Fig. 2 . Initial hydrate reservoir conditions in all cases.
3.1 Methane–containing fluid flow characteristics inhydrate–bearing
reservoirs
The free methane gas in the deep ocean floor is bound to migrate upward,
and the gas migration also drives the movement of seawater in the
sediments (Su et al. , 2012). We simulate gas–water migration by
injecting gas and water into hydrate–bearing sediments, the
experimental conditions of Cases 1–3 are shown in Table 2. The inlet
pressure is increasing at the beginning, and large gas–water flow rate
makes inlet pressure increase faster, as shown in Fig. 3, because the
injection velocity of gas–water is larger than the seepage velocity of
hydrate–bearing sediments. In Case 1, the methane gas and seawater were
injected into the hydrate–bearing reservoir at the flow rate of 4–1
ml/min. After 52 min, the inlet pressure decreased, and the inlet
pressure kept the same with outlet pressure at 136 min, fluids flow
through the reservoir smoothly. The outlet flux curve of Case 1
increased and seawater flowed out of the reactor continually, indicating
the hydrate reservoir had no sealing effect during gas–water flow
process in Case.
Table 2. Experimental conditions and results of Cases 1–3.