松辽盆地古龙页岩油储层干酪根的有机元素组成及其N元素的地球化学意义

对青山口组页岩的317件干酪根样品进行了工业、元素及能谱分析，对样品进行两次校正，引入合理评价干酪根C、H、O、N的指标Ccc、Hcc、Occ、Ncc概念。研究结果显示：古龙凹陷青山口组泥页岩Ⅰ型干酪根具有较高的Hcc、Ncc和很低的Occ，而Ⅲ型干酪根的Occ则较高，Hcc、Ncc较低。Ⅱ干酪根的Hcc和Ncc低于Ⅰ型干酪根，而高于Ⅲ型干酪根；Ⅱ干酪根的Occ高于Ⅰ型和Ⅲ型干酪根。Ncc主要以有机官能团（NH3+）方式存在的于黏土的F F纳缝中，而不是存在于黏土晶胞间的无机N（NH4）。微量元素研究表明，古龙青山口组页岩油储层沉积时经历了十几次干旱咸水环境，因为咸水环境有利于形成黏土的F F凝聚，使发育有NH3+官能团的有机质被吸附在黏土片的F F纳缝之间。随着深度的增加，Ncc的克分子量增加速率是Ccc克分子量增加速率的0. 96~2. 04倍，在青山口组1300~2550 m深度内青一段干酪根的Ncc含量明显比上部的干酪根相对高，主要原因与下部青一段藻类较富集有关，其次与Hcc的快速脱落而使Ncc相对富集有关，间接地揭示了青一段生烃能力较上部强。通过研究Ncc可以间接地知道古环境中的咸度、黏土的孔隙类型及其干酪根的来源。经过论证，Occ和Ncc越大，页岩的封存性也就越好，含油气性也越好。因此，Occ和Ncc值可以作为判别页岩油发育程度的指标。古龙页岩油储层的Ncc和Occ的研究可以提供一些重要的沉积环境、地球化学、黏土结构、干酪根有机质类型和成岩成储及成藏等信息，应该受到重视。

Organic element compositions and its N geochemical significances of the kerogen of Gulong shale oil reservoir in Songliao basin

The present study conducted industrial analysis, elemental analysis, and energy spectrum analysis on 317 kerogen samples from the shale of the Qingshankou Formation. The samples underwent two calibrations, and the concepts of Ccc, Hcc, Occ, and Ncc were introduced to effectively evaluate the C, H, O, and N content in the kerogen. The results showed that type- I kerogen exhibited higher Hcc and Ncc values, while having lower Occ values. In contrast, type- III kerogen displayed higher Occ values and lower Hcc and Ncc values in the Qingshankou Formation shale in the Gulong sag area. Kerogen II had lower Hcc and Ncc values than type- I kerogen but higher values than type- III kerogen. Additionally, the Occ value of kerogen II was higher compared to that of type- I and type- III kerogen. Ncc primarily exists in the F- F nanocrystals of clay in the form of organic functional groups (NH+3), rather than in the inorganic N (NH4) between clay cells. Trace element analysis indicated that the shale oil reservoir of the Gulong Qingshankou Formation experienced multiple arid and saltine water environments during deposition. The presence of a saltine water environment facilitated the formation of F- F condensation of clay, leading to the adsorption of organic matter with NH+3 functional groups between the F- F nanocracks of the clay sheet. With increasing depth, the rate of increase in the molecular weight of Ncc was observed to be 0. 96 to 2. 04 times higher than that of Ccc. Notably, the Ncc content of kerogen in the lower section of the Qingshankou Formation at depths ranging from 1300 to 2550 m is significantly higher than that in the upper section. This difference can be attributed to the enrichment of algae in the lower section of the Qingshankou Formation and the relatively higher enrichment of Ncc due to the rapid release of Hcc. This indirectly suggests a stronger hydrocarbon generation capacity in the Qingyi area compared to the upper section. The study of Ncc provides valuable insight into the paleoenvironment salinity, clay pore types, and kerogen sources. It has been demonstrated that higher Occ and Ncc values correspond to better shale storage properties and improved oil and gas- bearing potential. Therefore, Occ and Ncc values can serve as indicators to assess the development level of shale oil. The study of Ncc and Occ in the Gulong shale oil reservoir offers significant information on sedimentary environment, geochemistry, clay structure, kerogen organic matter types, diagenetic reservoirs, and reservoir formation. Consequently, these factors warrant attention in future research.