Leaky gas wells are more than a waste of natural resources and a key player when considering their effect on climate change via leakage of methane into the atmosphere.
Engineers at Penn State University have created the latest kind of malleable cement they claim can help contain the problem by plugging leaks that typical cement cannot fill. While massive gas leaks are usually taken care of to immediately, tinier ones can go unidentified for a prolonged time, even years. Fixing the damage was never this easy.
With these wells sometimes spreading for miles underground, changes in temperature and pressure can result in cracks in the cement initially used to tighten the pipes and hold the gas, allowing it to filter through into waterways or released into the atmosphere.
“In construction, you may just mix cement and pour it, but to secure these wells, you are cementing a part that has the width of less than a millimeter, or like a piece of tape,” states Arash Dahi Taleghani, associate professor of petroleum engineering at Penn State. “To manage to improve pumping cement in the middle of these fragile spaces that methane molecules can come out from is the success of this work.”
Taleghani and his partners created their latest concrete by beginning with graphite sheets that are supposedly two-dimensional and curing them with chemicals, changing the nanomaterial’s apparent properties. Hence, it can dissolve water instead of repelling it. The graphite is then evenly fed into the cement slurry, where the changed properties are significant to the new material’s strength.
“If we only pour this material in the water and mix it, these tiny particles have the ability to stick together and form a conglomerate,” Taleghani added. “If they are not spreading evenly, then the graphite is not as powerful inside the cement.”
The team continued experiments utilizing what they call narrow-slow tests to test the latest cement performance, where it was accurately used to close gaps measuring just 120 microns in width. Other than sealing up leaking gas wells, the team states its new cement could be of use in carbon capture applications, as well.
Taleghani said that “We have developed a very flexible cement that is more impervious to cracking.” “That’s noteworthy because there are millions of orphaned and abandoned wells across the world, and cracks in the casings can allow methane to release into the environment.”