分散式光纖溫度感測器在地下水污染場址之高解析度井下水文地質調查(I)

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Project title

Project Coordinator/計畫主持人

Yung-Chia Chiu

Funding Organization/主管機關

Environmental Protection Administration

Department/Unit

Institute of Earth Sciences

Website

https://www.grb.gov.tw/search/planDetail?id=12842042

Year

2019

Start date/計畫起

01-08-2019

Expected Completion/計畫迄

30-12-2019

Bugetid/研究經費

1500千元

ResearchField/研究領域

地球科學

由於水文地質環境的非均質性（heterogeneity），增加了土壤與地下水污染場址調查或整治時的困難，欲更加瞭解複雜多變的水文地質狀況，唯有增加量測資料在時、空上之解析度，方能提昇對其之解析能力。有鑑於此，本計畫將引進創新的分散式光纖溫度感測器（distributed fiber optic temperature sensor, FO-DTS）量測技術，並進行現地污染場址的高解析度井下水文地質調查工作。分散式光纖溫度感測器之量測原理為藉由分析雷射光束在光纜（fiber optic cable）中的散射（scattering）訊號而獲得環境中的感測溫度，其主要優點為空間上與時間上的連續性量測，以300,000公尺長的光纖為例，在空間上的解析度可達到每0.25公尺一個量測點，而在時間上的解析度則為每5秒可獲得一筆量測資料，溫度量測的準確度高達0.1oC。在獲取時空上高解析度的溫度量測資料之後，透過熱-水流耦合傳輸模式（coupled heat and flow numerical model）可用以解析井下之透水區段、水文地質分層、地下水流向與流速及優勢水流路徑，對於污染場址之水文地質細部特徵有更清楚的瞭解及掌握，進而提昇污染場址之整治效益。本計畫所預定之試驗模場位於桃園市中壢區的土壤及地下水污染控制場址，其主要污染物為含氯有機溶劑，該場址已進入實場整治階段，預定將使用被動式（passive）與主動式（active）兩種不同的FO-DTS技術進行現地井下量測，期能更清楚掌握水文地質的細部特徵，提昇現場整治工作評估的參考依據之一。利用分散式光纖溫度感測器在環境溫度感測上的高解析度優勢，以及熱能作為地下水示蹤劑之便利性與可行性，將兩者結合並實際應用於污染場址，進行高解析度水文地質調查，將有助於我國在水文地質調查能力之提昇，對於污染場址在人力、經費及時間的成本考量之下，此創新的量測方式將對於土壤與地下水污染調查及整治帶來新的契機。The heterogeneity in hydrogeology increases the challenge when conducting the investigation and remediation at the soil and groundwater contaminated sites. In order to understand the complexity of hydrogeological conditions, plenty of measured data with highly spatial and temporal resolutions are desired. However, no technique or device is existed so far to quickly and inexpensively collect numerous measurements with high resolution at the field. FO-DTS measures environmental temperatures based on the scattering effect of laser transmission through the fiber optic cable. Its major advantage is the continuous measurements with high resolutions in terms of space and time. For a fiber optic cable with the length of 30,000 m, the spatial and temporal resolutions are 0.25 m and 5 second, respectively and the measured accuracy can reach to at least 0.1oC. While the high resolution of data is obtained, a coupled heat and flow numerical model can be combined with the measured temperature to evaluate the permeable section in the borehole, the hydrogeological stratigraphy, groundwater flow direction and velocity, and even preferential flow. These insights of information through high resolution of temperature measurements can provide comprehensive and detailed characteristics about the hydrogeological conditions and then improve the efficiency of remediation at the site. Accordingly, the innovative measuring technique of fiber optic distributed temperature sensor (FO-DTS) was selected and its feasibility will be evaluated in boreholes at a groundwater contaminated site. The site located in Zhongli district in Taoyuan city was contaminated by chlorinated organic solvents and is currently at the stage of remediation. Two different techniques of passive and active FO-DTSs will be applied to the boreholes at this contaminated site. The measured and simulated results can provide detail hydrogeological characteristics and be used as a reference tool for the assessment of remediation. The advantage of using FO-DTS to obtain high resolution of temperatures and the feasibility of using heat as a trace to delineate detailed hydrogeological characteristics will be demonstrated in this study. The combination and application of these two techniques to a real contaminated site can enhance our capability when conducting the investigation of hydrogeology. The innovative technique of FO-DTS can bring a new niche in the remediation at a contaminated site while the manpower, budget, and time are limited.

Keyword(s)

分散式光纖溫度感測器
熱能示蹤劑
地下水污染
水文地質
模場試驗
fiber optic distributed temperature sensor
heat tracer
groundwater contamination
hydrogeology
filed experiment

DSpace CRIS

分散式光纖溫度感測器在地下水污染場址之高解析度井下水文地質調查(I)

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