This is from the always-interesting Whiskey and Gunpowder
It's a heavily
edited adaptation of two articles that can be found here in entirety:Peak Oil, Deep Oil: Part IPeak Oil, Deep Oil: Part II
By Byron W. King
SOME PEOPLE ARE just plain skeptical of the entire Peak Oil thesis. They believe that the deep crust of the Earth may hold untold quantities of oil and gas. The theory is that, at great depth, there are immense hydrocarbon resources just waiting for the driller's bit to find and deliver to the surface. It goes back to some scientific work that the Soviets performed in the 1930s, and more recently to the work of the late Thomas Gold, a former professor of astronomy at Cornell University.
The first principle in all of this is that the most abundant element in the universe is hydrogen. (The late Frank Zappa used to say that the most abundant element in the universe was stupidity, but this gets away from the subject).
This abundant hydrogen, goes the thinking, was the direct precursor for the petroleum that we find today in the crust of the Earth. The theory states that when our planet formed from primordial dust about 4.5 billion years ago, a large measure of elemental hydrogen was incorporated throughout its composition.
The sun is a big ball of (mostly) constantly fusing hydrogen. At its surface, the sun is exploding with the intensity of about a bazillion hydrogen bombs every second. (Somebody has surely figured out the exact number. For now, just assume it is a bazillion.) But the sun's own immense gravity keeps it all in some semblance of spherical balance, so all we receive here on Earth is the sun's light and heat radiation, plus certain other particles and waves.
The inner planets of the Solar System -- Mercury, Venus, Earth, and Mars -- are composed primarily of metals like iron and nickel and other forms of complex minerals and rock. (The mantle of the Earth is mostly olivine, in case you are wondering.)
The outer planets -- Jupiter, Saturn, Uranus, and Neptune -- are what are called "gas giants," with substantial components of hydrogen making up their composition. (Forget about Pluto and Planet X, which are not relevant just now.)
The cosmological theory is that, when the solar system was being formed, the gas from the inner regions was pulled by gravity inward toward the center to form the sun. Thus, the heavier matter, which did not get pulled inward, was left to form the inner planets that orbit the sun on the same planetary plane. The result is the four rocky inner planets, with their metal cores. The gas in the outer regions of the solar system was, over time, swept up by gravitational forces into the gas giants.
Enough of this. If you want more, watch Star Trek.
So according to the theory, a not insignificant amount of hydrogen was also incorporated into the formation of planet Earth. Over the intervening 4.5 billion years, this hydrogen has chemically reacted with metals and carbon, in various forms and at great depth within the Earth, to form methane gas and even more complex hydrocarbons, like oil. These volumes of gas and oil are supposed to have seeped upward into the continental crust over time, to where mankind now has accessed these oil and gas deposits by drilling.
The famous Russian chemist Dimitri Mendeleev, whose pioneering work led to the creation of the periodic table, was the first to propose what has been named the "Carbide hypothesis" to explain the origins of petroleum. Mendeleev's science makes a lot of sense, as far as it goes.
His assumption is that deep within the Earth there are compounds called metal carbides, which react with water in the form of hydrothermal solutions. In the most basic case, iron carbide plus water reacts to form iron oxide (better known as "rust") plus acetylene, the well-known industrial gas.
The acetylene molecule is composed of two carbon atoms and two hydrogen atoms. The two carbon atoms are tightly connected by three powerful electron bonds, hence the rather high energy state of acetylene. (This is why people use acetylene for metal-cutting purposes. Many years ago I worked as a welder and metal cutter. I know firsthand how hot acetylene can burn, particularly when a drop of molten steel falls down into your boot).
At elevated temperatures, such as are found deep within the Earth, acetylene polymerizes to form benzene and a complex mix of other "long-chain" and "aromatic" hydrocarbons. Presto, petroleum, goes the theory.
Cornell's Gold referred favorably to the Mendeleev work, and also proposed the well-known "Fischer-Tropsch reaction" as an additional mechanism for the formation of complex hydrocarbon molecules at depth. The chemistry is pretty straightforward. Carbon dioxide and hydrogen react to form carbon monoxide and water vapor. Add more hydrogen to the carbon monoxide, and the reaction creates methane gas and water vapor. Again, presto, methane.
Both of these chemical reactions, "metal carbide" and "Fisher-Tropsch," have been successfully demonstrated countless times under laboratory conditions. This type of chemistry is what backs up the claims by some people of the so-called "abiotic" origin of oil and gas. That is, goes the argument, oil and gas are not the highly refined organic remains of ancient life forms such as the well-known "dead dinosaurs." Instead, oil and gas are substances of almost primordial origins, rooted in the elemental hydrogen cloud out of which Earth formed 4.5 billion years ago.
