冷冻与常规岩心油水相对渗透率实验对比

An experimental comparison of oil-water relative permeability between frozen and conventional cores

利用室内非稳态法研究近似油藏条件下的冷冻岩心油水相对渗透率,并与常规岩心油水相对渗透率做了对比分析,结果表明:同一含水饱和度下冷冻岩心所对应的水相渗透率要高于常规岩心对应的水相渗透率,常规岩心见水时间普遍早于冷冻岩心并且含水上升较快,冷冻岩心的无水采收率和最终采收率都高于常规岩心;冷冻岩心经过洗油处理后其润湿性发生了变化,洗油时许多固体颗粒被洗出,增大了孔隙内表面积,使剩余油饱和度有所增加。建议在条件允许的范围内选用冷冻岩心测定油水相对渗透率。

A laboratory unsteady-state method wasused to research oil-water relative permeability for frozen cores under the approximate conditions of oil reservoirs, and the results were compared with those for the conventional cores. According to this comparison, if the water saturation is fixed, the water-phase permeability of frozen cores will be higher than that of conventional cores, and the conventional cores will generally be earlier in water breakthrough and faster in water-cut increase than the frozen cores, with the frozen cores being high- er in the water-free oil recovery and the ultimate oil recovery than the conventional cores. The wet- tability of frozen cores will change after oil wash- ing, and their remaining oil saturation will some- what increase due to expanding internal pore sur- face by the remove of solid particles during oil washing. So it is suggested that the frozen cores should be used to determine oil-water relative per meability in the range of allowable conditions.