Estaillades Carbonate

The effect of pore-scale heterogeneity on non-Darcy flow behaviour is investigated by means of direct flow simulations on 3-D images of Estaillades carbonate. The critical Reynolds number indicating the cessation of the creeping Darcy flow regime in Estaillades carbonate is two orders of magnitude smaller than in Bentheimer sandstone, and is three orders of magnitude smaller than in the beadpack. It is inferred from the examination of flow field features that the emergence of steady eddies in pore space of Estaillades at elevated fluid velocities accounts for the early transition away from the Darcy flow regime.本研究通过对埃斯塔亚德碳酸盐岩（Estaillades carbonate）的三维图像开展直接流动模拟，探究了孔隙尺度非均质性对非达西流动特性的影响。研究结果显示，表征埃斯塔亚德碳酸盐岩中蠕变达西流态终止的临界雷诺数，较本特海姆砂岩（Bentheimer sandstone）小两个数量级，较珠充填体（beadpack）小三个数量级。通过对流场特征的分析可知，当流体流速升高时，埃斯塔亚德碳酸盐岩孔隙空间内出现的稳定涡旋，是其较早脱离达西流态的核心成因。