A Basic Understanding of Oil

The creation of oil, gas, coal, and kerogen is an ancient process, which has taken place over the eons ever since photosynthetic life first occurred in the oceans and seas. For example, did you know that the Alberta oil sands area was once part of a prehistoric sea?

Alberta's oilsands are in an area that was once part of a prehistoric sea and have yielded several important marine reptile fossils. _CBC.ca

Oil creation is a renewable process, but over quite a long time span. Gas is made more quickly and more ubiquitously under the seabed than oil, and is becoming so cheap and common as to be thought of as a nuisance in many locations.

But it is crude oil about which such a fuss has been made for the past 100 years or so. And a well educated person should know more about crude oil than he is likely to find in the media or on the doomer sites. This embedded book by oil insider Leonardo Maugeri is likely to fill a lot of holes in the oil education of most ordinary people.

The Age Of Oil

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"The Age of Oil" by Leonardo Maugeri is a basic-level primer on the various facets of the modern petroleum age, from past, to present, and to future. It is best to start with basic history and basic supportable facts. Then, if you wish to go out on a limb, at least you will have a solid foundation from where to start.

Where oil comes from, and a hint of where new oil may be found

Looking at changes in atmospheric concentrations of O2 and CO2 over time is another way of noting the underlying biological processes involved in making the plants and microbes that go into making fossil fuels.

Oil shale sediments were deposited on large lake beds in the US western states:

Lacustrine sediments of the Green River Formation were deposited in two large lakes that occupied 65,000 km2 in several sedimentary-structural basins in Colorado, Wyoming, and Utah during early through middle Eocene time....The warm alkaline lake waters of the Eocene Green River lakes provided excellent conditions for the abundant growth of blue-green algae (cyanobacteria) that are thought to be the major precursor of the organic matter in the oil shale. _geology.com

How old is the oldest oil? No one knows, since it hasn't yet been found. But some oil has reportedly been found in rock that was billions of years old. Photosynthetic life has been around almost 3 billion years, so that provides for a lot of oil creation in deep rock layers.

Geologists usually don't bother looking for oil in very ancient (Precambrian) rocks for two reasons:

Conventional wisdom insists that oil is derived almost exclusively from organic matter, and additional conventional wisdom assures us that life was exceedingly scarce on earth billions of years ago.

Any oil that was created billions of years ago would have surely been destroyed by intense pressures and high temperatures over the eons.

Yet, Precambrian oil in commercial quantities has been found in formations up to 2 billion years old (in Siberia, Australia, Michigan, for example). While some of this oil might have migrated in-to the Precambrian rocks from younger source rocks, some of it does seem indigenous and, therefore, ancient.

...Now, three Australian scientists (R. Buick, B. Rasmussen, B. Krapez) have discovered tiny nodules of bitumen (lumps of hydrocarbons) in sedimentary rocks up to 3.5 billion years old in Africa and Australia. These bitumen nodules were formed when natural hydrocarbons were irradiated by radioactive isotopes that coexisted in the ancient rocks. Futhermore, these African and Australian rock formations were never severely deformed or subjected to high temperatures. The possibility exists, therefore, that some of the earth's oldest rocks may contain substantial oil reserves. So far, no one has seriously looked for oil in Precambrian rocks because of the two preconceptions noted above. _Science-Frontiers

The planet has gone through a large number of cycles over the past few billion years. Unless you can go back through time and trace the large numbers of optimal areas for oil, gas, coal, kerogen, and bitumen formation which have come and gone, come and gone, come and gone -- and been hopelessly changed and disguised by ongoing geologic processes -- you may be easily persuaded that almost all the fossil fuels have already been found.

The "abiotic oil" concept is not discussed here because the concepts behind biotic oil are difficult enough for most people to understand. And most hydrocarbons produced in the mantle by abiotic processes are shorter chain hydrocarbons, as you might find in "wet gas." Biotic and abiotic hydrocarbons tend to mix in the crust and follow much the same routes of migration upward in many cases. But if you want a good example of quick renewable hydrocarbons, the abiotic variety might qualify.

