应用^(13)C核磁共振波谱分析吐哈盆地干酪根结构变化

Application of^(13)C NMR Spectroscopy to Analysis of Kerogen Pyrolytic Structure in Badaowan Coal of Jurassic in Tuha Basin

吐哈盆地是中国较大的煤系含油气盆地之一,成烃母质大多处于低成熟阶段。为研究油气形成过程中干酪根大分子结构的变化,对盆地侏罗系八道湾组的煤与碳质泥岩干酪根,进行了热解实验,借助于13C核磁共振波谱分析,研究了不同成熟度下干酪根结构的特征与变化。结果表明,随热演化程度的增加,煤与碳质泥岩干酪根中的脂肪族类明显降低、氧接芳碳脱落、芳香结构轻微缩合,在低成熟演化阶段表现尤为明显。脂肪链中亚甲基次甲基含量大于甲基含量,是吐哈盆地轻质低成熟油储量多于低成熟气的主要原因。

Turpan-Hami（Tuha） basin is one of large coal-measure petroliferous basins in China, in which the kerogen of most source rocksis in low-matured stage. By means of 13C NMR spectroscopy analysis and pyrolytic experiment, this paper studied the characteristics andvariation of the kerogen structures in different heating rates and maturities from the Badaowan coal and carbonaceous mudstone of theJurassic in Tuha basin. The results show that such a kerogen is in fact that the aliphatic structure carbons are significantly reduced, theoxygen-aromatic carbons are cracked out and the aromatic structures are slightly condensed, especially in the low-matured evolution stage.The amount of methylene groups is more than that of methyl groups, which could be the main reason for the basin＇s light and low-maturedcrude oil reserves are more than low-matured natural gas.