordered to the north by the Gulf of Finland, to the west by the Baltic Sea, to the south by Latvia , and to the east by Lake Peipsi and the Russian Federation . Across the Baltic Sea lies...
, the El-Lajjun deposit in Jordan
Jordan
Jordan , officially the Hashemite Kingdom of Jordan , Al-Mamlaka al-Urduniyya al-Hashemiyya) is a kingdom on the East Bank of the River Jordan. The country borders Saudi Arabia to the east and south-east, Iraq to the north-east, Syria to the north and the West Bank and Israel to the west, sharing...
, and deposits in France, Germany, Brazil
Brazil
Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...
, China, southern Mongolia
Mongolia
Mongolia is a landlocked country in East and Central Asia. It is bordered by Russia to the north and China to the south, east and west. Although Mongolia does not share a border with Kazakhstan, its western-most point is only from Kazakhstan's eastern tip. Ulan Bator, the capital and largest...
and Russia. These deposits have given rise to expectations of yielding at least 40 liters of shale oil per tonne of oil shale, using the Fischer Assay
Fischer Assay
The Fischer assay is a standardized laboratory test for determining the oil yield from oil shale to be expected from a conventional shale oil extraction. A 100 gram oil shale sample crushed to...
.
A 2005 estimate set the total world resources of oil shale at 411 gigatons — enough to yield 2.8 Toilbbl of shale oil. This exceeds the world's proven conventional oil reserves
Oil reserves
The total estimated amount of oil in an oil reservoir, including both producible and non-producible oil, is called oil in place. However, because of reservoir characteristics and limitations in petroleum extraction technologies, only a fraction of this oil can be brought to the surface, and it is...
, estimated at 1.317 Toilbbl, as of 1 January 2007. The largest deposits in the world occur in the United States in the Green River Formation
Green River Formation
The Green River Formation is an Eocene geologic formation that records the sedimentation in a group of intermountain lakes. The sediments are deposited in very fine layers, a dark layer during the growing season and a light-hue inorganic layer in winter. Each pair of layers is called a varve and...
, which covers portions of Colorado
Colorado
Colorado is a U.S. state that encompasses much of the Rocky Mountains as well as the northeastern portion of the Colorado Plateau and the western edge of the Great Plains...
, Utah
Utah
Utah is a state in the Western United States. It was the 45th state to join the Union, on January 4, 1896. Approximately 80% of Utah's 2,763,885 people live along the Wasatch Front, centering on Salt Lake City. This leaves vast expanses of the state nearly uninhabited, making the population the...
, and Wyoming
Wyoming
Wyoming is a state in the mountain region of the Western United States. The western two thirds of the state is covered mostly with the mountain ranges and rangelands in the foothills of the Eastern Rocky Mountains, while the eastern third of the state is high elevation prairie known as the High...
; about 70% of this resource lies on land owned or managed by the United States federal government.
Deposits in the United States constitute 62% of world resources; together, the United States, Russia and Brazil account for 86% of the world's resources in terms of shale-oil content. These figures remain tentative, with exploration or analysis of several deposits still outstanding. Professor Alan R. Carroll of University of Wisconsin–Madison
University of Wisconsin–Madison
The University of Wisconsin–Madison is a public research university located in Madison, Wisconsin, United States. Founded in 1848, UW–Madison is the flagship campus of the University of Wisconsin System. It became a land-grant institution in 1866...
regards the Upper Permian lacustrine oil-shale deposits of northwest China, absent from previous global oil shale assessments, as comparable in size to the Green River Formation.
History
Humans have used oil shale as a fuel since prehistoric times, since it generally burns without any processing.Britons
Britons (historical)
The Britons were the Celtic people culturally dominating Great Britain from the Iron Age through the Early Middle Ages. They spoke the Insular Celtic language known as British or Brythonic...
of the Iron Age
Iron Age
The Iron Age is the archaeological period generally occurring after the Bronze Age, marked by the prevalent use of iron. The early period of the age is characterized by the widespread use of iron or steel. The adoption of such material coincided with other changes in society, including differing...
also used to polish it and form it into ornaments.
Modern industrial mining of oil shale began in 1837 in Autun
Autun
Autun is a commune in the Saône-et-Loire department in Burgundy in eastern France. It was founded during the early Roman Empire as Augustodunum. Autun marks the easternmost extent of the Umayyad campaign in Europe.-Early history:...
, France, followed by exploitation in Scotland, Germany, and several other countries.
Operations during the 19th century focused on the production of kerosene
Kerosene
Kerosene, sometimes spelled kerosine in scientific and industrial usage, also known as paraffin or paraffin oil in the United Kingdom, Hong Kong, Ireland and South Africa, is a combustible hydrocarbon liquid. The name is derived from Greek keros...
