多孔介质中泡沫的迁移特性和影响因素研究

通过设计一系列模拟柱实验探讨了泡沫在非饱和多孔介质中的运移特征以及泡沫质量、泡沫注入速率、介质渗透率对泡沫注入压力的影响.研究表明:泡沫气体锋面、泡沫液体锋面与泡沫锋面在多孔介质中是分离迁移的,且迁移速度大小关系为泡沫气体锋面泡沫液体锋面泡沫锋面;泡沫锋面相对于泡沫气体锋面的延迟系数为2.0.在泡沫运移过程中,模拟柱中压力的产生主要发生并均匀分布在泡沫覆盖区域中,固定点处压力随时间呈直线增加趋势;泡沫在1~1.2mm介质中的有效粘度为85.49m Pa·s,是水在介质中运移有效粘度的84.64倍(水的有效粘度为1.01m Pa·s).由此可知,泡沫注入模拟柱时需要较大的压力,主要是由于泡沫的有效粘性较大引起的.介质渗透率对泡沫注入压力的影响主要取决于泡沫注入速率;当单位面积泡沫注入速率相同时,泡沫注入压力随介质渗透率增大而降低.当泡沫质量为91.4%时,当泡沫注入速率由2.1m L/min升高至3.2m L/min与4.4m L/min时,压力梯度由26.95psi/m升高至30.74与46.40psi/m,而当泡沫注入速率为3.2m L/min时,当泡沫质量由93.5%降低至91.4%与88.2%时,压力梯度由30.16psi/m升高至30.74与34.57psi/m,由此可知,泡沫质量与泡沫注入速率均对泡沫注入速率产生影响,然而泡沫注入速率的影响大于泡沫质量对注入压力的影响.

Study on transport characteristics of foams and affecting factors in porous media

A series of column experiments were conducted to investigate the transport characteristics of foam in unsaturated porous media and influences of foam quality, foam injection rate, and media permeability on the injection pressure. The results indicated that the foam front, liquid-wetting front, and foam gas front were separated during the transport in porous media and their relationship of transport rate is foam gas front > liquid-wetting front >foam front. The foam transport had a retardation of 2.0 relative to the gas flow. The pressure primarily occurred and uniformity distributed in the foam-occupied region, and the pressure showed a linear increasing trend over time in a certain location. The calculated effective foam viscosity in 1-1.2 mm porous media was 85.49 mPa s, which was 84.64 times greater than the viscosity of water into the same sediment. Due to the higher effective foam viscosity, the greater injection pressure was needed. The influences of media permeability on foam injection pressure mainly depend on the foam injection rate. Foam injection pressure decreased with increment of media permeability while the foam injection rate was same in per unit area. When the foam quality was 91.4%, the pressure gradient increased from 26.95 psi/m to 30.74 and 46.40 psi/m when the foam injection rate increased from 2.1mL/min to 3.2 and 4.4 mL/min, respectively. When the foam injection rate was 3.2mL/min, the pressure gradient increased from 30.16 psi / m to 30.74 and 34.57 psi/m when the foam quality reduced from 93.5% to 91.4% and 88.2%, respectively. Both foam quality and foam injection rate exert impact on injection pressure, however, foam injection rate has a more profound influence than foam quality on injection pressure.