抄録
Gas production technology from natural gas hydrate is under investigation. Recently, the efficiency of depressurization method has been clarified by laboratory experiments and numerical analyses. However, the decrease of gas-production rate could occur during depressurization due to the temperature drop of the reservoir in the vicinity of production well. The solution to this problem is important for efficient and stable gas production from methane hydrate reservoirs.
In order to investigate the effect of ultrasonic irradiation on dissociation enhancement, experiments of methane-hydrate dissociation with ultrasonic irradiation are conducted under depressurized condition. Pressure vessel is originally designed for synthesizing methane hydrate sediments and for irradiating ultrasonic wave toward the synthesized sediments. Gas production rates are examined in the experiments of depressurization method and combined method of ultrasonic wave and depressurization. The efficiency of the combined method is evaluated by measured gas production rates. Results of the heat-balance calculations on the dissociation experiments are also reported.
