标题： 三级EOR类似微流体实验：粘度比对油团迁移的影响 显示英文标题

标题： Tertiary EOR-like microfluidic experiments: influence of viscosity ratio on oil clusters mobilization

摘要： 理解不混相两相流在多孔介质中的孔隙尺度动力学对于优化提高采收率策略至关重要。在本研究中，我们通过微流体装置研究了油团的运移动力学，该装置允许在水湿芯片中对流动进行孔隙尺度的直接表征。我们在水驱期间改变了流速，并通过在水驱期后注入不同组成的甘油/水混合物来改变粘度比。在水驱过程中，流速对残余油的影响有限。在随后注入甘油/水混合物后，油的采收率显著提高。为了更好地理解采收机制，将油团分为液滴、块状物和簇状物。增加注入混合物的粘度仅导致簇状物数量略有减少，但显著降低了它们的总体积，从而减少了整体油饱和度。这是由于簇状物破裂成较小的簇状物、块状物和液滴，这些随后被运移并离开，而原始簇状物的剩余部分仍然被捕获。只要考虑液滴和块状物，它们的数量似乎仅弱变化，甚至它们的数量可能暂时增加，因为它们来源于簇状物的破裂。因此，该过程可以分为两个主要步骤：簇状物破裂向介质中提供块状物和液滴，以及第二步，这些移动的油实体被运移。认为油运移的特征时间比簇状物破裂所需的时间更长。 显示英文摘要

摘要： Understanding the pore-scale dynamics of immiscible two-phase flow in porous media is crucial 9 for optimizing EOR strategies. In this work, we investigate the mobilization dynamics of oil clusters by 10 means of microfluidic devices that allow pore scale direct characterization of flow in water-wet chips. We varied both flow rates during waterflooding and the viscosity ratio by injecting Glycerol/water mixtures of various compositions right after the waterflooding period. During waterflooding, the flow rate has only a limited impact on residual oil. With a subsequent injection of a Glycerol/water mixture, the oil recovery is significantly enhanced. To better understand the recovery mechanisms, oil clusters were categorized into droplets, blobs and ganglia. Increasing the viscosity of the injected mixture resulted in only a slight reduction in the number of ganglia but significantly decreased their total volume, thus reducing overall oil saturation. This is due to ganglia breakup into smaller ganglia, blobs and droplets that are subsequently mobilized and transported away, while remaining parts of original ganglia still remain trapped. As long as droplets and blobs are considered, their number is seen to only weakly change by the increase of mixture viscosity and even their number may temporarily increase as they result from ganglia rupture. So, the process can be separated in two main steps: ganglia breakage that feed the medium in blobs and droplets and a second step where such moving oil entities are transported. The characteristic time for oil transport is believed to be longer than that required for ganglia breakage.