The Vaca Muerta Formation, located in the Neuquén.

Basin (Argentina), is one of the most important shale plays in the world. A detailed structural characterization of the formation and evolution of the organic matter during maturation is a must for the correct evaluation of the petroleum potential. The present work studied the molecular characteristics of the organic matter of samples from several wells within the formation. Speciation of organic carbon, oxygen, nitrogen and sulfur present in the rocks was analyzed by XPS and ¹³C solid-state NMR spectroscopy and compared to data from more typical geochemical analyses, including pyrolysis and solid bitumen reflectance. Samples present with high TOC and cover a wide range of maturity levels (%BRo between 0.7 and 1.6%). Differences in carbon aromaticity measured by ¹³C NMR and XPS are discussed. Carbon, nitrogen, and sulfur present in organic isolates were studied and compared to reported data for several other shale formations (Duvernay, Bakken, Woodford and from the Bohai Bay Basin). The results are a novel contribution to the understanding and modeling of organic matter in the Vaca Muerta Formation and can be used to support and improve the classification of kerogens based on their molecular structures.

Vaca Muerta 组，位于内乌肯。

盆地（阿根廷）是世界上最重要的页岩区之一。成熟过程中有机质形成和演化的详细结构特征是正确评估石油潜力的必要条件。目前的工作研究了地层内几口井样品有机质的分子特征。岩石中存在的有机碳、氧、氮和硫的形态通过 XPS 和¹³ C 固态核磁共振光谱分析，并与更典型的地球化学分析数据进行比较，包括热解和固体沥青反射率。样品具有高 TOC 并涵盖广泛的成熟度级别（%BRo 介于 0.7 和 1.6% 之间）。通过¹³测量的碳芳香性差异讨论了 C NMR 和 XPS。研究了有机分离物中存在的碳、氮和硫，并将其与其他几个页岩地层（Duvernay、Bakken、Woodford 和渤海湾盆地）的报告数据进行了比较。这些结果对理解和模拟 Vaca Muerta 组中的有机质做出了新的贡献，可用于支持和改进基于分子结构的干酪根分类。