Researchers from MiT have discovered a coating that could help prevent blockages in oil drilling pipes, potentially protecting the environment from oil leaks, as well as saving millions of dollars in lost oil.
The team was inspired by the events that led to the Deepwater Horizon oil spill in the Gulf of Mexico. Following a deadly explosion and blow out in April 2010, BP engineers were confident that they would be able to stop the flow by placing a 125-ton dome over the broken wellhead.
However, the recovery operation failed because of a blockage caused by ‘an icy mixture of frozen water and methane, called a methane clathrate’. As the MiT website reports, “Because of the low temperatures and high pressure near the seafloor, the slushy mix [of methane clathrate] built up inside the containment dome and blocked the outlet pipe, preventing it from redirecting the flow. If it hadn’t been for that methane clathrate, the containment might have worked, and four months of unabated leakage and widespread ecological devastation might have been prevented.”
Publishing the results of tests on their new coating in the journal Applied Materials & Interfaces, the research team outlined that problem, stating, “Clathrate hydrates are icelike solid substances that can form inside oil and gas pipelines and are responsible for flow blockages, sometimes leading to catastrophic failures. Minimizing hydrate formation and adhesion on pipeline surfaces can effectively address this problem.”
The solution they devised is a new coating, whose design was based upon earlier research from 2011. As the online scientific journal Phys.org reported at the time, “The study produced several significant results: First, by using a simple coating, [the researchers] were able to reduce hydrate adhesion in the pipe to one-quarter of the amount on untreated surfaces. Second, the test system they devised provides a simple and inexpensive way of searching for even more effective inhibitors. Finally, the researchers also found a strong correlation between the ‘hydrate-phobic’ properties of a surface and its wettability — a measure of how well liquid spreads on the surface.”
The report continued by noting that, “The basic findings also apply to other adhesive solids, — for example, solder adhering to a circuit board, or calcite deposits inside plumbing lines — so the same testing methods could be used to screen coatings for a wide variety of commercial and industrial processes.”
Famously, one of these was a non-stick coating for shampoo, mayonnaise, or similar containers. As the industry journal Packaging Gateway reported, “Researchers at the Massachusetts Institute of Technology (MIT) have developed a non-sticking coating for food packaging, which will allow substances such as ketchup to pour from containers easier.”
Converting this idea to the challenging environment of oil extraction has not been simple, but the new pipeline coating is not dissimilar to that used in ketchup bottles. As Kripa Varanasi, professor of mechanical engineering and one of the research team members explains, in this case, “we are using the liquid that’s in the environment itself rather than applying a lubricant to the surface. The key characteristic in clathrate formation is the presence of water, so as long as the water can be kept away from the pipe wall, clathrate buildup can be stopped. And the liquid hydrocarbons present in the petroleum, as long as they cling to the wall thanks to a chemical affinity of the surface coating, can effectively keep that water away. If the oil [in the pipeline] is made to spread more readily on the surface, then it forms a barrier film between the water and the wall.”
You can watch the MiT produced video explanation of the coating discovery on this YouTube link here.
Given the extreme temperatures and pressures involved in deep water drilling, it is difficult to reproduce the exact conditions experienced at a wellhead, but lab tests conducted have shown that the coating was able to keep pipes clear of a proxy chemical [used in place of actual methane clathrate] very effectively. As Varanasi said, “We didn’t see any hydrates adhering to the substrates.”
This is a ground-breaking development for the oil drilling and oil pipeline lubricant industry. Current prevention measures, known as flow assurance measures, have existed for a long time, but as Varanasi explains, “they are expensive or environmentally unfriendly.” Current use is estimated as costing the industry “hundreds of millions of dollars” every year. But they are essential, as they prevent hydrate build up that can cause blockages that lower flow rate, or cause accidents that can cost billions. As Varanasi states, “Clogging can lead to catastrophic failures.” Adding that, “Hydrates are a major problem for the industry, for both safety and reliability.”
The challenge could become even greater, says Arindam Das, the paper’s lead author, because methane hydrates themselves, which are abundant in numerous locations such as continental shelves, are a potential fuel source. The impact of capturing and processing methane hydrates as a power source could be huge, if an economic method of extraction could be developed. “The reserves themselves substantially overshadow all known reserves [of oil and natural gas] on land and in deep water,” he says.
But as the MiT website notes, “Such deposits would be even more vulnerable to freezing and plug formation than existing oil and gas wells. Preventing these icy buildups depends critically on stopping the very first particles of clathrate from adhering to the pipe.
“Once they attach, they attract other particles” of clathrate, and the buildup takes off rapidly, said research co-worker Taylor Farnham. “We wanted to see how we could minimize the initial adhesion on the pipe walls.”
While this discovery does bring the possibility of tapping methane hydrates as a resource a little closer, for now the team’s goal is to promote their discovery as a solution to a current problem in the petroleum industry.
In fact, the breakthrough coating is already gathering significant attention from both drilling experts and coating manufacturers. An oil pipeline coating that prevents clogging will save money on a daily basis by replacing current methods and lowering maintenance costs is a popular coating product.
The Deepwater Horizon tragedy will be remembered for years to come, with the oil extraction industry still reeling from its effects. But if this new product is able to prevent just one similar incident then the coating will be more than worth its weight in gold, or even black gold.
