öljykiveä

Öljykiveä, also known as oil shale, is a sedimentary rock that contains a significant amount of organic matter called kerogen. This kerogen is insoluble in ordinary organic solvents but can be converted into liquid hydrocarbons, such as oil and gas, through a process called retorting, which involves heating the rock in the absence of oxygen. The world's largest deposits of oil shale are found in the United States, particularly in Colorado, Utah, and Wyoming. Other significant deposits exist in Estonia, China, and Russia.

The formation of oil shale dates back to ancient times when organic-rich muds accumulated in lakes or marine basins. Over millions of years, these sediments were buried, compressed, and heated, transforming the organic matter into kerogen. The composition of oil shale varies, but it typically consists of a mineral matrix (often dolomite or limestone) and varying amounts of kerogen. The richness of an oil shale deposit is measured by the amount of oil that can be extracted per ton of rock.

Extracting oil from oil shale can be done through two primary methods: in-situ retorting and ex-situ retorting. In-situ methods involve heating the oil shale underground, allowing the oil to be pumped out. Ex-situ methods involve mining the oil shale and then processing it in surface retorts. Both methods have environmental challenges, including water usage, land disturbance, and potential air and water pollution. Despite these challenges, oil shale has been considered a potential source of liquid fuels, particularly in regions with abundant deposits.