TAR SANDS AND OIL SHALE

Amar Chand Akhilesh Mishra Akshit Tripathi Akul Jain Ankit Kumar

IIT Roorkee

TAR SANDS

INTRODUCTIONOil sand is either loose sand or partially consolidated sandstone containing a naturally occurring mixture of sand, clay, and water, saturated with a dense and extremely viscous form of petroleum technically referred to as bitumen.

Glimpses of Tar Sands mines

History• First sources discovered by Geological Survey

of Canada in Alberta in 1884.• Several extraction plants were established later

in 20th Century in Canada.• Demand highly increased during World War.• Alberta, Canada is currently second largest

source of Tar sands, after Saudi Arabia.

Amount of deposits

Composition

• Formed from biodegradation and water-washing of light crude due to lack of cap rock

• 10-20% bitumen • 80-85% mineral matter including sands, clays • 4-6% water.• Yield liquid hydrocarbons, upon further

processing, can be converted to furnished petroleum products.

Oil sand production methods

• The oil sand industry uses two major methods to produce oil from bituminous sands

• 1. Open Pit mining• 2. In-situ mining: Several process are used for this

such as:o Steam Assisted Gravity Drainage(SAGD)o Cyclic Steam Stimulationo Toe to Heel Injection

Open-pit mining• Approximately 20% of the oil sands lie close enough to the

earth’s surface to be mined, which impacts 3% of the surface area of the oil sands region.

• Open-pit mining is similar to many coal-mining operations. Large shovels scoop the oil sands into trucks, which take it to crushers, where the large clumps of clay are broken down. The oil sand is then mixed with water and transported by pipeline to a plant, where the bitumen is separated from the other components.

• Tailings ponds are an operating facility common to all types of surface mining. In the oil sands, tailings consisting of water, sand, clay and residual oil are pumped to these basins – or ponds – where settling occurs and water is recycled for reuse in the process. When the ponds are no longer required, the land is reclaimed.

In-situ drilling• The majority of the oil sands lie more than 70 metres (200 feet)

below the ground, and are too deep to be mined. These reserves can be recovered in situ (in place) by drilling wells. In situ drilling accounts for 80% of oil sands reserves and these reserves are located below 97% of the land in the oil sands sector.

• Drilling methods disturb a small amount of land and do not require tailings ponds. Advanced technology is used to inject steam, combustion or other sources of heat into the reservoir. The heat warms the bitumen so it can be pumped to the surface through recovery wells.

• Advances in technology, such as directional drilling, enable in situ operations to drill multiple wells (sometimes more than 20) from a single location, further reducing surface disturbance.

Steam Assisted Gravity Drainage

• The majority of in situ operations use steam-assisted gravity drainage, or SAGD. This method involves pumping steam underground through a horizontal well to liquefy the bitumen, which is then pumped to the surface through a second recovery well. 

Cyclic Steam Stimulation

• A second method – cyclic steam stimulation – pumps steam down a vertical well to soak or liquefy the bitumen, which is then pumped to the surface through the same well. This technique is repeated until the oil is removed.

• Unlike SAGD, this technique has the advantage of requiring only a single production well.

Toe to Heel Air Injection (THAI)

• This is an in situ combustion process that has shown to produce more resource, while significantly limiting the environmental footprint. While it uses some water for the intitial steaming, it is returned to the surface, treated and returned to the environment.

• To begin the process, bitumen around the “toe” of the horizontal well is heated with steam. Once this approximately three-month heating cycle in a bitumen reservoir is complete, the steam is shut off and air is injected into the vertical well to create a combustion reaction in the reservoir.

• Through the controlled injection of air, a thick combustion front begins to slowly move towards the “heel” of the horizontal well. As it heats up, the bitumen drains into the horizontal production well and brought to the surface through natural pressure.

• Because the combustion front heats the bitumen to 400 degrees, the oil is also partially upgraded underground. The heat causes a portion of the asphaltine content of the oil to be left behind as coke that is the fuel for the continued combustion.

Zero Liquid Discharge• ZLD has a number of benefits, such as recycling more than 90 per

cent of the facility’s water. This allows a company to recycle 90 per cent of injection steam.

• As explained earlier, in SAGD, steam is injected in a well underground to heat the bitumen, which flows into a second, producer well, and then up to the surface.

• But in addition to bitumen, water with a high saline content also enters the producer well as does condensed steam from the injection well. This is usually disposed by pumping it into a disposal well underground. However, ZLD treats the water to remove salts and recycles it to produce more injection steam and leaves only solids to be disposed. This way, more than 90 per cent of the injection steam required to an operation is recycled continuously and very little water is drawn from underground aquifers.

• Expanding ZLD capacity has helped companies reach new production records (barrels per day) while saving significant costs that would have been spent on third-party wastewater disposal.

The world's largest deposits of bitumen are in (Alberta)Canada.

Canada has abundant resources of bitumen and crude oil, with an estimated remaining ultimate potential of 54 billion cubic metres (340 billion barrels).

Tar sands do have one historic economic benefit: it is still used as a road paving material.

Since Canada will have more than enough energy to meet its growing needs, the excess oil production from its oil sands will probably go to export.

The major importing country will probably continue to be the United States, although there is increasing demand for oil, particularly heavy oil, from growing in Asian countries such as China and India.

Economics

An oil price of $100/bbl is sufficient to promote active growth in oil sands production.

Major Canadian oil companies have announced expansion plans and foreign companies are investing significant amounts of capital, in many cases forming partnerships with Canadian companies.

