准噶尔盆地石炭系烃源岩地球化学特征研究

Research of geochemical characteristics of Carboniferous source rocks in Junggar Basin

系统分析了准噶尔盆地石炭系烃源岩有机质丰度、有机质类型及成熟度等特征,应用综合地球化学指标对有机质类型进行判定.石炭系烃源岩有机质丰度高,上统好于下统.其有机质类型表现为下统好于上统,下统以混合偏腐泥型为主,上统以混合型偏腐殖型为主,煤系以腐殖型为主.下统烃源岩几乎都在成熟—过成熟范围内,利于生成成熟油气和凝析油,上统利于生气.并通过纵向上各主要烃源岩层对比,总结出重碳同位素、饱和烃色谱不含β胡萝卜烷、规则甾烷以C27呈显著优势的"V"型分布是石炭系烃源岩的几个标志性地球化学特征.

The abundance,the types and the maturity of organic matter of Carboniferous source rocks in Junggar Basin are discussed,and the types of organic matter are determined by comprehensive geochemical indexes.It is shown that,the abundance of the organic matter is high,and it is higher in upper Carboniferous than in lower Carboniferous,and that in lower Carboniferous,the main type of organic matter is Ⅱ1 type,which is beneficial to the generation of mature oil and gas and condensate oil in higher maturity;in upper Carboniferous,the main type of organic matter isⅡ2 type and Ⅲtype,which is beneficial to gas generation.The few signs of geochemical characteristics of the Carboniferous source rocks are that the carbon isotope is heavy,there is not β-carotane in saturated hydrocarbon chromatogram,and the regular steranes show 'V' shaped distribution with the significant advantage of sterane C27.