多孔介质水油两相系统相对渗透率与饱和度关系试验研究

Experimental study of the relationship between relative permeability and saturation in water-oil two-phase system in porous media

相对渗透率和饱和度定量关系是多孔介质多相流动系统中重要的动力学参数关系。使用设计的试验装置及试验方法测定了一维砂柱中油水两相动态流动系统的相对渗透率及饱和度数据,由试验结果分析表明:所测得的相对渗透率与实际情况吻合较好;细砂的强亲水性对不同先湿条件下的油、水相相对渗透率及饱和度有较大影响,并造成了不同先湿条件下流体间驱替机制的差异;相饱和度是影响相对渗透率的主要因素,孔隙空间中两种流体的分布方式和流体的饱和历史也影响各相相对渗透率。对试验结果用VGM模型(Parker-Lenhard模型)进行拟合所得结果较好;在水先湿条件下,将van公式拟合毛细压力-饱和度数据所得拟合参数用于VGM模型预测相对渗透率-饱和度曲线,所得结果与VGM模型直接拟合所得结果有差异,但两者所得结果均较好。

The quantified relationship between relative permeability and saturation is the key dynamic parameter relationship of multiphase flow system in porous media. Under the dynamic condition, the designed apparatus and method are employed to measure the relative permeability and saturation in water-oil two-phase system. The experiment was conducted in a one dimension sand column and the results were analyzed. It indicates that the results measured by the apparatus are in accord with those in practical condition. The fine sand is hydrophilic, which remarkably affects the relative permeability and saturation of wateroil and causes the displacement mechanism difference of different fluids in different firstly wetting conditions. The oil-water phase saturation is the main influential factor of phase relative permeability, and the viscous difference of different fluids affects the relative permeability. And the relative permeability should be determined by the liquids distribution in porous media and the saturation history of fluids. The experimental data are very well fitted in with the VGM model（or the Parker-Lenhard model）. At the same time the parameter in fitting capillary pressure-saturation data using the van formula is transferred in predicting relative permeability-saturation curve with VGM model in the water firstly wetting condition. And the result is compared with that of direct fitting of the relative permeability-saturation data by the VGM model, which suggests the latter model shows a better performance.