Miah Md Abdul Karim, Ahasan Kawkab, Kingston Todd A, Olsen Michael G, Juárez Jaime J
Department of Mechanical Engineering, Iowa State University, Ames, Iowa 50011, United States.
ACS Omega. 2024 Jul 24;9(31):34070-34080. doi: 10.1021/acsomega.4c04680. eCollection 2024 Aug 6.
Pore-scale oil displacement behavior was investigated in a porous media micromodel using microscopic particle image velocimetry (μPIV). Porous media micromodels consisting of an ordered square array of cylindrical pillars with 50 and 70% porosities were fabricated with photolithography. The oil displacement was performed with the injection of water at flow rates of 37.5, 75, and 150 μL/h. These flow rates correspond to Reynolds number of 1.1 × 10, 2.2 × 10, and 4.4 × 10, respectively in the 50% porous channel, and 1.84 × 10, 3.69 × 10, and 7.38 × 10, respectively in the 70% porous channel. The capillary numbers for these flow rates are 2.18 × 10, 4.36 × 10, and 8.72 × 10, respectively in the 50% porous channel, and 1.56 × 10, 3.12 × 10, and 6.23 × 10, respectively in the 70% porous channel. The micromodel is initially saturated with oil, with the invading water phase following the path of least resistance as it displaces the oil. The μPIV data were used to construct probability density functions (PDFs) which show an initial, nonzero, peak in transverse velocity as the water enters the micromodel. The PDFs broaden with time, indicating that the water is spreading, before retracting to a peak velocity of 0 mm/s, indicating that the water displacement has achieved equilibrium. We developed a model based on conservation of mass to describe the efficiency of the displacement process. All flow conditions demonstrate peak displacement efficiency when the amount of oil phase displacement is ∼9 pore volumes in 50% porous channel and ∼4 pore volumes in 70% porous channel.
利用微观粒子图像测速技术（μPIV）在多孔介质微观模型中研究了孔隙尺度下的驱油行为。采用光刻技术制作了由孔隙率分别为50%和70%的圆柱形支柱有序方形阵列组成的多孔介质微观模型。以37.5、75和150 μL/h的流速注入水进行驱油实验。这些流速在50%孔隙率的通道中分别对应雷诺数为1.1×10、2.2×10和4.4×10，在70%孔隙率的通道中分别对应雷诺数为1.84×10、3.69×10和7.38×10。这些流速下的毛细管数在50%孔隙率的通道中分别为2.18×10、4.36×10和8.72×10，在70%孔隙率的通道中分别为1.56×10、3.12×10和6.23×10。微观模型最初充满油，侵入的水相在驱替油时遵循阻力最小的路径。μPIV数据用于构建概率密度函数（PDFs），该函数显示当水进入微观模型时横向速度有一个初始的非零峰值。PDFs随时间变宽，表明水在扩散，然后收缩到0 mm/s的峰值速度，表明水驱替已达到平衡。我们基于质量守恒开发了一个模型来描述驱替过程的效率。所有流动条件下，当油相驱替量在50%孔隙率的通道中约为9个孔隙体积、在70%孔隙率的通道中约为4个孔隙体积时，均表现出峰值驱替效率。
