可燃冰能充当日本的能源救世主吗？

    到目前为止，日本国家石油天然气和金属公司( Japan Oil, Gas and Metals National Corporation )一直肩负钻探甲烷水合物之责，但这家公司表示，一旦试钻于2016年至2018年之间某个时候完成，私人公司将接管钻探业务。

    日本钻探队表示，他们向海浪下1公里处发送了一台被官员称为“挖掘机”的机器，从而破解了技术难关。在海下，这台机器把固化的甲烷水合物分解为水和天然气，然后将天然气传送至海平面。

    日本国家石油天然气和金属公司甲烷水合物研究团队的项目总监山本浩二解释：“我们给甲烷水合物钻了一些孔，生成水，以减少压力，从而使甲烷从冰状物质中分离，向上流动至井口。”

    虽然一些人欢迎一种全新能源供应的潜在好处，但其他人指出，钻探冷冻气体构成的不稳定床体有一定的危险性，会给大气增添更多的二氧化碳。

    “从海床下释放大量甲烷的想法吓坏了许多环保人士，”鲁德哈特能源咨询公司(Roodhart Energy Consultancy)主管利奥•鲁德哈特表示（甲烷是一种温室气体，其强度比二氧化碳大20倍）。

    “虽然相比于煤或石油，甲烷是一种更加清洁的化石燃料，但尚未利用的甲烷水合物其实是‘被捕获的’温室气体，一些人认为它们应该继续被锁定在海下。开采甲烷冰也可能对海洋生态系统造成严重破坏。”

    山本浩二并不认为存在这种井喷或重大环境破坏的危险，尽管一个小规模的甲烷水合物井喷与此前英国石油公司(BP)的墨西哥湾漏油事件有关。纵观历史，从包合物床体大规模释放甲烷——这种活动被称为“包合物枪”——一直是造成大规模灭绝事件的原因之一。

    研究人员并不认同与出于商业能源使用的甲烷水合物勘探相关的风险。海洋学家，莱斯大学(Rice University )教授杰拉尔德•狄更斯同意日本研究团队的观点。他认为，人类活动几乎不可能造成如此大的灾难。

    “与钻探有关的唯一一个潜在问题是，在天然气水合物的正下方是否存在承受过大压力的气体，”狄更斯说。“然而，越来越多的理由促使我们相信，这种事情其实不可能发生。所以，就钻探而言，应该是没有问题的。”

    甲烷水合物领域的顶级专家、美国地质调查局(United States Geological Survey)的蒂姆•科利特认为，自然和人类引发的改变有可能导致水合物失去稳定性，造成灾难性滑坡。

    2004年，他在出席美国国会听证会时声称：“在美国大西洋沿岸和北欧沿岸已经发现了一些涉及天然气水合物引发海底滑坡的证据。这些活动可能给地球的海洋和大气释放出大量甲烷。”（财富中文网）

    译者：任文科   

    The state-owned Japan Oil, Gas and Metals National Corporation (JOGMEC) is behind the successful methane hydrate drillings so far, but it says private companies will take over once test drilling finishes sometime between 2016 and 2018.

    The Japanese team say they have cracked technical difficulties by sending down what officials describe as "an excavator" one kilometer below the waves. There the machine separates solidified methane hydrate into water and natural gas, and funnels the gas up to the surface.

    "Holes are drilled into the methane deposits to produce water to decrease the pressure, allowing the methane to separate out from the ice-like material and flow up the wellhead," explains Koji Yamamoto, project director of JOGMEC's Methane Hydrate Research Team.

    While some welcome the potential benefits a new supply of energy, others point to the dangers of tampering with unstable beds of frozen gas and adding more CO2 to the atmosphere.

    "Environmentalists are horrified by the idea of releasing huge quantities of methane from under the seabeds," says Leo Roodhart, director of the Roodhart Energy Consultancy. (Methane gas is a greenhouse gas that's 20 times more potent than carbon dioxide.)

    "Although methane is a cleaner-burning fossil fuel than coal or oil, the as-yet untapped methane hydrates represent 'captured' greenhouse gasses that some believe should remain locked under the sea. The mining of methane ice could also wreak havoc on marine ecosystems."

    Yamamoto disagrees that there is any danger of such blowouts or major environmental damage -- although a small methane hydrate blowout was linked to the BP (BP) spill in the Gulf. Larger releases of methane from clathrate beds throughout history, known as the actions of a "Clathrate gun," have been responsible for mass extinction events.

    Researchers do not agree on the risks associated with methane hydrate exploration for commercial energy use. Oceanographer and Rice University professor Gerald Dickens agrees with the Japanese research team, arguing that there is little danger of such catastrophes coming from human action.

    "The only potential issue in regards to drilling would be if there is greatly over-pressured gas immediately beneath the gas hydrate," Dickens says. "However, there is growing belief and rationale to suggest that this cannot occur in nature. So, as far as drilling is concerned, there should be no issue."

    Tim Collett of the United States Geological Survey, a leading expert on methane hydrate, believes it is possible that both natural and human induced changes can lead to hydrate destabilization, triggering catastrophic landslides.

    "Evidence implicating gas hydrates in triggering seafloor landslides has been found along the Atlantic Ocean margin of the United States and off northern Europe," he told the U.S. Congress in 2004. "These processes may release large volumes of methane to the Earth's oceans and atmosphere."