[Significance]The micromigration of shale oil refers to the phenomenon in which oil is generated in or-ganic-rich layers and expelled at short distances to adjacent,preferable porous and permeable,organic-lean layers in shale systems.Micromigration can effectively improve the oil content and quality of organic-lean layers,even surpassing some organic-rich shale layers based on the exploration practices.Therefore,it is necessary to conduct a systematic study on the micromigration phenomenon of shale oil.[Progress]Based on the current research pro-gress,this paper first identifies the main tracers of shale oil micromigration,which include rock pyrolysis parame-ters,hydrocarbon components,biomarkers,NSO compounds,as well as isotopes.The fundamental principle relies on fractionation between migrated hydrocarbons and retained hydrocarbons based on their geochemical properties.Analysis revealed that micromigration can lead to a dispersed distribution of hydrocarbon generation activation ener-gy in organic-lean shale layers,resulting in an earlier hydrocarbon generation threshold.Moreover,the accumula-tion of light hydrocarbons in a free state in organic-lean layers can further increase the difference of hydrocarbon components between generative units and in-source reservoirs,thereby affecting the oil-bearing and mobility charac-teristics of shale.Based on the effects of petroleum migration and geological zonation,this paper reveals that mi-cromigration occurs throughout the entire process of hydrocarbon generation,expulsion,and retention.It serves as a bridge connecting all elements of petroleum accumulation within shale systems,influencing the differential enrich-ment of shale oil.[Conclusions and Prospects]Comprehensive geochemical and geophysical methods are effec-tive ways to identify micromigration in shale systems and will provide a new perspective for revealing the dynamic differential enrichment of lacustrine shale oil.
关键词
页岩油/微运移示踪/地球化学/页岩油富集
Key words
shale oil/micromigration tracing/geochemistry/enrichment of shale oil
维普
万方数据