Abstract In February 2019, at the CSIRO In-Situ Laboratory CCS project, a test was conducted where 38 t of gaseous CO2 were injected over 5 days into a fault zone at a depth of approximately 340 m. As a release test, this project enabled the testing and validation of surface and shallow well monitoring strategies at intermediate depths (i.e. depths much deeper than previous release projects and shallower than reservoirs used for CO2 storage). One of the aims of this project is to understand how CO2 would behave at intermediate depths if it did migrate from deeper depths (i.e. from a storage reservoir); the CO2 was not intended to migrate to the shallow subsurface or to surface/atmosphere. To verify that the injected CO2 remained in the subsurface, and to comply with environmental performance requirements on site, a comprehensive surface gas and groundwater monitoring program was conducted. The monitoring strategy was designed such that any leakage(s) to the surface of injected CO2 would be detected, mapped and, ultimately, quantified. The surface air monitoring program was comprised of three different but complementary approaches allowing data to be efficiently collected over different spatial and temporal scales. These approaches included continuous soil-gas chamber measurements at fixed locations, periodic soil-gas chamber measurements on gridded locations and near-surface atmospheric measurements on a mobile platform. The surface air monitoring approaches gave self-consistent results and reduced the risk of “false negative” test results. The only anomalous CO2 detected at the surface flowed from the observation well and could be directly attributed to a breach in the well casing at the injection depth providing a conduit for CO2/water to rise to the surface. Groundwater monitoring program revealed no impact on the groundwater resources attributable to the carbon injection project. Based on this work, we demonstrate that this multi-pronged monitoring strategy can be utilized to minimize the overall resources devoted to monitoring by increasing the number of monitoring approaches and diminishing the resources devoted to each technique. By maximizing the effectiveness of each element of the monitoring program, a cost-efficient and robust monitoring strategy capable of early leak detection and attribution of any leaking CO2 can be achieved.

中文翻译：

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CSIRO 现场实验室：多管齐下的 CO2 地质封存场地表气体和地下水监测方法

摘要 2019 年 2 月，在 CSIRO 现场实验室 CCS 项目中，进行了一项测试，将 38 t 气态 CO2 注入约 340 m 深度的断裂带，历时 5 天。作为发布测试，该项目能够测试和验证中等深度（即比以前发布项目深得多且比用于二氧化碳封存的储层浅得多的深度）的地表和浅井监测策略。该项目的目标之一是了解如果二氧化碳确实从更深的深度（即从储存库）迁移，它在中间深度的表现如何；CO2 不打算迁移到浅层地下或地表/大气。验证注入的 CO2 是否保留在地下，并符合现场环境性能要求，实施了综合地表气体和地下水监测方案。监测策略的设计使得注入的 CO2 表面的任何泄漏都将被检测、绘制并最终量化。地表空气监测计划由三种不同但互补的方法组成，允许在不同的空间和时间尺度上有效地收集数据。这些方法包括固定位置的连续土壤气室测量、网格位置的定期土壤气室测量和移动平台上的近地表大气测量。地表空气监测方法给出了自洽的结果并降低了“假阴性”测试结果的风险。在地表检测到的唯一异常 CO2 是从观测井流出的，可以直接归因于注入深度的井套管裂缝，为 CO2/水上升到地表提供了管道。地下水监测计划显示碳注入项目对地下水资源没有影响。基于这项工作，我们证明了这种多管齐下的监控策略可以通过增加监控方法的数量和减少用于每种技术的资源来最小化用于监控的整体资源。通过最大限度地提高监测计划每个要素的有效性，可以实现经济高效且稳健的监测策略，能够及早发现泄漏并归因于任何泄漏的 CO2。