页岩油富集与可动性的烃类地球化学制约机制研究

The evaluation on the enrichment and mobility of shale oil is a hot topic in the field of present unconventional petroleum geochemistry. In terms of the importance of hydrocarbon geochemistry on the enrichment and mobility of shale oil, this proposal will focus on the interactions among shale oil generation, shale oil in-source cracking, and shale oil expulsion, as bridged by thermal maturation. The project aims (1) to develop new methods to measure concentrations of the gasoline hydrocarbons adsorbed on the shale and analyze the oxygen-, nitrogen-, and sulfur-contained compounds in polar fractions of shale oil using Fourier Transform Ion Cyclotron Resonance Mass Spectrometry; (2) to describe the kinetics of shale oil generation, especially on the distributions of active energy, and oil types in different stages during maturation; (3)to probe the mechnisms of hydrocarbon geochemical constraints on the enrichment and mobility of shale oil by integrated laboratory results into geological shale profile. The study will be helpful for the construction of "continuous petroleum accumulation" hypothesis, and could be a guidance for shale oil exploration and evaluation.

页岩油富集机制与可动性评价是当前国际非常规油气勘探的焦点问题之一，目前针对性的研究鲜见报道。本项目基于烃类地球化学角度，以我国渤海湾盆地古近系湖相页岩沉积为研究对象，热演化作用为桥梁，页岩油生成、页岩油裂解、页岩容烃排烃三者相互制约过程为主线，建立和发展页岩油轻质组分定量技术与极性组分傅立叶变换离子回旋共振质谱分析技术，精细刻划典型湖相页岩有机质的生烃行为与不同演化阶段页岩油组成特征。以此为基础，结合页岩沉积剖面，提出页岩油富集与可动性的烃类地球化学制约机制。研究成果不仅对"连续油气聚集"理论的完善和发展具有促进作用，而且对页岩油的勘探评价具有现实指导意义。

众所周知，影响页岩油流动性的主要成份是页岩油中胶质沥青质的成份与含量水平。本项目以Rock_Eval热解烃S2为基础，通过测定页岩氯仿沥青提取前后热解烃S2的含量水平获得干酪根贡献热解烃和页岩油胶质沥青质贡献热解烃，结合页岩油轻质烃S1，共同构建三端元图版判识页岩油的可流动性。分子层次的影响主要是干酪根容烃能力和排出油与残留油中杂原子化合物分布的差异性。采用半开放半封闭体系热压生排烃模拟实验，对单一热作用条件下上述二个因素的作用过程开展了详细研究。结果表明，干酪根容烃能力随热成熟度的演变主要受控于其结构的演化，特别是芳构化进程；排烃作用对杂原子化合物在排出油与残留油中的分布存在显著影响，生油窗内主要表现为N1和N1O1类别化合物在残留油中的富集。综合上述因素，可以定义最佳页岩油采出的成熟度区间为等效镜质组反射率1.0-1.2%Ro。目前研究成果已经应用于北美EagleFord页岩油和我国渤海湾盆地束鹿凹陷沙河街组页岩油的勘探评价，并取得良好效果。