TOKYO, April 10 (Reuters) - Japan's trade ministry said on Monday it has begun preparations for a second production test to extract methane gas from methane hydrate deposits offshore Japan's central coast.
The test is the first since Japan achieved the world's first extraction of gas in 2013 from offshore deposits of methane hydrate, a frozen gas known as "flammable ice".
Japan, which imports nearly all of its energy sources, has been aiming to launch private sector commercial production of methane hydrates by between 2023 to 2027, but the goal will still be a challenge as many obstacles remain to be solved, officials at the Ministry of Economy, Trade and Industry (METI) said.
Japan's government has budgeted around 20 billion yen ($180 million) for offshore production experiments, said Yuki Sadamitsu, Director of the Oil and Gas Division at the trade ministry's Agency for Natural Resources and Energy.
Japan is the world's top importer of liquefied natural gas (LNG) and the need for domestic gas resources has become greater since the Fukushima nuclear crisis two years ago shut down most of its nuclear power generation and sharply raised fossil fuel imports such as LNG and coal.
METI said the production tests will be carried out by two wells and will continue for a combined four to five weeks. The first production well in 2013 ended abruptly in less than a week due to problems with sand flowing into the well.
Methane hydrate is formed from a mixture of methane and water under certain pressure and conditions. Governments including India, Canada, the United States and China are also looking at exploiting hydrate deposits as an alternative source of energy, Sadamitsu said.
In 2008, Japan Oil, Gas and Metals National Corp (JOGMEC) successfully demonstrated a nearly six-day continuous period of onshore production of methane gas from hydrate reserves held deep in the permafrost in Canada.
A Japanese study has estimated the existence of at least 40 trillion cubic feet (1.1 trillion cubic meters) of methane hydrates in the eastern Nankai Trough off the country's Pacific coast, equal to about 11 years of Japanese gas consumption. ($1 = 111.4300 yen)