, lamp oil, and paraffin
Paraffin
In chemistry, paraffin is a term that can be used synonymously with "alkane", indicating hydrocarbons with the general formula CnH2n+2. Paraffin wax refers to a mixture of alkanes that falls within the 20 ≤ n ≤ 40 range; they are found in the solid state at room temperature and begin to enter the...
; these products helped supply the growing demand for lighting that arose during the Industrial Revolution
Industrial Revolution
The Industrial Revolution was a period from the 18th to the 19th century where major changes in agriculture, manufacturing, mining, transportation, and technology had a profound effect on the social, economic and cultural conditions of the times...
. Fuel oil, lubricating oil and grease, and ammonium sulfate
Ammonium sulfate
Ammonium sulfate , 2SO4, is an inorganic salt with a number of commercial uses. The most common use is as a soil fertilizer. It contains 21% nitrogen as ammonium cations, and 24% sulfur as sulfate anions...
were also produced.
The European oil-shale industry expanded immediately before World War I
World War I
World War I , which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918...
due to limited access to conventional petroleum resources and to the mass production of automobiles and trucks, which accompanied an increase in gasoline consumption.
Although the Estonian and Chinese oil-shale industries continued to grow after World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
, most other countries abandoned their projects due to high processing costs and the availability of cheaper petroleum.
Following the 1973 oil crisis
1973 oil crisis
The 1973 oil crisis started in October 1973, when the members of Organization of Arab Petroleum Exporting Countries or the OAPEC proclaimed an oil embargo. This was "in response to the U.S. decision to re-supply the Israeli military" during the Yom Kippur war. It lasted until March 1974. With the...
, world production of oil shale reached a peak of 46 million tonnes in 1980 before falling to about 16 million tonnes in 2000, due to competition from cheap conventional petroleum in the 1980s
1980s oil glut
The 1980s oil glut was a serious surplus of crude oil caused by falling demand following the 1970s Energy Crisis. The world price of oil, which had peaked in 1980 at over US$35 per barrel , fell in 1986 from $27 to below $10...
.
On 2 May 1982, known in some circles as "Black Sunday", Exxon
ExxonMobil
Exxon Mobil Corporation or ExxonMobil, is an American multinational oil and gas corporation. It is a direct descendant of John D. Rockefeller's Standard Oil company, and was formed on November 30, 1999, by the merger of Exxon and Mobil. Its headquarters are in Irving, Texas...
canceled its US$5 billion Colony Shale Oil Project
Colony Shale Oil Project
Colony Shale Oil Project was an oil shale development project at the Piceance Basin near Parachute Creek, Colorado. The project consisted of an oil shale mine and pilot-scale shale oil plant, which used the TOSCO II retorting technology, developed by Tosco Corporation...
near Parachute, Colorado
Parachute, Colorado
The Town of Parachute is a Statutory Town in Garfield County, Colorado, United States. The population was 1,006 at the 2000 census.-Geography:Parachute is located at ....
because of low oil-prices and increased expenses, laying off more than 2,000 workers and leaving a trail of home-foreclosures and small-business bankruptcies.
In 1986, President Ronald Reagan
Ronald Reagan
Ronald Wilson Reagan was the 40th President of the United States , the 33rd Governor of California and, prior to that, a radio, film and television actor....
signed into law the Consolidated Omnibus Budget Reconciliation Act of 1985
Consolidated Omnibus Budget Reconciliation Act of 1985
The Consolidated Omnibus Budget Reconciliation Act of 1985 is a law passed by the U.S. Congress on a reconciliation basis and signed by President Reagan that, among other things, mandates an insurance program giving some employees the ability to continue health insurance coverage after leaving...
which among other things abolished the United States' Synthetic Liquid Fuels Program
Synthetic Liquid Fuels Program
The Synthetic Liquid Fuels Program was a program run by the United States Bureau of Mines to create the technology to produce synthetic fuel from coal. It was initiated in 1944 during World War II...
.
The global oil-shale industry began to revive at the beginning of the 21st century. In 2003, an oil-shale development program restarted in the United States. Authorities introduced a commercial leasing program permitting the extraction of oil shale and oil sands on federal lands in 2005, in accordance with the Energy Policy Act of 2005
Energy Policy Act of 2005
The Energy Policy Act of 2005 is a bill passed by the United States Congress on July 29, 2005, and signed into law by President George W. Bush on August 8, 2005, at Sandia National Laboratories in Albuquerque, New Mexico...
.
Industry
Brazil
Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...
, China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...
, Estonia
Estonia
Estonia , officially the Republic of Estonia , is a state in the Baltic region of Northern Europe. It is bordered to the north by the Gulf of Finland, to the west by the Baltic Sea, to the south by Latvia , and to the east by Lake Peipsi and the Russian Federation . Across the Baltic Sea lies...
and to some extent in Germany
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...
