Why does oil shale require heating before it can yield oil?

Oil shale does not naturally contain liquid oil; instead, it contains a solid, waxy organic substance known as kerogen. This material is insoluble in water and organic solvents, meaning it cannot be extracted through conventional drilling or pumping methods used for liquid petroleum.123

To yield oil, the rock must undergo a process called pyrolysis. During this process, the oil shale is heated to high temperatures—typically between 325 °C and 550 °C (620 °F to 1,020 °F), depending on whether the method is performed aboveground or in situ. This intense heat breaks the chemical bonds of the complex kerogen macromolecules, transforming the solid organic matter into recoverable liquid and gaseous hydrocarbons that resemble conventional petroleum. Essentially, the heating process artificially replicates the natural geologic conditions of heat and pressure that, over vast periods of time, generate oil from source rocks.4512