Ancient Oil and Mass Extinctions: Can We Connect the Dots?

Expansion to Extinction Over Last 540 Million Years
Mass extinctions have played an important role in the evolution of Terrestrial life. With each mass extinction, the way is cleared for the spread and adaptation of surviving species, and for the emergence of new species. But that is not what we will talk about today.

Recent findings in geochemistry have called into doubt some of the pet theories of climate scientologists scientists concerning acid oceans and mass ocean extinctions. Here is the abstract from the paper in PNAS:

Periods of oceanic anoxia have had a major influence on the evolutionary history of Earth and are often contemporaneous with mass extinction events. Changes in global (as opposed to local) redox conditions can be potentially evaluated using U system proxies. The intensity and timing of oceanic redox changes associated with the end-Permian extinction horizon (EH) were assessed from variations in 238U/235U (δ238U) and Th/U ratios in a carbonate section at Dawen in southern China. The EH is characterized by shifts toward lower δ238U values (from -0.37‰ to -0.65‰), indicative of an expansion of oceanic anoxia, and higher Th/U ratios (from 0.06 to 0.42), indicative of drawdown of U concentrations in seawater. Using a mass balance model, we estimate that this isotopic shift represents a sixfold increase in the flux of U to anoxic facies, implying a corresponding increase in the extent of oceanic anoxia. The intensification of oceanic anoxia coincided with, or slightly preceded, the EH and persisted for an interval of at least 40,000 to 50,000 y following the EH. These findings challenge previous hypotheses of an extended period of whole-ocean anoxia prior to the end-Permian extinction. _PNAS

More information on the study

The suggestion is that the ocean anoxia was secondary to the main extinction event, rather than being the cause. More study will be necessary to validate the isotopic techniques utilised. But this finding cannot but be a disappointment to the politically correct denizens of deep climate scientology science.

But what interests Al Fin know-it-all-o-tologists about this information, is how it may relate to the topic of the production and sequestration of ancient oil. Deep ocean anoxia is not only related to mass extinction events, it is also a component of oil formation in the deep seabed.

Sea bottom anoxia occurs routinely at the mouths of large rivers, where massive sediment routinely buries dead sealife that is constantly deposited on the seafloor. That is why rich oil fields are often found offshore of large river deltas -- either where the deltas are now, or where they were hundreds of millions of years ago.

An ancient oil sleuth must be able to backward-trace the movements of continents and great river valleys, in order to know where to look for such sediment-buried deposits.

Another cause of mass sediment burial of seafloor organic material, is massive volcanic activity. This would be particularly important to an ancient oil sleuth when a group of volcanoes might stay active for millions of years, in the same general vicinity upwind of river deltas or rich upwelling currents.

But in cases of mass extinctions, the large scale deep ocean anoxia occurring at the same time as massive deposition of organic material onto the seafloor, might be a particularly rich time for the initiation of large scale oil production.

When this process occurs over continental crust, the oil can be preserved for a very long time. If it occurs over oceanic crust, the oil may be subducted with the crust into the mantle, where it will likely be converted into short chain hydrocarbons, CO2, CO, and other forms of carbon. The short chain hydrocarbons may return to the crust, and may eventually be recovered economically. Diamond and graphite may also return to depths which allows humans to recover them economically.

Regardless, it is the ancient oil we are interested in. The challenge is to connect the extinction events, the ocean anoxia, and the ancient geographic patterns together, to provide the best guess for the locations of giant oil deposits which might conceivably still exist in an undiscovered, but ultimately recoverable state.

Humans have become accustomed to utilising the easy oil, and are just now getting good at recovering oil from the harsh, deep ocean environments. That is a good thing, because the Earth is 70% ocean-covered.

Still, some the planet which was once covered by oceans is now dry land, and such places -- if they fit the criteria above -- might be some of the first locations to check out.

First published at Al Fin, the Next Level
Postings from Al Fin blog on "Oil from ancient seas"

Do We Really Want to Consume All of These Geo-Hydrocarbons?

