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How Oil Is Formed

  1. Jul 29, 2011 #1
    Quote :
    Oil is commonly formed in rock or in sealed pockets under the seabed and it is from the Latin for ‘rock oil’ that the word ‘Petroleum’ is derived, though this umbrella term also covers natural gas as well as oil.

    What we commonly refer to simply as ‘oil’ is properly known as mineral oil or crude oil and is formed from plant and animal matter that has broken down and been subjected to extremes of temperature and pressure over millions of years.

    It is true that the Oil is formed from plant and animal instead of Dinosaur?
     
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  3. Jul 29, 2011 #2

    Evo

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    Last edited by a moderator: Apr 26, 2017
  4. Jul 31, 2011 #3
    D'uh, dinosaurs were animals, too...
     
  5. Aug 1, 2011 #4
    While squeezing a lemon the other day, I noticed how oily the results were on my skin, even after a quick rinse. I'd always thought "lemon oil" used on furniture merely referred to the scent, but lemons apparently have a lot of actual oil in them.

    From what I understand, crude oil contains a wide variety of oil weights and types from pretty much all sources vegetable and animal.
     
  6. Aug 10, 2011 #5
    Oil is formed from plants and animals. Don't forget there are different types of oil as well.
     
  7. Aug 14, 2011 #6
    Interesting how the science changes. When I was in grade school, prevailing theory was that oil did originate from dead dinosaurs; a dinosaur still serves as the trademark of a well known oil company.
    Current theory is that micro-organisms are the source of oil.
    And then there is notion of abiogenic oil…
     
  8. Aug 14, 2011 #7

    DaveC426913

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    Yes, growing up I too learned that oil came from flattened dinosaurs.

    A bit of grown-up reflection on this reveals how silly it is. The biomass of all large animals is insignificant compared to the biomass of plants and microorganisms.
     
  9. Aug 16, 2011 #8

    Dotini

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    My family has been in the oil and gas business for over 90 years. My grandfather worked the Louisiana and Oklahoma oil patch as a brief rival to J Paul Getty, my father obtained his degree in geology and did field work in Texas for many years, and my brother is currently doing land and title work in Arkansas. And I still receive useful royalties from landwork and leasing I did in Texas during the late 70's and early 80's. Since then my work in the industry consists mainly in going to my mailbox and picking up my checks. However petroleum oil and gas oil is formed, I'm certainly appreciative and grateful for it.

    A few years ago I read a book by the noted scientist Thomas Gold called "The Deep, Hot Biosphere" which discussed abiogenic origin of oil. In checking with wikipedia, I note that this concept has not proven to be useful in finding new oil, so interest in it has waned.

    My questions:
    1) Is abiogenic oil formation a banned topic at PF?
    2) Is "Peak Oil" accepted as a fact at PF, or is it too a banned topic?

    Respectfully submitted,
    Steve
     
  10. Aug 16, 2011 #9
    There is no point in the the history of the oil industry, of which I am aware, when the consensus view was that oil was formed from dead dinosaurs. This appears to be the product of the same sloppy teaching that accords every cone shaped hill in the vicinity of a community the false identification as a volcano, or claims the interior of the planet is molten.

    The principle source of oil are the remains of microscopic animals which are converted to kerogen, from which hydrocarbons then migrate to reservoirs.
     
  11. Aug 16, 2011 #10
    http://en.wikipedia.org/wiki/Thermal_depolymerization" [Broken] from most organic materials so I think the answer is well known. There will always be oil as long as there is waste to convert and people willing to pay for it - even in a twenty five years when all the natural resource deposits have been exploited. (We are likely in the final doubling period for oil resources usage.) Manufactured or converted Oil will still be available and useful but it will be about $25 a gallon - mostly because of demand. It doesn't cost nearly that much to make oil.

    Some of the geologic oil deposits include dinosaurs - but most of it would be organic sediments. Anything that has died and settled to the bottom of a river delta or ocean bottom could end up as oil. Sometimes dinosaurs ended up in those sediments but dinaosaurs were far below 1% of all the sediment deposits organic volumes throughout all of prehistory.
     
