P.2 ~ Research effort aims to enhance cement integrity in deepwater

Improving cement integrity in deepwater applications is one of the primary foci of the National Energy Technology Laboratory (NETL), a division of the US Department of Energy. Within NETL's national laboratory system, under the direction of the Office of Research and Development, and in concert with industry and academia, work is advancing in many areas, from reverse circulation cementing to smart cement.

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Nano impregnated cement

Honolulu-based Oceanit Laboratories Inc., supported by DOE funding, is exploring oil and gas well applications for its nanotechnology concrete mix that was created as a means for strengthening material for use in buildings, bridges, and roads.

Companies worldwide are working on ways to incorporate so called carbon nanotubes into concrete. In addition to increasing toughness, the nanotubes, which are thousands of times thinner than a human hair, are highly conductive. That means that they could be used to create a kind of nervous system within concrete that could be used to detect cracking and weaknesses in structures.

However, many hurdles remain in the path of the promising technology, including high costs and technical barriers such as how to create a commercial nanoconcrete manufacturing process. Oceanit has worked to solve a key problem — how to homogeneously mix the tiny nanotubes into a thick fluid such as cement. The company is seeking to patent a process in which nanotubes are suspended in a liquid concentrate that is added to the water used to make cement.

The company is developing technology for road and bridge use in coordination with state and county transportation officials. Initially, the nanoconcrete would be tested for durability and strength. Ultimately, the company hopes the technology will revolutionize the way the structural integrity of concrete is monitored, though that application could take some time to develop.

"The carbon nanotube mixture we're patenting acts like a spider web within the concrete," said Oceanit spokesman Ian Kitajima. "Stresses in the concrete material are sensed by this internal web. Small pulses of electricity are sent through this nano-web within the concrete. Changes in the web reflect changes in cement structure, which affects the return signal that could be used to determine the health of a building."

For now, any use of nanotechnology in cement will be limited to specialized applications because nanotubes cost more than their weight in gold. "It is a very expensive material today, but it's being produced in higher and higher quantities every year," Kitajima said.

Potential transportation applications include portions of roadways and bridges that need stronger construction material or require more intensive monitoring, said Barry Fukunaga, director of the Hawaiian Department of Transportation. "It's a real innovative kind of a product that they've come up with," he said. "It's the kind of thing where it may be more costly, but in certain applications it could be a good investment because of its durability and sensing qualities."

Through the current DOE partnership, Oceanit is studying deepwater and problematic well cementing applications.

Editor's Note: For further information about the "smart cement" project or the deepwater reverse-circulation primary cementing project, contact Bill Head at RPSEA (bhead@RPSEA.org/281-313-9555) or C. Vipulanandan at the University of Houston (cvipulanandan@uh.edu/713-743-4278). For further information about the nano impregnated cement project, contact Roy Long at NETL (roy. long@netl.doe.gov/281-494-2516) or Vinod Veedu at Oceanit (vveedu@oceanit.com/713-357-9622).

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