Vol.7 No.4 2015
Research paper : Applicability of the technologies to the assessment of methane hydrate sediments (N. TENMA)−219−Synthesiology - English edition Vol.7 No.4 (2015) systematization of research. In this paper, I will discuss the progress made in evaluation technologies for sedimentary characteristics, concentrating on the topics handled by the Reservoir Simulator Team. 2 The work of the Methane Hydrate Resource Development Research Consortium (MH21)In the Phase 1 period of FY 2001 to 2008, MH21 yielded many results, such as the calculation of the resource assessment for methane gas in the MH layer in Eastern Nankai Trough region and the successful continuous production by depressurization method in the onshore production test at Canada. Phase 2 was launched in April 2009, with a scheduled completion date in FY 2015, “for evaluating at high reliability the potential for the methane gas in the MH layer to be used as an energy resource and for identifying the technological challenges necessary to organize the technologies for commercial development of the MH layer, through R&D such as the offshore production test in the coast of Japan.” In Phase 2, Associate Professor Yoshihiro Masuda of the University of Tokyo was appointed the Project Leader. The R&D is being conducted by the Research Group for Field Development Technology, the Research Group for Production Method and Modeling, the Research Group for Resource Assessment, and the Group of Administrative Coordination in MH21. In March 2013, the first offshore production test was conducted for the first time in the world in the Daini Atsumi Knoll of the Eastern Nankai Trough. This test was conducted: (1) to demonstrate that gas can be produced from hydrates by the depressurization method and to confirm gas productivity, and (2) to establish the technology needed to apply the depressurization method at relatively shallow depths below the seabed floor. About 120,000 m3 of gas was produced in six days using the depressurization method. Valuable data was also obtained for reservoir evaluation. Based on the data obtained in this field test, various research groups and teams are currently collaborating and conducting detailed investigations into the diverse phenomena of the MH layer.Similar research is in progress around the world, such as in the United States, Korea, China, and India. For example, Korea is engaging in a gas hydrate survey in the Tsushima Basin, and the US is surveying reserves, along with the earthquake exploration surveys, in the Gulf of Mexico, however, no offshore production tests have yet been conducted.As the administrator of the Research Group for Production Method and Modeling, MHRC engages in R&D for various production methods, including the depressurization method. In Phase 1, several production methods, including depressurization and heating methods, were investigated. The depressurization Fig. 1 Mechanical behavior of the MH layerIt is predicted that sediment deformation will occur by the MH dissociation and consolidation during the depressurization operation.Flow of gas/waterConsolidation and deformationDissociation area due to depressurization methodSeabed surfaceMH layerLower layerUpper layerMethane Hydrate Research Center, AISTMH21※Total 18 universities and companies participate in the Research Group for Production Method and Modeling.Main research themes of the Research Group for Production Method and ModelingEvaluation technologies for sedimentary characteristicsEvaluation technologies for productivity and production behaviorTechnologies for advanced production methodsResearch Group for Production Method and Modeling (Administrator: AIST, MHRC)Research Group for Field Development Technology(Administrator: JOGMEC)Deputy Director of Research CenterAdministration of the MH Research AllianceDirector of Research CenterProduction Technology TeamPhysical Property Analyses TeamReservoir Simulator TeamMethane Hydrate Reservoir TeamGroup of Administrative Coordination (Administrator: JOGMEC)Research Group for Resource Assessment (Administrator: JOGMEC)MH21 Steering CommitteeFig. 2 Relationship between the Research Group for Production Method and Modeling and the Reservoir Simulator Team, and research themesIn the Methane Hydrate Resource Development Research Consortium (MH21), the Methane Hydrate Research Center (MHRC) oversees the R&D as the administrator of the Research Group for Production Method and Modeling. The Reservoir Simulator Team engages in the development of evaluation technologies for sedimentary characteristics as a research team within the MHRC.