Shale oil extraction: Difference between revisions

Content deleted Content added

Inline

Revision as of 06:25, 18 November 2007

Oil shale extraction refers to the process in which kerogen, an immature form of hydrocarbon trapped in the oil shale, is converted into a usable hydrocarbon in form of a petroleum-like shale oil—a form of non-conventional oil—and combustible shale gas. It is a process wherein shale is heated in absence of oxygen, to a temperature at which kerogen is decomposed or pyrolysed into gas, condensable oil, and a solid residue. Decomposition begins at relatively low temperatures (300 °C (570 °F)), but proceeds more rapidly and more completely at higher temperature.^[1]

The extraction techniques can be broadly classified into two primary methods, the ex-situ method and the in-situ method. There are hundreds of patents for oil shale retorting technologies.^[2] However, only a few dozen have been tested in a pilot plant (with capacity 1 to 10 tonnes of oil shale per hour) and less than ten technologies have been tested at a demonstration scale (40 to 400 tonnes per hour). Currently, only five technologies are in commercial use, namely Kiviter, Galoter, Fushun, Petrosix, and Alberta Taciuk. Almost all commercial retorts currently in operation or in development stages are internal heating retorts.^[3] Currently, shale oil extraction is being undertaken in Estonia, Brazil and China, while some other countries such as Australia, USA, Canada and Jordan have planned to start or restore shale oil production.^[4]^[5]

Classification of extraction technologies

Depending whether retorting is done above or below ground, the extraction techniques can be broadly classified into two primary methods, the ex-situ method and the in-situ method. In case of ex-situ method, also known as above-ground retorting, the oil shale is mined and transported to the retort facility in order to extract the oil. The in-situ method converts the kerogen while it is still in the form of an oil shale deposit and then it is extracted via a well, where it rises up as normal petroleum.^[6] Based on the method used to heat the shale to retorting temperature, the above mentioned techniques could be further classified into internal combustion, hot recycled solids, conduction through a wall, externally generated hot gas, reactive fluids, and volumetric heating. There are many possible embodiments of these concepts, so the table is representative and not complete. Some processes are difficult to classify according to this scheme due to the unique method of heat input (e.g., ExxonMobil Electrofrac) or due to limited information. ^[6]

**Classification of oil shale processing technologies according to heating method and location**^[6]
Heating Method	Above Ground (ex-situ)	Below Ground (in-situ)
Internal combustion	Kiviter, Fushun, Union A, Paraho Direct, Superior Direct	Oxy MIS, LLNL RISE, Geokinetics Horizontal, Rio Blanco
Hot recycled solids (inert or burned shale)	Alberta Taciuk, Galoter, Lurgi, TOSCO II, Chevron STB, LLNL HRS, Shell Spher	-
Conduction through a wall (various fuels)	Pumpherston, Hom Tov, Fischer assay, Oil-Tech, EcoShale In-Capsule Process, Combustion Resources	Shell ICP (primary method), EGL Oil Shale Process, IEP Geothermic Fuel Cell Process
Externally generated hot gas	PetroSIX, Union B, Paraho Indirect, Superior Indirect, Syntec process (Smith process)	Chevron CRUSH, Petro Probe
Reactive fluids	IGT Hytort (high-pressure H2), Xtract Technology (supercritical solvent extraction), Donor solvent processes, Chattanooga fluid bed reactor	Shell ICP (some embodiments)
Volumetric heating	-	ITTRI, LLNL and Raytheon radiofrequency processes, Global Resource microwave process, Electro-Petroleum EEOP

Ex-situ technologies

File:Stuart oil shale processing plant.jpg

Stuart oil shale pilot plant

In case of the ex-situ method, the oil shale is mined either by underground mining or surface mining from the ground and then transported to a processing facility. At the facility, the oil shale is usually heated to 450 °C to 500 °C (840 °F to 930 °F) at which, the kerogen in the oil shale decomposes to gas, oil vapor and char, a process known as retorting. The gas and oil vapors are separated from the spent shale and cooled, causing the oil to condense. The oil may be used as a fuel oil or upgraded to meet refinery feed specifications by adding hydrogen and removing impurities such as sulfur and nitrogen. The non-condensible retort gas and char may be burnt and the heat energy may be reused for heating the raw shale or generating electricity.

Based on the size of feed oil shale, the ex-situ technologies can be classified into lump shale using technologies and particulate shale using technologies. In general, the lump shale is used in internal hot gas carrier technologies, while the particulate oil shale (less than 10 millimetres (0.4 in)) is used in internal hot solid carrier technologies.^[3]

Internal combustion technologies

Internal combustion technologies use heat transferred by flowing gases, which are generated by combustion within the retort. Common characteristics of these technologies are, feed shale consisting of lumps which range from 10 to 100 millimetres (0.4 to 4 in) in diameter, and the retort vapors are diluted with the exhaust generated by the combustion. The main technologies are Kiviter, Union A, Paraho Direct, Superior Direct, and Fushun processes.^[6]^[7] The Kiviter processing takes place in gravitational shaft retorts and it is possible by using only large-particle feed. The process gas combustion products are used as the heat carrier. In the case of kukersite, the yield of oil accounts for 14-17 % of shale and the oil consists of a small amount of low-boiling fractions. Main problems associated with Kiviter process are environmental concerns such as extensive use and pollution of water in the process, as also the waste solid residue which continues to leach toxic substances.^[8]^[9] The Kiviter process is used by Estonian company VKG Oil, a subsidiary of Viru Keemia Grupp.^[10] The company operates several retorts, the largest one, having a capacity of processing 40 tonnes per hour of oil shale.

Like the Kiviter, the Fushun-type retort processes oil shale lumps in a vertical shaft kiln. The Fushun Mining Group in Liaoning Province, China operates the largest shale oil plant in the world. In 2003, it employed 80 Fushun-type retortsand as of 2007 it has increased to 180 retorts. Each retort processes about 4 tonnes per hour of shale.^[11]

The Paraho Direct is an American version of the lump-processing vertical shaft kiln. This technology is used by Shale Technologies LLC in a pilot plant facility in Rifle, Colorado.^[12]

Hot recycled solids technologies

Hot recycled solids technologies use heat, which is transferred by mixing hot solid particles with the oil shale. These technologies usually process oil shale fine particles (less than 10 mm). The heat carrier (usually shale ash) is heated in a separate chamber or vessel, thus the retort vapors are not diluted with combustion exhaust. The main technologies in this category include Alberta Taciuk Process (ATP), Galoter, TOSCO II, Lurgi-Ruhrgas, Chevron STB, LLNL HRS, and Shell Spher processes.^[6]^[7]

