Adebimpe Ademola Isaac, Foroughi Sajjad, Bijeljic Branko, Blunt Martin J
Department of Earth Science and Engineering, <a href="https://ror.org/041kmwe10">Imperial College London</a>, London, SW7 2BP, United Kingdom.
Department of Chemical Engineering, <a href="https://ror.org/04snhqa82">Obafemi Awolowo University</a>, Ile-Ife, 220103, Nigeria.
Phys Rev E. 2024 Sep;110(3-2):035105. doi: 10.1103/PhysRevE.110.035105.
Conventional measurements of two-phase flow in porous media often use completely immiscible fluids, or are performed over time scales of days to weeks. If applied to the study of gas storage and recovery, these measurements do not properly account for Ostwald ripening, significantly overestimating the amount of trapping and hysteresis. When there is transport of dissolved species in the aqueous phase, local capillary equilibrium is achieved: this may take weeks to months on the centimeter-sized samples on which measurements are performed. However, in most subsurface applications where the two phases reside for many years, equilibrium can be achieved. We demonstrate that in this case, two-phase displacement in porous media needs to be modeled as percolation without trapping. A pore network model is used to quantify how to convert measurements of trapped saturation, capillary pressure and relative permeability made ignoring Ostwald ripening to account for this effect. We show that conventional measurements overestimate the amount of capillary trapping by 20-25%.
多孔介质中两相流的传统测量通常使用完全不混溶的流体，或者是在数天到数周的时间尺度上进行的。如果将这些测量应用于储气和采气研究，就无法正确考虑奥斯特瓦尔德熟化现象，从而显著高估捕集量和滞后现象。当水相中存在溶解物质的传输时，会达到局部毛细管平衡：在用于测量的厘米级样品上，这可能需要数周至数月的时间。然而，在大多数两相共存多年的地下应用中，可以实现平衡。我们证明，在这种情况下，多孔介质中的两相驱替需要建模为无捕集的渗流。使用孔隙网络模型来量化如何将忽略奥斯特瓦尔德熟化现象时测得的捕集饱和度、毛细管压力和相对渗透率的测量值进行转换，以考虑这种效应。我们表明，传统测量高估了毛细管捕集量的20% - 25%。