, Israel, and Russia
Russia
Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...
. Several additional countries started assessing their reserves or had built experimental production plants, while others had phased out their oil shale industry. Oil shale serves for oil production in Estonia, Brazil, and China; for power generation in Estonia, China, Israel, and Germany; for cement production in Estonia, Germany, and China; and for use in chemical industries in China, Estonia, and Russia.
, 80% of oil shale used globally is extracted in Estonia.
Romania
Romania
Romania is a country located at the crossroads of Central and Southeastern Europe, on the Lower Danube, within and outside the Carpathian arch, bordering on the Black Sea...
and Russia have in the past run power plant
Power station
A power station is an industrial facility for the generation of electric energy....
s fired by oil shale, but have shut them down or switched to other fuel sources such as natural gas
Natural gas
Natural gas is a naturally occurring gas mixture consisting primarily of methane, typically with 0–20% higher hydrocarbons . It is found associated with other hydrocarbon fuel, in coal beds, as methane clathrates, and is an important fuel source and a major feedstock for fertilizers.Most natural...
. Jordan
Jordan oil shale power station
Jordan oil shale power station is a project to build an oil shale-fueled power station in Jordan. The agreement between the Ministry of Energy and Mineral Resources and National Electricity Power Company of Jordan, and Estonian power company Eesti Energia was signed on 30 April 2008...
and Egypt
Egypt
Egypt , officially the Arab Republic of Egypt, Arabic: , is a country mainly in North Africa, with the Sinai Peninsula forming a land bridge in Southwest Asia. Egypt is thus a transcontinental country, and a major power in Africa, the Mediterranean Basin, the Middle East and the Muslim world...
plan to construct power plants fired by oil shale, while Canada and Turkey plan to burn oil shale along with coal for power generation.
Oil shale serves as the main fuel for power generation only in Estonia, where the oil-shale-fired Narva Power Plants
Narva Power Plants
The Narva Power Plants are a power generation complex in Narva in Estonia, near the border with Leningrad Oblast, Russia. The complex consists of the world's two largest oil shale-fired thermal power plants, Eesti Power Plant and Balti Power Plant . In 2007, Narva Power Plants generated about...
accounted for 95% of electrical generation in 2005.
Extraction and processing
Most exploitation of oil shale involves mining followed by shipping elsewhere, after which one can burn the shale directly to generate electricity, or undertake further processing. The most common methods of surface miningSurface mining
Surface mining , is a type of mining in which soil and rock overlying the mineral deposit are removed...
involve open pit mining and strip mining. These procedures remove most of the overlying material to expose the deposits of oil shale, and become practical when the deposits occur near the surface. Underground mining of oil shale, which removes less of the overlying material, employs the room-and-pillar method
Room and pillar
Room and pillar is a mining system in which the mined material is extracted across a horizontal plane while leaving "pillars" of untouched material to support the roof overburden leaving open areas or "rooms" underground...
.
The extraction of the useful components of oil shale usually takes place above ground (ex-situ processing), although several newer technologies perform this underground (on-site or in-situ processing).
In either case, the chemical process of pyrolysis
Pyrolysis
Pyrolysis is a thermochemical decomposition of organic material at elevated temperatures without the participation of oxygen. It involves the simultaneous change of chemical composition and physical phase, and is irreversible...
converts the kerogen in the oil shale to shale oil (synthetic crude
Synthetic crude
Synthetic crude is the output from a bitumen/extra heavy oil upgrader facility used in connection with oil sand production. It may also refer to shale oil, an output from an oil shale pyrolysis. The properties of the synthetic crude depend on the processes used in the upgrading. Typically, it is...
oil) and oil shale gas. Most conversion technologies involve heating shale in the absence of oxygen
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
to a temperature at which kerogen decomposes (pyrolyses) into gas, condensable oil, and a solid residue. This usually takes place between 450 °C (842 °F) and 500 °C (932 °F). The process of decomposition begins at relatively low temperatures (300 °C (572 °F)), but proceeds more rapidly and more completely at higher temperatures.
In-situ processing involves heating the oil shale underground. Such technologies can potentially extract more oil from a given area of land than ex-situ processes, since they can access the material at greater depths than surface mines can.
Several companies
Company
A company is a form of business organization. It is an association or collection of individual real persons and/or other companies, who each provide some form of capital. This group has a common purpose or focus and an aim of gaining profits. This collection, group or association of persons can be...
have patented methods for in-situ retorting. However, most of these methods remain in the experimental phase. One can distinguish true in-situ processes (TIS) and modified in-situ processes (MIS). True in-situ processes do not involve mining the oil shale. Modified in-situ processes involve removing part of the oil shale and bringing it to the surface for modified in-situ retorting in order to create permeability for gas flow in a rubble chimney. Explosives rubblize the oil-shale deposit.
