Unconventional hydrocarbons: Oil shales, heavy oil, tar sands, shale oil, shale gas and gas hydrates

Abstract

For many decades conventional oil which could be produced at low cost was present in abundance. A low oil price gave no incentive to look for other types of resources. It is now clear, however, that we are gradually running out of new sedimentary basins to explore and that the reserves of conventional oil which can be produced cheaply are limited.