In the Galoter process, retorting takes place in a rotary kiln-type retort using fine particles. The spent shale is burnt in a spouted bed and solid shale ash is used as the heat carrier.^[9] In case of kukersite, the yield of crude oil accounts for roughly 12 % of shale and the oil consists 15-20 % of low-boiling fractions. The Galoter process is more eco-friendly than the Kiviter process, as the use of water and pollution caused is minimal. However, the burning residue does cause some environmental problems due to organic carbon and calcium sulphide content.^[8] The Galoter process is used for oil production by Eesti Energia, an Estonian energy company.^[10] The company has two retorts, both processing 125 tonnes per hour of oil shale and plans are underway to build two more.^[13] In 2008, another Estonian company, VKG Oil AS, is going to construct a new production line using the Galoter process engineered by Atomenergoproject of St Petersburg.^[14]

File:ATP.PNG

Alberta Taciuk Processor (ATP) retort

Similar to the Galoter process, the Alberta Taciuk processes oil shale fine particles in a rotary kiln-type retort. The unique feature of the Alberta Taciuk process is that drying and pyrolysis of the feed shale and the combustion, recycling and cooling of spent shale, all occur in a single multi-chamber horizontal, rotating vessel.^[15]^[16] The extracted oil consists up to 30 % of low-boiling fractions. The water pollution caused by the process is quite limited.^[8] Australian oil companies Southern Pacific Petroleum NL and later Queensland Energy Resources operated a 250 tonnes per hour industrial-scale pilot plant using the Alberta Taciuk Processor. The plant was shut down in 2004. UMATAC Industrial Processes is currently designing a 250 tonnes per hour Alberta Taciuk Processor in China, and is scheduled to start operation in 2008.^[17] Estonian VKG Oil is considering construction of a new retort facility using the Alberta Taciuk Processor.^[10] Oil shale exploration company LLC has arranged for an exclusive right to license the ATP for research, development and demonstration near Vernal, Utah.^[18]

As with the Galoter and Alberta Taciuk process, the TOSCO II also processes oil shale fine particles which are heated with hot recycled solids in a rotary kiln. However, instead of recycling shale ash, the TOSCO II circulates hot ceramic balls between the retort and a heater. The process was tested in a 40 tonnes per hour test facility near Parachute Colorado which was shut down in 1972. The LLNL HRS (hot-recycled-solid) retorting process was developed by the Lawrence Livermore National Laboratory. The technology was used in a 4 tonnes per day pilot plant from 1990 to 1993. A delayed-fall combustor, which is used in this process, gives greater control over the combustion process as compared to a lift pipe combustor. A fluidized-bed mixer is used instead of the screw mixer, which is used in the Lurgi process. The majority of the pyrolysis occurs in a settling-bed unit.^[6]

Conduction through a wall technologies

Conduction through a wall technologies use heat, which is transferred by conduction through the retort wall. These technologies normally process fine particles and the retort vapors are not diluted by combustion exhaust. Technologies include Pumpherston, Fischer assay, Hom Tov and Oil-Tech processes.^[6]^[7] Oil-Tech staged electrically heated retort process is developed by Millennium Synfuels, LLC (former Oil Tech Inc.). In this process, the feed oil shale is heated to greater temperatures as it goes further down the retort. The retort-style prototype was reported to have passed a test.^[19]

In the Hom Tov process (US Patent 5372708), oil shale fine particles are slurried with waste bitumen and pumped through coils in a heater. Israeli promoters of this process claim that the technology enables the shale to be processed at somewhat lower temperatures with the addition of the catalyzing bitumen. The technology has not been tested in a pilot plant yet.^[20] Fischer Assay is a standardized laboratory test that is used to measure the grade of an oil shale sample. A 100 gram sample crushed to 8 mesh (2.38 mm) screen is heated in a small aluminum retort to 500 °C (930 °F) at a rate of 12 °C (54 °F) per minute, and held at that temperature for 40 minutes.^[21] The distilled vapors of oil, gas, and water are passed through a condenser and cooled with ice water into a graduated centrifuge tube. The oil yields achieved by other technologies are often reported as a percentage of the Fischer Assay oil yield.

In Red-Leaf Resources EcoShale In-Capsule Process, hot gas generated by natural gas or pyrolysis gas is circulated through an oil shale rubble pile using a set of parallel pipes. The heat is transferred to the shale through the pipe walls rather than being injected directly into the rubble pile, thereby avoiding dilution of the pyrolysis gas with the heating gas. The rubble pile is encapsulated by a low-cost earthen impoundment structure designed to prevent environmental contamination and to provide easy reclamation. Energy efficiency is enhanced by recovering heat from the spent shale by passing cool gas through the heating pipes and then using it to preheat adjacent capsules.^[22]^[23]

A new process from Combustion Processes, Inc., seeks to eliminate carbon dioxide emissions from the shale oil production process. Pyrolysis occurs in a rotating kiln heated by hot gas flowing through an outer annulus. The hot gas is created by burning hydrogen generated in a separate unit by coal gasification followed by carbon dioxide separation. The annular geometry achieves heat transfer to the moving shale through a wall, thereby avoiding dilution of the product gas.^[24]

Externally generated hot gas technologies

Externally generated hot gas technologies or indirectly heated technologies use heat, transferred by gases which are heated outside the retort vessel. The main technologies are Petrosix, Union B, Paraho Indirect, and Superior Indirect processes.^[6]^[7] As with the the internal combustion technologies, most of the externally-generated hot gas technologies process oil shale lumps in vertical shaft kilns; however, the retort vapors are not diluted with combustion exhaust. The world’s largest operational surface oil shale pyrolysis reactor is the Petrosix which is located in São Mateus do Sul, Paraná, Brazil. The 11 metres (36 ft) diameter vertical shaft kiln is owned by Petrobras and has being operating since 1992 with high availability. The company operates two retorts, the largest of which processes 260 tonnes per hour of oil shale.^[10]^[25] The largest retort ever built used the Union B technology, developed by Unocal. The Union B processed 400 tonnes per hour of oil shale lumps heated by externally generated hot gas. However, unlike all other vertical shaft kilns, the Union B pumped the oil shale into the bottom of the retort, with the hot gas entering at the top. Unocal operated the retort from 1986 to 1992 near Parachute, Colorado. The Paraho Indirect technology is similar to the Petrosix which is considered a highly reliable technology for use with U.S. oil shale.^[10]

Two companies, Syntec Energy and Western Energy Partners, have proposed new hot gas processes based on linking coal gasification with rotating kiln retorts. The hot, hydrogen-rich synthesis gas from the coal gasifier is fed into the rotating kiln in direct contact with the oil shale, thereby heating it to pyrolysis temperature. The effluent synthesis gas is then used to generate electric power or other products typical of syngas processes.^[22]

Reactive fluids technologies

Reactive fluids technologies are IGT Hytort (high-pressure H2) process, Xtract Technology (supercritical solvent extraction), Donor solvent processes, and Chattanooga fluid bed reactor.^[6]^[26]^[22] In the IGT Hytort process, developed by the Institute of Gas Technology (IGT), oil shales are processed at controlled heating rates in an atmosphere of hydrogen at high pressure.^[27] This technology like other reactive fluid technologies, is more appropriate for oil shales with low hydrogen content, such as the Eastern US Devonian shales, for which only a third of the organic carbon is typically converted to oil during conventional overground retorting. The hydrogen or hydrogen donor react with coke precursors and roughly double the yield of oil, depending on the characteristics of the shale and process.^[28]