Hundreds of patents for oil shale retort
Retort
In a chemistry laboratory, a retort is a glassware device used for distillation or dry distillation of substances. It consists of a spherical vessel with a long downward-pointing neck. The liquid to be distilled is placed in the vessel and heated...
ing technologies exist;
however, only a few dozen have undergone testing. As of 2006, only four technologies remained in commercial use: Kiviter
Kiviter process
-History:The Kiviter process is based on the earlier vertical retort technology . This technology underwent a long process of development...
, Galoter
Galoter process
The Galoter process is a shale oil extraction technology for a production of shale oil, a type of synthetic crude oil. In this process, the oil shale is decomposed into shale oil, oil shale gas, and spent residue...
, Fushun, and Petrosix
Petrosix
Petrosix is currently the world’s largest surface oil shale pyrolysis retort with an diameter vertical shaft kiln, operational since 1992. It is located in São Mateus do Sul, Brazil, and it is owned and operated by the Brazil energy company Petrobras. Petrosix means also the Petrosix process, an...
.
Applications and products
Industry can use oil shale as a fuel for thermal power-plants, burning it (like coal) to drive steam turbineSteam turbine
A steam turbine is a mechanical device that extracts thermal energy from pressurized steam, and converts it into rotary motion. Its modern manifestation was invented by Sir Charles Parsons in 1884....
s; some of these plants employ the resulting heat
Cogeneration
Cogeneration is the use of a heat engine or a power station to simultaneously generate both electricity and useful heat....
for district heating
District heating
District heating is a system for distributing heat generated in a centralized location for residential and commercial heating requirements such as space heating and water heating...
of homes and businesses. Sizable oil-shale-fired power plant
Fossil fuel power plant
A fossil-fuel power station is a power station that burns fossil fuels such as coal, natural gas or petroleum to produce electricity. Central station fossil-fuel power plants are designed on a large scale for continuous operation...
s occur in Estonia, which has an installed capacity of 2,967 megawatts (MW), Israel (12.5 MW), China (12 MW), and Germany (9.9 MW).
In addition to its use as a fuel, oil shale may also serve in the production of specialty carbon fiber
Carbon fiber
Carbon fiber, alternatively graphite fiber, carbon graphite or CF, is a material consisting of fibers about 5–10 μm in diameter and composed mostly of carbon atoms. The carbon atoms are bonded together in crystals that are more or less aligned parallel to the long axis of the fiber...
s, adsorbent carbons
Adsorption
Adsorption is the adhesion of atoms, ions, biomolecules or molecules of gas, liquid, or dissolved solids to a surface. This process creates a film of the adsorbate on the surface of the adsorbent. It differs from absorption, in which a fluid permeates or is dissolved by a liquid or solid...
, carbon black
Carbon black
Carbon black is a material produced by the incomplete combustion of heavy petroleum products such as FCC tar, coal tar, ethylene cracking tar, and a small amount from vegetable oil. Carbon black is a form of amorphous carbon that has a high surface-area-to-volume ratio, although its...
, phenols
Phenols
In organic chemistry, phenols, sometimes called phenolics, are a class of chemical compounds consisting of a hydroxyl group bonded directly to an aromatic hydrocarbon group...
, resin
Resin
Resin in the most specific use of the term is a hydrocarbon secretion of many plants, particularly coniferous trees. Resins are valued for their chemical properties and associated uses, such as the production of varnishes, adhesives, and food glazing agents; as an important source of raw materials...
s, glue
Glue
This is a list of various types of glue. Historically, the term "glue" only referred to protein colloids prepared from animal flesh. The meaning has been extended to refer to any fluid adhesive....
s, tanning
Tanning
Tanning is the making of leather from the skins of animals which does not easily decompose. Traditionally, tanning used tannin, an acidic chemical compound from which the tanning process draws its name . Coloring may occur during tanning...
agents, mastic, road bitumen, cement
Cement
In the most general sense of the word, a cement is a binder, a substance that sets and hardens independently, and can bind other materials together. The word "cement" traces to the Romans, who used the term opus caementicium to describe masonry resembling modern concrete that was made from crushed...
, bricks, construction and decorative blocks, soil-additives, fertilizer
Fertilizer
Fertilizer is any organic or inorganic material of natural or synthetic origin that is added to a soil to supply one or more plant nutrients essential to the growth of plants. A recent assessment found that about 40 to 60% of crop yields are attributable to commercial fertilizer use...
s, rock-wool insulation, glass, and pharmaceutical products. However, oil shale use for production of these items remains small or only in its experimental stages. Some oil shales yield sulfur
Sulfur
Sulfur or sulphur is the chemical element with atomic number 16. In the periodic table it is represented by the symbol S. It is an abundant, multivalent non-metal. Under normal conditions, sulfur atoms form cyclic octatomic molecules with chemical formula S8. Elemental sulfur is a bright yellow...
