What is Oil Shale?

OI L S HAL E is a sedimentary rock that is rich in an organic chemical called kerogen. Kerogen breaks down and releases hydrocarbons when heated at high temperature. The hydrocarbons in oil shale can be used as an alternative to petroleum or natural gas.

Like traditional oil and natural gas, oil shale is also a fossil fuel that was formed inside Earth millions of years ago. The organic remains of plants and animals lying on river beds and ocean floors encountered gradual heat and pressure and slowly got transformed into a waxy substance called kerogen.

Oil shale is considered to be a precursor to oil and natural gas — with more pressure and heat and with the passage of geological time, kerogen gets converted to oil.

Oil shale can be mined and processed to generate fuel. As the oil in oil shale is in solid form, it cannot be pumped directly out of the ground. It is first mined, then heated to a high temperature and the resultant liquid is separated to get oil. Another method involves heating the oil shale while it is still underground and then pumping the liquid to the surface.

The extraction process, however, is complex and more expensive compared to traditional oil extraction techniques. Also, the extraction process is not eco-friendly as it produces large quantities of greenhouse gases besides requiring huge amounts of water. Therefore, production of shale oil as an alternative fuel has not really taken off commercially barring in a few countries like China, Estonia and the US. Shale oil was produced during both the World Wars to meet fuel requirements but most projects were abandoned subsequently.