Oil shale

Oil shale

Oil shale is an organic-rich fine-grained sedimentary rock. Deposits of oil shale occur around the world, including major deposits in the United States. Heating oil shale to a sufficiently high temperature causes the chemical process of pyrolysis to yield a vapor. Oil shale can also be burned directly in furnaces as a low-grade fuel for power generation and district heating.

About Oil shale in brief

Summary Oil shaleOil shale is an organic-rich fine-grained sedimentary rock. Deposits of oil shale occur around the world, including major deposits in the United States. Heating oil shale to a sufficiently high temperature causes the chemical process of pyrolysis to yield a vapor. Upon cooling the vapor, the liquid shale oil—an unconventional oil—is separated from combustible oil-shale gas. Oil shale can also be burned directly in furnaces as a low-grade fuel for power generation and district heating or used as a raw material in chemical and construction-materials processing. While oil sands do originate from the biodegradation of oil, heat and pressure have not transformed the kerogen in oil shale into petroleum, that means that its maturation does not exceed early mesocatagenetic. Oil shales vary considerably in their mineral content, chemical composition, age, type of kerogen, and depositional history and not all oil shales would necessarily be classified as shales in the strict sense. They are not geologically nor geochemically distinctive rock but rather ‘economic’ term. Their common defining feature is low solubility in low-boiling organic solvents and generation of liquid organic products on thermal decomposition. The ratio of organic matter to mineral matter lies approximately between 0. 75: 5 and 1. 5: 5. The organic matter inOil shale has an atomic ratio of hydrogen to carbon approximately 1. 2 to 1. 8 times lower than for crude oil and about 1.5 to 3 times higher than for coals.

While the bitumen portion of oilShale is soluble in carbon disulfide, kerogen portion is insoluble in carbonDisulfide and may contain iron, vanadium, nickel, molybdenum, and uranium. Some deposits contain significant fossils; Germany’s Messel Pit has the status of a Unesco World Heritage Site. Inorganic matrix can contain quartz clays, pldspars, carbonates, silicates and some minerals. Geologists can classify oil shale on the basis of their composition as carbonate-rich shales or siliceous shales. This classification is based on the initial designs petrographic terms from coal, lacustrine or marine environment. The most commonly used classification of oilshales is van Kreen diagram, which assigns oil kerogen types, depending on the hydrogen, carbon, oxygen, and oil content of the original organic matter. The total world resources of oil Shales equivalent of 6. 05 trillion barrels of oil in place is estimated to be 6.05 trillion barrels, according to a 2016 estimate of global deposits set the total world reserves of oil. OilShale gains attention as a potential abundant source of oil whenever the price of crude oil rises. It does not have a definite geological definition nor a specific chemical formula, and its seams do not always have discrete boundaries. It differs from oil-bearing shales, shale deposits that contain petroleum that is sometimes produced from drilled wells.