In essence, according to the abiotic theory of origins for oil and gas, humankind can have almost unlimited amounts of hydrocarbon resources, if the oil industry could or would just drill deep enough wells. It all sounds so cracking good, but maybe we had better look into the properties of oil and gas and get into some of the science of geology.
True to prediction, deep Earth actually does produce abiotic methane. You can detect methane gas, in minute but measurable trace quantities, discharging from the world's midocean ridges, which are connected by volcanic vents to the Earth's upper mantle. Methane gas also can be found venting from some volcanoes, which are a connection between the Earth's surface and the high-temperature zones within the Earth's deep crust, if not its upper mantle. And there is even some small amount of methane gas in some hard rock deep mine shafts.
I do not mean coal mines, which tend to accumulate gas that vents from the coal seams. I mean hard rock mines dug into the deepest, hardest, and oldest granites, gabbros, and metamorphic rock facies you can imagine. There are no "dead dinosaurs" in these rocks, so something else is going on.
Obviously, the methane from midocean ridges, volcanoes, and hard rock mine shafts has to come from somewhere. And at least some of the evidence is that it comes from "down there," from deep within the Earth. So no one is denying the chemical possibility of the existence of abiotic methane welling upward from within the Earth. The dispute is whether or not there is evidence that abiotic methane is, or has ever been, produced in sizable quantities.
As with most things that are part of the oil business, you have to be ready to "think big." But at the risk of getting ahead of the story, the best evidence is that the amount of methane generated from deep sources within the Earth is exceedingly minor. It is certainly minor when compared with what one finds in what are considered commercial hydrocarbon deposits.
In addition, while there is some evidence of abiotic natural gas in the form of methane, there is next to no evidence to indicate the abiotic creation of the literally tens of thousands of complex hydrocarbon molecules that are found in crude oil.
It is one thing to perform a "Fisher-Tropsch" transformation and turn carbon dioxide and hydrogen into water vapor and humble methane gas. It is quite another thing for the chemistry behind the "metal carbide" and "Fisher-Tropsch" reactions to occur on a massive scale, if not on a planetary scale, creating vast quantities of abiotic natural gas, let alone oil, that seeps upward from the Earth's mantle or deep crust.
One good test to discriminate between an abiotic origin for hydrocarbon molecules, versus an organic origin ("dead dinosaurs," as noted above), gets into the field of stereo chemistry. If you took a decent high school biology class, at least before most U.S. high schools dropped such material from the curriculum because it took resources away from football programs, you may remember that most organic biological compounds are optically active.
That is, when you view optically active substances through a microscope, they tend to rotate a beam of polarized light. This has to do with a chemical concept called "chirality." Two molecules can have the exact same chemical composition, and include almost all other physical properties, but they are mirror images when it comes to the structure of the atoms that make up the molecules. The two mirror image compounds are called "enantiomers" of each other.
Biological synthesis almost always forms compounds that are "left handed" or "levorotary," and which rotate polarized light to the left. Whereas abiotic synthesis tends to produce samples of organic molecules that are equally "levorotary" ("left-handed") or "dextrorotary" (that is, the latter substances rotate polarized light to the right). Got it?
So with this bit of chemistry as background, what do we find out in nature? If oil or gas were truly of abiotic origin, samples viewed under a microscope with polarized light would tend to be half levorotary and half dextrorotary, because that is what happens under conditions of abiotic origin. But that is not what we find. Almost every sample of oil and gas ever analyzed has demonstrated levorotary properties, a statistic that leans decidedly toward ancient biological origin. That is, "dead dinosaurs."
What about those samples from the midocean ridges, volcanoes, and deep mine shafts? They too are almost all levorotary, although, in fairness, there are a few samples that have surprisingly large amounts of "dextrorotary" molecules as well. What is this telling us? Probably that while some of the carbon compounds that come from the deep regions of the Earth's crust or upper mantle are abiotic, most are recycled carbon from the surface. The mechanism for recycling the carbon is most likely subduction of the Earth's crust (a key concept in the field of plate tectonics) or deep penetration by hydrothermal solutions that carry down organic matter from above.
How deep into the Earth can material penetrate if it originated on or near the surface?
