Collaborative Research: Hydrogeophysical Quantification of Hydraulic Conductivity from Electrical Measurements of the Effective Properties of Porous Media

我们将进行从复电导率（sigma*）测量中量化水力传导率（K）的研究。我们将研究（1）博伊西水文地球物理研究站（BHRS）的粗冲积层，以及（2）较细的冰川融化层。（sigma*）包含关于（a）互连孔体积、（B）互连孔表面积和（c）控制流量的孔喉尺寸的信息。我们将探讨低频电参数是否可以提供代理这些孔隙几何参数用于K预测的基础上渗流理论，以及毛细管模型。具有窄粒度分布的土壤在理论上与孔隙长度尺度相关的极化中表现出低频峰。基于渗流理论的K预测模型利用特征长度尺度。我们的工作将探索K预测的有效性的基础上，使用（西格玛 *）测量给出的孔隙长度尺度的渗流型理论。表现出宽粒度分布的土壤通常没有极化峰，而是在（sigma*）测量的频率范围内表现出恒定的极化。基于毛细管模型的K预测模型依赖于管的水力半径的替代测量，通常是每单位孔隙体积的可测量比表面积（Spor）。我们的研究将探讨极化的幅度是否也可以用于开发K预测的电气模型。实验室研究将检查候选岩石物理关系连接（sigma*）的有效孔隙半径和（Spor）的措施。我们将检查（1）（r-）孔半径关系，其中（r）是与（σ *（w））极化的频率（w）中的峰值相关的弛豫时间，以及（2）单频（σ ′）-（Spor）关系。一个理论框架的解释（sigma*（w））在复杂的表面电导率（（sigma*）surf（w）），将推导出其预测能力的评价与达西流测试比较。将在BHRS检查升级。基于钻孔（sigma*）剖面的水力传导率估计值将与多级段塞试验的K估计值进行比较。用于反演（sigma*）数据集以进行K的层析成像估计的两种策略是：（1）假设固定K预测方程，将（sigma*）图像直接转换为K图像，以及（2）结构反演，由此估计K分带。这些策略将通过与基于钻孔K测量的克里金法估计的BHRS处的空间K分布以及可用的水力层析成像仪进行比较来评估。学生在这个项目的第三年。我们还将在罗格斯-纽瓦克（R-N）校区开发水文物理学的荣誉学生本科生（HUG）研究经验。这一举措，与R-N荣誉学院合作运行，每学期将提供2-3个HUG津贴。我们将有选择地针对R-N校园独特的少数民族人口。我们还将加快正在进行的努力，使BHRS成为水文物理学的试验台。为进行这项研究而购买的设备将通过水文测量设施（HMF）-水文科学促进大学联盟（CUAHSI）的地球物理模块提供给水文界。

We will conduct research on quantification of hydraulic conductivity (K) from complex conductivity (sigma*) measurements. We will study (1) coarse alluvial deposits of the Boise Hydrogeophysical Research Site (BHRS), and (2) finer glacial melt deposits. The (sigma*) contains information on (a) the interconnected pore volume, (b) the interconnected pore surface area, and (c) the pore throat size controlling flow. We will explore whether low frequency electrical parameters can provide proxies of these pore geometrical parameters used in K prediction based on percolation theory, as well as capillary tube models. Soils with a narrow grain size distribution exhibit a low-frequency peak in polarization theoretically related to a pore length scale. Models for K prediction based on percolation theory utilize a characteristic length scale. Our work will explore the effectiveness of K prediction based on percolation type theory using the pore length scale given by (sigma*) measurements. Soils that exhibit a broad grain size distribution are typically devoid of a polarization peak and instead exhibit a constant polarization over the frequency range of (sigma*) measurements. Models for K prediction based on capillary tube models rely on a proxy measure of the hydraulic radius of tubes, usually the measurable specific surface area per unit pore volume (Spor). Our research will explore whether the magnitude of the polarization can also be used to develop electrical models of K prediction.Laboratory studies will examine candidate petrophysical relationships linking (sigma*) to measures of the effective pore radius and (Spor). We will examine (1) the (r-) pore radius relation, where (r) is a relaxation time related to the peak in frequency (w) of the (sigma*(w)) polarization, and (2) the single frequency (sigma')-(Spor) relation. A theoretical framework for interpretation of (sigma*(w)) in terms of a complex surface conductivity ((sigma*)surf(w)), will be derived and its predictive capability evaluated by comparison with Darcy flow tests. Upscaling will be examined at the BHRS. Hydraulic conductivity estimates based on borehole (sigma*) profiles will be compared with K estimates from multi-level slug tests. Two strategies for inverting (sigma*) datasets for tomographic estimates of K are: (1) direct conversion of (sigma*) images to K images assuming a stationary K prediction equation, and (2) a structural inversion whereby the K zonation is estimated. These strategies will be assessed via comparison with spatial K distribution at the BHRS estimated from kriging of borehole-based K measurements, and available hydraulic tomography datasets.A Hydrogeophysics Workshop will be offered to Ph.D. students during Yr 3 of this project. We will also develop Honors student UnderGraduate (HUG) research experiences in Hydrogeophysics on the Rutgers-Newark (R-N) campus. This initiative, run in collaboration with the R-N Honors College, will provide 2-3 HUG stipends per semester. We will selectively target the unique minority population of the R-N campus. We will also accelerate ongoing efforts to make the BHRS a test bed for hydrogeophysics. Equipment purchased to conduct this research will be made available to the hydrological community via the Hydrologic Measurement Facility (HMF)-Geophysics module of the Consortium of Universities for the Advancement of Hydrologic Science (CUAHSI).