Chattanooga Corp. has developed an extraction process which uses a fluid bed reactor and an associated hydrogen fired heater. In this process conversion reaction occurs at relatively low temperatures (1,000 °F (540 °C)) through thermal cracking and hydrogenation into hydrocarbon vapors and spent solids. The thermal cracking allows for hydrocarbon vapors to be extracted off the oil shale which is then extracted and scrubbed of solids. The vapor is then cooled, during which condensate drops out of the gas and the remaining hydrogen, light hydrocarbon and acid gases are passed through an amine scrubbing system to remove hydrogen sulfide which is converted to elemental sulfur. The cleaned hydrogen and light hydrocarbon gases are then fed back into the system for compression or into the hydrogen heater which provides the heat for the fluid bed reactor. This nearly-closed-loop allows for an efficient process where nearly all the energy needs are provided by the source material. The demonstration plant in Alberta was able to produce 930 barrels (~130 t) of oil per kilotonne of oil shale at an API gravity ranging between 28 to 30. With hydrotreating, it would be possible to improve this to 38-40 °API. Chattanooga Corp is currently looking at a design to produce a 2,500 barrels (~330 t) per hour facility.^[22]

In-situ technologies

In in-situ processing technologies, the oil shale is heated underground. Potentially these technologies are able to extract more oil from a given area of land than conventional ex-situ processing technologies, as the wells can reach greater depths than surface strip-mines.^[29] Several companies have patented methods for in-situ retorting. However, most of these methods are still in experimental stages.

The in-situ technologies are usually classified as true in-situ processes (TIS) and modified in-situ processes (MIS). True in-situ processes do not involve mining the oil shale. The modified in-situ processes involve drilling and fracturing the target deposit above the mined area to create a void space of 20-25 % which improves the flow of gases and liquid fluids through the rock formation, thereby increasing the volumes and quality of the oil produced.^[10]

Early in-situ processes

A variety of true in-situ processes were tried prior to the oil shale crash in the 1980s. Most notable are the Equity Oil process, which injected superheated steam in the permeable leached zone of Colorado’s Piceance Basin,^[30] and the Geokinetics Process, which is a horizontal combustion retort in which permeability is formed by explosive uplift and rubblization (the generation of rubble consisting of various sized fragments).^[31]^[32] Little yield information is available from the Equity process, but the Geokinetics process generally recovered 40-50 % of the Fischer Assay oil.^[31]

Variations of the modified in-situ (MIS) process have been investigated by the US Bureau of Mines, Lawrence Livermore National Laboratory, Occidental Petroleum, Rio Blanco Corporation, and Multi-Mineral Corporation. An early concept in the 1960s was to create a rubble chimney using a nuclear explosive.^[33] However, this approach was abandoned for a variety of technical reasons. Subsequently, a variety of conventional mining and rubblization approaches were explored. The first MIS oil shale experiment was conducted by Occidental Petroleum in 1972 at Logan Wash.^[10] Oil yield was adversely affected by inefficient sweep of the rubblized zone due to non-uniform permeability.^[34] A subsequent series of field experiments aimed at improving permeability uniformity were carried out by using different mining and blasting techniques. Depending on different types of calculation used, Occidental achieved 50-60 % Fischer Assay oil yield in Retorts 7 and 8.^[34] Rio Blanco Corporation used a different mining and blasting approach which created a bed with close to 40 % porosity. This enabled them to retort the chimney at a substantially faster rate and achieve higher oil yields around 70% of Fischer assay.^[31] Multi-Mineral Corporation proposed a more complicated MIS process for Saline Zone oil shale which included recovery of nahcolite and Dawsonite minerals.^[35]

Modern in-situ processes

There has been a recent resurgence of interest in in-situ recovery processes. In contrast to the 1980s emphasis on combustion retorting of subsurface rubble, current study focuses on true in-situ processes, i.e. processes in which no shale removal or explosive uplift is used to create permeability. The processes can be separated by whether they inject hot fluids into the formation (Chevron CRUSH and Petro Probe) or use line or plane heating sources following by thermal conduction and convection to distribute heat through the formation (Shell ICP, EGL Resources, ExxonMobil Electrofrac). All but the Chevron CRUSH process are expected to produce a ~40 API gravity shale oil with fewer olefins and polar molecules due to in-situ oil coking and cracking.

Shell's in-situ conversion process (ICP)

File:Shell Freeze Wall Oil Shae.PNG

Shells Freeze Wall for in-situ shale oil production

Since 2000, the Shell Oil Company has been developing a new in-situ method under the Mahogany Research Project in Colorado, 200 miles (320 km) west of Denver. Though this method is energy intensive, it compares well to other heavy oil projects such as the tar sands. At full scale, it is estimated that for every unit of energy consumed, 3.5 units would be produced over the project life cycle.^[36] A freeze wall is first constructed to isolate the region to be retorted from surrounding groundwater. 2,000 feet (610 m) wells, eight feet apart, are drilled and circulated with a super-chilled liquid to cool the ground to −60 °F (−50 °C). Water is then removed from the working zone. Heating and recovery wells are drilled on 40 feet (12 m) spacing within the working zone. Electrical heating elements are lowered into the heating wells and used to heat the kerogen to 650 °F (340 °C) to 700 °F (370 °C) over a period of approximately four years, slowly converting it into oil and gases, which are then pumped to the surface. Shell believes that it will be possible to recover around 65-70 % of the hydrocarbons by this technique. An operation producing 100,000 barrels a day would require a dedicated power generating capacity of 1.2 gigawatts. To maximize the functionality of the freeze walls, working zones will be developed, adjacent to each other in succession. This in-situ method requires 100 % surface disturbance, greatly increasing the footprint of extraction operations in comparison to conventional oil and gas drilling. The current test sites are expected to produce in the region of 600 barrels (~84 t) to 1,500 barrels (~210 t) per day.^[36] Biggest challenges of the ICP technology are an extensive water use and a possible risk of groundwater pollution.^[37]

EGL Oil Shale Process

EGL Resources proposes a method which combines horizontal wells, through which steam is passed, and vertical wells, which provide both vertical heat transfer through refluxing of generated oil and a means to collect and produce the oil. In contrast to the Equity process, the steam circulates through a closed loop, and no fluids are injected into the formation. Horizontal heat transfer from the vertical wells is similar to that in the Shell ICP, and a similar quality of oil is expected. They are currently leasing a 160 acres (650,000 m²) tract in the Piceance Basin from the US Bureau of Land Management for their tests.^[38]

