An experimental study on CO2/water displacement in porous media using high-resolution Magnetic Resonance Imaging
An experimental study on CO2/water displacement in porous media using high-resolution Magnetic Resonance Imaging
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DOI：
10.1016/j.ijggc.2012.07.017
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发表时间：
2012-09
影响因子：
3.9
通讯作者：
Yongchen Song;Lanlan Jiang;Yu Liu;Mingjun Yang;Yuechao Zhao;Ningjun Zhu;Binlin Dou;A. Abudula
中科院分区：
文献类型：
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作者：
Yongchen Song;Lanlan Jiang;Yu Liu;Mingjun Yang;Yuechao Zhao;Ningjun Zhu;Binlin Dou;A. Abudula
利用高分辨率磁共振成像技术对封存条件下多孔介质中CO2/水驱替过程进行了观测。多孔介质是填充有玻璃珠的填充床。利用快速自旋回波多层成像技术（FSEM）测量了多孔介质中CO2和水的分布。对于不混溶驱替实验，从MR信号强度分布获得三个阶段。第二阶段渗透率的差异导致CO2窜流或指进现象明显。最终剩余水饱和度取决于渗透率，渗透率越低，最终饱和度越大。对于混相驱替，从磁共振信号强度分布也可将驱替过程分为三个阶段。在第一阶段，由于CO2分解为水，MR信号强度逐渐降低。在第二阶段，一个活塞状的混溶前沿从FOV（视野）的顶部均匀地移动到底部，MR信号强度急剧下降。混相驱的驱油效率大于非混相驱。很明显，水驱效率或平均CO2饱和度取决于流速。随着CO2流量的增加，CO2浓度分布相对均匀，CO2锋面也趋于均匀。此外，最终水饱和度降低。利用岩心分析方法，获得了CO2的速度，并将其用于评价毛管弥散速率、粘性主导流和重力流函数。毛细管分散率捐赠的影响，这是最大的在水饱和度为0.6和0.7。在高流速下，粘性力在多孔介质中占主导地位。在低流速时，重力变得重要，并在向下位移中起着积极的作用。
CO2/water displacement process in porous media under sequestration conditions was observed using high-resolution Magnetic Resonance Imaging (MRI) technique. The porous media was a packed bed filled with glass beads. Fast spin echo multi slice sequence (FSEM) was used to measure the distribution of CO2and water in the porous media. For immiscible displacement experiments, three stages were obtained from the MR signal intensity profile. The CO2channeling or fingering phenomena was obviously for the difference of permeability during the second stage. The final water residual saturation depended on permeability, and lower permeability always leads to larger final saturation. For miscible displacement, the displacement process was also divided into three stages from MR signal intensity profile. The MR signal intensity decreased gradually for the resolving of CO2into water in the first stage. A piston-like miscible front moved uniformly from the top to the bottom of the FOV (field of view) during the second stage, and the MR signal intensity decreased sharply. The displacement efficiency in miscible displacement is larger than that in immiscible displacement process. It is clear that water displacement efficiency or average CO2saturation depends on flow rate. With the CO2flow rate increasing, the relatively uniform CO2distribution and the uniform CO2front occurred. Additionally, final water saturation decreased. With the core analysis methods, the CO2velocities were obtained, which were applied to evaluate the capillary dispersion rate, viscous dominated fraction flow and gravity flow function. The capillary dispersion rate donated the effects of capillary, which was largest at water saturations of 0.6 and 0.7. At a high flow rate, the viscous force was dominated over the porous media. When at a low flow rate, the gravity force became important and played a positive role in downward displacements.