利用電性構造模型評估清水地熱區之發電潛能

Using Electrical Resistivity Models to Evaluate Chingshui Geothermal Power Generation Potential

姜智文(C.W. Chiang)

《鑛冶：中國鑛冶工程學會會刊》 61卷1期 (2017/03) Pp. 20-30

https://doi.org/10.30069/MM.201703_61(1).0002

摘要

位於宜蘭平原西南部的清水地熱地區，學界普遍認為是琉球海槽向西延伸的徵兆。1970年間，先後分別由工業技術研究院、台灣中油股份有限公司、行政院國家科學委員會等單位，執行許多相關的地球物理、地質、地球化學等調查工作。調查結果顯示宜蘭清水地區具有極高的地熱資源及潛能。然而，發電效率並未如預期，研判可能與不合適的發電技術及地熱地質構造調查不足所致。本文利用已發表文之大地電磁相關文獻資料為基礎，探討與比對清水地熱區的電性構造差異。利用三維電性構造影像結果，描述清水地熱構造系統，推測清水地熱高潛能區可能埋藏深度約1500公尺，體積約介於1.35×10^9至3.02×10^9立方公尺之間，位於溫泉露頭西南側，小南澳斷層位置處附近。藉由三維空間訊息，搭配地質參數，評估清水地區之地熱流體體積約介於0.5×10^7至1.2×10^9立方公尺之間。最低蘊藏熱能為2.37×10^(11)百萬焦耳(MJ)；最高蘊藏熱能為6.00×10^(11)MJ。最大發電量約五百萬瓦可供利用。

關鍵字

清水地熱 ； 地熱流體 ； 電阻率 ； 大地電磁 ； 地熱潛能

並列摘要

The Chingshui geothermal area southwest of the Ilan plain is identified as a western extension of the Okinawa Trough in the northern Taiwan subduction system. Numerous geophysical, geological and geochemical investigations have been conducted since the 1970s by the Industrial Technology Research Institute, the Chinese Petroleum Corporation of Taiwan and the National Science Council of Taiwan. However, the power generation efficiency has not met initial expectations. It is probably related to inadequate power generation technology and not enough detailed geological surveys. This study aims to discuss the difference of electrical resistivity models in the Chingshui geothermal area based on the published papers. The three-dimensional electrical resistivity image is used to delineate the geothermal system. It is inferred that a high potential area for geothermal energy is buried about 1500 m. The volume of conductive anomaly is in range of 1.35×10^9 to 3.02×10^9 m^3 located in the southwest of the hot spring outcrop, nearby the Xiaonanao fault. The hydrothermal volume is estimated to be between 4.5×10^7 and 1.2×10^9 m^3. The lowest and the highest thermal energy is 2.37×10^(11) and 6.00×10^(11) MJ, respectively. It could produce about 5 million watts of electricity power in maximum.

並列關鍵字

Chingshui geothermal area ； hydrothermal ； electrical resistivity ； Magnetotelluric ； Geothermal potential