Austria is seldom seen as an oil producer, but in the fertile corn fields northeast of Vienna there are wells that might have been abandoned as uneconomic 5 years ago but today are still producing.
Some produce at a rate that takes them into the stripper category, but Austria does produce around 5 million bbl/year from fields that started production in 1938.
Bugs and spills
The reason that the fields can remain in economic production is attributable to bacteria and research into oil spill clean-up at Norway's University of Bergen. In the late 1970s, Egil Sunde became the first person to study the effects of bacteria on oil spills at the university. He found that bacteria could clean up oil from beaches, not so much from eating the oil-although some 20% of bacteria do so-but by producing enzymes from their digestive processes that act as surfactants to wash the oil away.
Later, when working for Statoil ASA, where he now works in their research center, these same bacteria became his enemy, because in oil fields they can produce hydrogen sulfide, which causes corrosion problems in water injection systems. He worked for several years as part of a team working on drilling muds that could combat the effects of certain bacteria.
However, he managed to persuade his Statoil colleagues that among the billions of harmful bacteria there were also millions of "good guys" which, when provided with the right conditions, would flourish and create a surfactant.
He said, "The bacteria that flourish most are also the best at creating a surfactant. Oil is washed from the pore walls and comes flowing out."
Statoil took out a patent on his ideas, and he is now advising colleagues at OMV GMBH in Vienna.
Improving production
Reinhardt Bacher, an OMV senior petroleum engineer, has found that by providing the right conditions and introducing the right type of bacteria, production can be improved.
He said, "The new bacterial approach represents a scientific and mysterious way of getting more oil out of the wells. We weren't risking anything. Some of the wells had a water cut of 98%, and our oil recovery factor was about 60%. The trend is good, with oil production now stabilizing. We know it works but not quite why it works."
Now Statoil will use the method on its Norne oil field development in the Norwegian Sea. Results from a pilot project suggest that about 30 million bbl of incremental oil could be recovered from this field over 15 years.
Statoil and the University of Ber- gen are developing new types of bacteria, and a fertilizer plant is being built on the Norne floating production, storage, and offloading vessel to grow the bacteria needed.
But what is intriguing about the development is that in an industry where problems are solved by well-thought and proven engineering, no one really knows why the process works.
Statoil's project manager for microbial improved oil recovery at Statoil's technology division said, "We haven't quite fully understood what happens in the reservoir."
