Scientists from the Lawrence Berkeley National Laboratory (Berkeley Lab) have built the world’s first x-ray computed tomography (CT) scanner able to look at core samples directly from remote drilling sites.
The portable device, which employs the same high-resolution imaging technology used to diagnose diseases, could help researchers determine how to best extract the vast quantities of natural gas hidden under the world's oceans and permafrost. The scanner images the distribution of gas hydrates in core samples pulled from deeply buried sediment.
Until now, core samples had to be sent to laboratories for analysis, which means it was a slow and difficult process.
Barry Freifeld, a mechanical engineer in Berkeley Lab's Earth Sciences Division, wondered if real-time, on-site analysis could expedite this work. His optimism stemmed from earlier research in which he demonstrated that a medical CT scanner can image a wave of methane hydrate dissociating in a sand mixture.
Unfortunately, most CT scanners weigh more than one ton. So Freifeld built a refrigerator-sized, 300-kilogram scanner. And they installed it on the JOIDES Resolution Drill Ship operated by the Ocean Drilling Program.
Here is a photograph of this portable scanner.
"We can run core through the scanner almost as quickly as they can pull it out," says Freifeld "Now, researchers don't have to send kilometers of core to a lab to get the same information they can obtain in the field. They'll send data instead of rocks."
This winter, the hearty scanner traveled above the Arctic Circle to the permafrost stretches near Prudhoe Bay, Alaska. There, researchers are conducting the first test on U.S. soil concerning how to extract methane from gas hydrates. The scanner analyzed more than 500 feet of core sample, enabling researchers to generate the most detailed log of permafrost cores ever recorded.
And the scanner will continue to travel and explore the oceans.
It's scheduled for another hitch aboard the JOIDES Resolution as it sails from Bermuda to Newfoundland. The ship will drill along the continental margin and study rifting, the tectonic process by which the lithosphere thins and the seafloors spread. The scanner will allow scientists to generate the most detailed lithostratigraphic record ever constructed from oceanic cores.
Source: Lawrence Berkeley National Laboratory, June 13, 2003
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