Sand production behaviors during gas recovery from sandy and clayey‐silty hydrate‐bearing sediments: A comparative analysis

Sand production is a crucial geotechnical issue for safe and efficient gas recovery from natural hydrate (NGH) reservoirs. Although the same method of depressurization was chosen trials in Nankai Trough Northern South China Sea, their sand behaviors differed greatly due to skeleton diversity clayey-silt which resulted different control characteristics. In this study, we conducted experiments compare sediment responses these two typical hydrate-bearing sediments (GHBSs) before, during, after dissociation under depressurization. The results reveal fluid rates both GHBSs are relatively low before dissociation. However, rate sandy GHBS keeps stable at high value during whole period, accompanied by continuous sample subsidence. contrast, proved be only early stages clayey-silty with decreasing obviously afterward, subsidence exponentially decay until ultimate reached. After experiments, kinds particle plugging phenomena, bridge mud cake, found form outside screens GHBSs, respectively. Differences permeability, migration, characteristics thought main inducement variability types. These findings indicate that sand-production strategies should obey geological engineering integration differ according type. Specifically, concern risk dissociation, whereas more attention paid GHBS.