Geometry & Dynamics of Interfaces in Porous Media

多孔介质中界面的几何和动力学。普渡大学这个奖项是根据2009年美国复苏和再投资法案(公法111-5)资助的。多相流体在多孔介质中的流动问题在许多领域都很重要，包括地下水修复、从地下储集层中提取石油和天然气以及地质地层中的碳封存。多流体在多孔系统中行为的实验和理论理解的发展是一个活跃的研究领域，有许多悬而未决的问题。众所周知，毛细压力(Pc)和饱和度(Sw)的测量不足以完全描述流体分布的行为。最近的工作表明，流体相之间的单位体积的界面面积(On)是描述这些体系所必需的第三个“状态变量”。虽然平衡条件下的二维微观模型的研究为界面几何在多相体系中的作用提供了重要的定量见解，但关键问题仍有待解决。拟议研究的科学目标包括：(1)确定在2-D系统中观察到的Pc-Sw-On关系是否以及如何转换到3-D系统。我们将利用共聚焦激光扫描显微镜制作3D透明微观模型，用于直接成像3D中的流体分布。将努力开发三维透明微观模型，从中提取流体-流体和流体-固体界面的信息，以确定微观模型维度对Pc-Sw-awn关系的影响。(2)确定薄膜在Pc和界面几何形状上的作用。我们将1)使用激光共聚焦显微镜对薄膜、薄膜口袋和三维流体界面进行成像，特别是夹带润湿相和相关薄膜的存在和运动；以及(2)在二维微观模型中制造微型电容传感器，以直接测量薄膜厚度。将做出重大努力来证明微型电容器用于测量微型模型中的局部压力的用法、分辨率和重复性。(3)确定动态条件下的松弛行为是取决于界面几何形状随时间的演变，还是仅仅是介质的孔隙几何性质。虽然了解平衡条件下的流体分布很重要，但许多工业和自然系统都会经历压力瞬变。我们将使用高帧频成像来研究二维微观模型中流体界面在压力瞬变后接近平衡时的动态行为。

Geometry and Dynamics of Interfaces in Porous MediaL. J. Pyrak-Nolte & N. J. GiordanoPurdue UniversityThis award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5). The problem of multiphase fluid flow in porous media is important in many areas, including ground water remediation, the extraction of oil & gas from subsurface reservoirs and carbon sequestration in geologic formations. The development of experimental and theoretical understandings of the behavior of multiple fluids in porous systems is an active area of research with many open questions. It is known that measurements of capillary pressure (Pc) and saturation (Sw) are not sufficient to fully describe the behavior of fluid distributions. Recent work has suggested that the interfacial area per volume between the fluid phases (awn) is an essential third "state variable" needed for a description of these systems. While studies of 2-D micro-models under equilibrium conditions has provided important quantitative insight into the role of interfacial geometry in multiphase systems, key issues remain to be resolved. Scientific objectives of the proposed research include: (1) Determine if and how the Pc-Sw-awn relationship observed in 2-D systems translates to 3-D systems. We will fabricate 3-D transparent micro-models for direct imaging of fluid distributions in 3-D using confocal laser scanning microscopy. A significant effort will be made to develop 3-D transparent micro-models from which information can be extracted on fluid-fluid and fluid-solid interfaces to determine the effect of micro-model dimensionality on the Pc-Sw-awn relationship. (2) Determine the role of thin films on Pc and on the interfacial geometry. We will 1) use laser confocal microscopy to image films, film pockets and three dimensional fluid interfaces-especially the presence and movement of entrained wetting phase and associated films; and (2) fabricate micro-capacitor sensors inside the 2-D micro-models to measure film thickness directly. A significant effort will be made to demonstrate the use, resolution and repeatability of micro-capacitors for measuring local pressures in the micro-model. (3) Determine if relaxation behavior under dynamic conditions depends on the evolution of the interfacial geometry with time, or if it is only a property of the pore geometry of the medium. While understanding fluid distributions under equilibrium conditions is important, many industrial and natural systems experience pressure transients. We will use high frame rate imaging to study the dynamic behavior of fluid interfaces in 2-D micro-models as they approach equilibrium after a pressure transient.