3.3 Effects of hydrate saturation change on the sealing layer formation process
In Cases 3, 4, 5, the inlet pressure increased as soon as the gas–water flowed, indicating the hydrate–containing sealing layer formed at the beginning. Thus, we investigated the effects of hydrate saturation change on sealing layer by increasing seawater injection rate radio, the experimental conditions of Cases 6 and 7 are shown in Table 4. When seawater flow in hydrate reservoir was enhanced, the reservoir won’t produce sealing effect during flow process. The gas–water process was divided into two stages (see Fig. 10): in the first stages the gas–water flow rate was 1–2 ml/min, in the second stage, the gas–water flow rate was 2–0.5 ml/min in Case 5 and 4–1 ml/min in Case 6, respectively.
Table 4. Experimental conditions and results of Cases 6 and 7.