多孔介质两相系统毛细压力与饱和度关系试验研究

两相系统毛细压力-饱和度(h~S)关系曲线的确定是多孔介质多相流动研究的基础。采用简易试验装置对理想和实际介质中水-气和油-水两相系统中的h~S关系曲线进行了测定。试验结果表明,对于相同两相系统,多孔介质孔隙度愈小,同一毛细压力对应的饱和度相应愈大;对于不同两相系统,理想介质的关系曲线在一定毛细压力以下平缓,较大毛细压力时陡直,实际介质关系曲线走势相对较陡。分析结果表明,水-气和油-水两相系统的实测数据符合Parker等提出的基于van Genuchten(1980)关系式的折算理论;应用折算理论,可以在同一多孔介质某一两相系统h~S关系已知的情况下较好地估计同一孔隙度条件下其它两相系统的h~S关系曲线。

Experimental study of relationship between capillary pressure and saturation in two-phase system in porous media

The relationship between the capillary pressure and the saturation in two-phase system is the basis of gaining the relationship between the capillary pressure and the saturation in the multi-phase system.A simple and reliable setup is employed to obtain the relationship between the capillary pressure and the saturation of the water-air and oil-water system in the sand and soil samples.The experimental results show that,for a two-phase system with different porosity of porous media,the saturation is bigger with the reduction of porosity under the same capillary pressure;for different two-phase system with same dry bulk density,the curve of capillary pressure and saturation in sand appears flatter at less than a special capillary pressure value and steeper at the bigger capillary pressure.However,the curve of the capillary pressure and the saturation in soil seems steeper than in sand.The data analysis shows that the measured values of the water-air and oil-water system accord with the scaling method based on van Genutchen(1980) relation mainly proposed by Parker;and when the relationship between the capillary pressure and the saturation in one two-phase is known for a system with a specific porosity and a specific porous medium,those of other two-phase can be gained by using scaling method,and the estimated value is in better agreement with the measured one.