, ammonia
Ammonia
Ammonia is a compound of nitrogen and hydrogen with the formula . It is a colourless gas with a characteristic pungent odour. Ammonia contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to food and fertilizers. Ammonia, either directly or...
, alumina, soda ash, uranium, and nahcolite
Nahcolite
Nahcolite is a soft, colourless or white carbonate mineral with the composition of sodium bicarbonate also called thermokalite. It crystallizes in the monoclinic system....
as shale-oil extraction byproducts. Between 1946 and 1952, a marine type of Dictyonema
Basidiolichen
Basidiolichens are lichenized members of the Basidiomycota, a much smaller group of lichens than the far more common ascolichens in the Ascomycota. In arctic, alpine, and temperate forests, the most common basidiolichens are in the agaric genus Lichenomphalia and the clavarioid genus Multiclavula...
shale served for uranium
Uranium
Uranium is a silvery-white metallic chemical element in the actinide series of the periodic table, with atomic number 92. It is assigned the chemical symbol U. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons...
production in Sillamäe
Sillamäe
Sillamäe is a town in Ida-Viru County in the northern part of Estonia, on the southern coast of the Gulf of Finland. It has a population of 16,183 and covers an area of 10.54 km²...
, Estonia, and between 1950 and 1989 Sweden used alum
Alum
Alum is both a specific chemical compound and a class of chemical compounds. The specific compound is the hydrated potassium aluminium sulfate with the formula KAl2.12H2O. The wider class of compounds known as alums have the related empirical formula, AB2.12H2O.-Chemical properties:Alums are...
shale for the same purposes. Oil shale gas has served as a substitute for natural gas
Natural gas
Natural gas is a naturally occurring gas mixture consisting primarily of methane, typically with 0–20% higher hydrocarbons . It is found associated with other hydrocarbon fuel, in coal beds, as methane clathrates, and is an important fuel source and a major feedstock for fertilizers.Most natural...
, but , producing oil shale gas as a natural-gas substitute remained economically infeasible.
The shale oil derived from oil shale does not directly substitute for crude oil in all applications. It may contain higher concentrations of olefins, oxygen
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
, and nitrogen
Nitrogen
Nitrogen is a chemical element that has the symbol N, atomic number of 7 and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless, and mostly inert diatomic gas at standard conditions, constituting 78.08% by volume of Earth's atmosphere...
than conventional crude oil. Some shale oils may have higher sulfur or arsenic content. By comparison with West Texas Intermediate
West Texas Intermediate
West Texas Intermediate , also known as Texas light sweet, is a grade of crude oil used as a benchmark in oil pricing. It is a light and sweet crude oil...
, the benchmark standard for crude oil in the futures-contract
Futures contract
In finance, a futures contract is a standardized contract between two parties to exchange a specified asset of standardized quantity and quality for a price agreed today with delivery occurring at a specified future date, the delivery date. The contracts are traded on a futures exchange...
market, the Green River shale oil sulfur
Sulfur
Sulfur or sulphur is the chemical element with atomic number 16. In the periodic table it is represented by the symbol S. It is an abundant, multivalent non-metal. Under normal conditions, sulfur atoms form cyclic octatomic molecules with chemical formula S8. Elemental sulfur is a bright yellow...
content ranges from near 0% to 4.9% (in average 0.76%), where West Texas Intermediate's sulfur content has a maximum of 0.42%. The sulfur content in shale oil from Jordan's oil shales may rise even up to 9.5%.
The arsenic content, for example, becomes an issue for Green River formation oil shale. The higher concentrations of these materials means that the oil must undergo considerable upgrading (hydrotreating
Hydrodesulfurization
Hydrodesulfurization is a catalytic chemical process widely used to remove sulfur from natural gas and from refined petroleum products such as gasoline or petrol, jet fuel, kerosene, diesel fuel, and fuel oils...
) before serving as oil-refinery
Oil refinery
An oil refinery or petroleum refinery is an industrial process plant where crude oil is processed and refined into more useful petroleum products, such as gasoline, diesel fuel, asphalt base, heating oil, kerosene, and liquefied petroleum gas...
feedstock.
Above-ground retorting processes tended to yield a lower API gravity
API gravity
The American Petroleum Institute gravity, or API gravity, is a measure of how heavy or light a petroleum liquid is compared to water. If its API gravity is greater than 10, it is lighter and floats on water; if less than 10, it is heavier and sinks...
shale oil than the in situ processes. Shale oil serves best for producing middle-distillates
Distillation
Distillation is a method of separating mixtures based on differences in volatilities of components in a boiling liquid mixture. Distillation is a unit operation, or a physical separation process, and not a chemical reaction....
such as kerosene
Kerosene
Kerosene, sometimes spelled kerosine in scientific and industrial usage, also known as paraffin or paraffin oil in the United Kingdom, Hong Kong, Ireland and South Africa, is a combustible hydrocarbon liquid. The name is derived from Greek keros...