By way of answer, there was a recent article in Science
magazine, concerning garnet intrusions in diamonds. Diamonds are found in a type of geologic feature known as kimberlite pipes, named after a location in South Africa. These pipes are corridors of an utterly unique type of rock that cooled from a molten state, and which originated far down in the Earth's mantle. Some researchers have estimated the depth of origin of the kimberlite mantle as being near 150 miles below the Earth's surface, or dozens of miles below even the deepest portions of the Earth's crust. Yet some diamonds, which are a form of pure carbon, have small inclusions of garnet in them.
How did the garnets get there? What is going on? The geochemistry is complex, but the short version is that these garnets could only have originated from shallower crust that was pulled down deep into the Earth's mantle and incorporated into the mantle material that erupted through the kimberlite pipe.
If large quantities of hydrocarbons were originating within the deep Earth, as the "abiotic" oil theories suggest, then let me ask the next question: Is there any significant amount of oil and gas associated with places where the surface of the Earth is closely connected with the Earth's deep interior?
There are no oil seeps in Hawaii, nor in Yellowstone Park, for example. In both of these very fascinating places (and there are many more on the face of this Earth) there is what is called a "mantle plume" or a hot spot straight down beneath your feet. That is, the "hot spot" is an essentially vertical corridor in the crust of the Earth.
Through this corridor, rock is being heated to a molten state and pushed toward the surface, directly up from the Earth's mantle or at least from the base of the crust. In other words, in places like Hawaii and Yellowstone, you have a very "shallow" connection between the surface of the Earth and its hot, molten interior.
In Hawaii, you have the great basalt volcanoes, particularly what we see today on the Big Island of Hawaii. These volcanic vents on Hawaii are connected directly to the deep Earth, from which comes the heat energy that melts the rock into molten lava that you have probably seen in videos, if not in person. (And believe me, it is very impressive if you are up close and personal.)
As you move to the northwest from the Big Island, the other islands of the Hawaiian chain are older, have eroded down over millions of years, and have settled downward into the Pacific tectonic plate. Still, these islands too are remnants of volcanism that originated in the deep Earth above the hot spot. So where is the oil and gas? The answer is that there is none. All you see in Hawaii is a heck of a lot of magnesium-iron basalt, with very minor amounts of carbon dioxide and trace amounts of methane being detected in occasional lava flows.
In another example, Yellowstone Park sits atop an immense volcanic caldera, meaning a volcanic crater of immense size. The Yellowstone caldera is about 40 miles by 50 miles in surface dimension, more or less. And out of this caldera has poured, over many millions of years, many massive series of volcanic flows.
Technically, the earliest flows are called basalt, similar to the rock type that we find in Hawaii. Later flows were a rock type called andesite, named after the kind of rock that is common in the great Andes Mountain chain of South America. (This phenomenon is closely related to what is called "seafloor subduction.")
And the most recent volcanic flows at Yellowstone were a rock type called rhyolite, which is chemically equivalent to granite, except that granite is what you get if the rock cools and crystallizes at depth. That is, in a few million more years, the subterranean source of this molten material at Yellowstone might cool to become what we call granite. Then again, Yellowstone could also erupt upward in one of the largest volcanic explosions in geologic history. We will just have to wait and see.
But what we do not find in Yellowstone is oil or gas. Despite the connection to a "hot spot" in the Earth's crust, there is nothing that even remotely could be called an oil or gas deposit. And the best science is that whatever is down under the ground at Yellowstone will never become oil or gas.
A reader named Thomas, from New Mexico, e-mailed as follows:
"I have seen Web sites that discuss 'super wells' in Russia. The Russians drilled many miles into the Earth, and found large quantities of oil and gas. Isn't this evidence of oil forming deep in the Earth?"
If you follow the lead of Thomas and perform a Web search for "super wells" or try the term "Peak Oil scam," one of the sites you will find refers to a number of Soviet and, later, Russian wells that were supposedly drilled to depths of 40,000 feet and more. If the Russian drill bits penetrated this far, it was first and foremost a truly remarkable technical achievement.
That depth approaches the bottom of the Earth's crust in parts of Russia, and may even get into the upper mantle. What did the Russians find? Good question. The Web sites claim that these are some sort of Russian "super wells" that produce immense quantities of oil. Supposedly, this is why Russia is one of the leading oil producers in the world today, rivaling Saudi Arabia in total daily oil output.
