塔里木盆地侏罗系煤岩热模拟生物标志化合物特征研究

通过对塔里木盆地侏罗系煤岩热模拟实验研究,其结果表明生物标志化合物的组成不仅受其母质的控制,而且还受热成熟度和生油岩的岩性影响。这与生油岩中生物标志化合物先质在不同演化阶段释放出不同碳数生物标志化合物的强度有关。同时,在烃源岩热演化过程中时,不能仅依靠OEP值作为热成熟度的判识指标;正构烷烃峰型在整个热演化过程中呈现出双峰型,前驼峰的主峰碳主要集中在nC₁₆-nC₁₈,而后驼峰则随着模拟温度的升高逐渐增大;煤岩的ΣC_21-/ΣC₂₂₊值与热模拟温度之间呈现出规律性变化;原始煤岩的Pr/Ph值随热模拟温度由250℃～550℃升高,总体呈逐渐降低的趋势。

Biomarker Characteristics in Thermally Simulated Experiment with Jurassic Coal Rock from Tarim Basin, China

A low mature coal (VRr=0.6%, from Manjia'er Depression, Tarim Basin, China in Jurassic system) was subjected to the closed system pyrolysis, in sealed gold tubes, under isothermal temperature conditions, ranging from 250 to 550 ℃ at temperature intervals of 50 ℃ (72 hours). The result shows that the biomarker compositions of the coal rock are dominated not only by mother matters, but also by coal mature and its lithology. This phenomenon is influenced by the intension of the different amount carbon biomarker, which was charged from mother matters of biomarker in generating hydrocarbon rocks at different evolution stages. At the same time, OEP cannot be regarded as a useful guideline of maturity in the thermal evolution of generating hydrocarbon rocks. The peak type of n alkenes presents two peaks in the whole evolution, in which the front peak is mainly mustered from nC ₁₆ to nC ₁₈, but the back peak is increasing while the simulated temperature rises. ΣC ₂₁-/ΣC ₂₂ + of coal rock shows regular changes with the temperature. The Pr/Ph ratio of coal rock falls when the temperature rises from 250℃to 550℃。