Penn State University researchers have nanoengineered a flexible, crack-resistant cement that can seal leaky gas wells. “That’s important because there are millions of orphaned and abandoned wells around the world, and cracks in the casings can allow methane to escape into the environment,” says Arash Dahi Taleghani, associate professor of petroleum engineering.
Leaky gas wells are not only a waste of natural resources, but a significant player when it comes to climate change via the release of methane into the atmosphere. Engineers at Penn State University have developed a new type of flexible cement they say can help contain the problem, by being fed into the very fine gaps around deteriorating wells that traditional cements are unable to fill.
While major gas leaks are generally tended to promptly, smaller ones can go unnoticed for some time, even years. With these wells sometimes stretching for miles underground, shifts in temperature and pressure can cause cracks in the cement originally used to secure the pipes and contain the gas, enabling it to filter through into waterways or out into the atmosphere. Repairing the damage can be tricky business.
“In construction, you may just mix cement and pour it, but to seal these wells you are cementing an area that has the thickness of less than a millimeter, or that of a piece of tape,” says Arash Dahi Taleghani, associate professor of petroleum engineering at Penn State. “Being able to better pump cement through these very narrow spaces that methane molecules can escape from is the beauty of this work.
Taleghani and his colleagues made their new concrete by starting with sheets of graphite that are almost two-dimensional and treating them with chemicals, altering the nanomaterial’s surface properties so it is able to dissolve water, rather than repel it. The graphite is then uniformly fed into the cement slurry, where the new properties are key to the strength of the resulting material.