, jet fuel
Jet fuel
Jet fuel is a type of aviation fuel designed for use in aircraft powered by gas-turbine engines. It is clear to straw-colored in appearance. The most commonly used fuels for commercial aviation are Jet A and Jet A-1 which are produced to a standardized international specification...
, and diesel fuel. Worldwide demand for these middle distillates, particularly for diesel fuels, increased rapidly in the 1990s and 2000s. However, appropriate refining processes equivalent to hydrocracking can transform shale oil into a lighter-range hydrocarbon (gasoline
Gasoline
Gasoline , or petrol , is a toxic, translucent, petroleum-derived liquid that is primarily used as a fuel in internal combustion engines. It consists mostly of organic compounds obtained by the fractional distillation of petroleum, enhanced with a variety of additives. Some gasolines also contain...
).
Economics
Retort
In a chemistry laboratory, a retort is a glassware device used for distillation or dry distillation of substances. It consists of a spherical vessel with a long downward-pointing neck. The liquid to be distilled is placed in the vessel and heated...
, upgrading plant
Upgrader
An upgrader is a facility that upgrades bitumen into synthetic crude oil. Upgrader plants are typically located close to oil sands production, for example, the Athabasca oil sands in Alberta, Canada or the Orinoco tar sands in Venezuela....
, supporting utilities, and spent shale reclamation), would range between US$70–95 ($440–600/m3, adjusted to 2005 values). This estimate considers varying levels of kerogen quality and extraction efficiency. In order to run a profitable operation, the price of crude oil would need to remain above these levels. The analysis also discusses the expectation that processing costs would drop after the establishment of the complex. The hypothetical unit would see a cost reduction of 35–70% after producing its first 500 Moilbbl. Assuming an increase in output of 25 koilbbl/d during each year after the start of commercial production, RAND predicts the costs would decline to $35–48 per barrel ($220–300/m3) within 12 years. After achieving the milestone of 1 Goilbbl, its costs would decline further to $30–40 per barrel ($190–250/m3).
Some commentators compare the proposed American oil-shale industry to the Athabasca oil-sands
Athabasca Oil Sands
The Athabasca oil sands are large deposits of bitumen, or extremely heavy crude oil, located in northeastern Alberta, Canada - roughly centred on the boomtown of Fort McMurray...
industry (the latter enterprise generated over 1 Moilbbl of oil per day in late 2007), stating that "the first-generation facility is the hardest, both technically and economically".
Royal Dutch Shell
Royal Dutch Shell
Royal Dutch Shell plc , commonly known as Shell, is a global oil and gas company headquartered in The Hague, Netherlands and with its registered office in London, United Kingdom. It is the fifth-largest company in the world according to a composite measure by Forbes magazine and one of the six...
has announced that its in situ extraction technology in Colorado could become competitive at prices over $30 per barrel ($190/m3), while other technologies at full-scale production assert profitability at oil prices even lower than $20 per barrel ($130/m3).
To increase efficiency when retorting oil shale, researchers have proposed and tested several co-pyrolysis processes.
A 1972 publication in the journal Pétrole Informations compared shale-based oil production unfavorably with the coal liquefaction
Coal liquefaction
-Methods:The liquefaction processes are classified as direct conversion to liquids processes and indirect conversion to liquids processeses. Direct processes are carbonization and hydrogenation.-Pyrolysis and carbonization processes:...
. The article portrayed coal liquefaction as less expensive, generating more oil, and creating fewer environmental impacts than extraction from oil shale. It cited a conversion ration of 650 litre of oil per one ton
Ton
The ton is a unit of measure. It has a long history and has acquired a number of meanings and uses over the years. It is used principally as a unit of weight, and as a unit of volume. It can also be used as a measure of energy, for truck classification, or as a colloquial term.It is derived from...
of coal, as against 150 litre of shale oil per one ton of oil shale.
A critical measure of the viability of oil shale as an energy source lies in the ratio of the energy produced by the shale to the energy used in its mining and processing, a ratio known as "Energy Returned on Energy Invested" (EROEI
EROEI
In physics, energy economics and ecological energetics, energy returned on energy invested ; or energy return on investment , is the ratio of the amount of usable energy acquired from a particular energy resource to the amount of energy expended to obtain that energy resource...
