Biotechnology offers novel approach to halt pipeline corrosion

The common oilfield problem of microbiologically influenced corrosion (MIC) is getting an uncommon treatment from Australian biotechnology provider Biosignal. The company is touting a concept known as biomimicry as an alternative to biocides for bacterial control.

Bacterial growth on the inside walls of pipelines and processing systems is a common problem in many oil fields around the world. This growth comes from microbes that naturally occur in oil and gas systems. These microbes adhere to the pipe wall, eventually forming a bacterial biofilm or sludge that becomes a breeding ground for more bacteria. During their metabolic cycle, the bacteria produce very corrosive byproducts, causing the well-known and aggressive process of MIC.

Common treatment scenarios for preventing MIC include pumping biocides such as THPS and glutaraldehyde into the production stream, thus killing the bacteria and preventing the formation of a corrosive film.

However, these biocides are not without their challenges, as Rohan McDougall, chief operating officer of Biosignal, recently explained. “Traditional biocides have low activity against certain biofilms, and prolonged biocidal treatment may encourage bacterial resistance.”

In addition, biocides pose exposure and transportation concerns for oilfield operators, as well as environmental discharge concerns for regulatory agencies in many parts of the world.

Biosignal’s goal was to find a biological alternative to conventional biocides that would sidestep these challenges. According to McDougall, the company employed biomimicry, which uses natural models as the basis to overcome biotechnology hurdles. In this case, the company found a marine organism that produces chemicals that prevent biofilm formation on a pipe wall.

Biosignal discovered this marine organism on a type of seaweed, which used the chemicals to prevent bacterial surface colonization on its leaves. “This is a naturally occurring process, and it has been effective for millions of years without causing bacterial resistance,” McDougall said.

“In our approach, compounds based on those found in the seaweed interrupt the signaling systems that bacteria use to link up, colonize the surface, and form and maintain biofilms,” McDougall continued. “So, instead of killing the bacteria, our technology blocks the signaling to stop colonization.”

Oilfield antibacterial testing under way in Scotland

Biosignal has begun conducting a series of laboratory evaluations designed to shore up the promised benefits of its biotechnology. In May 2007, the company reported that testing conducted at Monash University in Melbourne, Australia showed that the compounds remove biofilms formed from Desulfovibrio desulfuricans (a major problem organism for the oil field) more effectively than THPS and glutaraldehyde. In one test, Biosignal’s active agents outperformed THPS by a factor of 1000 in reducing an existing biofilm.

In a separate series of tests, Biosignal’s compounds were tested in combination with existing biocides that are commonly used by oil and gas producers. In these tests, the Biosignal compounds reduced the biocide dosage by at least 50% to achieve the same biofilm reduction result.

In August of this year, Biosignal announced that it had commissioned Aberdeen-based Commercial Microbiology to assess and develop the lead compounds responsible for reducing microbial contamination in oilfield pipelines and equipment. The work, which is partially funded by Santos and BHP Billiton and is scheduled to be completed by the end of the year, will test the ability of Biosignal’s compounds to remove biofilms formed in a seawater environment.

“Assuming a successful outcome with these tests, we will proceed to full-scale trials in 2008,” McDougall said. “We have already received several offers of assistance from various industry players to establish and operate these field trials.”

To learn more about Biosignal and its biomimicry technology for the oil field, visit www.biosignal.com.au or contact Rohan McDougall by email.

Ted Moon is the Technical Editor of JPT Online. He brings information on emerging technologies, R&D successes, new field applications, updates from SPE papers about recent innovations, and more. If you have a question or suggestion for future article topics, email Ted at teched@spe.org.