Abstract Carbonates can be highly heterogeneous formations with large variations in pore size distribution and pore space topology, which results in complex multiphase flow behavior. Here we investigate the spontaneous imbibition behavior of fluids in vuggy carbonates. Glass beads of 1.0 mm diameter, with dissolvable vug placeholders, are sintered to form multiple configurations of heterogeneous vuggy core with variations in matrix porosity, vug size, vug spatial location, and number of vugs. The core fabrication process is repeatable and allows the impact of vug textural properties to be investigated in a controlled manner. Capillary rise experiments are conducted in these proxy vuggy carbonate core and compared with the homogeneous non-vuggy core as reference. Continuous optical imaging is performed to track the position of the air-water interface in the cores. To understand the change in capillary height in the presence of a vug, a volume-of-fluid two-phase numerical simulation is performed in a parallel set of connected and disconnected tubes. Finally x-ray tomography scans are performed to identify the shape of the air-water interface in a select few cores. The results can be summarized as follows: disconnected vugs result in higher capillary rise compared to non-vuggy porous media. The vugs act as capillary barriers, diverting fluid flow to the adjacent connected channels, which ultimately results in a higher overall capillary rise. The results of this work highlight that radius of spontaneous invasion of aqueous phases, such as fracture fluid and hazardous wastes, are affected by vug porosity but not their distribution.

中文翻译：

---

空洞介质中的毛细管上升

摘要 碳酸盐岩是高度非均质的地层，其孔径分布和孔隙空间拓扑结构变化很大，导致复杂的多相流动行为。在这里，我们研究了空洞碳酸盐中流体的自吸行为。直径为 1.0 毫米的玻璃珠，带有可溶解的孔洞占位符，被烧结形成多种结构的异质孔洞核心，其基质孔隙率、孔洞大小、孔洞空间位置和孔洞数量各不相同。核心制造过程是可重复的，并允许以受控方式研究孔纹理特性的影响。在这些代理孔洞碳酸盐岩心中进行了毛细管上升实验，并与作为参考的均质非孔洞岩心进行了比较。执行连续光学成像以跟踪岩心中气水界面的位置。为了了解存在孔洞时毛细管高度的变化，在一组平行的连接和断开的管中进行了流体体积两相数值模拟。最后，执行 X 射线断层扫描以识别选定的几个岩心中空气-水界面的形状。结果可以总结如下：与非孔洞多孔介质相比，不连贯的孔洞导致更高的毛细管上升。这些孔洞充当毛细管屏障，将流体流转移到相邻的连接通道，最终导致更高的整体毛细管上升。这项工作的结果强调了水相的自发侵入半径，例如压裂液和危险废物，