Oil Formation: From Ancient Life to Modern Resource

[wilsonb]

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?

 

[Evo]

Here you go.

http://www.scienceonline.co.uk/energy/nonrenewable.html

 

[Nik_2213]

D'uh, dinosaurs were animals, too...

 

[DoggerDan]

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.

 

[deepat]

Oil is formed from plants and animals. Don't forget there are different types of oil as well.

 

[GeorgeRaetz]

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…

 

[DaveC426913]

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.

 

[Dotini]

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

 

[Ophiolite]

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.

 

[PajoTheDwarf]

http://en.wikipedia.org/wiki/Thermal_depolymerization" 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.

 

[Ophiolite]

Some of the geologic oil deposits include dinosaurs -.

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.

 

[DaveC426913]

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.

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?

 

[Evo]

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?

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

 

[DaveC426913]

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

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?

 

[DrClapeyron]

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.

 

[DaveC426913]

Ophiolite has pretty much knocked it out of the park from what I can gather.

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.

 

[robert2734]

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.

 

[turbo]

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.

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.

 

[StuffIThink]

Icthyosaurs that were oceanic dinosaurs.

Probably a few of them turned into oil for sure.

 

[Ophiolite]

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.

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.

 

[Studiot]

Icthyosaurs are not dinosaurs.

Someone from nitpickersanonymous.org whispered in my ear

are not?

Where can I meet one? I thought I was the last living dinosaur left on the planet.

 

[Ophiolite]

Someone from nitpickersanonymous.org whispered in my ear

are not?

Speaking as a former student palaentologist I can assure you that icthyosaurs still are very definitely around and some stunning examples can be see at the Natural History Museum in South Kensington, London. :)

 

[DaveC426913]

Speaking as a former student palaentologist I can assure you that icthyosaurs still are very definitely around and some stunning examples can be see at the Natural History Museum in South Kensington, London. :)

Yeah. I think "are" implies "still alive".

You got news about a live ichthyosaur? I'd like to discuss it with you. Meet me in the back alley at midnight. Come alone.

 

[Ophiolite]

Yeah. I think "are" implies "still alive"..

To normal people, yes, but not to palaeontologists. I mean if they are alive they have all this squishy soft stuff that you have to remove to look at the bones.

 

[DaveC426913]

To normal people, yes, but not to palaeontologists. I mean if they are alive they have all this squishy soft stuff that you have to remove to look at the bones.

 

[wondering2]

I wonder if it is possible for the heat and presure at lower levels in the core can produce "oil" and "natural gas" without the need to bury small or large animals and plants several miles deep?

Just Wondering2

 

[cmb]

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.

In the form D-limonene, it is used [increasingly] as a solvent for other oily substances too, being much safer and environmentally benign than chlorinated hydrocarbons.

 

[cmb]

I wonder if it is possible for the heat and presure at lower levels in the core can produce "oil" and "natural gas" without the need to bury small or large animals and plants several miles deep?

Just Wondering2

There is a theory to this effect by a chap called 'Gold' I believe. If I find a link I'll post, but you'll likely have luck searching for 'Abiogenic Petroleum'.

 

[Dotini]

a chap called 'Gold'

Thomas Gold, eminent physicist (Cambridge, Harvard, Cornell), wrote "The Deep Hot Biosphere". A very good read.

Respectfully submitted,
Steve

 

[cmb]

Thomas Gold, imminent physicist...

...I'll be waiting to hear what he has to say, then, once he's a physicist!

 

[Evo]

There is a theory to this effect by a chap called 'Gold' I believe. If I find a link I'll post, but you'll likely have luck searching for 'Abiogenic Petroleum'.

To my knowledge the abiogenic oil hypothesis isn't accepted.

Abiogenic petroleum origin is a largely abandoned hypothesis that was proposed as an alternative to theory of biological petroleum origin.

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

 

[Dotini]

...I'll be waiting to hear what he has to say, then, once he's a physicist!

Thanks for so tactfully pointing out my spelling error. I have corrected it.

I have in my hand a carbonaceous chondrite, which I would like to throw at you.
http://en.wikipedia.org/wiki/Carbonaceous_chondrite

As for hearing what Gold has to say, you're a little late, since he died in 2004.

Respectfully,
Steve

 

[cmb]

_{(Sorry, Dotini, I could not resist that one!)}

 

[cmb]

So, just as an aside on this - a story line to some sci-fi story, maybe!...


Lovelock (Gia fame) has proposed what sounds to me like the only really practical way for carbon capture. This is to turn trees into charcoal (thus getting a little energy out of them to make it worth while) and then burying it.

As far as I can tell, this is the most practical way of doing it, so if we are going to do it, then, on the basis that the most practical things come to pass eventualy, then that'll eventually happen.

The 'story line', then, is that the coal we have today is the past attempt at carbon capture, by this method, of a civilization who left it too late to clean up their carbon emissions!

 

[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

 

[cmb]

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]

Actually, I am not sure that it is correct to say that abiotic oil formation is all crackpottery.

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 traveling into other solar systems such as our own."

http://www.nature.com/nature/journal/vaop/ncurrent/full/nature10542.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-stardust-discovered/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]

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?)

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 that's 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]

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?

Sounds like you need to learn the basics.

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

 

[Ophiolite]

It just seems like the deeper we drill, the more oil/natural gas we discover.

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'.

How did all those plants and critters manage to make the journey that deeply into the planet short of subduction.

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 occurred because of plate tectonics.

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?

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.

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?

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]

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 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 http://www.liv.ac.uk/~jan/teaching/References/Glasby%202006.pdfis 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

Saudi Arabia reports it has 262 gigabarrels of proven oil reserves (65 years of future production), around a quarter of proven, conventional world oil reserves. Although Saudi Arabia has around 80 oil and gas fields, more than half of its oil reserves are contained in only eight fields, and more than half its production comes from one field, the Ghawar field.

Also from wikipedia:

Qatar's proven natural gas reserves stood at approximately 896 trillion cubic feet (25.4 trillion cubic metres), that is almost 14% of all known natural gas reserves and the third-largest in the world behind Russia and Iran. The majority of Qatar's natural gas is located in the massive offshore North Field, which spans an area roughly equivalent to Qatar itself. Part of the world's largest non-associated natural gas field, the North Field is a geological extension of Iran's South Pars field, which holds an additional 450 trillion cubic feet (13 trillion cubic metres) of recoverable natural gas reserves.[1]

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]

As most are aware a large Mars sized object struck the Earth roughly 500 million years after the formation of the solar system. .

I think you meant to say 50 million years.

There are two theories to explain how water and hydrocarbons came onto the earth: the late veneer theory and the deep CH4 theory. ...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).

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 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.

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.

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.

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