How Oil Is Formed

Evo

Crackpot conspiracy theories having to do with abiogenic oil are abundant on the internet.

Here's a paper on it.

http://static.scribd.com/docs/j79lhbgbjbqrb.pdf

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Actually, I am not sure that it is correct to say that abiotic oil formation is all crackpottery. It is beyond imagination that, somewhere, there are just the right conditions for hydrocarbons to form. After all, we find such a vast range of other materials of awe-inspiring unlikeliness that this seems almost inevitable.

The key is the issue of commercially available. I am confident that any 'reserves' that are exploited by humans is from biogenesis. I'd guess that hydrocarbons from 'abiotic' sources are in such small quantities that it is likely implausible to distinguish them from biological contaminations. (Maybe I'll be corrected on that assumption?)

Evo

No, it's crackpot conspiracies that the US government invented fossil fuels to hide the fact that oil is plentiful and an undepletable resource.

You haven't seen the posts I've deleted.

robert2734

To produce oil the plants and animals have to be buried into a window of 5000 to 10000 feet. Any deeper than that and they become natural gas.

Dotini

http://www.bbc.co.uk/news/science-environment-15458636

A thought provoking report on recent research which "complicates the picture of how carbon and complex organic molecules may end up travelling into other solar systems such as our own."

http://www.nature.com/nature/journal...ture10542.html
Unidentified infrared emission bands at wavelengths of 3–20 micrometres are widely observed in a range of environments in our Galaxy and in others1. Some features have been identified as the stretching and bending modes of aromatic compounds2, 3, and are commonly attributed to polycyclic aromatic hydrocarbon molecules4, 5...

...This structure is similar to that of the organic materials found in meteorites, as would be expected if the Solar System had inherited these organic materials from interstellar sources.

http://www.gizmag.com/organic-stardu...covered/20310/
"The researchers say the substances generating these infrared emissions actually have chemical structures that are so complex that their structure resembles those of coal and petroleum. Since coal and petroleum are remnants of ancient life and this type of organic matter was only thought to arise from living organisms, the researchers say this suggests that complex organic compounds can be synthesized in space even when no life forms are present."


As an oilman and royalty owner, motorist and two-stroke racing engine operator, I'm glad of having oil no matter where it comes from - even if it's from the stars.

Respectfully submitted,
Steve

Ophiolite

It is unfortunate that abiotic petroleum as a concept, despite sensible work by Gold and decades of work by the Russians, was largely hijacked by the lunatic fringe. A more dispassionate examination of the facts reveals some interesting possibilities.

As Dotini notes with his links organic compounds are abundant in space. Whether we are talking comets, meteors, giant molecular clouds or accretion discs, the universe is rife with them. As of five or so years ago over one hundred distinct organic compounds had been identified, including the PAHs noted in the Nature article and amino acids in meteorites.

Now these are the very things from which planets, including the Earth are made, so we may expect a substantial total mass of carbon to be present within the Earth. The carbon content of the crust is wholly indequate to account for the mass of carbon that must be present if we are correct in the belief that the Earth is on average of chondritic composition.

This means the mantle is a very large reservoir of carbon. The ubiquity of carbon dioxide in volcanic eruptions and diamonds carried from below in kimberlite pipes confirms that there is at least some mass present.

I find it entirely plausible that over time a proportion of this carbon may migrate upwards, continuing the devolatisation of the mantle thats been proceeding apace for four billion plus years. With the right pressure and temperature conditions obtaining complex hydrocarbons could then form.

While the total volume is potentially large speculation that its migration is rapid on a human time scale, so that reservoirs could refill in a lifetime, seem much less plausible.

My own opinion, based on occassional study of the topic and a working life spent in the oil and gas industry, is that substantial volumes of abiogenic petroleum may well have been produced over geological time - indeed I would be somewhat surprised if they had not - however, equally substantial, or greater volumes have been generated in what we see as the conventional way.

I repeat my opening assessment that it is unfortunate the concept got hijacked since it discourages research that might be able confirm, falsify, or at least shed some much needed light on the topic.

