Abstract The Makum Coal Basin of Northeast India comprises important coal and shale reserves of upper Oligocene age. A total of twenty samples were collected to evaluate the kerogen type, hydrocarbon generation potential, and thermal maturity through geochemically, organo-petrographically and palynofacies analyses. The samples are characterized by high TOC (total organic carbon) and large S2 (remaining heavier hydrocarbons), meet the required standards as good to excellent generation potential. The coal and shale are marked by mixed Type III-II kerogen with minor occurrence of Type I kerogen, moderate to high hydrogen index (HI) values and are considered to generate thermogenic gas with some condensate oil. The reflectance values indicate samples are mostly immature and close to the oil birth line. The amount of Vt60 grains also suggests that the samples can produce some condensate oil along with thermogenic gas. The Rock-Eval pyrolysis (REP) data stands with the interpretation through petrographic, palynofacies and Fourier Transform Infrared spectroscopy (FTIR) in determining kerogen type and generation potential. The generation potential is also controlled by the degree of organic matters reactivity. The estimated reactivity indicates that besides vitrinite and liptinite, up to 70 vol.% of the inertinite macerals have the potential to generate hydrocarbon. The occurrence of a substantial amount of reactive macerals, i.e. collotelinite, vitrodetrinite, collodetrinte, corpogelinite, alginite, resinite and bituminite within the samples makes them more potential to generate hydrocarbons. The diagram proposed based on our data of macerals and palynofacies assemblages may also be a convenient tool in detecting kerogen type(s) and nature of hydrocarbons.

中文翻译：

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地球化学、有机岩相和孢粉相组合对生烃的影响：印度阿萨姆邦 Makum 煤盆地上渐新统煤和页岩的研究

摘要 印度东北部马库姆煤矿拥有重要的上渐新世煤和页岩储量。共收集了 20 个样品，通过地球化学、有机岩石学和孢粉相分析来评估干酪根类型、生烃潜力和热成熟度。样品的特点是高 TOC（总有机碳）和大 S2（剩余较重的碳氢化合物），符合要求的标准，具有良好的生成潜力。煤和页岩以混合型 III-II 型干酪根为标志，少量出现 I 型干酪根，氢指数（HI）值中等至高，被认为与一些凝析油一起产生热成因气。反射率值表明样品大多不成熟且接近油产线。Vt60 颗粒的数量也表明样品可以产生一些凝析油和热成因气体。Rock-Eval 热解 (REP) 数据支持通过岩相学、孢粉相和傅里叶变换红外光谱 (FTIR) 来确定干酪根类型和生成潜力的解释。发电潜力也受有机物反应性程度的控制。估计的反应性表明，除了镜质体和 liptinite 外，高达 70 vol.% 的惰性物质具有生成碳氢化合物的潜力。样品中大量活性物质的出现，即胶凝体、玻璃体、胶体、胶凝体、褐藻土、树脂岩和沥青岩，使它们更有可能产生碳氢化合物。