Scientists use microbes to extend life of oilfields

Scientists from the UK and Canada have begun field trials to find out whether microorganisms hold the key to unlocking vast amounts of energy trapped in the world’s unrecoverable heavy oil

It is estimated that six trillion barrels of oil remain underground as a result of the oil solidifying or becoming too thick to be economically extracted using conventional methods.

The field trials consist of pumping a mixture of nutrients, dissolved in water, down an oil well above exhausted oil deposits in Western Canada. If the scientists have got their sums right,
natural gas will flow back out, with the microbes multiplying as they feast on the nutrients and digesting the tar-like oil at a dramatically increased rate.

The research team is headed by Professor Ian Head and Dr Martin Jones of Newcastle University and Professor Steve Larter, who works at both Newcastle University and the University of Calgary.
Together they are responsible for discovering how microorganisms break down oil deep underground. The team announced their findings in a ground-breaking paper, which was recently published in
the internationally acclaimed academic journal, Nature.

The work answers a question that has long puzzled geologists, by showing that two types of naturally-occurring microorganisms found in oil-rich environments were responsible for turning
deposits into methane. The first microbe is a bacteria called Syntrophus, which digests the oil to produce hydrogen gas and acetic acid. The second microbe is called Methanogens, which produces
methane by combining the hydrogen with carbon dioxide.

The researchers also found that the geological timescale of this process could be shortened tens of millions of years to a few hundred days in the laboratory by providing the microorganisms
with special nutrients. They believe that similar results could be achieved in an oilfield in a timescale ranging from one year to several decades.

‘The research we published was important scientifically because it settled an argument that has been running for decades about how oil is degraded in oilfields; it turns out it is converted to
natural gas,’ said Professor Head, who is an environmental biologist based at the Institute for Research on Environment and Sustainability at Newcastle University.

‘The discovery of how this process works could have major implications for the oil and gas industry because we think we will be able to extend the 20-30 year operating lifespan of a typical oil
reservoir,’ he added.

In response to the environmental concerns, the universities say that the technology they have developed will be less environmentally damaging than some other technologies which oil companies
have attempted to use to extract heavy oil reserves and that burning methane is environmentally preferable to burning oil. Furthermore, the technology could also be used to provide a clean
source for producing hydrogen gas.

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