). A 1984 study estimated the EROEI of the various known oil-shale deposits as varying between 0.7–13.3
although known oil-shale extraction development projects assert an EROEI between 3 to 10. Royal Dutch Shell has reported an EROEI of three to four on its in situ development, Mahogany Research Project
Mahogany Research Project
The Shell's in situ conversion process is an in situ shale oil extraction technology to convert kerogen in oil shale to shale oil. It is developed by the Shell Oil Company.-History:...
.
The water needed in the oil shale retorting process offers an additional economic consideration: this may pose a problem in areas with water scarcity.
Environmental considerations
Mining oil shale involves a number of environmental impacts, more pronounced in surface mining than in underground mining. They include acid drainage induced by the sudden rapid exposure and subsequent oxidation of formerly buried materials, the introduction of metals including mercuryMercury (element)
Mercury is a chemical element with the symbol Hg and atomic number 80. It is also known as quicksilver or hydrargyrum...
into surface-water and groundwater, increased erosion
Erosion
Erosion is when materials are removed from the surface and changed into something else. It only works by hydraulic actions and transport of solids in the natural environment, and leads to the deposition of these materials elsewhere...
, sulfur-gas emissions, and air pollution caused by the production of particulates
Particulates
Particulates – also known as particulate matter , suspended particulate matter , fine particles, and soot – are tiny subdivisions of solid matter suspended in a gas or liquid. In contrast, aerosol refers to particles and/or liquid droplets and the gas together. Sources of particulate matter can be...
during processing, transport, and support activities. In 2002, about 97% of air pollution, 86% of total waste and 23% of water pollution in Estonia came from the power industry, which uses oil shale as the main resource for its power production.
Oil-shale extraction can damage the biological and recreational value of land and the ecosystem in the mining area. Combustion and thermal processing generate waste material. In addition, the atmospheric emissions from oil shale processing and combustion include carbon dioxide
Carbon dioxide
Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...
, a greenhouse gas
Greenhouse gas
A greenhouse gas is a gas in an atmosphere that absorbs and emits radiation within the thermal infrared range. This process is the fundamental cause of the greenhouse effect. The primary greenhouse gases in the Earth's atmosphere are water vapor, carbon dioxide, methane, nitrous oxide, and ozone...
. Environmentalists oppose production and usage of oil shale, as it creates even more greenhouse gases than conventional fossil fuels.
Section 526 of the Energy Independence And Security Act prohibits United States government agencies from buying oil produced by processes that produce more greenhouse gas emissions than would traditional petroleum.
Experimental in situ conversion processes and carbon capture and storage
Carbon capture and storage
Carbon capture and storage , alternatively referred to as carbon capture and sequestration, is a technology to prevent large quantities of from being released into the atmosphere from the use of fossil fuel in power generation and other industries. It is often regarded as a means of mitigating...
technologies may reduce some of these concerns in the future, but at the same time they may cause other problems, including groundwater
Groundwater
Groundwater is water located beneath the ground surface in soil pore spaces and in the fractures of rock formations. A unit of rock or an unconsolidated deposit is called an aquifer when it can yield a usable quantity of water. The depth at which soil pore spaces or fractures and voids in rock...
pollution. Among the water contaminants commonly associated with oil shale processing are oxygen and nitrogen heterocyclic hydrocarbons. Commonly detected examples include quinoline
Quinoline
Quinoline is a heterocyclic aromatic organic compound. It has the formula C9H7N and is a colourless hygroscopic liquid with a strong odour. Aged samples, if exposed to light, become yellow and later brown...
derivatives, pyridine
Pyridine
Pyridine is a basic heterocyclic organic compound with the chemical formula C5H5N. It is structurally related to benzene, with one C-H group replaced by a nitrogen atom...
, and various alkyl homologues of pyridine (picoline
Picoline
Picoline refers to three different methylpyridine isomers, all with the chemical formula C6H7N and a molar mass of 93.13 g mol−1. All three are colourless liquids at room temperature and pressure and are miscible with water and most organic solvents...
, lutidine).
Some commentators have expressed concerns over the oil shale industry's use of water. In 2002, the oil shale-fired power industry used 91% of the water consumed in Estonia. Depending on technology, above-ground retorting uses between one and five barrels of water per barrel of produced shale-oil. A 2008 programmatic environmental impact statement
Environmental impact statement
An environmental impact statement , under United States environmental law, is a document required by the National Environmental Policy Act for certain actions "significantly affecting the quality of the human environment". An EIS is a tool for decision making...
issued by the US Bureau of Land Management
Bureau of Land Management
The Bureau of Land Management is an agency within the United States Department of the Interior which administers America's public lands, totaling approximately , or one-eighth of the landmass of the country. The BLM also manages of subsurface mineral estate underlying federal, state and private...
stated that surface mining and retort operations produce 2 gallon of waste water per 1 short ton (0.892854426455391 LT) of processed oil shale. In situ processing, according to one estimate, uses about one-tenth as much water.