In all candor, we in the West know surprisingly little about these deep Soviet and Russian wells. During the Cold War, the Soviets diverted a significant amount of resources to drilling a number of very deep wells. The details of these drilling projects were considered a state secret, although there was good evidence that the Soviets were attempting to do exactly what one might think. That is, they wanted to discover what were the types of rocks in the stratigraphic column beneath the drill rigs. This kind of stratigraphic information would normally be useful for both geological research and further geophysical prospecting.
There was a school of geological thought in the Soviet Union that did buy into the "abiotic" theory of the origins of oil. This was, in no small measure, because one of the originators of the "abiotic" oil theory was the great Russian chemist Dimitri Mendeleev.
There were rumors in the geological community, as well as in the Western community of defense analysts, that if the Soviet deep wells encountered any significant hydrocarbon resources, they would use nuclear explosions to shatter the rocks and increase the flow of any oil or gas to the well bore.
Did the Soviets ever find oil, let alone nuke a well? Not that we are aware.
Even in the post-Soviet era, the contemporary Russians are taciturn about the purpose, let alone the output, of their known deep wells. One thing that we know for certain is that there are no massive pipeline systems around these wells.
Pipelines would ordinarily be necessary to move any large amounts of oil away from the hole in the ground.
Another thing that we know is that most former Soviet, and current Russian, oil production has come from giant oil fields such as Samotlor and Romashkino. These are conventional oil fields, with well-understood geological control over the oil, such as identifiable source rocks, host rock formations, and structures and other traps that contain and confine the oil in places where it can be accessed by drilling. The origins of these identified oil fields have nothing to do with deep Earth, "abiotic" genesis.
And looking forward, through a process called "Hubbert linearization," which I have discussed in other Whiskey articles, it is apparent that Russia is about to enter its own version of Peak Oil. That is, based upon the production trends from its known oil fields, Russian oil production is on the verge of a significant, irreversible decline. Some analysts are predicting a rather precipitate collapse in Russian oil production over the next 10 years.
A young student named Amelia from the Philippines sent an interesting e-mail that touched on these types of arguments as well. Amelia said:
"Just offshore Vietnam is a big oil field in the South China Sea. The field is producing large amounts of oil from Precambrian rocks, more than 1 billion years old. If, as you have said in your articles, oil is of more recent origin than the Precambrian Era, how do you explain this? Hasn't the oil been in these Precambrian rocks for a long time? Or could the oil be coming up into the Precambrian formations from deeper sources?"
This is a great point from Amelia. Her question embodies much of the argument of the deep Earth hydrocarbon side of the "abiotic" oil debate. If there is oil and gas of deep Earth origin, it must be migrating upward into the crust, where it is trapped by other geological controls. And it may have been doing so for a period of time that could reach back into the Precambrian Era. So what about this Vietnamese oil field in the Precambrian rocks?
To reach the best understanding, we will have to discuss some geology. The region to which Amelia refers, offshore southern Vietnam, lies beneath the relatively shallow, and utterly beautiful, turquoise-blue waters of the South China Sea. Despite the present flat appearance, this area has a very complicated and truly complex geological history. The rock sequence in this area has at its basement Precambrian rocks that are, as Amelia mentioned, more than 1 billion years old. (Technically, they are called granulites and gneisses.)
Geologists who have studied the area believe that during the Paleozoic Era (Cambrian through Permian periods, about 550 million to 250 million years before present), this chunk of the planet was part of an ancient, exposed continental landmass. It would be similar to what we see today in northern Canada or northeast Brazil, where vast expanses of Precambrian Shield are exposed at the surface.
During this period of time, the exposed Precambrian surface was heavily weathered, and eroded down by the elements of that time. There are few, if any, sediments of any time frame of the Paleozoic Era on top of the Precambrian basement rock that is offshore Vietnam.
The rock record suggests that the region that is now offshore Vietnam began to submerge during the Jurassic Period (about 210 to 160 million years ago), due to subsidence of the Earth's crust. Thus did this region begin to accumulate deposits of sedimentary rocks.
This subsidence and deposition of sediments continued until about 65 million years ago. So the rock record is that this area had about 150 million years of geological history during which to accumulate sediments, which formed into a wide variety of different kinds of rock formations.
As these sediments were accumulating so many millions of years ago, in what would become the area offshore Vietnam, to the north, there was an episode of what is called "mountain building." That is, from southern China to southwest Borneo, an ancient mountain range was being pushed upward by forces associated with plate tectonics.
These rising mountains were the source for much of the sediment that poured into the area in which we are now interested. This mountain chain was similar to what we see today in the Andes, for example.
