Estimation of Groundwater Flow Rate by an Actively Heated Fiber Optics Based Thermal Response Test in a Grouted Borehole
Estimation of Groundwater Flow Rate by an Actively Heated Fiber Optics Based Thermal Response Test in a Grouted Borehole
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DOI：
10.1029/2022wr032672
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发表时间：
2023-01
影响因子：
5.4
通讯作者：
Bo Zhang;K. Gu;P. Bayer;Haibo Qi;B. Shi;Bao-jun Wang;Yuehua Jiang;Quanping Zhou
中科院分区：
文献类型：
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作者：
Bo Zhang;K. Gu;P. Bayer;Haibo Qi;B. Shi;Bao-jun Wang;Yuehua Jiang;Quanping Zhou
含水层的热响应测试（TRT）建立了地下水流量与记录的时间地面加热温度响应曲线之间的关系。实现成熟的水文地质现场测试的一个主要挑战是通过现场加热和温度传感的智能实用解决方案来最大限度地减少钻孔影响。当井眼效应显著时，需要概念来分离它们对记录信号的贡献。当加热和传感装置安装在灌浆钻孔中作为永久测试站时，情况尤其如此。因此，对记录的响应曲线的解释意味着解决通过复合介质的径向传导的瞬态热传递问题。在此，建立了一系列数值模型，以研究水泥浆和主动加热光纤电缆护套对沿加热钻孔沿着测量的模拟热响应的影响。研究结果被用来进一步发展现有的地下水流量估计程序的基础上移动无限线源模型。所开发的方法证明了在一个钻孔附近的银行崩溃网站，穿透不同的含水层的案例研究。因此，发现了随深度变化的显著的局部地下水流量（9 × 10−7-5 × 10−6 m·s−1）。通过TRT解释得出的值与预期速率（2 × 10−6-7 × 10−6 m·s−1）非常匹配，这支持了该估计程序在现场的良好适用性。
The thermal response test (TRT) in an aquifer establishes a relationship between the groundwater flow rate and the recorded temperature response curve of temporal ground heating. A major challenge for achieving a mature hydrogeological field test is to minimize borehole effects by smart practical solutions of in situ heating and temperature sensing. When borehole effects are substantial, concepts are needed to separate their contribution to the recorded signal. This is especially the case when heating and sensing devices are installed in grouted boreholes as permanent testing stations. Interpretation of a recorded response curve thus means solving a transient heat transfer problem with radial conduction through composite media. Here, a series of numerical models are set up to study the effect of the grout and the jacket of an actively heated fiber‐optic cable on the simulated thermal response measured along a heated borehole. The findings are utilized to further develop existing groundwater flow rate estimation procedures based on the moving infinite line source model. The developed approach is demonstrated in a case study in a borehole near a bank collapse site that penetrates different aquifer layers. Accordingly, significant local groundwater flow rates (9 × 10−7–5 × 10−6 m·s−1) are found that vary with depth. The values derived by the TRT interpretation closely match the expected rates (2 × 10−6–7 × 10−6 m·s−1), which supports the good applicability of the estimation procedure in the field.