Hydraulic Tomography in Highly Heterogeneous Geologic Media: Field and Computational Investigations

有关地下水力参数的信息对于彻底了解流体流动和污染物传输过程至关重要。对这些过程的详细了解对于评估地下水供应、地下水修复、开采化石燃料、评估核废料处置场和就地浸出金属等是必要的。然而，地下在多个尺度上是不均匀的，这大大增加了我们对这些过程的理解。 水力层析成像(HT)是近年来迅速发展起来的一种研究地下水力传导性(K)和比容(SS)非均质性的新方法。与地球物理层析成像不同的是，前者依靠抽水或注水作为激励源，而后者依靠电磁信号作为激励源。虽然HT已被证明是一种很有前途的地下非均质性成像方法，但迫切需要检查：1)其他现场数据是否可以改善HT结果；2)HT是否可以在更大范围内有效；以及3)HT在裂隙岩石地形中是否有效。因此，我们将首先研究将其他现场数据(例如地质、地球物理和化探)与抽水试验数据融合在高温测试结果上的有效性。下一步，这个项目将研究在比先前尝试的更大的规模(100‘S到1000’S米)进行HT调查的可行性。最后，本项目还将检验高温对裂隙岩石的适用性。总而言之，这些研究项目将有助于确定高温技术是否能够显著改善与各种行业(水、修复、能源、采矿等)所需的分辨率和规模相关的地下表征工作。 拟议的研究重点是进行互补性的现场和计算调查，这将显著提高我们绘制多孔和裂隙地质介质中地下非均质性的能力。这种能力的发展还将使我们能够显著提高我们对高度不均匀地质介质中的流体流动和污染物传输过程的基本理解。

Information about subsurface hydraulic parameters is critical for thorough understanding of fluid flow and contaminant transport processes. A detailed understanding of these processes is necessary for the evaluation of groundwater supplies, groundwater remediation, extraction of fossil fuels, evaluation of nuclear waste disposal sites, and in situ leaching of metals, etc. However, the subsurface is heterogeneous at multiple scales and this significantly complicates our understanding of these processes. Hydraulic tomography (HT) is rapidly emerging as a new method to image the subsurface heterogeneity of both hydraulic conductivity (K) and specific storage (Ss). HT is different from geophysical tomography, as the former relies on pumping or injection of water as a source of excitation, while the latter relies on electromagnetic signals as sources. While HT has been shown to be a promising method for imaging subsurface heterogeneity, there is a critical need to examine whether: 1) other site data can improve HT results; 2) HT can be effective at larger scales; and 3) HT is effective in fractured rock terrains. Therefore, we will first examine the effectiveness of fusing other site data (e.g., geological, geophysical and geochemical) with pumping test data on HT results. Next, this project will examine the feasibility of conducting HT surveys at a considerably larger scale (100's to 1000's m) than previously attempted. Lastly, this project will also examine the applicability of HT to fractured rocks. Collectively, these research projects will help determine whether HT can significantly improve subsurface characterization efforts relevant at the resolution and scale necessary for various industries (water, remediation, energy, mining, etc.). The proposed research focuses on conducting complementary field and computational investigations that should significantly advance our capabilities to map subsurface heterogeneity in porous and fractured geologic media. Development of such capabilities will also allow us to significantly advance our fundamental understanding of fluid flow and contaminant transport processes in highly heterogeneous geologic media.