摘要
在四川盆地川中、蜀南、川西北矿区天然气开发井产层三叠系须家河组、雷口坡组、嘉陵江组和二叠系茅口组取气层气钢瓶样品和气田水样品各22个,对比研究气层气与水溶气碳同位素组成的差异及其地质意义。气层气样品组分和碳同位素组成呈正常的有机成因气特征,而气田水脱溶气比气层气碳同位素组成明显偏重,说明气田水对天然气碳同位素组成有明显的分馏作用。在天然气成藏过程中,如果有较多的天然气从地层水中释放出来混入到气层气中,可能使气藏中天然气碳同位素组成偏重。水溶气碳同位素组成特征为天然气的成因及成藏机理研究提供了新的思路,地层水脱溶气的混入可能是塔里木盆地库车坳陷、四川盆地九龙山地区和威远气田、松辽盆地火山岩气藏天然气碳同位素异常的原因。
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 alkane gas released from gas field water had more13C 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.
出处
《石油勘探与开发》
SCIE
EI
CAS
CSCD
北大核心
2012年第3期313-319,共7页
Petroleum Exploration and Development
基金
国家科技重大专项(2008ZX05001-05-03)
国家自然科学基金资助项目(40672096)
关键词
气田水
水溶气
碳同位素组成
地质意义
gas field water
water-soluble gases
carbon isotope composition
geological significance
