Recent production of light sweet oil has prompted reevaluation of Devonian petroleum systems in the central Appalachian Basin. Upper Devonian Ohio Shale (lower Huron Member) and Middle Devonian Marcellus Shale organic-rich source rocks from eastern Ohio and nearby areas were examined using organic petrography and geochemical analysis of solvent extracts to test ideas related to organic matter sources, oil–source rock correlation, thermal maturity, and distances of petroleum migration. The data from these analyses indicate organic matter in the Ohio and Marcellus Shales primarily was derived from marine algae and its degradation products, including bacterial biomass. Absence of odd-over-even n-alkane distributions (n-C13 to n-C21 range) in gas chromatograms and low gammacerane index values in Devonian source rocks are similar to those of Devonian-reservoired oils in eastern Ohio, suggesting an oil–source rock correlation. Lower Paleozoic oils from eastern Ohio, in contrast, are characterized by the presence of odd-over-even n-alkane distributions (n-C13 to n-C21 range) and higher gammacerane values, which discriminate them from Devonian shale-derived oils. Thermal maturity estimates from equilibrium(?) biomarker isomerization ratios suggest that some of the Devonian source rock samples are at middle to peak oil window conditions (i.e., approximate vitrinite reflectance values of 0.8%–0.9%). This observation requires local to short-distance (<50 mi) lateral migration for emplacement of Devonian-sourced oils into Devonian reservoirs of eastern Ohio and may impact exploration and assessment of petroleum resources in the Upper Devonian Berea Sandstone.

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俄亥俄州东部泥盆纪页岩的有机地球化学和岩石学：对石油系统评估的启示

轻质甜油的最新生产促使对阿巴拉契亚盆地中部的泥盆纪石油系统进行了重新评估。使用有机岩相学和溶剂萃取物的地球化学分析检查了来自东部俄亥俄州和附近地区的上泥盆统俄亥俄页岩（下休伦成员）和中泥盆纪马塞勒斯页岩有机质丰富的烃源岩，以测试与有机质源，油源岩相关性的思想，热成熟度和石油迁移距离。这些分析的数据表明，俄亥俄和马塞勒斯页岩中的有机物主要来自海藻及其降解产物，包括细菌生物量。泥盆系烃源岩中，气相色谱图中不存在奇数以上的正构烷烃分布（n-C13至n-C21范围）和较低的γ-角ane烷指数值，与俄亥俄州东部的泥盆纪储油相似。源岩相关性。相反，来自俄亥俄州东部的低古生界油的特征是存在奇数-偶数正构烷烃分布（n-C13至n-C21范围）和较高的γ-甘油值，从而将它们与泥盆纪页岩油区别开来。根据平衡（？）生物标志物异构化比率估算的热成熟度表明，泥盆纪烃源岩样品处于中至峰值油窗条件下（即镜质体反射率近似值为0.8％–0.9％）。此观察需要局部到短距离（<