Experimental study of methane hydrate dissociation and gas production behaviors under depressurization

The objective of this study is to evaluate into detail on the effect of sensible heat in methane hydrate cores for gas production behavior using depressurization method under various initial temperature conditions. Firstly, methane hydrate was synthesized under low temperature and high pressure conditions in the laboratory. Methane hydrate cores were made by using methane hydrate and sand. Dissociation experiment using those cores was conducted by using depressurization method. Then, pressure, temperature, gas production rate and cumulative gas production were measured during the experiment. In the experiment, gas production rate of low porosity core with T_ini of 2.5°C was higher than that of low porosity core with T_ini of 1.5°C in the first 10 minutes. That implies sensible heat used for methane hydrate dissociation in the low porosity core with T_ini of 2.5°C was higher than that in the other core due to initial temperature deference between these low porosity cores. Therefore, it is important to increase initial temperature of methane hydrate reservoir for enhancement of gas production rate under depressurization.