Oil shale as well as shale oil and shale gas are significant energy resources with huge reserves present in different parts of the world. Various geochemical proxies have been applied to assess the petroleum potential of oil shales with samples pre-treated in various ways, e.g. as whole rock or demineralized sample or as solvent extracted rock/kerogen. In this respect, it is important to understand and quantify, how achieved geochemical parameters are influenced by pre-treatment. In this study, a systematic comparison is presented based on a study on i) whole rock, ii) extracted whole rock, iii) kerogen concentrate, and iv) extracted kerogen concentrate obtained after solvent extraction of demineralized shales. In total, seven immature, organic matter-rich samples from the Miocene lacustrine sediments of the Nördlinger Ries impact crater, Germany, were pretreated in this way leading to overall 28 samples. A set of elemental analysis (C, H, N), Rock-Eval pyrolysis, and Curie Point-pyrolysis–gas chromatography–mass spectrometry measurements were performed on these pretreated samples. Mineral matter removal leads to significant increase of total organic carbon, but also thermally evaporable and pyrolytically cracked organic matter (Rock-Eval S1 and S2 peaks). To some extent, labile organic matter represented in the original S2 peak can be destructed by mineral removal with hydrochloric and hydrofluoric acid, as shown by elevated values of PI [S1/(S1 + S2)] after demineralization. The organic matter type tends to be more petroleum-prone with raised hydrogen index (HI) and aliphaticity values after demineralization, while Rock-Eval Tmax values commonly applied as parameters for thermal maturity tend to decrease, though not for all samples.

中文翻译：

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样品制备对未成熟油页岩中基于热解的有机物分析解释的影响


油页岩以及页岩油和页岩气是重要的能源资源，在世界不同地区都有巨大的储量。已经应用了各种地球化学替代指标来评估油页岩的石油潜力，样品以各种方式进行预处理，例如作为整块岩石或脱矿样品或作为溶剂提取的岩石/干酪根。在这方面，了解和量化预处理如何影响所实现的地球化学参数非常重要。在这项研究中，根据对 i） 整块岩石的研究，ii） 提取的整块岩石，iii） 干酪根浓缩物，以及 iv） 溶剂萃取脱盐页岩后获得的提取的干酪根浓缩物进行了系统比较。总共有 7 个来自德国 Nördlinger Ries 撞击坑中新世湖泊沉积物的未成熟、富含有机物的样品以这种方式进行了预处理，总共有 28 个样品。对这些预处理样品进行了一组元素分析（C、H、N）、Rock-Eval 热解和居里点热解-气相色谱-质谱测量。矿物物质的去除导致总有机碳的显著增加，但也会导致热蒸发和热解裂解有机物（Rock-Eval S1 和 S2 峰）的增加。在某种程度上，原始 S2 峰中表示的不稳定有机物可以通过用盐酸和氢氟酸去除矿物来破坏，如脱矿后 PI [S1/（S1 + S2）] 值升高所示。有机物类型往往更容易受到石油的影响，脱矿后氢指数 （HI） 和脂肪含量值升高，而通常用作热成熟度参数的 Rock-Eval Tmax 值往往会降低，但并非所有样品都降低。