油水两相渗流对称性特征研究与应用

Study and Application of the Symmetry Feature of Oil-Water Seepage Flow

通过岩心相渗资料分析,发现在一定条件下,油水相对渗透率比值随归一化饱和度变化呈现对称性.针对这一现象,结合实际岩心驱替和数字岩心的实验结果,考虑水驱油过程中的优势相和弱势相的转换,构建了新的油水渗流关系,即油、水相对渗透率比与归一化弱势相饱和度的幂指函数关系.设计了不同条件下水驱油实验,探讨了水驱油时对称性特征产生条件,并分析了其对水驱特征曲线的影响.最后利用对应条件下的油藏实际数据,验证了对称性的存在及双对数水驱特征曲线的适应性.表明考虑弱势相转换的幂指关系较好的表征了凹型水驱特征全生命周期的变化,丰富了油水两相渗流基础理论,对水驱特征曲线的研究和应用具有一定借鉴意义.

On the basis of relative permeability curves,it was discovered that the symmetrical characteristic exists between the oil-water relative permeability ratio and normalized saturation.Contraposing to this phenomenon,through the experimental results of core displacement and digital core simulation,a new model about kro/krw and sw,considering on the transition between advantage phase and disadvantage phase among the process of percolation,was deducted creatively.The symmetry feature was discussed on the process of displacement designed specially,as well as the conditions for symmetry generation.Finally,it was proved to be correct and reasonable by the practical production data.Conversion from advantage phase to disadvantage phase,which was considered in the new model,was more compatible in the whole life cycle of concave shape water flooding process.The conclusion above enriched the theoretical basis,and has reference meaning in the research of water flooding curves.