We use fast synchrotron X‐ray microtomography to understand three‐phase flow in mixed‐wet porous media to design either enhanced permeability or capillary trapping. The dynamics of these phenomena are of key importance in subsurface hydrology, carbon dioxide storage, oil recovery, food and drug manufacturing, and chemical reactors. We study the dynamics of a water‐gas‐water injection sequence in a mixed‐wet carbonate rock. During the initial waterflooding, water displaced oil from pores of all size, indicating a mixed‐wet system with local contact angles both above and below 90°. When gas was injected, gas displaced oil preferentially with negligible displacement of water. This behavior is explained in terms of the gas pressure needed for invasion. Overall, gas behaved as the most nonwetting phase with oil as the most wetting phase; however, pores of all size were occupied by oil, water, and gas, as a signature of mixed‐wet media. Thick oil wetting layers were observed, which increased oil connectivity and facilitated its flow during gas injection. A chase waterflooding resulted in additional oil flow, while gas was trapped by oil and water. Furthermore, we quantified the evolution of the surface areas and both Gaussian and the total curvature, from which capillary pressure could be estimated. These quantities are related to the Minkowski functionals which quantify the degree of connectivity and trapping. The combination of water and gas injection, under mixed‐wet immiscible conditions, leads to both favorable oil flow and significant trapping of gas, which is advantageous for storage applications.

中文翻译：

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同步加速器成像在混合湿多孔介质中的三相流原位表征

我们使用快速同步加速器X射线断层扫描来了解混合湿多孔介质中的三相流，以设计增强的渗透性或毛细管捕集。这些现象的动力学在地下水文学，二氧化碳存储，石油采收，食品和药物制造以及化学反应器中至关重要。我们研究了混合湿碳酸盐岩中水-气-水注入序列的动力学。在最初的注水过程中，水从各种尺寸的孔中驱出，表明混合湿系统的局部接触角均大于或小于90°。当注入气体时，气体置换的油优先具有微不足道的水置换。用入侵所需的气压来解释这种行为。总的来说，天然气是最不润湿的阶段，石油是最润湿的阶段。但是，各种大小的孔都被油，水和气占据，这是混合湿介质的标志。观察到了较厚的油润湿层，这增加了油的连通性并在注气期间促进了油的流动。追水驱使油流增加，而天然气则被油和水捕获。此外，我们量化了表面积的变化以及高斯和总曲率的变化，从中可以估计毛细压力。这些数量与Minkowski功能有关，后者可量化连接和捕获的程度。