Remote monitoring of subsurface fluid flow

远程监测地下流体流动

• 批准号: RGPIN-2020-06569
• 负责人: Butler, Karl
• 金额: $ 2.19万
• 依托单位: University of New Brunswick
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=751124
• 关键词: Remote; monitoring; subsurface; fluid; flow

Understanding the movement of fluids in Earth's upper crust, including soil moisture, groundwater, and oil and gas in deep reservoirs is important for a wide variety of reasons. Within the last three decades, geophysical methods have evolved to provide valuable non-invasive approaches for remote sensing of subsurface fluid flow. In the shallow subsurface this has led to improved understanding of numerous processes such as aquifer recharge, contaminant transport, discharge of agricultural nutrients to estuaries, dam seepage, permafrost degradation, and seawater intrusion. The long-term objective of this research program is to improve the sensitivity, and robustness of geophysical methods for monitoring subsurface fluid flow. Over the five-year term of this grant, I plan to focus on monitoring by the time-lapse Electrical Resistivity Imaging (ERI) approach, with special emphasis on the detection and quantification of hazardous concentrated seepage through embankment and rockfill dams used in power generation and mining. Such seepage can lead to internal erosion and piping, which is second only to overtopping as the most common cause of dam failure (Fell, 2005). The need for improved, non-invasive monitoring techniques is growing as the average age of dams rises, and is particularly evident with respect to tailings dams as brought to light by recent high profiles failures in Canada (e.g. Mt. Polley, BC, 2014) and abroad (e.g. Brumadinho, Brazil, 2019). Electrical resistivity surveys can detect concentrated seepage through its effect on moisture content within a dam, or as a consequence of the removal of electrically conductive clay particles by internal erosion. Seepage can also change resistivities seasonally in response to changes in the temperature and total dissolved solids (TDS) content of reservoir water as it following preferential pathways through the dam. Searching for such time-variable anomalies through autonomous long term monitoring can offer improved sensitivity. Regardless, it is a significant measurement challenge to recognize subtle seepage-related resistivity anomalies in the presence of noise and other variability. To begin, my team will conduct a field trial of 3D ERI monitoring at a large hydroelectric power dam in New Brunswick where we have significant research infrastructure already in place. We will pursue improvements in the spatial resolution, depth of exploration and sensitivity of ERI monitoring through innovations in electrode and survey design, statistical techniques for estimating and reducing noise, time-lapse imaging, and time series analysis. In year 3, we will expand our scope to explore the viability of monitoring for hazardous levels of seepage through mining/tailings dams. This will begin with modelling efforts to investigate the types of mining dams and seepage scenarios most amenable to monitoring, prior to undertaking field trials at one or more mine sites.

由于多种原因，了解地球上地壳中液体的运动，包括土壤水分，地下水和油气和气体的运动非常重要。在过去的三十年中，地球物理方法已经发展为提供有价值的非侵入性方法，用于遥感地下流体流动。在浅色地下，这导致人们对诸如含水层补给，污染物的运输，农业营养物质的河口，大坝渗流，多年冻土降解和海水侵入等多种过程的了解得到了进一步的了解。 该研究计划的长期目的是提高地球物理方法的地球物理方法的敏感性和鲁棒性。在这笔赠款的五年期间，我计划通过延时电阻率成像（ERI）方法专注于监视，并特别强调通过发电中使用的堤防和岩石污染物对危险浓缩渗漏的检测和量化和采矿。这种渗漏会导致内部侵蚀和管道，这仅仅是最常见的大坝衰竭原因（Fell，2005年）。随着大坝的平均年龄的增长，对改进，非侵入性监测技术的需求正在增长，并且在尾矿大坝上尤为明显，这是加拿大最近的高档档案失败所揭示的（例如，Polley，BC，BC，2014年）和国外（例如Brumadinho，巴西，2019年）。电阻率调查可以通过对大坝内的水分含量的影响或由于内部侵蚀去除导电性粘土颗粒的影响来检测浓缩渗漏。由于温度的变化和储层水的总溶解固体（TDS）含量，因此渗透还会在季节性上改变电阻率，因为它遵循通过大坝的优先途径。通过自动长期监控搜索这种时间变化的异常，可以提高灵敏度。无论如何，在存在噪声和其他可变性的情况下，识别微妙的渗漏相关电阻率异常是一个重大的测量挑战。 首先，我的团队将在New Brunswick的一个大型水力发电大坝上进行3D ERI监测的现场试验，在那里我们已经建立了重要的研究基础设施。我们将通过电极和调查设计的创新，用于估算和减少噪声，延时成像以及时间序列分析的统计技术来改进ERI监测的空间分辨率，探索深度和敏感性。在第3年，我们将扩大范围，以探索通过采矿/尾矿大坝监测危险渗漏水平的可行性。这将始于建模努力，以调查最适合监测的采矿大坝和渗漏场景的类型，然后再在一个或多个矿场进行现场试验。