The shale oil potential is high in the Permian Lucaogou Formation in Malang Sag

Santanghu Basin. Its genetic mechanism and accumulation patterns are greatly different from those of conventional reservoirs. Migration is a major component of genetic mechanism of shale oil. Based on core and thin section observation

and in combination with geochemical data and geological condition analysis

this paper studied the migration mechanism of shale oil

including dynamic force

pathway

direction

distance

efficiency and so on. Migration effect of shale oil within source rocks is insignificant

thus shale oil reservoirs are not the result of oil migration and accumulation within source rocks. In contrast

vertical migration effect of shale oil out of source rocks is significant. The existence of large active faults may lower the abundance of shale oil in source rock. High formation pressure caused by hydrocarbon generation is the main dynamic force of primary migration. After small scale migration through kerogen network

interlamination and microfractures

most of the oil generated retain in place

and the migration efficiency is very low. On the contrary

in areas where carrier faults are well developed

the oil can migrate vertically along the faults and accumulate in the overlying reservoirs of the Lucaogou Formation. This migration mechanism of shale oil determines the characteristics of shale oil play such as continuous distribution

no obvious oil-water contact

no influence of structure on oil accumulation

and low abundance of oil in areas with active faults.