胶态微泡沫用于冲洗含水层的迁移分布特征

目前有关胶态微泡沫（CGAs）冲洗含水层过程中的迁移分布特性尚不明确，本研究利用二维模拟实验详细探究了注入速率、表面活性剂浓度和介质条件对CGAs迁移分布时空变化特征的影响.结果表明，在单侧单点注入条件下，CGAs的波及区域形状近似半圆形，迁移锋面相对规则；CGAs破裂产生的泡沫液分布在其迁移锋面四周，泡沫气体受地下水浮力影响向上方迁移，导致出现在纵向向上迁移距离大于向下迁移距离的"向上漂移"现象.表面活性剂浓度对CGAs的迁移分布影响较小；注入流速低或介质渗透性差，CGAs均会在迁移后期出现明显的“向上漂移”现象，同时其波及区域形状逐渐趋向于半椭圆形；恒定流量注入CGAs，其在含水层中的波及面积存在最大值.相对传统液相冲洗液，CGAs在非均质含水层中迁移分布较为均匀，受介质非均质性影响较小.

The migration and distribution characteristics of colloidal gas aphrons during its flushing of aquifer

At present, the migration and distribution characteristics of colloidal gas aphrons (CGAs) during the flushing of aquifers are not clear. In this study, the effects of injection rate, surfactant concentration and media conditions on the spatial and temporal variation characteristics of the migration and distribution of CGAs were investigated in detail using two-dimensional simulation experiments. The results showed that under single-point and single-side injection conditions, the shape of the sweeping area of CGAs was approximately semi-circular, and the migration front was relatively regular. Besides, the foam liquid generated by the bursting of CGAs was distributed around its migration front, and the foam gas migrated upward due to the influence of groundwater buoyancy, resulting in the "drift up" phenomenon that the upward migration distance in the vertical direction was greater than the downward migration distance. As for surfactant concentration, it had little effect on the migration and distribution of CGAs. When the injection velocity was low or the permeability of the media was poor, CGAs appeared an obvious "drift up" phenomenon in the later stage of migration, at the same time, the shape of the sweeping area gradually tended to be semi-elliptical. There was a maximum sweeping area in the aquifer when CGAs were injected at a constant flow. In all, compared with traditional liquid flushing fluids, the migration and distribution of CGAs in the heterogeneous aquifer was relatively uniform and less affected by the heterogeneity of the media.