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  12. Aug 17, 2011 #11
    Please provide an example of such a case - one would be sufficient - and provide citations that demonstrate a portion of the oil was derived from the dinosaur remains.

    To clarify, I believe your statements are incorrect, but am willing to be persuaded by evidence.
     
  13. Aug 17, 2011 #12

    DaveC426913

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    How would one go about giving such an example?

    "This oil deposit contains some dinosaur remains whereas that one does not."

    Your argument is that no oil deposits contain remains of dinosaurs. How will you defend that?
     
  14. Aug 17, 2011 #13

    Evo

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    I guess that it would be impossible to say that some remnant of a dinosaur could not have been washed out to sea and ended up mixed into oil, but it's highly unlikely.

    http://www.geotech.org/survey/geotech/Oil.pdf [Broken]
     
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  15. Aug 17, 2011 #14

    DaveC426913

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    Well, I'm not nitpicking about edge cases here, I mean is Ophiolite suggesting that - in principle - macrolife is simply not a normal component of oil deposits?
     
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  16. Aug 17, 2011 #15
    Ophiolite has pretty much knocked it out of the park from what I can gather. Basically, pond scum and anyother microscopic life rains down in the water collumn after death. They accumulate on the ocean floor as sediment and thus begins their decay. The process requires energy in the form of heat.

    So location in a tectonic zone or subsiding region definitely helps. As the sediment and rock are taken under to an area where the temperatures far exceed temperatures on the surface.

    Oil is found in deformed regions such as the Persian Gulf area from Baku to Tehran where oil is trapped by giant anticlines. Texas and Nigeria there are salt and shale tectonics respectively. However, tectonics are mainly factors in trapping oil.

    If I remember correctly, the bacteria that eat the dead creatures which produce oil are responsible for oils' various signatures.
     
  17. Aug 17, 2011 #16

    DaveC426913

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    And yet he claims that even "one example" of a deposit containing even "a portion" of dinosaur remains is against current understanding.

    Again, I'm not nitpicking here. I'm asking if macrolife decaying and forming a protion of the constituents of oil is simply not at all as we currently understand it.
     
  18. Aug 17, 2011 #17
    The pond scum (or whatever organic material) has to fall into anoxic water and thus be protected from decay in order to later form oil. If the pond scum decays, -no oil.
     
  19. Aug 17, 2011 #18

    turbo

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    Swamps, lagoons, etc that harbored simple life that could have ended up as the precursors to oil probably also harbored complex life (fish, crocodilians, reptiles, etc) which also joined the sediments at the bottom. If the water was anaerobic, then the macro-creatures didn't rot, either, and could have ended up being a part of what became oil. It pretty much all depends on at what era the oil precursor sediments were laid down.
     
  20. Aug 17, 2011 #19
    Icthyosaurs that were oceanic dinosaurs.

    Probably a few of them turned into oil for sure.
     
  21. Aug 22, 2011 #20
    The wording is that "some oil deposits contain dinosaurs". Perhaps I am too much of a literalist. Decaying organic material, generally microscopic animal life, deposited - as others have noted - in anoxic conditions is converted to kerogen. Such deposits are typically fine grained i.e. clays, which - through diagenesis - will go on to become claystones and shales. The kerogen then undergoes further chemical changes to release oil, which migrates into the oil reservoirs.

    General usage would have reserved the phrase 'oil deposits' for these oil reservoirs, not for the source rocks which are, not surprsingly, called source rocks, not oil deposits.

    Now it is entirely possible - indeed, I think a virtual certainty - that some of these reservoir rocks containing oil also contain dinosaur remains. But those dinosaurs are not the source of the oil that has migrated there. Equally, the occassional stray dinosaur, washed out to sea and sinking to the bottom where it is buried by a turbidity current deposit, may assuredly contribute its tiny mass to the developing kerogen.

    I, however, am unaware of such an event ever having been identified, not because it may not have occured, but because it would exceedingly rare. If it has been documented then I would really like to read about it. Hence I asked for a citation.

    for StuffIThink - Icthyosaurs are not dinosaurs.
     
    Last edited: Aug 22, 2011
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