Depressurization and electrical heating of hydrate sediment for gas production

Abstract:

As a part of a Japanese National hydrate research program (MH21, funded by METI), we performed a study on electrical heating of the hydrate core combined with depressurization for gas production. In-situ dissociation of natural gas hydrate is necessary for commercial recovery of natural gas from natural gas hydrate sediment. Thermal stimulation is an effective dissociation method, along with depressurization.

To simulate methane gas production from methane hydrate layer, we investigated electrical heating of methane hydrate sediment. A decrease in core temperature due to the endothermic reaction of methane hydrate dissociation was suppressed and the core temperature increased between 1^oC and 4^oC above the control temperature with electric heating. A current density of 10A/m² with depressurization would effectively dissociate hydrate. Therefore, depressurization and additional electrode heating of hydrate sediment saturated with electrolyte solution was confirmed to enable higher gas production from sediment with less electric power.