Self-Healing Pipelines

Fixing leaking pipelines can be tricky and expensive. But now engineers at a company in Aberdeen, Scotland, have developed a novel way to get the job done. It involves using artificial platelets inspired by the way our blood clots when we get cut.

The platelets, actually small pieces of polymeric or elastomeric material, are introduced into the pipeline upstream and use the flow of the fluid to carry them down the pipe toward the leak. There the pressure forcing the fluid out of the leak causes the platelets to amass at the point of rupture, clogging up the escaping fluid in the process, says Klaire Evans, sales and marketing engineer with Brinker Technology, which is developing the technology.

The method has been tested on a handful of pipelines owned by BP and Shell. According to Sandy Meldrum, an engineer with BP, in Aberdeen, the technology was used to fix a leak in an undersea water injection pipe at an oil field near the Scottish Shetland Isles. Normally this kind of leak would have to be fixed using remotely operated vehicles, whose operators would place a clamp over the leak. But by using Brinker’s technology, BP saved about $3 million, says Meldrum.

The idea for the platelets originally came from Ian McEwan, an engineer at the University of Aberdeen and director and founder of Brinker, when he was sitting on a train and accidentally cut his finger. He wondered whether the ability of the human body to seal cuts could be applied to pipelines.

Leaks are an ongoing problem for the oil industry, says Ray Burke, a projects engineer with Shell, also in Aberdeen. There are many methods of plugging the leaks in steel pipes, he says, depending on whether the pipe is on land or under the sea. Many of the methods involve having to shut down sections of pipeline. But all methods are expensive, running to at least $200,000 a day.

McEwan’s solution runs to a fraction of this cost and can be tailored for the specific conditions of the leak. Typically, the platelets vary in size from 0.3 to 50 millimeters, with shapes ranging from discs to cubes. Similarly, hardness has to be tailored to each situation: use too soft a material, and the platelets will deform under the pressure and be squished through the hole; use too hard a material, and they will fail to stem the flow through the leak. What is crucial is that the platelets are neutrally buoyant so that the fluid can carry them, says Evans.

The precise amount of platelets will also vary, with only a proportion of them actually forming a “scab” on the leak. Also, the buoyancy can be tailored to increase the chances of the platelets reaching the hole more efficiently. For example, if it is known that the leak is on the underside of the pipe, then using a slightly denser material that stays in the lower section of the pipe would be more beneficial.

Brinker has also been experimenting with ways to use the platelets not just to plug leaks but also to help locate them. “When you have pipes hundreds of kilometers long, just knowing they are leaking is a challenge in the first place,” says Burke. So far Brinker has tried using RFID tags with the platelets and even coating them with a harmless radioisotope.

The company is now seeking approval to start using its technology for water pipes. In England and Wales alone, 3,600 million liters of water is lost every day through leaks in the infrastructure, costing water companies billions of dollars in repairs and causing drivers untold disruption in the form of dug-up roads.