John L

It just seems like the deeper we drill, the more oil/natural gas we discover. How did all those plants and critters manage to make the journey that deeply into the planet short of subduction. And how many trees, or ferns, does it require to make one barrel of crude? And with all the billions of barrels of oil used already, shouldn't we already have run out of deat trees and ferns?

Heres something else: if the ocean sequesters huge amounts of carbon, which in turn is ingested by tiny critters, which die and sink to the ocean floor, and are eventually carried into the inner earth, along with water(again, subduction), why isn't it possible to convert all this mixture into hydrocarbons, which eventually try to complete the cycle by seeping back to the surface?

After all, isn't that part of the carbon cycle?

Evo

Sounds like you need to learn the basics.

http://www.geotech.org/survey/geotech/Oil.pdf

Ophiolite

This is not the case at all. Most oil reservoirs are between 3,000' and 10,000'. As temperatures rise the complex hydrocarbon molecules break down and we are left, largely, with methane. Oil is rarely found below 15,000'.

Remember that oil is primarily formed from dead critters not dead plants. Dead vegetation tends to produce coal. And they found their way to moderate depth by being buried under more sediments. Ultimately you are correct, in that the subsidence that provided space for deposition and the uplift that provide material to erode and be transported both occured because of plate tectonics.



I don't have a specific number to give you, but just remember we have practically exhuasted, in less than two hundred years, a quantity of oil that took several hundred million years to accumulate.

They appear to come out as carbon dioxide, not as complex hydrocarbons, but see my earlier post above.

mdemonion

It is said that oil can be found in large amount in Saudi Arab, Dubai side by digging under the earth..oil can be made from many ways..By various seeds like groundnut,sunflower and other,the oil is extracted..

CaptFirePanda

Based on various studies (including, but not limited to, studies by Giulia Galloi at UC Davis, et al) there is the possibility of an abiogenic source of hydrocarbons (work being done out of the Deep Carbon Observatory)

The idea that abiogenic, mantle-derived hydrocarbons are produced at a rate that would sustain our consumption, or exist in volumes that are economically viable, is likely not valid (Abiogenic Origin of Hydrocarbons: An Historical Overview; A review of the occurrence and origin of abiogenic hydrocarbons in igneous rocks)

Thus, it is likely that abiogenic hydrocarbons do exist to some degree, but they are not the panacea many might have you believe.

simonwar

I would suggest that http://gasresources.net is thoroughly investigated.

Thermodynamically oil will degrade over time to its constituent parts - to remain stable it requires pressures above 30Kbar + and high temperatures similar to those found at the level of the mantle.
This simple logic defies the theory of oil formation by biogenic synthesis over time in that:
Biological detritus does not exist at basement rock levels, liquids/gases will not flow from an area of low pressure to high pressure but rather the opposite.
After millions of years the oil deposits would have broken down to constituent parts IE followed the laws of thermodynamics changing from a state of high energy to a state of low energy.
This also points to the fact that hydrocarbons are being produced spontaneously at the level of the mantle not slowly as oil pundits would have us believe.

Ophiolite

This is a misleading statement. Complex hydrocarbons are formed from simpler components only under these conditions. Metastable hydrocarbons formed from more complex molecules are perfectly feasible.

For a comparatively recent assessment of the topic this 2006 paper is excellent. In relation to the issue of biogenic formation, the only part of the anti-biogenic argument I ever thought had any potential merit, here is a relevant extract:

A particularly contentious issue in this regard is whether higher hydrocarbons can be formed from oxidized organic molecules such as carbohydrates (C6H12O6) which are the dominant constituents of plants. As noted earlier, formation of higher hydrocarbons from oxidized organic molecules such as carbohydrates (C6H12O6) is not thermodynamically favourable under any conditions (Kenney et al., 2002). However, only 0.01-0.1 % of organic matter enters the biological carbon cycle (Schaefer, 1999). Petroleum is therefore not formed directly from plant material but mainly from type II kerogens which are derived from the low-temperature (<50°C) diagenesis of planktonic organisms and are rich in hydrogen and poor in oxygen (Tissot and Welte,1984; Klemme and Ulmishek, 1991; Schaefer, 1999; Berner, 2003). This is consistent with the formation of petroleum hydrocarbons from marine shales.

