吐鲁番坳陷二叠系烃源岩地球化学与沉积环境的关系

二叠系烃源岩是中国西部吐鲁番坳陷重要的潜在生烃层系。以地表剖面暗色泥岩的分析资料为主，结合部分井下烃源岩样品分析数据，详细探讨了泥岩的微量元素地球化学特征，利用不同岩类烃源岩有机碳含量、有机质类型及饱和烃气相色谱等特征对烃源岩的沉积环境进行了分析。研究认为，吐鲁番坳陷二叠系烃源岩层系沉积时水体的环境为弱还原相—还原相沉积环境。烃源岩有机质中陆源生物占优势，低等水生生物也有大量的分布。油气为还原环境沉积有机质的转化产物，坳陷具有良好的成烃潜力。还原程度强、具一定深度水体的的沉积相带是原始有机质沉积的良好场所，沉积有机质能及时沉积、保存下来，因此，烃源岩大多有机质丰度高；反之，则明显变差。

Relationship between the depositonal environment and geochemistry of Permian hydrocarbon source rocks in the Turpan depression

Permian hydrocarbon source rocks are an important potential hydrocarbon-generating sequence in the Turpan depression, northwestern China. Mainly based on the analytic data of dark mudstone on the outcrop sections, combined with the geochemical data from core samples of hydrocarbon source rocks, the trace geochemistry of mudstone is discussed in detail and the sedimentary environment of the source rocks is analysed by unsing the organic carbon content, organic matter types and saturated hydrocarbon chromatogram parameters of the source rocks. The studies demonstrate that the deposional environment was the weak reducing-reducing one. The terrigenous organisms predominate in the organic matter of the source rocks, and lower aquatic organisms are also present in large quantity. The hydrocarbon is the product of conversion of organic metter deposited in the reducing environment. The depression has a high genetic potential. The sedimentary zones with a strong reducing power and fairly deep water bodies are favorable sites for deposition of primary organic matter, where deposited organic matter can be buried and preserved in time. Therefore most hydrocarbon source rocks contain abundant organic matter and vice versa.