Water concerns become particularly sensitive issues in arid regions, such as the western US and Israel's Negev Desert
Negev
The Negev is a desert and semidesert region of southern Israel. The Arabs, including the native Bedouin population of the region, refer to the desert as al-Naqab. The origin of the word Neghebh is from the Hebrew root denoting 'dry'...
, where plans exist to expand oil-shale extraction despite a water shortage.
Environmental
Environmentalism
Environmentalism is a broad philosophy, ideology and social movement regarding concerns for environmental conservation and improvement of the health of the environment, particularly as the measure for this health seeks to incorporate the concerns of non-human elements...
activists, including members of Greenpeace
Greenpeace
Greenpeace is a non-governmental environmental organization with offices in over forty countries and with an international coordinating body in Amsterdam, The Netherlands...
, have organized strong protests against the oil shale industry. In one result, Queensland Energy Resources
Queensland Energy Resources
Queensland Energy Resources Limited is an Australian oil shale mining and shale oil extraction company with the headquarter in Brisbane. It is the developer of the Stuart and McFarlane oil shale projects.-History:...
put the proposed Stuart Oil Shale Project
Stuart Oil Shale Project
The Stuart Oil Shale Project was an oil shale development project in Australia near Gladstone, Queensland. It was Australia's first major attempt since the 1950s to restart commercial use of oil shale...
in Australia on hold in 2004.
See also
- Core Research CenterCore Research CenterThe Core Research Center is a facility run by the United States Geological Survey, located in "F" bay in building 810 on the Denver Federal Center campus. It is maintained by the USGS to preserve valuable rock cores, well cuttings and various other geologic samples for use by scientists and...
– a United States Geological Survey facility dedicated to preserving valuable rock-samples threatened with disposal or destruction — including oil shales - KukersiteKukersiteKukersite is a marine type oil shale of Ordovician age, found in the Baltic Oil Shale Basin in Estonia and North-West Russia. It was named after Kukruse settlement in Estonia in 1917 by Russian paleontologist Mikhail Zalessky....
– a well-analyzed marine oil shale found in the Baltic Sea basin - Mitigation of peak oilMitigation of peak oilThe mitigation of peak oil is the attempt to delay the date and minimize the social and economic impact of peak oil by reducing the world's consumption and reliance on petroleum. By reducing petroleum consumption, mitigation efforts seek to favorably change the shape of the Hubbert curve, which is...
– discussion of attempts to delay and minimize the impact of "peak oilPeak oilPeak oil is the point in time when the maximum rate of global petroleum extraction is reached, after which the rate of production enters terminal decline. This concept is based on the observed production rates of individual oil wells, projected reserves and the combined production rate of a field...
" (the point in time of maximum global petroleum production), including the development of unconventional oil resources - Narva Power PlantsNarva Power PlantsThe Narva Power Plants are a power generation complex in Narva in Estonia, near the border with Leningrad Oblast, Russia. The complex consists of the world's two largest oil shale-fired thermal power plants, Eesti Power Plant and Balti Power Plant . In 2007, Narva Power Plants generated about...
– the world's largest complex fired by oil shale - Oil reservesOil reservesThe total estimated amount of oil in an oil reservoir, including both producible and non-producible oil, is called oil in place. However, because of reservoir characteristics and limitations in petroleum extraction technologies, only a fraction of this oil can be brought to the surface, and it is...
– discussion of global crude-oil supplies - Tar sandsTar sandsBituminous sands, colloquially known as oil sands or tar sands, are a type of unconventional petroleum deposit. The sands contain naturally occurring mixtures of sand, clay, water, and a dense and extremely viscous form of petroleum technically referred to as bitumen...
- TasmaniteTasmaniteTasmanite is a rock type almost entirely consisting of the prasinophyte alga Tasmanites. It is commonly associated with high-latitude, nutrient-rich, marginal marine settings find in Tasmania. It is classified as marine type oil shale. It is found in many oil-prone source rocks and, when present,...
– a marine oil shale found in Tasmania - TorbaniteTorbaniteTorbanite, also known as boghead coal, is a variety of fine-grained black oil shale. It usually occurs as lenticular masses, often associated with deposits of Permian coals. Torbanite is classified as lacustrine type oil shale....
– a lacustrine oil shale found in Scotland - World energy resources and consumptionWorld energy resources and consumption]World energy consumption in 2010: over 5% growthEnergy markets have combined crisis recovery and strong industry dynamism. Energy consumption in the G20 soared by more than 5% in 2010, after the slight decrease of 2009. This strong increase is the result of two converging trends...
External links
|accessdate=2008-04-22 }}- "This Oven Makes Oil Out Of Rocks" , February 1949, Popular Science primer article with illustrations on basic of the oil shale production process