Fossil Fuels Formation and Distribution Fossil Fuels Coal
Fossil Fuels Formation and Distribution
Fossil Fuels Ü Coal Ü Oil (Petroleum) Ü Natural Gas
Formation of Fossil Fuels – common conditions Ü High Organic Production Ü Burial of organic material Ü Reducing conditions – little or no free oxygen Ü Reducing conditions preserve organic matter Ü Coal and Petroleum diverge from here
Formation of Coal Ü Accumulation of land plant material Ü Reducing conditions – coastal and inland swamps
Formation of Coal Ü Organic accumulation is greater than destruction (because of reducing conditions) Ü Organic matter builds up to form peat
Formation of Coal Ü Peat is compressed to form lignite – brown coal Ü Lignite is compressed and volatile compounds are lost to form bituminous coal – soft coal Ü Bituminous coal is further compressed and heated to form anthracite – hard coal
Formation of Petroleum and Natural Gas Ü Accumulation of organic material – typically marine mud Ü Burial and preservation of organic material – reducing conditions Ü Reducing conditions in deep sea or on continental shelves during times of unusual oceanic
Formation of Petroleum and Natural Gas Ü Black, organic-rich mud is buried deeper and converted to rock – shale Ü With burial, the organic matter is heated Ü When heat is sufficient (but not too great) – in the range of 100 -300 degrees C – the organic matter is “cooked” and oil forms Ü Process is called thermal maturation
Formation of Petroleum and Natural Gas Ü If heat is greater than 300 degrees C, the liquid petroleum is further broken down to form natural gas Ü If heat is too great, even the natural gas is broken down to form carbon dioxide, which has no value as a fuel
Migration and Concentration Ü Petroleum must leave source rock Ü Process is called migration Ü Migration is essential because most source rocks are too fine-grained to enable easy extraction of the oil Ü To be economically concentrated, petroleum must migrate to a reservoir rock with a trap
Examples of Petroleum Traps
Petroleum Resources Ü Conditions for source rock are rare Ü Conditions for maturation must be just right Ü Migration must not let petroleum escape to surface Ü Reservoir rock must be present Ü Trap must exist before migration occurs
Where did the U. S. Petroleum Industry begin? Ü Right here in New York! Ü First gas well – Fredonia, New York
Distribution of Petroleum Ü Economic accumulations of petroleum only occur when all of these conditions are met Ü These conditions and the sequence of occurrence do not occur everywhere Ü Conditions are most likely where there are thick accumulations of sedimentary rock – in sedimentary basins
Some of the world’s most productive sedimentary basins Ü Saudi Arabia Ü Kuwait Ü Alaska – north slope Ü Texas – Louisiana Gulf Coast Ü Iraq and Iran Ü Mexico Ü Venezuela
Refining of Petroleum Ü Heat and/or chemical treatment to produce: Ü Gasoline Ü Diesel Fuel Ü Kerosene Ü Liquified Propane (LPG) Ü Petroleum bases for plastics
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