The research on the residual saturation of a non-wetting phase fluid is one of the main focuses in the field of multi-porous media and multiphase flow. The saturation-capillary pressure (S-p) relationships and the residual air saturations were investigated under consecutive drying-wetting cycles in an air-water two-phase sandy medium. Results showed that, when the initial water saturation in the first imbibition process was close to that in the second imbibition process, the residual air saturation of the first imbibition process was also close to that of the second imbibition process. The residual air saturation increased with the increase of the initial water saturation in all the imbibition processes. The magnitude of the residual air saturation in the current imbibition was obviously affected by its former imbibition process. Large differences were also found between the residual air saturations predicted with the Land model and those measured in the column tests. It indicated that the effect of the initial water saturation on the residual air saturation was more significant than that of the circular number of the drying-wetting cycles.%通过对气-水两相细沙介质中干燥和湿润交替循环条件下饱和度-毛细压力(S-p)关系的测定,研究了不同初始条件下非湿润相流体剩余饱和度的变化规律.实验发现,在不同湿润过程中,相同级别初始水饱和度对应的空气剩余饱和度值较为接近；随着湿润过程中初始水饱和度的逐渐增大,其空气剩余饱和度呈升高趋势.在连续的干燥-湿润过程条件下,利用Land模型预测的非湿润相流体的剩余饱和度与柱实验实测值之间存在较大的误差.由此表明和干燥-湿润循环次数相比,初始水饱和度对空气剩余饱和度量级的影响要大,且后一个循环的空气剩余饱和度总受前一个循环的空气剩余饱和度的影响.
展开▼