The doomsayers of the 1970s thought we would have run out of oil by now because they compared knowledge about the state of supply then with rates of consumption then, and concluded that those available supplies would soon be exhausted. But we have consumed 40 more years’ worth of oil since then and yet find ourselves with more reserves than we believed we had in 1970.

That is possible because the supply of oil isn’t only what is in the earth’s crust. Supply is also determined by the application of human intelligence to the problem of finding the oil we need. Today’s extra reserves are not due chiefly to discoveries of new deposits, but from wringing more supply from already known reserves through enhanced recovery techniques.

...We are nowhere near to running out of natural resources. Human creativity and financial resources together will ensure a continued supply of all the resources we need. The exact form those resources will take cannot be known today, however. It relies on future innovations, which are, by their nature, unpredictable because they will be the fruit of our imagination and curiosity. That is why the human mind is the greatest natural resource of all. _FP

IEA 2008 Taken from CSIRO 2011 (PDF)
It is only a matter of time before fuels produced from agricultural, forestry, municipal waste, marine biomass, and microbial production become cost competitive with geo-hydrocarbons. Since such renewable fuels can be produced virtually anywhere on the inhabited parts of the planet, once the infrastructure is in place to produce economically competitive renewable liquid fuels, the need for geo-hydrocarbons is likely to shrink steadily, for all parts of the world except for those regions capable of very cheap production of geo-hydrocarbons.

From Data in Rogner 1997 (PDF) via GWPFLikewise, for electricity production, the development of advanced fission reactors which are safer, cleaner, cheaper, more scalable in production, less prone to proliferation and storage hazards, and capable of burning fuel much more thoroughly -- these newer reactors will make the use of coal, gas, and oil for power production virtually obsolete except for areas rich in geo-hydrocarbons which are unable to afford or operate nuclear reactors. If scalable fusion and LENR reactors become workable, the obsolescence of hydrocarbons for production of heat and power should be that much more complete.

The quantities of geo-hydrocarbon pictured in the graphs above are almost certainly gross underestimates -- and it is likely that to some extent "wet gas" is produced on a quasi-renewable basis deep in the crust or in the upper mantle of the planet. Some of that gas may even migrate to upper levels to become economically recoverable. And some of those "renewable" short-chain geo-hycrocarbons may be converted by bacteria into a crude oil, deep in the crust. If so, estimates of Earth's geo-hydrocarbon complement are hugely underestimated by virtually every published source.

CSIRO_2011 (PDF)
We can find clean and affordable ways to use most of these geo-hydrocarbons, certainly. But the plain truth is that we should not have to. We are developing enough alternatives so that we will not require these resources, most of which should remain in place for the time should humans ever go back to a more primitive, more Luddist age.

Substituting renewable synthetic liquid fuels for conventional transportation fuels, and nuclear powered electricity and heat for power from coal and gas, will allow for a relatively smooth transition from geo-hydrocarbons to fuels and energy that will take us at least to the next millenium.

And if we ever do need the geo-hydrocarbons? There will be more in place then, than there were 200 years ago.

Deep Earth Hydrocarbons of Abiotic Origin

Scientists at Lawrence Livermore National Laboratory used supercomputers to simulate what would happen to carbon and hydrogen atoms buried 40 to 95 miles beneath the Earth’s crust, where they would be subjected to prodigious pressures and temperatures.

They found at temperatures greater than 2,240 degrees F and pressures 50,000 times greater than those at the Earth’s surface, methane molecules can fuse to form hydrocarbons with multiple carbon atoms. Interactions with metal or carbon sped up the fusion process, the researchers said. These conditions are present about 70 miles down, according to an LLNL news release. _PopSci

PO
A team of scientists and engineers from UC Davis, Lawrence Livermore Labs, and Shell Projects and Technology have created sophisticated simulations which demonstrate that methane can be polymerised to multi-carbon chains under conditions similar to those in the deep crust and mantle of Earth. (Published in PNAS)

...hydrocarbons of purely chemical deep crustal or mantle origin (abiogenic) could occur in some geologic settings, such as rifts or subduction zones said Galli, a senior author on the study.

