From an environmental and safety standpoint, I'm not so sure:
Effect of hydrate phase transition during deep water drilling
When drilling in oil- and gas-bearing formations submerged in deep water, the reservoir gas may flow into the well bore and form gas hydrates owing to the low temperatures and high pressures found during deep water drilling. The gas hydrates may then flow upward with drilling mud or other discharged fluids. As they rise, the pressure in the annulus decreases and the hydrates dissociate into gas and water. The rapid gas expansion ejects fluid from the well, reducing the pressure further, which leads to more hydrate dissociation and further fluid ejection. The resulting violent expulsion of fluid from the annulus is one potential cause or contributor to what is referred to as a "kick".[32] (Kicks, which can cause blowouts, typically do not involve hydrates: see Blowout: formation kick).
Measures which reduce the risk of hydrate formation include:
High flow-rates, which limit the time for hydrate formation in a volume of fluid, thereby reducing the kick potential.
Careful measuring of line flow to detect incipient hydrate plugging.
Additional care in measuring when gas production rates are low and the possibility of hydrate formation is higher than at relatively high gas flow rates.
Monitoring of well casing after it is "shut in" (isolated) may indicate hydrate formation. Following "shut in", the pressure rises as gas diffuses through the reservoir to the bore hole; the rate of pressure rise will exhibit a reduced rate of increase when hydrates are forming.
Additions of energy (e.g., the energy released by setting cement used in well completion) can raise the temperature and convert hydrates to gas, producing a "kick".
Blowout recovery
Concept diagram of oil containment domes, acting as upsidedown funnels to pipe oil to surface ships. The sunken oil rig is nearby.
At sufficient depths, methane complexes directly with water to form methane hydrates, as was observed during the Deepwater Horizon oil spill in 2010. BP engineers developed and deployed a subsea oil recovery system over oil spilling from a deepwater oil well 5,000 feet (1,500 m) below sea level to capture escaping oil. This involved placing a 125-tonne (280,000 lb) dome over the largest of the well leaks and piping it to a storage vessel on the surface. This option had the potential to collect as much as 85% of the leaking oil but is previously untested at such depths. BP deployed the system on May 7–8, when it failed due to buildup of methane clathrate inside the dome; with its low density of approximately 0.9 g/cm3 the methane hydrates accumulated in the dome, adding buoyancy and obstructing flow.
http://en.wikipedia.org/wiki/Methane_clathrate#Hydrates_in_natural_gas_processing
Methane clathrates and climate change
Main article: Clathrate gun hypothesis
Methane is a powerful greenhouse gas. Despite its short atmospheric half life of 7 years, methane has a global warming potential of 62 over 20 years and 21 over 100 years (IPCC, 1996; Berner and Berner, 1996; vanLoon and Duffy, 2000). The sudden release of large amounts of natural gas from methane clathrate deposits has been hypothesized as a cause of past and possibly future climate changes. Events possibly linked in this way are the Permian-Triassic extinction event and the Paleocene-Eocene Thermal Maximum.
Climate scientists such as James E. Hansen hypothesize that methane clathrates in the permafrost regions will be released as a result of global warming, unleashing powerful feedback forces which may cause runaway climate change that cannot be controlled.
Recent research carried out in 2008 in the Siberian Arctic has shown millions of tonnes of methane being released with concentrations in some regions reaching up to 100 times above normal.
http://en.wikipedia.org/wiki/Methane_clathrate#Methane_clathrates_and_climate_change
I'm not trying to pick on Japan, but they have had on very recent disaster from a dangerous energy source and get excess pollution from the dust from China (it is called Hwangsa in Korean). I would hope the people of Japan are well informed of these issues before the gas is extracted.
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