Gas Injection in a Water Saturated Porous Medium: Effect of Capillarity, Buoyancy, and Viscosity Ratio
Gas Injection in a Water Saturated Porous Medium: Effect of Capillarity, Buoyancy, and Viscosity Ratio
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DOI：
10.1016/j.egypro.2013.06.475
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发表时间：
2013
期刊：
影响因子：
--
通讯作者：
T. Suekane;Katsuhiro Okada
中科院分区：
文献类型：
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作者：
T. Suekane;Katsuhiro Okada
实验研究了毛细作用和浮力对排水后非湿相饱和度的影响。利用显微层析成像技术，在孔隙尺度上显示了数值预报因子在多孔介质中的分布。粘性指进是指进过程中，粘性较小的数值预报风球取代粘性预报风球时在界面上产生的。在向上注入的情况下，与向上注入的情况相比，天然气饱和度低，因为指进被浮力增强。在向下注入的情况下，由于不利的粘度比而产生的指进被浮力抑制。因此，在较宽的毛管数范围内实现了高气体饱和度。引入邦德数和毛管数的组合无因次群来关联含气饱和度。最后，讨论了非均质性对排采后含气饱和度的影响。在平行结构的情况下，NWP流经高渗透率和低入口压力的层，特别是对于低毛管数。因此，向上和向下注入的含气饱和度都很低。在串联结构情况下，孔隙结构不连续界面处产生的毛细管入口压力对界面前孔隙结构中数值模拟饱和度的增加有很大影响。
We experimentally investigated the effect of capillarity and buoyancy on non-wetting phase (NWP) saturation after the drainage. Distributions of the NWP in porous media have been visualized by mean of microtomograhy at a pore- scale. Viscous fingering is caused on the interface when less viscous NWP is displacing viscous WP. In the case of the upward injection, gas saturation is low compared with the upward case, because the fingering is enhanced by buoyancy. In the case of the downward injection, the fingering due to unfavourable viscosity ratio is suppressed by buoyancy. As a result, the high gas saturation is achieved over the wide range of capillary number. The combined dimensionless group of Bond number and capillary number is introduced to correlate with the gas saturation. Finally, the effect of heterogeneity on gas saturation after drainage process was discussed. In the case of parallel structure, the NWP flows through layers with high permeability and with low entrance pressure especially for low capillary numbers. Therefore gas saturation is quite low both for upward and downward injections. In the case of serial structure, capillary entrance pressure caused at the interface of discontinuity of pore structure has a strong influence to increase NWP saturation in porous structure before the interface.