In-situ combustion retorting of oil shale

Abstract

The study of oil shale and attempts to produce oil from this material has a history which is intermixed with and recurrent in the petroleum literature. Indeed the word petroleum was applied to shale oil before the first oil well and in England as early as the 14th century.1 The first shales to be processed for oil were the Torbanites of Scotland and kerosene shale of New South Wales. It was a Scottish professor who first used the term kerogen to designate the oil yielding material in oil shale. The first study of kerogen was motivated by an 1858 law suit on whether Torbani te was a coal or an oil shale. Since this t ime oil shale has come to be distinguished from coal and tar sands because the latter can be processed by solvents and the oil shale processed by destructive distillation. The first literature describing oil shale properties dates to the late 18th century in Europe and the first patents on oil shale use date to about the same period. 1 Oil shale may be defined as a shale rich in organic material and which when heated or subjected to destructive distillation yields an oil or gaseous hydrocarbon. Oil shale is sometimes also defined as containing a minimum weight of one-third ash. 2 The organic content and mineral matter contained in oil shales are widely variable making a more specific definition difficult. Oil shales are distributed throughout the world, al though the richest and most abundant identified deposits are contained in the Green River Format ion of Utah, Wyoming and Colorado. 3 These resources are summarized in Table 1. The extent of these