Abstract: Based on the analysis of physical properties of Jurassic coal and their evolution regularity in Santanghu basin, Xinjiang, combined with the study on onganic petrology and organic geochemistry of coal-formed oil, this paper considered that the amount of oil generation in the coal is higher than its pore storge capacity at R_o = 0.65% ~ 0. 85%, which requires the forced primary migration of coal-formed oil. The high-pressure of fluid in the coalbed, induced by plastic compaction, resulted in the pore connectivity and microfracture along which coal-formed oil migrated in successive bituminous network. There is the possibility of early generation and early expulsion because of Jurassic coal at early maturity level. The coal-formed oil is characterized by heavy end components, high wax content and high viscosity which is determined by Kerogen, maturity and expulsion mechanism in the coal-bearing Jurassic.

Key words: Xinjiang, Santanghu basin, Coal-formed oil, Primary migration, Jurassic