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To put up an oil rig, follow that clam

A digging device inspired by razor clams could help anchor offshore oil rigs, and has netted $6.5 million of oil industry funding

Video: To put up an oil rig, follow that clam…

To put up an oil rig, follow that clam

AMOS WINTER, a graduate student at the Massuchusetts Institute of Technology, has a new skill to add to his resumé. “Amos is now a licensed clam digger in the state of Massachusetts,” his supervisor, Anette Hosoi, says proudly.

Razor clams retreat rapidly into the sand when threatened, making them elusive prey. The clams move with ease into muddy silt and gravelly sand, despite being able to exert a force only one-tenth that required for a person to push a clam shell into the sand. Winter dug up some clams to observe their uncanny burrowing ability, and then built a “roboclam” that is able to burrow into the sand by mimicking their action.

“That’s what got the oil industry interested,” says Hosoi. If the clam’s technique can be replicated mechanically, it could prove ideal for anchoring offshore rigs in the soft seabed of the Gulf of Mexico and other oil-rich waters around the world.

So how do the clams do it? A slowed-down video of a clam digging offers some clues. The clam first braces itself by opening its long shell, then extends its muscular foot forward. Then it partly closes its shell and backs off, which temporarily loosens the sediment in front. The clam then darts forward, gaining ground in the process.

The roboclam is one of several ongoing MIT projects being sponsored by energy multinational Chevron to the tune of $6.5 million over the next five years – it is also partially funded by Bluefin Robotics of Cambridge, Massachusetts. Chevron’s motivation grows more obvious with every hike in oil prices. The industry is hoping that sooner or later that the ban on offshore drilling will be lifted. Last month, both US president George Bush and presidential candidate John McCain advocated lifting the ban, as did Florida governor Charlie Crist, whose state has large offshore oil reserves.

Opponents say such drilling will threaten marine ecosystems and coastal fisheries while doing nothing to relieve the immediate energy crunch. But with US gasoline prices averaging over $4 per gallon, the oil industry’s enthusiasm for deep-water reserves is running high – though getting the oil out presents a major challenge.

“As we move to deeper water everything becomes harder and vastly more expensive,” says Owen Oakley, a consultant with the research arm of Chevron. The high pressures and low temperatures at depths greater than 2500 metres will require more robust equipment and better communications. So the order-of-magnitude leap in digging efficiency demonstrated by the razor clam would be of great benefit to anchoring systems, which are heavy and costly to deploy.

The roboclam will be tested in the field this autumn. Hosoi admits the roboclam may not scale up to oil-rig proportions, but even so it could be used to anchor and move smaller pieces of equipment on the seabed. The industry is interested enough to keep funding the work. “These are not people worried about the end of oil,” she says.

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