Chevron CRUSH process

Chevron Corporation and Los Alamos National Laboratory formed a joint research project in 2006 to develop oil shale extraction technology named Chevron CRUSH process. They are investigating whether carbon dioxide can be injected into the formation at a raised temperature which will decompose the kerogen into conventional hydrocarbons. The carbon dioxide would be injected via conventionally drilled wells and then exposed to the formation via a series of horizontal fractures where it would circulate around. The hydrocarbons would then be produced via conventional vertical oil wells. This method is based upon research and trials carried out in the 1950s by Sinclair Oil and Gas company which developed a method using natural and induced fractures between vertical wells to produce the in-situ kerogen. Continental Oil (now ConocoPhillips) and the University of Akron also demonstrated and were issued patents which showed that carbon dioxide was a good carrier gas which helped recover the shale oil.^[39]

Petro Probe

Petro Probe, a subsidiary of Earth Science Search have listed a process which involves injecting super-heated air into wells drilled into the oil shale. The process involves injecting air which is super-heated at the surface, into wells drilled into the oil shale. The super-heated air then mixes and melts the in-situ shale oil which is transported back to the surface in the form of gas which is then cooled and the condensate is collected. The remnant gas is then re-used to heat the air and is injected back with other waste products into the formation thereby minimizing the environmental impact.^[22]

ExxonMobil Electrofrac

ExxonMobil has been involved in oil shale development since the 1960s and is currently focusing on in-situ developments. They are concentrating on an in-situ method which heats the oil shale via an electrically conductive heating fluid injected into the reservoir which heats the oil shale via a series of hydraulic fractures. The oil shale is produced by separate dedicated production wells. It is thought that the most likely method is to have horizontal wells which have been hydraulically fractured along the vertical axis. These wells are placed in a parallel row with a second horizontal well intersecting them at their toe. This will allow the two different charges to be applied at either end. ExxonMobil is pursuing this method as they believe it provides a better method, which is to surround the oil shale and heat it up. The Electrofrac method has been tested in laboratories and test sites are now currently being considered for a field trial.^[22]

Volumetric heating by radiowave, microwave, and direct current technologies

The concept of volumetric heating by radio waves (radio frequency processing) of oil shale was developed at Illinois Institute of Technology in the late 1970s. The concept was to heat modest volumes of shale, using vertical electrode arrays. Deeper large volumes could be processed at slower heating rates over a period of time. The technology was developed later by the Lawrence Livermore National Laboratory (LLNL), and by several other inventors. The LLNL concept was based on the use of wells spaced at tens of meters to heat vast expanse of deep oil shale very slowly. The concept presumed a radio frequency at which the skin depth is many tens of meters, and thereby overcoming the thermal diffusion times needed for conductive heating.^[6]^[40] The microwave heating technology uses same principle as radio wave heating, although it is believed that radio wave heating technology is an advancement over microwave heating technology because the energy can penetrate farther into the formation.^[41] The radio frequency processing technology is currently being tested by Raytheon Corporation, while Global Resource Corp. is still carrying on microwave heating tests.^[41] Electro-Petroleum proposes electrically enhanced oil production (EEOP) by heating oil shale and generating shale oil by using direct current between cathodes in producing wells and anodes either at the surface or at depth in other wells. Passage of the current through the formation results in resistive Joule heating. This process has improved production from heavy oil fields in short term tests.^[22]^[42]

Economics

The various attempts to extract oil from oil shale, over a period of over 150 years, have experienced successes when the cost of shale oil production in a given region was less than the price of crude oil or its other substitutes.^[43] According to a survey conducted by the RAND Corporation, a surface retorting complex (comprising a mine, retorting plant, upgrading plant, supporting utilities, and spent shale reclamation) is unlikely to be profitable in the United States until crude oil prices range between US$70 to US$95 per barrel (in 2005 dollars).^[44] Once commercial plants are in operation and experience-based learning takes place, costs are expected to decline in 12 years to US$35–US$48 per barrel. After production of 1,000 million barrels, costs are estimated to decline further to US$30 – US$40 per barrel.^[45] Royal Dutch Shell has announced that its ICP technology could be competitive at prices over US$30 per barrel, while other technologies at full-scale production assert profitability at oil prices even lower than US$20 per barrel.^[46]^[47]^[48]^[10] To increase the efficiency of oil shale extraction, several co-pyrolysis processes have been proposed and tested.^[49]^[50]^[51]^[52]^[53]

A critical measure of the viability of oil shale as an energy source is 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.^[54] Royal Dutch Shell has reported an EROEI of three to four on its in-situ development, Mahogany Research Project.^[36]^[46]^[55] An additional economic consideration is the water needed in the oil shale retorting process, which may pose a problem in areas with water scarcity.

Environmental effects of oil shale extraction

The oil shale industry can have a negative impact on the surrounding environments, if the risks associated with it are not managed correctly. Environmental concerns raised over the extraction of shale oil have caused the oil shale industry in some countries to come to a halt.^[40]^[56] Opposition to the proposed Stuart Oil Shale Project in Australia resulted in its being put on hold in 2004.^[56]^[57]^[58]

Surface-mining of oil shale deposits has the same environmental impacts as those of open-pit mining. In addition, thermal processing generate waste material, and the atmospheric emissions include carbon dioxide, a major greenhouse gas. 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.^[59]

