鄂尔多斯盆地长7油层组页岩层系有机质差异富集对地球轨道力的响应

不同地质背景下陆相富有机质页岩非均质性强，导致页岩油富集机理复杂，其关键环节是页岩层系有机质差异富集机制有待阐明。前期研究表明，地球轨道参数的周期变化控制盆地细粒沉积旋回。本项目进一步提出科学问题：作为陆相页岩层系有机质富集的宏观控制因素，地球轨道力促进或抑制页岩层系有机质富集的作用机制尚不明确。鄂尔多斯盆地是研究陆相页岩层系对地球轨道周期响应的理想场所，本项目以长7油层组页岩层系为研究对象，以天文旋回理论为抓手，采用“沉积速率约束下的时间序列分析解码多尺度轨道周期和沉积旋回”技术，建立高分辨率天文地质年代标尺，解析超长地球轨道周期。在时间域分析页岩层系沉积环境波动响应，揭示生产力旋回和保存旋回对有机质差异富集的影响；研究轨道周期叠加后的振幅变化促进或抑制有机质富集的机制，建立受控于地球轨道力的陆相页岩沉积及有机质差异富集模式。为我国陆相页岩油富集主控因素研究提供科学依据。

The strong inhomogeneity of terrestrial organic-rich shales in different geological settings leads to complex shale oil enrichment mechanisms, the key link of which is the differential enrichment mechanism of organic matter in shale formations to be elucidated. Previous studies have shown that the cyclic variation of Earth's orbital parameters controls the fine-grained sedimentary cyclogenesis in the basin. This project further raises the scientific issue that as the macroscopic control factor of organic matter enrichment in the terrestrial shales, the mechanism of Earth's orbital forcing to promote or inhibit organic matter enrichment in the shales is not clear. The Ordos Basin is an ideal place to study the response of terrestrial shales to the Earth's orbital periods, and this project takes the YC 7 oil member in Ordos Basin as the research object. We take the astronomical cycle theory as the starting point, and use the key technique of "decoding multi-scale orbital periods and sedimentary cycles using time-series analysis under sedimentation rate constraints" to establish high-resolution astronomical time scale (ATS), and further verify the ultra-long Earth orbital periods. We analyze the responses of sedimentary environment fluctuation of the YC 7 shales in the time domain, and elucidate the influence of productivity cycling and preservation cycling on the differential enrichment of organic matter. And we reveal the mechanism of amplitude-variation after the superposition of orbital cycles to promote or inhibit organic matter enrichment, and to establish the model of terrestrial shale deposition and organic matter differential enrichment controlled by the Earth's orbital forcing. It will provide a scientific basis for the study of the main controlling factors of continental shale oil enrichment in China.