• 责任者：Qin Shengfei(Petro China Research Institute of Petroleum Exploration ＆ Development ; Beijing 100083 ; China)
• 刊名：Petroleum Exploration and Development
• 出版年：2012
• 卷期：39(3)
• 关键词：水溶气 ; water dissolved gas ; 碳同位素 ; carbon isotopes ; 四川盆地 ; Sichuan Basin
• 页码：p.313-319
• 图表：illus., 2 tables, 32 refs.
• 分类号：1003
• issnNo：ISSN1000-0747
• isbnNo：CN11-2360/TE

Twenty-two gas and twenty-two water samples were collected from producing wells in the Triassic Xujiahe Formation, Leikoupo Formation and Jialingjiang Formation and the Permian Maokou Formation, in the Middle Sichuan, South Sichuan and Northwest Sichuan gas areas. The difference of carbon isotopes was compared between free gas and water-soluble gas. The component and carbon isotopic composition of the free gas showed normal characteristics of organic gas, while the alkenes gas released from gas field water had more 13C component, indicating that gas field water plays an obvious role of fractionation in carbon isotope of natural gas. During the gas accumulation, if much gas is released from formation water and mixed into free gas, the carbon isotopic composition of free gases may become heavier. So, the carbon isotopic composition of water-soluble gases provides a new perspective for the study of gas origin and gas accumulation mechanism. Mixing of gases released from formation water may be the factor causing the carbon isotope anomalies for natural gases from the Kuqa Depression, Tarim Basin; Jiulongshan region and Weiyuan gas field, Sichuan Basin; and volcanic gas reservoirs of the Songliao Basin.