References

^ Koel, Mihkel (1999). "Estonian oil shale". Oil Shale. A Scientific-Technical Journal (Extra). Estonian Academy Publishers. ISSN 0208-189X. Retrieved 2007-07-21.
^ "Process for the recovery of hydrocarbons from oil shale". FreePatentsOnline. Retrieved 2007-11-03.
^ ^a ^b Qian, Jialin; Wang, Jianqiu (2006-11-07). "World oil shale retorting technologies" (PDF). Amman, Jordan. Retrieved 2007-06-29. {{cite journal}}: Check date values in: |date= (help); Cite journal requires |journal= (help)
^ Brendow, K. (2003). "Global oil shale issues and perspectives. Synthesis of the Symposium on Oil Shale. 18-19 November, Tallinn" (PDF). Oil Shale. A Scientific-Technical Journal. 20 (1). Estonian Academy Publishers: 81–92. ISSN 0208-189X. Retrieved 2007-07-21.
^ Hamarneh, Yousef (1998; 2006). "Oil Shale Resources Development In Jordan" (PDF). Amman: Natural Resources Authority of Jordan. Retrieved 2007-06-16. {{cite journal}}: Check date values in: |date= (help); Cite journal requires |journal= (help)
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j Burnham, Alan K.; McConaghy, James R. (2006-10-16). "Comparison of the Acceptability of Various Oil Shale Processes" (PDF). Golden: 26th Oil Shale Symposium. UCRL-CONF-226717. Retrieved 2007-06-23. {{cite journal}}: Check date values in: |date= (help); Cite journal requires |journal= (help)
^ ^a ^b ^c ^d "An Assessment of Oil Shale Technologies" (PDF). June 1980. NTIS order #PB80-210115. Retrieved 2007-11-03. {{cite journal}}: Cite journal requires |journal= (help)
^ ^a ^b ^c Mölder, Leevi (2004). "Estonian Oil Shale Retorting Industry at a Crossroads" (PDF). Oil Shale. A Scientific-Technical Journal. 21 (2). Estonian Academy Publishers: 97–98. ISSN 0208-189X. Retrieved 2007-06-23.
^ ^a ^b Soone, Jüri; Riisalu, Hella; Kekisheva, Ljudmilla; Doilov, Svjatoslav (2006-11-07). "Environmentally sustainable use of energy and chemical potential of oil shale" (PDF). Amman, Jordan. Retrieved 2007-06-29. {{cite journal}}: Check date values in: |date= (help); Cite journal requires |journal= (help)
^ ^a ^b ^c ^d ^e ^f ^g ^h "Strategic Significance of America's Oil Shale Resource. Volume II Oil Shale Resources, Technology and Economics" (PDF). Office of Deputy Assistant Secretary for Petroleum Reserves; Office of Naval Petroleum and Oil Shale Reserves; U.S. Department of Energy. 2004. Retrieved 2007-06-23. {{cite journal}}: Cite journal requires |journal= (help) Cite error: The named reference "fossilenergy" was defined multiple times with different content (see the help page).
^ Purga, Jaanus (2004). "Today's rainbow ends in Fushun" (PDF). Oil Shale. A Scientific-Technical Journal. 21 (4). Estonian Academy Publishers: 269–272. ISSN 0208-189X. Retrieved 2007-06-23.
^ "Shale Technologies". Shale Technologies, LLC. Retrieved 2007-06-24.
^ Liive, Sandor (2007). "Oil Shale Energetics in Estonia" (PDF). Oil Shale. A Scientific-Technical Journal. 24 (1). Estonian Academy Publishers: 1–4. ISSN 0208-189X. Retrieved 2007-06-24.
^ "New shale oil line for VKG Oil AS" (PDF). Rintekno Newsletter. 20. Rintekno Oy. 2006. Retrieved 2007-06-24.
^ "Dry thermal processor. US Patent 5366596". PatentGenius. Retrieved 2007-11-03.
^ "Technology Details: Alberta Taciuk Process". aboutREMEDIATION. Retrieved 2007-06-24.
^ Chandler, Graham (2006). "US eyes Alberta as model for developing oil shale" (PDF). Alberta Oil. 2 (4): 16–18. Retrieved 2007-06-24.
^ "OSEC's Process: A Proven Technology". Oil Shale Exploration Company, LLC. Retrieved 2007-06-24.
^ Fischer, Perry A. (2005). "Hopes for shale oil are revived". World Oil. 226 (8). Retrieved 2007-06-24.
^ Sandler, Neal (2006). "Israel assesses new oil shale technology" (PDF). Energy Economist (297). Platts. Retrieved 2007-11-11.
^ Dyni, John R. (2006). "Geology and resources of some world oil-shale deposits. Scientific Investigations Report 2005–5294" (PDF). U.S. Department of the Interior. U.S. Geological Survey. Retrieved 2007-07-09. {{cite journal}}: Cite journal requires |journal= (help)
^ ^a ^b ^c ^d ^e ^f ^g "Secure Fuels from Domestic Resources: The Continuing Evolution of America's Oil Shale and Tar Sands Industries" (PDF). United States Department of Energy. 2007: 1–68. Retrieved 2007-07-11. {{cite journal}}: Cite journal requires |journal= (help) Cite error: The named reference "DOE" was defined multiple times with different content (see the help page).
^ Patten, James W. (2007). "Red-Leaf Resources. Presentation at the Utah Energy Summit" (PDF). Utah Energy Summit. Retrieved 2007-11-11. {{cite journal}}: Cite journal requires |journal= (help)
^ 27th Oil shale Symposium Proceedings, Colorado School of Mines Press, 2007
^ Laherrère, Jean (2005). "Review on oil shale data" (PDF). Hubbert Peak. Retrieved 2007-06-17. {{cite journal}}: Cite journal requires |journal= (help)
^ "Xtract Ltd". Xtract Energy Plc. 2007. Retrieved 2007-07-28.
^ Weil, S. A.; Feldkirchner, H. L.; Punwani, D. V.; Janka, J. C. (1979-01-01), IGT HYTORT Process for hydrogen retorting of Devonian oil shales, Institute of Gas Technology,Chicago, IL, CONF-790571-3 {{citation}}: Check date values in: |date= (help); Cite has empty unknown parameter: |1= (help)
^ Rex, R.; Janka, J. C.; Knowlton, T. (1984), Cold Flow Model Testing of the Hytort Process Retort Design.17th Oil Shale Symposium, Colorado School of Mines Press, pp. 17–36
^ Ennis, D.L. (2006-08-15). "Oil Shale—An Investment We Can't Afford". California Chronicle. Retrieved 2007-07-26. {{cite journal}}: Check date values in: |date= (help); Cite journal requires |journal= (help)
^ Dougan, P.M.; Dockter, L. (1981), BX In Situ Oil Shale Project. 14th Oil Shale Symposium, Colorado School of Mines Press, pp. 118–127
^ ^a ^b ^c Tyner, C.E.; Parrish, R.L.; Major, B.H.; Lekas, J.M. (1982), Sandia/Geokinetics Retort 23: A Horizontal In Situ Retorting Experiment. 15th Oil shale Symposium Proceedings, Colorado School of Mines Press, pp. 370–384 Cite error: The named reference "sandia" was defined multiple times with different content (see the help page).
^ Costimiris, E.C. (1982), Investigation of the Geokinetics horizontal in-situ oil-shale-retorting process. Annual Report 1981, Geokinetics, Inc
^ Lombard, D.B.; Carpenter, H.C. (1967), "Recovering Oil by Retorting a Nuclear Chimney in Oil Shale", Journal of Petroleum Technology (19), Society of Petroleum Engineers: 727–734
^ ^a ^b Gregg, M.L.; Campbell, J.H. (1980), Sweep efficiency modeling of modified in-situ retorts. 13th Oil shale Symposium Proceedings, Colorado School of Mines Press, pp. 87–100 Cite error: The named reference "gregg" was defined multiple times with different content (see the help page).
^ "Integrated in situ shale oil and mineral recovery process". FreePatentsOnline. 1981-08-25. United States Patent 4285547. Retrieved 2007-11-11. {{cite web}}: Check date values in: |date= (help)
^ ^a ^b ^c "Oil Shale Test Project. Oil Shale Research and Development Project" (PDF). Shell Frontier Oil and Gas Inc. 2006-02-15. Retrieved 2007-06-30. {{cite journal}}: Check date values in: |date= (help); Cite journal requires |journal= (help) Cite error: The named reference "shell" was defined multiple times with different content (see the help page).
^ Jon Birger (2007-11-01). "Oil shale may finally have its moment". Fortune. Retrieved 2007-11-17. {{cite journal}}: Check date values in: |date= (help); Cite journal requires |journal= (help)
^ "Innovation in Shale Technology". EGL Shale. 2006-11-16. Retrieved 2007-07-06. {{cite web}}: Check date values in: |date= (help)
^ "Environmental Assessment, Chevron Oil Shale Research, Development & Demonstration" (PDF). U.S. Department of Interior. 2006. Retrieved 2007-07-06. {{cite journal}}: Cite journal requires |journal= (help)
^ ^a ^b A.K. Burnham (2003-08-20). "Slow Radio-Frequency Processing of Large Oil Shale Volumes to Produce Petroleum-like Shale Oil" (PDF). Lawrence Livermore National Laboratory. UCRL-ID-155045. Retrieved 2007-06-28. {{cite journal}}: Check date values in: |date= (help); Cite journal requires |journal= (help)
^ ^a ^b Megan Harris (2007-07-20). "Oil from shale could meet need". United Press International. Retrieved 2007-08-19. {{cite web}}: Check date values in: |date= (help)
^ "Electrically enhanced oil production using DC technology" (PDF). Electro-Petroleum, Inc. Retrieved 2007-11-11. {{cite journal}}: Cite journal requires |journal= (help)
^ Robert Rapier (2006-06-12). "Oil Shale Development Imminent". R-Squared Energy Blog. Retrieved 2007-06-22. {{cite journal}}: Check date values in: |date= (help); Cite journal requires |journal= (help)
^ Cite error: The named reference rand was invoked but never defined (see the help page).
^ "A study on the EU oil shale industry viewed in the light of the Estonian experience (IP/A/ITRE/FWC/2005-60/SC4)" (PDF). European Parliament. October 2006. Retrieved 2007-06-02. {{cite journal}}: Cite journal requires |journal= (help)
^ ^a ^b Linda Seebach (2005-09-02). "Shell's ingenious approach to oil shale is pretty slick". Rocky Mountain News. Retrieved 2007-06-02. {{cite web}}: Check date values in: |date= (help)
^ Schmidt, S. J. (2003). "New directions for shale oil:path to a secure new oil supply well into this century: on the example of Australia" (PDF). Oil Shale. A Scientific-Technical Journal. 20 (3). Estonian Academy Publishers: 333–346. ISSN 0208-189X. Retrieved 2007-06-02.
^ Leah Krauss (2006-11-07). "Analysis: Israel sees shale replacing oil". United Press International. Retrieved 2007-07-29. {{cite web}}: Check date values in: |date= (help)
^ Tiikma, Laine; Johannes, Ille; Pryadka, Natalja (2002). "Co-pyrolysis of waste plastics with oil shale". Retrieved 2007-10-20. {{cite journal}}: Cite journal requires |journal= (help)
^ Tiikma, Laine; Johannes, Ille; Luik, Hans (March 2006). "Fixation of chlorine evolved in pyrolysis of PVC waste by Estonian oil shales". Journal of Analytical and Applied Pyrolysis. Retrieved 2007-10-20.
^ Veski, R.; Palu, V.; Kruusement, K. (2006). "Co-liquefaction of kukersite oil shale and pine wood in supercritical water" (PDF). Oil Shale. A Scientific-Technical Journal. 23 (3). Estonian Academy Publishers: 236–248. ISSN 0208-189X. Retrieved 2007-06-16.
^ Aboulkas, A.; El Harfi, K.; El Bouadili, A.; Benchanaa, M.; Mokhlisse, A.; Outzourit, A. (2007). "Kinetics of co-pyrolysis of Tarfaya (Morocco) oil shale with high-density polyethylene" (PDF). Oil Shale. A Scientific-Technical Journal. 24 (1). Estonian Academy Publishers: 15–33. ISSN 0208-189X. Retrieved 2007-06-16.
^ Ozdemir, M.; Akar, A.; Aydoğan, A.; Kalafatoglu, E.; Ekinci, E. (2006-11-07). "Copyrolysis of Goynuk oil shale andthermoplastics" (PDF). Amman, Jordan. Retrieved 2007-06-29. {{cite journal}}: Check date values in: |date= (help); Cite journal requires |journal= (help)
^ Cleveland, Cutler J.; Costanza, Robert; Hall, Charles A. S.; Kaufmann, Robert (1984-08-31). "Energy and the U.S. Economy: A Biophysical Perspective" (PDF). Science. 225 (4665). American Association for the Advancement of Science: 890–897. ISSN: 00368075. Retrieved 2007-08-28. {{cite journal}}: Check date values in: |date= (help)CS1 maint: date and year (link)
^ Spencer Reiss (2005-12-13). "Tapping the Rock Field". WIRED Magazine. Retrieved 2007-08-27. {{cite web}}: Check date values in: |date= (help)
^ ^a ^b Greenpeace Australia Pacific (2005-03-03). "Climate-changing shale oil industry stopped". Retrieved 2007-06-28. {{cite web}}: Check date values in: |date= (help)
^ Renato Orsato (2004). "Eco-Activism: Greenpeace, the Oil Industry and the Stuart Oil Shale Project in Australia". Retrieved 2007-10-20. {{cite web}}: Unknown parameter |Publisher= ignored (|publisher= suggested) (help)
^ "Greenpeace happy with part closure of shale oil plant". 2004-07-22. Retrieved 2007-10-20. {{cite web}}: Check date values in: |date= (help); Unknown parameter |Publisher= ignored (|publisher= suggested) (help)
^ Jim Bartis, RAND Corporation (2006). "Unconventional Liquid Fuels Overview. 2006 Boston World Oil Conference" (PDF). Association for the Study of Peak Oil & Gas - USA. Retrieved 2007-06-28. {{cite journal}}: Cite journal requires |journal= (help)

