Development of Large Scale Production System for Methane Hydrates

Methane gas hydrate reservoirs have been recognized in a permafrost area and under a deep sea floor, in which the temperatures and pressures were in the equilibrium condition of methane gas hydrate. Methane gas hydrate distributed off the shores of Japan is valuable natural gas resources for the country. To utilize these resources, it is necessary to establish a gas production technology and investigate suitable conditions for production of methane gas from methane hydrate reservoirs. Experimentally the production technology and suitable conditions were investigated using the core samples which are artificially synthesized in a laboratory or naturally drilled from methane hydrate reservoirs. Although core-scale experiments give us the reproducible results on how methane hydrate dissociates under various conditions, a core-scale dissociation test in a laboratory can demonstrate the heat transport process. On the other hand, a dissociation of methane hydrates in an actual reservoir is dominated by the material flow process. Namely, the natural gas production behavior from methane hydrate reservoirs is dependent upon the size and characteristics of reservoirs, such as temperature and permeability. To couple data obtained from core-scale tests with the results of field-scale production tests, a large-scale production system in which dissociation experiments under the similar conditions of the actual reservoir can be conducted. In this paper, we describe the research objective of a large-scale production system for methane hydrate production tests established at the Methane Hydrate Research Centre of the National Institute of Advanced Industrial Science and Technology (AIST)