What is tar sand

Oil sands

Lexicon> letter O> oil sands

Definition: sand that contains hydrocarbons that can be extracted as unconventional petroleum

More general term: unconventional fossil fuel

English: oil sand

Category: Energy sources

Author: Dr. Rüdiger Paschotta

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Original creation: 08/22/2011; last change: 15.05.2021

URL: https://www.energie-lexikon.info/oelsand.html

Oil sands (also Tar sands called) are fine-grained rocks that contain hydrocarbons. The hydrocarbons are a type of crude oil which, however, cannot simply be pumped out in liquid form, but has to be separated from the oil sands using complex processes. Oil sand deposits are therefore considered to be non-conventionally exploitable oil deposits.

Since the conventional (i.e. that can be extracted using conventional methods) oil deposits are increasingly running out and the price of oil on the world market has already risen considerably, unconventional deposits such as oil sands are becoming increasingly interesting from an economic point of view, even though the production costs are massively higher than, for example, oil deposits in the Middle East or in the North Sea. The total potential of the technically and (if the oil price is high enough) economically recoverable is very high - considerably larger than the remaining conventional deposits. Canada and Venezuela in particular have large deposits.

Oil extraction from oil sands

The extraction of oil sands or tar sands usually takes place in open-cast mining. Here z. In the Canadian province of Alberta, for example, huge areas were dug up and devastated in the process.

Deeper deposits are also exploited using “in situ” methods, in which the hydrocarbons are extracted from the sand underground. Essentially, the bitumen contained is split up by heating the oil sand, making it flowable and then pumped out. Hot steam can be introduced for heating, or part of the material is burnt underground with a supply of air.

Usable crude oil is obtained from the extracted materials in further complex process steps. Important aspects are the separation of sand, the splitting of long-chain hydrocarbons into lighter ones and the separation of harmful substances such as sulfur. Toxic chemicals are also used in large quantities.

The extraction and processing of oil sands consumes large amounts of energy, often in the form of natural gas or by using a substantial part of the extracted crude oil. This means that every liter of unconventional crude oil that can ultimately be used contains a far greater amount of gray energy than conventionally produced crude oil. Correspondingly, the environmental pollution is also much higher - on the one hand due to the high climate-damaging carbon dioxide emissions and on the other hand due to the devastation and poisoning of large areas of land in the production areas. In addition, there is a very high water consumption.

Future prospects

Although the previous use of oil sands represents only a small percentage of total global oil production, it is already causing massive environmental problems, especially in Canada. If conventional crude oil, which is gradually running out, is to be replaced on a large scale by such unconventional deposits, the environmental pollution and, in particular, the resulting climatic dangers of crude oil use would increase sharply - instead of decreasing sharply, as is absolutely necessary in the interests of climate protection. If the oil price on the world market continues to rise and remains consistently high, it would become politically more difficult to prevent such a development.

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See also: crude oil, fossil fuels, climate hazards, gray energy
as well as other articles in the energy source category