[koel-1] Koel, Mihkel (1999). "Estonian oil shale". Oil Shale. A Scientific-Technical Journal (Extra). Estonian Academy Publishers. ISSN 0208-189X. Retrieved 2007-07-21.

[patent-2] "Process for the recovery of hydrocarbons from oil shale". FreePatentsOnline. Retrieved 2007-11-03.

[qian-3] Qian, Jialin; Wang, Jianqiu (2006-11-07). "World oil shale retorting technologies" (PDF). Amman, Jordan. Retrieved 2007-06-29. {{cite journal}}: Check date values in: |date= (help); Cite journal requires |journal= (help)

[symposium-4] Brendow, K. (2003). "Global oil shale issues and perspectives. Synthesis of the Symposium on Oil Shale. 18-19 November, Tallinn" (PDF). Oil Shale. A Scientific-Technical Journal. 20 (1). Estonian Academy Publishers: 81–92. ISSN 0208-189X. Retrieved 2007-07-21.

[Jordan-5] Hamarneh, Yousef (1998; 2006). "Oil Shale Resources Development In Jordan" (PDF). Amman: Natural Resources Authority of Jordan. Retrieved 2007-06-16. {{cite journal}}: Check date values in: |date= (help); Cite journal requires |journal= (help)

[AICHE-6] ^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j Burnham, Alan K.; McConaghy, James R. (2006-10-16). "Comparison of the Acceptability of Various Oil Shale Processes" (PDF). Golden: 26th Oil Shale Symposium. UCRL-CONF-226717. Retrieved 2007-06-23. {{cite journal}}: Check date values in: |date= (help); Cite journal requires |journal= (help)

[assessment-7] "An Assessment of Oil Shale Technologies" (PDF). June 1980. NTIS order #PB80-210115. Retrieved 2007-11-03. {{cite journal}}: Cite journal requires |journal= (help)

[oilshale2-8] Mölder, Leevi (2004). "Estonian Oil Shale Retorting Industry at a Crossroads" (PDF). Oil Shale. A Scientific-Technical Journal. 21 (2). Estonian Academy Publishers: 97–98. ISSN 0208-189X. Retrieved 2007-06-23.

