The growth of microbes within bioflms contributes to serious issues in oilfield systems, including reservoir souring and corrosion. Current methods of biofilm control within the oil and gas industry include physical removal and treatment with chemical biocides.
Although these methods can be effective, incomplete biofilm removal, or poor diffusion of chemical into the biofilm can allow regrowth to occur once treatment has stopped. Consequently a new, more effective approach to controlling biofilms could make a significant contribution to reducing damage caused by microbially influenced corrosion.
Bacteriophages are viruses that infect bacteria, and it has been demonstrated within other industries that they have the ability to degrade the exopolysaccharide that is a key constituent of biofilms, and plays an important role in protecting the cells within a biofilm from chemical treatments. For example, work has been undertaken to investigate the potential of bacteriophages as a means of tackling biofilm growth on medical devices, and the success of bacteriophages in degrading biofilm polysaccharides and infecting cells has also been demonstrated with bacteria isolated from a food processing factory. If similar performance could be demonstrated using oil and gas industry samples, bacteriophages may have potential as a more effective and targeted means of biofilm treatment than currently deployed methods.
There may also be additional benefits associated with reduced use of chemical biocides. NCIMB’s project, which has received funding from Innovate UK, aims to isolate and identify bacteriophages that are selective to biofilmcausing organisms in North Sea reservoirs. We are using high throughput sequencing to study microbial populations in reservoir samples supplied by a North Sea operating company, and provide information on the relative abundance of genera of interest.
The efficacy of the isolated bacteriophages will then be tested against pure and mixed-culture microbial enrichments from the same samples before testing the bacteriophage against static biofilms on corrosion coupons and studs. Results will be compared with those obtained with current chemical biocides.