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阿拉善地区上古生界发育石炭系和二叠系2套烃源岩,通过大量的区域地质调查及有机地球化学、无机地球化学分析,阿拉善地区上古生界烃源岩主要以暗色泥岩及碳酸盐岩为主,石炭系和二叠系的V/(V+Ni)≥0.46和富集Cu、Zn等,表明烃源岩沉积环境为还原环境,且二叠系古盐度值高于石炭系,古生产力变化规律不明显。烃源岩有机质类型较差,体现了腐殖型特征;可能与有机质热演化程度已处于高—过成熟阶段,使得烃源岩类型变差有关。垂向上,石炭系烃源岩有机质丰度优于二叠系;平面上,校育川地区暗色泥岩的有机质丰度最高,而优质的碳酸盐岩烃源岩则主要分布在呼鲁斯太地区。因此,阿拉善地区上古生界具有一定勘探潜力,但主要以寻找天然气为主。
The upper Paleozoic in the Alashan region developed two sets of Carboniferous and Permian source rocks. Through a large number of regional geological surveys and organic geochemical and inorganic geochemical analyzes, the Upper Paleozoic source rocks in the Alashan Region are dominated by dark mudstone and carbon Acid rock salt, V / (V + Ni) ≥0.46 in Carboniferous and Permian, and enrichment of Cu and Zn, indicating that the sedimentary environment of source rock is a reducing environment and the Paleolage ancient salinity value is higher than Carboniferous, paleoclimate variation is not obvious. The organic matter types of the source rocks are poor, indicating humus-type features; it may be related to the fact that the degree of thermal evolution of organic matter is in the high-mature stage and the types of source rocks deteriorate. In the vertical direction, the organic matter abundance of Carboniferous hydrocarbon source rocks is superior to that of Permian. On the plane, the darker mudstone in Xueyuchuan area has the highest organic matter abundance, while the high-quality carbonate source rocks mainly distribute in Huludao area. Therefore, the Upper Paleozoic in the Alashan region has certain exploration potential, but mainly gas-seeking.