"Our simulation study shows that methane molecules fuse to form larger hydrocarbon molecules when exposed to the very high temperatures and pressures of the Earth's upper mantle," Galli said. "We don't say that higher hydrocarbons actually occur under the realistic 'dirty' Earth mantle conditions, but we say that the pressures and temperatures alone are right for it to happen.

Galli and colleagues used the Mako computer cluster in Berkeley and computers at Lawrence Livermore to simulate the behavior of carbon and hydrogen atoms at the enormous pressures and temperatures found 40 to 95 miles deep inside the Earth. They used sophisticated techniques based on first principles and the computer software system Qbox, developed at UC Davis.

They found that hydrocarbons with multiple carbon atoms can form from methane, (a molecule with only one carbon and four hydrogen atoms) at temperatures greater than 1,500 K (2,240 degrees Fahrenheit) and pressures 50,000 times those at the Earth's surface (conditions found about 70 miles below the surface). _PO

More information in an earlier AFE posting

Abundant Hydrocarbons Buried Underground: Out of Sight Out of Mind

Oil&GasGeology_via_BitToothEnergy
Bit Tooth Energy blog takes a fascinating look at petroleum creation and deposition at various depth, using the Eagle Ford shale play as an example.

As a rough rule of thumb down to 15,000 ft the hydrocarbon is more likely to be oil, (which is thus referred to as the Oil Window) and below that it is more likely to be gas. That is only a rough rule of thumb, and one must remember that over time there has been a lot of uplifting and eroding, so that 15,000 ft isn’t necessarily what it used to be.

And the Eagle Ford shale is a fairly good example of this. If we use the EIA map of the play you can see that in the North, where the reservoir is about 6,000 ft deep the hydrocarbon is oil, while further South, where the deposit is down at around 14,000 ft then the hydrocarbon is dry gas. And in between it is what is known as a wet gas.

...You may note that the condensate from the wells in the wet gas zone have produced around 2.3 million barrels, while there has only been about 1.6 million barrels of crude produced. It is also worth noting that while the natural gas coming from the formation has been twice the equivalent volume of oil, the market for natural gas, at the moment is still down at around $4.6 per kcf, which using the Apache conversion, would give it a price of around $27.60 a barrel of oil equivalent. On the other hand the condensate is a light high quality product, and West Texas Intermediate crude is running at the moment at around $88.30 a barrel. _BitToothEnergy

The Bit Tooth article above talks about petroleum as coming from 500 million years of algal deposition in sediment, and conversion at depth -- heat and pressure -- to petroleum. The deeper the sediment, the more likely to be converted to gas, according to the source.

Now, if you look at the timelines provided above, you should note that photosynthetic organisms have been converting massive quantities of CO2 into organic carbon for over 3 billion years. The graphic below provides the mirror image of that process -- the production of atmospheric O2 juxtaposed by the evolutionary time of origin for various photosynthetic organisms.

Oxygen is a waste product of photosynthesis, and organic carbon is the main product. Rapid production of oxygen should correspond to a rapid production of organic carbon -- which was then buried in sediments. Whether this organic carbon became coal, kerogen, bitumen, petroleum, or other hydrocarbon resource, would depend upon where it ended up in the Earth's crust, or perhaps, mantle.

Recent science suggests that short chain hydrocarbons in the mantle are capable of surviving for significant periods of time at high pressure and temperature, perhaps later to migrate into the crust. These mantle hydrocarbons may have been subducted into the mantle via oceanic crust, or may be generated abiotically within the mantle itself.

The important thing to understand, is that massive quantities of organic carbons have been buried in the Earth for over 3 billion years. They no doubt exist in a wide variety of forms, from minimally altered to partially transformed to fully transformed, etc. Some of this carbon was no doubt oxidised to CO2 in the mantle and released into the atmosphere for recycling. Some of it no doubt seeped into the biosphere and was metabolised by microbes.

