Cracking under pressure is no problem for high strength self-healing cement

February 14, 2017, Pacific Northwest National Laboratory
Cracking under pressure is no problem for high strength self-healing cement
When geothermal wells are made using PNNL-developed self-healing cement, cracks and breaks in the well can heal automatically. This technology has the potential to eliminate excavation, repair, and replacement costs associated with cracked cement wells. Credit: Pacific Northwest National Laboratory

With an average life span of 30-40 years, the cement around geothermal production wells eventually cracks over time. Because wells with cracked cement are vulnerable to leakage, reduced strength, and corrosion, it's important to repair them in a timely fashion. However, repairs can easily top $1.5 million dollars; the cost of new materials, excavation, installation, and halting power production adds up fast.

Researchers at PNNL developed that can heal itself when cracks occur. Using self-healing cement for geothermal wells would save millions of dollars and would reduce the amount of downtime necessary for repairs.

Super to the Power of Three

PNNL chemist Carlos Fernandez and his team discovered that by adding a strong and flexible and powerful ingredient, called polymers, they could create self-healing cement. Naturally found in the , plant structures, and more, these large, chain-like molecules work to hold substances together. The team discovered by mixing in 5 to 20 percent of man-made polymers into typical cement before it is poured and cured, the cement can repair itself when cracks occur.

PNNL's research team has successfully proven this cement can repair itself in a few days, and they predict it has the potential to heal itself in just a matter of hours. Just as impressive, is the cement's projected ability for continuous self-healing, meaning it can repair itself many times over and maintain the rheological and mechanical properties necessary for geothermal wells.

Explore further: Cracks in abandoned wells could hinder carbon sequestration efforts

Related Stories

Effect of CO2 on the integrity of well cement examined

March 5, 2013

Geologic carbon storage is the separation and capture of carbon dioxide (CO2) from large stationary sources, such as power plants, followed by injection into deep geologic formations. Long-term storage of CO2 pre-supposes ...

Recommended for you

Apple closing iPhone security gap used by law enforcement

June 14, 2018

Apple is closing a security gap that allowed outsiders to pry personal information from locked iPhones without a password, a change that will thwart law enforcement agencies that have been exploiting the vulnerability to ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.