Experimental Analysis on Depressurization-induced Gas Production from 10-Meter-scale Hydrate-bearing Sediments

The depressurization-induced production behavior of 10-meter-scale methane-hydrate-bearing sediments was experimentally investigated in order to explore the field application of depressurization control. The design factors were the depressurization rate and its size (i.e., the depressurization degree). An unconsolidated sedimentary sample in 10-meter-scale apparatus followed grain-size distribution similar to that of a sandy layer in a real hydrate field. Unlike small-scale experiments, the dissociation propagation with depressurization was markedly observed. The depressurization degree significantly influenced hydrate dissociation, while the depressurization rate dominated the dissociated gas flow and strongly affected the recovery. The experimental results realistically described depressurization-induced gas production occurring in the actual field.