楊燦堯2006-07-252018-06-282006-07-252018-06-282002http://ntur.lib.ntu.edu.tw//handle/246246/11803台灣西部天然氣之氦同位素比值成份 與其所含二氧化碳含量呈線性相關，暗示 著台灣西部至少需要有兩個氣體來源端成 份：（1 ）以含二氧化碳為主的地函源端成 份；（2 ）以甲烷氣為主的地殼源氣體端成 份。可是此二端成份似乎無法解釋台灣西 南部地區所有氣體成份分佈，另一個以含 甲烷氣為主卻有較高氦同位素比值的端成 份是必要的，以解釋中崙濁水潭及八掌溪 氣井氣體成份。此一結果顯示，台灣西部 天然氣成份中之二氧化碳主要源自於地函 源；可是以甲烷氣成份為主的地表天然逸 氣與深鑽氣井之成份，卻有不同的氣體來 源。來自於較深部氣井的甲烷氣，明顯受 到地函源成份影響；而地表甲烷逸氣則以地殼源為主。Representative samples of natural gases, including mud volcano and gas well sources, were collected for analysis of gas composition. Overall, the helium isotopic ratios of the natural gases are proportional to the CO2 contents. Those samples with higher CO2 contents usually exhibit higher 3 He/4 He ratios. For example, the samples collected from deep gas wells usually contain a slight amount of CO2 (up to 42%) and exhibit higher helium isotopic ratios (0.51~2.99Ra) than those from “normal” natural gases at the surface. Hence, at least two components can be identified in natural gases in Taiwan. One is the crustal component, which is methane dominated with very low 3 He/4 He ratios (0.02 Ra); the other is a mantle-derived component with higher 3 He/4 He ratios and enriched in CO2. The composition of most natural gases in Taiwan can be well explained by different proportions of the above two components. However, the other component which dominated with CH4 and high 3 He/4 He ratios is necessary to account for Chung-lun mud pool and Pa-Chiang-Chi gas well samples.application/pdf53553 bytesapplication/pdfzh-TW國立臺灣大學地質科學系暨研究所天然氣泥火山溫泉地函源Natural gasesmud volcanoeshot springsmantle sourcereporthttp://ntur.lib.ntu.edu.tw/bitstream/246246/11803/1/902116M002031.pdf