Bacteria Monitors Can Measure State of Oil Fields

(U.S. Department of Energy)

A doctoral dissertation published at the Delft University of Technology in the Netherlands suggests that monitoring bacteria levels in an oil field can provide useful indicators on the state of that oil field. Geert van der Kraan, who conducted the research, received his doctorate degree this week.

For his dissertation research, van der Kraan investigated whether microbial changes (i.e. the types and quantity of bacteria present) could be used as an information source to track what is taking place in an oil field, a concept known as biomonitoring. It is an approach, van der Kraan says in a press release, that with smart management can boost oil exploitation or prevent production of harmful hydrogen sulphide accumulations at an early stage.

In order to obtain more oil from a field, companies use methods such as pumping sea water into the field to flush through the oil. This injection of sea water introduces sulphate, which changes the composition of the bacteria populations in the oil field. Bacteria that reduce sulphate thrive, prompting the release of hydrogen sulphide, which is not only toxic but also has an adverse effect on the quality of the oil and damages the pipelines.

Thus, says van der Kraan, these bacteria have always been closely monitored by the oil industry, but closer biomonitoring may tell oil field operators even more. “The changes in the microbial diversity of the pore water from the oil well can provide a good understanding of the changing geochemical conditions in the oil field itself,” van der Kraan says. “This may well enable the oil field to be exploited more efficiently.”

Bacteria can also be used to improve oil extraction. The growth of certain groups of bacteria at specific locations in the oil field, he contends, “partially blocks the porous structure of the rock that contains the oil, forcing the water to take another route. It can then move oil that is more difficult to reach, increasing the effectiveness of oil extraction.”

The Integrated System Approach Petroleum Production program, a collaboration between the university, Shell International Exploration and Production, and the Dutch research institute TNO, supported van der Kraan’s research.

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