以松辽盆地南部油伴生CO2气为研究对象,通过组分分析及碳、氧及氮同位素分析,结合中国已有伴生CO2气的含量及同位素数据,研究油伴生CO2气的成因及其意义.结果表明:中国油伴生气中CO2的含量为0～99.53%,大部分在5%以下；油伴生CO2气的δ13 CcO2值为-15.91‰+6.49‰,集中分布于-13‰～ -4‰,以无机成因气为主；松辽盆地南部油伴生CO2气的含量为1.43% ～54.22%,δ13CcO2值为-5.32‰～ -6.76‰,为幔源-岩浆成因；幔源-岩浆成因油伴生CO2气与气藏中的CO2气成因一致,注入时间一般晚于油气大规模充注时间,CO2充注驱油普遍存在；在幔源-岩浆CO2与油气混合成藏地区(如松辽盆地南部)寻找幔源-岩浆CO2充注驱油成因的次生油气藏将是一个新的勘探思路.%Taking the oil-associated CO, samples from southern Songliao Basin as the research object, the genesis and significance of the oil-associated CO2 were studied through component analysis, carbon, oxygen and helium isotopic analysis and combining with the existent oil-associated CO2 content and isotopic data in China. The results show that the CO2 content of oil-associated gas in China is 0-99. 53% , most of which is less than 5%. Carbon stable isotopic value for CO2 ranges from -15. 91‰ to 6.49‰, which mainly distributes in the section of -13‰ to -4‰, indicates that most of CO2 has an inorganic origin. The content and the carbon stable isotopic value for the oil-associated CO2 in southern Songliao Basin range from 1.43‰ to 54.22‰ and -5. 23‰ to -6.76‰, respectively, suggesting a mantle-magmatic origin. As the oil-associated CO2 and CO2 in gas reservoir had the same origin, and the injected-time for oil-associated CO2 was later than the large scale oil and gas generation. The C02 flooding was common in geologic history. In the mixed-reservoir contained mantle-magmatic CO2 and oil, such as the southern Songliao Basin, secondary oil and gas reservoirs could be found with the function of the displacement of CO2.
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