过成熟页岩气差异富集的古温压和甲烷、乙烷簇同位素约束

本项目围绕动态揭示过成熟页岩气的差异富集过程，拟对科学问题：古流体温压恢复、晚期生气过程重建以及同位素异常成因机制(δ13C1>δ13C2>δ13C3；δ13C1>δ13C-干酪根)进行深入研究。但由于压力演化机制和复合脉体共生关系复杂，难以确保成烃温度和古压力恢复的准确性；同时单一的烷烃组分提供信息过少，使传统研究手段难以满足于阐明晚期生气过程和同位素异常成因。簇同位素在标定成烃温度、约束成因来源和演化过程等方面具明显优势，但国内尚未建立烷烃气的簇同位素测试流程，页岩气甲、乙烷簇同位素研究更鲜有报道。本项目以同位素前沿领域和油气勘探实践相结合，通过完善国内簇同位素测试流程，进行页岩气甲、乙烷簇同位素分析，综合分析其对于成烃温度、生气过程和后期演化路径的约束信息，解释同位素异常成因，在对构造复杂地区古温压恢复的基础上，动态揭示过成熟页岩气形成演化和差异性富集。

In order to dynamically reveal the differential enrichment process of overmature shale gas, this project intends to conduct in-depth research on the existing scientific problems: paleo-fluid temperature and pressure recovery, late gas generation process reconstruction and the interpretation of the isotope anomalies (δ13C1>δ13C2>δ13C3; δ13C1>δ13C-kerogen). Due to the complex pressure evolution mechanism and complex veins symbiosis relationship, the small inclusion size is difficult to measure to ensure accurate analysis of the hydrocarbon generation temperature and paleopressure; meanwhile, the single alkane component makes it difficult for traditional testing methods to clarify the late gas generation process and isotope anomalies. Clumped isotopologue has obvious advantages in accurately calibrating gas generation temperature, constraining its source and later evolution, etc. Then, no reasonable test procedures and research methods have been established in China. Clumped isotopologue studies of methane and ethane in shale gas are rarely reported. This project combines the isotope frontier theory and oil and gas exploration practice. After recovering the paleotemperature and pressure characteristics of shale gas areas, the domestic clumped isotopologue testing process is optimized to study the clumped isotope of methane and ethane (Δ18, Δ13C2H6) in shale gas. This project combines the isotope frontier theory with oil and gas exploration practice, improves the domestic testing process of clumped isotopologue, and performs the clumped isotopologue analysis of methane and ethane of overmature shale gas, based on its constraint information for generation temperature of alkane gas, genesis source, and later evolution path, combined with the recovered paleotemperature and pressure characteristics in complex structural areas, reasonably explain the shale gas isotope anomaly, and dynamically reveal the formation and evolution path, and differential enrichment process of overmature shale gas.