Glasby, G.P. "Abiogenic Origin of Hydrocarbons: An Historical View" RESOURCE GEOLOGY, vol. 56, no. 1, 85–98, 2006

betzalel

As most are aware a large mars sized object struck the earth roughly 500 million years after the formation of the solar system. The impact formed the moon and stripped the planet’s mantel of most of the volatile lighter elements. As 70% of the planet’s surface is covered by water a natural question to ask is: Where did the water come from, as the earth’s mantle contains almost no water or hydrocarbon?

There are two theories to explain how water and hydrocarbons came onto the earth: the late veneer theory and the deep CH4 theory. The late veneer theory hypotheses that comets struck the early earth after the big splat event covering the very hot earth with hydrocarbons. There are multiple problems with that hypothesis (See Thomas Gold’s Book Deep Hot Biosphere for details.)

One issue with the late veneer hypothesis is the observation that the percentage of gaseous isotopes in the earth’s atmosphere does not match that of comets (Comets are residues of the early solar systems. The comet elemental composition does match that of the sun). The late veneer theory’s explanation for the miss match of isotopes in the earth’s atmosphere to that of comets is that the early solar system had a close encounter with another solar system which temporary provided a limited source of comets to cover the earth but not significantly change the element composition of the sun.

The second hypothesis is the deep earth hydrocarbon theory. This theory hypothesizes that massive amounts of hydrocarbons (5% of the total core mass) are located in the earth’s core. As the core cools these hydrocarbon (CH4) are released. At very high pressures the CH4 forms longer chain molecules.

See Carnegie Institute of Sciences Deep Carbon Workshop presentations if you interested in this subject. (I will provide a link to that set of lectures when I have ten posts.)

The release of CH4 is still occurring as the upper surface of the ocean is saturated with CH4 which may indicate that CH4 is being released from some source. Perhaps the deep earth methane hypothesis could explain why there are massive amounts of methyl hydrates in the deep ocean and in permafrost regions.

betzalel

The deep earth hydrocarbon hypothesis could perhaps explain the super large oil and natural gas fields. Saudi Arabia for example has 25% of the planet’s oil reserves half of which is contained in only eight fields. Half of Saudi Arabia production comes from a single field the Ghawar.

Excerpt from this wikipedia article on Oil Reserves

Also from wikipedia:

Natural gas is interesting in the amount of new very large discoveries of natural gas in deep fields.


The following is an excerpt from Thomas Gold’s book the Deep Hot Biosphere which that outlines some of the observations he believes supports an abiogenic origin (non-biological, primeval origin), for petroleum and natural gas.


(1) Petroleum and methane are found frequently in geographic patterns of long lines or arcs, which are related more to deep-seated large-scale structural features of the crust, than to the smaller scale patchwork of the sedimentary deposits.

(2) Hydrocarbon-rich areas tend to be hydrocarbon-rich at many different levels, corresponding to quite different geological epochs, and extending down to the crystalline basement that underlies the sediment. An invasion of an area by hydrocarbon fluids from below could better account for this than the chance of successive deposition.

(3) Some petroleum from deeper and hotter levels almost completely lack the biological evidence. Optical activity and the odd-even carbon number effect are sometimes totally absent, and it would be difficult to suppose that such a thorough destruction of the biological molecules had occurred as would be required to account for this, yet leaving the bulk substance quite similar to other crude oils.

(4) Methane is found in many locations where a biogenic origin is improbable or where biological deposits seem inadequate: in great ocean rifts in the absence of any substantial sediments; in fissures in igneous and metamorphic rocks, even at great depth; in active volcanic regions, even where there is a minimum of sediments; and there are massive amounts of methane hydrates (methane-water ice combinations) in permafrost and ocean deposits, where it is doubtful that an adequate quantity and distribution of biological source material is present.

