羌塘盆地石炭—二叠系烃源岩地球化学特征讨论

发布时间：2018-06-19 11:27

  本文选题：羌塘盆地 + 石炭—二叠系　； 参考：《中国地质》2017年03期

【摘要】：长期以来,羌塘盆地烃源岩的研究一直限于中生代地层,而对其古生代地层生烃能力一直缺乏系统研究。针对这一问题,本文选择羌塘盆地石炭—二叠系8条剖面的暗色泥岩及碳酸盐岩样品,对其从有机质丰度、有机质类型和热演化程度等方面进行了有机地球化学特征的分析。研究发现,石炭—二叠系可能烃源岩类型包括泥岩和碳酸盐岩两种,其分布总体上受沉积相的控制,碳酸盐岩烃源岩可能为局限台地相发育的泥晶灰岩,而泥质烃源岩主要为三角洲及斜坡相发育的暗色泥岩及凝灰质泥岩。石炭—二叠纪泥岩有机碳含量较高,具有较好生烃能力,大多达到烃源岩标准,尤其是刻莫石炭系剖面及贡日二叠系剖面,大多为中等—好烃源岩。碳酸盐岩有机碳含量总体比较低,为非烃源岩。石炭—二叠系碳酸盐岩烃源岩有机质类型为Ⅱ1型,泥质烃源岩有机质类型主要为Ⅱ2-Ⅲ型。石炭—二叠系烃源岩热演化程度总体较高,除盆地东部刻莫石炭系剖面处在成熟阶段外,大都处在高成熟—过成熟阶段,非常有利于天然气的生成,具备良好的天然气勘探前景。
[Abstract]:For a long time, the study of source rocks in Qiangtang Basin has been confined to Mesozoic strata, but the hydrocarbon generation ability of Paleozoic strata has been lack of systematic study. In order to solve this problem, the samples of dark mudstone and carbonate rock from 8 sections of Carboniferous-Permian system in Qiangtang Basin are selected, and their organic geochemical characteristics are analyzed from the aspects of organic matter abundance, organic matter type and thermal evolution degree. It is found that the Carboniferous and Permian possible source rock types include mudstone and carbonate rock, whose distribution is controlled by sedimentary facies, and carbonate source rock may be mudstone with limited platform facies. The shaly source rocks are mainly dark mudstone and tuffaceous mudstone developed in delta and slope facies. The Carboniferous and Permian mudstones have high organic carbon content and good hydrocarbon generation ability, and most of them meet the source rock standard, especially the Carboniferous and Gongri Permian sections, most of which are intermediate-good source rocks. The organic carbon content of carbonate rock is relatively low and is a non-hydrocarbon source rock. The organic matter type of Carboniferous and Permian carbonate source rocks is type 鈪，

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