利用激光扫描共聚焦显微镜冷冻观测技术表征页岩亚微米孔隙中的含油性OA

Light oil is an important target in shale oil exploration and development,but its volatility makes it diffi-cult to observe.In order to solve this problem,a specialized cold stage for laser scanning confocal microscope is de-veloped to determine observation temperature.On this basis,effective observation of oil-bearing property of sub-mi-cron pores of frozen shale samples is achieved through multiple scanning of reflected light,long-wave fluorescence and short-wave fluorescence.The results show that shale oil in Qingshankou Formation of Well A in Gulong Sag of Songliao Basin mostly presents to be irregular,patched and sporadic.The area content of light oil in sub-micron pores is significantly higher than that of heavy components(including heavy oil,resin asphaltene and hydrocarbon-generating parent material),with light/heavy ratio(area ratio)up to 2.5.In observed well intervals,light oil is mainly enriched in argillaceous siltstone and laminated shale,with vertical distribution characteristic of light oil in the upper part and heavy components in the lower part.Based on the distribution of light oil and light/heavy ratio,it is considered that Q4-5 and Q7 oil reservoirs are worthy of attention.Light oil enrichment is controlled not only by hy-drocarbon-generating parent material and the maturity but also by important factors of reservoir space within shale strata series and short-distance migration.Systematic observation of light oil shale and research on distribution laws provide important basis for optimizing exploration and development targets,selecting fracturing intervals in horizon-tal wells and further increasing shale oil production.