松辽盆地古龙页岩油富集耦合机制OA北大核心CSTPCD

Production practice in Daqing Oilfield confirms huge exploration and development potential of Gulong shale oil in Qingshankou Formation of Songliao Basin,but coupling mechanism of shale oil enrichment is still un-clear,restricting the understanding of shale oil accumulation theory and hydrocarbon enrichment areas.Coupling mechanism of Gulong shale oil enrichment is clarified by detailed core description,paleogeothermal restoration,macro and trace elements analysis,field emission scanning electron microscope analysis and 2D nuclear magnetic resonance analysis.The research shows that the enrichment of Gulong shale oil in Songliao Basin is macroscopically and microscopically controlled by several factors coupling.Macroscopically,the enrichment of Gulong shale oil is controlled by 4 geological factors including high-temperature hot basin with paleogeothermal gradient of 43.99～77.28℃/km,large-scale developed hydrogen-rich organic matter-hosted shale,reducing water environment of warm and humid freshwater-brackish water and high sealing capacity of roofs and floors.Microscopically,the en-richment of Gulong shale oil is controlled by synchronous evolution coupling of hydrocarbon generation and accumu-lation with mainline of organic matter maturity.With the increase of shale maturity,kerogen continuously cracks,hydrocarbon generation increases,the proportion of organic fracture pores gradually increases,the proportion of in-organic pores gradually decreases,and the generated oil and gas gradually transform from heavy to light,with the proportion of adsorbed oil decreased and the proportion of free oil increased.When Ro is bigger than 1.3%,the pore wall surface changes from water wet to oil wet,and oil continuously flows from small-scale pores to large-scale pores.The enrichment of Gulong shale oil is controlled by dual coupling of macroscopic geological conditions and microscopic accumulation mechanisms.The research provides important evidence for deepening the understanding on accumulation theory and enrichment areas optimization of Gulong shale oil.