Shale oil is petroleum extracted from shale, a type of rock in the subsurface.
Literally “shale oil,” shale oil refers to two types of petroleum:
- crude oil found in shale formations
- petroleum extracted from oil shales.
Oil shales are a type of sedimentary rock that has low permeability bituminous conglomerates that can be liquefied during the extraction process.
The development of horizontal drilling and hydraulic fracturing (“fracking”) techniques has allowed oil and natural gas producers to extract resources from shale and other low-permeability rock formations. The development of these techniques has grown rapidly since the 1950s, with the United States only beginning to exploit its shale formations in the 1970s and 1980s. In the United States, the largest shale formations suitable for shale oil extraction are located on the West Coast.
