塔里木盆地台盆区天然气地球化学特征

GAS GEOCHEMICAL CHARACTERISTICS OF PLATFORM-BASIN REGION IN TARIM BASIN

通过对塔里木盆地天然气样品的分析,系统总结了台盆区的天然气地球化学特征:塔里木盆地台盆区天然气烃类组成以湿气为主,部分地区为干气,湿气分布在塔中、满东—英吉苏、英买力—东河塘、哈得逊和解放渠东—吉拉克等地区,在巴楚、轮南—桑塔木等地区既有干气又有湿气;在非烃气体中以N2和CO2为主,巴楚、塔中、满东—英吉苏、东河塘—英买力、哈得逊等地区以中、高N2含量为特征,在和田河和东河塘地区天然气具高CO2含量特征;天然气碳同位素具有中部轻、周边重的分布特征,塔中、东河塘—英买力、哈得逊等地区的天然气δ13C1值小于-40‰,和田河、满东—英吉苏、轮南—吉拉克等地区的天然气δ13C1值大于-40‰,δ13C2值一般大于-30‰。

Based on the analysis of gas samples of the Tarim basin, the gas geochemical characteristics of the platform-basin region are summarized systematically. The hydrocarbon composition of natural gases is mainly wet gas in the platform-basin region of the Tarim basin,and dry gas in some areas. The wet gas is distributed in central Tarim basin, Mandong-Yingjisu, Yingmaili, Donghetang, Harderson and Jiefangqudong-Jilake. And Bachu and Lunnan-Sangtamu have both wet gas and dry gas. As for non-hydrocarbon components,nitrogen gas and carbon dioxide are dominant. Most areas in Bachu, central Tarim, Mandong- Yingjsu, Donghetang-Yingmaili, Harderson are characterized by the medium-high content of N2, and natural gases in Hetian River and Donghetang have high content of CO2. The carbon isotope distribution of natural gas is characterized by light at the central part and heavier in the peripheral areas. The carbon isotope value of methane is lower than -40‰ in central Tarim, Donghetang-Yingmaili and Harderson, and higher than -40‰ in Hetian River, Mandong-Yingjili, Lunnan-Jilake. The carbon isotope value of ethane is generally higher than -30‰