During all of this geological history, the Precambrian rocks, and the much younger sediments above the Precambrian basement, were intruded by deep magmas that were working their way up from the bottom of the Earth's crust, if not the upper mantle. At the surface of the Earth, one would have seen extensive volcanism, again of the type associated with what we see today in the Andes Mountains.
After a very long and complicated sequence of geological events, the volcanism halted about 60 million years ago. The area began to submerge again, as the crust of the Earth subsided, resulting in more sediment deposition up to the present day.
There is absolutely solid evidence that the rocks in which the Vietnamese hydrocarbons formed were rich in algae and were, in fact, the equivalent of an oxygen-poor lake environment. As the algae-rich sediments were buried and subsided over time (Oligocene to Miocene epochs, about 35 to 10 million years ago), the organic matter in the rocks began to transform into what we see today as oil and gas. Later in the sequence, the sediments that were laid down in late Miocene time created a very tight shale "cap" on top of the entire rock body, sealing the hydrocarbons beneath.
So here is what we have today. There are relatively young Miocene-age (20 to 10 million years) sedimentary rocks lying above folded sedimentary rocks of Jurassic age. These Jurassic sediments were intruded by later magmas (technically, called granitoids). And all of it lies atop fractured basement rocks of Precambrian age.
Complicating the geology of the area, the rocks beneath the waters offshore Vietnam are crossed and broken by numerous faults, or relative Earth movements. These faults and fault systems are among the most complex one will find in any oil province in the world. Over long periods of time, the faults have opened and closed, and moved one way and then the other.
This relative movement has occurred several times during various tectonic episodes. That is, the faults have been compressed and then extended. They have compacted due to differential loading of sediments above them, and then decompacted due to erosion of the sediments. It takes a lot of very good geology and geophysics just to begin to understand what is going on. And then you have to drill for oil and find it. It ain't easy. And it is not for amateurs.
The petroleum in the offshore area of Vietnam is thus of Oligocene and Miocene age, and it originated in very much biological fashion. One can actually trace the oil from its current reservoirs, back to the source rocks that are located only a few dozen miles away at most. As things happened, the oil migrated from the Miocene rocks where it originated, and is now filling the available fractures and pores in, among other rock formations, the Precambrian basement.
So Amelia correctly noted that the waters offshore Vietnam are producing oil from Precambrian rocks. But what Amelia did not understand is that the oil originated relatively recently in geological history and migrated into the far older Precambrian rocks, as well as into rocks of Jurassic age.
Today, there are seven significant oil fields located offshore Vietnam, with estimated reserves of almost 2 billion barrels of oil. Much of the oil that is being lifted from these fields comes from granite-like Precambrian rocks. But the oil is not "abiotic," and it did not form in Precambrian time. The best science is that the hydrocarbons from the Vietnamese waters originated in the algae-rich, oxygen-poor lake beds of Miocene time.
The algae-rich, oxygen-poor lake beds of Miocene time in the part of the world that is now offshore Vietnam were quite similar to the environment in which the so-called "oil shales" of Utah and western Colorado originated.
The big difference is that the oil offshore Vietnam has had more of what is called a "thermal history." That is, the organic material has been, in essence, buried, heated and "refined" within the crust of the Earth such that it has become a valuable grade of petroleum -- whereas the oil shales of the U.S. West are still rather "undercooked."
Chemically, the "oil" in the shales of the American West should be called "kerogen." This is a type of substance that could have used a few million more years of burial, subsidence and thermal history. Had this occurred, the kerogen would probably have been upgraded to a lighter, more valuable, and easier-to-produce form of oil through the input of what I call the "tectonic energy" within the Earth.
The United States is certain to develop and utilize its kerogen resources one of these years. My colleague Dan Denning has reported extensively on a project in western Colorado that is being sponsored by Shell Oil Co., and using some very innovative technology to produce kerogen and upgrade the product to a type of fuel oil.
But even in the best of circumstances, the United States is just plain decades behind where we, as a nation, need to be. America will not see more than a few thousand token barrels per day of "oil from shale" for many more years.
Meanwhile, the Earth's reserves of conventional oil are depleting. And a new global struggle is already in progress, in which the nations of the world are scrambling to secure energy resources for the 21st century.
With this in mind, the time for the United States to be making the required investment in "oil shale" development is now, today, immediately, with a "what-are-we-waiting-for" sense of urgency. America should be approaching the issue of its future energy needs with the intensity of the Manhattan Project of the Second World War, or if that is too harsh a comparison for you, then with the same full-bore level of effort that went into Project Apollo of the 1960s.