The molecular composition of petroliferous organic matter and its compositional evolution throughout thermal maturation provides insight for understanding petroleum generation. This information is critical for understanding hydrocarbon resources in unconventional reservoirs, as source rock organic matter is highly dispersed, in contact with the surrounding mineral matrix, and may occur as multiple organic matter maceral types. Here, Raman spectroscopy and optical microscopy approaches were applied to a marginally mature (vitrinite reflectance ~0.5%) sample of the Late Cretaceous Boquillas Shale before and after hydrous pyrolysis (HP) at 300 °C and 330 °C for 72 h. This analytical approach allowed for correlative examination of micro-scale changes in organic matter compositional properties (e.g., aromaticity) for a variety of organic matter macerals across a thermal gradient (from marginally mature into the late oil/wet gas window) at the single particle level. Results indicate that while the examined amorphous organic matter, solid bitumen, and vitrinite particles exhibit different aromatic signatures in the unheated shale, they effectively progress along a similar trend through composition space with thermal maturation. Examined inertinite fragments were generally insensitive to the applied thermal stress, reinforcing the idea that reservoir temperature may be secondary for dictating the molecular composition of inertinite. Additional analysis of Raman spectra for individual organic matter macerals was performed using multivariate curve resolution (MCR) and correlation of standard Raman and reflectance-derived thermal maturity proxies against MCR parameters shows consistent trends. This trend suggests that MCR may be a fast and statistically robust method for extracting compositional information from Raman spectra of sedimentary organic matter, and can be used to construct thermal maturity relationships. These findings inform our understanding of how different petroliferous organic matter maceral types evolve throughout thermal reactions and further demonstrate that Raman spectroscopy combined with petrographic analysis can provide complementary estimates of organic matter composition and thermal maturity.

含油气有机质的分子组成及其在整个热成熟过程中的组成演变为理解石油生成提供了见解。该信息对于了解非常规储层中的油气资源至关重要，因为烃源岩有机质高度分散，与周围矿物基质接触，并且可能以多种有机质基质类型出现。在这里，拉曼光谱和光学显微镜方法应用于晚白垩世 Boquillas 页岩在 300 °C 和 330 °C 下水合热解 (HP) 前后 72 小时的边缘成熟（镜质反射率~0.5%）样品。这种分析方法允许对有机物质组成特性的微观变化进行相关检查（例如，芳香性）在单个粒子水平上跨越热梯度（从边缘成熟到晚期油/湿气窗口）的各种有机物质。结果表明，虽然检测到的无定形有机物、固体沥青和镜质颗粒在未加热页岩中表现出不同的芳香特征，但它们在热成熟的组成空间中有效地沿着相似的趋势发展。检查的惰性碎片通常对施加的热应力不敏感，这强化了储层温度可能是决定惰性分子组成的次要的想法。使用多变量曲线分辨率 (MCR) 对单个有机物质的拉曼光谱进行了额外分析，标准拉曼和反射衍生的热成熟度代理与 MCR 参数的相关性显示出一致的趋势。这一趋势表明 MCR 可能是一种从沉积有机质的拉曼光谱中提取成分信息的快速且统计上稳健的方法，并可用于构建热成熟度关系。这些发现让我们了解了不同的含油气有机质微晶类型如何在整个热反应中演变，并进一步证明拉曼光谱与岩相分析相结合可以提供对有机质成分和热成熟度的补充估计。这一趋势表明 MCR 可能是一种从沉积有机质的拉曼光谱中提取成分信息的快速且统计上稳健的方法，并可用于构建热成熟度关系。这些发现让我们了解了不同的含油气有机质微晶类型如何在整个热反应中演变，并进一步证明拉曼光谱与岩相分析相结合可以提供对有机质成分和热成熟度的补充估计。这一趋势表明 MCR 可能是一种从沉积有机质的拉曼光谱中提取成分信息的快速且统计上稳健的方法，并可用于构建热成熟度关系。这些发现让我们了解了不同的含油气有机质微晶类型如何在整个热反应中演变，并进一步证明拉曼光谱与岩相分析相结合可以提供对有机质成分和热成熟度的补充估计。