Abstract Organic matter (OM) from various biogenic origins converts to solid bitumen in-situ when it undergoes thermal maturation. It is well documented that during this process, the ratios of both hydrogen and oxygen to carbon will decrease, resulting in an increase in OM aromaticity and molecular chemo-mechanical homogeneity. Although there have been extensive efforts to reveal molecular alteration occurring to OM during conversion, in-situ and continuous observation of such alterations on naturally occurring samples is missing. Therefore, evaluation of previous results cannot be made independent from natural sample variability. In this study, we identified OM particles (Tasmanites) that are evolving in-situ into solid bitumen in the Bakken Formation. This in-situ bituminization allows examination of a continuous transformation in OM molecular structure at micron-scale using AFM based IR spectroscopy applied at the transition/interface zone. Moreover, contact mode in the AFM was employed to reveal and relate changes in mechanical properties at a similar scale of measurement. Understanding these chemical and mechanical alterations is important to understand shale reservoir properties and better explain hydrocarbon generation, expulsion, and migration processes at the microscale.

中文翻译：

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干酪根原位转化为石油的化学机械快照

摘要 来自各种生物来源的有机物 (OM) 在经历热成熟时会在原位转化为固体沥青。有据可查，在此过程中，氢和氧与碳的比率将降低，从而导致 OM 芳香性和分子化学机械均匀性增加。尽管已经进行了广泛的努力来揭示在转换过程中 OM 发生的分子改变，但缺少对自然发生的样品的这种改变的原位和连续观察。因此，对先前结果的评估不能独立于自然样本变异性。在这项研究中，我们确定了在 Bakken 地层中原位演化为固体沥青的 OM 颗粒（塔斯曼石）。这种原位沥青化允许使用基于 AFM 的 IR 光谱在过渡/界面区域检查微米级 OM 分子结构的连续转变。此外，AFM 中的接触模式用于在类似的测量尺度上揭示和关联机械性能的变化。了解这些化学和机械蚀变对于了解页岩储层性质并更好地解释微观尺度的油气生成、排出和运移过程非常重要。