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为研究柴达木盆地第三系未成熟—低成熟石油形成机理,进行了模拟实验。实验分Y、Z两个系列。Y系列用全样模拟,全面反映有机质演化过程,比较接近自然状态。Z系列用除去可溶有机质的样品模拟,主要反映干酪根生烃过程,能够帮助认识干酪根和可溶有机质生烃的特点及其区别。结果表明可溶有机质在较低温度条件下的热演化产物具备了柴达木盆地第三系未成熟—低成熟石油的主要特征——烷烃与芳烃之比较大、异构烷烃和环烷烃含量高、植烷优势十分明显并且其绝对含量也很高、胡萝卜烷和γ—蜡烷含量较高、成熟度参数值小等;而相同温度条件下干酪根降解产物中却有与之完全相反的特点——烷烃与芳烃之比比较小、异构烷烃和环烷烃含量很低、植烷优势不明显且绝对含量也比较低、胡萝卜烷和γ—蜡烷含量很低、成熟度参数值较大等。所以,柴达木盆地第三系未成熟—低成熟石油很可能是在干酪根大量降解之前主要由可溶有机质直接转化形成的。
In order to study the formation mechanism of Tertiary immature-low mature oil in the Qaidam Basin, a simulation experiment was carried out. Experimental points Y, Z two series. Y series with a full sample simulation, a comprehensive reflection of the evolution of organic matter, more close to the natural state. The Z series, simulated by samples with dissolved organic matter removed, mainly reflects kerogen generation and can help to understand the characteristics and differences of hydrocarbon generation from kerogen and soluble organic matter. The results show that the thermal evolution of soluble organic matter at lower temperature possesses the main features of Tertiary immature-low mature oil in the Qaidam Basin - relatively high paraffin to aromatics content, high content of isoparaffin and naphthene , Phytase has obvious advantages and its absolute content is also very high, carrot alkane and γ-wax content is higher, the maturity parameter value is small, etc .; under the same temperature kerogen degradation products have exactly the opposite characteristics - relatively low paraffins to aromatics, very low levels of isoparaffins and naphthenes, insignificant phytochemicals and relatively low absolute levels, low levels of carotenoids and gamma-alkanes, and high values of maturity parameters . Therefore, the Tertiary immature-low-mature oil in the Qaidam basin is likely to be mainly formed by the direct conversion of soluble organic matter prior to the significant degradation of kerogen.