多孔介质中蜡沉积规律的实验研究

多孔介质的本身及原油流动特征的复杂性,决定了研究含蜡原油在多孔介质中的蜡沉积规律的困难性。与地面管流状态下蜡沉积规律的实验方法不同,从满足油藏应用出发,结合油层物理理论,提出了等效毛细管的概念,利用天然岩心的油-油驱替实验结果,计算得到高含蜡原油在多孔介质中蜡沉积量、沉积速度等相关参数,实现了多孔介质中的蜡沉积规律的定量化表征。结果表明多孔介质中的蜡沉积量与岩心渗透率的降低比存在较好的线性关系,且随着原油注入PV数的增加,蜡的累计沉积量逐渐趋于稳定。而温度越低,蜡的沉积速度越快,对储层的伤害出现的时间越早,最终的损害程度也最大。

The experimental research on wax deposition in natural porous media

The method of study the wax deposition in natural porous media is more difficulty than that in ground pipe, since the complexity of porous media and the flow characteristics of waxy crude are different between the porous media and ground pipe. In this paper, firstly the concept of equivalent capillary was created in terms of reservoir physics, and then the volume of wax deposition was calculated based on the reduction ratio of permeability during the oil flooding. The result illustrated that the amount of wax deposition and core permeability in porous media showed a good linear relationship, the cumulative amount of wax deposition tends to be a constant with the increase of PV injection of crude. The lower the temperature of crude was, the wax deposition rate was faster, and the reservoir damage occurred earlier, the ultimate damage was the largest. The result in this paper can be used to provide some parameters on wax deposition in porous media in the field of reservoir engineering.