Petroleum Origin Neeraj

7/28/2019 Petroleum Origin Neeraj

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Neerajkumar Bhusari

200903041018


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Abiogenic petroleum origin is a hypothesis thatwas proposed as an alternative mechanism ofpetroleum origin.

According to the abiogenic hypothesis,petroleum was formed from deep carbon

deposits, perhaps dating to the formation of theEarth.

Supporters of the abiogenic hypothesis suggeststhat more petroleum exists on Earth thancommonly thought, and that petroleum may

originate from carbon-bearing fluids thatmigrate upward from the mantle (Very viscouslayer of earth between crust and outer core).


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Although the abiogenic hypothesis was accepted by manygeologists in the former Soviet Union, it fell out of favor atthe end of the 20th century because it never made any usefulprediction for the discovery of oil deposits.

The abiogenic origin of petroleum has also recently been

reviewed in detail by Glasby, who raises a number ofobjections, including that there is no direct evidence to dateof abiogenic petroleum (liquid crude oil and long-chainhydrocarbon compounds).

Geologists now consider the abiogenic formation of

petroleum scientifically unsupported, and they agree thatpetroleum is formed from organic material.

However, the abiogenic theory can't be dismissed yet becausethe mainstream theory still has to be establishedconclusively..


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The word petroleum means literally rock oil. It was thought to be a completely different oil

than that which comes from vegetable sourcessuch as the olive, but modern research has

traced its origin to the lipids (oils) of planktonic(free floating) plants and animals which live inbrackish water such as blue-green algae andforaminifera.

The brackishness is essential because aerobic

bacteria does not live in brackish water. Aerobic bacteria would decompose all of the

organic matter.


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In brackish water the organic matter of theplanktonic plants and animals sinks to thebottom and is incorporated in clay sedimentswhich ultimately become sedimentary rocks.

This is the origin of the oil shales.

Under high pressure and temperature the oilof clay shales can be squeezed out into

porous rock. In porous rock the oil can traveluntil it reaches an impervious barrier such asa salt dome.


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Also millions of years ago bodies of plants andanimals which are rich sources of hydrocarbonsgot burried in the deep layers (But upper layarsnot very deep) of Earth.

There due to pressure of earths surface andsome geological catalysts, metallic oxides etc.thefossils of plants and animals got converted intomineral oil with high % of hydrocarbons.

About 150 years ago humans discovered thisvaluable energy source, which can be drilled outfrom earths surface layers.


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The evidence for the organic origin ofpetroleum is overwhelming:

Petroleum is found only in association withsedimentary rocks. There is no petroleum

associated with igneous or metamorphicrocks.

Polarized light passing through allpetroleums undergoes a rotation that is the

same as for the organic oils. Chlorophyll and hemin are found in

petroleum.


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http://www.sjsu.edu/faculty/watkins/petrorigins.htm

http://en.wikipedia.org/wiki/Abiogenic_petroleum_origin

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Petroleum Origin Neeraj