Oil Shale is fine grained rock, contains significant amounts of Kerogen, from which technology can extract liquid hydrocarbons. Oil
shale requires more processing then crude oil, which is more expensive. Most exploitation of oil shale involves mining followed
by shipping elsewhere, after which one can burn it directly to generate electricity, or undertake further processing. The
most-often used methods of surface mining are open pit mining and strip mining. These procedures remove most of the overlying
material to expose the oil shale deposits, and are practical when the deposits are close to the surface. The worlds
largest Oil Shale reserve is located in Colorado, Wyoming, and Utah at the Green River Basin Oil Shale Formation.
Shale Gas, natural gas located in shale rock, is located
far beneathe the earths surface. Because shales ordinarily have insufficient permeability to allow significant fluid
flow to a well bore, most shales are not sources of natural gas. Shale gas is one of a number of “unconventional”
sources of natural gas; other unconventional sources of natural gas include coalbed methane, tight sandstones, and methane
hydrates.
Shale has low matrix permeability, so gas production in commercial quantities
requires fractures to provide permeability. Shale gas has been produced for years from shales with natural fractures; the
shale gas boom in recent years has been due to modern technology in creating extensive artificial fractures around well bores.
Horizontal drilling is often used with shale gas wells.
