AIST Stories No2

23AIST in present day living! at a glanceTerminologyresult, AIST and the Japan Oil, Gas and Metals National Corporation established a research consortium that has been engaged in evaluation and development of technologies to produce natural gas from methane hydrate resources. To date AIST has studied various methods for stimulating methane hydrate in order to gasify it including, the Hot Water Injection Process*2 and the Inhibitor Injection Process*3. AIST has explored efficient methods by developing its own simulator, for example, and as a result it ended up adopting the Depressurization Method. In 2008, it succeeded in producing approximately 2,400 m3/day in an onshore production test in Canada.Energy security through swift commercializationThe Methane Hydrate Research Center was set up in AIST in 2009. The center has undertaken such work as analysis of sand layers that contain methane hydrate, and synthesis of methane hydrate containing sandy sediment to advance preparations for offshore production test. Subsequently, in 2013, the world’s first offshore test was carried out. This test succeeded in producing an average of 20,000 m3 of natural gas per day, which was a much larger quantity than in the test in Canada. In commercialization as an energy resource, natural gas must be produced in a reliable and long-term manner with an energy content that exceeds that required for production. Regarding production rate, at least several tens of thousands cubic meters is required for the commercial production.Obstacles to production have been identified at present, such as sand flowing into the well. On this account, AIST is prioritizing development of commercial-scale production technology that is reliable over the long term. Currently, the effectiveness of the newly developed Ultra-depressurization Method *4 is being verified. Although AIST is the sole research institute with all of the required core equipment related to this production technology, the USA, China and South Korea are currently making great strides. Shale gas is another area of note, with development centered on the USA. Rapid commercialization of methane hydrates through corporate participation is an urgent issue for Japan to maintain its advantage.“If methane hydrates can be developed, Japan will needless to say boost its energy security but further, we also believe that construction of marine pipelines, for example, in the surrounding areas will rejuvenate Japan’s maritime industry and create new industries.”Methane hydrateDepressurization MethodAn icy substance found in and/or under seabed areas comprised of methane gas, which is the main component of natural gas. Also known as fiery ice because it combusts when lit. It exists in permafrost regions and in seabed areas in continental fringes that are deeper than 500 m. The quantity of methane incorporated is equivalent to approximately 160-times its gaseous volume. Methane hydrate is expected to become a next-generation natural resource; currently, various countries are proceeding with development of methane hydrate resourcesBy drawing up the water in the drilled well and reducing the pressure in the methane hydrate layer, dissociation of methane hydrate is accelerated, the methane gas and seawater that flow into the well are separated, and methane gas is recovered at the surface.*1 Depressurization Method: A method to stimulate solid methane hydrate and thereby gasify it. Refer to Terminology at a glance. *2 Hot Water Injection Process: A method that heats methane hydrate to break it down. *3 Inhibitor Injection Process: A method entailing injection of alcohol to accelerate dissociation. *4 Ultra-depressurization Method: A variation of the Depressurization Method: this method reduces pressure even more, to less than 30 atm, in order to accelerate dissociation. There is a high probability that production quantities can thereby be doubled.◀Geological sampling at sea. Pumping up waterPumpMethane gas recoveryMethane gas recoveryDissociationthroughdepressurizationDissociationthroughdepressurizationMethane hydrate layerWater level inside the well is lowered to reduce pressure on the methane hydrate layerMethane hydrate is dissociated due to depressurization and methane gas is formedDepressurization Method principleImpact in the following fields! Community lifeIndustry◦Residential◦Safty and security◦ Environment, resources, energy◦Materials◦Chemistry