油層エンジニアから見たメタンハイドレート研究開発の現状と今後

抄録

Natural gas hydrates have huge potential as an unconventional gas resource. It is necessary for utilization of these resources to establish a gas production technology and investigate suitable conditions for extraction of methane gas from gas hydrate bearing reservoirs. In this paper, the main outcomes of past field tests for gas hydrate production are briefly introduced. Also, this paper describes current status of gas hydrate production R&D that include initial physical properties and their changes of gas hydrate reservoir due to gas hydrates dissociation by depressurization, and pressure-temperature monitoring systems and reservoir simulation as the technologies to evaluate reservoir response during the field production test.

Many methods have been proposed for gas production from the gas hydrate reservoir, but production methods superior to the depressurization have not been proposed at the present time. The stable and long-duration production by depressurization has not been accomplished yet. It is important not only to understand possible phenomena during production but also to identify unknown problems to be overcome and examine practical countermeasures for them.