Abstract During processes such as solvent-steam co-injection and tertiary CO2 flooding, oil may be prevented from direct contact with solvent by a water barrier which greatly affects microscopic displacement efficiency. As a result of diffusion through the water barrier, both oil and water phases swell progressively. If oil swelling displaces the blocking water completely, direct contact between solvent and oil can be achieved which results in high oil recovery. In this study, a moving mesh technique is applied to simulate swelling of a trapped oil blob by CO2 diffusion through a blocking water at pore scale. A moving interface between oil and water is considered to track the swelling process. The modeling results were validated with micromodel experiments on the recovery process of water-shielded oil in a dead-end pore. The water film rupture time for typical oil and water thicknesses (in micro scale) was calculated using experimental data for oil-water-CO2 system. Finally, a dimensionless rupture time was introduced and it was used to predict trapped oil recovery as a function of contact time for various pore body and throat size distributions. The results can be used to estimate the time scales necessary for having maximum trapped oil recovery.

中文翻译：

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使用移动网格技术模拟 CO 2 扩散到孔隙尺度的水屏蔽油中

摘要 在溶剂-蒸汽共注和三次CO2驱等过程中，可以通过水屏障阻止石油与溶剂直接接触，这对微观驱替效率有很大影响。作为通过水屏障扩散的结果，油相和水相都逐渐膨胀。如果油溶胀完全取代堵塞水，则可以实现溶剂与油的直接接触，从而实现高采收率。在这项研究中，应用移动网格技术来模拟 CO2 扩散通过孔隙尺度的阻塞水导致被困油团膨胀。油和水之间的移动界面被认为是跟踪膨胀过程。建模结果通过闭塞孔隙中水保护油采收过程的微观模型实验进行验证。使用油-水-CO2 系统的实验数据计算典型油和水厚度（微尺度）的水膜破裂时间。最后，引入了无量纲破裂时间，并将其用于预测作为各种孔体和喉道尺寸分布的接触时间的函数的圈闭油采收率。结果可用于估计获得最大捕集油采收率所需的时间尺度。