关键词: 二氧化碳, 幔源成因, 分布规律, 运聚成藏机制, 成藏模式, 松辽盆地

Abstract: The analysis on identifying indicators,such as CO₂ carbon isotope and ³He-to-⁴He ratio,shows that the high content CO₂ of gas reservoir in Songliao Basin can be distinguished as mantle origin.The content of CO₂ is characterized by two points of low and high.CO₂ is mainly concentrated in Yingcheng Formation (K₁yc) and the forth member of Quantou Formation (K₁q⁴) and controlled by regional cap rocks and reservoir quality.In the plane,CO₂ is locally distributed in point shape or thin-and-long banded shape and distinctly controlled by deep-large faults,which is associated with the large basement faults and volcanic rock bodies.The migration and accumulation mechanism of CO₂ was illustrated as follows.The top of deep heat-flow piercement is full of CO₂,and the large basement faults converge downward to the detachment zone and communicate CO₂ gas source.Then,CO₂ migrates upward the proper traps through basement faults and ancient volcanic conduits.The migration pathways of mantle-derived CO₂ can be divided into three combination types,which control the content and distribution of CO₂.The paper established the three-period pool-forming model of CO₂-containing gas pools in Songliao Basin.

Key words: carbon dioxide, mantle origin, distribution law, migration and accumulation mechanism, pool-forming model, Songliao Basin