Abstract

The transformation of the organic matter (OM) of low-permeable carbon-rich domanik rock of the Romashkino oilfield in sub- and supercritical water (SCW) at temperatures of 320, 374, and 420°C and pressures of 17, 24.6, and 24.4 MPa in a neutral medium has been studied. The original rock with a TOC content of 7% has a high oil generation potential and a low productivity index. The productivity index increases with an increase in the severity of the thermal treatment of the rock, which is due to intense kerogen degradation resulting in the formation of free hydrocarbons that are easy to recover from the rock. In rock extracts, in comparison with the original rock, the amount of saturated and aromatic hydrocarbons increases by more than two times and that of resin–asphaltene substances decreases. Distinctive features of the yields and compositions of rock extracts depending on the temperature of the experiments have been revealed. The highest yield of the extract was observed in the experiment with subcritical water at 320°C and associated with the degradation of resins and more complete extraction of asphaltenes and high-molecular-weight n-alkanes from the rock. Treatment in SCW at 374 and 420°C leads to intensive degradation of the kerogen structure involving the detachment of aliphatic chains from large fragments of kerogen and asphaltene macromolecules to form lower n-alkanes and carbon-rich substances, such as carbenes and carboids. The structure of asphaltenes becomes more condensed and oxidized in the SCW medium at 420°С, leading to a decrease in their paramagnetic properties. Using the EPR technique, the features of hyperfine splitting of the vanadyl complex line on ¹⁴N nitrogen nuclei have been revealed in the spectrum of asphaltenes of the SCW experiment at 420°С, indicating specific changes in their structure.

中文翻译：

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Romashkino油田Domanik岩石有机质在亚临界和超临界水中的转化

摘要

Romashkino油田的低渗透性富碳多曼尼克岩石的有机质（OM）在320、374和420°C的温度，17、24.6和20°C的压力下在亚临界水和超临界水（SCW）中的转化已经研究了在中性介质中的24.4 MPa。TOC含量为7％的原始岩石具有较高的产油潜力和较低的生产率指数。生产率指数随着岩石热处理强度的增加而增加，这是由于强烈的干酪根降解导致形成易于从岩石中回收的游离碳氢化合物所致。在岩石提取物中，与原始岩石相比，饱和烃和芳香烃的含量增加了两倍以上，而树脂-沥青质物质的含量则减少了。已经揭示了取决于实验温度的岩石提取物的产量和组成的明显特征。在320°C的亚临界水进行的实验中，提取物的收率最高，这与树脂的降解以及沥青质和高分子量分子的更完全提取有关。来自岩石的正构烷烃。在374°C和420°C的SCW中进行处理会导致干酪根结构的严重降解，包括脂族链从干酪根和沥青质大分子的大片段上分离，形成低级正构烷烃和富含碳的物质，例如卡宾和类金属。沥青质的结构在420°C的SCW介质中更易冷凝和氧化，导致顺磁性能下降。使用EPR技术，在420°C SCW实验的沥青质光谱中揭示了¹⁴ N氮原子上钒基络合物线的超细分裂特征，表明其结构发生了特定变化。