(5) The hydrocarbon deposits of a large area often show common chemical or isotopic features, quite independent of the varied composition or the geological ages of the formations in which they are found. Such chemical signatures may be seen in the abundance ratios of some minor constituents such as traces of certain metals that are carried in petroleum; or a common tendency may be seen in the ratio of isotopes of some elements, or in the abundance ratio of some of the different molecules that make up petroleum. Thus a chemical analysis of a sample of petroleum could often allow the general area of its origin to be identified, even though quite different formations in that area may be producing petroleum. For example a crude oil from anywhere in the Middle East can be distinguished from an oil originating in any part of South America, or from the oils of West Africa; almost any of the oils from California can be distinguished from that of other regions by the carbon isotope ratio.

Ophiolite

I think you meant to say 50 million years.



This is a more complex issue than you seem to think. The purported mismatch was based upon the analysis of isotope date from a handful of comets. However, isotope data from meteorites, specifically carbonaceous chondrites gave a passable match. More recently analysis of Hartley II ratios gave a good match. So, currently there is every indication that water could have been delivered by comets, asteroids, or both. The evidence is not an issue.

The core? Are you sure? I thought Gold, quite reasonably, pointed to the mass of carbon that should be present in the mantle. I don't think carbon is a siderophile.

What's wrong with decomposition of marine organisms as a source?

betzalel

Agreed. The big splat hypothesis assertion is that a Mars sized object struck the earth 50 millions after the formation of the earth.


No agreement. 70% of the earth's surface is covered by water, 4.5 billion years after the formation of the earth. The early solar wind was roughly 300 times stronger than the current. The solar wind would have removed the water from the atmosphere of the hot earth. Carbon chondrites do not have sufficient water to provide the necessary water. As others have noted the late thin veneer hypothesis would have created a Venus like atmosphere on the early earth which the sun would have removed all water from.

Even if there was some mechanism to hold the water in the early earth's atmosphere the current solar wind removes hydrogen from the earth's atmosphere. If one extrapolates the loss the planet would not be covered by 70% water.


Yes. Gold states source of the CH4 is from the liquid core not the mantel. The CH4 moves through the mantel picking up heavy metals which are present in heavy oil. As Gold notes disconnected oil field over large regions have the same significant heavy metals. If oil formed in situ there would be no heavy metals in the oil. (there are no heavy metals in the sedimentary rock where the oil is found) and even if there were heavy metals in the region where oil is found, the amount of heavy metals would vary by location, as the amount of heavy metals varies by region. It is only by flowing long distances from the liquid core to outer crust for the oil to pick up the necessary heavy metals (explain the amount of heavy metals in the oil) and to explain the uniformity of the amount of specific heavy metals found in large regions where oil is found.


How does the high concentration of methyl hydrates appear in the permafrost regions? What is wrong with the deep CH4 hypothesis? i.e. pros/cons comparing all observations to the two hypothesis. (Late thin veneer hypothesis vs the deep core hypothesis.)

I have not seen any papers that propose the massive natural gas deposit on the planet are due to biological processes. The carbon in the CH4 is almost pure C12. If the source of the carbon has the early thin veneer it would have increased in C13 to cosmic rays striking the carbon in the early atmosphere. The are observations after observations that support the liquid core as the source for CH4.

The Alberta oil sands (54,000 square miles, is larger than the area of England). This heavy oil in this region has flowed to cover the sand. What is the biological source for hydrocarbon that can form and then flow to cover a region that is larger than the area of England?

The abiotic theory for the formation is the standard theory in the old Soviet Union. Russia now has the largest reserves of natural gas in the world. The Russians have developed extreme depth drilling equipment and have found massive large natural gas reserves at great depth.

The world reserves of natural gas have significantly increased year by year. Ten years ago companies were developing a natural gas import terminal at the Canadian port of Kitimat. Due to massive deep natural gas finds in the Canadian Rockies that terminal has been changed to an export terminal.