Investment has been shifting towards in-situ steam assisted gravity drainage (SAGD) projects and away from mining and upgrading projects, as oil sands operators foresee better opportunities from selling bitumen and heavy oil directly to refineries than from upgrading it to synthetic crude oil.

Costs and Production

Continue….. The Canadian Energy Research Institute (CERI)

estimated that in 2012 the average plant gate costs (including 10% profit margin) of primary recovery was $30.32/bbl, of SAGD was $47.57/bbl, of mining and upgrading was $99.02/bbl, and of mining without upgrading was $68.30/bbl.

 A more likely scenario is that by 2035, Canadian oil sands bitumen production will reach 800,000 m3/d (5.0 million barrels/day), 2.6 times the production for 2012.

Oil sands extraction can affect the land , water and air.

The land affect when the bitumen is initially mined.

The water resources by its requirement for large quantities of water during separation of the oil and sand.

The air due to the release of carbon dioxide and other emissions.

Environmental Issues

Wetlands can not be reclaimed.

Forest ecosystems are too complex and poorly understood to simply put all the pieces back together.

Soil problems. Cost , time and

accountability.

Problems With Reclamation

Other Problems:- Leaking pipes can pollute ground water. Tailing ponds leak their toxins to surrounding

areas and ground water. when acidic compounds are released into the air

these substances can rise very high into the atmosphere, where they mix and react with water, oxygen, and other chemicals to form more acidic pollutants ,known as acid rain.

Increases Global warming.

Oil Shale

Introduction:-• The term oil shale generally

refers to any sedimentary rock that contains solid bituminous materials that are released as petroleum like liquids when the rock is heated in the chemical process of Pyrolysis.

• Countries like Estonia ,China , Brazil and Germany have well established oil shale industries.

• Oil shale reserves in India are greater than 15 Billion Tons.

• Also known as “THE ROCK THAT BURNS” .

Oil shale mining site in US

Composition:-• General composition of oil shale constitutes inorganic

matrix, bitumen and kerogen.• It does not have a definite geological definition nor a specific

chemical formula, and its seams do not always have discrete boundaries. 

• 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.

• 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.

Oil shale extraction:-

• Oil shale can be mined using one of two methods: underground mining using the room-and-pillar method or surface mining.

• After mining, the oil shale is transported to a facility for retorting, a heating process that separates the oil fractions of oil shale from the mineral fraction.

• Retorting can be done above ground or underground. Also called On-situ and In-situ respectively.

Conti...• In-situ can potentially extract more oil from a given area of land

than on-situ processes, since they can access the material at greater depths than surface mines can.

• In either case, the chemical process of pyrolysis converts the kerogen in the oil shale to shale oil (synthetic crude oil), oil shale gas and spent shale.

Surface retortSource: Lawrence Livermore National

Laboratory

Oil shale reserves:- • Oil shale is found in many places around the

world with more than 600 known deposits in more than 30 countries on all continents. A 2005 estimate put the total world resources of oil shale at 411 gigatonnes.

SOURCE: https://www.enefit.jo/en/oilshale/in-the-world

Largest oil shale resources :

Publishing Year - 2012

SOURCE: Petroleum geologist Jean Laherrere, from "Oil Shale Review."

Oil shale economics:-• 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 by RAND corporation, the cost of producing a barrel of oil at a surface retorting complex in the United States, would range between US$70–95 . 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 US Department of Energy estimates that the on-situ processing would be economic at sustained average world oil prices above US$54 per barrel and in-situ processing would be economic at prices above $35 per barrel.

Oil shale in India:-• Oil Shale reserves in India are Greater than 15 Billion Tons.• North-East India is endowed with rich deposits of coal. • The coal is found in the Barail Formation of Tertiary age. • Carbonaceous shale occurs interbedded with the coal. The

presence of coal and shale has been recorded in wells drilled for hydrocarbons by ONGC and OIL.

• These formations outcrop on the surface towards the south of the oil fields in a region called the Belt of Schuppen. Studies have indicated that these coals and carbonaceous shale constitute the principal source rocks that have generated the hydrocarbons produced from the region.

• Potential locations• Assam shelf• Naga Schuppen Belt• Assam-Arakkan Fold Belt

Barriers:-• First, most of it needs to be dug out in strip mining rather

that drilled a process that has high environmental problems.

• Once dug out, it then needs to be heated to 450-500 Degree C, enriched with hydrogen via steam before the resulting oil is separated. The residue is a sludge that needs to be disposed of.

• The downsides of all this are that oil shale production create more than four times as much greenhouse gases as conventional oil production.

• The energy required to extract oil from oil shale is considerable, and this could result in a low EROEI (energy returned on energy invested) . Wastes something like 40% of its initial energy in production.

Conti...• Only when crude prices are high does oil shale

production make economic sense feasible. In theory, it has the potential to make a minor contribution to the Indian oil requirements, but it is not expected to be a panacea to our oil-dependency.

Impact on environment :-

• Oil shale production is also considered to be quite harmful to the environment.

• Both mining and processing of oil shale involve a variety of environmental impact, such as global warming and greenhouse gas emissions, disturbance of mined land, impacts on wildlife and air and water quality.

• These include acid drainage induced by the sudden rapid exposure and subsequent oxidation of formerly buried materials, the introduction of metals including mercury 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.

• It uses vast quantities of water (which are not always available where the shale is).

Shale oil and gas production leads to emission of most of the green house

gases

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