- 期刊
分散式光纖溫度感測器在溫泉井之高解析度溫度剖面量測應用
Application of Fiber Optic Distributed Temperature Sensor on the High Resolution of Temperature Profiling in the Hot Spring Borehole
摘要
臺灣位於特殊的板塊構造邊緣，擁有豐富的地熱與溫泉資源，然而受到人力與經費的限制，無法針對重要之基礎資料進行時、空中高解析度的量測，導致對於地熱與溫泉資源的分布及其背後之生成與流動至今仍無法完全掌握。在所有相關基礎資料中，地下水溫之量測與分析扮演極為重要之角色，深部地層的溫度分布不僅為地熱系統開發成功與否的關鍵因素，亦為溫泉地區水質監測的重要項目之一。有鑑於此，本研究嘗試將分散式光纖溫度感測器（fiber optic distributed temperature sensor, FO-DTS）實際應用於井下之地下水溫量測，透過FO-DTS在量測上之優勢，獲取垂直方向上高解析度的連續地下水溫度資料。本研究選定臺灣礁溪溫泉區的奇立丹井進行為期3日的連續性量測，透過量測溫度之率定與分析，測試FO－DTS在臺灣溫泉井之適用性與可行性。現地量測結果顯示，FO－DTS可快速獲得井下各深度之溫度變化，具有時間上與空間中之連續性。奇利丹井之井溫隨深度增加而上升，最高溫位於深度77公尺，而井篩處之水溫則呈現為常溫，不隨深度改變。由於奇立丹井位於溫泉地區，整體而言具有較高的地溫梯度，而位於深部的地層其地溫梯度可高達0.67℃／m。FO－DTS的溫度量測結果與傳統溫度計的量測結果非常一致，進一步驗證FO－DTS所量測溫度剖面之正確性。經由本研究之成果，不僅驗證了FO－DTS應用於井下溫度量測之可行性，而FO－DTS在短時間內獲取大量、高精度、高解析度連續性資料之優勢，未來可將其逐漸應用於地下水補注評估、裂隙岩體地下水流及地熱開發等領域，並為水文地質研究開創新的契機。
並列摘要
Taiwan is located at the tectonic boundaries and has abundant geothermal energy and hot springs. Due to the limited manpower and budget, it is still a challenge to collect the fundamental data set with high-resolution in terms of space and time. Without the sufficient data, a comprehensive theory to govern the occurrence and movement of geothermal energy and hot springs does not exist. Groundwater temperature is one of the most important variables when collecting the fundamental data. It plays an important role when developing the geothermal energy. It is also a crucial variable when monitoring the water quality in hot spring areas. Accordingly, an effective and efficient technique to collect temperature data is desired. In this study, an innovative technique of fiber optic distributed temperature sensor (FO-DTS) was selected and applied to measure groundwater temperatures in boreholes. The advantage of FO-DTS is its capability to efficiently obtain hundreds to thousands of temperature measurements with very high-resolution. The CLD well located at Jiashi hot spring area was selected to demonstrate the capability of FO-DTS. Three consecutive days of measurements were conducted in CLD well and then the collected data were calibrated for further analysis. The measured results show that the FO-DTS can obtain continuous temperature profile in terms of space and time efficiently. The temperatures at CLD well increased with the depths and reach the maximum at the depth of 77m. The temperature at the perforated interval kept as a constant and did not change with the depths. The geothermal gradient is high with the value of 0.67℃/m at the deeper aquifer. Compared the temperatures measured between FO-DTS and the conventional approach, the two temperature profiles were almost identical and this comparison verified the accuracy of FO-DTS measurements. This study demonstrated the feasibility of applying FO-DTS to temperature profiling in boreholes. This innovative measured technique with the advantage of highly spatial and temporal resolutions can be applied to the fields of groundwater recharge, groundwater fractured flow, and geothermal energy in the near future and create a great opportunity in hydrogeology research.