[soone-9] Soone, Jüri; Riisalu, Hella; Kekisheva, Ljudmilla; Doilov, Svjatoslav (2006-11-07). "Environmentally sustainable use of energy and chemical potential of oil shale" (PDF). Amman, Jordan. Retrieved 2007-06-29. {{cite journal}}: Check date values in: |date= (help); Cite journal requires |journal= (help)

[fossilenergy-10] ^ ^a ^b ^c ^d ^e ^f ^g ^h "Strategic Significance of America's Oil Shale Resource. Volume II Oil Shale Resources, Technology and Economics" (PDF). Office of Deputy Assistant Secretary for Petroleum Reserves; Office of Naval Petroleum and Oil Shale Reserves; U.S. Department of Energy. 2004. Retrieved 2007-06-23. {{cite journal}}: Cite journal requires |journal= (help) Cite error: The named reference "fossilenergy" was defined multiple times with different content (see the help page).

[fushun-11] Purga, Jaanus (2004). "Today's rainbow ends in Fushun" (PDF). Oil Shale. A Scientific-Technical Journal. 21 (4). Estonian Academy Publishers: 269–272. ISSN 0208-189X. Retrieved 2007-06-23.

[shaletechnologies-12] "Shale Technologies". Shale Technologies, LLC. Retrieved 2007-06-24.

[Estonia-13] Liive, Sandor (2007). "Oil Shale Energetics in Estonia" (PDF). Oil Shale. A Scientific-Technical Journal. 24 (1). Estonian Academy Publishers: 1–4. ISSN 0208-189X. Retrieved 2007-06-24.

[rintekno-14] "New shale oil line for VKG Oil AS" (PDF). Rintekno Newsletter. 20. Rintekno Oy. 2006. Retrieved 2007-06-24.

[ATPpatent-15] "Dry thermal processor. US Patent 5366596". PatentGenius. Retrieved 2007-11-03.

[remediation-16] "Technology Details: Alberta Taciuk Process". aboutREMEDIATION. Retrieved 2007-06-24.

[Alberta-17] Chandler, Graham (2006). "US eyes Alberta as model for developing oil shale" (PDF). Alberta Oil. 2 (4): 16–18. Retrieved 2007-06-24.

[OSEC-18] "OSEC's Process: A Proven Technology". Oil Shale Exploration Company, LLC. Retrieved 2007-06-24.

[worldoil-19] Fischer, Perry A. (2005). "Hopes for shale oil are revived". World Oil. 226 (8). Retrieved 2007-06-24.

[homtov-20] Sandler, Neal (2006). "Israel assesses new oil shale technology" (PDF). Energy Economist (297). Platts. Retrieved 2007-11-11.

[dyni-21] Dyni, John R. (2006). "Geology and resources of some world oil-shale deposits. Scientific Investigations Report 2005–5294" (PDF). U.S. Department of the Interior. U.S. Geological Survey. Retrieved 2007-07-09. {{cite journal}}: Cite journal requires |journal= (help)

[DOE-22] ^ ^a ^b ^c ^d ^e ^f ^g "Secure Fuels from Domestic Resources: The Continuing Evolution of America's Oil Shale and Tar Sands Industries" (PDF). United States Department of Energy. 2007: 1–68. Retrieved 2007-07-11. {{cite journal}}: Cite journal requires |journal= (help) Cite error: The named reference "DOE" was defined multiple times with different content (see the help page).

[redleaf-23] Patten, James W. (2007). "Red-Leaf Resources. Presentation at the Utah Energy Summit" (PDF). Utah Energy Summit. Retrieved 2007-11-11. {{cite journal}}: Cite journal requires |journal= (help)

[comustion-24] 27th Oil shale Symposium Proceedings, Colorado School of Mines Press, 2007

[laherrere-25] Laherrère, Jean (2005). "Review on oil shale data" (PDF). Hubbert Peak. Retrieved 2007-06-17. {{cite journal}}: Cite journal requires |journal= (help)

[xtract-26] "Xtract Ltd". Xtract Energy Plc. 2007. Retrieved 2007-07-28.

[hytort2-27] Weil, S. A.; Feldkirchner, H. L.; Punwani, D. V.; Janka, J. C. (1979-01-01), IGT HYTORT Process for hydrogen retorting of Devonian oil shales, Institute of Gas Technology,Chicago, IL, CONF-790571-3 {{citation}}: Check date values in: |date= (help); Cite has empty unknown parameter: |1= (help)

[hytort-28] Rex, R.; Janka, J. C.; Knowlton, T. (1984), Cold Flow Model Testing of the Hytort Process Retort Design.17th Oil Shale Symposium, Colorado School of Mines Press, pp. 17–36

[california-29] Ennis, D.L. (2006-08-15). "Oil Shale—An Investment We Can't Afford". California Chronicle. Retrieved 2007-07-26. {{cite journal}}: Check date values in: |date= (help); Cite journal requires |journal= (help)

[equityoilt-30] Dougan, P.M.; Dockter, L. (1981), BX In Situ Oil Shale Project. 14th Oil Shale Symposium, Colorado School of Mines Press, pp. 118–127

[sandia-31] Tyner, C.E.; Parrish, R.L.; Major, B.H.; Lekas, J.M. (1982), Sandia/Geokinetics Retort 23: A Horizontal In Situ Retorting Experiment. 15th Oil shale Symposium Proceedings, Colorado School of Mines Press, pp. 370–384 Cite error: The named reference "sandia" was defined multiple times with different content (see the help page).

[geokinetics-32] Costimiris, E.C. (1982), Investigation of the Geokinetics horizontal in-situ oil-shale-retorting process. Annual Report 1981, Geokinetics, Inc

[chimney-33] Lombard, D.B.; Carpenter, H.C. (1967), "Recovering Oil by Retorting a Nuclear Chimney in Oil Shale", Journal of Petroleum Technology (19), Society of Petroleum Engineers: 727–734

[gregg-34] Gregg, M.L.; Campbell, J.H. (1980), Sweep efficiency modeling of modified in-situ retorts. 13th Oil shale Symposium Proceedings, Colorado School of Mines Press, pp. 87–100 Cite error: The named reference "gregg" was defined multiple times with different content (see the help page).

