PETROLEUM AND ITS ORIGIN

petroleum means rock oil, it is naturally occurring organic material composed of hydrocarbons which occur in gaseous or liquid state in geographical traps. it is one of the most important liquid fuel in the world, and the name covers both naturally occurring unprocessed crude oil and its products. Present day material civilization would have been impossible without it, a journey which took months in the past is now completed in few days in buses and cars. The same journey of few days may be completed even in hours. Petroleum is recovered mostly through oil drilling, this comes after the studies of structural geology, and other studies of the reservoir must have been done. Crude oil is the basic raw material for refining industry,it is not only unique, but the entire organic chemistry could be studied in it. Petroleum contains almost all known hydrocarbons and non-hydrocarbons. Crude oil is refined and separated most easily by distillation into large number of products from gasoline and kerosene to asphalt and chemical reagents used to make plastics and pharmaceuticals. Petroleum is used in manufacturing a variety of materials and it is estimated in 2014 that the world consumes about 90 million barrels each day. The use of these petroleum products have negative impact on earth's biosphere such as releasing a range of pollutants into the air if not purified, hence must undergo rigorous treatment.
ORIGIN OF PETROLEUM
Opinions have been divided regarding the formation of petroleum, although several theories were put forward to explain the formation of petroleum, only three were widely accepted because they were able to explain some of the important properties associated with petroleum. these properties include
The presence of chlorophyll and heamin and resins in it.
The presence of nitrogen and sulfur compounds in it
Its optically active nature
Its association with sodium and chlorides(brine)

THEORIES OF PETROLEUM FORMATION

CARBIDE THEORY
This theory proposed that petroleum is of inorganic origin formed by the hydrogenation and polymerization of lower hydrocarbons. The lower hydrocarbons are in turn formed by the action of water on inorganic carbides of metals. the carbides are also formed by the reaction of metals and carbon under high temperature and   pressure inside the earth.

ENGLER THEORY
According to engler petroleum is of organic origin. he suggested that petroleum is formed by decay and decomposition of mariner animals under high pressure and temperature. The theory suggested that the sulphurdioxide gas given out during volcanic eruption beside sea water kills fishes and other marine animals which pills up beside the volcano, after hundreds of years, these animals start decomposing under the influence of high pressure and temperature to form petroleum.

MODERN THEORY
According to modern views petroleum is believed to be formed by the decay and decompostion of marine animals as well as that of vegetable organism of the prehistoric forests i.e it is of animal as well as plant origin. it is thought that due to some upheavals or earthquakes, these prehistoric forests and sea animals were buried under the earth crust of earth. due to prolonged action of high temperature and pressure in the interior of earth for ages , they biologically decompose into petroleum.