Oil’s origins revisited

Robert Matthews

• Last Updated: December 22. 2008 9:30AM UAE / December 22. 2008 5:30AM GMT

Once upon a time, clever people scared themselves by trying to predict the end of the world. Sir Isaac Newton’s best estimate, for example – recently uncovered in archived manuscripts – was some time in the year 2060.

Today smart people seem intent on scaring all of us by trying to predict an event no less apocalyptic for modern economies: the arrival of “peak oil”, after which output of crude oil falls into terminal decline.

Last week it was the turn of Fatih Birol, chief economist to the International Energy Agency (IEA), who argued that conventional crude output could plateau in 2020. How seriously we should take this is anyone’s guess. Only last month, the IEA itself was claiming the turning point would be 2030 – 10 years later than its current estimate. With Opec having just imposed its largest-ever cut in oil production, the IEA may well have to issue another estimate next month.

Like predictions of the Final Trump, attempts to guess when oil will run out have a long and sorry history. In 1874, the chief geologist of Pennsylvania, then America’s leading oil-producing state, estimated the nation only had enough of the stuff to last around four years. Nowadays, there seem to be almost as many views as experts, with some claiming peak oil may have been passed some years ago and others – as this newspaper reported recently – insisting it lies far in the future.

In the end, all the arguments centre on simple supply and demand: is there enough exploitable oil in the ground to meet projected needs? So far the ingenuity of petroleum engineers has kept the black gold flowing through advances in the technology of finding and extracting oil. But it seems obvious that it must run out eventually; after all, there’s no more of the stuff being made deep underground. Or is there?

According to the textbooks, oil is the product of 150 to 200 million- year-old fossilised remains of marine organisms being transformed by the combined effect of bacterial action, heat and pressure. But according to some scientists, there may be other sources of oil, created by different means, which remain undiscovered simply because no one expects to find them.

During the 1950s, a team led by the Soviet geologist Dr Nikolai Kudryavtsev of the All-Union Geological Research Institute pointed out that crude oil is sometimes found at sites with no obvious connection to fossilised organisms – such as the Siljan Ring structure of central Sweden, where tar and oil seep out of pure crystalline granite.

According to Dr Kudryavtsev and his colleagues, these puzzling discoveries suggest that oil can also be formed in the absence of living organisms – for example, from hydrocarbons trapped inside the Earth during its formation around 4.5 billion years ago.

Such an “abiotic” – life-independent – origin raises the possibility of vast new reserves of oil in places so far ignored by geologists. Despite this, for many years few outside the Soviet Union took the abiotic theory seriously. Sceptics pointed out that crude oil contains chemicals associated with living organisms – apparent proof-positive of its biological origins.

But not everyone was so sure. In the early 1980s, an iconoclastic astrophysicist named Thomas Gold of Cornell University, New York, revived the abiotic theory with a more detailed explanation – and a way of testing it. He suggested that oil has its origins in primordial hydrocarbons trapped within the Earth at depths of 250-300km, which are turned to crude oil by the action of the huge pressure and temperature.

According to Gold, the apparent link with living organisms comes from the hydrocarbons seeping upwards and passing through what he called the “Deep Hot Biosphere”, packed with bacteria and extending from depths of around 10km to the surface. It is these bacteria, he claimed, which leave the trace chemicals suggesting a link with living organisms.

Gold went further, however, persuading the Swedish State Power Board to test his theory by drilling for oil in Sweden’s Siljan Ring. The aim was not just to find oil, but to find “extremophile” bacteria able to survive incredible temperatures and pressure.

Between 1986 and 1990, engineers drilled down into the granite to a depth of almost 7km. And according to Gold, the results confirmed his theory, with engineers extracting around 90 barrels of crude oil plus extremophile bacteria – and all from very unpromising granite.

Unfortunately for Gold, the engineers ran into technical difficulties, and drilling had to stop. He then found that the evidence he had accumulated was too meagre to convince sceptics – who insisted the oil could be explained by standard chemistry, and the bacteria were the product of contamination.

When Gold died in 2004, his challenge to the textbook account of the origin of oil appeared to die with him. Yet research into both the state of the early solar system and bacteria suggests it cannot be completely dismissed.

There is now compelling evidence for the presence of hydrocarbons on both meteorites and comets that bombarded the primordial Earth. Meanwhile, scientists continue to find bacteria able to survive in extraordinary conditions, among them Nanoarchaeum equitans found in undersea hydrothermal vents, which thrives at pressures of over 10 atmospheres and temperatures of around 100 C.

Critics of Gold’s claims concede that there may be reserves of abiotic oil awaiting discovery. The question is where and how much? Most insist that it will be too small to have any impact on the debate over “peak oil”.

Yet the truth is no one knows for sure – and it may take the impending arrival of peak oil before we do.



Robert Matthews is Visiting Reader in Science at Aston University, Birmingham, England