A Unified Approach to Characterizing Fracture-Flow Systems: Coupling Radar Tomography, Tracer Experiments, and Hydraulic Data

小行星9705812 水文地质学中最紧迫的问题之一是描述围岩系统的非均匀性。 水力特性控制裂缝流动的准确的三维表征是水力水头变化和溶质运移的预测模型所必需的。 这个问题一直很困难，因为通常单一类型的数据（例如，水力试验）已被用于推导裂缝流动路径和流动障碍的复杂模式。 对数据集的单独分析可能导致破裂岩石几何形状和水力性质的“地图”彼此不一致。 我们建议，同时反演多种类型的信息，从地球物理数据（本地和跨井雷达）的水力测试，示踪剂测试提供了一种方法，可以确定地下岩石含水层的非均质性，包括断裂带的几何形状，连通性和传输特性。 每种类型的数据进行了分析与适当的物理模拟模型，包括波的传播，水头变化，溶质迁移。 我们提出了一个耦合反演过程的基础上，一个非常灵活的优化过程称为模拟退火。 该方法将产生与所有类型的数据（例如，水头、浓度、雷达），并指出了复盖区几何形状、水力传导率估计值和空间变量不确定性估计值。 它将被开发并应用于合成和现场数据。 我们过去对沉积矿床的经验表明，综合数据分析练习可以促进“耦合”反演方法的快速开发和测试。 一旦所提出的方法的优点和局限性被理解，应用到复杂的现场数据提供了一个真正的测试方法。 现场数据将来自新罕布什尔州镜湖的岩石实验场。 到目前为止，美国地质勘探局已经收集了雷达层析成像、地震层析成像、钻孔地球物理测井、水力测试数据和示踪剂测试数据。 在我们认为是一个独特的机会，他们愿意提供这些新收集的数据给我们。 该项目将深入了解可以从不同类型的数据中提取的信息，数据的相对价值，以及如何使用不同类型的数据的联合分析来推导出可重构区域架构。

9705812 Gorelick Among the most pressing problems in hydrogeology is describing heterogeneity in fractured-rock systems. Accurate 3D characterization of the hydraulic properties controlling fracture flow is required for predictive models of hydraulic head changes and solute migration. The problem has been difficult because typically a single type of data (e.g., hydraulic tests) has been used to deduce the complex pattern of fracture flow paths and flow barriers. Individual analysis of data set may lead to "maps" of fractured rock geometry and hydraulic properties that are inconsistent with each other. We suggest that simultaneous inversion of multiple types of information ranging from geophysical data (local and cross well radar) to hydraulic tests to tracer tests provides an approach that can identify fractured-rock aquifer heterogeneities including fracture zone geometry, connectivity, and transmissive properties. Each type of data is analyzed with the appropriate physical simulation models, including ones for wave propagation, hydraulic head changes, and solute migration. We propose a coupled-inversion process based on a very flexible optimization procedure known as simulated annealing. The method will yield images that are consistent with all the types of data (e.g., heads, concentrations, radar) and indicate fracture-zone geometry, hydraulic conductivity estimates, and spatially variable uncertainty estimates. It will be developed and applied to both synthetic and field data. Our past experience for sedimentary deposits has shown that synthetic data analysis exercises can promotes rapid development and testing of the "coupled" inversion approach. Once the benefits and limitations of the proposed method are understood, application to complex field data provides a true test of the method. The field data will be from the fractured-rock experimental site at Mirror Lake, New Hampshire. To date, the USGS has collected radar tomography, seismic tomography, borehole geophysical log s, hydraulic test data and tracer test data. In what we consider to be a unique opportunity, they are willing to make these newly collected data available to us. The project will provide insight into the information that can be extracted from different types of data, the relative worth of data, and how joint analysis of different types of data can be used to deduce fracture-zone architecture.