Japanese test coaxes fire from ice (Methane Hydrates)
David Cyranoski
23 April 2013
Methane flowing from beneath the sea floor has buoyed Japan’s hopes for securing its own plentiful energy source. A pilot project 80 kilometres off the country’s shores produced tens of thousands of cubic metres of gas — and reams of useful data — before a clogged pump brought the project to an abrupt end last month.
Reservoirs of methane hydrates — icy deposits in which methane molecules are trapped in a lattice of water — are thought to hold more energy than all other fossil fuels combined. The problem is extracting the methane economically from the deposits, which lie beneath Arctic permafrost and seafloor sediments. But some scientists and policy‑ makers in energy-poor, coast-rich Japan hope that the reservoirs will become a crucial part of the country’s energy profile.
Engineers have had some limited success in extracting methane from underneath Canadian tundra. But tapping the richer marine deposits presents a host of challenges, among them the fact that whereas oil and natural gas exist in deep reservoirs, methane hydrates are found in the first few hundred metres of the sea bottom where sediments are loose, making wells unstable and putting them at risk of clogging by sand.
The test, run by the Tokyo-based state oil company Japan Oil, Gas and Metals National Corporation (JOGMEC), took place in waters 1 kilometre deep, where the research drilling ship Chikyu had bored through 270 metres of sediment to reach a 60-metre-thick methane hydrate reservoir. On 12 March, a pump reduced the pressure in the deposit, unlocking the gas from its icy cage. Gas started flowing up from the sea floor to a platform on the ship, where it produced a roaring flame. “Being Japanese, you might have thought we would have yelled ‘banzai’ or something,” says project director Koji Yamamoto. But he says that he was too busy staring at displays of crucial data showing the pressure at the bottom of the well and the flow rate and composition of the incoming gas.
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http://www.nature.com/news/japanese-test-coaxes-fire-from-ice-1.12858
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