Abstract: Depressurization in conjunction with warm water injection with dual horizontal wells was employed to investigate the gas production performance of hydrate dissociation in a cubic threedimension simulator. Based on the process of pressure and temperature changing with time, the experiment can be divided into four sections,i.e. the free gas release stage, the quiescence stage, the depressurization stage and the injection stage. The experimental results showed that hydrates formed a second time in the free gas release stage and the quiescence stage. In the injection stage, the hydrate was dissociated under the synergistic effect of depressurization and thermal stimulation. The change of the hydrate/gas/water saturation indicates that the hydrate can be dissociated completely. In addition, the energy ratio in this study is higher than that in the previous study by the vertical well with the Huff and Puff method.

Key words: three dimension, hydrate, dissociation, combined method；dual horizontal wells, heat transfer characteristic