人造岩芯孔喉结构的恒速压汞法评价

Pore-Throat Structure Evaluation of Artificial Cores with Rate-Controlled Porosimetry

利用恒速压汞实验,对3种不同工艺制作的人造岩芯孔喉特征进行研究,并与天然岩芯实验结果进行对比。3种方法制作的人造岩芯孔隙尺度分布均十分接近,且与天然岩芯数据吻合良好。人造岩芯喉道尺度分布集中,相比之下天然岩芯喉道尺度分布范围较宽,在极小的区间内也有可渗流喉道分布,同时平均喉道半径大于人造岩芯。天然岩芯可能呈现出大孔细喉的配置关系,存在更大的孔喉比,因而驱油效率更低,剩余油饱和度较人造岩芯更大。

The pore-throat structure properties of artificial cores made with three different methods are compared with the approach of rate-controlled porosimetry. The feasibility of the artificial cores to replace real cores in micro-structure experiments of reservoirs is evaluated. Pore size distribution of the artificial cores exhibits similar trait as the real core sample, while the throat size is slightly smaller, and the range is narrower compared to the real core. Meanwhile, larger pore-throat ratio may exist in real cores rather than in artificial cores, therefore the displacement efficiency of artificial cores is slightly higher and the residual oil saturation is lower than that of real cores.