Journal of Colloid and Interface Science ( IF 9.4 ) Pub Date : 2023-05-25 , DOI: 10.1016/j.jcis.2023.05.070 Deepak Singh 1 , Helmer André Friis 1 , Espen Jettestuen 2 , Johan Olav Helland 3
Hypothesis
Ostwald ripening of gas bubbles is a spontaneous mass transfer process that can impact the storage volume of trapped gas in the subsurface. In homogeneous porous media with identical pores, bubbles evolve toward an equilibrium state of equal pressure and volume. How the presence of two liquids impacts ripening of a bubble population is less known. We hypothesize that the equilibrium bubble sizes depend on the surrounding liquid configuration and oil/water capillary pressure.
Method and numerical experiments
We investigate ripening of nitrogen bubbles in homogeneous porous media containing decane and water using a level set method that alternately simulates capillary-controlled displacement and mass transfer between bubbles to eradicate chemical-potential differences. We explore impacts of initial fluid distribution and oil/water capillary pressure on the bubble evolution.
Findings
Ripening in three-phase scenarios in porous media stabilizes gas bubbles to sizes that depend on their surrounding liquids. Bubbles in oil decrease in size while bubbles in water increase in size with increasing oil/water capillary pressure. Bubbles in oil reach local equilibrium before the three-phase system stabilizes globally. A potential implication for field-scale gas storage is that the trapped gas fractions in oil and water vary with depth in the oil/water transition zone.
中文翻译:
多孔介质中存在油和水时气泡的孔隙级 Ostwald 熟化
假设
气泡的奥斯特瓦尔德成熟是一种自发的传质过程,可以影响地下捕获气体的储存量。在具有相同孔隙的均质多孔介质中,气泡向压力和体积相等的平衡状态演化。两种液体的存在如何影响气泡种群的成熟还鲜为人知。我们假设平衡气泡大小取决于周围的液体配置和油/水毛细管压力。
方法与数值实验
我们使用水平集方法研究了含有癸烷和水的均质多孔介质中氮气气泡的成熟,该方法交替模拟毛细管控制的位移和气泡之间的质量传递以消除化学势差。我们探讨了初始流体分布和油/水毛细管压力对气泡演化的影响。
发现
在多孔介质中的三相场景中成熟可将气泡稳定到取决于其周围液体的大小。随着油/水毛细管压力的增加,油中气泡的尺寸减小,而水中气泡的尺寸增加。在三相系统整体稳定之前,油中的气泡达到局部平衡。对油田规模储气库的潜在影响是油和水中的捕获气体分数随油/水过渡带的深度而变化。