It is highly unlikely that humans have even begun to account for most of this missing organic carbon. Most of it will not be economically recoverable in any form. But we will not actually know that until we look for it, and find it.

Can Hydrocarbons Survive in the Hot, Pressured, Mantle?

The mantle is a dense, hot layer of semisolid rock approximately 2,900 kilometers thick. The mantle, which contains more iron, magnesium and calcium than the crust, is hotter and denser because temperature and pressure inside Earth increase with depth. Because of the firestorm-like temperatures and crushing pressure in Earth’s mantle, molecules behave very differently than they do on the surface. _Source

Earth's hydrocarbons are typically formed when organic matter is trapped in sediments on the bottom of Earth's oceans, seas, lakes, swamps, and bogs. Over a period of time, exposed to varying temperatures, pressures, and anaerobic conditions, the organic matter is transformed into hydrocarbons such as natural gas, peat, coal, and oil of various types.

Sediments trapped in oceanic crust (as opposed to continental crust) are subducted into the Earth's mantle after dozens of millions of years -- and exposed to very high pressures and temperatures. Many geologists had presumed that any hydrocarbons that had not migrated out of these subducted sediments, would be destroyed in the oxidising environment of the mantle. But a variety of research over the past several years suggests that not only can hydrocarbons survive the heat and pressure of the upper mantle -- new short-chain hydrocarbons may actually be created within the mantle.

... conventional geochemists argued that hydrocarbons could not possibly reside in Earthʼs mantle. They reasoned that at the mantleʼs depth—which begins between 7 and 70 kilometers below Earthʼs surface and extends down to 2,850 kilometers deep—hydrocarbons would react with other elements and oxidize into carbon dioxide. (Oil and gas wells are drilled between 5 and 10 kilometers deep.) However, more recent research using advanced high-pressure thermodynamics has shown that the pressure and temperature conditions of the mantle would allow hydrocarbon molecules to form and survive at depths of 100 to 300 kilometers. Because of the mantleʼs vast size, its hydrocarbon reserves could be much larger than those in Earthʼs crust. _PDFLivermoreLabPDF

“The notion that hydrocarbons generated in the mantle migrate into the Earth's crust and contribute to oil-and-gas reservoirs was promoted in Russia and Ukraine many years ago. The synthesis and stability of the compounds studied here as well as heavier hydrocarbons over the full range of conditions within the Earth's mantle now need to be explored. In addition, the extent to which this 'reduced' carbon survives migration into the crust needs to be established (as in, without being oxidized to CO2). These and related questions demonstrate the need for a new experimental and theoretical program to study the fate of carbon in the deep Earth,” the expert adds. _Softpedia

Now for the first time, scientists have found that ethane and heavier hydrocarbons can be synthesized under the pressure-temperature conditions of the upper mantle -the layer of Earth under the crust and on top of the core. The research was conducted by scientists at the Carnegie Institution's Geophysical Laboratory, with colleagues from Russia and Sweden, and is published in the July 26, advanced on-line issue of Nature Geoscience. _Geology.com

So far there is no strong evidence that large quantities of economically important hydrocarbons are being generated within the mantle, with subsequent migration up into the crust -- where humans can access them. But it seems quite likely that new gaseous hydrocarbons do migrate from the mantle into the crust -- in some quantities -- and contribute to gas deposits of various types, including methane clathrates.

What is more interesting to me than the abiotic generation of hydrocarbons is the fate of billion year old hydrocarbons of biological origin which find their way into the upper mantle through geologic upheaval. No doubt some of this hydrocarbon will survive as medium chain alkanes, although I suspect most will end up as methane or ethane. Some will get caught up in volcanic activity and be converted to CO2 -- or get ejected into the atmosphere or ocean as CH4. But what is the proportion of each product? How much will end up in a typical oil & gas "trap" in the crust where they can be economically extracted?

We will learn more about that over time. But between the abiotic gases and the truly ancient hydrocarbons that have survived the eons, it is likely that there is far more hydrocarbon in the deep Earth than geologists typically allow themselves to dream.

More: A rare, optimistic view of energy from the NYTimes