Abstract: Currently, there are few studies on the multi-phase flow law of high-pour-point oil under high pressure. Focusing on the phenomena of the relative permeability curve fluctuation and wettability hysteresis in the water-flooding process of high-pour-point oil, the effect of solid particles in different periods was described microscopically; moreover, three hypotheses on wettability reversal was also proposed, including in-situ growth, water removal and oil in, and film coating. The results verified by experiments and numerical simulation indicate that the plugging and migration of solid particles at pore throat leads to the fluctuation of the displacement pressure difference and the waterflood front advance velocity, which is also the primary cause for the oscillation of relative permeability curve; the water film on the pore wall will inhibit the transformation of core surface to oil wet surface; the wax deposit thickness on the water film is smaller than that of rock wall, and the difference between them can reach 21.5%; the water film heterogeneity results in that the wax deposit thickness in the core is only 59%-77% of that of dry core (without connate water), and the transformation of core wettability to oil wet is accelerated as the water film thickness decreases; low-permeability cores are more easily affected by temperature than high-permeability cores, and the oil recovery of low-permeability cores is the lowest, which is only 23.6% of that of high-permeability cores.

Key words: high-pour-point oil, multi-phase flow law, micro flow, wettability, wax deposition

摘要： 在高压条件下对高凝油多相渗流规律的研究较少。针对高凝油水驱过程中出现的相渗曲线波动和润湿性变化滞后等现象，在微观上刻画了固相颗粒不同时期的影响，并提出了原位生长、水退油进和覆膜3种润湿性反转假说。通过实验和数值模拟进行验证的结果表明：固相颗粒在孔喉处的堵塞与运移导致了驱替压差和水驱前缘推进速度的波动变化，也是相渗曲线震荡的主要原因；孔隙壁面上的水膜会抑制岩心表面向油湿转变；水膜上的蜡沉积层厚度小于岩石壁面，且二者差值最大可达21.5%；水膜的非均质性导致岩心内蜡沉积层厚度仅为无束缚水时的59%~77%，并随水膜厚度的减小岩心润湿性向油湿转变加快；低渗岩心比高渗岩心更容易受温度的影响，低渗岩心采收率最低仅为高渗岩心的23.6%。

关键词: 高凝油, 多相渗流规律, 微观流动, 润湿性, 蜡沉积