[multimineral-35] "Integrated in situ shale oil and mineral recovery process". FreePatentsOnline. 1981-08-25. United States Patent 4285547. Retrieved 2007-11-11. {{cite web}}: Check date values in: |date= (help)

[shell-36] "Oil Shale Test Project. Oil Shale Research and Development Project" (PDF). Shell Frontier Oil and Gas Inc. 2006-02-15. Retrieved 2007-06-30. {{cite journal}}: Check date values in: |date= (help); Cite journal requires |journal= (help) Cite error: The named reference "shell" was defined multiple times with different content (see the help page).

[fortune-37] Jon Birger (2007-11-01). "Oil shale may finally have its moment". Fortune. Retrieved 2007-11-17. {{cite journal}}: Check date values in: |date= (help); Cite journal requires |journal= (help)

[EGLl-38] "Innovation in Shale Technology". EGL Shale. 2006-11-16. Retrieved 2007-07-06. {{cite web}}: Check date values in: |date= (help)

[chevron-39] "Environmental Assessment, Chevron Oil Shale Research, Development & Demonstration" (PDF). U.S. Department of Interior. 2006. Retrieved 2007-07-06. {{cite journal}}: Cite journal requires |journal= (help)

[Burnham-40] A.K. Burnham (2003-08-20). "Slow Radio-Frequency Processing of Large Oil Shale Volumes to Produce Petroleum-like Shale Oil" (PDF). Lawrence Livermore National Laboratory. UCRL-ID-155045. Retrieved 2007-06-28. {{cite journal}}: Check date values in: |date= (help); Cite journal requires |journal= (help)

[upi-41] Megan Harris (2007-07-20). "Oil from shale could meet need". United Press International. Retrieved 2007-08-19. {{cite web}}: Check date values in: |date= (help)

[electro-42] "Electrically enhanced oil production using DC technology" (PDF). Electro-Petroleum, Inc. Retrieved 2007-11-11. {{cite journal}}: Cite journal requires |journal= (help)

[43] Robert Rapier (2006-06-12). "Oil Shale Development Imminent". R-Squared Energy Blog. Retrieved 2007-06-22. {{cite journal}}: Check date values in: |date= (help); Cite journal requires |journal= (help)

[rand-44] Cite error: The named reference rand was invoked but never defined (see the help page).

[eu-45] "A study on the EU oil shale industry viewed in the light of the Estonian experience (IP/A/ITRE/FWC/2005-60/SC4)" (PDF). European Parliament. October 2006. Retrieved 2007-06-02. {{cite journal}}: Cite journal requires |journal= (help)

[rockymountainnews-46] Linda Seebach (2005-09-02). "Shell's ingenious approach to oil shale is pretty slick". Rocky Mountain News. Retrieved 2007-06-02. {{cite web}}: Check date values in: |date= (help)

[schmidt-47] Schmidt, S. J. (2003). "New directions for shale oil:path to a secure new oil supply well into this century: on the example of Australia" (PDF). Oil Shale. A Scientific-Technical Journal. 20 (3). Estonian Academy Publishers: 333–346. ISSN 0208-189X. Retrieved 2007-06-02.

[israel-48] Leah Krauss (2006-11-07). "Analysis: Israel sees shale replacing oil". United Press International. Retrieved 2007-07-29. {{cite web}}: Check date values in: |date= (help)

[co-pyrolisis-49] Tiikma, Laine; Johannes, Ille; Pryadka, Natalja (2002). "Co-pyrolysis of waste plastics with oil shale". Retrieved 2007-10-20. {{cite journal}}: Cite journal requires |journal= (help)

[co-pyrolisis2-50] Tiikma, Laine; Johannes, Ille; Luik, Hans (March 2006). "Fixation of chlorine evolved in pyrolysis of PVC waste by Estonian oil shales". Journal of Analytical and Applied Pyrolysis. Retrieved 2007-10-20.

[veski1-51] Veski, R.; Palu, V.; Kruusement, K. (2006). "Co-liquefaction of kukersite oil shale and pine wood in supercritical water" (PDF). Oil Shale. A Scientific-Technical Journal. 23 (3). Estonian Academy Publishers: 236–248. ISSN 0208-189X. Retrieved 2007-06-16.

[Morocco-52] Aboulkas, A.; El Harfi, K.; El Bouadili, A.; Benchanaa, M.; Mokhlisse, A.; Outzourit, A. (2007). "Kinetics of co-pyrolysis of Tarfaya (Morocco) oil shale with high-density polyethylene" (PDF). Oil Shale. A Scientific-Technical Journal. 24 (1). Estonian Academy Publishers: 15–33. ISSN 0208-189X. Retrieved 2007-06-16.

[turkey2-53] Ozdemir, M.; Akar, A.; Aydoğan, A.; Kalafatoglu, E.; Ekinci, E. (2006-11-07). "Copyrolysis of Goynuk oil shale andthermoplastics" (PDF). Amman, Jordan. Retrieved 2007-06-29. {{cite journal}}: Check date values in: |date= (help); Cite journal requires |journal= (help)

[science2-54] Cleveland, Cutler J.; Costanza, Robert; Hall, Charles A. S.; Kaufmann, Robert (1984-08-31). "Energy and the U.S. Economy: A Biophysical Perspective" (PDF). Science. 225 (4665). American Association for the Advancement of Science: 890–897. ISSN: 00368075. Retrieved 2007-08-28. {{cite journal}}: Check date values in: |date= (help)CS1 maint: date and year (link)

[wired-55] Spencer Reiss (2005-12-13). "Tapping the Rock Field". WIRED Magazine. Retrieved 2007-08-27. {{cite web}}: Check date values in: |date= (help)

[greenspace-56] Greenpeace Australia Pacific (2005-03-03). "Climate-changing shale oil industry stopped". Retrieved 2007-06-28. {{cite web}}: Check date values in: |date= (help)

[57] Renato Orsato (2004). "Eco-Activism: Greenpeace, the Oil Industry and the Stuart Oil Shale Project in Australia". Retrieved 2007-10-20. {{cite web}}: Unknown parameter |Publisher= ignored (|publisher= suggested) (help)

[58] "Greenpeace happy with part closure of shale oil plant". 2004-07-22. Retrieved 2007-10-20. {{cite web}}: Check date values in: |date= (help); Unknown parameter |Publisher= ignored (|publisher= suggested) (help)

[BartisBoston-59] Jim Bartis, RAND Corporation (2006). "Unconventional Liquid Fuels Overview. 2006 Boston World Oil Conference" (PDF). Association for the Study of Peak Oil & Gas - USA. Retrieved 2007-06-28. {{cite journal}}: Cite journal requires |journal= (help)

[1]

[2]

[3]

[4]

[5]

[6]

[7]

[8]

[9]

[10]

[11]

[12]

[13]

[14]

[15]

[16]

[17]

[18]

[19]

[20]

[21]

[22]

[23]

[24]

[25]

[26]

[27]

[28]

[29]

[30]

[31]

[32]

[33]

[34]

[35]

[36]

[37]

[38]

[39]

[40]

[41]

[42]

[43]

[44]

[45]

[46]

[47]

[48]

[49]

[50]

[51]

[52]

[53]

[54]

[55]

[56]

[57]

[58]

[59]