Mechanisms of acoustic stimulation of fluid flow in porous media: Integration of laboratory pore-scale studies and theoretical model development

两个普遍存在的实际问题与多孔介质中有机流体的流动性降低有关：难以从地下水中去除有机污染物和从储层中不完全回收石油。 现有的解决方案是昂贵的，而且往往对生态有害。 另一方面，孔隙流体的流动可以通过应用弹性波而显著增强。 声波刺激是生态清洁和经济的。 由于对弹性波调动孔隙流体的机理认识不足，阻碍了声波增产技术的推广。 声波刺激理论实际上并不存在。 爱荷华州州立大学的提议团队旨在深入了解刺激的定量物理机制并建立关键现象的数学模型。为了研究流体-声音相互作用的微观机制，研究人员将使用化学工程系开发的孔隙尺度流动可视化装置。 该单元匹配多孔单元中所有相的折射率，使其对光透明。 将荧光染料添加到有机流体中，使其在激光光源照射下成为唯一可见的流体;通过数码相机捕获二维图像，然后将其组合在系统的三维渲染中。 该装置允许直接观察有机神经节在声波作用下的运动。 这些调查将与地质和大气科学系开发声波刺激的理论和数值模型相结合。 包括蠕动运动、机械振动对毛细作用力的影响、神经节的聚结和边界膜效应。 理论分析将采用多相连续介质方法（Navier-Stokes方程）和蒙特-卡罗（孔隙网络）模拟，通过将理论发展与孔隙尺度研究相结合，建立声波激励的工作模型。 该模型将为新技术在环境恢复和提高石油采收率方面的应用奠定基础。

O125214BeresnevTwo pervasive practical problems are related to the reduced mobility of organic fluids in porous media: the difficulty in removing organic contaminants from groundwater and incomplete petroleum recovery from reservoirs. The existing solutions are expensive and often ecologically hazardous. On the other hand, the flow of pore fluids can be significantly enhanced by the application of elastic waves. The sonic stimulation is ecologically clean and economical. The proliferation of sonic-stimulation technologies has been hampered by inadequate understanding of the mechanisms by which the elastic waves mobilize pore fluids . A theory of sonic stimulation virtually does not exist. The proposing team at Iowa State University aims at gaining insight into quantitative physical mechanisms of stimulation and building a mathematical model of key phenomena in play.To study the microscopic mechanisms of fluid-sound interaction, the investigators will use the pore-scale flow visualization apparatus developed at the Department of Chemical Engineering. The unit matches the refractive index of all phases in a porous cell to make it transparent to light. A fluorescent dye is added to the organic fluid to make it the only one visible when illuminated by a laser source; the two-dimensional images are captured by a digital camera and then combined in a three-dimensional rendering of the system. The unit allows direct observation of the movement of organic ganglia subjected to sonic forcing. These investigations will be combined with the development of a theoretical and numerical model of sonic stimulation at the Department of Geological and Atmospheric Sciences. Among the mechanisms to include is the peristaltic motion, the effects of mechanical vibrations on capillary forces, coalescence of ganglia, and the boundary-film effects. The theoretical analyses will use the multi-phase continuum approach (Navier-Stokes equations) and the Monte-Carlo (pore-network) simulations.By integrating the theory development with the pore-scale investigations, a working model of the sonic stimulation will be built. This model will serve the basis for the applications of the new technology to environmental restoration and enhanced oil recovery.