Oct 7, 2010 14:47 GMT  ·  By

Scientists have recently determined that the bacteria which can regularly be found around oil drilling sites can be analyzed in such a manner that they provide a host of useful information about the state of the oil field as a whole.

This idea belongs to a new doctoral thesis on the topic, which was defended at the Delft University of Technology (TU Delft), in the Netherlands, on Tuesday, October 5.

In the end, applying this process to an oil field could increase its efficiency considerably, thus justifying the initial expenses. The approach is called “biomonitoring.”

The new work makes sense as soon as you began thinking about oil deposits as if they were small self-sufficient, closed ecosystems, with their specific bacterial populations.

Microorganisms living here are adapted to carrying out their basic processes in temperatures and pressure levels that would kill other bacteria or microbes.

But oftentimes oil companies disrupt this habitat, by introducing seawater, for example. This is done so that the oil becomes more readily accessible. However, there are other side-effects to doing this too.

One of them is the introduction of the chemical sulphate in an environment that previously had none. This leads to a spur in development for microorganisms that thrive on this substance.

As new species encroach in the oil deposits' natural ecosystems, the ratio and type of bacteria that are available after sampling changes. One of the most common tell-tale signs is the production of the chemical hydrogen sulphide.

This element, while not toxic in itself, reduces the quality of the oil in the deposit, and also attacks the surface of the pipes that carry the crude around the processing plant.

But TU Delft PhD student Geert van der Kraan says that the oil industry might be better off if it would keep an eye out not just for hydrogen sulphide levels, but also for other types of bacteria in the deposit.

One of the immediate practical applications for this could be that no hydrogen sulphide will be produced early on in the extraction process.

“There are very positive indications that biomonitoring is a realistic option,” the expert said.

“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. This may well enable the oil field to be exploited more efficiently,” he added.

“Encouraging the growth of certain groups of bacteria at specific locations in the oil field is an interesting proposition,” van der Kraan added.

“This growth 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,” he concluded.